Methods for Treating Sulfides

Abstract

To provide a processing method of a sulfide suitable for obtaining nickel and / or cobalt from a sulfide containing copper and nickel and / or cobalt.SOLUTION: A method of processing a sulfide containing copper, nickel and / or cobalt comprises: a step of pulverizing sulfide to obtain pulverized sulfide with a particle size of 800 mμ or smaller; and a leaching step of applying a leaching treatment with an acid under coexistence of the sulfide to the pulverized sulfide to obtain a leaching liquid. For example, the sulfide to be treated are produced by the addition of the sulfide to a melt obtained by reductive heating and melting of waste lithium ion batteries.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for treating sulfides containing nickel and / or cobalt and copper. [Background technology]

[0002] Vehicles such as electric vehicles and hybrid vehicles, as well as electronic devices such as mobile phones, smartphones, and personal computers, are equipped with lithium-ion batteries (hereinafter also referred to as "LIBs"), which are characterized by their light weight and high output.

[0003] LIBs are made by placing a negative electrode material, which uses copper foil as a negative electrode current collector with graphite or other negative electrode active material fixed to its surface, and a positive electrode material, which uses aluminum foil as a positive electrode current collector with lithium nickel oxide or lithium cobalt oxide fixed to a positive electrode current collector, together with a separator made of a porous resin film such as polypropylene, inside an exterior can made of metal such as aluminum or iron, or plastic such as polyvinyl chloride, and then sealing the negative electrode material with lithium hexafluorophosphate (LiPF 6 The structure is impregnated with an organic solvent containing an electrolyte such as .

[0004] Once LIBs are incorporated into the vehicles and electronic devices mentioned above, they will eventually become unusable due to deterioration of the vehicles and electronic devices or the lifespan of the LIB, and become waste lithium-ion batteries (waste LIBs). Waste LIBs also include those that are generated as defective products during the manufacturing process. These waste LIBs contain valuable components such as nickel, cobalt, and copper, and it is desirable to recover and reuse these valuable components in order to make effective use of resources.

[0005] Generally, when trying to efficiently recover valuable components from metal equipment, components, or materials, it is thought that the easiest method is dry processing using pyrometallurgical technology, in which the materials are put into a furnace, melted at high temperatures, and separated into valuable metals and slag that can be disposed of.

[0006] For example, Patent Document 1 discloses a method for recovering valuable metals using a dry process. By applying the method disclosed in Patent Document 1 to recover valuable metals from waste LIBs, a copper alloy containing nickel and the like can be obtained. Although the method using a dry process has the problem of requiring energy for heating to high temperatures, it has the advantage of being able to process various impurities in a simple process and separate them all at once. In addition, the obtained slag has relatively stable chemical properties, so there is no concern about causing environmental problems, and it also has the advantage of being easy to dispose of.

[0007] However, when waste LIBs are treated using dry processing, some valuable components, especially most of the cobalt, are distributed in the slag, resulting in unavoidable losses. In addition, since the metal obtained by dry processing is an alloy containing valuable components, in order to reuse it, a purification process is required to separate the components from the alloy and remove impurities.

[0008] A commonly used refining method in the dry process is to separate, for example, copper from lead or lead from zinc by slowly cooling from a high-temperature molten state. However, when the main components are copper and nickel, such as in waste LIBs, the copper and nickel melt uniformly throughout the entire composition range, so even if they are slowly cooled, the copper and nickel simply mix and solidify in layers, and they cannot be effectively separated.

[0009] In addition, there is a refining method in which nickel is disproportionated using carbon monoxide (CO) gas to volatilize it from copper and cobalt and separate it. However, the use of highly toxic CO gas makes it difficult to ensure safety.

[0010] Also, as a method for separating copper and nickel that has been carried out industrially, there is a method for roughly separating mixed matte (sulfide). In this method, matte containing copper and nickel is produced in a smelting process, and this is slowly cooled in the same manner as in the above-mentioned case, so that it is separated into sulfides containing a lot of copper and sulfides containing a lot of nickel. However, even with this method, the separation of copper and nickel is only at a rough level, so in order to obtain nickel and copper with high purity, a separate process such as electrolytic refining is required.

