Collector compositions and processes of using the same

Abstract

The present invention relates to a collector composition comprising at least one compound of formula (I), a process for separating value minerals from ores, comprising adding said collector composition comprising at least one compound of formula (I) and the use of said collector composition for recovering value minerals from ores by flotation.

Description

COLLECTOR COMPOSITIONS ANDPROCESSES OF USING THE SAMEField of the Invention

[0001] The technological concept disclosed herein generally relates to formulations of collector compositions for the recovery of value minerals from mineral ore bodies. More particularly, the disclosed subject matter relates to dithiophosphonate-based collector compositions and methods for using the same.Background

[0002] Froth flotation is a process for beneficiating ores containing valuable minerals generally named as “value minerals”, in particular, for the beneficiation of metallic sulfide mineral values from sulfide ores. Value minerals refer to the metal or metals, mineral or minerals that are the primary object of the flotation process, i.e., the metals.

[0003] Prior to the froth flotation step, the ore is crushed and finely ground to reduce the ore particle size and liberate the value minerals from the associated gangue. The obtained ore slurry is then transferred to flotation cells, and the target minerals are subsequently collected with the use of chemical reagents, such as frothers, collectors, modifiers, and depressants.

[0004] Chemical reagents, referred to as “collectors,” are commonly added to the froth flotation process to facilitate the separation. Certain theories and practices indicate that the success of a flotation process for base metal sulfide and precious metal ores depends on the collectors, which impart selective hydrophobicity to the value mineral(s) which allows them to be separated from other minerals.

[0005] Other reagents, such as “frothers”, may be added to the process to provide a suitable froth phase that helps capture hydrophobic value minerals and facilitate separation and recovery thereof. Certain other reagents, referred to as “modifiers”, may be used to enhance the separation and recovery of the desired minerals and / or metals. Modifiers, which can include pH regulators, may be used to modify and control the pH of the ore pulp in order to enhance the separation and recovery of the desired minerals and / or metals. In some instances, compounds referred to as “activators”, such as copper sulfate, may be usedto activate a certain value sulfide mineral in order to enhance collector adsorption on this sulfide mineral.

[0006] Froth flotation is especially useful for separating finely ground value minerals from the associate gangue or for separating value minerals from one another. Because of the large scale on which mining operations are typically conducted, and the large difference in value between the desired minerals and the associated gangue, even relatively small increases in separation efficiency provide substantial gains in productivity.

[0007] Currently, a large variety of collectors such as xanthates, dithiophosphates, thionocarbamates, dithiocarbamates, monothiophosphates, dithiophosphinates, etc, are utilized as collectors in the flotation recovery of value minerals from sulfide and precious metal ores.

[0008] Among them, one of the most commonly used and best-performing collectors for polymetallic and copper-gold ores is Aerophine® 3418 A, a dithiophosphinate based collector (US 3,355,017; CA 762988). Aerophine® 3418A exhibits a strong and selective affinity towards value sulfide minerals that include copper and lead sulfides as well as precious metals. Advantages in the use of Aerophine® 3418A include highly stable flotation circuit operation, improved selectivity against iron sulfide gangue, increased precious metal recoveries, reduced total collector consumption for Cu and / or Pb flotation, low environmental toxicity, and increased flotation kinetics leading to higher recoveries of these values.

[0009] As selectivity and recovery are key performance indicators that describe the efficiency for a froth flotation process, it is a great challenge to succeed in optimizing both parameters to achieve the best economic yield while maintaining the quality of the final product.

[0010] Thus, while the various collectors and collector formulations have some merits and applicability in froth flotation processes, new collector compositions and improved froth flotation processes are still needed in industry. The need is heightened by the declining ore grades and poor quality ores being processed.

[0011] Moreover, such collector compositions that also demonstrate improved flotation recovery, improved concentrate grade, and desired lower mass recovery would represent a valuable advancement in the art and could gain rapid acceptance in the industry.Summary

[0012] The foregoing and additional objects are attained in accordance with the principles of the invention, wherein the inventors detail the surprising discovery that a dithiophosphonate-based collector, when used in a froth flotation process, makes it possible to improve recovery and selectivity.

[0013] Specific functional groups targeting both recovery and selectivity lead to superior performance of the collector compositions described herein, compared to collectors of the prior art in mineral flotation processes.

[0014] Accordingly, in one aspect, the present invention provides collector compositions comprising at least one compound of formula (I):wherein X represents H, NH4, a substituted ammonium, an alkali metal, or an alkaline earth metal;Ri and R2 are each independently an alkyl group having from 1 to 12 carbon atoms that may be linear, cyclic or branched, an alicyclic radical, an aralkyl radical, an aryl radical, and an alkaryl radical.

[0015] In another aspect, the invention relates to processes for separating value minerals from ores, comprising adding a collector composition comprising at least one compound of formula (I) as defined previously.

[0016] In another aspect, the invention relates to the use of a collector composition comprising at least one compound of formula (I) for recovering value minerals from ores by flotation.

[0017] In another aspect, the invention provides a compound of formula (I):wherein X is H, NH4, a substituted ammonium, an alkali metal, such as lithium, potassium, sodium, or an alkaline earth metal, such as calcium and magnesium;Ri is an isobutyl group and R2 is alkyl group selected from the list consisting of, isopropyl, butyl, pentyl and 4-methyl-2- pentyl.

[0018] This summary of the invention does not list all necessary characteristics and, therefore, subcombinations of these characteristics or elements may also constitute an invention. Accordingly, these and other objects, features, and advantages of this invention will become apparent from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying Examples.Detailed Description

[0019] The present disclosure generally relates to collector compositions used in the recovery of value minerals from an ore, and froth flotation processes employing those compositions.

