Methods for recovering metals from electronic waste

Abstract

Disclosed herein is a method for recovering metals from an alkaline leaching leachate of electronic waste, wherein the leachate contains Cu, Li, and Mn ions, and the method comprises recovering Mn from the leachate, recovering Cu from the leachate after the step of recovering Mn from the leachate, and recovering Li from the leachate after the step of recovering Cu from the leachate.

Description

[Technical Field]

[0001] The present invention generally relates to a method for recovering lithium and optionally other transition metals from waste electronic materials comprising at least copper and one or more lithium salts, specifically, the waste electronic material being a waste lithium-ion battery. [Background technology]

[0002] The amount of discarded electronic equipment used worldwide, particularly rechargeable lithium-ion batteries, has increased rapidly in recent years and is expected to expand further with the emerging markets for electric vehicles and large-scale energy storage. As demand for electronic devices, especially those using lithium-ion batteries, increases, so does the demand for the metal / metal oxide components used in these devices. The rapid increase in demand for some of these metals, such as cobalt, is putting pressure on the sustainable supply of such resources. This is causing a rapid increase in the cost of such metals.

[0003] Little attention has been paid to the development of processes for the recovery and recycling of various components of modern electronic devices, such as batteries. In the case of batteries, this is mainly due to the relatively small amount of lithium-ion batteries available for recycling and the relatively high cost of the typical pyrochemical and humidification processes used to achieve recovery. As the demand for lithium-ion batteries continues to increase, so does the amount of used lithium-ion batteries that can be recycled. Low-cost and efficient recycling processes are needed, especially for more complex metal / metal oxide components. The following discussions mainly concern lithium-ion batteries, but they are applicable to a variety of electronic devices as they also incorporate a range of different metal compounds.

[0004] The composition of lithium-ion batteries has evolved considerably in recent years. While several battery recirculation processes have been developed, these are primarily limited to the recovery of specific metals from particular types of batteries or feed sources. For example, early batteries were primarily lithium-cobalt, and the focus of recovery methods was on cobalt recovery. As lithium demand increased, recovery methods shifted to the recovery of both cobalt and lithium. As battery technology further advanced, cathodes incorporated other metals such as manganese, nickel, aluminum, iron, and phosphorus. Methods used to recover lithium and cobalt are not suitable for recovering other metals, nor are they suitable for different battery chemistry.

[0005] As the use of lithium-ion batteries increases, so does the amount of spent lithium-ion batteries available for recycling. However, the supply of spent lithium-ion batteries includes many different types of batteries. The suitability of recovery methods for only a single battery type presents significant problems for the commercialization of such processes. Specifically, such methods require one or more sorting and pretreatment steps. Given this, it is necessary to develop processes for recovering various metals from various different types of lithium-ion batteries.

[0006] Most developments in battery recycling processes involve dissolving metal components in an acidic medium. This is a non-selective leaching process in which most of the metals contained in the battery dissolve. Batteries contain significant amounts of various non-valuable metals such as iron, manganese, and aluminum. Some batteries may also contain phosphorus. If these non-valuable metals and phosphorus are not removed before leaching, the consumption of acid will be high. Therefore, the pretreatment process needs to separate iron and aluminum from valuable metal components such as cobalt, nickel, copper, and lithium. Doing so reduces the recovery of these valuable metals because the separation achieved in these pretreatment processes is not 100% efficient.

[0007] It is desirable to provide a method for recovering metals, particularly lithium, from waste electronic devices such as batteries.

[0008] An object of the present invention is to address one or more drawbacks of the prior art and / or to provide a useful alternative. [Overview of the project]

[0009] In a first aspect of the present invention, a method is provided for recovering metals from an alkaline leaching leachate of electronic waste, wherein the leaching leachate contains Cu, Li, and Mn ions, and the method is as follows: To recover Mn from the leachate, After the step of recovering Mn from the leachate, the Cu is recovered from the leachate, The method includes recovering Li from the leachate after recovering Cu from the leachate.

[0010] In one embodiment, the leachate further contains Co ions, and the method further includes recovering Co from the leachate after the step of recovering Cu from the leachate and before the step of recovering Li from the leachate.

[0011] A second aspect of the present invention provides a method for recovering metals from an alkaline leaching leachate of electronic waste, wherein the leaching leachate contains Cu, Li, Ni, and Mn ions, and the method is as follows: To recover Mn from the leachate, After the step of recovering Mn from the leachate, Cu and Ni are recovered from the leachate. The method includes recovering Cu and Ni from the leachate, followed by recovering Li from the leachate.

[0012] In one embodiment, the leachate further contains Co ions, and the method further includes recovering Co from the leachate after the step of recovering Cu and Ni from the leachate, and before the step of recovering Li from the leachate.

[0013] In one embodiment, Cu and Ni are recovered simultaneously. In a first alternative embodiment, Cu is recovered before Ni. In a second alternative embodiment, Ni is recovered before Cu.

