SYSTEMS AND PROCESSES FOR THE RECOVERY OF HIGH-QUALITY RARE EARTH CONCENTRATES FROM ACID MINE DRAINAGE

Abstract

In one aspect, the description relates to a continuous process for treating acid mine drainage while simultaneously recovering a high-quality rare-earth pre-concentrate suitable for the extraction of commercially valuable rare-earth oxides. In another aspect, the pre-concentrate contains approximately 0.1% to 5% rare-earth elements on a dry weight basis. In another aspect, the description relates to a method for processing the pre-concentrate to generate a loaded leach solution that does not form gels or emulsions and is suitable for processing by solvent extraction. In yet another aspect, the description relates to a system and plant for carrying out the described process. In yet another aspect, the description relates to a composition containing rare-earth elements produced by the process described herein.This summary is intended as an exploratory tool for search purposes in the particular technique and is not intended to be limiting to the present description.

Description

SYSTEMS AND PROCESSES FOR THE RECOVERY OF HIGH-QUALITY RARE EARTH CONCENTRATES FROM ACID MINE DRAINAGE CROSS-REFERENCE WITH RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 62 / 875,502 filed July 17, 2019 and U.S. Utility Application No. 16 / 795,471 filed February 19, 2020, each of which is incorporated in full by reference in this description. STATEMENT REGARDING RESEARCH OR DEVELOPMENT SPONSORED BY THE FEDERAL GOVERNMENT This invention was made with the support of the United States Government under grant number DE-FE0031524, awarded by the United States Department of Energy. The United States Government has certain rights in the invention. BACKGROUND OF THE INVENTION Rare earth elements (REEs) are useful and necessary for manufacturing batteries that power hybrid and electric vehicles, catalytic converters, computer memory, fluorescent lighting and lasers, smartphones and tablet computers, cameras (including electronic components and lenses), e-readers, magnets, night-vision goggles, communications and GPS equipment, military applications (including precision-guided weapons and vehicle armor), aircraft engines, personal protective equipment, and other applications, including defense applications. Some REEs can be used in air pollution control mechanisms, oil refineries, medical diagnostic equipment such as X-ray and MRI machines, as phosphors, as catalysts, as components of ceramics and paints, and / or as polishing compounds.Although renewable energy sources (REEs) and critical minerals (CMs) can be extracted from many waste products and minerals, few such resources are economically attractive. Given the current and potentially ongoing export controls on REEs from China, developing domestic sources of REEs would be advisable. Acid mine drainage (AMD) is a pollutant generated by coal and other mining operations and must be treated in accordance with federal and state clean water regulations to adjust pH and remove metal ions, including iron, aluminum, and manganese. There are many instances of acid mine drainage (AMD) in the northern, central, and southern Appalachian watersheds, as well as in the Illinois coal basin and other parts of the United States. In the northern and central Appalachian coal basins, water pollution from AMD is the leading cause of river degradation. Processes for treating AMD to meet regulatory compliance have been the subject of massive investment in research and infrastructure since the early 1970s.It is estimated that in the Appalachian states alone, more than 50 new, large-scale wastewater treatment plants will be installed over the next 10 years in an effort to address the growing pollution of rivers. Although trace amounts of reactive oxygen species (RES) are known to exist in wastewater, a reliable method for concentrating and extracting them has not yet been developed. Despite advances in the treatment of acid mine drainage, there is still a shortage of methods capable of recovering radioactive waste (REE) from acid mine drainage that are environmentally sound, cost-effective, scalable, and adaptable to existing facilities. Ideally, the method would produce negligible amounts of naturally occurring radioactive material and / or other harmful waste, as well as reduce river pollution. Additionally, it would be desirable for the method to be adaptable for extracting REE from other sources. It would also be advantageous for the process to operate continuously and without the formation of insoluble material such as aluminosilicate gels. Furthermore, having a domestic source of REE would be desirable. This need, along with others, is addressed by the present description. SUMMARY In accordance with the purpose(s) of this description, as incorporated and fully described herein, the description, in one aspect, relates to a continuous process for treating acid mine drainage to meet Clean Water Act requirements while simultaneously recovering a high-quality rare earth concentrate suitable for the extraction of commercially valuable rare earth oxides. In another aspect, the high-quality rare earth pre-concentrate is approximately 0.1% to approximately 5% total rare earth elements (REE) on a dry weight basis. Also described herein is a method for processing the rare earth pre-concentrate to generate a loaded leach solution that does not form GC-Cs or emulsions and is suitable for processing by solvent extraction.In another aspect, this description outlines a system that includes a plant capable of carrying out the method described herein. In yet another aspect, this description outlines a composition containing the REE prepared by the process described. Other systems, methods, features, and advantages described herein will be apparent to a person skilled in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, fall within the scope of this description, and are protected by the appended claims. Furthermore, all optional and preferred features and modifications of the described embodiments may be used in all aspects of the description taught herein. Moreover, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments, are combinable and interchangeable with one another. BRIEF DESCRIPTION OF THE FIGURES Many aspects of this description can be better understood with reference to the following figures. The components in the accompanying figures, which illustrate one or more illustrative modes, are not necessarily to scale; rather, the emphasis is on clearly illustrating the principles of this description. Furthermore, in the figures, the same reference numbers designate corresponding parts across the various views. Figures 1A-1B show a representative mobile Rare Earth Element / Critical Mineral (REE / CM) extraction unit in an acid mine drainage (AMD) treatment plant, useful in an aspect described herein. Figure 1A: trailer containing the extraction unit. Figure 1B: interior of the trailer showing plate and frame filters (foreground) and mixing tanks (background). Figures 2A–2B show a representative analysis of samples treated by the described process. Figure 2A: Example of DAM preconcentrate composition and oxide composition after processing through an acid leaching / solvent extraction (ALSX) process as described herein. Elements constituting less than 0.01% of the sample (i.e., Co, Mg, Mn, Ni) are not shown. Figure 2B: Elemental distribution within the mixed rare earth oxide fraction (MREO). Red labels indicate critical minerals. Gray tones indicate light rare earth elements (LREE, 35.3%), while colored segments represent heavy rare earth elements (HREE, 64.7%). The sample was not acid-washed prior to analysis. Figure 3 shows a schematic flow diagram of a process described in this description. Conventional DAM treatment is shown on the left (blue background) with REE / CM recovery and concentration on the right (green background). Figures 4A-4B each show illustrative aspects of a rare earth extraction facility (REEF). Figure 5 shows the ALSX units before (left) and after (right) the development and implementation of the measures developed to control slag formation. Figure 6 is a flow diagram showing individual stages according to one aspect of the integrated upstream concentration and acid leaching / solvent extraction process as described herein. Figures 7A-7B show representative sensitivity analyses of the described processes. Figure 7A shows a representative sensitivity analysis of the maximum acid dose as a function of sludge feed quality. Figure 7B shows a representative sensitivity analysis of the equilibrium point mobility distance as a function of feed quality and moisture content. Figure 8 shows a sensitivity analysis of ALSX operating costs as a function of plant size and feed quality. Figure 9 shows a photographic image of a representative high-quality rare earth concentrate (80%) produced by a process described in this description. Figure 10 is a flowchart of a representative mobile plant operating principle, as described herein, for implementing the methods and processes outlined. The Omega Clarifier, as shown in the figure, is a component of a specific conventional DAM treatment plant in West Virginia. Figure 11 shows an illustrative bench-scale acid leaching module as described in this description. Figure 12 shows the representative gel formation of loaded leaching solution (PLS) on a tray filter at pH 3.0. In one respect, the method described herein does not produce gel formation. Figures 13A-13B show representative components useful in the processes described herein. Figure 13A shows a 150 mm laboratory-scale filter press; and Figure 13B shows a 420 mm filter press. Figures 14A-14B show photographic images of aspects of PLS ​​filtration. Figure 14A shows a representative PLS solution after filtration on plate and rack filters; and Figure 14B shows a representative filter cake from the cleaning of a 2 ft³ filter press used to process the PLS. Figure 15 is a flow diagram showing the acid leaching process used to generate PLS as described in this description. Figure 16 shows an illustrative solvent extraction module useful in the processes described in this description. Figure 17 shows the formation of a slag layer in an extraction settler during the DLM control test (a site used as a source of DAM solids treatment). Figure 18 is a representative flow diagram for a solvent extraction module described in this description. Figure 19 shows an illustrative precipitation module useful in the processes described in this description that can be used to recover REE from the separated raffinate. Figure 20 shows a diagram of a representative precipitation process useful in the methods and processes described in this description. Figure 21 shows a photographic image of a representative MREO product with a 62% quality produced by an example process as described in this description. Figure 22 shows representative data for the distribution of REE DAM concentrations as a function of pH, where CAPP and NAPP represent, respectively, REE-enriched Central Appalachian and Northern Appalachian DAM sources. Figure 23 shows a flow diagram of a portion of a described process, beginning with the transfer of raw DAM feedstock to a separator and ending with the transfer of a loaded leaching solution (PLS) to the described solvent extraction process. A number of optional steps for scandium recovery are included. Figure 24 shows a flow diagram of the described process. In some aspects, a second separation and concentration stage is applied if desired to collect a scandium-enriched solid concentrate. The additional advantages of the invention will be partly set forth in the following description, and partly will be apparent from the description, or can be learned through the practice of the invention. The advantages of the invention will be understood and achieved by means of the elements and combinations particularly highlighted in the appended claims. It should be understood that the foregoing general description and the following detailed description are merely illustrative and explanatory and are not restrictive of the invention as claimed. ζ / αηηη / ζζηζ / Ε / γίΛΐ DETAILED DESCRIPTION Many modifications and other variations described herein will be obvious to a person skilled in the art to which the described compositions and methods belong, who benefits from the teachings presented in the preceding descriptions and associated figures. It should therefore be understood that the descriptions are not limited to the specific variations described and that modifications and other variations are intended to be included within the scope of the appended claims. A person skilled in the art will recognize many variations and adaptations of the aspects described herein. It is intended that these variations and adaptations are included in the teachings of this description and are covered by the claims herein. Although specific terms are used in this description, they are used only in a generic and descriptive sense and not for purposes of limitation. As will be evident to those skilled in the technique upon reading this description, each of the individual modalities described and illustrated herein has discrete components and characteristics which can be easily separated from, or combined with, the characteristics of any many other modalities without departing from the scope or spirit of this description. Any method mentioned may be performed in the order of the events mentioned or in any other logically possible order. That is, unless expressly stated otherwise, no method or aspect set forth herein is intended in any way to be interpreted as requiring its steps to be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps must be limited to a specific order, no order is intended to be inferred in any respect. This applies to any possible unexpressed basis for interpretation, including questions of logic regarding the arrangement of steps or the flow of operations, the plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described. All publications mentioned in this description are incorporated by reference to detail and describe the methods and / or materials in relation to which the publications are cited. The publications discussed in this description are provided solely for the purpose of description prior to the filing date of this application. Nothing in this description should be construed as an admission that the present invention is not entitled to precede such publication by virtue of a prior invention. Furthermore, the publication dates provided in this description may differ from the actual publication dates, which may require independent confirmation. Although aspects of the present description may be described and claimed in a particular legal class, such as the legal class of the system, this is only for convenience, and a person skilled in the art will understand that each aspect of the present description may be described and claimed in any legal class. It should also be understood that the terminology used in this description is for the purpose of describing particular aspects only and is not intended to be exhaustive. Unless otherwise defined, all technical and scientific terms used in this description have the same meaning as commonly understood by a person skilled in the art to which the described compositions and methods belong. It should further be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the description and the relevant technique and should not be interpreted in an idealized or overly formal sense unless expressly defined in this description. Before describing the various aspects of this description, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in this description. DEFINITIONS As used herein, "comprising" should be interpreted as specifying the presence of the stated characteristics, whole numbers, stages, or components indicated, but not excluding the presence or addition of one or more other characteristics, whole numbers, stages, or components, or groups thereof. Furthermore, each of the terms "by," "comprising," "comprising," "consisting of," "including," "involving," "involving," and "such as" is used in its open, non-limiting sense and may be used interchangeably. Additionally, the term "comprising" is intended to include examples and aspects covered by the terms "consisting essentially of" and "consisting of." Similarly, the term "consisting essentially of" is intended to include examples covered by the term "consisting of." As used in the description and in the appended claims, the singular forms “a”, “an” and “the” include plural referents unless the context clearly indicates otherwise. Thus, for example, the reference to a rare earth element includes, but is not limited to, mixtures of two or more such rare earth elements and the like. It should be noted that proportions, concentrations, quantities, and other numerical data may be expressed in this description in an interval format. It is further understood that the endpoints of each interval are significant both in relation to and independently of another endpoint. Additionally, it is understood that there are a number of values ​​described in this description, and that each value is further described as being “approximately” that particular value in addition to the value itself. For example, if the value “10” is described, then “approximately 10” is also described. Intervals may be expressed in this description as being from “approximately” one particular value and / or “approximately” another particular value. Similarly, when values ​​are expressed as approximations by using the antecedent “approximately,” it is understood that the particular value is a different aspect.For example, if the value “approximately 10” is described, then “10” is also described. When expressing an interval, an additional aspect includes "from one particular value and / or up to another particular value." For example, when the stated interval includes one or both limits, the intervals that exclude one or both of the included limits are also included in the description. For instance, the phrase "xay" includes the interval from 'x' to 'y' as well as the interval greater than 'x' and less than 'y'. The interval can also be expressed as an upper limit, for example, "approximately x, y, z, or less," and should be interpreted to include the specific intervals of "approximately x," "approximately y," and "approximately z," as well as the intervals of "less than x," "less than y," and "less than z."Similarly, the phrase 'approximately x, y, z, or greater' should be interpreted to include the specific intervals of 'approximately x', 'approximately y', and 'approximately z' as well as the intervals of 'greater than x', 'greater than y', and 'greater than z'. Furthermore, the phrase "approximately 'x' to 'y'", where 'x' and 'y' are numerical values, includes "approximately 'x' to approximately 'y'". It should be understood that such an interval format is used for convenience and brevity and, therefore, should be interpreted flexibly to include not only the numerical values ​​explicitly stated as the interval limits, but also all individual numerical values ​​or subintervals within that interval as if each numerical value and subinterval were explicitly stated. To illustrate, a numerical interval of approximately 0.1% to 5% should be interpreted as including not only the explicitly stated values ​​of approximately 0.1% to approximately 5%, but also individual values ​​(e.g., approximately 1%, approximately 2%, approximately 3%, and approximately 4%) and the subintervals (e.g., approximately 0.5% to approximately 1.1%; approximately 5% to approximately 2.4%; approximately 0.5% to approximately 3.2%; and approximately 0.5% to approximately 4%).4%, and other possible subintervals) within the indicated interval. As used herein, the terms approximately, approximate, in or about, and substantially mean that the quantity or value in question may be the exact value or a value that provides equivalent results or effects as stated in the claims or taught herein. That is, it is understood that quantities, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximated and / or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding, measurement error, and the like, and other factors known to those skilled in the art, so as to provide equivalent results or effects. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined.In such cases, it is generally understood, as used herein, that "approximately" or "about" means the stated nominal value plus 10% variation unless otherwise stated or inferred. Generally, a quantity, size, formulation, parameter, or other quantity or characteristic is "approximate," "about," or "about" whether or not it is explicitly stated to be so. It is understood that when "approximately," "about," or "at" or "about" is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless otherwise specifically stated. As used in this description, the term effective quantity refers to an amount sufficient to achieve the desired modification of a physical property of the composition or material. For example, an effective quantity of a buffer refers to an amount sufficient to achieve the desired improvement in the property modulated by the formulation component, such as achieving and maintaining a desired pH of the solution. The specific level, expressed as a weight percent in a composition, required as an effective quantity will depend on a variety of factors, including the quantity and type of buffer, the size of the processing plant (i.e., start-up, mobile, or commercial scale), the quantity and type of raw material to be treated, and the final use of the recovered REE during the process. As used in this description, the terms “optional” or “optionally” mean that the event or circumstance subsequently described may or may not occur, and that the description includes examples where such event or circumstance occurs and examples where it does not. As used in this description, the term rare earth element (REE) refers to a composition comprising one or more rare earth elements, including one or more lanthanide elements, namely lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. It may also occasionally include scandium and yttrium. Scandium and yttrium are often found in the same ore deposits as lanthanides and also share some similar chemical properties. Rare earth elements are useful in a variety of applications in the electronics, defense, and medical industries, as well as in other applications. An oxide of a rare earth element is a rare earth oxide and may be used for analytical purposes or as a component of ceramics, catalysts, and / or coatings, among other uses.It should be understood that when reference is made to rare earth elements, any of the elements may be present in an elemental or zero-valence state, or in an ionized or valence state associated in the art with the individual element, and all forms are understood to be collectively included within the meaning of rare earth elements. Furthermore, it should be understood that reference to any individual rare earth element—that is, any of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, and includes scandium and yttrium—may be present in an elemental or zero-valence state, or in an ionized or valence state associated in the art with the given element, and all forms are understood to be collectively included within the meaning of reference to that element.For example, a reference to lanthanum, an element such as lanthanum, a composition comprising lanthanum, and the like, is understood to include any or all forms of lanthanum such as La0, La+1, La+2, and La+3. It is further understood that a reference to any given rare-earth element includes all isotopic forms of the element. As used in this description, the terms heavy rare earth elements and HREEs may be used interchangeably and refer to yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. It should be understood that yttrium may be classified as a heavy rare earth element due to its chemical properties and aggregation with other HREEs in minerals, but it may also be classified as a light rare earth element due to its lower atomic weight. As used in this description, the terms light rare earth elements and LREE can be used interchangeably and refer to scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium. In some respects, these designations may differ slightly, but they are generally based on atomic weight. As used herein, the terms total rare earth elements and TREE may be used interchangeably and refer to the total REE present in a described composition or product of a described process, method, or device, wherein the REE comprises Critical minerals (CMs), as used herein, include minerals important to national security and the economy. REEs are considered critical minerals due to their numerous industrial uses. Other critical minerals, including but not limited to cobalt, gallium, germanium, hafnium, indium, niobium, rhenium, rubidium, tantalum, and tellurium, may also be purified and concentrated using the described process. As used herein, gangue metals and other materials are unwanted materials that accompany or are added to the REE that is isolated and concentrated by the process described. In one respect, in the present process, gangue material may include, but is not limited to, aluminum, calcium, magnesium, manganese, silicon, chloride, and the like. In some respects, gangue materials may have little or no economic value. In other respects, gangue materials may have industrial uses, but their presence alongside the more valuable REE can complicate the recovery of the REE. Acid mine drainage (AMD), as used herein, refers to acidic water flowing out of mines such as, for example, metal or coal mines. In one respect, AMD intensifies in scale and scope when construction, mining, and other land-disturbing activities occur in and around rocks containing sulfide minerals. AMD can have high concentrations of metal ions that can cause detrimental effects to aquatic environments, especially in combination with a low pH. AMD from coal mines and other sources often also contains trace amounts of reactive oxygen species (RES). DAM precipitate (DAMp), as used herein, refers to a byproduct of DAM treatment. In one aspect, DAMp contains REE but may also contain gangue metals such as, for example, iron and aluminum. In one aspect, DAMp contains from approximately 0.06% to approximately 0.1% REE. As used herein, enriched DAM precipitate (DAMpe) refers to a DAM product that has from approximately 0.1% to approximately 5% REE on a dry weight basis. In another aspect, DAMpe has a lower gangue metal content than DAMp. A raw material as used in the present description is a natural raw material processed to recover REE and other valuable components (e.g., CM). A raw material may be too toxic to be released into the natural environment, and in one respect, the described process can remove commercially valuable components from the raw material while simultaneously transforming the raw material into one suitable for environmental release. As used in this description, loaded leach solution (PLS) is water with an acidic pH and a high metal content. In one respect, PLS can be processed using various purification technologies, including but not limited to solvent extraction, ion exchange resins, selective precipitation, and fractional crystallization, to remove and / or concentrate the metals. In some respects, PLS may have a high solids content and may require filtration before further processing. Meanwhile, raffinate refers to a chemically separated product from which one or more components have been removed. In one respect, following solvent extraction as described herein, the raffinate is the aqueous component depleted in REE content. In another respect, the raffinate may include unwanted gangue material. As used in this description, GEOTUBE® refers to a dewatering device made of a polypropylene fabric that can be produced according to the needs of a particular project or industry. In one aspect, the sludge or other material to be separated is pumped into a GEOTUBE® container, and a fabric liner keeps the solids trapped inside while the filtered water escapes and can be directed to a treatment facility. Unless otherwise specified, the temperatures referred to in this description are based on atmospheric pressure (i.e., one atmosphere). Loaded leach solution (PLS) composition. In several respects, this description refers to a loaded leach solution (PLS) composition, for example, a PLS composition, obtained from acid mine tailings (AMT) as feedstock using the processes, methods, and systems described herein. In a further respect, the described PLS composition is enriched in one or more renewable energy sources (REE) compared to the AMT feedstock used. The described PLS composition can be used in further stages, as described herein, to further enrich or purify one or more REE materials. ζ / αηηη / ζζηζ / Ε / γίΛΐ Additionally, the composition of PLS ​​can vary depending on the composition of the DAM raw material used. Representative average values ​​determined experimentally for multiple PLS compositions prepared using the processes, methods, and devices described are shown in Table 1.1 below. ζ / αηηη / ζζηζ / Ε / γίΛΐ Table 1.2: Distribution of Elemental Concentrations of Typical PLS Samples. Element Number of Samples Mean* Median* Min.* Max.* Standard Deviation* Confidence Interval* Al 33 4701.78 2736.24 2130.78 21 446.32 4637.25 1644.30 Ca 33 1008.67 745.22 590.10 2605.74 537.24 190.50 Co 33 43.56 24.04 18.43 195.29 46.09 16.34 Fe 33 363.78 4.96 2.20 3823.39 961.16 340.81 Mg 33 3068.26 2353.81 164.19 13 134.87 3109.94 1102.74 Mn 33 987.22 707.77 74.44 3689.29 963.37 341.60 Na 33 9225.59 9619.27 47.55 28 475.75 6479.95 2297.69 Ni 17 56.25 49.94 38.63 91.94 16.24 8.35 Yes 33 346.34 73.96 32.54 3559.26 783.14 277.69 Zn 17 242.70 110.26 85.24 686.61 222.97 114.64 SO4 33 1059.86 1011.56 25.39 3141.38 518.79 183.96 C1 33 9.38 5.06 2.04 77.87 12.86 4.56 Se 31 552.50 133.92 74.75 2822.18 785.28 288.04 Y 33 23 970.81 13 527.36 7151.53 111 224.38 24 997.97 8863.89 La 33 6221.13 2697.71 1477.79 32 650.27 7826.85 2775.28 Ce 33 16,906.87 7749.36 4906.65 86 414.33 20 395.50 7231.93 Pr 33 2405.26 1281.05 782.96 10 803.77 2498.28 885.85 Nd 33 11 344.41 6492.20 3688.07 48 145.36 10 774.42 3820.44 Sm 33 3178.51 2087.37 1133.53 12 001.32 2548.86 903.78 Eu 33 838.37 530.82 302.10 3 223.56 688.45 244.12 Gd 33 4850.06 3046.42 1820.15 18 229.43 3932.68 1394.47 Tb 33 789.93 484.26 339.07 3 021.65 660.37 234.16 Dy 33 4491.55 2574.64 1995.76 18 229.21 4100.69 1454.04 Ho 33 885.34 487.86 354.92 3639.79 830.31 294.41 Er 33 2317.29 1227.86 908.26 10 032.59 2302.52 816.44 MT 33 296.40 151.07 112.90 1291.24 298.81 105.95 Yb 33 1645.19 827.17 638.35 7380.85 1707.64 605.50 Mon 33 242.53 123.16 91.79 1100.99 251.70 89.25 Th 25 37.28 6.14 0.06 322.19 75.65 31.23 U 33 359.75 267.88 198.47 1205.17 219.05 77.67. *Units for aluminum to chloride are mg / L. Units for scandium to uranium are pg / L. Table 2 below shows representative average values ​​that were experimentally determined for multiple PLS compositions prepared using the processes, methods, and devices described. Table 1.2. Typical composition of PLS. ζ / αηηη / ζζηζ / Ε / γίΛΐ Phase 5 acoosa 20'0852 mg / L %TREE Ganga mg / L Se 0.3 1.3% Al 2625 7 Y 5.7 24.5% Fe 10.2 La 1.5 6.3% Mn 84.6 Ce 3.8 16.2% Ni 41.2 Pr 0.7 3.1% Si 25.7 Nd 2.9 12.6% Zn 126.6 10 Sm 1.3 5.5% 2913.9 Eu 0.3 1.4% Gd 1.9 8.3% Other ions Tb 0.4 1.6% Ca 1546 0 Dy 1.9 8.0% Mg 528.6 Ho 0.4 1.7% Na 27 548.2 Er 1.0 4.3% SO4 0.0 15 Tm 0.2 0.7% Cl 5.4 Yb 0.9 3.9% 29 628.2 Lu 0.1 0.6% TREE 23.3 Co 17.9 77% TREE+Co 41.2 Th+U 0.4 1.8% 20 In a further aspect, the PLS composition comprises TREE present in a concentration of at least approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 30 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L,approximately 45 mg / L, approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range spanned by any two of the above values; or any set of the above values; wherein TREE is understood to comprise at least three of: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In an additional aspect, the PLS composition comprises TREE present at a concentration of less approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L,approximately 49 mg / L, approximately 50 mg / L; or a range spanned by two, any of the above values; or any set of the above values; wherein it is understood that TREE comprises at least four of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In an additional aspect, the PLS composition comprises TREE present at a concentration of less approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, ζ / αηηη / ζζηζ / E / γίΛΐ approximately 49 mg / L, approximately 50 mg / L; or a range encompassed by any two of the above values; or any set of the above values; wherein it is understood that TREE comprises at least five of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In an additional aspect, the PLS composition comprises TREE present at a concentration of less approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range encompassed by any two of the foregoing values; or any combination of the foregoing values; wherein it is understood that TREE comprises at least six of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutium, scandium, and citrium. In a further aspect, the PLS composition comprises TREE present at a concentration of at least approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, 16 approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range encompassed by any two of the above values; or any combination of the above values;where it is; ζ / αηηη / ζζηζ / Ε / γίΛΐ understands that TREE comprises at least seven of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In an additional aspect, the PLS composition comprises TREE present at a concentration of at least approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L,approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range encompassed by any two of the foregoing values; or any combination of the foregoing values; wherein it is understood that TREE comprises at least eight of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of at least approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, 15 approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range spanned by any two of the above values; or any set of the above values; wherein it is understood that TREE comprises at least nine of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In an additional aspect, the PLS composition comprises TREE present at a concentration of at least approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range spanning any two of the above values; or any combination of the above values; wherein it is understood that TREE comprises at least ten of the following elements: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of less approximately 10 mg / L, approximately 11 mg / L, approximately 12 mg / L, approximately 13 mg / L, approximately 14 mg / L, approximately 15 mg / L, approximately 16 mg / L, approximately 17 mg / L, approximately 18 mg / L, approximately 19 mg / L, approximately 20 mg / L, approximately 21 mg / L, approximately 22 mg / L, approximately 23 mg / L, approximately 24 mg / L, approximately 25 mg / L, approximately 26 mg / L, approximately 27 mg / L, approximately 28 mg / L, approximately 29 mg / L, approximately 30 mg / L, approximately 31 mg / L, approximately 32 mg / L, approximately 33 mg / L, approximately 34 mg / L, approximately 35 mg / L, approximately 36 mg / L, approximately 37 mg / L, approximately 38 mg / L, approximately 39 mg / L, approximately 40 mg / L, approximately 41 mg / L, approximately 42 mg / L, approximately 43 mg / L, approximately 44 mg / L, approximately 45 mg / L, 20 approximately 46 mg / L, approximately 47 mg / L, approximately 48 mg / L, approximately 49 mg / L, approximately 50 mg / L; or a range encompassed by any two of the above values; or any combination of the above values; wherein TREE is understood to comprise lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium. In an additional aspect, the composition of PLS ​​comprises three or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein said TREE comprises at least three of: lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium.In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein the TREE is understood to comprise at least four of lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein the TREE is understood to comprise at least five of lanthanum, cerium, praseodymium, neodymium, 20 ζ / αηηη / ζζηζ / Ε / γίΛΐ prometio, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, lithium, lithium, luteum and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein said TREE comprises at least six of lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein the TREE is understood to comprise at least seven of lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium.In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein said TREE comprises at least eight of lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein the TREE is understood to comprise at least nine of lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. In a further aspect, the PLS composition comprises TREE present at a concentration of ζ / αηηη / ζζηζ / Ε / γίΛΐ about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 5 mg / L, 5 mg / L to 5 mg / L 80 mg / L, 5 mg / L to 75 mg / L, 5 mg / L to 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 50 mg / L, a 5 mg / L, 45 mg / L mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein the TREE is understood to comprise at least ten lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium.In a further aspect, the PLS composition comprises TREE present at a concentration of about 5 mg / L to 100 mg / L, 5 mg / L to 95 mg / L, 5 mg / L to 85 mg / L, 5 mg / L to 80 mg / L, 5 mg / L to 75 mg / L, 75 mg / L, 70 mg / L, 5 mg / L to 65 mg / L, 5 mg / L to 60 mg / L, 5 mg / L to 55 mg / L, 5 mg / L to 50 mg / L, 5 mg / L to 45 mg / L, 5 mg / L to 40 mg / L; or a subinterval within any of the above intervals; or any set of values ​​with the above ranges; wherein the TREE is understood to comprise lanthanum, cerium, praseodymium, neodymium, prometium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium. In an additional aspect, the PLS composition comprises four or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. ζ / αηηη / ζζηζ / Ε / γίΛΐ In an additional aspect, the composition of PLS ​​comprises five or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. In an additional aspect, the composition of PLS ​​comprises six or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. In an additional aspect, the composition of PLS ​​comprises seven or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. In an additional aspect, the composition of PLS ​​comprises eight or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. In an additional aspect, the composition of PLS ​​comprises nine or more of the following materials in the indicated amounts: Se present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; Y present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; La present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; Ce present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; Pr present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; Nd present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; Sm present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; Eu present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gd present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tb present at a concentration of approximately 0.0.05 mg / L to approximately 1.5 mg / L; Dy present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Ho present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Er present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a subinterval within any of the above intervals; or one or more discrete values ​​within any of the above intervals. In an additional aspect, the composition of PLS ​​comprises ten or more of the following materials 25 ζ / αηηη / ζζηζ / E / γίΛΐ approximately 5 mg / L; Tm present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; Yb present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and Lu present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L; or a sub-range within any of the above ranges; or one or more discrete values ​​within any of the above ranges. In an additional aspect, the described composition of PLS ​​comprises Fe in a lower concentration than that present in the raw material of DAM.In yet another aspect, the described composition of PLS ​​comprises Fe in a concentration less than approximately 25 mg / L, approximately 24 mg / L, approximately 23 mg / L, approximately 20 mg / L, approximately 19 mg / L, approximately 18 mg / L, approximately 17 mg / L, approximately 16 mg / L, approximately 15 mg / L, approximately 14 mg / L, approximately 13 mg / L, approximately 12 mg / L, approximately 10 mg / L, approximately 9 mg / L, approximately 8 mg / L, approximately 7 mg / L, approximately 6 mg / L, approximately 5 mg / L; or a range having a lower limit essentially of approximately 0 mg / L to an upper limit being any of the above values; or a range having a lower limit essentially of approximately 5 mg / L to an upper limit being any of the above values; or a range having a lower limit essentially of approximately 7 mg / L.5 mg / L up to an upper limit which is any of the above values; or any combination of the above values. ζ / αηηη / ζζηζ / Ε / γίΛΐ In a further aspect, the described composition of PLS ​​comprises thorium and uranium present in a total concentration of less than approximately 10 mg / L, approximately 9 mg / L, approximately 8 mg / L, approximately 7 mg / L, approximately 6 mg / L, approximately 5 mg / L, approximately 4 mg / L, approximately 3 mg / L, approximately 2 mg / L, approximately 1 mg / L, approximately 0.9 mg / L, approximately 0.8 mg / L, approximately 0.7 mg / L, approximately 0.6 mg / L, approximately 0.5 mg / L, approximately 0.4 mg / L, approximately 0.3 mg / L, approximately 0.2 mg / L, approximately 0.1 mg / L; or a range encompassed by any two of the above values; or any combination of the above values. In an additional aspect, the described composition of PLS ​​comprises cobalt in an amount of approximately 1 mg / L to approximately 30 mg / L, from approximately 1 mg / L to approximately 25 mg / L, from approximately 1 mg / L to approximately 20 mg / L, approximately 1 mg / L to approximately 15 mg / L, approximately 5 mg / L to about 30 mg / L, about 5 mg / L to about 25 mg / L, about 5 mg / L to about 20 mg / L, about 5 mg / L to about 15 mg / L, about 10 mg / L to about 30 mg / L, about 10 mg / L to about 25 mg / L, about 10 mg / L to about 20 mg / L, about 10 mg / L to about 15 mg / L, approximately 15 mg / L to approximately 30 mg / L, approximately 15 mg / L to approximately 25 mg / L, approximately 15 mg / L to approximately 20 mg / L, approximately 20 mg / L to approximately 30 mg / L, approximately: 20 mg / L to ζ / αηηη / ζζηζ / E / γίΛΐ approximately 25 mg / L; or a subinterval within any of the above intervals; or a set of values ​​within any of the above intervals. In an additional aspect, the described composition of PLS ​​comprises approximately 50% to approximately 80% by weight of cobalt, approximately 55% to approximately 80% by weight of cobalt, approximately 60% to approximately 80% by weight of cobalt, approximately 65% ​​to approximately 80% by weight of cobalt, approximately 70% to approximately 80% by weight of cobalt, approximately 50% to approximately 85% by weight of cobalt, approximately 55% to approximately 85% by weight of cobalt, approximately 60% to approximately 85% by weight of cobalt, approximately 65% ​​to approximately 85% by weight of cobalt, approximately 70% to approximately 85% by weight of cobalt, approximately 50% to approximately 90% by weight of cobalt, approximately 55% to approximately 90% by weight of cobalt, approximately 55% to approximately 90% by weight of cobalt, approximately 50% to approximately 8 ...0% to approximately 80% by weight of cobalt, approximately 55% to approximately 80% by weight of cobalt, approximately 50% to approximately 80% by weight of cobalt, approximately 50% to approximately 80% by weight of cobalt, approximately 50% to approximately 80% by weight of cobalt, approximately 50% to approximately 80% by weight of cobalt, approximately 50% to approximately 80% by weight of cobalt, approximately 50% to approximately 80% by weight cobalt weight, approximately 60% to approximately 90% by weight of cobalt,approximately 65% ​​to approximately 90% by weight of cobalt, approximately 70% to approximately 90% by weight of cobalt; or any subinterval within the above intervals; or any set of values ​​within the above intervals. Process for an enriched loaded leaching solution from acid mine discharges. In one aspect, the present description relates to processes for providing a loaded leach solution (PLS) enriched in REE materials, wherein the feedstock for the process is an acid mine discharge (AMD) feedstock. In a further aspect, the PLS may be used, as described herein, in a solvent extraction process, or other suitable purification technology, as described herein, to obtain one or more REEs that are further purified or enriched. In an additional aspect, the processes described comprise the following steps: (1) transferring the unprocessed DAM feedstock to a separator; (2) aerating the feedstock and adding an effective amount of at least one base to the separator to raise the pH of the resulting mixture; (3) optionally adding an effective amount of one or more flocculants and / or coagulants; (4) separating the solid and aqueous phases and discarding the solids; (5) optionally, if scandium is recovered, transferring the aqueous phase from the preceding step to a separator and adding an effective amount of base to raise the pH of the resulting solution, followed by (5)(a) optionally adding an effective amount of coagulants and / or flocculants; and then (5)(b) separating the solid and aqueous phases and collecting the Se-enriched solid concentrate; (6) transferring the aqueous phase from step (4) or from the optional step (5) to a separator;(7) add an effective amount of at least one base to raise the pH of the resulting mixture; (8) optionally add an effective amount of one or more flocculants and / or coagulants; (9) discharge the effluent and collect the REE-enriched preconcentrate; (10) dehydrate the preconcentrate and transfer the dehydrated REE-enriched preconcentrate to a mixer; (11) add an effective amount of at least one acid to lower the pH of the resulting solution and, optionally, add an effective amount of one or more oxidizing agents; (12) optionally add an effective amount of one or more flocculants and / or coagulants; (13) transfer the resulting solution from the preceding step to a filtration apparatus, filter, and discard the residual solids retained by the filter; (14) transfer the filtrate solution resulting from the preceding step to a mixer;(15) adding an effective amount of at least one base to raise the pH of the resulting solution; (16) transferring the resulting solution to a filtration apparatus, filtering, and discarding the residual solids retained by the filter; and (17) the resulting loaded leach solution (PLS) can be stored. In a further aspect, the PLS can be used in a solvent extraction process, or other suitable purification technology, as described herein, to obtain one or more REEs that are further purified or enriched. Figure 23 shows a flow diagram of an illustrative process for producing a PLS as described herein. The plant includes means 700 for transferring the raw DAM to a separator and means 702 for adding base to raise the pH of the resulting solution from approximately 4 to approximately 4.5, as well as means 704 for adding flocculants if required and means 706 for separating the solid and aqueous phases and for discarding solids. If scandium recovery is to be carried out, an optional scandium recovery device 708 is incorporated at this stage. The scandium recovery device 708 includes means 710 for transferring the aqueous phase to a separator and means 712 for adding sufficient base to raise the pH of the resulting solution from approximately 4.5 to approximately 5, a medium 714 for adding optional flocculants and / or coagulants, and a medium 716 for separating the solid and aqueous phases and collecting a scandium-enriched solid concentrate. The material resulting from this stage or from the separation medium 706, if scandium recovery is not carried out, is transferred to separator 718. Medium 720 for adding base to separator 718 dispenses the base until the pH of the solution is approximately 8.0 to approximately 8.5, while medium 722 adds optional flocculants and / or coagulants, and a device 724 discharges the effluent for standard water treatment while collecting an REE-enriched pre-concentrate for further processing. The REE-enriched pre-concentrate is transferred to a mixer by means of mechanism 726 and means 728 for adding acid; the dispensed acid reduces the pH of the solution to approximately 0.7, while medium 730 adds optional flocculants. The acidified solution is transferred by device 732 to a filter, and residual solids are discarded. Medium 734 transfers the resulting solution to a mixer where a base dispensing medium 736 dispenses the base until the pH of the solution is approximately 2.8 to approximately 3.0. A device 738 then transfers the resulting solution to a filter, where residual solids are discarded. After this, the PLS is stored in storage media 740 until it is transferred to solvent extraction by transfer medium 742. Figure 24 shows a diagram of a plant that can produce a PLS according to the process in Figure 23 or another illustrative process as described herein. The raw DAM feedstock 800 is transferred to a first separator 810, wherein the separator is connected to a base storage unit 812 and a flocculant storage unit 814 that can dispense base and flocculant as required into the separator 810; the solids 816 that precipitate at this point include mainly iron and aluminum and are transferred for waste disposal or further processing as desired.If scandium recovery is carried out, the liquids from the first separator 810 are transferred to a second separator 820, which is also connected to a base storage unit 822 and a flocculant storage unit 824 that can dispense base and flocculant as required according to the process described herein. The scandium precipitates from the second separator 820 as a scandium-enriched solid concentrate 826, and the remaining material 30, which still contains significant REE, is passed to a third separator 830. If scandium is not recovered, the REE-containing material is passed directly from the first separator 810 to the third separator 830.The third separator 830 is connected to the base storage unit 832 and the flocculant storage unit 834, which can dispense base and flocculant as required into the third separator 830. The effluent from this process 838 is discharged from the system, and the REE-enriched solid pre-concentrate 836 produced by this process is transferred to a first mixer 840. The mixer is connected to an acid storage unit 842, which can dispense acid into the mixer 840 as required to control the pH of the solution, as described herein. The material passes from the mixer 840 to a first filter 850, where the leach residue 852 is separated from the liquid material. This liquid material is then transferred to a second mixer 860, which is connected to a base storage unit 862 that can dispense base into the mixer 860 as required.From the mixer 860 the liquids pass to a second filter 870 and the leaching residue 872 is discarded while the filtrate is transferred as PLS to the storage unit 880 for later use in solvent extraction procedures 882. In one respect, the usable feedstock in stage 1 may include unprocessed DAM. In another respect, the distribution of REE and major elements in 155 DAM sources in the North and Central Appalachian coal basins is provided in Table 2 below. Table 2: Distribution of REE and Main Elements in Appalachian DAM Sources. ζ / αηηη / ζζηζ / Ε / γίΛΐ REE (pg / L) CAPP DAM Mean Confidence Interval Number of Samples CEMean Ratio Se 3.12 1.12 49 0.36 Y 50.48 20.53 51 0.41 La 27.27 15.21 51 0.56 Ce 54.55 27.65 51 0.51 Pr 8.16 3.95 50 0.48 Nd 37.82 17.19 51 0.45 Sm 9.88 4.04 50 0.41 Eu 2.68 0.98 50 0.37 Gd 12.59 4.95 51 0.39 Tb 1.98 0.71 50 0.36 Dy 10.76 4.31 50 0.40 Ho 1.98 0.73 50 0.37 Er 5.08 2.09 50 0.41 REE (pg / L) CAPP DAM Mean Confidence Interval Number of Samples CI: Mean Ratio Tm 0.82 0.25 49 0.30 Yb 3.95 1.58 50 0.40 Lu 0.72 0.21 49 0.29 TREE 231.85 103.12 50 0.44 HREE 91.48 LREE 140.36 Median 6.62 3.02 50 0.40 Main Metal (mg / L) Influent pH 4.95 0.43 51 0.09 Al 13.23 5.21 51 0.39 Ca 169.84 27.19 51 0.16 Ee 19.06 13.09 51 0.69 Mg 126.06 26.86 51 0.21 Mn 10.93 3.37 51 0.31 Na 37.37 18.89 51 0.51 Si 11.06 2.27 51 0.21 C1 5.40 2.94 50 0.54 so4 1111.84 193.95 50 0.17 MMR 1504.77 293.78 51 3.19 Median 19.06 13.09 51 0.31 ζ / αηηη / ζζηζ / Ε / γίΛΐ Table 2 (continued). REE (pg / L) NAPP DAM Mean Confidence Interval Number of Samples CEMean Ratio Se 6.34 1.55 131 0.24 Y 80.54 23.92 134 0.30 La 21.09 6.69 134 0.32 Ce 63.15 19.09 134 0.30 Pr 9.79 2.81 133 0.29 Nd 45.84 13.15 134 0.29 Sm 13.25 3.57 133 0.27 Eu 3.78 1.02 131 0.27 Gd 18.54 5.17 134 0.28 Tb 3.13 0.83 132 0.26 Dy 16.94 4.79 133 0.28 Ho 3.28 0.89 132 0.27 Er 8.28 2.40 133 0.29 REE (pg / L) NAPP DAM Mean Confidence Interval Number of Samples CL Mean Ratio Tm 1.28 0.30 130 0.23 Yb 6.36 1.79 134 0.28 Lu 1.08 0.25 130 0.23 TREE 302.69 85.99 133 0.28 HREE 145.79 LREE 156.90 Median 9.03 2.60 133 0.28 Main Metal (mg / L) Influent pH 4.21 0.34 132 0.08 Al 22.98 4.82 134 0.21 Ca 176.68 22.57 134 0.13 Fe 61.05 22.15 134 0.36 Mg 75.34 10.71 134 0.14 Mn 9.43 2.42 134 0.26 Na 519.65 185.99 134 0.36 Si 14.23 1.64 134 0.12 C1 304.07 239.70 130 0.79 SO4 1704.43 337.54 130 0.20 MMT 2887.85 827.54 133 2.56 Median 75.34 22.15 134 0.21 ζ / αηηη / ζζηζ / Ε / γίΛΐ Additionally, raw materials with the composition ranges in Table 1 are suitable for the process described herein. While DAM can be used as a raw material for the process, other raw materials are also considered. Furthermore, the raw materials suitable for this description do not contain high levels of uranium, thorium, or other hazardous components. In one respect, the described process can use a DAM feedstock with a pH of less than 2 to less than approximately 5.5, or of approximately less than 2, 2.5, 3, 3.5, 4, 4.5, 5, or 5.5. In one respect, the pH of the feedstock is less than 3. In another respect, the pH of the feedstock is less than 2. A typical distribution of DAM REE concentrations as a function of pH can be seen in Figure 22. In one aspect, in step 2 as described above, an effective amount of at least one base is an amount sufficient to raise the pH of the resulting mixture from approximately 4 to approximately 4.5, or at least to approximately 4, 4.1, 4.2, 4.3, 4.4, or approximately 4.5, or a combination of any of the above values, or a range encompassing any of the above values. In another aspect, the base may be NaOH, KOH, ammonia or ammonium hydroxide, calcium granules, quicklime, lime slurry, or a combination thereof. In one aspect, the base is lime slurry. In an additional aspect, in stage 4 as described above, the discarded solids may comprise iron or aluminum and / or other gangue metals with similar chemical and physical properties. In one respect, if scandium is being recovered and step 5 of the described process is being carried out, when the base is added, the desired resulting pH can be from approximately 4.9 to approximately 5.1, or approximately 4.9, 5.0, or approximately 5.1, or a combination of any of the above values, or a range encompassing any of the above values. In another respect, the base can be NaOH, KOH, ammonia or an ammonium compound, calcium granules, quicklime, lime slurry, or a combination thereof. In one respect, the base is lime slurry. In one aspect, in step 7 as described above, an effective amount of at least one base is sufficient to raise the pH of the resulting mixture from approximately 8 to approximately 8.5, or at least to approximately 7.8, 7.9, 8, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, or approximately 8.7, or a combination of any of the above values, or a range encompassing any of the above values. In another aspect, the base may be NaOH, KOH, ammonia or ammonium hydroxide, calcium granules, quicklime, lime slurry, or a combination thereof. In one aspect, the base is lime slurry. In another aspect, a higher pH within the described range may aid in the recovery of additional cobalt. In one respect, at stage 11 as described above, the desired resulting pH is approximately 0.5 to approximately 3.2, or approximately 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, or approximately 3.2, or a combination of any of the above values, or a range encompassing any of the above values. In some respects, the pH at this stage may be selected based on economic considerations such as, for example, the selling price of the product versus the cost of the acid added at this stage. In another aspect, several acids are considered at this stage, including, but not limited to, sulfuric acid, nitric acid, hydrochloric acid, or combinations thereof. In one aspect, the acid is nitric acid. In another aspect, the acid is hydrochloric acid. In one additional aspect, the acid contact with the raw material, unprocessed raw material, or DAMp / DAMpe pre-concentrate takes place in a reactor that is open to the atmosphere. Furthermore, this step can be carried out at ambient temperature. In yet another aspect, prior to the addition of acid, the raw material, unprocessed raw material, or DAMp / DAMpe pre-concentrate can be contacted with water while being mixed to create a suspension. Finally, the suspension is mixed with acid in step 11 as previously described, with continuous mixing to dissolve the REE from the solid raw material. In one additional aspect, as previously indicated, step 11 may optionally include the addition of an oxidizing agent. In yet another aspect, step 11 includes the addition of an oxidizing agent, so this aspect is not optional. In yet another aspect, the oxidizing agent may be hydrogen peroxide. Without wishing to be bound to any particular theory, it is believed that the addition of an oxidizing agent may improve the efficiency of gangue metal separation from the REE in the aqueous phase. It is also believed, without wishing to be bound to any theory, that the reducing agent may precipitate iron and manganese hydroxides from the PLS. In one additional aspect, and without wishing to be bound to any theory, filtration at acidic pH in this step prevents the formation of aluminosilicate gels and / or emulsions.It is also believed, without wishing to be tied to any particular theory, that gels and emulsions can hinder subsequent stages of the process, from processing to completion, and can interfere with pumping and mixing. Furthermore, an effective amount of an oxidizing agent can be added based on the following equation: H2O2= Df(Fe + (2Mn)), where: • H2O2 = hydrogen peroxide (moles) • Df = design factor • Fe = total iron (moles) • Mn = total manganese (moles) such that Df has a value of approximately 1.05 to approximately 1.7, approximately 1.1 to approximately 1.6, approximately 1.2 to approximately 1.5; or a sub-interval within the above intervals; or a value or set of values ​​within any of the above intervals. In any of the above aspects, mixers at any stage requiring a mixer can be connected in sequence to assist in the transfer of the product from one mixer to the next. In some aspects, any of the above processes can be performed partially (i.e., not to completion) if cost reduction is desired. In an additional aspect, in stage 12, as described above, In one respect, in stage 13 as described above, the residual solids discarded at this stage may include a large proportion of silicon. In another respect, stage 13 essentially removes all silicon from the raw material. In yet another respect, a filter or other separation mechanism, such as a plate and frame filter press, may be used to separate solids from the liquid. In a further respect, the solids are retained in the filter or filter press, which is then cleaned and can be reused. In some respects, the filter component may be made of or lined with polypropylene fabric. In another respect, in step 15 as described above, the desired pH of the resulting solution may be from approximately 2.8 to approximately 3, or it may be approximately 2.8, 2.85, 2.9, 2.95, or approximately 3, or a combination of any of the above values, or a range encompassing any of the above values. In some respects, when HCl is used as the acid in step 13, MgO may be a suitable base for use in step 15. In other respects, other bases may be used, including, but not limited to, NaOH, KOH, ammonia or ammonium hydroxide, calcium granules, quicklime, lime slurry, or a combination thereof. In one respect, the base is NaOH. In one aspect, in stage 16 as described herein, the discarded residual solids typically include iron. In another aspect, stage 13 essentially removes all iron from the raw material. In yet another aspect, a filter or other separation mechanism, such as a filter press or a plate and frame filter press, may be used to separate solids from the liquid. In another aspect, the solids are retained in the filter or filter press, which is then cleaned and may be reused. In some aspects, the filter component may be made of or lined