[0020] As summarized above, the present invention is based at least in part on the discovery that dithiophosphonate-based collector compositions according to the invention provide improved performance as collector compositions for the beneficiation of ores containing sulfide and / or oxide minerals and / or metals via mineral flotation processes. As those skilled in the art will appreciate, ores contain, inter alia, both “value” and “nonvalue” minerals. In this context, “value” mineral(s) refer to the metal(s) or mineral(s) that are the primary object of the flotation process, i.e., the metals and / or minerals from which it is desirable to remove impurities. Examples of metals of interest include, but are not limited to, gold, silver, platinum, palladium and other platinum group metals, copper, nickel, molybdenum, cobalt, lead, and zinc, as well as combinations thereof. The term “non-value” mineral refers to the metal(s) or mineral(s) for which removal from the valuemineral is desired, i.e., impurities in the value mineral. A non-value mineral is not necessarily discarded, and may be considered a value mineral in a subsequent process.

[0021] While any ore may be subjected to the processes and the collector compositions described herein, the disclosed subject matter typically pertains to base metal ores and precious metal ores. Examples of such ores include, but are not limited to, Cu-Mo ores, Cu-Mo-Au ores, Cu-Au ores, primary Au ores, platinum group metal (PGM) ores, Cu ores, Ni ores, Cu-Ni-PGM-Ag ores, and complex polymetallic ores containing Pb, Zn, Cu, Au and Ag.

[0022] The collector compositions and processes described herein provide improvement and / or an unexpected advantage when compared to collector compositions and processes of the prior art.

[0023] Various terms have been defined throughout the disclosure to assist the reader. Unless otherwise defined, all terms of art, notations and other scientific or industrial terms or terminology used herein are intended to have the meanings commonly understood by those of skill in the chemical, flotation, and / or mining arts. In some cases, terms with commonly understood meanings are defined herein for clarity and / or for ready reference, and the inclusion of such definitions herein should not necessarily be construed to represent a substantial difference over the definition of the term as generally understood in the art unless otherwise indicated. As used herein and in the appended claims, the singular forms include plural referents unless the context clearly dictates otherwise. Throughout this specification, the terms retain their definitions.

[0024] As used herein, the term “alkyl” is intended to include linear, branched, or cyclic hydrocarbon structures and combinations thereof. Preferred alkyl groups are those with 12 carbons or below. Lower alkyl refers to alkyl groups from 1 to 6 carbon atoms. Examples of lower alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, s-and t-butyl, pentyl and the like. Cycloalkyl is a subset of alkyl and includes cyclic hydrocarbon groups having from 3 to 8 carbon atoms. Aralkyl is derived from an alkyl radical and refers to a chemical structure consisting of an aromatic ring (aryl group) directly bonded to an alkyl chain.

[0025] The term "alicyclic" as used herein refers to cyclic and aliphatic organic hydrocarbons that do not contain heteroatoms in the ring which can be saturated or unsaturated but do not have aromatic character and may have one or more aliphatic side chains attached. For example, alicyclic groups contain about 3 to about 12 carbons in thering portions of the groups. Thus, alicyclic groups include, but are not limited to cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane.

[0026] The term “aryl” as used herein is a broad term and is used in its ordinary sense, including, without limitation, to refer to a functional group derived from an aromatic hydrocarbon. It usually includes a phenyl group or other aromatic rings like naphthyl, where one hydrogen atom is removed, allowing it to attach to another atom or group. The term “alkaryl” as used herein is a broad term and is used in its ordinary sense, including, without limitation, to refer to an aryl having at least one aryl hydrogen atom replaced with an alkyl moiety. The term “aralkyl” as used herein is a broad term and is used in its ordinary sense, including, without limitation, to refer to an alkyl having at least one alkyl hydrogen atom replaced with an aryl moiety, such as benzyl, phenylethyl, and the like.

[0027] The terms “comprised of’, “comprising” or “comprises” as used herein include embodiments “consisting essentially of’ or “consisting of’ the listed elements, and the terms “including” or “having” in context of describing the invention should be equated with “comprising”.

[0028] Those skilled in the art will appreciate that while preferred embodiments are discussed in more detail below, multiple embodiments of collector compositions and processes described herein are contemplated as being within the scope of the present invention. Thus, it should be noted that any feature described with respect to one aspect or one embodiment of the invention is interchangeable and / or combinable with another aspect or embodiment of the invention unless otherwise stated. It will also be understood by those skilled in the art that any description of the invention, even though described in relation to a specific embodiment or drawing, is applicable to and interchangeable with other embodiments of the invention.

[0029] Furthermore, for purposes of describing the present invention, where an element, component, or feature is said to be included in and / or selected from a list of recited elements, components, or features, those skilled in the art will appreciate that in the related embodiments of the invention described herein, the element, component, or feature can also be any one of the individual recited elements, components, or features, or can also be selected from a group consisting of any two or more of the explicitly listed elements, components, or features. Additionally, any element, component, or feature recited in such a list may also be omitted from such a list.

[0030] Those skilled in the art will further understand that any recitation herein of a numerical range by endpoints includes all numbers subsumed within the recited range (including fractions), whether explicitly recited or not, as well as the endpoints of the range and equivalents. Disclosure of a narrower range or more specific group in addition to a broader range or larger group is not a disclaimer of the broader range or larger group.

[0031] Accordingly, in one aspect, the invention embodies a collector composition comprising at least one compound of formula (I):wherein X represents H, NH4, a substituted ammonium, an alkali metal, or an alkaline earth metal;Ri and R2 are each independently an alkyl group having from 1 to 12 carbon atoms that may be linear, cyclic or branched, an alicyclic radical, an aralkyl radical, an aryl radical and an alkaryl radical.

