Metal extraction from lithium-ion battery materials

Abstract

The present invention relates to a method for extracting metals from black masses of lithium ion batteries, the black masses containing the anode and cathode materials of the battery, the cathode material comprising lithium and nickel, and further to equipment suitable for use in the method.

Description

Technical Field

[0001] The present invention relates to a lithium-ion battery, and more particularly to a method for extracting metals from a black aggregate obtained from the battery materials. Such a black aggregate mainly contains cathode metal and anode material, and this cathode metal usually contains lithium and nickel, and further possible cathode metals in some cases are cobalt, manganese, and aluminum. The present invention also relates to an arrangement suitable for use in this method.

Background Art

[0002] The use of lithium-ion batteries has been steadily growing over the past few years and even decades, and its importance is expected to further increase as the development of new electric vehicles progresses. Lithium-ion batteries contain several transition metals in the cathode that can be useful when recycled within the battery or recovered from these batteries for other purposes. In particular, the lithium in these materials should be recovered and reused.

[0003] The hydrometallurgical separation of metals from lithium-ion batteries proceeds via the recovery of a black aggregate that contains cathode metal and anode material, but other coarse solid battery parts such as wiring and plastic or steel parts have already been removed.

[0004] The next step in metal recovery after the formation of the black aggregate is typically to separate the cathode metal from the other components of the black aggregate using, for example, mechanical, thermal, or chemical pretreatment steps, followed by acid leaching for solubilization of the cathode metal and preparing them for recovery.

[0005] Each stage of the overall hydrometallurgical process poses a risk of metal loss, which should of course be reduced. The inventors have discovered a new method for reducing lithium loss.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.

[0007] According to a first aspect of the present invention, there is provided a method for extracting metals from a black aggregate obtained from a lithium-ion battery material, the black aggregate containing a negative electrode material and a positive electrode material of a battery. In particular, the metals to be extracted include lithium and nickel, and optionally other transition metals such as cobalt, manganese, and aluminum.

[0008] According to a second aspect of the present invention, there is provided a method aimed at increasing the recovery rate of lithium.

[0009] According to a third aspect of the present invention, there is provided a method including one or more steps for recycling a lithium-containing fraction to a leaching step, providing an increased lithium recovery rate.

[0010] According to a further aspect of the present invention, there is provided equipment suitable for use in carrying out the steps of the method of the present invention.

[0011] The method of the present invention comprises the following steps, namely, - one or more leaching steps, and - a metal separation step necessary for recovering a fraction containing desired transition metals, typically at least lithium ions and nickel ions, and - one or more steps for recycling the lithium-containing fraction to the leaching step, and comprises.

[0012] Similarly, the equipment of the present invention - is one or more leaching units from which a leaching solution containing dissolved metal ions is recovered, the leaching unit, - A metal separation unit for recovering a fraction containing at least lithium and nickel ions, said metal separation unit, and, - One or more recycle lines for guiding one or more additional lithium-containing fractions to the leaching unit, Comprising.

[0013] Accordingly, the present invention relates to the recovery of fractions containing small amounts of lithium mixed in the main lithium fraction, thus increasing the yield or recovery rate of lithium products in the metal separation step.

[0014] Thus, the present invention provides several advantages. Naturally, an increase in lithium yield is achieved. On the other hand, the recycling options of the present invention also simplify the requirements for waste treatment by reducing the amount of lithium in the waste liquid. Lithium can cause problems in waste treatment, and the present method can significantly reduce the amount of lithium in the waste liquid.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0016] [Definitions] As used herein, the term "black mass" is intended to represent a mixture of cathode and anode materials obtained after mechanically separating the macro-components of a battery, and the black mass typically also contains organic compounds such as compounds derived from the electrolyte of the battery, depending on the pretreatment method of the black mass.

[0017] "Organic compounds" are intended herein to include molecules in which one or more carbon atoms are covalently bonded to one or more hydrogen, oxygen, or nitrogen atoms. Thus, for example, graphite or other pure carbon allotropes are excluded from this group of compounds. Other compounds that are generally considered to be excluded from this class of compounds, despite meeting the definition, include carbonates and cyanides, and carbon dioxide, if the only carbon in the compound is based on this group.

[0018] The "anode" is typically formed of, for example, graphite or silicon, which are not solubilized in the leaching of the present invention but are present in the black mass prior to leaching.

[0019] "Cathode material" or "cathode metals" similarly include metal ions such as lithium, nickel, cobalt, and manganese (Li, Ni, Co, Mn), typically in the form of their oxides. The content of these metals in the black mass is preferably all within the range of 1 to 35% by weight. Other examples of cathode components that may be present in the black mass but are generally in smaller amounts include generally small amounts of tin, zirconium, zinc, copper, iron, fluoride, phosphorus, aluminum (i.e., Sn, Zr, Zn, Cu, Fe, F, P, and Al), etc.