with polypropylene fabric. In some aspects, an oxidizing agent may optionally be used in stage 13 to convert ferrous iron to ferric iron, which, without wishing to be tied to any theory, may aid in the precipitation of iron compounds. In yet another aspect, the oxidizing compound may be hydrogen peroxide or another chemical oxidizer.Alternatively, mechanical or electrochemical oxidation can be used. A flow diagram of the described process can be seen in Figure 23. A graphical representation of the described process, including an optional scandium collection (step 5), can be seen in Figure 24. In an additional aspect, the process described herein can be implemented in a mobile or commercial-scale plant as described herein as follows. Upstream Concentrator. Construction of Large-Scale Units. In one aspect, this description outlines a large-scale DAM treatment plant with an integrated REE / CM recovery operation. In another aspect, possible alterations to the treatment plant may include, but are not limited to: (1) staged precipitation using multiple clarifiers / thickeners in series; (2) independent pH control at each clarifier; and (3) additional material handling and filtration units to recover and dewater the REE-enriched concentrates. In addition, to enhance the traditional DAM treatment system, this document describes a state-of-the-art control and automation system for remote monitoring of key operating parameters. Furthermore, this package can provide real-time measurements of pump and mixer motor conditions, pH levels, selected ion concentrations, and other variables. Finally, these values ​​can be recorded in a data file format and used to control the feedback loop. In one respect, all parts of the process described herein can be carried out while adhering to all applicable local, state, and federal regulations. In another respect, once construction activities are complete, a safety analysis / review can be performed before commissioning and testing the equipment. Full-Scale Unit Operation. In one aspect, the following parameters are outlined in this description for the full-scale operation of an upstream concentrator as described herein: (1) the specific locations of sampling points within the system and the expected consistency of those samples (liquid, solid, or slurry); (2) the specific procedures for obtaining, handling, transporting, and storing various types of samples; (3) the expected frequency and extent of sample collection for both routine and intensive analyses; (4) the specific protocols for analyzing samples and interpreting the resulting data; and (5) the protocols for retaining and archiving samples. In one aspect, the test matrix described herein is designed to collect performance data under different operating conditions while ensuring that the final water discharge meets the permit requirements of the National Pollutant Discharge Elimination System (NPDES). In another aspect, the test matrix is ​​based on the results of the evaluation of small-scale units and incorporates expected variations in the DAM flow and REE concentration that follow seasonal variations throughout the calendar year. Furthermore, these natural variations can be monitored over time and used to assess the robustness and resilience of the REE / CM enrichment process. Additionally, after identifying and validating the optimal process operating parameters, the upstream concentrator will operate continuously in these configurations. The REE / CM pre-concentrates generated during this time will be collected in 55-gallon drums or geotextile super sacks and stored for future testing in the downstream processing units described. Acid leaching / Solvent extraction. Systems Design. In one aspect, this description outlines a system that processes the pre-concentrates generated from the upstream concentration unit on a large scale. In this aspect, the system includes, but is not limited to: (1) a balanced mass process flow diagram, (2) piping and instrumentation diagrams, (3) a proposed facility design, (4) a construction cost estimate based on supplier quotations, (5) an estimate of daily operating costs, and (6) final engineering drawings of the pilot-scale plant. In one respect, the pilot-scale installation is located adjacent to the upstream concentrator at the designated site. Furthermore, this location has adequate access to the water, power, and other utilities required for the pilot-scale system. In yet another respect, only minimal changes to the existing installation will be required before the system is commissioned. Acquisition, construction, and installation of the system. Site preparation may include removing unnecessary equipment, reinforcing foundations or structures, and / or adding mechanical and electrical services. These initial preparations also ensure that the installation and assembly of the equipment can be completed on time. Furthermore, the manufactured components and final equipment can be shipped directly to the designated site. System testing, training, and troubleshooting. In one respect, the primary safety hazard anticipated in this description is the use of strong acids in the leaching and solvent extraction units. At a minimum, acid-resistant gloves and lab coats should be worn, and adequate ventilation should be provided in the testing area to minimize risk to personnel, along with chemical safety and hygiene training in the laboratory. In one respect, a series of control tests will be conducted to identify and resolve operational problems that may arise during detailed system testing. In another respect, control tests can provide an opportunity to mitigate these problems while providing key operational data that can support a detailed testing campaign. In yet another respect, the specific objectives of this testing program include, but are not limited to: (1) verifying the supplier's specifications regarding capacity and power; (2) ensuring the adequacy of various auxiliary equipment and services; and (3) identifying the operational limits to be used in detailed system testing.Furthermore, control tests can be performed by running all unit operations under "water-only" conditions to first ensure the structural integrity of the process units. Additionally, after the water-only test, solids can be slowly introduced into the test regime to verify the suitability of valves, pumps, and other fittings. Finally, strong acids and other chemicals can be added only after the system has been tested under these more benign conditions. In one aspect, this description outlines a state-of-the-art real-time control and monitoring system capable of providing real-time measurements of pump and mixer motor conditions, pH levels, selected ion concentrations, and other variables. In another aspect, these values ​​can be recorded in a data file format and used to control the feedback loop. In yet another aspect, this task also encompasses all the troubleshooting necessary to ensure consistent and safe operation of the system at pilot scale. Parametric testing of the system. In one aspect, using raw materials produced from previous stages of the process described herein, acid leaching and solvent extraction tests can be performed over an extended operating period. In another aspect, each experimental condition may require at least 64 hours of continuous testing, and the solvent extraction (SX) operation is expected to run continuously for 24 hours a day. In yet another aspect, the specific elements to be analyzed during this testing campaign may include, but are not limited to: (1) the influence of the type and concentration of the SX extractant; (2) the influence of the type and ratio of SX solvent; (3) the influence of the type of acid and pH on extraction and separation; and (4) the number of extraction and separation stages required to achieve the target purity level.In another aspect, the present description provides ways to eliminate non-target impurities and optimize the process with respect to separation efficiency, solvent recycling, and waste minimization. In one aspect, a test matrix can be generated using a statistical design of experiments, and specific conditions can be blocked and repeated to assess experimental error while mitigating the influence of covariates, such as ambient conditions. In another aspect, the results of this experimental design can be analyzed using response surface methodology to identify the optimal conditions that lead to the highest recovery and selectivity. Testing of alternative raw materials. In one respect, after achieving the objectives using the preferred DAM feedstock, other feedstocks can be evaluated at the ALSX pilot plant. In another respect, specific examples include, but are not limited to, DAM treatment sludge, coal residues and underground clays, fly ash and gasification coal, other REE-enriched coal byproducts, and combinations thereof. Laboratory testing and support. In one respect, both aqueous and solid samples can be routinely analyzed for REE / CM, major gangue metals, trace gangue metals, and CM. In another respect, aqueous REE concentrations can be determined using inductively coupled plasma mass spectrometry (ICP-MS). In yet another respect, solid samples can be melt-digested with sodium peroxide (NaiCh) and redissolved in hydrochloric acid, and the resulting aqueous analysis can be performed using ICP-MS. In another respect, major ions such as iron (Fe) and aluminum (Al) will be determined using a suitable technique such as inductively coupled plasma optical emission spectrometry (ICP-OES). In another aspect, a broad exploration of raw materials can be used to identify other CMs and, if economically attractive, ensure that the described ALSX process is modified for their recovery. Analysis of economic systems. In one respect, the experimental results of the various test campaigns, as well as the results of the system design optimization model, can be compiled into a technical-economic analysis (TEA). Furthermore, in this respect, the analysis can report costs and performance at the existing scale and project those costs to the next scale of design and / or commercial implementation by using standard scaling factors and detailed costs as appropriate. In one respect, all analyses will use guidelines and assumptions provided by the 40 ζ / αηηη / ζζηζ / E / γίΛΐ National Energy Technology Laboratory (NETL), and the results will be presented in accordance with NI 43-101 reporting standards for mineral project descriptions. In any of these aspects, at a minimum, this analysis will include: a clear statement of assumptions; cash flow projections on an annual basis; a discussion of potential net present value (NPV) and internal rate of return (IRR); a summary of the imposed tax structure; and a sensitivity analysis with respect to grade, price, and other important input factors. Environmental systems analysis. In one aspect, an environmental systems analysis can be conducted concurrently with other project activities and can focus on two specific objectives: material handling considerations and environmental compliance. In one aspect, the material handling design will address the dewatering, filtration, and short- and long-term material storage requirements for the upstream concentration process. In one aspect, the specific research tasks to be addressed for the material handling system design include, but are not limited to: 1. In one aspect, the following elements for the proposed GEOTUBE® geotextile woven bags for the first and second division have been explored at field scale: engineering permittivity and strength design, GEOTUBE® ratio sizing (length and diameter ratios), GEOTUBE® stacking configurations, and techniques to ensure safe and environmentally benign dewatering operations. 2. In another aspect, the treatment requirements of the process for the GEOTUBE® water filtration, the primary liquid containment, the design and arrangement of the liquid transport and the characterization of the geotechnical material will be determined, which consists of material tests to determine the physical, strength and permeability properties. 3. In another aspect, a series of numerical modeling activities can be carried out for the mathematical characterization of the drainage in the system and potential improvements. The results of the modeling are then compared and contrasted with laboratory tests and field results. 4. In yet another aspect, the process efficiency can be studied to identify and reduce barriers to the future commercialization of REE / CM technology. Furthermore, in this regard, a specific area for efficiency improvement is the dewatering of sediments from the raw materials of divisions 2 and 3, and the iron-rich sediment from division 1. In one aspect, by using hydrometallurgical methods in the process described at bank scale, we produce a concentrate with 80% rare earth oxides from DAM treatment sludge (Figure 9). In one aspect, we have evaluated the extraction of REE / CM from the precipitates of the DAM treatment and from untreated DAM. In another aspect, the unprocessed solids from the DAM treatment can be transported to a central acid leaching / solvent extraction (ALSX) facility for final processing into a high-quality mixed rare earth oxide (MREO). In an alternative aspect, a field concentrate can be extracted and dewatered upstream of a conventional DAM treatment plant and transported to the ALSX facility. In a further aspect, the process described herein can accept and produce a REE / CM concentrate from any source. Having now described the general aspects of this description, the following examples illustrate some additional aspects. While the aspects of this description are described in relation to the following examples and their corresponding text and figures, there is no intention to limit the scope of this description to this one. Rather, the intention is for it to cover all alternatives, modifications, and equivalents included within the spirit and scope of this description. REFERENCES The following references are cited in this description. Ref. 1. Stumm, W. and Morgan, JJ 1995. Aquatic Chemistry, Chemical Equilibria and Rates in Natural Waters, 3rd ed. Hoboken, NJ: John Wiley & Sons, Inc.: 1022 pp. Ref. 2. Kim, E and Osseo-Asare, K.2012. “Aqueous stability of thorium and rare earth metáis in monazite hydrometallurgy: Eh-pH diagrams for the Systems Th-, Ce-, La-, Nd-(PO4)-(SO4)-H2O at 25 °C,” Hydrometallurgy, 113-114:67-78. Ref. 3. Pourbaix, M., 1966. Atlas of electrochemical equilibrium in aqueous solution. Nueva York, NY :Pergamon. Ref. 4. Bourricaudy, Ernesto y otros. 2016. “Commissioning of a Mini SX Pilot Plant at SGS Minerals - Lakefield Site”. In: IMPC 2016: XXVIII International Mineral Processing Congress Procccdings. Qucbcc, Cañada: pp. 1-16. Ref. 5. Chiarizia, Renato and Alexandra Briand, 2007. “Third phase formation in the extraction of inorganic acids by TBP in n-Octane,” Solvent Extraction and Ion Exchange, 25:351-371. Ref. 6. Kedari, C S y otros, 2006. “Third Phase Formation in the Solvent Extraction System Ir (IV) ζ / αηηη / ζζηζ / Ε / γίΛΐ Cyanex 923,” Solvent Extraction and Ion Exchange, 23:545-559. Ref. 7. Koermer, Scott and Aaron Noble (2018). “Unpublished Solvent Extraction Research”. PhD thesis. Virginia Polytechnic University. Ref. 8. Ren, Panpan, 2019. “Recovery of Rare Earth Elements (REE) from Coal Mine Drainage Sludge Leachate,” PhD thesis. West Virginia University. Ref. 9. Ritcey, G.M., 1980. “Crud in solvent extraction processing - a review of causes and treatment,” Hydrometallurgy, 5:97-107. Ref. 10. Ritcey, G.M. and A.W. Ashbrook, 1979. Solvent Extraction Principies and Applications to Process Metallurgy Part II. Volume 1. Amsterdam: Elsevier Scientific Publishing. Ref. 11. Ritcey, G.M. y A. W. Ashbrook, 1984. Solvent extraction Principies and Applications to Process Metallurgy Part I. Volume 1. Amsterdam: Elsevier Scientific Publishing. Ref. 12. Takeno, Naoto, 2005. “Atlas of Eh-pH diagrams - Intercomparison of thermodynamic databases” Geological Survey of Japan, Tech. Rep. 419:1-287. Ref. 13. Wang, Weiwei, Yoko Pranolo and Chu Yong Cheng, 2013. “Recovery of scandium from synthetic red mud leach Solutions by solvent extraction with D2EHPA,” Separation and Purification Technology, 108: 96-102. EJEMPLOS The following examples are presented to provide those skilled in the art with a complete exposition and description of how the compounds, compositions, articles, devices, and / or methods claimed herein are made and evaluated. They are intended purely to illustrate the invention and are not intended to limit the scope of what the inventors consider to be their invention. Every effort has been made to ensure accuracy with respect to numbers (e.g., quantities, temperature, etc.), but some errors and deviations should be taken into account. Unless otherwise stated, parts are parts by weight, temperature is in °C or is at room temperature, and pressure is atmospheric or close to it. Example 1: Analytical Methods ICP-MS was performed using a Perkin Elmer Nexlon 2000-P instrument equipped with an Elemental Scientific S400V external autodiluent. Syngistic 2.4 software was used to collect and analyze data according to EPA 200.8 Rev. 5.4 (1994). The ICP-OES was performed on an Agilent Technologies ICP-OES 720 instrument using Expert II software in accordance with EPA method 200.7 Rev. 4.4 (1994). ζ / αηηη / ζζηζ / Ε / γίΛΐ A Gallery discrete analyzer system (CPQ-00096605 from Thermo Fisher Scientific) was used for some measurements, including pH. Data were collected and analyzed using Gallery 6.0.1 software in accordance with method SM 4500I 2011. Thermogravimetric analysis was performed using a LECO TGA 801 instrument with the Cornerstone software package version 2.8.8. The method used to determine moisture levels was developed internally with the sample taken from room temperature up to 105 °C and maintained until constant weight. Acid digestion is a manual technique using a nitric acid-to-sample ratio of 1:1. Additional data analysis was performed for all techniques using Microsoft Excel. Example 2: Laboratory-Scale Experiments and Process Considerations Laboratory experiments were conducted before scaling up the described process. Preliminary results yielded a solid raw material with an average REE / CM ratio of 2.88% in the laboratory (see Table 3) to 0.2% in an initial continuous field extraction test. Of that amount, 0.14% were mixed REE oxides (MREO), including the five REE that are also CM (0.07%) and the critical mineral cobalt (0.06%). Table 3: Enrichment of Unprocessed DAM Samples. ζ / αηηη / ζζηζ / Ε / γίΛΐ REE Site in Unprocessed DAM (pg / L) MREO Grade (%) Enrichment Factor AQ51 738 1.30 17,615 AQ2 352 2.08 59,091 AQ50 2119 2.20 10,382 AQ8 2353 3.16 13,430 AQ65 1300 5.65 43,439 Average 1372 2.88 28,791 A field trial of a mobile version of the plant described herein (see Figures 1A-1B) was implemented at a conventional DAM treatment plant referred to herein as the Omega Site. The pre-concentrate from that plant (MREO = 0.2%), when processed through ALSX, yielded a final MREO grade of 54.4% without acid washing (Figures 2A-2B). In some experiments, acid washing increased the MREO from 40% to 62% or 80% by reducing the residual fraction by approximately half. It is significant that the LREO and HREO were 35.3% and 64.7%, respectively, while the addition of CM to HREO yielded 64.7%. The described plant and process feature a staged precipitation / DAM treatment unit that concentrates REE away from the major gangue elements while simultaneously producing clean water for discharge. Significant efficiency and cost gains can be achieved by integrating DAM treatment with REE / CM recovery. Standard compliance-based DAM treatment raises the pH of the DAM from the inlet value (typically 2.5 to 3.5) to the final value required for discharge (7 to 8) in a single stage. This single-stage precipitation can significantly concentrate REE; however, it also captures several problematic gangue metals in the sludge byproduct. Previous work focusing on REE extraction from sludge has shown that these gangue metals contribute to high transportation costs, high acid consumption, and demanding separation processes. The current process focuses on raw DAM in the early stages of standard treatment and uses staged precipitation to isolate REE from other gangue elements. A simplified process scheme for performing this staged precipitation is shown in Figure 3. In this representation, staged precipitation is achieved using two reagent mixing units and three clarifiers. Two parallel clarifiers (A and B) receive DAM adjusted to the first pH setpoint provided by mixer A. This provides most