[0011] As another method, a method using the vapor pressure difference via chloride has been considered, but since this process involves handling a large amount of toxic chlorine, it is difficult to say that this method is industrially suitable due to the need to take measures against corrosion of the equipment and safety measures.

[0012] The same is true for the separation of copper and cobalt, and cobalt and nickel.

[0013] Thus, compared with wet methods, the separation and purification of each element by dry methods is limited to a crude separation level or has the drawback of being high cost and therefore less practical.

[0014] On the other hand, hydrometallurgy, which uses acid, neutralization, solvent extraction, and other processes, has the advantage of consuming less energy and being able to separate the mixed valuable components individually and directly recover them with high purity. However, when hydrometallurgy is used to treat waste LIBs, the hexafluorophosphate anion, an electrolyte component contained in waste LIBs, is difficult to treat and cannot be completely decomposed even with high-temperature, high-concentration sulfuric acid, and is mixed into the acid solution from which the valuable components are leached. Furthermore, since the hexafluorophosphate anion is a water-soluble carbonate ester, it is difficult to recover phosphorus and fluorine from the aqueous solution after recovering the valuable components, so various measures must be taken to prevent its release into public sea areas, etc.

[0015] In addition, it is not easy to obtain a solution that can be used to efficiently leach only valuable components from waste LIBs using only acid and to be used for purification. In other words, waste LIBs themselves are difficult to leach, and it is not easy to leach valuable components at a sufficient leaching rate. Furthermore, if waste LIBs are forcibly leached using a highly oxidizing acid, large amounts of components that are not the target of recovery, such as aluminum, iron, and manganese, are leached out along with the valuable components, which creates problems such as an increase in the amount of neutralizing agent added to neutralize these components and an increase in the amount of wastewater to be handled.

[0016] Furthermore, when the pH of the acidic leachate is adjusted or impurities are neutralized and fixed into a precipitate in order to subject the acidic leachate to a separation means such as solvent extraction or ion exchange, the amount of precipitate generated by the neutralization increases, which poses many problems in terms of securing a treatment site, ensuring stability, etc.

[0017] In addition, waste LIBs may still have residual electric charges, and directly crushing or cutting the waste LIB itself or otherwise mechanically processing it may cause the positive and negative electrodes to come into direct contact within the waste LIB, resulting in a sudden flow of excessive current, which may lead to heat generation or explosion, etc. For this reason, it becomes necessary to carry out time-consuming processing such as immersing the waste LIB in a highly conductive solution such as saline solution, connecting the positive and negative electrodes via a certain resistance, and discharging the waste LIB.

[0018] Thus, processing waste LIBs using only wet processing is not necessarily an advantageous method.

[0019] Therefore, attempts have been made to combine dry and wet processes for waste LIBs that are difficult to process using the above-mentioned dry or wet processes alone, in other words, to remove impurities as much as possible through dry processes such as roasting the waste LIBs to produce a homogeneous waste LIB processed product, and then to wet process the resulting processed product to separate it into valuable components and other components.

[0020] In this method that combines dry and wet processing, the fluorine and phosphorus in the electrolyte are removed by volatilization in the dry processing, and the organic components of the waste LIBs, such as plastics and separators, which are structural components of the waste LIBs, are also decomposed by heat. In addition, the waste LIBs processed material obtained by the dry processing has uniform properties, so it is easy to handle as a uniform raw material in the wet processing.

[0021] However, simply combining dry and wet processing still leaves the problem of recovery loss, as mentioned above, due to the cobalt contained in waste LIBs being distributed into the slag.

[0022] In this regard, a method of reducing and melting cobalt has been considered, in which the atmosphere, temperature, degree of reduction, etc. in the dry treatment are adjusted to distribute cobalt as metal and reduce its distribution to the slag. However, the metal obtained by such a method is a poorly soluble corrosion-resistant alloy based on copper and containing nickel and cobalt. Even if valuable components are separated and recovered from the corrosion-resistant alloy, they cannot be effectively recovered because they are difficult to dissolve in acid.

[0023] In addition, when a corrosion-resistant alloy is dissolved in acid, for example, using chlorine gas, the resulting solution (leachate) contains high concentrations of copper and relatively low concentrations of nickel and cobalt. Although nickel and cobalt can be easily separated using known methods such as solvent extraction, it is difficult to separate a large amount of copper from nickel and cobalt easily and at low cost.