[0020] The present invention relates to a method for extracting metals from the black mass of lithium-ion battery materials. The method comprises the following steps, namely, (a) One or more pretreatment steps, in which fractions containing non-metallic materials are separated from the black aggregates, and pretreated black aggregates containing the negative and positive electrode materials are recovered and preferably further processed by leaching, said pretreatment steps; (b) One or more leaching steps, carried out on a metal-containing leaching feed formed from the pretreated black aggregates, combined with recycled lithium precipitate, said leaching steps including an acid leaching step carried out in a solution containing sulfuric acid, whereby the metals of the leaching feed are dissolved and a leaching solution containing the dissolved metals is recovered and preferably further processed by separating the metal fraction therefrom, said leaching steps; and (c) A metal separation step in which an initial fraction of the metal material is separated from the leaching solution and a major fraction containing at least nickel and lithium is recovered, whereby the fraction containing lithium is recovered after the nickel fraction has been recovered, the recovery of said lithium fraction comprising the following steps, namely: i) Reacting lithium to lithium carbonate, then ii) Separating the solid from the liquid, - The solid containing lithium is either recovered as such or reacted to form further lithium products, - Reacting the waste liquid with a phosphate reagent to precipitate the remaining lithium in the waste liquid as a lithium phosphate precipitate, and - Recycling at least a part of the obtained lithium precipitate to the acid leaching step, said step of separating the solid from the liquid, said metal separation step; are provided.

[0021] The black aggregate of a lithium-ion battery usually contains both a positive electrode material and a negative electrode material, as well as an electrolyte material containing an organic compound. For the purposes of the present invention, the organic compound is preferably removed from the black aggregate by the above-described pretreatment step. For example, one or more washing steps can be used, preferably implemented by mixing the battery material with water or an organic solvent, most preferably water, whereby materials dissolved or dispersed in the solvent, such as the organic compound, can be separated from the undissolved components of the black aggregate. Alternatively, one or more heating steps, typically implemented as a pyrolysis or evaporation step, can be used to remove the organic compound, and each such heating step is preferably carried out at a temperature of 195 to 470 °C. A further option is to carry out both a washing step and one of the aforementioned heating procedures.

[0022] Thus, the pretreatment step preferably results in a pretreated black aggregate that contains lithium, nickel, and cobalt of the battery positive electrode, and optionally manganese, in oxide form, more preferably containing less than 3% by weight, most preferably less than 1.5% by weight, of the remaining organic compound.

[0023] In a preferred embodiment of the present invention, at least a portion of the lithium that is typically lost in the optional washing step is recovered by the following steps, namely, - reacting the spent washing solution containing the fraction of separated non-metallic material with a phosphate reagent to precipitate the lithium therein as lithium phosphate; and - separating the lithium phosphate precipitate from the remaining washing solution and combining it with the pretreated black aggregate to be conveyed to the next leaching step.

[0024] ​After the pretreatment step, solid-liquid separation is usually carried out, whereby the pretreated black aggregate is conveyed to the next leaching step and can optionally be mixed with added metal-containing solids or slurries, such as lithium phosphate precipitate recycled from either the pretreatment step or the metal recovery step.

[0025] In one embodiment of the present invention, only one leaching step is used, which is the acid leaching step and is carried out in a solution containing sulfuric acid. Usually, acid leaching is thus carried out by dispersing the pretreated black aggregate in a solution containing acid, adding an optional extractant, and preferably then mixing.

[0026] The temperature during the leaching step is preferably adjustable, whereby, most preferably, the temperature is maintained at a high level during acid leaching, for example, a temperature of 50 °C or higher, preferably a temperature of 50 - 95 °C, and more preferably a temperature of 60 - 90 °C. Similarly, the pressure during acid leaching is preferably maintained at atmospheric pressure or a slightly higher pressure of 100 - 200 kPa. Usually, the solubilization of the target transition metal is completed within 2 - 6 hours.

[0027] The addition of sulfuric acid is used somewhat to adjust the pH of the leaching solution. Thus, the pH of the leaching solution is preferably adjusted to a level of 0 - 5, more preferably 1 - 2, using the sulfuric acid before adding an optional extractant selected from hydrogen peroxide, carbohydrates, and sulfur dioxide, which provides more effective dissolution due to its reducing ability.

[0028] After the leaching reaction is completed, that is, after a sufficient time, for example, 2 - 6 hours, has elapsed under the leaching conditions for the pretreated black aggregate, solid-liquid separation is usually carried out to recover the leaching solution containing the cathode metal, whereby it can be conveyed to the next step of the method to recover a separate metal fraction.