of the DAM treatment capacity. The underflow from clarifiers A and B consists mainly of iron and aluminum oxyhydroxides and can be removed similarly to the byproducts of conventional DAM treatment, i.e., dewatering cells or GEOTUBE®.Mixer B raises the pH of clarifier A and the overhead stream B to precipitate the REE / CM for removal in clarifier C. At this point in the circuit, the solid product is largely free of harmful gangue metals and contains few acid-consuming constituents. The solids in the underflow of clarifier C are a pre-concentrate of REE / CM, which would be dewatered and fed to the ALSX plant for final concentration. Since the pH is raised to circumneutral values ​​in the final stage, the overhead stream from the third clarifier can be safely discharged into the environment in compliance with NPDES limits. Tests show that the described process can effectively concentrate REE / CM from raw DAM, with overall enrichment factors ranging from 13,000x to 15,000x. More importantly, the process has proven to be extremely robust, as tests using different water sources as feedstocks, representing a variety of geochemical environments, have consistently yielded similar results regarding the final REE purity. Further tests have evaluated the influence of raw water characteristics, alkali content, pH endpoint, redox potential, flocculant usage, and the number of process stages. ζ / αηηη / ζζηζ / Ε / γίΛΐ When properly optimized, these processes have consistently achieved a REE / CM recovery > 96% and generated products with REE / CM grade consistently between 0.1% and 5% by weight. The site-specific testing will focus on a single DAM source in continuous run mode, as described in the following examples. The upstream concentrator will be evaluated based on its ability to handle variations in DAM flow and concentration while meeting three parameters: NPDES permit compliance, operating costs, and the ability to supply the ALSX plant with appropriate grade feedstock (~0.1% to 5% MREO). The ALSX plant will be evaluated based on operating costs and product quality approaching or exceeding 35% to 95%. The added infrastructure includes an additional clarifier in series with the two clarifiers typically required in a DAM plant of this capacity. A separate lime doser and an additional material handler will also be needed to isolate the REE pre-concentrate.Since the initial and final pH points of this process are similar to those of conventional DAM treatment, the process is expected to add only modestly to base consumption. This result is particularly favorable given the high consumable costs for many REE concentration strategies. Table 4 illustrates the data analysis based on laboratory tests to identify pH adjustment points for the DAM / REE preconcentrator, based on batch laboratory tests. The recovery rate for precipitation indicates the extent to which the main gangue elements are rejected in the early stages of the process, while the REE is recovered to a very high degree (97%) in the final precipitate. This represents 48,015 mg REE / kg or 4.8%. Table 4: Laboratory Extraction Tests at 3 pH Adjustment Points. ζ / αηηη / ζζηζ / Ε / γίΛΐ Element Precipitate Concentration Precipitate Recovery (%) pH 4.0 pH 5.0 pH 8.0 Total pH 4.0 pH 5.0 pH 8.0 Fe 373 600 2436 7253 383 289 97 1 2 Al 37 677 235 055 35 704 308 435 12 76 12 S 52 100 72 459 7107 131 666 4 55 5 Si 4 623 13 504 98 068 116 195 4 12 84 Zn 50 478 110 268 110 796 0 0 100 Mn 9 788 4181 63 521 77 491 13 5 82 Mg 397 616 32 540 33 552 1 2 97 Ca 1296 2387 9930 13 613 10 18 73 Co 48 35 8025 8108 1 0 99 Element Precipitate Concentration Precipitated Recovery (%) pH 4.0 pH 5.0 pH 8.0 Total pH4.0 pH 5.0 pH 8.0 Ni 108 109 5710 5927 2 2 96 Cd 20 0 138 158 12 0 87 Cl 0 11 95 106 0 11 89 Total 479 706 331 271 378 358 1 189 336 40 28 32 Se 18 59 18 95 19 62 19 Y 27 325 13 307 13 659 0 2 97 La 7 15 3597 3618 0 0 99 Ce 136 127 8950 9212 1 1 97 Pr 8 17 1786 1811 0 1 99 Nd 52 97 9019 9168 1 1 98 Sm 15 45 2386 2446 1 2 98 Eu 3 13 586 602 1 2 97 Gd 14 67 3473 3554 0 2 98 Tb 2 13 450 465 0 3 97 Dy 10 86 2286 2382 0 4 96 Ho 2 16 415 422 0 4 96 Er 5 48 1008 1061 0 5 95 Tim 1 8 116 124 1 6 93 Yb 5 49 541 594 1 8 91 Lu 1 7 80 88 1 8 91 TREE 305 991 48 015 49 311 1 2 97 Th 158.7 6.2 0.9 165.9 95.7 3.8 0.6 U 1.8 22.3 96.1 120.2 1.5 18.6 80.0 TAC* 160.5 28.6 97.1 286.1 97.2 22.3 80.5 ζ / αηηη / ζζηζ / Ε / γίΛΐ *Total Acts. The incremental lime dosing rates and costs for the upstream concentrator and the resulting resource, grade, and recovery are estimated at each pH adjustment point (Table 5). Based on two samples from an initial test site, this type of analysis can be used to quickly identify the most efficient pH adjustment points based on operating costs, grade, and recovery. This type of testing protocol and the knowledge gained during upstream concentrate sample processing through our ALSX plant will minimize the risk of scaling up as the DAM / REE is designed, installed, and operated. Table 5: Process Analysis: Two runs at the Omcga DAM plant using two pH set points. Parameter Run 1 Raw DAM Setpoint Run 2 Raw DAM pH Setpoint of IpH 4.0 8.0 4.0 8.0 Acidity 302 116 30 461 53 46 Q (gpm) 500 500 500 500 500 500 Acid Load (lb / day) 1813 698 178 2765 316 275 TMM (mg / L) 74 45 16 115 42 39 TREE (pg / L) 841 824 23 1319 1006 64 Acid Load (tpd) 1813 698 178 2764 316 275 Lime Dosage Ratio (lb / day) 1495 576 147 2279 261 227 Cost of Lime ($ / day) $149.48 $57.58 $14.67 $227.5 $26.06 $22.68 % Total Cost of Lime 67% 26% 7% 82% 9% 8% TREE Grade (mg / kg) 102.8 102.8 5681.8 991 48,015 TREE Recovery 5.21% 91.63% 30.92% 65.41% ζ / αηηη / ζζηζ / Ε / γίΛΐ The processes described involve a solvent extraction / acid leaching process that can further enrich REE preconcentrates to commercially attractive purity levels. A bench-scale solvent extraction system has been designed to extract REE from DAM precipitates and concentrate them into a final REO product. The Rare Earth Extraction Facility (REEF) on the West Virginia University (WVU) campus contains an acid leaching circuit, 100 mixer-settler units, and downstream precipitation tanks. The system also incorporates state-of-the-art sensors and controls provided by Rockwell Automation (Figures 4A-4B). Bench-scale testing allowed for addressing problems before full site scaling. Given the distribution and concentration of metals in typical DAM-based leachates, slag formation has proven to be a significant concern in SX operation. The gangue element concentration was carefully monitored during testing, and leaching conditions were adjusted as needed. Figure 5 illustrates SX operation with and without slag formation. Data collected at this test facility have demonstrated the technical feasibility of concentrating REEs from DAM-based feedstocks. Previous test campaigns investigated the influence of several operating variables, including leaching pH, extractant concentration, organic-to-aqueous ratios, acid type and concentration for separation, precipitation conditions, and system feed flow rates. From these tests, optimal operating conditions were identified, and the process was validated using three sources of solids-treated DAM runs. These sources included the Omega, DLM, and Royal Scott DAM treatment plants operated by the West Virginia Department of Environmental Protection (WVDEP). The resulting MREO concentrations ranged from 62 to 80%. The pre-concentrate from the upstream concentrator can be conveyed to an adjacent pilot-scale ALSX plant for final concentration of the high-quality MREO product. This approach includes several key modifications to the existing ALSX facility. First, these efforts represent an increase in the scale of the project. The existing plant has a maximum production rate of 3 g / h, and the pilot-scale plant is expected to yield approximately 15.5 g MREO / h. Second, the solid feedstock for the ALSX system will be modified, with the pilot-scale ALSX being fed with a pre-concentrate feedstock from which most of the gangue metals have been removed. This modification has improved the overall performance of ALSX; previous laboratory-scale tests on pre-concentrates from the staged precipitation process have shown that a 54% MREO product can be generated from a single stage of solvent extraction (Figures 2A-2B).The existing bench-scale REEF on the WVU campus has been used to run offline tests to optimize the A34 feedstock configuration (a site selected as the source). In addition, the REEF facility has been used for further element-based separations, such as those optimized for cobalt and scandium recovery. The described DAM / REE process installation can be based on two critical process technologies: 1) upstream concentration and 2) acid leaching / solvent extraction. A block flow diagram showing the individual stages associated with each process is shown in Figure 6. None of the components of the described process have ever been integrated to extract REE from DAM-based feedstocks in a commercial setting. The upstream concentration unit has matured to a Technology Readiness Level (TRL) of 7 (full-scale system demonstration), while the ALSX has matured to a TRL of 6 (pilot-scale demonstration). The upstream concentration unit has been designed and operated as a scaled-down version of the DAM treatment plant to be implemented at the designated site. This scaled-down unit has also been used to evaluate and optimize operating parameters. The pilot-scale ALSX unit has been designed to be approximately 1 / 20 the size of a full-scale unit. The technical criteria that define the project's success are shown in Table 6. These values ​​represent the targets required for a commercial installation. To be competitive with other commercial REE resources (excluding scandium or other CMs), overall production costs must be in the range of $50 to $75 / kg of REE produced. The target yield requirements defined in this table represent a combination expected to achieve this cost target. Table 6: Yield Targets. ζ / αηηη / ζζηζ / Ε / γίΛΐ Performance Attribute Commercial Target Performance Requirement REE Recovery in Leaching Stage > 80% REE Recovery in SX Extraction Stage > 90% REE Loss in Washing Stage < 10% REE Recovery in SX Separation Stage > 85% REE Pre-Concentrate Trade > 0.5% Final Product Grade MREO > 90% Actinide Component of Rare Earth Intermediate Products < 1% of TREE Content Reagent Consumption in Acid Leaching < 100 kg / t of Feed Solvent Loss in Solvent Extraction < 200 ppm Recycled Raffinate > 25% Example 3: Upstream Mobile Concentration Unit A flow diagram of the mobile concentration plant constructed upstream is shown in Figure 10. Two circuits can be run in series or in parallel according to the described design. In some experiments, a three-stage precipitation scheme was employed using an on-site treatment clarifier, as well as two circuits in the mobile plant; this configuration is shown by a dotted line in the flow diagram. In other experiments, the two mobile circuits were run in parallel to maximize precipitate production using a two-stage precipitation procedure. After installation, control tests were conducted to train the pH controllers to maintain a constant level in the two tanks. A mobile unit, as shown in Figure 10, was connected to the system at the Omega DAM treatment plant. This allowed for the separation of clarified water for extraction from the system's clarifier before discharge into the settling or finishing ponds. A supplemental chemical treatment was also installed to enable the Omega clarifier to operate at lower pH levels while maintaining compliance with the National Pollutant Discharge Elimination System at the end of the finishing pond. The elemental analysis of the upstream concentration unit products is shown in Table 7. Table 7: Results of the Upstream Concentration Operation Unit. Analyte Mobile Plant Aqueous Feed Omega Mobile Plant Precipitated Product pH 4.35 8 Main Ions mg / L mg / kg Al 27.95 190 382.11 Ca 354.09 21 825.29 Co 0.15 515.65 Fe 2.51 16 990.35 Mg 28.19 3107.08 Mn 0.90 2630.15 Si 18.17 79 936.27 SO4 1135.21 1374.75 TMM 1567.15 316 761.63 Rare Earth Elements pg / L mg / kg Se 9.48 66.37 Y 46.15 318.64 La 8.26 61.04 Ce 27.41 206.32 Pr 4.33 31.84 Nd 21.66 154.70 Sm 6.27 45.87 Eu 1.62 12.21 Gd 9.65 71.68 Tb 1.72 12.83 Dy 10.54 77.10 Ho 2.04 14.89 Er 5.57 40.83 Tm 0.73 5.59 Yb 4.25 31.73 Lu 0.63 4.83 TREE 160.32 1156.45 Grade 0.000016 % 0.12% Actinides pg / L mg / kg Th 0.14 1.69 U 2.33 12.16 ζ / αηηη / ζζηζ / Ε / γίΛΐ Example 4: Bench Scale ALSX Plant Operation Overview of the Process An ALSX plant was constructed to recover REE from DAM precipitates. The plant design was based on extensive laboratory-scale studies of acid leaching and solvent extraction. An initial system closely resembling the proposed design was tested, and 51 control tests were conducted on each plant module to identify any construction or design flaws, ranging from minor leaks to inadequate component specifications. Following testing, modifications to the overall process were implemented to overcome any identified issues. After control testing and plant modifications, the ALSX plant was commissioned using a decoupled semi-continuous process. The bench-scale system comprises three operating units: an acid leaching and filtration module, a solvent extraction module, and a precipitation module. Initially, small batches (~60 L) of DAM precipitate (DAMp) were converted into loaded leaching solution (PLS) using the acid leaching portion of the plant. As the acid leaching technique was refined, larger batches were produced, supplying feedstock to the solvent extraction (SX) module for weekly runs. The SX process was scheduled to operate in eight-hour shifts, five days a week, until the PLS was depleted. Once the SX plant operation was complete, the separated aqueous product was processed using a precipitation module to convert the REE cations into oxalates. The REE oxalate solids were then calcined to transform the oxalates into oxides. After calcination, multiple washing stages were required to separate the REE from the gangue elements, thus increasing the quality of the final product. As a result of these procedures, 62% rare earth mixed oxide material was acquired from the ALSX plant. Raw Material Acquisition and Material Handling DAMp was collected from the proposed raw material sites for processing at the ALSX bench-scale plant. Ten 55-gallon drums of DAMp were collected from each of the three DAM sites evaluated for this research. A small excavator was used to remove the DAMp from the storage ponds on-site. Plastic liners were used to isolate the DAMp from the inside of the steel drums. Once delivered to the facility, the drums were stored in a controlled environment until the material was required for the leaching tests. The drums were placed on pallets at the time of loading. Once at the ALSX facility, a pallet jack was used to maneuver the drums into the storage area. When required for leaching, the drums were maneuvered using an overhead crane and a drum tilting hoist.This configuration was used to hoist the drums up to the acid leaching module 52 ζ / αηηη / ζζηζ / E / γίΛΐ where the DAMp was extracted from the lined drum and placed into five-gallon buckets. Each bucket was individually weighed to record the mass of DAMp before it was used in the acid leaching process. Acid Leaching Module The acid leaching module is located adjacent to the solvent extraction system. Figure 11 shows the constructed area for acid leaching operations. The leaching vessels were operated under a full-size fume hood to prevent operator exposure to acid fumes. The main components of the module include the fume hood, two 75-gallon stirred leaching mixing vessels, a 420 mm filter press with a 2.0 cubic foot capacity, air diaphragm pumps, and an acid dosing system. Directly outside the fume hood, a scale holds a drum of 68% nitric acid. The scale is used to monitor the quantities of chemicals and raw materials consumed in the leaching process. Acid Leaching Control Test During the ALSX system control tests, several operational difficulties were encountered when using the ALSX system as initially designed. As a result, modifications to the acid leaching flow diagram were required to address these issues. The main operational challenges encountered and the flow diagram modifications implemented to overcome these unforeseen complications are presented below. PLS Gel Formation During the control test, several batches of PLS ​​formed a gelatinous mixture when the pH was raised above the leaching pH set point. This problem was observed in the raw material from all three DAM sites. Figure 12 shows a representative sample of the gelatinous PLS after pH adjustment. The formation of this gel inhibited the pumping of the PLS. Additionally, the gel prevented filtration of the PLS; therefore, the separation of the solid and aqueous components of the leaching slurry was impractical. To alleviate this problem, several laboratory-scale experiments were conducted to address the issue of gel formation. During testing, it was discovered that PLS did not form a gel when an additional filtration step was included in the procedure. This additional filtration stage was introduced immediately after the PLS was reduced to a leaching pH value of 0.7. When tested in the acid leaching module, the additional filtration stage prevented the PLS from freezing at pH values ​​below 4.0. As a result, this additional filtration stage was implemented in the operating procedure. Filtration Even in the absence of PLS ​​gel formation, the vacuum tray filter failed to filter the PLS because it lacked sufficient filtration area for the amount of solid material remaining after acid leaching. This issue was not addressed during the design phase because the small-scale test apparatus used did not allow for a proper evaluation of the filtration. For example, leaching tests were performed using vacuum filtration with a Buchner funnel and filter paper. This operating condition did not produce a significant amount of precipitate to assess the bed depth and, therefore, the filtration area required for efficient solid-liquid separation. To mitigate this problem, a bench-scale plate and frame filter press was used to efficiently filter the PLS. Several batches of PLS ​​were created using the three different feedstocks. Testing indicated that the filter press was capable of filtering PLS solutions from all feedstocks at multiple pH values. The results of this experiment indicated that a 2-cubic-foot filter press had sufficient capacity to adequately filter PLS from a 75-gallon stirred leaching tank and create clarified PLS. Figures 13A–13B show a 150 mm laboratory-scale press used during testing and a 420 mm filter press that later replaced the pan filter. The large-scale trial with the 2 ft³ filter press was successful with all three raw materials as a direct result of the increased filtration area. Originally, the tray filter had a usable filtration area of ​​25 ft². The new filtration unit increased the filtration area by a factor of almost 1.75 to 43 ft². A Sandpiper S07 air diaphragm pump with a maximum capacity of 23 gpm was used to feed the filter press. The pump was supplied with polyvinylidene fluoride (PVDF) internal components to resist corrosion when pumping acidic liquids. The filter cake obtained from the filter press reached moisture values ​​of approximately 60%, which was substantially better than previous filter cakes obtained by vacuum filtration. Figures 14A-14B show the PLS filtrate and the residual solids remaining after the filter press operation. Acid Leaching Procedure and Results After modifying the acid leaching process and equipment, an updated process flow diagram was created, as shown in Figure 15. The PLS created for the baseline Royal Scot solvent extraction test was prepared in two batches. First, DAMp was added to the stirred leaching vessel in a cuvette to record the DAMp mass. A sample of DAMp was then collected from each cuvette and combined to form a representative overall DAMp sample. This sample was then analyzed using thermogravimetric moisture analysis, ICP-MS for REE, and inductively coupled plasma optical emission spectrometry (ICP-OES) for principal ion determinations. Second, water was added to the leaching vessel at 0.75 L per kg of DAMp as received. This value was determined empirically during control tests to facilitate mixing, pumping, and filtration of the PLS.Initial tests showed that using only DAMp and acid resulted in a thick slurry that could not be pumped and therefore could not undergo the filtration process. Third, with rapid stirring, 68% nitric acid was pumped into the leaching chamber until