[0014] In one embodiment of the first or second aspect (and / or multiple embodiments thereof), the leachate is substantially free of Fe and / or Al ions. Preferably, Fe and / or Al are present in the leachate at a concentration of 100 mg / L or less each. More preferably, Fe and / or Al are present in the leachate at a concentration of 80 mg / L or less each. Most preferably, Fe and / or Al are present in the leachate at a concentration of 60 mg / L or less each each.

[0015] In one embodiment of the first or second aspect (and / or multiple embodiments thereof), prior to the step of recovering Mn, the leachate is Cu 2+ Mn 2+ , and Li + It contains Cu, Li, and Mn ions in various forms. In forms where Co and / or Ni are present, the leachate contains Co before the step of recovering Mn. 2+ and Ni 2+ Contains Co and / or Ni in various forms.

[0016] In one embodiment of the first or second aspect (and / or multiple embodiments thereof), the method further comprises leaching electronic waste with an alkaline leaching solution containing at least ammonium sulfate and ammonia to provide a leachate.

[0017] In one embodiment of the above embodiment, the electronic waste includes, consists of, or is essentially composed of one or more types of lithium-ion batteries, such as lithium nickel manganese cobalt oxide (NMC) batteries. Preferably, the batteries are in the form of lithium-ion battery fragments. In an alternative embodiment, the electronic waste includes a mixture of one or more types of lithium-ion batteries and other electronic waste, such as printed circuit boards.

[0018] In one form of the above embodiment, the electronic waste is LiNi w Co x Al y Mn z O2, where w + x + y + z = 1, and / or LiNi x Mn y Co 1-x-y O2, where 0 ≤ x + y ≤ 1, and includes, consists of, or consists essentially of one or more types of lithium compounds selected from the group consisting of.

[0019] In one embodiment of the first or second aspect (and / or multiple embodiments thereof), the step of recovering Mn from the leachate is treating the leachate with an oxidizing agent to form a Mn precipitate; separating the Mn precipitate from the leachate.

[0020] In one form of the above embodiment, the oxidizing agent is selected from the group consisting of air, hydrogen peroxide, and / or hypochlorite.

[0021] In one form of the above embodiment, the Mn precipitate is a manganese oxide selected from the group consisting of Mn2O3, Mn3O4, and / or MnO2. It is preferred that the Mn precipitate is not Mn(OH)2 and / or does not contain Mn(OH)2.

[0022] In one embodiment of the first or second aspect (and multiple embodiments thereof), the step of recovering Li from the leachate is crystallizing ammonium lithium sulfate from the leachate; separating the crystallized ammonium lithium sulfate from the leachate.

[0023] In one form of the above embodiment, the method further includes thermally decomposing the crystallized ammonium lithium sulfate to form a gas containing ammonia and sulfur oxides, and solid lithium sulfate.

[0024] In one embodiment (and / or multiple embodiments thereof) of the first or second embodiment prior to the step of recovering Li from the leachate, the leachate is treated such that the leachate is low in ammonia, Cu, Ni, Co, and Mn, and / or the leachate is substantially free of ammonia, Al, Cu, Fe, Ni, Co, or Mn.

[0025] In one embodiment (and / or multiple embodiments thereof) of the first or second embodiment prior to the step of recovering Li from the leachate, the leachate is treated so that it contains ammonia, Cu, Ni, Co, and Mn at concentrations of 100 mg / L or less each. Preferably, the concentration is 80 mg / L or less each. Most preferably, the concentration is 60 mg / L or less each.

[0026] In one embodiment of the first or second aspect (and several embodiments thereof), the step of recovering Cu ions from the leachate is performed using a solvent extraction process, and the solvent extraction process is To adsorb Cu ions onto the extractant, the leachate is brought into contact with the extractant to form a Cu-packed extractant. This includes separating the Cu-filled extractant from the leachate.

[0027] In one embodiment of the above, the method further includes stripping Cu ions from a Cu-packed extractant using a stripping agent such as sulfuric acid.

[0028] In one embodiment (and / or more embodiments) of the second aspect, the step of recovering Cu and Ni ions from the leachate includes recovering Cu and Ni ions simultaneously using a solvent extraction process, the solvent extraction process is In order to adsorb Cu and Ni ions onto the extractant, the leachate is brought into contact with the extractant to form a Cu, Ni-packed extractant. This includes separating Cu and Ni-packed extractants from the leachate.

[0029] In one embodiment of the above embodiment, the method further comprises stripping Cu and Ni ions from a Cu, Ni-packed extractant using a stripping agent such as sulfuric acid, wherein the Ni ions are selectively recovered at a first stripping agent concentration, and the Cu ions are subsequently recovered at a second stripping agent concentration, the first stripping agent concentration being less than the second stripping agent concentration.