[0024] As described above, it has been difficult to efficiently separate only nickel and / or cobalt from waste LIBs, which contain various components in addition to the valuable components copper, nickel, and cobalt. In particular, it has been difficult to separate only nickel and / or cobalt by wet processing from sulfides containing copper and nickel and / or cobalt, which are produced by sulfurizing the molten material obtained by reducing and heating the waste LIBs in dry processing and adding a sulfurizing agent such as elemental sulfur (solid sulfur).

[0025] The above-mentioned problems also exist when copper, nickel, and cobalt are separated from waste batteries containing copper, nickel, and cobalt other than waste LIBs, and also exist when copper, nickel, and cobalt are separated from alloys containing copper, nickel, and cobalt derived from sources other than waste batteries. [Prior art documents] [Patent documents]

[0026] [Patent Document 1] JP 2012-172169 A [Patent Document 2] Japanese Patent Application Publication No. 63-259033 Summary of the Invention [Problem to be solved by the invention]

[0027] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a sulfide processing method capable of selectively separating nickel and / or cobalt from sulfides containing copper and nickel and / or cobalt obtained, for example, by subjecting waste LIBs to dry processing. [Means for solving the problem]

[0028] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by pulverizing a sulfide containing copper and nickel and / or cobalt (sulfide to be treated) to a particle size of a predetermined size or less, and subjecting the pulverized sulfide to an acid leaching treatment in the presence of a sulfiding agent, thereby completing the present invention.

[0029] (1) The first aspect of the present invention is a method for treating sulfides containing copper and nickel and / or cobalt, The method for treating sulfides includes a crushing step of crushing the sulfide to obtain crushed sulfide having a particle size of 800 μm or less, and a leaching step of leaching the crushed sulfide with an acid in the presence of a sulfiding agent to obtain a leachate.

[0030] (2) A second aspect of the present invention is a method for treating a sulfide according to the first aspect of the present invention, wherein in the leaching step, a leaching solution is obtained by carrying out a leaching treatment with at least one acid selected from sulfuric acid, hydrochloric acid, and nitric acid.

[0031] (3) A third aspect of the present invention is the method for treating sulfides according to the first or second aspect of the present invention, further comprising a reduction step of subjecting the leachate to a reduction treatment using a metal that is less noble than copper.

[0032] (4) A fourth aspect of the present invention is the method for treating sulfides according to the third aspect of the present invention, further comprising an oxidation / neutralization step of obtaining a solution containing nickel and / or cobalt by adding an oxidizing agent and a neutralizing agent to the solution obtained in the reduction step.

[0033] (5) A fifth aspect of the present invention is the method for treating sulfides according to the fourth aspect of the present invention, wherein the oxidizing agent is at least one selected from hydrogen peroxide and hypochlorous acid.

[0034] (6) A sixth aspect of the present invention is the method for treating sulfides according to the fourth or fifth aspect of the present invention, wherein the neutralizing agent is at least one selected from sodium hydroxide and potassium hydroxide.

[0035] (7) The seventh aspect of the present invention is a method for treating sulfides according to any one of the first to sixth aspects of the present invention, wherein the sulfides are produced by adding a sulfiding agent to a melt obtained by reducing and heating waste lithium-ion batteries to sulfurize the melt.

[0036] (8) The eighth aspect of the present invention is a method for recovering valuable metals from used lithium-ion batteries, comprising a step of obtaining a leachate by leaching with an acid a sulfide containing copper and nickel and / or cobalt, the sulfide being produced by sulfurizing a molten material obtained by reducing and heating the used lithium-ion batteries, in which the sulfide is subjected to a pulverization treatment to obtain pulverized sulfide having a particle size of 800 μm or less, and the pulverized sulfide is subjected to an acid leaching treatment in the presence of a sulfurizing agent.