the desired leaching pH set point of 0.7 was reached. The pH was monitored using a portable pH meter that was calibrated before the start of each batch. This process took several hours for the vessel to reach pH equilibrium. Finally, the low-pH PLS was filtered using a 420 mm filter press. After filtration, the clean PLS was pumped into a leaching vessel. The pH of the PLS was then adjusted upwards with 50% sodium hydroxide to a pH of 3.0 to remove gangue metals. This process was repeated in stages over several hours until equilibrium was reached at the desired pH setting point. Finally, the PLS was filtered again to remove any solids that precipitated during the pH adjustment. The filtrate from this process was sampled and then transferred to the SX module as feed for liquid-liquid extraction. Table 8 shows the reagents and conditions implemented to create the Royal Scot PLS. Combined, the two batches yielded a total of 282 liters of PLS ​​for the subsequent SX process. The total acid consumption of the leaching procedure was 1.24 g of acid / g of feed. While the acid consumption of this batch process is high, other processes could be employed to reduce this metric. For example, countercurrent leaching could be used to achieve more efficient use of the acid leaching process. Table 8: Royal Scot Acid Leaching Parameters Used to Create PLS. ζ / αηηη / ζζηζ / Ε / γίΛΐ Parameter Batch 1 Batch 2 Total Wet Mass DAMp (kg) 103.51 103.96 207.47 Dry Mass DAMp (kg) 12.45 12.54 24.96 Water Volume (L) 75.60 75.60 151.20 Initial pH 8.57 8.37 16.94 Acid Type 68% HNO3 68% HNO3 68% HNO3 Added Acid (kg) 24.07 21.32 45.39 Leaching pH 0.59 0.75 0.67 Caustic Type 50% NaOH 50% NaOH 50% NaOH Added Caustic (kg) 8.71 8.44 17.15 Final pH 2.90 3.10 3.00 Final PLS Volume (L) 149.31 132.30 281.61 Filter Cake Wet Mass (kg) 33.75 36.02 69.76 Filter Cake Dry Mass (kg) 10.38 10.06 20.44 Acid Consumption (g of acid / g of ore) 1.31 1.16 1.24 ζ / αηηη / ζζηζ / Ε / γίΛΐ Analytical tests were performed on the feed, concentrate, and tailings from the integrated leaching process. These samples were analyzed using ICP-MS and ICP-OES methods to determine REE and major ion concentrations, respectively. Tables 9A and 9B show the results of the analytical tests as well as the mass balance for both leaching batches. Table 9A: Royal Scot Acid Leaching Test and Mass Balance (Batch 1). Analyte Sludge Assay Sludge Mass PLS Feed PLS Mass Recovery Main Ions mg / kg g mg / L g % Al 83 066.8 1034.4 2785.7 415.9 40% Ca 13 986.9 174.2 734.7 109.7 63% Co 697.2 8.7 21.1 3.2 36% Fe 124 032.3 1544.5 4.0 0.6 0% Mg 57 207.9 712.4 2342.1 349.7 49% Mn 19 445.6 242.1 707.8 105.7 44% Si 29 ​​654.3 369.3 62.1 9.3 3 % SO4 8942.0 111.3 940.0 140.4 100% C1 39.8 0.5 4.7 0.7 100 % TMM 337 072.8 4197.3 7602.1 1135.1 27 % Table 9A (continued). Analyte Assay Sludge Sludge Mass PLS Feed PLS Mass Recovery Rare Earth Elements mg / kg mg pg / L mg % Se 13.1 163.6 143.3 21.4 13% Y 343.1 4272.2 14% 746.1 2201.7 52% La 67.9 845.8 3100.6 462.9 55% Ce 205.6 2560.0 8849.8 1321.4 52% Pr 34.7 432.3 1490.2 222.5 51% Nd 170.2 2119.5 7429.1 1109.2 52% Sm 58.2 725.0 2427.4 362.4 50% Eu 15.2 189.4 617.6 92.2 49% Gd 86.8 1081.0 3623.2 541.0 50% Tb 13.8 171.7 555.4 82.9 48 % Dy 75.0 933.8 3019.1 450.8 48 % Ho 13.4 167.0 535.0 79.9 48 % Er 35.2 438.3 1388.7 207.3 47 % Tm 4.4 54.5 175.0 26.1 48 % Yb 23.7 294.8 949.6 141.8 48% Lu 3.5 43.6 140.0 20.9 48 % TREE 1163.8 14 492.4 49 190.0 7344.6 51 % HREE 612.0 7620.5 25 275.4 3773.9 50% LREE 551.9 6872.0 23 914.6 3570.7 52% Table 9A (continued). Analyte Filter Cake Assay Filter Cake Mass Mass Balance Main Ions mg / kg gg Al 21 406.7 222.1 396.3 Ca 2004.2 20.8 43.7 Co 87.3 0.9 4.6 Fe 152 369.3 1581.2 - Mg 6645.2 69.0 293.7 Mn 5963.3 61.9 74.6 Si 25 952.8 269.3 90.7 SO4 1136.0 11.8 - Cl 76.4 0.8 - TMM 215 641.2 2237.8 903.6 Table 9A (continued). ζ / αηηη / ζζηζ / Ε / γίΛΐ Table 9B (continued). Analyte Sludge Assay Sludge Mass Feed PLS PLS Mass Recovery Rare Earth Elements mg / kg mg gg / L mg % Se 13.1 163.6 212.3 31.7 19% Water 343.1 4272.2 15 472.8 2310.2 54% La 67.9 845.8 3293.4 491.7 58% Ce 205.6 2560.0 9138.1 1364.4 53 % Pr 34.7 432.3 1555.4 232.2 54% Nd 170.2 2119.5 7766.7 1159.7 55 % . Sm 58.2 725.0 2490.3 371.8 51 % Eu 15.2 189.4 639.0 95.4 50% Gd 86.8 1081.0 3671.1 548.1 51 % Tb 13.8 171.7 572.7 85.5 50% . Dy 75.0 933.8 2964.6 442.6 47% Ho 13.4 167.0 540.8 80.8 48% Er 35.2 438.3 1384.5 206.7 47 % Tm 4.4 54.5 173.2 25.9 47% Yb 23.7 294.8 948.2 141.6 48% Lu 3.5 43.6 134.8 20.1 46% TREE 1163.8 14 492.4 50 957.8 7608.5 52% HREE 612.0 7620.5 26 074.8 3893.2 51 % LREE 551.9 6872.0 24 882.9 3715.3 54% . Table 9B (continued). ζ / αηηη / ζζηζ / Ε / γίΛΐ Analyte Filter Cake Assay Filter Cake Mass Mass Main Ions mg / kg gg Al 21 145.3 219.4 389.6 Ca 1833.8 19.0 39.0 Co 124.3 1.3 3.7 Fe 110 933.2 1151.2 392.9 Mg 5895.5 61.2 294.7 Mn 7201.1 74.7 38.7 Si 24 190.7 251.0 111.0 SO4 1369.6 14.2 - C1 91.9 LO - TMM 172 785.3 1793.0 1269.7 Table 9B (continued) Analyte Filter Cake Assay Filter Cake Mass Mass Rare Earth Elements mg / kg mg mg Se 11.6 120.8 11.1 Y 42.1 437.0 1525.0 La 8.6 89.5 264.5 Ce 28.0 290.5 905.1 Pr 4.7 48.7 151.4 Nd 23.9 248.0 711.8 Sm 7.9 82.1 271.1 Eu 2.0 20.7 73.3 Gd 11.0 114.1 418.8 Tb 1.8 19.1 67.2 Dy 9.8 101.4 389.7 Ho 1.8 18.6 67.7 Er 4.7 48.6 182.9 Tm 0.6 6.3 22.4 Yb 3.3 34.4 118.8 Lu 0.5 5.2 18.3 TREE 162.4 1684.9 5199.0 HREE 87.2 905.4 2821.9 LREE 75.1 779.6 2377.1 ζ / αηηη / ζζηζ / Ε / γίΛΐ The analytical results revealed several significant outcomes from the leaching process. Both leaching batches produced PLS with generally similar element concentrations. Overall, approximately 51% of the REE was recovered in the PLS solution, while only 27% of the other major ions were recovered, indicating significant rejection of the gangue material. Most notably, the pH adjustment procedure resulted in the removal of almost all the Fe from the PLS. This is significant because Fe can interfere with the subsequent SX process. Other gangue material also removed from the PLS included Al (40%), Ca (65%), Mg (50%), Mn (49%), and Si (3%). Additionally, with respect to the REE, individual recoveries generally decrease as the atomic number of the REE increases. The exception to this observation is Se, which has a much lower average recovery of 16%. The low recovery is not easily explained by standard thermodynamic considerations (e.g., Eh-pH diagrams), which indicate that Se should remain in solution at pH values ​​below 6. Furthermore, Se is also readily leached from other raw materials using mineral acids. As a result, the current interpretation of these results is that other constituents within PLS 60 were interfering with the Se, resulting in precipitation at pH values ​​below 3.0 and preventing the Se from transferring to an aqueous phase upon acid digestion. The overall mass balance of the acid leaching process indicated a large variation between the balance and the initial elemental masses of approximately 27% for the main ions and 37% for the rare earths. This discrepancy is quite large and suggests analytical errors resulting from the sampling process or existing deficiencies in the measurement and recording procedures. Furthermore, these types of mass balance errors have been consistent throughout the investigation when using a saturated DAMp feedstock. Previous investigations using thermogravimetric analysis to explore the residual moisture in the DAMp material after dehydration have indicated that some residual moisture may remain in the solid after traditional dewatering methods. Given the high moisture content of the feedstock, even a small change in moisture values ​​could have a significant impact on the overall mass balance of the system. Solvent extraction module For this research, a bench-scale solvent extraction system with 100 individual mixer-settlers was acquired. Figure 16 shows the design of the bench-scale system. The constructed system was identical to the design specifications developed during the planning phase of this research. The overall SX plant consists of ten individual stainless steel racks, with ten mixer-settlers attached to each rack, along with the required pumps and chemical storage tanks necessary for operation. Multiple control tests were performed on this system to empirically obtain a minimum set of operating parameters. Initially, a hydrostatic test was completed to identify any leaks in the system. Additionally, the operation of each unit was evaluated during the control tests using multiple parameters to establish the key operational adjustment points required to perform the necessary process. This was achieved by using PLS (Process Line Scale) of each raw material to test the extraction, washing, separation, and saponification circuits in batches until analytical tests showed that the circuit was performing satisfactorily.After the most promising parameters were identified, each raw material was processed using the bench-scale SX plant continuously to develop a baseline result from which parametric tests could identify the effect of changing individual SX parameters on the overall plant performance. Solvent Extraction Agitation Test Throughout the control testing, several issues were observed that inhibited bank-scale system operations. As each issue was discovered, changes were implemented in the system design to alleviate the deficiencies. Each operational challenge observed during this testing regime is described below. Slag Formation in the Third Phase During initial control tests, two of the raw materials (DLM and Omega) caused considerable formation of a third phase, as seen in Figure 17. This third phase, also called slag, is a stable emulsion that causes significant problems in the SX circuit. The slag found during this test began to form at the organic-aqueous interface and eventually occupied most of the volume in the mixer-settler. Before finalizing the flow diagram for the continuous SX process, a thorough investigation of the third phase formation is necessary. Problems encountered during initial testing included difficulties in obtaining mass balances, organic losses in aqueous streams, and complete blockages of the pipes connecting the mixer-settlers. Unfortunately, the generation of large quantities of slag makes parametric testing with these raw materials difficult, if not impossible, to complete. Multiple exploratory tests were conducted in an attempt to prevent slag formation in the mixing chamber. These tests included diluting the PLS, using the modifier tributyl phosphate, varying the extractant concentrations, and changing the organic-to-aqueous (O:A) extractant ratio. Slag was found to be caused by the gradual oxidation of ferrous ions to ferric ions during solvent extraction. It was also found that adding hydrogen peroxide as an oxidizing agent at approximately a 1:1 molar ratio with ferrous ion concentrations in the PLS allowed all the iron to precipitate as ferric hydroxide during PLS preparation. This eliminated slag formation during solvent extraction. When the PLS of the three raw materials was compared, as shown in Table 10, it was evident that the Fe and Ca content in the Royal Scot PLS was considerably lower than in the other two raw materials. The current hypothesis is that Fe or Ca will reach a limiting organic concentration (LOC) where the metal ions will begin to precipitate and create a nucleus that will allow slag formation. As a result, the Royal Scott PLS was used to demonstrate this technology, while the DLM and Omega raw materials underwent further leaching tests to remove excess gangue metals. Table 10: Comparison of PLS ​​of Three Raw Materials. ζ / αηηη / ζζηζ / Ε / γίΛΐ Raw Material DLM Omega Royal Scot Final pH 3.05 2.04 3.01 Main Ions (mg / L) Al 9480.84 3133.43 2982.86 Ca 1401.59 1372.56 761.02 Co 102.98 18.60 22.43 Fe 1936.00 71.43 3.18 Mg 6845.59 455.24 2426.65 Mn 3595.23 105.58 777.82 Na 47.55 12 699.48 11 493.42 Yes 1274.31 59.31 53.64 SO4 497.79 25.39 881.37 C1 17.92 5.65 4.67 TMM 25 199.80 17 946.67 19 407.05 Rare Earth Elements (pg / L) Se 2118.11 962.45 < 0.037 Y 83 061.09 7151.53 12 504.72 La 23 908.46 1477.79 2646.17 Ce 64 313.63 4906.65 7519.84 Pr 8198.92 782.96 1248.48 Nd 34 781.11 3688.07 6330.98 Sm 8890.67 1133.53 2087.38 Eu 2325.90 302.10 529.65 Gd 13 509.25 1820.15 3011.83 Tb 2239.51 339.07 450.90 Dy 13 712.70 2016.94 2493.89 Ho 2713.13 381.42 444.83 Er 7453.57 1063.41 1162.19 Tm 965.45 144.99 136.08 Yb 5506.71 824.88 801.98 Mon 793.23 125.05 104.29 Th 163.78 11.28 < 0.007 U 815.79 257.11 198.47 TREE 274 491.42 27 120.98 41 473.23 HREE 132 072.74 14 829.88 21 110.72 LREE 142 418.68 12 291.10 20 362.51 BELIEVE 136 120.30 13 497.71 22 310.15. Maintenance in the Mixing of Organic: Aqueous (O:A) Ratio Another operational difficulty encountered in the SX plant operation was maintaining a constant O:A ratio in the mixing chamber. This problem was not observed in SX unit operations with a 1:1 feed ratio. Conversely, unit operations requiring high or low O:A ratios often presented challenges in maintaining a constant O:A mixing ratio. Two potential causes were identified. First, over time, the Tygon piping used to recycle the aqueous phase in the settler back to the mixer can harden and prevent the roller clamp, which restricts flow in the recycle line, from functioning properly. The second problem is inherent in the roller clamp design. Often, the roller clamps could not provide the fine adjustment required to properly maintain the preferred O:A mixing range of 1.5:1 to 1:1.5, as recommended by the SX plant manufacturer. To alleviate this problem, in-line valves were installed in the recycle lines of SX processes requiring higher feed ratios than the recommended mixing range. Organic loss during saponification During the control trial, four unit operations were used (extraction, washing, separation, and saponification). During these trials, a large fraction of the organic phase was transferred to the saponification raffinate and was not recycled back to the organic tank. Further investigations indicated that an additional stage was needed to separate the organic and aqueous phases. As a result, Megon's Rare Earth circuit was referenced, and an additional circuit (acid washing) was implemented directly after the saponification stage. This additional stage greatly improved the recovery of organics to the organic recycling tank. While the addition of the acid wash circuit improved organic recovery to a level acceptable for bench-scale plant operations, further modifications may be necessary as plant scale increases. Organic loss represents a significant cost for industrial-scale SX operations. Consequently, the addition of a coalescing device or other chemical modifier should be evaluated as the technological readiness level (TRL) of this process increases. SX Procedure and Results To develop a baseline test prior to the parametric test, a batch of PLS ​​was processed on the SX system with an initial set of operating parameters. Table 11 shows the parameters used to establish this baseline test. The extractant, Elixore 205, is a highly refined, kerosene-like aliphatic diluent with a high flash point, low viscosity, and ultra-low aromatic content. This diluent was selected for three reasons. First, standard kerosene was used in some control tests; however, the kerosene emitted a strong odor that permeated the enclosed area. Second, a diluent specifically designed for solvent extraction was needed to minimize scale-up problems as the project's TRL increased.Third, previous phase separation tests showed a slight advantage in phase separation times with Elixore 205 compared to other total diluents. Table 11: Solvent Extraction Circuit Parameters for Reference Tests. ζ / αηηη / ζζηζ / Ε / γίΛΐ Parameter Value Organic Extraction Elixore 205 Extractant di-(2-ethylhexyl) phosphoric acid Extractant concentration (M) 0.5 Modifier tri-n-butyl phosphate Modifier concentration (v / v) 20% Organic:aqueous advance 1:1 Mixer speed (rpm) 856 Organic pumping rate (mL / min) 75 Aqueous pumping rate (mL / min) 75 Washing Reagent H2O Concentration (v / v) 100% Organic:aqueous ratio 1:1 Mixer speed (rpm) 856 Washing pumping rate (mL / min) 75 Separation Reagent HC1 Concentration (M) 6 Organic:aqueous ratio 10:1 Mixer speed (rpm) 856 Separation pumping rate (mL / min) 7.5 Saponification Reagent NH4OH Concentration 2 Organic:aqueous ratio 5:1 Mixer speed (rpm) 856 Pumping for saponification (mL / min) 15 Parameter Value Acid Wash Reagent HNO3 Concentration (M) 0.75 Organic: Aqueous Ratio 1:1 Mixer Speed ​​(rpm) 856 Acid Wash Pumping Rate (mL / min) 75 ζ / αηηη / ζζηζ / Ε / γίΛΐ Di-(2-ethylhexyl)phosphoric acid (D2EHPA) was then selected as the primary extractant based on its widespread industrial acceptance. Initial control tests indicated the formation of a third slag phase in the extraction, washing, and separation circuits. To address this issue, tributyl phosphate (TBP) was added as a modifier. The extraction advance and wash O:A ratios were both set at 1:1 to provide equal transfer of REE and gangue metals to the organic phase and wash raffinate, respectively. For the separation circuit, an O:A ratio of 10:1 was used to concentrate the REE in the separation raffinate while minimizing the raffinate volume. This was advantageous for the downstream process, as the smaller volumes required less material handling. Finally, the saponification and acid wash O:A ratios were 5:1 and 1:1, respectively, based on the results of previous control tests. Mixer speeds were 856 rpm for each mixer in the SX plant. Lastly, each SX process was carried out using five mixer-settlers, with the exception of the acid wash stage, where only three mixer-settlers were used.This quantity exceeds the number of stages identified in the exploratory tests; however, using additional stages reduces the effects of other system inefficiencies that may occur during testing. During parametric testing, unit-by-unit sampling will subsequently identify the critical number of stages required. The plant was operated for eight days, with a total operating time of 58 hours. This equates to approximately 7.2 hours of operation per day, or 90% operational availability. During this time, 281 liters of PLS ​​feedstock were processed through the system and concentrated into 28.3 liters of separate raffinate. Additionally, the organic phase was continuously recycled back to the extraction stage. This demonstrated the process's ability to operate continuously, while also showing that no metal ions remained bound to the extractant; therefore, the extraction rate in the first circuit was reduced. An aqueous sample was obtained at the end of each day of operation to evaluate system performance. Figure 18 shows the process flow diagram of the ALSX system at the time of testing. As discussed previously, the aqueous and organic phases are circulated in countercurrent mode. Additionally, the organic phase advanced through each stage and was recycled for reuse at the end of the processing stream, after the saponification and acid washing stages. In the extraction stage, the PLS and organic phases are mixed and settled, transferring the REEs to the organic phase. Next, washing removes unwanted elements from the organic phase while leaving the REEs in the organic phase using water or a mild acid. In the separation stage, 6M HCl was used to remove the REEs from the organic phase. A high advance ratio was used in this stage to concentrate the REEs in the separated aqueous raffinate. The separated raffinate also contained the valuable product of this operation, which was used in the next module of the plant to recover the REEs. The final two stages, saponification and acid washing, were used to regenerate the extractant, cleaning the cation exchange sites on each D2EHPA molecule. Tables 12A and 12B below show the results of the daily analytical tests performed on the refined PLS. While there was no significant change in gangue material concentrations during the test period, the system took several days to reach a steady state with respect to the constant extraction of REEs. During the first three days, several of the LREEs were not fully extracted. This could be a function of the pH within the mixing cell not reaching equilibrium. In contrast, the HREEs approached steady-state extraction by day 2. Table 12A: Refining Extraction Stage, Main Metals. (Site: Royal Scot, units mg / L) ζ / αηηη / ζζηζ / Ε / γίΛΐ Day 1 2 3 4 5 Al 2646.6 3377.2 3258.0 3264.2 3408.3 Ca 858.5 847.2 783.5 850.9 753.0 Co 25.6 25.8 25.2 25.8 25.9 Fe 8.7 4.5 2.6 3.6 1.2 Mg 2639.8 2748.0 2707.7 2767.7 2790.3 Mn 854.0 876.1 847.1 880.3 883.8 Na 12 474.2 11 879.7 11 011.9 11 321.0 13 388.0 Yes 63.7 63.6 61.2 62.4 62.5 Total Main