[0030] In one embodiment of the first aspect (and / or more embodiments thereof), prior to the step of recovering Cu, the method treats the leachate with an oxidizing agent to recover Co 2+ From Co 3+ This further includes oxidizing Co ions. Preferably, the oxidizing agent is selected from the group consisting of air, hydrogen peroxide, and / or hypochlorite.

[0031] In one embodiment (and / or more embodiments) of the second aspect, prior to the step of recovering Cu and Ni, the method treats the leachate with an oxidizing agent to recover Co 2+ From Co 3+ This further includes oxidizing Co ions. Preferably, the oxidizing agent is selected from the group consisting of air, hydrogen peroxide, and / or hypochlorite.

[0032] In one embodiment of the first or second aspect (and / or multiple embodiments thereof), the step of recovering Co from the leachate is: The leachate is treated with a precipitate to form a Co precipitate, This includes separating the Co precipitate from the leachate.

[0033] A suitable precipitate is a sulfide such as hydrogen sulfide. The Co precipitate (in this example, cobalt sulfide) can then be recovered from the combined leachate using any solid-liquid separation process commonly known to those skilled in the art, such as filtration.

[0034] In one embodiment of the first or second aspect (and / or multiple embodiments thereof), the leachate contains ammonium sulfate and / or ammonia. Preferably, the leachate contains ammonia and ammonium sulfate in a ratio of about 1:2 to about 1:20. In one aspect of this aspect, the leachate additionally contains ammonium chloride.

[0035] In one embodiment (and / or multiple embodiments thereof) of the first or second aspect, The exudate has an initial pH in the range of approximately 8.5 to 10.5, and / or During one or more recovery steps, or each of them, the leachate has a pH in the range of approximately 8.5 to 10.5.

[0036] In one embodiment (and more embodiments thereof) of the first or second aspect, one of the following applies: The leachate has a Cu:Mn ratio of approximately 0.5:1 to approximately 2:1, or The leachate has a Cu:(Mn+Co) ratio of approximately 0.5:1 to approximately 2:1, or The leachate has a Cu:(Mn+Ni) ratio of approximately 0.5:1 to approximately 2:1, or The leachate has a Cu:(Mn+Co+Ni) ratio of approximately 0.5:1 to approximately 2:1.

[0037] In one embodiment, the leachate is substantially free of added organic compounds. That is, the leachate may contain organic compounds resulting from the leaching of electronic waste, but it does not contain any further added organic compounds. For example, the leachate does not contain monomers, oligomers, polymers, surfactants, organolixivants, organic acids, organometallic compounds, etc.

[0038] In one embodiment, the leachate is substantially free of biomaterial. For example, the leachate does not contain biomatter from vegetables, fruits, or animals.

[0039] No reference to prior art in this specification constitutes an endorsement or implied that the prior art forms part of the common general knowledge in any jurisdiction, or that the prior art can be reasonably expected to be understood, considered relevant, and / or combined with other prior art by those skilled in the art.

[0040] As used herein, unless the context requires otherwise, the term “comprise,” and its variations, such as “comprising,” “comprises,” and “comprised,” are not intended to exclude any further additives, ingredients, elements, or steps.

[0041] Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraph will become apparent from the following description and are given by reference to the accompanying drawings, for example. [Brief explanation of the drawing]

[0042] [Figure 1] This is a process flow diagram illustrating a method of the present invention according to another embodiment of the present invention. [Modes for carrying out the invention]

[0043] The present invention relates to a method for recovering valuable metals from leachates obtained from alkaline leaching of electronic waste (and, in particular, from fragments of lithium-ion batteries). The present invention is particularly applicable to the recovery of Cu, Li, and Mn from leachates containing ions of these metals. However, the additional recovery of Co and Ni from leachates additionally containing ions of these metals is also intended.

[0044] In general, the metal recovery process of the present invention is for recovering metals from alkaline leachates of electronic waste. In particular, it uses a leachate containing ammonium sulfate and, optionally, ammonia and / or ammonium chloride. In the leachate, elemental copper is oxidized to copper ions, providing an electron source that acts as a reducing agent, thereby generating soluble lithium ions from lithium-containing salts. Transition metals such as cobalt, manganese, and nickel present in the electronic waste are similarly reduced to soluble ions, for example, as components of lithium-containing salts or as metal oxides. Various soluble metal ions, particularly lithium, can be selectively recovered as products. Ammonium sulfate can also be recovered and reused for further leaching.

[0045] The inventors have found that the order of metal recovery from the leachate is important in order to recover high-purity products while minimizing operating costs. In particular, the inventors have found that in leachates containing Cu, Li, and Mn, it is important that Mn is recovered first, followed by Cu, and finally Li.