[0037] (9) The ninth aspect of the present invention is a method for recovering valuable metals from used lithium-ion batteries, comprising: a dry treatment step of sulfurizing a melt obtained by reducing and heating the used lithium-ion batteries to obtain a sulfide containing copper and nickel and / or cobalt; and a wet treatment step of subjecting the sulfide to a leaching treatment with acid, in which the sulfide is pulverized to obtain pulverized sulfide having a particle size of 800 μm or less by pulverizing the sulfide, and the pulverized sulfide is subjected to a leaching treatment with acid in the presence of a sulfurizing agent. Effect of the Invention

[0038] According to the present invention, nickel and cobalt can be efficiently and selectively separated from sulfides containing copper and nickel and / or cobalt. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] A specific embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described in detail below. Note that the present invention is not limited to the following embodiment, and can be practiced with appropriate modifications within the scope of the object of the present invention. Note that in this specification, the expression "X to Y" (X and Y are arbitrary numerical values) means "X or more and Y or less."

[0040] ≪1. Overview≫ The sulfide treatment method of the present invention is a method for treating a sulfide containing copper and nickel and / or cobalt, and is a method for selectively separating nickel and / or cobalt from the sulfide. The sulfide to be treated is, for example, a sulfide containing copper and nickel and / or cobalt that is produced by a dry process in which a waste lithium ion battery (waste LIB) is reduced and heated to melt, and a sulfurizing agent such as elemental sulfur is added to the resulting melt to perform sulfurization.

[0041] Specifically, the sulfide processing method of the present invention is characterized by including a grinding step in which a sulfide is subjected to a grinding treatment to obtain ground sulfide having a particle size of 800 μm or less, and a leaching step in which the obtained ground sulfide is subjected to an acid leaching treatment in the presence of a sulfurizing agent to obtain a leachate.

[0042] In this way, as a method for treating sulfides containing copper and nickel and / or cobalt, the particle size of the sulfides is reduced to 800 μm or less, and the crushed sulfides are subjected to an acid leaching treatment in the presence of a sulfiding agent. This makes it possible to leach nickel and cobalt at a good leaching rate, and for copper, copper can be precipitated as copper sulfide, so that nickel and cobalt can be leached extremely selectively into the leachate and effectively separated from copper.

[0043] Here, as described above, examples of sulfides to be treated include sulfides produced by dry processing in which waste lithium-ion batteries (waste LIBs) are reduced and heated to melt, and a sulfurizing agent such as elemental sulfur is added to the resulting melt to perform sulfurization. In addition, the sulfide may be produced by dry processing of waste batteries containing copper and nickel and / or cobalt other than lithium-ion batteries. In addition, the sulfide may be produced by dry processing of materials containing copper and nickel and / or cobalt, without being limited to batteries. Note that waste batteries including waste LIBs include waste batteries due to deterioration of automobiles or electronic devices, scrap batteries generated as the battery life expires, waste batteries such as defective products during the battery manufacturing process, used batteries, or batteries discarded as defective products during battery manufacturing.

[0044] 2. Method of treating sulfides Below, as a specific embodiment of the present invention (hereinafter referred to as "this embodiment"), a more specific explanation will be given by taking as an example a case in which the processing target is a sulfide containing copper and nickel and / or cobalt, which is obtained by dry processing of waste LIBs.

[0045] The sulfide treatment method according to the present embodiment includes a crushing step S1 in which sulfide is crushed to obtain crushed sulfide, and a leaching step S2 in which the crushed sulfide is leached with an acid. It can further include a reduction step S3 in which the resulting leachate is reduced, and an oxidation / neutralization step S4 in which an oxidizing agent and a neutralizing agent are added to the resulting solution (reduced solution) to perform an oxidation / neutralization treatment.

[0046] Here, the sulfide to be treated is a sulfide obtained by subjecting waste LIBs to dry treatment. Specifically, the sulfide contains copper and nickel and / or cobalt and is obtained by reducing and heating the waste LIBs to melt, and then adding a sulfurizing agent such as elemental sulfur to the resulting molten material to sulfurize it.

[0047] Specifically, in the above-mentioned dry treatment, the waste LIBs are first placed in a roasting furnace and subjected to an oxidative roasting process at a temperature of about 300°C to 1000°C, and then the obtained roasted product (post-roasted product) is placed in a melting furnace such as a graphite crucible or a magnesium crucible and melted under high-temperature conditions of about 1100°C to 1400°C, performing a reducing heat treatment.