[0032] In some embodiments, X may be an alkali metal, or an alkaline earth metal.

[0033] In any or all embodiments, the alkali metal may be lithium, potassium, sodium and the alkaline earth metal may be calcium and magnesium.

[0034] In some embodiments, Ri may be an alkyl group having from 1 to 6 carbon atoms, preferably from 2 to 4 carbon atoms. In a preferred embodiment, Ri is an alkyl group having 4 carbon atoms. Preferably, Ri is isobutyl.

[0035] In some preferred embodiments, R2 may be an alkyl group having from 1 to 6 carbon atoms. Preferably, R2 is selected among methyl, ethyl, propyl, isopropyl, butyl, pentyl, 4-methyl-2-pentyl group.

[0036] In some preferred embodiments, the compounds of formula (I) include methoxy isobutyl dithiophosphonate alkali metal salt, ethoxy isobutyl dithiophosphonate alkali metal salt, propoxy isobutyl dithiophosphonate alkali metal salt, isopropoxy isobutyl dithiophosphonate alkali metal salt, butoxy isobutyl dithiophosphonate alkali metal salt, pentoxy isobutyl dithiophosphonate alkali metal salt, 4-methyl-2-pentanoxy isobutyl dithiophosphonate alkali metal salt.

[0037] Examples of specific compounds of formula (I) include methoxy isobutyl dithiophosphonate sodium salt, ethoxy isobutyl dithiophosphonate sodium salt, propoxy isobutyl dithiophosphonate sodium salt, isopropoxy isobutyl dithiophosphonate sodium salt, butoxy isobutyl dithiophosphonate sodium salt, pentoxy isobutyl dithiophosphonate sodium salt, 4-methyl-2-pentanoxy isobutyl dithiophosphonate sodium salt.

[0038] Other examples of specific compounds of formula (I) include methoxy isobutyl dithiophosphonate lithium salt, methoxy isobutyl dithiophosphonate potassium salt, ethoxy isobutyl dithiophosphonate lithium salt, ethoxy isobutyl dithiophosphonate potassium salt, propoxy isobutyl dithiophosphonate lithium salt, propoxy isobutyl dithiophosphonate potassium salt, isopropoxy isobutyl dithiophosphonate lithium salt, isopropoxy isobutyl dithiophosphonate potassium salt, butoxy isobutyl dithiophosphonate lithium salt, butoxy isobutyl dithiophosphonate potassium salt, pentoxy isobutyl dithiophosphonate lithium salt, pentoxy isobutyl dithiophosphonate potassium salt, 4-methyl-2-pentanoxy isobutyl dithiophosphonate lithium salt, 4-methyl-2-pentanoxy isobutyl dithiophosphonate potassium salt.

[0039] The process for preparing the compound of formula (I) according to the invention generally involves methods known to those skilled in the art such as reacting a monoalkylphosphine with sulfur and an alcohol at a temperature between 50-150 °C. A base is then added, whereby there is a neutralization reaction, which makes it possible to generate the dithiophosphonate collector compounds. Suitable bases for salt formation are potassium hydroxide, sodium hydroxide, ammonia, divalent metal bases such as calcium hydroxide, organic bases such as pyridine, other amine bases such as triethyl or trimethyl amine, and other neutralization agents. Depending on the appearance of the product further dilution with water can deliver a liquid formulation.

[0040] In general, the compound of formula (I) is present in the collector compositions in amounts and ratios that are economically feasible as well as effective to the recovery of the value minerals.

[0041] Accordingly, the amount of the compound of formula (I) present in the collector composition can vary between about 1 wt.% and about 99 wt.% based on the total weight of the collector composition. A particular embodiment of the collector composition includes from about 30 wt.% to about 70 wt.% of the compound of formula (I), based on the total weight of the collector composition.

[0042] In some embodiments, the collector compositions may optionally include one or more additives. Many such additives are known to those of skill in the froth flotation art and need not be further described in detail herein. Certain additives may include, for example, one or more of hydrocarbon oils, surfactants, aliphatic alcohols, glycols, glycol ethers, esters, and non-aqueous solvents.

[0043] The amount and type of additives present in the collector composition may vary depending on one or more of the following variables: the type of the compound of formula (I), the amount of the compound of formula (I), the type of ore, the value mineral, and the like. The person of ordinary skill in the art will be able to determine such values based on no more than routine experimentation. In one embodiment, the total amount of additives present in the collector composition is between about 1 wt.% and about 95 wt.% based on the total weight of the collector composition. In another embodiment, the total amount of additives present in the collector composition is between about 1 wt.% and about 50 wt.% based on the total weight of the collector composition.

[0044] The compound of formula (I) as described herein proves useful as value mineral collectors and may be used in methods for recovering at least one value mineral and / or metal from an ore. Flotation methods are well established and are known to those of ordinary skill in the art.

[0045] Thus, the invention also relates to a process for separating value minerals from ores, comprising adding a collector composition comprising at least one compound of formula (I) as defined previously. In general, the compound of formula (I) is utilized as collectors in froth flotation processes by adding an effective amount of collector sufficient to effectively separate the value minerals from the non-value minerals to one or more stages of the froth flotation process. One example of a froth flotation process includes crushing an ore to form crushed ore (referred to herein as the “pre-grinding” or the “pre-grind” stage), mixing the crushed ore with water, and then grinding the particles in a grinding mill to form ground ore. The steps of grinding the ore and forming the slurry may be collectively referred to as the “grinding stage”. After grinding, there is a “classification stage,” where the ground particles are separated based on their size and density using hydrocyclone or simply cyclone. The finer / lighter fraction of the ground ore is sent to the “conditioning stage,” while the coarser / heavier fraction is sent to a separate grinding mill for further grinding. The conditioned ground ore is then subjected to a flotation process by passing airthrough the slurry in floatation cells or a bank of flotation cells to cause flotation of the desired minerals or metals in a froth (referred to as the “flotation stage”). The desired minerals and / or metals, i.e., the value minerals, are collected (“recovered”) from the froth in launders. The addition of the collector compositions may be added to the grinding stage, classification stage (the finer / lighter fraction and / or the coarser / heavier fraction), the conditioning stage, or the flotation stage.