[0046] Co and Ni are transition metals that are also present in many types of electronic waste, such as various types of lithium-ion batteries. Given this, ideally, this method can be adapted to additionally recover these metals. When the leachate contains Ni, the inventors have found that Ni can be best removed after the recovery of Mn and before, after, or simultaneously with, Cu. When the leachate contains Co, the inventors have found that it can be best removed after the recovery of Mn, Cu, and Ni (if present), but before the recovery of Li.

[0047] More specifically, the inventors have found that Mn ions can be recovered by an oxidation step in which Mn ions are oxidized to manganese oxides such as Mn2O3, Mn3O4, and / or MnO2 (not MnO). Suitable oxidizing agents include air, hydrogen peroxide, and / or hypochlorite. Air is a preferred oxidizing agent. These manganese oxides are insoluble and therefore form a precipitate that can be separated from the leachate as a high-purity solid product using standard solid-liquid separation processes, as is known to those skilled in the art.

[0048] During this oxidation process, Co 2+ If ions are present, these are advantageous, Co 3+ The ions are oxidized, thereby preventing the co-recovery of Co ions during the recovery of Cu and Ni (if present), as will be discussed below. To prevent co-precipitation of CoO and Mn, the leachate preferably contains ammonia.

[0049] Ammonia forms a stable soluble sulfate complex with Co ions, and therefore, instead of Co ions during this oxidation step, 2+ From Co 3+ This promotes oxidation to prevent the precipitation of CoO. Ideally, sufficient ammonia should be present to provide a pH in the range of 9–10. Ammonia may be present in sufficient quantities in the leachate as a result of the original leaching process. Alternatively, or additionally, supplemental ammonia may be added to the leachate to provide sufficient ammonia to prevent the formation of CoO.

[0050] If the leachate contains Ni, the presence of ammonia is also beneficial. Ammonia beneficially complexes with Ni, particularly at pH values ​​in the range of 9–10, to form stable, soluble Ni ammonia sulfate. This supports the selective extraction and recovery of Ni, as will be generally discussed below.

[0051] Once Mn is recovered from the leachate, the leachate, which is substantially free of Mn, can then be treated for the recovery of Cu.

[0052] Cu ions can be recovered via a solvent extraction process. Specifically, the leachate is brought into contact with an extractant to recover Cu ions from the leachate and form a Cu-packed extractant. The extractant is then stripped with a stripping agent such as sulfuric acid to recover Cu in the form of CuSO4(aq). If desired, the Cu metal can be recovered via methods known to those skilled in the art, such as electrolytic extraction.

[0053] It is important that the leachate be subjected to an oxidation process before the recovery of Cu. There are two reasons for this. Firstly, the oxidation process facilitates the recovery of Mn. If a significant amount of Mn is present during the solvent extraction of Cu and Ni, Mn can be co-extracted with Cu and Ni and then recovered with Ni, thus contaminating the recovered Ni product and thus causing downstream problems with the purity of the resulting Ni product, as well as requiring an additional, more expensive unit process step to separate Ni and Mn. Therefore, Mn should be recovered before Cu and Ni. The second reason is that if Co is present in the leachate, this will cause problems with the Co 2+ From Co 3+ This is because it is oxidized to Co. This also prevents the recovery of cobalt during solvent extraction, and therefore Co 2+ This prevents contamination of the extractant by ions.

[0054] In embodiments in which the leachate additionally contains Ni ions, Ni can be recovered before, after, or using Cu. However, it is preferable that Cu and Ni ions be recovered together from the leachate in the solvent extraction process. That is, Ni ions can be extracted simultaneously with Cu ions via the solvent extraction process. Once extracted, Ni ions can then be selectively stripped from the extractant using a stripping agent before stripping the Cu ions. The extractant is preferably sulfuric acid, in which case Ni ions can be stripped at a relatively lower terminal sulfuric acid concentration than Cu ions, thus enabling the selective recovery of Ni and Cu ions. If desired, the Cu and Ni metals can each be recovered by methods known to those skilled in the art, such as electrolytic extraction.

[0055] After sequentially removing Mn, followed by the removal of Cu (and Ni, if present) from the leachate, the leachate can then be treated to recover Co, if present. Co can be recovered from the leachate via a precipitate, such as a sulfide. The cobalt sulfide precipitate can be separated from the leachate as a high-purity solid product using standard solid-liquid separation processes, as is known to those skilled in the art.

[0056] The leachate, which is substantially free of Co, Cu, Mn, and Ni, can then be treated to recover ammonia, for example by steam stripping, before recovering Li.

[0057] The inventors have found that Li can be recovered in the form of ammonium lithium sulfate by crystallization, for example, by concentrating the leachate by evaporating water from the leachate to crystallize the ammonium lithium sulfate. The ammonium lithium sulfate can then be recovered by solid-liquid separation (e.g., filtration, centrifugation, etc.) and then thermally decomposed into lithium sulfate crystals, ammonia gas, and sulfur oxide gas. The sulfur oxide gas can be reacted with ammonia gas and water to regenerate ammonium sulfate if desired.