[0048] Next, a sulfurization treatment is performed by adding a liquid or gaseous sulfurizing agent such as elemental sulfur (solid sulfur), sodium hydrogen sulfide, sodium sulfide, or hydrogen sulfide gas to the molten material obtained by reduction heating and melting. This makes it possible to obtain sulfides containing copper and nickel and / or cobalt, which are metal components that constitute the waste LIB. In this specification, even if most of the copper is in the form of sulfides and nickel, cobalt, and some unsulfurized copper coexist in a form containing metal or oxygen, etc., they are all referred to as "sulfides".

[0049] [Crushing process] In the pulverization step S1, the sulfide containing copper and nickel and / or cobalt is pulverized to a predetermined particle size or less to obtain pulverized sulfide. Specifically, the sulfide is pulverized to a particle size of 800 μm or less.

[0050] By pulverizing the sulfide in this manner to obtain pulverized sulfide having a particle size of 800 μm or less, when the pulverized sulfide is subjected to treatment in the next leaching step S2, the leaching rate can be increased, and the leaching efficiency of nickel and cobalt can be improved. As will be described in detail later, in the leaching treatment in the leaching step S2, acid leaching is performed in the presence of a sulfiding agent, so that copper can be efficiently fixed in the sulfide as copper sulfide, and nickel and / or cobalt can be selectively leached and separated in the resulting leachate.

[0051] Regarding the particle size of the sulfide, it is preferable to crush it to 700 μm or less, and more preferably to crush it to 500 μm or less. The lower limit of the particle size is not particularly limited, but if the particle size is too small, it becomes difficult to handle and hydrogen sulfide gas may be generated during the leaching treatment, which is not preferable. From this viewpoint, it is preferable to set the lower limit of the particle size to 100 μm or more.

[0052] The method for the pulverization process (pulverization method) is not particularly limited as long as the sulfide can be pulverized to a particle size of 800 μm or less. For example, the sulfide can be pulverized by a method using a known pulverizing device such as a jaw crusher or a vibration mill. The particle size of the pulverized sulfide can be measured, for example, by a laser diffraction scattering method.

[0053] [Leaching process] In the leaching step S2, the crushed sulfide is subjected to an acid leaching treatment to obtain a leachate. At this time, the leaching treatment is performed under conditions in which a sulfurizing agent coexists. According to this method, nickel and / or cobalt contained in the crushed sulfide are leached to obtain a leachate.

[0054] As described above, in the sulfide treatment method according to the present embodiment, pulverized sulfides having a size of 800 μm or less are used as the target of the leaching treatment. Since the majority of copper is contained in the form of sulfide, the leaching rate can be increased compared to, for example, a copper-based corrosion-resistant alloy. In addition, by subjecting pulverized sulfide prepared to a particle size of 800 μm or less to the leaching treatment, the leaching rate by acid can be increased, and the leaching rate can be improved.

[0055] However, the inventors' research has revealed that while the leaching rate can be increased, unsulfurized copper contained in the pulverized sulfide is also leached together with nickel and / or cobalt, and the separability from copper decreases even if the leaching rate is increased. Note that the leached copper can be reduced and separated in the reduction step S3 described below, but if the copper concentration in the leachate is too high, the reduction treatment takes time and a large amount of reducing agent is used to reduce a large amount of copper, so from the viewpoint of productivity, it is preferable to separate as much copper as possible at the stage of the leachate.

[0056] Therefore, in the sulfide treatment method according to the present embodiment, the sulfide is treated by contacting with an acid in the presence of a sulfurizing agent in the leaching treatment, so that the copper contained in the pulverized sulfide is sulfurized by the sulfurizing agent and precipitated as copper sulfide, and the copper sulfide contained in the pulverized sulfide is precipitated as solid copper sulfide in the leaching solution. In this way, both the copper sulfide and the unsulfurized copper contained in the pulverized sulfide are effectively precipitated or precipitated as copper sulfide, and only the nickel and cobalt contained in the pulverized sulfide can be selectively leached into the leaching solution, which not only improves the leaching rate but also makes it possible to very effectively separate copper from nickel and cobalt.

[0057] As the acid, sulfuric acid, hydrochloric acid, nitric acid, etc. can be used, and these acids can be used alone or in combination. Also, sulfuric acid containing chlorides can be used as the acid. Among them, it is preferable to use sulfuric acid. From the viewpoint of realizing the so-called "battery to battery" circulation method, which is an ideal circulation method in which waste LIBs are recycled and used again as LIB raw materials, by using sulfuric acid as the acid, it is possible to obtain a leachate in the form of sulfates that are easy to use as positive electrode materials for lithium-ion batteries.