[0046] As one of ordinary skill in the art will appreciate, a froth flotation process may include more than one stage of grinding, classifying, conditioning and flotation. Thus, the flotation concentrate from the first stage (referred to as “roughers” or “rougher-scavengers”) may be ground further, classified, conditioned, and refloated in a circuit referred to as “cleaners” to increase the content or grade of the value minerals or metals. Alternatively, the concentrate from the first stage may be refloated in the cleaners without further grinding. The cleaner circuit may comprise as many stages as are required to attain the specified grade of the value minerals or metals.

[0047] The tails from the cleaners may be refloated in a circuit referred to as “cleanerscavengers”. It is envisioned that the disclosed subject matter encompasses addition of froth phase modifiers, monovalent ion modifier enhancing agents and collector compositions at any stage of the process, i.e., addition of the froth phase modifier (and / or monovalent ion modifier enhancing agent and / or collector) in some instance may be done until the second (or third) grinding stage, conditioning stage, or flotation stage.

[0048] Flotation reagents, which include the collector compositions described herein as well as, for example, frothers, pH regulators, froth phase modifiers, dispersants, depressants, and the like, may be added to the crushed ore, ground ore and / or slurry, during the process at any or all of the stages of the froth flotation process. In certain embodiments, the slurry is preferably conditioned with frothers and modifiers to allow sufficient time for their adsorption on the respective interfaces of the mineral particles and the surrounding water, air, or fluid. Typically, the flotation reagents, such as the collector compositions described herein, are intermixed with at least one of the crushed ore, the ground ore, the slurry, and combinations thereof. The term “intermixed” or any variation thereof, as used herein, means any method that can be used to bring two or more items or compounds together and encompasses adding, mixing, combining, incorporating, blending and the like. Similarly, the term “added” or any variation thereof, as used herein, means any method thatcan be used to bring two or more items or compounds together and encompasses adding, intermixing, mixing, combining, incorporating, blending and the like.

[0049] The collector compositions described herein are added to processes for recovering a value mineral from an ore in an amount that is effective (“effective amount” or “beneficiating amount”) to recover the value mineral and / or affect the desired separation. The effective amount of the collector composition may depend on a variety of factors, including the process used, the ore used, the contents of the collector composition, and the like. The person of ordinary skill in the art will be able to determine such values based on no more than routine experimentation. In one embodiment the effective amount of the collector composition added to the process is from about 0.5 gram per ton (g / t) of ore to about 500 g / t. In another embodiment, the effective amount of the collector composition added to the process is from about 1 g / t to about 300 g / t. In a further embodiment, the effective amount of the collector composition added to the process is from about 2 g / t to about 200 g / t. In yet another embodiment, the effective amount of the collector composition added to the process is from about 5 g / t to about 100 g / t. In still a further embodiment, the effective amount of the collector composition added to the process is from about 5 g / t to about 20 g / t.

[0050] The collector compositions described herein are typically added to processes in a liquid form.

[0051] It is understood to those of ordinary skill in the art that the performance indicators in the flotation process include the recovery or yield of the value mineral and the grade or quality of the final product, as there is typically a tradeoff between these two parameters. Plants generally attempt to maximize the flotation recovery while maintaining acceptable grade or vice versa. A poorer flotation grade for the same recovery thus suggests increased flotation of unwanted gangue minerals, and increased frothing properties in certain processes.

[0052] The modifiers are an important class of compounds which substantially enhance the selectivity of the flotation process by being present in the mixture of ground ore, water and the collector composition . There are multiple classes of modifiers, namely dispersants such as sodium polyacrylate, sodium silicate and sodium polyphosphate. Other compounds disclosed in US 8,720,694 B2 to Nagaraj et. al as “froth phase modifiers” are also useful. These are polymers having functional groups preferably selected from the group consisting of hydroxyl groups, hydroxamic acid or hydroxamate functional groups, silane groups,silanol groups, acid groups and acid anion groups, preferably phosphinate groups, phosphinic acid groups, carboxyl groups, carboxylate groups, carboxyl ester groups, sulfonate groups, sulfonic acid groups, phosphate groups, phosphonate groups, and phosphonic acid groups. These polymers can be accompanied by monovalent ion modifiers which are preferably alkali hydroxides or ammonium and organically substituted ammonium hydroxide. Another class of modifiers that are useful are depressants, including reagents such as sodium cyanide, carb oxy-methyl -cellulose and guar gum. In certain embodiments, modifiers can include any of sodium silicate and meta-silicate, sodium phosphate and polyphosphate, carboxymethyl cellulose, guar gum, starch, tannin, lignin sulfonate, and polymers containing carboxyl, sulfonate, phosphonate and other such groups.

[0053] The frothers provide a stable froth; examples include pine oil, aliphatic alcohols where the aliphatic organic group has from 5 to 8 carbon atoms, polyglycols, and polyglycol ethers, esters. Frothers and modifiers may be added individually or collectively to the collector composition.