[0058] Therefore, the method provides an effective solution for the recovery of high-purity Mn, Cu, and Li, and optionally, Co and Ni, from leachates containing these metal species.

[0059] The present invention is described below in relation to several embodiments thereof, which are essentially intended to be illustrative and should not be interpreted in an restrictive manner.

[0060] Exemplary Embodiments This embodiment describes a method for recovering metals from a feed containing one or more lithium-ion battery types. In this particular embodiment, the feed contains at least cobalt, lithium, manganese, and nickel copper metals and metal oxides.

[0061] This method includes an initial leaching step in which lithium-ion battery waste (which may be combined with other electronic waste sources) is subjected to alkaline leaching in a first leaching solution containing ammonium sulfate. In this particular embodiment, the first leaching solution additionally contains ammonia found to enhance the leaching process, as previously described. Leaching is carried out at atmospheric pressure and ambient temperature. However, leaching may be carried out at high temperatures, for example, below the boiling point of the leaching solution.

[0062] Alkaline leaching oxidizes the elemental copper contained in the lithium-ion battery to soluble copper ions and reduces or otherwise releases nickel, cobalt, manganese, and lithium ions contained in the battery, for example, nickel-manganese-cobalt (NMC), lithium-cobalt oxide (LCO), and lithium-ion manganese oxide (LMO). Thus, leaching results in the formation of a first leachate containing soluble ions of cobalt, copper, lithium, manganese, and nickel, as well as a first solid residue.

[0063] Next, the first leachate is separated from the first solid residue.

[0064] The first solid residue contains low-value materials such as iron and aluminum, but depending on the type of lithium-ion battery waste, it may also contain residual cobalt, lithium, manganese, and nickel compounds. For example, if the feed contains lithium-ion phosphate (LFP) and lithium nickel cobalt aluminum oxide (NCA) batteries, some of the cobalt, lithium, and nickel will be retained in the first solid residue.

[0065] The amounts of cobalt, lithium, manganese, and nickel may be such that further recovery of these metals is economically viable and therefore desirable. If so, the first solid residue may be subjected to a further leaching step with a second leaching solution containing ammonium sulfate, preferably ammonium chloride. The second leaching is carried out at atmospheric pressure and ambient temperature. However, as mentioned above, the second leaching may be carried out at high temperatures, such as below the boiling point of the leaching solution. The second leaching may be an oxidative leaching; that is, an oxidizing agent such as air, hydrogen peroxide, or hypochlorite may be used during leaching to aid in the recovery of the metals. Generally, in feeds containing NCA and / or NMC battery materials, an oxidizing agent is not required because cobalt, nickel, and manganese are present in sufficient amounts to provide a sufficiently high redox half-cell potential >100mV. However, if the redox half-cell potential is less than 100mV, as is typically the case with LFP battery waste feeds, an oxidizing agent is useful to assist or enhance the leaching process.

[0066] The second leaching provides a second leachate containing soluble ions of cobalt, lithium, manganese, and nickel, as well as a second solid residue.

[0067] Next, the second leachate is separated from the second solid residue. As described above, depending on the type of battery present, the second solid residue may contain commercially recoverable amounts of residual cobalt, lithium, manganese, and nickel.

[0068] To further recover these metals, the second solid residue is subjected to a size separation process to classify the first solid residue into a coarse fraction and a fine fraction. The fine fraction contains more than 80% residual nickel, and also contains some residual cobalt, lithium, and manganese. The fine fraction is subjected to acid leaching, such as sulfuric acid, to provide a third leachate containing cobalt, lithium, manganese, and nickel ions, as well as a third solid residue. The third leaching is carried out at atmospheric pressure and ambient temperature. However, as mentioned above, the third leaching may be carried out at high temperatures, such as below the boiling point of the leaching solution.

[0069] Next, the third leachate is separated from the third solid residue.

[0070] In alternative embodiments, it will be understood that the second and / or third leaching step may be omitted.

[0071] Aluminum, iron, and phosphates are not extracted in significant amounts and are generally retained in the first, second, and / or third solid residues. Given this, the leaching process is selective for expensive metals such as copper, cobalt, lithium, manganese, and nickel.

[0072] The first, second, and third leachates can then be combined to form a combined leachate, which can then be subjected to a number of steps for the selective recovery of cobalt, copper, lithium, manganese, and nickel.

[0073] To recover manganese, the combined leachate is subjected to an oxidation step in the presence of ammonia to precipitate manganese in the form of manganese oxides such as Mn2O3, Mn3O4, and / or MnO2 (not Mn(OH)2). The inventors have found that if the leachate additionally contains cobalt ions, the presence of ammonia causes the cobalt ions to form complexes with the ammonia, making them soluble Co 3+It was found that retaining the manganese oxide in ionic form and preventing the formation of CoO precipitates is important. The manganese oxide precipitate can then be recovered from the combined leachate using any solid-liquid separation process commonly known to those skilled in the art, such as filtration.