[0029] In one embodiment of the present invention, the recovery of the major fraction of the metal material containing at least nickel ions and lithium ions preferably precedes one or more steps for separating the initial fraction of the metal material from the leaching solution. The said initial fraction of the metal material (or “the initial metallic fractions”) usually contains at least one of iron, aluminum, calcium, and fluoride ions, and possibly phosphate, if any. This order of steps has the advantage of obtaining a purified solution for the recovery of the major fraction of the metal material, since the initial fraction contains substances that are considered to belong to the impurities. These substances would also impair the subsequent recovery of the major fraction, or at least reduce the purity or yield, if they remained in the leaching solution.

[0030] Preferably, the step of separating the initial fraction of the metal material from the leaching solution includes the step of separating two or more, preferably three or four, most preferably all of iron ions, aluminum ions, calcium ions, and fluoride ions. Copper is also included in these initial fractions. Optionally, another copper recovery step can be carried out, preferably before the other initial fractions are separated from the solution.

[0031] Typically, the separation of the initial fraction of the metal material includes at least one step carried out as solvent extraction (SX), which is intended to remove the said impurities such as iron and aluminum from the leaching solution, and optionally preceded by solid separation to remove the impurities already in solid form, thus improving the selectivity and performance of the solvent extraction.

[0032] In another alternative, the separation of the initial fraction of the metal material comprises at least one step carried out as a precipitation, for example a hydroxide precipitation aimed at removing impurities such as iron and aluminium from the leaching solution as a solid fraction from the leaching solution. Such hydroxide precipitation has also been shown to be effective for the precipitation of phosphates such as the phosphate of recycled lithium phosphate obtained from the lithium recovery step and optional pretreatment steps.

[0033] In a particularly preferred alternative, the separation of the initial fraction of the metal material includes precipitation, optionally followed by separation of the precipitated impurities and then solvent extraction, both steps being as described above. The advantage of such a two-stage impurity separation is that the content of impurities such as iron and aluminium is further reduced in the thus purified leaching solution. In such a two-stage separation of the initial metal fraction, it is particularly preferred to carry out the precipitation before the solvent extraction, as this facilitates the high selectivity in the solvent extraction.

[0034] When copper is recovered separately, this copper recovery step is preferably carried out before the said initial fraction of the metal material is separated from the leaching solution, because copper can have an adverse effect on the subsequent recovery rate and, more importantly, on the quality of the product.

[0035] Since the acid leaching step is carried out in an acid solution, the first metal separation step is required to withstand acidic conditions. This requirement is met by the separation of the initial metal fraction.

[0036] To perform the separation and recovery of the metal, various reactions and procedures can be utilized, such as additional leaching or washing steps, solvent extraction, precipitation, ion exchange steps, and electrolytic deposition steps. However, for the separation of the initial metal fraction, it is preferable to utilize at least one solvent extraction, because this increases the purity of the remaining solution and facilitates the subsequent recovery of the major fractions, particularly the recovery of cobalt and nickel, thereby enabling the recovery of all the metals in the major fractions in high yield and high purity, typically as battery-grade materials.

[0037] As described above, the recovery of the major fraction of the metal includes at least the steps of recovering nickel ions and lithium ions, and optionally cobalt and manganese, although the order of recovery can vary.

[0038] In particular, the recovery of the major fraction includes the step of recovering at least one, preferably both, of manganese and cobalt in addition to the nickel ions and lithium ions. Usually, all of manganese, cobalt, and nickel are recovered before the lithium.

[0039] Therefore, lithium recovery is preferably carried out after the separation of the initial metal fraction, and more preferably after any of manganese, cobalt, and nickel present in the leach solution has been recovered. Using this preferred order of steps results in a situation where lithium can be recovered from a high-purity lithium-containing solution.

[0040] Lithium is recovered by reacting the lithium to form a carbonate, producing a product fraction that can be recovered as is, or it can be further converted to lithium hydroxide, etc., to form pure hydroxide crystals.

[0041] A further option for lithium recovery is to use solvent extraction, followed by further conversion or crystallization. The advantage of this procedure is a higher lithium recovery rate.

[0042] The liquid fraction obtained when reacting lithium with a carbonate still contains lithium that can be separately recovered. This liquid fraction is thus further reacted with a phosphate reagent, and optionally another precipitation reagent, to precipitate the lithium remaining therein as a lithium phosphate precipitate. After separating at least a portion of the precipitate from the remaining waste liquid, it can be recycled to the leaching step by mixing it with the pretreated black aggregate. Also, a portion of the precipitated lithium phosphate can be directed to the above-described steps for lithium recovery, and the phosphate, together with the carbonate, can be reacted with lithium hydroxide.

[0043] The phosphate reagent used above can be selected from any phosphate of an alkali metal or alkaline earth metal. However, sodium phosphate (Na3PO4) is preferred because it does not introduce new cations into the reaction mixture and has appropriate reactivity.