Metals 19,571.0 19,822.1 18,697.2 19,176.0 21,313.0 Table 12A (continued). Day 6 7 8 Al 3381.4 3313.2 3272.0 Ca 737.6 674.1 657.1 Co 25.8 25.5 26.1 Fe LO 0.9 0.8 Mg 2773.8 2732.8 2792.9 Mn 877.0 855.0 859.0 Na 12 206.8 11 957.5 11 684.6 Si 62.2 61.6 63.2 Total Main Metals 20 065.5 19 620.6 19 355.6 ζ / αηηη / ζζηζ / Ε / γίΛΐ Table 12B: Refining Extraction Stage, REE. (Site: Royal Scot, units mg / L) Day 1 2 3 4 5 6 7 8 Se < 0.037 < 0.037 < 0.037 < 0.037 0.3 0.6 0.5 < 0.037 Y 1435.3 529.4 221.3 66.3 77.6 21.4 41.7 43.5 La 3950.7 1135.6 38.8 17.0 63.6 32.1 31.5 24.5 Ce 7594.7 836.6 61.2 33.8 87.0 26.5 57.2 42.1 Pr 939.8 82.6 9.0 4.4 11.9 3.1 7.4 4.7 Nd 3884.6 323.5 46.3 20.6 54.6 13.3 33.9 20.4 Sm 290.9 55.7 14.5 5.9 12.7 2.0 5.5 2.4 Eu 53.3 15.4 4.0 1.7 3.2 0.6 1.2 0.5 Gd 318.4 89.9 23.6 9.5 16.9 2.8 5.6 2.6 Tb 40.6 16.2 4.8 1.9 2.5 0.5 0.9 0.5 Dy 242.4 101.2 34.6 12.2 15.1 3.3 6.1 5.1 Ho 47.7 20.0 7.5 2.4 2.8 0.7 1.4 1.3 Er 136.4 51.9 24.0 7.1 8.1 2.2 4.3 5.1 Tm 16.7 5.0 3.0 LO LO 0.4 0.6 0.9 Yb 89.1 19.6 14.1 5.3 3.3 1.2 2.2 5.6 Lu 11.1 2.2 1.7 0.8 0.4 0.2 0.4 0.8 REE Totals 19 051.7 3284.7 508.6 189.8 360.6 110.4 199.9 160.0 Additionally, the results of the daily analytical tests for the washed raffinate are shown in Tables 13A and 13B below. These data indicated some variation in the removal of chloride and sodium ions from the extractant when using water as the washing medium. Furthermore, the washing stage did not reach a steady-state condition until after day 4. Table 13A: Washing Stage of Raffinate, Main Metals. (Site: Royal Scot, units mg / L) Day 1 2 3 4 5 6 7 Al 9.4 1.1 17.2 4.0 29.1 0.8 0.6 Ca 19.2 0.4 43.3 14.0 53.7 5.8 4.6 Co 0.0 0.0 0.1 0.0 0.3 0.0 0.0 Fe 0.6 0.0 0.3 0.1 0.1 0.1 < 0.022 Mg 7.5 0.1 16.0 6.7 37.2 7.5 8.1 Mn 6.3 0.0 13.4 13.7 61.4 7.3 5.5 Na 19.8 0.4 58.9 17.3 137.9 25.7 27.2 Yes 3.0 0.5 3.0 2.3 2.8 2.3 2.3 Total Main Metals 65.9 2.4 152.3 58.0 322.3 49.5 48.3 ζ / αηηη / ζζηζ / Ε / γίΛΐ Table 13B: Refining Washing Stage, REE. (Site: Royal Scot, units mg / L) Day 1 2 3 4 5 6 7 Se < 0.037 < 0.037 < 0.037 < 0.037 < 0.037 < 0.037 < 0.037 Y 344.3 246.2 62.4 92.2 96.5 165.3 9.4 La 776.6 37.7 470.5 19.9 30.6 36.4 21.1 Ce 1098.4 104.1 429.7 47.9 50.9 107.0 62.2 Pr 125.7 17.5 49.1 7.7 7.5 17.9 10.2 Nd 501.5 91.2 203.1 39.0 37.1 91.3 51.9 Sm 42.8 30.3 23.6 13.0 11.4 30.4 15.0 Eu 9.6 8.0 4.7 3.4 3.4 7.9 3.5 Gd 58.0 47.3 24.6 19.7 19.8 44.6 18.2 Tb 10.6 8.4 2.5 3.1 3.5 6.8 1.8 Dy 66.2 50.1 13.0 18.1 21.5 37.3 6.1 Ho 12.5 9.2 2.3 3.3 3.9 6.6 0.7 Er 34.1 23.6 6.2 9.0 9.2 14.6 0.8 Tm 3.8 2.4 0.7 1.1 0.8 1.2 0.0 Yb 19.9 8.3 2.9 5.0 1.8 3.1 0.3 Lu 1.9 0.8 0.2 0.7 0.2 0.4 0.1 Total REE 3105.9 685.0 1295.7 283.1 297.9 570.7 201.3 Precipitation module The precipitation module used to recover the rare earth elements (REEs) from the separated raffinate is shown in Figure 19; this is on a much smaller scale than the rest of the ALSX plant equipment. The precipitation module consists of a suspended mixer used to agitate the separated raffinate as reagents are added to the solution. After precipitation, the separated raffinate is placed in a ten-gallon, conical-bottomed tank, allowing the solids to settle to the bottom overnight. Using the conical-bottomed tank minimized the volume of liquid that needed to be filtered. The final component of the precipitation module (Figure 69) was a small pressure filter that separated the solid and liquid components from the decanted separated raffinate. The drying oven and kiln used to dry and calcine the rare earth oxalates that precipitated from the solution are not shown.This equipment was also used for the acid and water washing procedures described below. Precipitation procedure After all the PLS was processed through the solvent extraction plant, the separated raffinate was collected for processing in the precipitation module. Figure 20 shows the process flow diagram, which resulted in the separation of 62% of a mixed rare earth oxide product. After acquiring a separation head for the separated raffinate, 2.5 g / L of oxalic acid was added to the raffinate, representing approximately 5 times the stoichiometric ratio of oxalic acid to REE. The pH of the separated solution was then raised to 1.5 with 50% NaOH. The pH adjustment was performed in multiple stages, ensuring that the solution temperature did not exceed 80°C. Once the target pH was reached, the solution was allowed to settle overnight until three-quarters of the supernatant remained in the separatory funnel. The remaining quarter was separated using a pressure filter with Whatman Grade 40 ashless filter paper with a nominal particle retention of 8 µm. The precipitate was then dried in a Y amato DX602C oven at 105 °C. A sample of the precipitate was taken and analyzed for REE content, as shown in Table 14. ζ / αηηη / ζζηζ / Ε / γίΛΐ Balance of mass ©1 (1.5S) | 0 0 0 (0.64) | (0.0S) | (0.23) | (¦o'o) 0 r r- —fe 01 1 0 0 0 0 0 0 0 0 (0.01) | 0 0 0 0 0 0 0 0 0 0 0 -S 2 - « TO ^fe TO < o 0 TO ** cu Φ fe 01 ó 0 80 1 —fe ó 80 ó 0 ó Os 0 ó &D 80 <N 01 1 üO O\ ó —η —fe ó co —fe —fe ó ó 80 r-ó e| Ó r*80 Ó de Precipitación 5 S © O £ 0 TO K ·— fe r- 0 O\ ——( 01 Oí a 0 q ri rj । < ‘O q rj O q co rC —fe 1 0 q G¿ co re i1 H —fe ^“fe r| ch 0 0 co so 0 rj —fe —fe 01 ¿í 61 a 1 —fe oó 80 O O ri —fe ri —fe 08 q 80 co 80 08 08 re ó ri 80 । < re -f co ri co 00 q 06 Ά 80 ri 00 ^“fe r- O q 80 08 q re re >e lance de Masa de las Etapas Iniciales o Ό Ό K í* Λ 5 a r. fe Q Ί5 TO K aí £ -ίο o 80 -íΙ- Ο 0 ó ri q ri r^ Ó zf H ó ·η 0 ó 'Λ \¿ 01 o ó O ó 0 0 ó 0 ó O Ó 0 0 Ó OOO 0 ó 0 0 ó OO Ó 0 0 ó 0« Ό OO « TO £ « O Φ * « 0 TO £ oo H Γγ d Oí a T 80 —fe •t —fe q 0 cc q co <o q 80 r- 08 CO ó u 0 0 —fe co -fe 1-1 Έι g.ó q 80 80 Γ-q 00 08 80 q —fe r' co 08 ó —fe 80 (-· q od —fe 00 re Ensavo v Bal to £ to to A £ c TO *** 0? << Pí O Ό TO TO & Φ (Λ Γ' |ύ -T <Ί 0 0 0 co r! e¡ Ό Ó 1- -T 0 Ó 80 -fe •r, O —fe 0 0 Ó OO CO S 0 O 08 —fe re ó 1- ——< ó ó co ó ó ó 01 01 Tabla <b * 73 a a © © — © a a TO — TO F n a s TO W Φ ÍJ CuM (Λ ( / ) co —fe d 01 a o 80 <5 1^-’ O 00 -r 0 0 ~T Ó CO q 100 Γ l- O cc •r, q re —fe re X 0 0 O CO C / 0 80 re —fe 0 08 ri ri q r) —fe 80 re ri —fe —fe q ue £ 0 ^r, úe 80 CO —fe ——i Os q re 00 co ΓΙ 08 -T 00 80 ri 08 O 80 ΓΊ & ΙΛ 0 TO a ¿ fi a? 3 g q 'ω TO TO (Λ Φ S © IZ to TO φΟ fi Ξ « u 0 U Φ 01 β c« 0 (Λ í H 0 a φ 3 w TO (Z TO M (Λ « 0 / U £ z a (Λ s w Ό 0 Λ H >. g / ann / zz / E / yLi ​,___ o ο o o o o o o o o o o o o o o 0® o o o o Vi Vi r <j o r| -r ψ V1 Oí Vi o Vi Vi ν< —H ^1* Oí Vi r-Η τ—1 o 1 < -r -H -H 0X1 2. O o O O o O O -r o o ο Ó Ó o o —H ó ó —< 0® Οί o O co GO O o vo o Vi ο w-f t-' o 1' Oí ó O r- r- o r- CO o 1— -τ r i Oí -t ó Ί\ Oí % o Ό w Γ i Ί S ο a x> s Λ κ w HHH nJ ζ / αηηη / ζζηζ / Ε / γίΛΐ The precipitation process with oxalic acid resulted in 190 g of precipitate that contained 11.1 g of REE. This represents a recovery of TREE of 97%. Most of the main analytes were removed from the solution during precipitation with the exception of Ca, which coprecipitated completely with the REEs. The REE oxalate precipitate was then calcined in a Lindberg muffle furnace at 750°C for four hours. A sample of this material indicated that the calcination procedure resulted in nearly doubling the concentration of the REO product from 5.8% to 11%, as shown in Table 15. Additionally, 22% of the dry product consisted of Ca. To further concentrate the REO product, a series of washing steps with water and acid were implemented. ζ / αηηη / ζζηζ / Ε / γίΛΐ | Table 15: Analysis of Cleaning Process by Precipitation. Base of Lavado Acid mg / kg 19 456 | 91 848 | 961 | 1 ni 15 975| 1 ï 98 1S3 | 20 | mg / kg 1 | ?OS 861 | f ¨0 67 117 494| 17 646 | 1 6¨ ¨8 29 607 | 1- SO r- r| r| O το Γ- I 38 104 I | 9869 | 99¨ 81 Masa del Producto de Lavado Acido bl Ι- Ο SO O 00Ό O ó 00'0 6ΙΌ O ó 0.00 00Ό 01 1 o -t O ^1 ó O 0.35 0.09 O 0.08 | 80'0 0 Ensayo de Producto Acido cc mg / kg 1- 13 947 p SO C / 0 v 4 O mg / kg 606 74 811 25 532 6595 36 883 6019 I 33 201 I 6609 16 236 Masa del Producto Lavado bl O ó 18.98 00'0 o ó 0.01 049 ”0 0 00Ό 00Ό 01 1 00 9f0 OS Ó O ó Ó r | SO Ó O ó 1 ¿¿Ό I Ó 8Γ0 Ensayo de Producto Lavado 68.5 mg / kg ίο; r1 0.02 το 01 1 3.50 0.54 sq «——< oo r| O 0.48 THE r- you | -9 0 | TH OO Calcined Product Assay 94.36 | mg / kg gold | 1^1,222,201 | so ·—— ^1 | ffK p 0Ό OO r| r— mg / kg 1 37 128 | 17251 2916 | 15,021 | 5041 | X ^1 SO I-- 1149 | I 6546 I 1 sin 1 Analyte 1 Mass (g) | Main Ions u © u & 01 a (Λ Ó (Λ | TMM | Rare Earth Elements (Λ & u £ a (Λ sw Ό 0 .a >o O M). ζ / αηηη / ζζηζ / Ε / γίΛΐ 58 r| O\ r- oo o yr • / Ί QO 'Λ oo Ό Ό o O\ r- oo mr - r | is. ow 50 this µί O r<. Ό or| O Ί Ó o 03 Oí oo 'Aj 05 Tj Ά CO r 1 -T cC —< ^1 <7\ OOO ooo Ó —H r 1 r- o -rr | O Ό O —H or -□ 3 £ > |%c9 011 *011 s 1 1«- oooo ó ó 011 Φ rr·, oo 'Λ > T >rí 01 011 a O oo ó ó 011 o co oo ri -H oii oil a O o O o O ó DX O co 50 β 0 - O ea ζ / αηηη / ζζηζ / Ε / γίΛΐ The washing procedure consisted of multiple washing cycles. After decanting and filtering, the REO product was stirred in 1 L of deionized water for thirty minutes. This procedure was repeated until the conductivity of the supernatant was below 50 pS / cm. In total, ten washing cycles were completed. After washing, analysis of a sample of the REO product indicated that only small portions of the gangue material, Ca (2 g) and Cl (0.7 g), were removed. As a result, a more intensive washing procedure was implemented, where the pH of the wash water was reduced to 3.5 to remove the remaining Ca. The REO product was then subjected to acid washing. This was carried out by placing the REO product in 1 L of deionized water and lowering the pH using 3M nitric acid until a pH value of 3.5 was obtained. During this procedure, noticeable effervescence occurred as the pH decreased. After washing and drying the residual solid material, a significant mass loss was observed as the sample decreased from 68 g to 13.8 g. ICP-MS analysis confirmed that most of the calcium was removed. Figure 21 shows the resulting rare earth oxide product produced at the ALSX plant. The material consisted of a fine, slightly gray powder. Example 5: Economic Analysis The nominal DAM feed rate of the described plant is 500 gpm with a maximum capacity of 1000 gpm. The ideal REE production is projected to be 1000 kg MREO / year or 110 g MREO / h. The plant treats all approximately 456 tons of acid load in the DAM stream per year with an estimated lime consumption cost of $65,000 / year. With a contained value of $237 / kg MREO, the annual throughput can generate annual revenue of approximately $237,000, which is more than sufficient to cover the cost of DAM treatment. The plant is configured so that its DAM treatment train can operate independently and without performance degradation, regardless of whether the REE recovery process is operating on a given day. In one respect, the described processes allow the plant operator to maintain its Clean Water Act compliance obligations regardless of REE recovery. In addition to treating DAM and generating a pre-concentrate, the described plant includes a continuous solvent extraction / acid leaching train at its downstream end that can produce MREO with a grade greater than 90%. The production capacity is estimated to be 15.5 g MREO / hour (Table 16). Table 16: Estimated MREO Production for the Proposed Facility. ζ / αηηη / ζζηζ / Ε / γίΛΐ Upstream Concentrator Product Grade 1% MREO Recovery 90% Upstream Concentrate 803.6 kg MREO / year 82.6 g MREO / hour ALSX Product Grade 90% MREO Recovery 75% Ideal Yield 61.9 g MREO / hour Availability 25% Estimated Yield 15.5 g MREO / hour ζ / αηηη / ζζηζ / Ε / γίΛΐ In some cases, the REE resource at individual DAM treatment sites and individual DAM sludge ponds can be limited. Results from a regional survey showed that the REE flow from an average DAM emitter is only 400 kg / year, while the average sludge pond contains less than 10,000 kg of REE in total. In some respects, neither of these values ​​is large enough to justify a commercial-scale REE refining and concentration plant at a single DAM treatment site. However, in some cases, a dispersed network of on-site handling operations can be integrated to feed a centralized ALSX system. In a feasibility study, we showed that a 2,100 TPD ALSX facility processing raw DAM sludge has the potential to produce an IIR of 37% and a net present value of $80 million over a 20-year operating period.The total capital cost for this plant is $46 million and the operating cost is $141 / kg. A detailed techno-economic analysis showed that these favorable results are sensitive to the acid consumption of the sludge and the moisture content of the sludge feed. For example, Figure 7A shows the maximum possible acid dosage required to keep the total acid cost below an economic threshold of $100 / kg as a function of the REE feed quality and the leaching recovery. As shown, raw sludge (~0.6% REE, ~75% recovery) can only be processed cost-effectively if the maximum acid dosage is on the order of 100 to 150 kg / t. Figure 7B shows a similar analysis where the maximum transport distance required to keep the total shipping cost below 5% of the raw material content value (CV) has been determined as a function of the feed quality and feed moisture. For raw sludge (0.6% REE, 50-80% humidity), the maximum transport distance is almost negligible: less than 10-15 miles. Traditional compliance-based sludge depletion (SDD) treatment tends to lead to unfavorable levels of both sludge acid consumption and moisture. Many SDD treatment operators tend to overdo the lime addition to avoid non-compliant discharges. This practice leaves large amounts of unreacted lime in the final precipitate, and this base must be completely consumed during the acid leaching stage of the treatment processes at a significant cost to the REE producer. Furthermore, traditional sludge drying cells are inefficient at reducing sludge moisture, and many of the sludge samples evaluated in our previous studies had moisture levels exceeding 80–90%. Both of these issues are problematic for commercialization, as they reduce the number of viable sites for sludge that meets the economic viability thresholds.Sludge samples that do not meet the economic thresholds are considered abandoned resources and are not deemed relevant to a regional production scenario. Taken together, these results indicate that the hypothetical 2,100 tonne-per-day (TPD) ALSX plant described herein may have difficulty identifying a sufficient quantity of raw sludge feedstock that meets these criteria. A reduction in the plant's overall throughput will inevitably lead to a proportional reduction in economic results. However, the upstream concentration process described herein offers a comprehensive solution to these problems. Most significantly, the upstream concentrator will increase the quality of the ALSX feed by removing iron and aluminum during the standard water treatment process. Figures 7A-7B illustrate the dramatic impact that the increased feed quality will have on the maximum acid dosage (>4000 kg / t) and the maximum transport distance (increased to >200 miles). In addition to simply increasing the grade, the upstream concentrator provides improved pH control technology to mitigate the acid consumption problems associated with excessive lime addition; furthermore, the use of GEOTUBE® will help reduce product moisture.All of these factors substantially reduce ALSX's processing costs while simultaneously increasing the amount of raw material reaching economic thresholds. If widely implemented in the Appalachian region, DAM / REE's pre-concentration plants will ensure a consistent and reliable supply of raw material for ALSX's operations. This technical-economic analysis (TEA) used standard economic guidelines provided by NETL and incorporates the most recent process knowledge regarding the described ALSX process. Since the upstream concentrator can be readily integrated into existing DAM treatment technologies, the capital and operating costs for this process are assumed to be external to the REE producing entity and are not included in the analysis. However, an additional raw material acquisition cost of $50 / t is included to account for any additional reagent additions, capitalization, or handling expenses required to supply the pre-concentrate to the ALSX plant. The results of this analysis are shown in Table 17 for a nominal 175 TPD plant. Table 17: Economic Indicators for the ALSX Trade System. ζ / αηηη / ζζηζ / Ε / γίΛΐ Economic Parameters Value Plant Feed Rate / Grade 175 TPD at 2% REE Product Rate / Grade 2 TPD at 90% MREO Operating Period 20 years; Discount Rate 10% REE Basket Price $147 / kg REE Recovery 59% Plant Capital Expenditures $20 million Plant Operating Expenses $54 / kg Net Present Value $80 million Internal Rate of Return 61% Payback Period 1.5 years of operation The results confirm the economic gains inherent in upstream concentration before ALSX. Compared to the previous scenario, which treated unprocessed sludge, the current model shows that a similar NPV ($80 million) can be achieved with a much smaller overall plant size (175 TPD vs. 2100 TPD). The smaller plant also implies a much lower capital cost and lower operating cost, $20 million and $54 / kg REE, respectively. While both scenarios have been shown to be economically favorable, the pre-concentration route is much more commercially viable due to the lower raw material requirement and lower capital cost. Both of these factors reduce the overall project risk and are therefore more favorable for investment. Furthermore, Figure 8 shows a sensitivity analysis of operating costs with respect to feed quality and plant size.As shown, for most plant sizes, the greatest incremental reduction in operating costs is achieved. Other commercialization-related issues include regulatory and permitting factors, downstream refining capacity, and REE pricing factors. The waste from the 79 processes described can be easily integrated into existing infrastructure without requiring new permits. This outcome is also advantageous for commercialization, as it minimizes the startup time required to initiate new projects. Regarding refining capacity, the United States currently lacks domestic facilities capable of producing refined REE products from mixed REO. However, this document describes the generation of REO concentrates, which can be used in subsequent refining studies.Regarding pricing, all economic results in Table 17 were determined using a 50% price discount relative to the standard oxide prices provided by NETL. These downstream refining charge price discounts also indicate that the process can still be profitable despite price volatility. Example 6: Removal of Ganga Elements The removal of gangue elements from a DAM feedstock during the preparation of the described PLS using the methods described above is further illustrated in Table 18 below. The data contained therein show that in the first stage at pH 712, aluminum and iron are significantly removed, and in the second stage at pH 718, REE and cobalt are removed from the aqueous phase, i.e., effluent 724, and recovered in the REE-enriched preconcentrate. ζ / αηηη / ζζηζ / Ε / γίΛΐ Table 18. ζ / αηηη / ζζηζ / Ε / γίΛΐ Aqueous phases AQ65 Analito Agua sin Procesar pH 4.7 pH 8.5 Al mg / L 25.5 2.3 0.1 5 Fe mg / L 0.701 0.018 0.053 Mn mg / L 11.8 10.6 9.3 Ni mg / L 0.4 0.4 0.3 Si mg / L 9.1 8.1 6.0 Zn mg / L 1.2 1.1 0.0 Ca mg / L 70.2 119.0 133.1 Mg mg / L 38.1 37.0 37.1 10 Na mg / L 1.6 1.6 1.7 SO4 mg / L 494.5 497.9 483.6 Cl mg / L 0.0 0.0 0.4 total mg / L 653.1 678.1 671.7 Sec ug / L 5.6 0.9 0.1 Y ug / L 174.5 157.0 0.3 15 La ug / L 40.0 37.8 0.3 Ce ug / L 89.8 79.8 0.1 Pr ug / L 19.0 17.9 0.0 Nd ug / L 98.0 89.0 0.2 Sm ug / L 27.3 24.4 0.0 Eu ug / L 6.9 6.2 0.0 Gd ug / L 41.0 36.3 0.0 20 Tb ug / L 5.9 5.3 0.0 Dy ug / L 31.9 27.9 0.0 Ho ug / L 6.1 5.3 0.0 Er ug / L 16.1 13.7 0.0 Tm ug / L 2.0 1.7 0.0 Yb ug / L 11.1 9.2 0.0 Lu ug / L 1.6 1.3 0.0 TREE ug / L 576.8 513.7 1.1 25 Co mg / L 0.4 0.4 0.2 TREE+Co mg / L 577.3 514.1 1.3 The process described results in the removal of gangue elements in the first stage at pH 712, for example, aluminum, iron and silicon; while concentrating REE and cobalt in the preconcentrate after the second stage at pH 718. It should be noted that the modalities described above are merely possible examples of the implementations presented for a clear understanding of the principles of the description. Many variations and modifications can be made to the modality(ies) described above without substantially departing from the spirit and principles of the description. It is intended that all such modifications and variations be included within the scope of this description and be protected by the following five claims.