[0074] The combined leachate can then be subjected to a solvent extraction step for the extraction of copper and / or nickel. The solvent then packed with copper and / or nickel can be separated from the combined leachate, and the copper and / or nickel can subsequently be recovered from the solvent. Copper and nickel can be recovered from the solvent by stripping with a stripping agent such as sulfuric acid. Generally, nickel can be selectively stripped at a lower residual acid concentration than copper, for example, in a pH range of about 1 to 4, and then copper is stripped by increasing the acid concentration to, for example, above about 50 g / L H2SO4. This two-step stripping makes it possible to selectively separate copper and nickel.

[0075] The combined leachate can then be subjected to further processing to recover the cobalt. In this embodiment, the cobalt is recovered via a cobalt precipitation process, thereby treating the combined leachate with a sulfide such as hydrogen sulfide gas or ammonium sulfide to precipitate cobalt sulfide. The cobalt sulfide can then be recovered from the combined leachate using any solid-liquid separation process commonly known to those skilled in the art, such as filtration.

[0076] The combined leachate, which has been substantially depleted of cobalt, copper, manganese, and nickel, can be further processed to recover ammonia, ammonium salts, and lithium.

[0077] Ammonia is steam-stripped from the leachate, and the recovered ammonia is recycled and reused as a component of the first leachate solution. The lithium in the leachate is generally in the form of lithium sulfate. This lithium sulfate can be crystallized with ammonium sulfate (e.g., via an evaporation process) in the form of lithium ammonium sulfate and separated from the leachate. The lithium ammonium sulfate can then be subjected to heat treatment to decompose it into lithium sulfate solid, ammonia gas, and sulfur oxide gas. The ammonia and sulfur oxide gas can be captured and reacted with water, such as in a wet scrubber, to form ammonium sulfate, which can then be recycled to the first and / or second leachate step.

[0078] The process will be described in more detail with reference to Figure 1. Figure 1 is a process flow diagram illustrating the method of the present invention, generally according to the embodiments described above.

[0079] The method in Figure 1 describes the recovery of nickel product 27, copper product 32, cobalt product 37, and lithium product 48. In this embodiment, feed stream 1 is subjected to a pretreatment process, e.g., crushing 100 to less than 5 mm, e.g., less than 1 mm, to make feed stream 1 suitable for further processing. The resulting crushed feed stream 2 is then passed through an alkaline leaching circuit 110 and brought into contact with a liquid containing ammonia, ammonium sulfate with / without ammonium chloride 39, and ammonia supplements 3 and 40 to solubilize the metal species. The conditions in the alkaline leaching circuit 110 are approximately 5-10% solid, approximately 50°C, atmospheric pressure, residence time of approximately 12 hours, pH of approximately 9, approximately 200 g / L of ammonium sulfate in the presence of ammonia, and approximately 20 g / L of ammonium chloride, if present.

[0080] The resulting alkaline leaching slurry 4 is subjected to a solid-liquid separation step 120, such as a concentration tank or multiple concentration tanks with washing, and the ammonia leachate 6 is directed to a manganese oxide precipitation circuit 180.

[0081] The underflow 5 of the concentration tank is directed to the ammonium sulfate leaching circuit 130 and brought into contact with a solution containing ammonium sulfate 47 and ammonium sulfate supplement 7. The conditions of the ammonium sulfate leaching circuit 130 are approximately 5-10% solid, approximately 90-100°C, atmospheric pressure, residence time of approximately 4-12 hours, and containing approximately 200 g / L of ammonium sulfate and 20 g / L of ammonium chloride.

[0082] The ammonium sulfate leachate 8 is directed to a screen 140, for example, 75-500 μm, for example, about 180 μm, to separate the coarse and fine fractions of the particles. The coarse fraction 9 is stored, and the fine fraction 10 is directed to a concentrator 150. The concentrator overflow, for example, the ammonium sulfate leachate 11, is directed to a manganese oxide precipitation circuit 180.

[0083] The underflow 12 of the concentrator is directed to an acid leaching circuit 160, where it comes into contact with sulfuric acid 13. The conditions for the acid leaching circuit 160 included a temperature in the range of about 20 to 100°C, for example, 70°C; a pH less than about 3.5, for example, about 2.5; a residence time of about 4 to 12 hours; and the addition of 30% solid and 98% sulfuric acid.

[0084] The acid leachate 14 is subjected to filtration 170, and the solid is washed to produce leachate residue 15 for storage and acid leachate 17 directed to the manganese oxide precipitation circuit 180.

[0085] The leachates 6, 11, and 17 are directed to a manganese oxide precipitation circuit 180, where air 18 is sparged into the liquid to force the precipitation of manganese oxide. The precipitated slurry 19 is subjected to solid-liquid separation by concentration and filtration 190. The manganese product 20 is washed and stored.