[0044] For example, the precipitation of lithium in the lithium-containing liquid fraction obtained when reacting lithium with its carbonate is typically carried out at a temperature of 50 to 90 °C, preferably 70 to 90 °C. The pH is typically maintained at 4 or higher, preferably 7 or higher.

[0045] For the liquid fraction obtained when reacting lithium with its carbonate, the same conditions and reagents used here can also be used for the washing solution obtained from the pretreatment step, and optionally, it can also be treated for lithium recovery by precipitation to lithium phosphate.

[0046] Nickel recovery is also carried out on the leaching solution, preferably after separation of the initial metal fraction, typically simultaneously with, or immediately after, optional cobalt recovery, more preferably after cobalt recovery, and most preferably before the above-described lithium recovery. Similarly, nickel recovery is preferably carried out after optional manganese recovery.

[0047] The nickel recovery can be carried out, for example, using solvent extraction (SX), which produces a fairly pure nickel sulfate solution (NiSO4). This solution can optionally be further purified, for example, by ion exchange (IX), and then crystallization is carried out, or precipitation into a hydroxide or carbonate, or a sulfate solution can be used as is without crystallization or precipitation, for example, in the preparation of a new cathode material. The optional solvent extraction for nickel recovery is most suitably carried out using an extraction chemical having a carboxylic acid functional group, and an example of a commercially available product of a suitable extraction chemical is Versatic TM 10, which is neodecanoic acid.

[0048] The cobalt recovery is also preferably carried out in the leaching solution after the separation of the initial metal fraction, typically simultaneously with or immediately before the nickel recovery, more preferably before the nickel recovery, and most preferably also before the lithium recovery. Similarly, it is preferred to carry out the cobalt recovery after the optional manganese recovery.

[0049] The preferred option for the cobalt recovery is solvent extraction (SX), which produces a fairly pure cobalt sulfate solution (CoSO4). This solution can optionally be further purified, for example, by ion exchange (IX), and then crystallization or precipitation into a hydroxide or carbonate can be carried out, or the sulfate solution can be used as is without crystallization or precipitation, for example, in the preparation of a new cathode material. The optional solvent extraction for cobalt recovery is most suitably carried out using an extraction chemical having a carboxylic acid functional group such as a phosphinic acid functional group, and an example of a suitable extraction chemical is Cyanex TM 272, which is also known as trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate.

[0050] In one alternative approach to proceeding with the metal separation step, as shown above, for example by solvent extraction, cobalt and nickel can be simultaneously recovered from the leach solution to produce a sulfate solution, optionally followed by further purification by ion exchange (IX), or precipitation to hydroxides or carbonates. Alternatively, this sulfate solution can be used directly, without causing crystallization or precipitation, for example in the preparation of a new cathode material.

[0051] According to one embodiment of the present invention, the metal separation step includes a step of recovering manganese from the leach solution, and the recovery of manganese is also carried out after the separation of the initial metal fraction. Preferably, manganese is recovered before the recovery of nickel or optional cobalt recovery, and most preferably, it is recovered before any of nickel, cobalt or lithium is recovered.

[0052] Options for said manganese recovery include solvent extraction, precipitation, and crystallization, or solvent extraction followed by subsequent precipitation or crystallization. One particularly preferred option is to utilize oxidative precipitation using sulfur dioxide (SO2) and air to form manganese dioxide (MnO2).

[0053] The method of the present invention can be carried out in any suitable apparatus or facility equipped with the units and equipment necessary to carry out the steps of the method.

[0054] In one embodiment of the present invention, the above-described method is carried out using the facility of FIG. 1, which facility includes the following units, namely, - One or more pretreatment units 1 for separating the fraction containing non-metallic components from the black aggregate and recovering the pretreated black aggregate containing the anode material and the cathode material, preferably intended to be carried out via a suitable connection to the downstream leaching unit 2, the pretreatment unit 1 and, - One or more leaching units 2 for dissolving the metal of the pretreated black aggregate combined with the regenerated lithium precipitate and recovering the leaching solution containing the dissolved metal, preferably intended to be led through a suitable connection to a downstream separation unit 3, and at least one leaching unit 2 is in the form of an acid leaching unit having an inlet 211 for sulfuric acid and a possible extractant, the leaching unit 2, and, - A metal separation unit 3 for separating an initial fraction of the metal material from the leaching solution and recovering a main fraction containing at least nickel and lithium as a product fraction, with a lithium recovery unit 36 located downstream of a nickel recovery unit 35, and the lithium recovery unit 36 includes the following sub-units, the metal separation unit 3, and the sub-units are the following units, namely · A unit 361 for reacting lithium to solid lithium carbonate, from which waste liquid is separated and further conveyed to the next step, the unit 361, · A reaction unit 362 for reacting the waste liquid with a phosphate reagent, in which the remaining lithium is precipitated to lithium phosphate precipitate, separated from the remaining waste liquid, and further conveyed through the following, the reaction unit 362, · A recycle line 363 for sending at least a part of the thus obtained lithium precipitate to the acid leaching unit 2, which includes, the metal separation unit 3 and, is provided with.