Claims

1. A loaded leach solution composition obtained from a feedstock of acid mine discharge material comprising: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium; wherein a total concentration of rare earth elements is a sum of concentrations of each of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, and yttrium; wherein thorium and uranium are present in an aggregate concentration of less than 1 mg / L; and wherein the total concentration of rare earth elements is approximately 5 mg / L to approximately 50 mg / L.

2. The loaded leaching solution composition according to claim 1, wherein scandium is present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L; yttrium is present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; lanthanum is present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; cerium is present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L; praseodymium is present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L; neodymium is present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L; samarium is present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L; europium is present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; Gadolinium is present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; terbium is present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L; dysprosium is present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; holmium is present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; erbium is present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L; thulium is present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L; ytterbium is present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L; and lutetium is present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L.

3. The loaded leaching solution composition according to claim 1, wherein iron is present at a concentration less than or equal to approximately 25 mg / L.

4. The loaded leaching solution composition according to claim 1, wherein cobalt is present in an amount of less than approximately 20 mg / L.

5. The loaded leaching solution composition according to claim 1, wherein the loaded leaching solution has a pH of approximately 2.8 to approximately 3.

0.

6. The loaded leaching solution composition according to claim 1, wherein cobalt is present in an amount of approximately 1 mg / L to approximately 30 mg / L.

7. The loaded leach solution composition according to claim 1, wherein the loaded leach solution comprises approximately 50% by weight to approximately 80% by weight of cobalt.

8. The loaded leaching solution composition according to claim 1, wherein scandium is present at a concentration of approximately 0.05 mg / L to approximately 1 mg / L.

9. The loaded leaching solution composition according to claim 1, wherein yttrium is present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L 10. The loaded leaching solution composition according to claim 1, wherein lanthanum is present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L.

11. The loaded leaching solution composition according to claim 1, wherein cerium is present at a concentration of approximately 0.5 mg / L to approximately 7.5 mg / L.

12. The loaded leaching solution composition according to claim 1, wherein praseodymium is present at a concentration of approximately 0.05 mg / L to approximately 2.5 mg / L 13. The loaded leaching solution composition according to claim 1, wherein neodymium is present at a concentration of approximately 0.5 mg / L to approximately 10 mg / L.

14. The loaded leaching solution composition according to claim 1, wherein samarium is present at a concentration of approximately 0.1 mg / L to approximately 2.5 mg / L.

15. The loaded leaching solution composition according to claim 1, wherein europium is present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L.

16. The loaded leaching solution composition according to claim 1, wherein gadolinium is present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L 17. The loaded leaching solution composition according to claim 1, wherein terbium is present at a concentration of approximately 0.05 mg / L to approximately 1.5 mg / L 18. The loaded leaching solution composition according to claim 1, wherein dysprosium is present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L.

19. The loaded leaching solution composition according to claim 1, wherein holmium is present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L 20. The loaded leaching solution composition according to claim 1, wherein erbium is present at a concentration of approximately 0.1 mg / L to approximately 5 mg / L 21. The loaded leaching solution composition according to claim 1, wherein the tube is present at a concentration of approximately 0.05 mg / L to approximately 2 mg / L 22. The loaded leaching solution composition according to claim 1, wherein ytterbium is present at a concentration of approximately 0.05 mg / L to approximately 5 mg / L 23. The loaded leach solution composition according to claim 1, wherein lutetium is present at a concentration of approximately 0.01 mg / L to approximately 1 mg / L. SUMMARY In one aspect, the description relates to a continuous process for treating acid mine drainage while simultaneously recovering a high-quality rare earth pre-concentrate suitable for the extraction of commercially valuable rare earth oxides. In a further aspect, the pre-concentrate contains approximately 0.1% to 5% rare earth elements on a dry weight basis. In another aspect, the description relates to a method for processing the pre-concentrate to generate a loaded leach solution that does not form gels or emulsions and is suitable for processing by solvent extraction. In another aspect, the description refers to a system and a plant to carry out the described process.In yet another aspect, description 10 refers to a composition containing rare earth elements produced by the process described herein. This summary is intended as an exploratory tool for research purposes in the particular art and is not intended to be limiting to the present description.