[0086] The metal-containing leachate 21 after manganese precipitation is directed to a copper and nickel solvent extraction circuit 200 and contacted with a commercially available oxime extractant, such as LIX84I™ (an extractant containing the active ingredient 2-hydroxy-5-nonylacetophenone oxime). Copper and nickel are packed into the copper extractant, and the packed extractant 23 is separated from the raffinate 22. The packed extractant 23 is contacted with dilute sulfuric acid 24, for example 150 g / L sulfuric acid, in the nickel stripping stage 210 to produce a packed strip containing nickel 25 and nickel depletion extractant 28. The nickel depletion extractant 28 is contacted with dilute sulfuric acid solution 29, for example 200 g / L sulfuric acid, in the copper stripping stage 220 to produce a packed strip containing copper 30. The stripped organic matter (not shown) is recycled back into the extraction circuit 200 (not shown) to extract more copper and nickel. The nickel product 27 (appearing as nickel sulfate on the surface) is recovered from the nickel-filled strip solution 25 during the nickel crystallization step 230. The copper product 32 (appearing as copper sulfate on the surface) is recovered from the copper-filled strip solution 30 during the copper electrolytic extraction step 240.

[0087] The copper and nickel-depleted raffinate 22 is directed to the cobalt recovery circuit 250, where a precipitation reagent, such as hydrogen sulfide gas 33, is added to force the precipitation of cobalt sulfide. The resulting slurry 34 is subjected to solid-liquid separation by, for example, a concentrator and filter 260, and washed with water 35 to produce a cobalt product 37.

[0088] The majority of the resulting filtrate 39, which contains ammonia and ammonium sulfate, is directed to the ammonia leaching circuit 110 to recover more metal. The remaining filtrate 38 is directed to the ammonia recovery circuit 270, where vapor 41 is used to strip the ammonia 40. The recovered ammonia 40 is reused in the process, specifically, for example, in the ammonia leaching 110.

[0089] The ammonia-free liquid 42 is directed to an ammonium sulfate leaching 130 and also to a crystallizer 280 where condensate 43 is removed by forced evaporation and lithium ammonium sulfate 46 is crystallized. The crystallizer discharge is subjected to solid-liquid separation using a centrifuge 290, and the centrate 45 is directed to the ammonium sulfate leaching 130. The lithium ammonium sulfate 46 intermediate is subjected to calcination in a kiln 300, and the solid lithium sulfate 48 is collected for sale. The exhaust gas 47 is collected in a wet scrubber using scrubbing water 49 to recover the ammonium sulfate solution 50.

[0090] Example 1 A total of 224 kg of battery fragments, consisting of a mixture of LFP (50%), NMC622 (20.5%), NMC811 (11%), NCA (11%), and LCO (7.7%), was processed through a pilot plant. The weighted average feed grade was 11.9% Cu, 6.45% Ni, 3.09% Co, 1.81% Li, and 1.51% Mn. The pilot plant consisted of primary leaching in ammonia, ammonium sulfate, and ammonium chloride solutions at 50°C and pH 9.0, secondary leaching in ammonium sulfate and ammonium chloride solutions at 90°C, pH 5-6, and Eh > 120 mV, and tertiary leaching in sulfuric acid at pH 3.0-3.5 and 90°C. Through a three-stage leaching process, the extraction rates for nickel, cobalt, copper, lithium, and manganese were 96.7%, 98.4%, 97.6%, 97.7%, and 97.5%, respectively.

[0091] The leachate was bound and aeration was performed with a target Eh > 100 mV, and the pH was controlled with ammonia to a target pH of 10.0. The manganese concentration in the solution after oxidation was an average of 10 mg / L of Mn. This corresponds to a manganese recovery rate of 98.4%. The manganese product contained 39% Mn.

[0092] The manganese-removed solution was treated through a solvent extraction plant using LIX84I as the extractant. Copper and nickel extraction achieved average selectivity of 99.8% and 99.6% in the test run. Excellent selectivity was achieved in the circuit. The average values ​​for the nickel-packed strip solution were 73.1 g / L Ni and 52 mg / L Cu, and the average values ​​for the copper-packed strip solution were 60.8 g / L Cu and 2.0 g / L Ni.

[0093] Copper was successfully electrolytically extracted from copper-filled strips, and the product contained >99.9% Cu.

[0094] Solvent-extracted raffinates were treated through a cobalt recovery circuit in which hydrogen sulfide gas was spurged into the liquid. An average cobalt recovery rate of 98.5% was achieved in the cobalt recovery circuit. The cobalt product contained 27% Co.

[0095] Lithium recovery involved forced crystallization of the cobalt precipitate filtrate. An intermediate containing 1.1% Li was recovered. This material was batch calcined to produce a lithium sulfate product containing 10% Li, mainly present as lithium sulfate.