[0055] In one embodiment of the present invention having various options shown in FIGS. 2A and 2B, the pretreatment unit 1 includes a washing unit 11 or a heating unit 12, or both, for removing non-metal components such as organic compounds from the black aggregate, and the heating unit 12 is most preferably selected from a pyrolysis unit 121 or an evaporation unit 122. The optional washing unit 11 preferably further has a water inlet.

[0056] In a preferred embodiment of the present invention, as shown in FIG. 3, the pretreatment unit 1 includes at least a cleaning unit 11 for separating the fraction of the non-metallic material from the black aggregate into the cleaning solution. Typically, it includes a separation subunit for separating the formed lithium precipitate from the remaining solution. The cleaning unit 11 includes the following units, namely, - A reaction unit 111 for reacting the used cleaning solution containing the separated fraction of the non-metallic material with a phosphate reagent to precipitate the lithium therein as lithium phosphate. Typically, the reaction unit 111 includes a separation subunit for separating the formed lithium precipitate from the remaining solution, and - A recycle line 112 for transporting the obtained lithium phosphate precipitate to the leaching unit 2 and combining it with the pretreated black aggregate. It includes.

[0057] Typically, the leaching unit 2 composed only of the acid leaching unit 21 preferably includes an inlet 211 for sulfuric acid and the extractant, and temperature adjusting means 212 that can incorporate either heating or cooling as shown in FIGS. 2 to 4.

[0058] The metal separation unit 3 preferably includes several subunits. All subunits typically include additional subunits necessary to carry out the reactions they are intended for, such as solvent extraction units, ion exchange units, precipitation units, electro-winning units, cleaning units or solid / liquid separation units), recycle lines, inlets and outlets.

[0059] Preferably, in addition to the nickel recovery unit 35 and the lithium recovery unit 36, the metal separation unit 3 includes one or more additional units 33, 34 for recovering manganese ions and cobalt ions, as shown in FIG. 4. All of these units for recovering the main fraction preferably precede one or more units 31, 32 for separating the initial fraction of the metal material from the leaching solution, and these units 31, 32 most preferably include at least one solvent extraction unit.

[0060] When copper is separately recovered within the facility, the copper recovery unit 31 is preferably located upstream of the other unit 32 for separating the initial metal fraction from the leaching solution.

[0061] To carry out the separation and recovery, various types of units and equipment can be utilized, for example, additional leaching or washing units, solvent extraction units, precipitation units, ion exchange units, and electro-winning units, etc. However, solvent extraction units are preferred. In particular, it is preferred to utilize at least one solvent extraction unit for the separation of the initial metal fraction. More preferably, there is a solid separation unit before the solvent extraction, and optionally a precipitation unit for such impurities before that.

[0062] Thus, the units 33, 34, 35, 36 for recovering the main fraction of the metal material include units for recovering at least nickel ions and lithium ions, and can be arranged in any suitable order, usually recovering nickel before lithium.

[0063] In a preferred embodiment of the present invention, any units 34, 35 for recovering cobalt and nickel are located upstream of the unit 36 for recovering lithium.

[0064] In another preferred embodiment of the present invention, a unit 33 for recovering manganese is included in the facility and is located upstream of any of the units 34, 35, 36 for recovering cobalt, nickel, and lithium.

[0065] In one alternative method of selecting the metal separation unit 3 and the facility, cobalt and nickel can be recovered in the same unit 34 / 35.

[0066] As described above, the lithium recovery unit 36 includes the following sub-units, namely, · A unit 361 for reacting lithium with lithium carbonate, typically followed by a solid-liquid separation sub-unit for separating the carbonate-containing solid from the waste liquid, the unit 361, · A reaction unit 362 for reacting the waste liquid with a phosphate reagent and optionally another precipitation reagent, as a result of which the lithium remaining therein is precipitated as a lithium phosphate precipitate, usually followed by a solid-liquid separation sub-unit for separating the lithium precipitate from the remaining waste liquid, the reaction unit 362, and · A recycle line 363 for recycling at least a part of the thus obtained lithium precipitate to the acid leaching unit 2 and including.

[0067] Furthermore, as shown in FIG. 4, the lithium recovery unit 36 can also include a sub-unit 364 for reacting the lithium-containing solid obtained after reacting lithium with lithium carbonate with lithium hydroxide, and then the lithium hydroxide can be crystallized to obtain lithium hydroxide crystals. Also, a part of the precipitated lithium phosphate can be led to the reaction sub-unit 364 and reacted to form lithium hydroxide.