[0054] The performance of the collector composition when used in mineral flotation processes can be enhanced by the addition of other flotation additives which are known to those skilled in the art. Accordingly, any such flotation additives can be individually or collectively added to any of the embodiments of the collector composition or mineral flotation processes described herein.

[0055] The collector composition according to the present invention may be applied to the flotation of a variety of sulfide and oxide minerals. The collector composition can particularly be used for the flotation of metals or minerals such as chalcopyrite, bornite, chalcocite, covellite, digenite, enargite, villamaninite, geerite, anilite, djurleite, molybdenite, sphalerite, galena, millerite, pentlandite, native copper, native gold, silver, argentite, electrum, tellurides, Au-bearing pyrite, Au-bearing arsenopyrite, stibnite, Au-bearing stibnite, Au-bearing silicates, and for a number of oxide copper minerals such as malachite, azurite, chalcanthite, tenorite, cuprite, pseudomalachite, chrysocolla, and Cu-bearing goethite. In particular, the value minerals are metals selected from gold, silver, platinum, palladium and other platinum group metals, copper, nickel, molybdenum, cobalt, lead, and zinc, and combinations thereof.

[0056] In another aspect, the invention relates to the use of a collector composition comprising at least one compound of formula (I) for recovering value minerals from ores by flotation.

[0057] In another aspect, the invention provides a compound of formula (I):wherein X is H, NH4, a substituted ammonium, an alkali metal, such as lithium, potassium, sodium, or an alkaline earth metal, such as calcium and magnesium;Ri is an isobutyl group and R2 is alkyl group selected from the list consisting of isopropyl, butyl, pentyl and 4-methyl-2-pentyl. Preferably, the compounds are isopropoxy isobutyl dithiophosphonate sodium salt, butoxy isobutyl dithiophosphonate sodium salt, pentoxy isobutyl dithiophosphonate sodium salt and 4-methyl-2-pentanoxy-isobutyl dithiophosphonate sodium salt.

[0058] It has surprisingly been found in the experiments underlying this invention, that the values for the grade and / or recovery of the concentrate obtained by flotation with the collector composition of the invention, as compared to dithiophosphinic-based collector compositions, were increased. According to the usual meaning in mineral processing, recovery for a certain metal is the ratio of the mass of a metal found in the concentrate, divided by the total mass of the same metal in the ore feed, i. e., before the processing, and the grade G is the ratio of the mass m(VM) of the value metal in an ore or beneficiated ore, and the mass m(Ore) of the ore or beneficiated ore, usually expressed in the unit "%" or in g / t in the case of gold, silver or platinum group metal (PGM) : G = m(VM) / m(Ore) * 100 %.

[0059] While various embodiments may have been described herein in singular fashion, those skilled in the art will recognize that any of the embodiments described herein can be combined in the collective. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.Examples

[0060] The following examples are provided to assist one skilled in the art to further understand certain embodiments of the present invention. These examples are intended for illustration purposes and are not to be construed as limiting the scope of the various embodiments of the present invention, as defined by the claims.

[0061] Unless otherwise specifically noted, the following notations are used in the Examples below: “percent,” “%”, “weight%” and “wt.%” denotes weight percent, “g” denotes gram, “g / f ’ denotes gram per ton of ore, “min” denotes “minutes”, “rec” and “Rec” denote recovery of value mineral or metal in the concentrate, “rpm” stands for revolutions per minute, “kg” is kilogram, “ppm” is parts per million on a mass basis (also equal to g / t), “ml” is milliliter, and “L” is liter.

[0062] A variety of alkoxy dithiophosphonate collector compounds were synthesized following the general preparation procedure.Example 1 - General preparation procedure of the dithiophosphonate collectors

[0063] Sulfur (0.5 g, approximately 16 mmol) and an alcohol (5-10 mL) were introduced into a 25 mL three-neck flask equipped with a magnetic stir bar. The flask was securely clamped and connected to a reflux condenser, which was attached to a water source for cooling. A nitrogen inlet was connected to one neck of the flask, while the third neck was used for reagent addition, sealed with a septum. The flask was placed in an oil bath for controlled heating. After purging the system with nitrogen for several minutes to eliminate any residual air, the mixture was stirred and gradually heated to the desired temperature to initiate reflux. Under nitrogen protection, a primary alkyl phosphine (approximately 5 mmol) was slowly added to the flask using a syringe. Following the addition, the mixture was maintained at 80°C for about 60 minutes, resulting in a colorless or pale-yellow solution. After the reaction, excess alcohol was removed via vacuum stripping. The resulting reaction mixture was treated with a base solution at room temperature and filtered through a 0.22 pm syringe filter to yield a solution of the respective dithiophosphonate collectors. The obtained product solution was then analyzed using quantitative NMR (Nuclear magnetic resonance) to determine its purity and concentration.P NMR Characterization of Collector Examples:Collectors Structure31P chemical shift (ppm)Na 122.4 Methoxy isobutyl dithiophosphonate1 s2sodium saltX vEthoxy isobutyl dithiophosponate Na 119.61 ssodium sa2lt / kzPvsNa 118.7 Propoxy isobutyl dithiophosponate 1 s2sodium saltNa 118.4 Isopropoxy isobutyl dithiophosphonate 1S2sodium saltNa 118.0 Butoxy isobutyl dithiophosphonate 1 s2monosodium saltNa 118.6 Pentoxy isobutyl dithiophosphonate 1S2sodium saltNa 4-Methyl-2-pentanoxy isobutyl 122.41S2 1 1dithiophosponate sodium salt 1 p^ JI JINa 115.8 Benzoxy isobutyldithiophosponate 1 s2sodium saltX)Na Methoxy cyclohexyl dithiophosponate 129.7 S2sodium salt _1 1 ^ °Na Ethoxy cyclohexyl dithiophosponate 126.6 S2sodium saltNa Isopropoxy cyclohexyl 124.5 S21dithiophosponate sodium salt _ P^ ±Na 135.0 Methoxy tert-butyl dithiophosponateS2sodium saltXTNa 131.4 Ethoxy tert-butyl dithiophosponateS2sodium salt \^PSo / \Na 129.0 Isopropoxy tert-butyl dithiophosponateS21 sodium saltX P^ XNa 122.7 Methoxy 2,4,4-trimethylpentyl\ / 1 dithiophosponate sodium saltEthoxy 2,4,4-trimethylpentyl Na 119.2 dithiophosponate sodium salt \ / 1Isopropoxy 2,4,4-trimethylpentyl Na 116.8 dithiophosponate sodium salt \ / 1S2- V JL I- - JLFlotation tests:

[0064] The alkoxy dithiophosphonate sodium salts collector compounds prepared in Example 1 were tested in laboratory Denver flotation cells against Aerophine® 3418A on copper-gold and polymetallic ores.Example 2 - Recovery of Pb and Ag values from a lead-zinc-silver sulfide ore using 4-methyl-2-pentanoxy -isobutyl dithiophosphonate

[0065] A lead-zinc-silver sulfide ore was ground in a rod mill resulting in a slurry with particle size distribution of 80% passing 100 mesh particle size. The plant follows a sequential flotation process where the Pb and Ag minerals are floated first in the Pb circuit followed by activation and flotation of Zn sulfide in the Zn circuit. The Zn and Fe sulfides are purposely depressed in the Pb circuit in order to minimize the recovery of Zn so that more Zn can correctly report to the Zn concentrate. The Ag recovery into the Pb concentrate is preferred due to high payments relative to its recovery into the Zn concentrate. In this example, only the Pb flotation tests were conducted in order to maximize the recovery of Pb and Ag. Approximately 40 g / ton of Zn(CN)2 and 0.28 g / ton of lime were added to the grinding stage and used as Zn and Fe depressants. The ore was floated with 10 g / ton of collector, 15 g / ton of methyl isobutyl carbinol (MIBC) frother and additional 5 g / ton of pine oil frothers in a Denver flotation machine. Aerophine® 3418A (purchased from Syensqo SA) and 4-Methyl-2-pentanoxy-isobutyl dithiophosphonate sodium salt were used as the respective collector in two separate tests on representative samples on this ground ore. The lead flotation circuit was conducted, and the concentrates were removed over a period of 6 minutes. The concentrates and tailings were then dried, weighted, and assayed for lead, silver, zinc, and iron, which allowed for the calculation of value (lead, zinc, and silver) and gangue mineral recoveries and concentrate grades, as given in Table I below. Note that Zn is undesired in the Pb circuit - Zn is recovered in the subsequent Zn flotation stage.Table I.Aerophine® 3418A 4-Methyl-2-pentanoxy- (comparative) isobutyl dithiophosphonate sodium saltPb Recovery (%) 81.6 86.0Pb Grade (%) 3.1 3.2Ag Recovery (%) 63.3 63.8Ag Grade (g / t) 181.2 192.4Zn Recovery (%) 14.9 12.5Zn Grade (%) 2.6 2.1Fe Recovery (%) 4.8 4.8Fe Grade (%) 4.0 3.9

[0066] The dithiophosphonate collector gave higher lead and silver recoveries than were obtained with the Aerophine® 3418A collector. Typically, the large increase in Pb recovery obtained with the dithiophosphonate collector would result in a much lower Pb grade. In this example, the Pb grade actually increased slightly which is a result of the dithiophosphonate collector selectivity and is exemplified in the desired reduced recovery of Zn in the Pb circuit.Example 3 - Recovery of mineral values from a copper-gold ore using Ethoxy isobutyl dithiophosphonate

[0067] A copper-gold ore was ground in a rod mill at 60% solids in water to achieve a particle size distribution of approximately 80% passing 80 mesh. Lime was added in the grinding mill at 1.2 g / ton resulting in a pulp pH of approximately 10-10.5. The pulp was conditioned with a collector and a frother and floated for 6 minutes. The collector dosage was 20 g / ton, and 18 g / ton Oreprep OTX-140 (purchased from Syensqo SA) was used as frother. Two flotation tests were run, where Aerophine® 3418A and Ethoxy isobutyl dithiophosphonate sodium salt were used as collectors. The recoveries and concentrate grades of copper, gold, and iron are given in the following Table II.Table IIAerophine® 3418A Ethoxy isobutyl (comparative) dithiophosphonate sodium saltCu Recovery (%) 64.9 73.4Cu Grade (%) 7.4 4.0Au Recovery (%) 44.4 62.9Au Grade (g / t) 5.2 3.5Fe Recovery (%) 10.3 26.1Fe Grade (%) 27.6 35.6

[0068] The data above demonstrated that the dithiophosphonate collector recovered more copper than Aerophine® 3418A. The gold in this ore was contained in iron sulfides and the industry need in such ores is a collector that can effectively float the gold containing iron sulfides while also floating the Cu minerals. The dithiophosphonate collector of the present disclosure significantly improves recovery of the gold values that occur with the iron sulfides in this challenging ore. The larger amount of iron sulfides may be rejected in the cleaning stages after regrinding and increasing the pH.Example 4 - Recovery of metal values from a copper-gold ore using 4-methyl-2-pentanoxy-isobutyl dithiophosphonate