[0058] The amount of acid used is 1 equivalent or more, preferably 1.2 equivalents or more, more preferably 1.2 equivalents or more and 11 equivalents or less, based on the total amount of nickel and / or cobalt contained in the ground sulfide. By increasing the acid concentration, the reaction rate can be increased.

[0059] The sulfurizing agent used in the leaching treatment may be sodium hydrosulfide or elemental sulfur. When elemental sulfur is used, it is preferable to grind the sulfur appropriately so that the reaction can proceed easily.

[0060] The amount of the sulfurizing agent used is preferably 1 equivalent or more relative to the amount of copper contained in the pulverized sulfide.

[0061] It is preferable to determine appropriate ranges for the temperature and time in the leaching treatment, and the concentration of the slurry obtained by adding an acid and a sulfiding agent to the pulverized sulfide, by conducting preliminary tests in advance.

[0062] In particular, in the leaching treatment, it is preferable to measure the oxidation-reduction potential (ORP) and pH of the leaching solution and control them within a predetermined range. Specifically, it is preferable to control the ORP to be between −200 mV and 300 mV based on a silver / silver chloride electrode. It is also preferable to control the pH to be between 0.5 and 1.6. By keeping the pH in such a range, leaching is promoted and re-dissolution of the precipitated or deposited copper sulfide due to excessive oxidation can be suppressed.

[0063] The end point of the leaching reaction can be determined by measuring the oxidation-reduction potential (ORP) of the leaching solution.

[0064] [Reduction process] In the reduction step S3, the leachate obtained in the leaching step S2 is subjected to a reduction treatment using a reducing agent to obtain a reduced solution containing nickel and / or cobalt. Here, in the treatment in the above-mentioned leaching step S2, copper contained in the crushed sulfide is leached with acid together with nickel and / or cobalt and dissolved in the solution, and a part of it may remain in the solution without reacting with the sulfurizing agent. Therefore, in the reduction step S3, a trace amount of copper remaining in the leachate is reduced to generate a precipitate containing copper, and the generated precipitate is separated by solid-liquid separation to obtain a reduced solution containing nickel and / or cobalt.

[0065] As the reducing agent, for example, a metal baser than copper can be used. Copper in the leachate can be reduced by contacting a metal baser than copper with the leachate. As the metal baser than copper, a metal containing nickel and / or cobalt is preferably used. The sulfide treatment method according to the present embodiment selectively recovers nickel and / or cobalt in the leachate, and by using a metal containing nickel and / or cobalt, which is the recovery target in the reduction treatment, as a reducing agent, there is no need to recover a reducing agent separately in a later step, which is industrially advantageous.

[0066] In addition to the above-mentioned metals, sulfides can also be used as the reducing agent. The sulfide may be solid, liquid, or gaseous. Also, it may be a mixture of the above-mentioned metals and sulfur.

[0067] It is preferable to select the optimum range of the amount of reducing agent to be added and the reaction temperature by conducting tests in advance. In the reduction treatment, it is preferable to monitor the oxidation-reduction potential (ORP) and pH and control them within a predetermined range, and it is preferable to select the optimum range by conducting tests in advance.

[0068] [Oxidation neutralization process] In the oxidation / neutralization step S4, an oxidizing agent and a neutralizing agent are added to the reduced solution obtained in the reduction step S3 to perform oxidation / neutralization treatment, thereby obtaining a solution (neutralized solution) containing nickel and / or cobalt. Specifically, in the oxidation / neutralization step S4, an oxidizing agent is added to the reduced solution to cause an oxidation reaction, and a neutralizing agent is added to control the pH of the solution within a predetermined range, thereby generating a precipitate of iron and / or phosphorus derived from the waste LIBs.

[0069] Although this is not an essential aspect in the treatment of the sulfiding agent, by providing the oxidation neutralization step S4 in this manner, it is possible to separate at least iron and / or phosphorus, which are impurity components, as precipitates, and obtain a solution (neutralized solution) containing purified nickel and / or cobalt.