[0068] The disclosed embodiments of the present invention are not limited to the specific structures, process steps, or materials disclosed herein, but are to be extended to their equivalents, as would be recognized by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0069] Throughout this specification, reference to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. For example, when referring to a numerical value using terms such as “about” or “substantially,” the exact numerical value is also disclosed.

[0070] As used herein, a plurality of items, structural elements, components, and / or materials may, for convenience, be presented in a common list. However, these lists should be construed as if each member of the list were individually identified as a separate and unique member. In addition, various embodiments and examples of the present invention may be referred to herein with alternative of their various components. Such embodiments, examples, and alternatives are not to be construed as virtual equivalents of each other, but rather as separate and autonomous representations of the present invention.

[0071] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0072] The above-described embodiments illustrate the principles of the present invention in one or more specific applications. However, it will be apparent to those skilled in the art that numerous changes in form, usage, and details of implementation can be made without exercising inventive faculty and without departing from the principles and concepts of the present invention.

[0073] The following non-limiting examples are intended merely to illustrate the advantages obtained in embodiments of the present invention.

Example

[0074] (Example) Leaching of Lithium Precipitated Phosphate (Li3PO4) 30.5 g of a solid sample containing lithium phosphate (Li3PO4) with a composition of 15.4% Li and 22.1% P was leached at a temperature of 80 °C in a stirred reactor. The lithium phosphate was pulped with 0.9 L of an 80 g / L sulfuric acid solution and stirred for 2 hours.

[0075] Analysis of the leach solution showed that it contained 5140 mg / L of Li and 7540 mg / L of P at pH 1.1. As shown in Table 1 below, the calculated leaching yield of lithium was 98.5%.

[0076]

Table 1

[0077] In the next step, lithium phosphate was precipitated. 1.4 L of the above-described leach solution of the black aggregate at 40 °C was placed in a stirred reactor, and subsequently a solution containing 500 g / L of NaOH was added stepwise to raise the pH from 3 to 5 to remove phosphate, iron, and aluminum. Efficient removal of phosphate was observed, as indicated by the decrease in the phosphate content of the solution in Table 2 below.

[0078]

Table 2

Industrial Applicability

[0079] The present method and the equipment suitable for use in said method can be used to replace the conventional alternative means for recovering metals from the black aggregate obtained from lithium-ion batteries.

[0080] In particular, the method and equipment of the present invention provide an economic and efficient procedure for recovering at least nickel and lithium, and optionally cobalt and manganese, in good yields from such battery materials. The yield of lithium is further improved by recovering and recycling the lithium obtained from one or more waste liquids of the present method.

Explanation of Signs

[0081] As shown in FIGS. 1 to 4, according to one or more embodiments of the present invention, the following units can be included in the equipment of the present invention, namely, 1 A pretreatment unit, including or consisting of the following, namely, 11 A cleaning unit, which usually has a solid-liquid separation subunit, and optionally the following, namely, 111 A reaction unit, which usually has a solid-liquid separation subunit, and 112 A recycling line equipped with, 12 A heating unit, for example, in the following forms, namely, 121 A pyrolysis unit 122 An evaporation unit consisting of, 2 A leaching unit, which usually has a solid-liquid separation unit, and the leaching unit includes or consists of the following, namely, 21 A leaching unit, 211 An inlet for an acid and a possible extractant, and 212 A temperature adjustment means, including, 3 A metal separation unit, including the following, namely, 31 An optional unit for recovering metal materials, and 32 A unit for separating the initial fraction of the metal material An optional unit for recovering 33 manganese, an optional unit for recovering 34 cobalt, and a unit for recovering 35 nickel, and a unit for recovering 36 lithium, namely, a unit for reacting 361 lithium to lithium carbonate, usually equipped with a solid-liquid separation subunit, said unit, and a unit for reacting 362 waste liquid with a phosphate reagent, usually equipped with a solid-liquid separation subunit, said unit, and a recycle line, and an optional unit for reacting 364 lithium carbonate to a hydroxide are included.

Claims

1. A method for extracting metals from a black aggregate of a lithium-ion battery, wherein the black aggregate contains a negative electrode material and a positive electrode material of the battery, and the positive electrode material contains lithium and nickel, the method comprising the following steps, namely, a) One or more pretreatment steps in which a fraction containing non-metallic material is separated from the black aggregate and a pretreated black aggregate containing the negative and positive electrode materials is recovered, said pretreatment step; and b) One or more leaching steps carried out on a metal-containing leaching feed consisting of the pretreated black aggregate combined with recycled lithium precipitate, said leaching step including an acid leaching step carried out in a solution containing sulfuric acid, whereby the metals of the leaching feed are dissolved and a leaching solution containing the dissolved metals is recovered, said leaching step; and c) A metal separation step in which an initial fraction of the metal material is separated from the leaching solution and a main fraction containing at least nickel and lithium is recovered, whereby the fraction containing lithium is recovered after the nickel fraction has been recovered, the recovery of the fraction containing lithium comprising the following steps, namely, iii) Reacting lithium to lithium carbonate, and then, iv) Separating the solid from the fluid, - The solid containing lithium is either recovered as such or reacted to form further lithium products, whereas, - Reacting the waste liquid with a phosphate reagent to precipitate the remaining lithium therein as a lithium phosphate precipitate, and - Recycling at least a part of the obtained lithium precipitate to the acid leaching step, including the step of separating the solid from the fluid, said metal separation step; and A method comprising.