[0096] It will be understood that the present invention, as disclosed and defined herein, extends to all alternative combinations of two or more individual features referred to or revealed herein or in the drawings. All of these different combinations constitute various alternative embodiments of the present invention.

Claims

1. A method for recovering metals from an alkaline leaching leachate of electronic waste, wherein the leaching leachate contains Cu, Li, and Mn ions, and the method is To recover Mn from the aforementioned leachate, After the step of recovering Mn from the leachate, Cu is recovered from the leachate. A method comprising recovering Li from the leachate after the step of recovering Cu from the leachate.

2. The method according to claim 1, wherein the leachate further contains Co ions, and the method further comprises recovering Co from the leachate after the step of recovering Cu from the leachate and before the step of recovering Li from the leachate.

3. A method for recovering metals from an alkaline leaching leachate of electronic waste, wherein the leaching leachate contains Cu, Li, Ni, and Mn ions, and the method is To recover Mn from the aforementioned leachate, After the step of recovering Mn from the leachate, Cu and Ni are recovered from the leachate. A method comprising recovering Li from the leachate after the step of recovering Cu and Ni from the leachate.

4. The method according to claim 2, wherein the leachate further contains Co ions, and the method further comprises recovering Co from the leachate after the step of recovering Cu and Ni from the leachate and before the step of recovering Li from the leachate.

5. The step of recovering Mn from the leachate is, The aforementioned leachate is treated with an oxidizing agent to form a Mn precipitate, The method according to any one of the prior claims, comprising separating the Mn precipitate from the leachate.

6. The method according to claim 5, wherein the oxidizing agent is selected from the group consisting of air, hydrogen peroxide, and / or hypochlorite.

7. The aforementioned Mn precipitate is Mn ２ O ３ Mn ３ O ４ and / or MnO ２ The method according to claim 5 or 6, wherein the manganese oxide is selected from the group consisting of the following.

8. The step of recovering Li from the leachate is, Crystallizing ammonium lithium sulfate from the aforementioned leachate, A method according to any one of the prior claims, comprising separating crystalline lithium ammonium sulfate from the leachate.

9. The method according to claim 8, further comprising thermally decomposing the crystalline ammonium lithium sulfate to form a gas containing ammonia, sulfur oxides, and solid lithium sulfate.

10. The step of recovering Cu ions from the leachate uses a solvent extraction process, and the solvent extraction process is The leachate is brought into contact with an extractant to adsorb Cu ions onto the extractant, thereby forming a Cu-filled extractant. A method according to any one of the prior claims, comprising separating the Cu-filled extractant from the leachate.

11. The method according to claim 10, further comprising stripping the Cu ions from the Cu-filled extractant.

12. The step of recovering Cu and Ni ions from the leachate includes recovering Cu and Ni ions simultaneously in a solvent extraction process, and the solvent extraction process is The leachate is brought into contact with an extractant to adsorb Cu and Ni ions onto the extractant, thereby forming a Cu, Ni packed extractant. The method according to claim 2 or 4, comprising separating the Cu, Ni-packed extractant from the leachate.

13. The method according to claim 12, further comprising using a stripping agent to strip the Cu and Ni ions from the Cu, Ni packed extractant, wherein the Ni ions are selectively recovered at a first stripping agent concentration, and the Cu ions are subsequently recovered at a second stripping agent concentration, the first stripping agent concentration being less than the second stripping agent concentration.

14. Prior to the step of recovering Cu, the method treats the leachate with an oxidizing agent to convert Co ions into Co ２＋ From Co ３＋ The method according to claim 3, further comprising oxidation.

15. Before the step of recovering Cu and Ni, the method further comprises treating the leachate with an oxidizing agent to oxidize Co ions from Co ２＋ to Co ３＋ The method according to claim 4, wherein

16. The step of recovering Co from the leachate is, The aforementioned leachate is treated with a precipitate to form a Co precipitate, The method according to any one of claims 2, 4, 14, or 15, comprising separating the Co precipitate from the leachate.

17. The method according to any one of the prior claims, wherein the leachate comprises ammonium sulfate and ammonia.

18. The leachate has an initial pH in the range of approximately 8.5 to 10.5, and / or The method according to any one of the prior claims, wherein during one or more of the recovery steps, or between each of them, the leachate has a pH in the range of about 8.5 to 10.

5.

19. The method according to any one of the prior claims, wherein the leaching solution comprises ammonia and ammonium sulfate in a ratio of about 1:2 to about 1:

20.

20. The leachate has a Cu:Mn ratio of approximately 0.5:1 to approximately 2:1, or The leachate has a Cu:(Mn+Co) ratio of approximately 0.5:1 to approximately 2:1, or The leachate has a Cu:(Mn+Ni) ratio of approximately 0.5:1 to approximately 2:1, or The method according to any one of the prior claims, wherein the leachate has a Cu:(Mn+Co+Ni) ratio of about 0.5:1 to about 2:1.

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