[0069] An ore body containing Cu and Au values was beneficiated by flotation. The need in this ore is to float the Cu and Au values while minimizing the flotation of Fe sulfides and problematic non-sulfide gangue minerals. The ore was ground for 8 minutes to minus 80 mesh in particle size and in the presence of 0.8 g / ton lime. The ground ore was floated for 8 minutes with Aerophine® 3418A or 4-methyl-2-pentanoxy-isobutyl dithiophosphonate sodium salt as the collector at 10 g / ton and with 35 g / ton Oreprep OTX-140 frother. The recoveries and grades of copper, gold, and iron are summarized in Table III below. The recovery of acid insolubles, which are minerals that are insoluble in acid digestion and can be used as a proxy for non-sulfide gangue, is also included in Table III.Table IIIAerophine® 3418A 4-Methyl-2-pentanoxy- (comparative) isobutyl dithiophosphonate sodium saltCu Recovery (%) 75.4 74.9Cu Grade (%) 1.8 2.4Au Recovery (%) 73.9 72.3Au Grade (g / t) 1.0 1.1Fe Recovery (%) 17.5 14.2Fe Grade (%) 9.8 10.7Acid Insols Recovery (%) 12.2 8.9Acid Insols Grade (%) 56.1 54.2

[0070] While the dithiophosphonate collector had similar copper and gold recoveries to Aerophine® 3418 A, the data demonstrated that the dithiophosphonate collector selectively rejected iron and acid insoluble gangue minerals better. As a result, the use of dithiophosphonates will give higher concentration grade and maintain the recovery of copper and gold at desired levels.Example 5 - Recovery of Pb and Ag values from a lead-zinc-silver sulfide ore using Pentoxy isobutyl dithiophosphonate

[0071] A lead-zinc-silver sulfide ore containing 0.24% Pb, 1% Zn, and 17 g / ton Ag was floated to recovery Pb and Ag in the Pb flotation stage while minimizing Zn and Fe flotation. The ore was ground at 60% solids in water to a particle size of approximately 80% less than 100 mesh and in the presence of 0.25 g / ton lime to achieve pH of 8, 1.7 g / ton zinc cyanide, and 10 g / ton of collector (Aerophine® 3418A or pentoxy isobutyl dithiophosphonate sodium salt). Before flotation, 15 g / ton of MIBC frother and 5 g / ton of pine oil frother were added and conditioned for 2 minutes. The ore slurry was then floated for 3 minutes, at which point an additional 5 g / ton of collector and 5 g / ton of MIBC frother were added and conditioned for 3 minutes, followed by 3 minutes of flotation. The resulting lead concentrates were assayed and summarized in Table IV below.Table IVAerophine® 3418A Pentoxy isobutyl (comparative) dithiophosphonate sodium salt Pb Recovery (%) 80.8 86.2Pb Grade (%) 2.3 1.9Ag Recovery (%) 74.4 73.3Ag Grade (g / t) 161.6 121.5

[0072] The dithiophosphonate collector of the present disclosure gave significantly better lead recovery than the Aerophine® 3418A collector and provided similar silver recovery, while maintaining acceptable metal grades.Example 6 - Recovery of Cu and Au values from a copper-gold sulfide ore with ethoxy isobutyl dithiophosphonate

[0073] An ore body containing 0.9% Cu and 0.1 g / ton Au was beneficiated by flotation to recover Cu and Au values. In this ore, a significant amount of the Au values were contained in Fe sulfides and the industry need in such ores is to improve both Cu and Au flotation while minimizing excessive Fe recoveries. The ore was ground to minus 100 mesh in particle size and in the presence of 0.38 g / ton of lime to achieve a slurry pH of 10.5. Approximately 14 g / ton of collector (Aerophine® 3418A or ethoxy isobutyl dithiophosphonate) and 22 g / ton of Oreprep OTX-140 frother were used. The ore slurry was floated for 7 minutes. Table V illustrates the recoveries and grades of copper, gold, and iron.Table VAerophine® 3418A Ethoxy isobutyl (comparative) dithiophosphonate sodiumsaltCu Recovery (%) 69.6 84.2Cu Grade (%) 4.3 3.3Au Recovery (%) 47.6 80.3Au Grade (g / t) 0.4 0.3Fe Recovery (%) 54 77.4Fe Grade (%) 26.1 23.6

[0074] The data above demonstrated that the dithiophosphonate collector recovered significantly more copper and gold than Aerophine® 3418 A. Based on the significant improvements obtained with the ethoxy- isobutyl dithiophosphonate_collector, it may be used at lower dosage and still provide benefits in Cu and Au recovery. This would not only provide cost saving per unit metal recovered but also reduce the Fe recovery.Example 7 - Recovery of Cu and Au values from a copper-gold ore using isopropoxy isobutyl dithiophosphonate

[0075] A copper-gold ore containing 0.74% Cu and 0.71 g / ton Au was beneficiated to recover value minerals. The Cu values occurred in both primary and secondary copper sulfide minerals. Additionally, they were partially oxidized which made this ore challenging to process. The ore was ground at 60% solids in water to minus 80 mesh and in the presence of 2.6 g / ton lime, 25 g / ton Oreprep OTX-140 as frother, and 24 g / ton collectors. In this example, a conventional collector, AERO 7249 from Syensqo was used as the primary collector at a dosage of 19.2 g / ton while either Aerophine® 3418A or isopropoxy isobutyl dithiophosphonate was used as the secondary collector at 4.8 g / ton. The ore slurry was floated for 3 minutes, at which point 6 g / ton of additional collector (Aerophine® 3418A or isopropoxy isobutyl dithiophosphonate) was added to the slurry and conditioned for 2 minutes, followed by 3 more minutes of flotation. The concentrate andtail samples were then dried, weighted, and assayed for copper, gold, and iron, as given in Table VI below.Table VIAerophine® 3418A Isopropoxy isobutyl (comparative) dithiophosphonateCu Recovery (%) 55.6 64.7Cu Grade (%) 7.0 5.4Au Recovery (%) 41.5 53.4Au Grade (g / t) 5.2 4.4Fe Recovery (%) 10.9 17.6Fe Grade (%) 29.3 31.6

[0076] The dithiophosphonate collector gave higher copper and gold recoveries than those obtained with the Aerophine® 3418A collector. These improvements were obtained without significant increase in Fe recovery which contained some of the Au values.