2. The method according to claim 1, in the method used for extracting metal from a black aggregate, wherein the positive electrode material contains lithium and nickel, and one or more of cobalt, manganese, and aluminum in the form of an oxide.

3. In the method according to claim 1 or 2, wherein the pretreatment step includes one or both steps of washing or heating, and the heating is carried out to provide pyrolysis or evaporation.

4. In the method according to any one of claims 1 to 3, the pretreatment step is carried out to separate a non-metallic component containing an organic compound from the black aggregate, and as a result, a pretreated black aggregate containing less than 3% by weight, preferably less than 1.5% by weight of the organic compound is obtained.

5. In the method according to any one of claims 1 to 4, the pretreatment step is the following steps, namely, - a step of washing the black aggregate with an aqueous solution or an organic solvent to separate a fraction of non-metallic material from the black aggregate with a washing solution; - a step of reacting the used washing solution containing the separated fraction of non-metallic material with a phosphate reagent to precipitate lithium therein as lithium phosphate; and - a step of separating the lithium phosphate precipitate from the remaining washing solution and combining it with the pretreated black aggregate to be conveyed to the next leaching step. The method including.

6. In the method according to any one of claims 1 to 5, the acid leaching is carried out in a single step by dispersing the pretreated black aggregate mixed with the recycled lithium precipitate in a solution containing an acid and an optional extractant.

7. In the method according to any one of claims 1 to 6, the step of recovering the main fraction of the metal material precedes the step of separating the initial fraction of the metal material from the leaching solution.

8. The method according to any one of claims 1 to 7, wherein the initial fraction is carried out to contain phosphate ions and at least one of iron ions, aluminum ions, calcium ions and fluoride ions.

9. In the method according to any one of claims 1 to 8, at least one of the steps for separating the initial fraction of the metal material from the leaching solution is carried out as solvent extraction, intended to remove impurities containing iron or aluminum from the leaching solution, removing solid impurities, and optionally solid separation precedes to enhance the selectivity of the solvent extraction, and the solid separation optionally precedes the precipitation of such impurities.

10. In the method according to any one of claims 1 to 9, at least one of the steps for separating the initial fraction of the metal material from the leaching solution is a precipitation intended to remove impurities containing iron or aluminum and phosphates from the leaching solution, and solvent extraction follows.

11. In the method according to any one of claims 1 to 10, the metal separation step includes one step for recovering copper from the leaching solution and is carried out before other separation or recovery of the metal material.

12. In the method according to any one of claims 1 to 11, the recovery of the main fraction of the metal material includes steps for recovering at least one of manganese and cobalt in addition to nickel and lithium.

13. In the method according to any one of claims 1 to 12, any step for recovering manganese, cobalt or nickel is carried out before recovering lithium.

14. In the method according to any one of claims 1 to 13, the lithium-containing solid obtained after reacting lithium with a lithium carbonate product is further reacted with lithium hydroxide, and then the lithium-containing solid can be crystallized to obtain lithium hydroxide crystals.

15. The method according to any one of claims 1 to 14, wherein nickel is recovered simultaneously with cobalt or separately.

16. The method according to any one of claims 1 to 15, wherein nickel is recovered after the initial fraction of the metal material is separated from the leaching solution, and these initial fractions also contain phosphates of lithium precipitates recycled to the leaching step.

17. The method according to any one of claims 1 to 16, wherein nickel is recovered by solvent extraction to produce a nickel sulfate solution (NiSO₄) using an extraction chemical having a carboxylic acid functional group, and one commercial example of a suitable said extraction chemical is VersaticTM 10, which is neodecanoic acid.

18. The method according to any one of claims 1 to 17, wherein nickel is recovered by solvent extraction to produce a nickel sulfate solution, and the solution is used as it is, or further purified by ion exchange and optional crystallization, or precipitated into a hydroxide or carbonate.

19. The method according to any one of claims 1 to 18, wherein the metal separation step includes a step of recovering cobalt from the leaching solution, and the recovery of cobalt is carried out simultaneously with or immediately before the recovery of nickel.