[0070] As the oxidizing agent, it is preferable to use an oxidizing agent such as hydrogen peroxide or hypochlorous acid.

[0071] The addition of the oxidizing agent is preferably controlled within a predetermined range by monitoring the oxidation-reduction potential (ORP) of the solution. Specifically, the oxidizing agent is added to the solution to control the ORP (with silver / silver chloride as the reference electrode) within a range of 380 mV to 430 mV, for example.

[0072] After the oxidizing agent is added to cause an oxidation reaction, a neutralizing agent is added to control the pH of the solution to preferably within a range of 3.8 to 4.5. By controlling the pH within such a range and carrying out the neutralization treatment, impurities such as at least iron and / or phosphorus can be effectively precipitated.

[0073] The neutralizing agent is not particularly limited, but it is preferable to use an alkali such as sodium hydroxide or potassium hydroxide.

[0074] In the oxidation neutralization treatment, the oxidizing agent may be added after the neutralizing agent is added to the reduced solution, or the oxidizing agent and neutralizing agent may be added simultaneously to the reduced solution. In particular, it is preferable to add the neutralizing agent after the oxidizing agent is added to the reduced solution. For example, if an oxidizing agent is added to a reduced solution that has a high pH due to the addition of a neutralizing agent, iron contained as an impurity will not be sufficiently oxidized, and Fe(OH) 3 In this case, the precipitate (iron precipitate) will not be generated and separation of impurities may be insufficient.

[0075] ≪3. How to recover valuable metals from used lithium-ion batteries≫ This article describes a method for recovering valuable metals from waste lithium-ion batteries (waste LIBs). In this method, the waste LIBs are reduced and heated to melt, the resulting molten material is sulfurized to obtain a sulfide containing copper and nickel and / or cobalt (dry processing step), and the sulfide is leached with acid to obtain a leachate (wet processing step).

[0076] This method is characterized in that sulfides containing copper and nickel and / or cobalt obtained by dry processing of waste LIBs are pulverized to produce pulverized sulfides with a particle size of 800 μm or less, and the pulverized sulfides are leached with acid under conditions in which a sulfiding agent coexists. In this way, nickel and / or cobalt can be selectively separated from the sulfides containing copper and nickel and / or cobalt, making it possible to effectively recover valuable metals contained in the waste LIBs. These processes are similar to those described in the sulfide processing method described above. EXAMPLES

[0077] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0078] [Example 1] Waste lithium-ion batteries (waste LIBs) were heated and melted to reduce them, and the resulting molten material was then sulfurized by adding a sulfurizing agent to obtain a sulfide containing copper, nickel, and cobalt. This sulfide was then used as the processing target to separate the copper, nickel, and cobalt contained in the sulfide.

[0079] (Crushing process) First, sulfide containing copper, nickel, and cobalt was pulverized by a jaw crusher and a vibration mill to obtain pulverized sulfide having a particle size of 800 μm or less. The particle size of the pulverized sulfide is the average particle size measured by a laser diffraction scattering method using a particle size distribution measuring device (Shimadzu Corporation, SALD-7000). Table 1 below shows the metal grade obtained by analyzing the obtained pulverized sulfide using an ICP analyzer.

[0080] [Table 1]

[0081] (Leaching process) Next, sufficient sulfuric acid was prepared to leach the nickel in the pulverized sulfide and the pulverized sulfide. A sulfurizing agent (sulfur) was added in an amount equivalent to the amount of copper contained in the pulverized sulfide, and the pulverized sulfide was subjected to an acid leaching treatment with a slurry concentration of 100g / L under the condition that the sulfurizing agent coexists with the pulverized sulfide. The leachate was analyzed using an ICP analyzer. The analytical values ​​(g / L) of each elemental component are shown in Table 2.

[0082] (Reduction process) After the leaching was completed, the solid-liquid separation was performed, and the resulting leachate was reduced using a reducing agent (nickel sulfide), and then filtered to separate the solid and liquid, obtaining a filtrate (reduced liquid). This reduced liquid was analyzed using an ICP analyzer. The analytical values ​​(g / L) of each elemental component are shown in Table 2.