[0077] Various patent and / or scientific literature references have been referred to throughout this application. The disclosures of these publications in their entireties are hereby incorporated by reference as if written herein. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference. In view of the above description and the examples, one of ordinary skill in the art will be able to practice the disclosure as claimed without undue experimentation.

Claims

Claims1. A collector composition comprising at least one compound of formula (I):MlR1SX+R'2, (I)wherein X is H, NH4, a substituted ammonium, an alkali metal, or an alkaline earth metal,Ri and R2 are each independently an alkyl group having from 1 to 12 carbon atoms that may be linear, cyclic or branched, an alicyclic radical, an aralkyl radical, an aryl radical and an alkaryl radical.

2. The collector composition according to claim 1, wherein X is an alkali metal or an alkaline earth metal.

3. The collector composition according to claim 1 or claim 2, wherein the alkali metal is lithium, potassium, sodium and the alkaline earth metal is calcium and magnesium.

4. The collector composition according to any one of claims 1 to 3, wherein Ri is an alkyl group having from 1 to 6 carbon atoms, preferably from 2 to 4 carbon atoms, more preferably Ri is an alkyl group having 4 carbon atoms.

5. The collector composition according to any one of claims 1 to 4, wherein Ri is isobutyl.

6. The collector composition according to any one of claims 1 to 5, wherein R2 is an alkyl group having from 1 to 6 carbon atoms.

7. The collector composition according to any one of claims 1 to 6, wherein R2 is selected among methyl, ethyl, propyl, isopropyl, butyl, pentyl, 4-methyl-2- pentyl group.

8. The collector composition according to any one of claims 1 to 7, wherein the compounds of formula (I) include methoxy isobutyl dithiophosphonate alkali metal salt, ethoxy isobutyl dithiophosphonate alkali metal salt, propoxy isobutyl dithiophosphonate alkali metal salt, isopropoxy isobutyl dithiophosphonate alkali metal salt, butoxy isobutyl dithiophosphonate alkali metal salt, pentoxy isobutyl dithiophosphonate alkali metal salt, 4-methyl-2-pentanoxy isobutyl dithiophosphonate alkali metal salt.

9. The collector composition according to claim 8, wherein the compound of formula (I) includes methoxy isobutyl dithiophosphonate sodium salt, ethoxy isobutyl dithiophosphonate sodium salt, propoxy isobutyl dithiophosphonate sodium salt, isopropoxy isobutyl dithiophosphonate sodium salt, butoxy isobutyl dithiophosphonate sodium salt, pentoxy isobutyl dithiophosphonate sodium salt, 4-methyl-2-pentanoxy isobutyl dithiophosphonate sodium salt.

10. The collector composition according to any one of claims 1 to 9, wherein the amount of the compound of formula (I) is between about 1 wt.% and about 99 wt.%, preferably from about 30 wt.% to about 70 wt.% based on the total weight of the collector composition.

11. The collector composition according to any one of claims 1 to 10, wherein the collector compositions include one or more additives.

12. The collector composition according to claim 11, wherein the additives are one or more of hydrocarbon oils, surfactants, aliphatic alcohols, glycols, glycol ethers, esters and non-aqueous solvents.

13. The collector composition according to claim 11 or claim 12, wherein the total amount of additives is between about 1 wt.% and about 95 wt.%, preferably between about 1 wt.% and about 50 wt.%, based on the total weight of the collector composition.

14. A process for separating value minerals from ores, comprising adding a collector composition comprising at least one compound of formula (I) as described in claims 1 to 13.

15. The process according to claim 14, which process is a froth flotation process.

16. The process according to claim 14 or claim 15, wherein the effective amount of the collector composition added to the process is from about 0.5 gram per ton of ore to about 500 g / t, preferably from about 1 g / t to about 300 g / t, more preferably from about 2 g / t to about 200 g / t.

17. The process according to any one of claims 14 to 16, wherein frothers and / or modifiers are added individually or collectively to the collector composition.

18. The process according to any one of claims 14 to 17, wherein the value minerals are sulfide and / or oxide minerals.

19. The process according to any one of claims 14 to 17, wherein the value minerals are metals selected from gold, silver, platinum, palladium and other platinum group metals, copper, nickel, molybdenum, cobalt, lead, and zinc, and combinations thereof.

20. Use of a composition as defined in any one of claims 1 to 13 for recovering value minerals from ores by flotation.

21. A compound of formula (I):MlR2 , (I)wherein X is H, NFU, substituted ammonium, alkali metal, such as lithium, potassium, sodium, alkaline earth metal, such as calcium and magnesium, Ri is an isobutyl group and R2 is alkyl group selected from the list consisting of isopropyl, butyl, pentyl and 4-methyl-2-pentyl.

22. The compound according to claim 21, which compound is isopropoxy isobutyl dithiophosphonate sodium salt, butoxy isobutyl di thiophosphonate sodium salt, pentoxy isobutyl dithiophosphonate sodium salt and 4-methyl-2-pentanoxy isobutyl dithiophosphonate sodium salt.

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