20. The method according to any one of claims 1 to 19, wherein the metal separation step includes a step of recovering cobalt from the leaching solution, and the cobalt recovery is carried out by solvent extraction to produce a cobalt sulfate solution (CoSO ４ ), and it is preferable to use an extraction chemical having a carboxylic acid functional group such as a phosphinic acid functional group. An example of a suitable extraction chemical is Cyanex known also as trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl)phosphinate. TM 272.

21. In the method according to any one of claims 1 to 20, the metal separation step includes a step of recovering cobalt from the leaching solution, and the recovery of the cobalt is carried out by solvent extraction to produce a cobalt sulfate solution, and the solution is used as it is, or further purified by ion exchange and optional crystallization, or precipitated as a hydroxide or carbonate.

22. In the method according to any one of claims 1 to 21, the metal separation step is carried out before any one of cobalt, nickel or lithium is recovered, and includes a step of recovering manganese from the leaching solution, and the recovery of manganese is carried out by solvent extraction or precipitation, or by solvent extraction following precipitation.

23. In the method according to any one of claims 1 to 22, the phosphate reagent used to precipitate lithium phosphate is selected from any phosphate of an alkali metal or an alkaline earth metal.

24. In the method according to any one of claims 1 to 23, the phosphate precipitation is carried out at a temperature of 50 to 90 °C, preferably 70 to 90 °C.

25. In the method according to any one of claims 1 to 24, the phosphate precipitation is carried out at a pH of 4 or higher, preferably 7 or higher.

26. Equipment for extracting metals from the black aggregate of a lithium-ion battery, wherein the black aggregate contains the negative electrode material and the positive electrode material of the battery, and the positive electrode material contains lithium and nickel, comprising the following units, namely, - One or more pretreatment units (1) for separating a fraction containing non-metallic components from the black aggregate and recovering the pretreated black aggregate containing the negative electrode material and the positive electrode material; - One or more leaching units (2) for dissolving the pretreated black mass metal combined with recycled lithium precipitate and recovering a leaching solution containing the dissolved metal, wherein at least one leaching unit (2) is in the form of an acid leaching unit (21) having an inlet (211) for sulfuric acid and a possible extractant, the leaching unit (2) and - A metal separation unit (3) for separating an initial fraction of the metal material from the leaching solution and recovering a main fraction containing at least nickel and lithium, wherein a lithium recovery unit (36) is located downstream of a nickel recovery unit (35), and the lithium recovery unit (36) includes the following sub-units, the metal separation unit (3), and the sub-units are the following units, namely ・ A unit (361) for reacting lithium to solid lithium carbonate, from which waste liquid can be separated and further conveyed next, the unit (361), ・ A reaction unit (362) for reacting the waste liquid with a phosphate reagent, as a result of which lithium remaining therein is precipitated into lithium phosphate precipitate, which can be separated from the remaining waste liquid and further transported via, the reaction unit (362), ・ A recycle line (363) to the acid leaching unit (2) for recovering at least a part of the lithium precipitate thus obtained, which includes. The metal separation unit (3) and An equipment comprising.

27. In the equipment according to claim 26, the pretreatment unit (1) includes a washing unit (11) and / or a heating unit (12) for removing non-metallic components containing organic compounds from the black aggregate, and the heating unit (12) is selected from a pyrolysis unit (121) or an evaporation unit (122), an equipment.

28. In the equipment according to claim 26 or 27, the pretreatment unit (1) is the following unit, namely - A cleaning unit (11) for separating a fraction of non-metallic material from a black aggregate into a cleaning solution, typically comprising a separation subunit for separating the formed lithium precipitate from the remaining solution, said cleaning unit (11); - A reaction unit (111) for reacting a used cleaning liquid containing a separated fraction of non-metallic material with a phosphate reagent to precipitate lithium therein as lithium phosphate, typically comprising a separation subunit for separating the formed lithium precipitate from the remaining solution, said reaction unit (111); and - A recycling line (112) for transporting the resulting lithium phosphate precipitate to a leaching device (2) and combining it with the pretreated black aggregate; An installation comprising.

29. The installation according to any one of claims 26 to 28, wherein the leaching unit (2) comprises means (212) for regulating the temperature.

30. The installation according to any one of claims 26 to 29, wherein the metal separation unit (3) comprises one or more units (33, 34, 35, 36) for recovering the main fraction of the metal material, including at least a unit (35) for recovering nickel and a unit (36) for recovering lithium ions, and one or more upstream units (31, 32) for separating the initial metal fraction from the leaching solution precede, and the initial fraction comprises phosphate ions and at least one of iron, aluminum, calcium and fluoride ions.

31. The installation according to any one of claims 26 to 30, wherein the lithium recovery unit (36) comprises a subunit (364) for reacting the lithium-containing solid obtained after reacting lithium with lithium carbonate with lithium hydroxide, and lithium hydroxide crystals can be obtained by crystallization.

32. A method according to any one of claims 1 to 25, implemented using an installation according to any one of claims 26 to 31.

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