[0083] (oxidation neutralization process) Next, 30% hydrogen peroxide (oxidizing agent) was added to the reduced solution, and then a caustic soda solution (neutralizing agent) was added after the hydrogen peroxide (oxidizing agent) to set the oxidation-reduction potential (ORP) to 400mV or more with a silver-silver chloride electrode as the reference electrode, and the pH to 4 or more, for oxidation and neutralization. After the reaction, filtration was performed to separate the solid and liquid, and a filtrate (neutralized liquid) was obtained. This filtrate (neutralized liquid) was analyzed using an ICP analyzer. The analytical values ​​(g / L) of each elemental component are shown in Table 2.

[0084] [Table 2]

[0085] As can be seen from Table 2, the Cu concentration in the leachate was sufficiently low at 3 g / L. This shows that copper can be efficiently and selectively separated from nickel and cobalt by subjecting pulverized sulfides of a predetermined particle size containing nickel and / or cobalt and copper to an acid leaching treatment in the presence of a sulfiding agent.

Claims

1. A method for treating sulfides containing copper and nickel and / or cobalt, comprising the steps of: A pulverization step of subjecting the sulfide to a pulverization treatment to obtain pulverized sulfide having a particle size of 800 μm or less; A leaching step of subjecting the pulverized sulfide to an acid leaching treatment in the presence of a sulfiding agent to obtain a leachate; a reduction step of reducing the leachate using a metal less noble than copper; an oxidation / neutralization step of adding an oxidizing agent to the solution obtained in the reduction step to control the ORP (with silver / silver chloride as a reference electrode) to a range of 380 mV to 430 mV and adding a neutralizing agent to control the pH to a range of 3.8 to 4.5, thereby obtaining a solution containing nickel and / or cobalt; Including, Methods for treating sulfides.

2. In the leaching step, a leaching treatment is performed with at least one acid selected from sulfuric acid, hydrochloric acid, and nitric acid to obtain a leachate. The method for treating sulfides according to claim 1.

3. The oxidizing agent is at least one selected from hydrogen peroxide and hypochlorous acid. The method for treating sulfides according to claim 1 or 2.

4. The neutralizing agent is at least one selected from sodium hydroxide and potassium hydroxide. The method for treating sulfides according to any one of claims 1 to 3.

5. The sulfide is produced by adding a sulfurizing agent to a melt obtained by reducing and heating waste lithium ion batteries to sulfurize the melt. The method for treating sulfides according to any one of claims 1 to 4.

6. A method for recovering valuable metals from waste lithium ion batteries, comprising: The method includes a step of obtaining a leachate by leaching a sulfide containing copper and nickel and / or cobalt, which is produced by sulfurizing a melt obtained by reducing and heating the waste lithium ion batteries, with an acid; In the process, The sulfide is subjected to a pulverization treatment to obtain pulverized sulfide having a particle size of 800 μm or less, and the pulverized sulfide is subjected to an acid leaching treatment in the presence of a sulfiding agent; The leachate obtained by the leaching treatment is subjected to a reduction treatment using a metal less noble than copper, An oxidizing agent is added to the solution obtained by the reduction treatment to control the ORP (with silver / silver chloride as a reference electrode) to a range of 380 mV to 430 mV, and a neutralizing agent is added to control the pH to a range of 3.8 to 4.5, thereby obtaining a solution containing nickel and / or cobalt. A method for recovering valuable metals from discarded lithium-ion batteries.

7. A method for recovering valuable metals from waste lithium ion batteries, comprising: A dry treatment process in which the melt obtained by reducing and heating the waste lithium ion batteries is sulfurized to obtain a sulfide containing copper and nickel and / or cobalt; A wet treatment step of subjecting the sulfide to an acid leaching treatment, In the wet processing step, The sulfide is pulverized to obtain a pulverized sulfide having a particle size of 800 μm or less, The pulverized sulfide is subjected to an acid leaching treatment in the presence of a sulfiding agent; The leachate obtained by the leaching treatment is subjected to a reduction treatment using a metal less noble than copper, An oxidizing agent is added to the solution obtained by the reduction treatment to control the ORP (with silver / silver chloride as a reference electrode) to a range of 380 mV to 430 mV, and a neutralizing agent is added to control the pH to a range of 3.8 to 4.5, thereby obtaining a solution containing nickel and / or cobalt. A method for recovering valuable metals from discarded lithium-ion batteries.

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