Raw material for pyrometallurgy, method for producing raw material for pyrometallurgy, and method for producing valuable metal using the raw material for pyrometallurgy, method for producing nickel sulfate and / or cobalt sulfate

Abstract

To provide raw material for pyrometallurgy, enabling efficient production of metal including valuable metal while suppressing a discharge amount of carbon dioxide.SOLUTION: The raw material for pyrometallurgy of the present invention includes: at least one kind of valuable metal selected from nickel (Ni) and cobalt (Co);and carbon (C), with a carbon content of 25 mass% or less, and a C / (Ni+Co) ratio of 2.5 or less. Such dry raw material for pyrometallurgy can be produced through a method that includes: a step of preparing a starting raw material including at least one kind of valuable metal, Ni or Co, and carbon; a first classification step of dividing the starting raw material into coarse powder A1 valuable metals and fine powder A2 by classification treatment; and a second classification step of separating fine powder A2 into coarse powder B1 and fine powder B2 by classification treatment. Specifically, the coarse powders A1 and B1 are collected and used as raw material the dry pyrometallurgical.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a raw material for pyrometallurgy, a method for producing a raw material for pyrometallurgy, a method for producing valuable metals using the raw material for pyrometallurgy, and a method for producing nickel sulfate and / or cobalt sulfate. [Background technology]

[0002] In recent years, as environmental regulations have become stricter, renewable energy has been attracting a great deal of attention. In particular, lithium-ion batteries have been in the spotlight as lightweight, high-power secondary batteries.

[0003] A typical lithium-ion battery has a structure in which a negative electrode material, a positive electrode material, a separator, and an electrolyte are enclosed within an outer can. For example, the outer can is made of metal such as aluminum (Al) or iron (Fe). The negative electrode material is made of a negative electrode active material (graphite, etc.) fixed to a negative electrode current collector (copper foil, etc.). The positive electrode material is made of a positive electrode active material (lithium nickel oxide, lithium cobalt oxide, etc.) fixed to a positive electrode current collector (aluminum foil, etc.). The separator is made of a porous resin film such as polypropylene. The electrolyte contains an electrolyte such as lithium hexafluorophosphate (LiPF6).

[0004] One of the main uses of lithium-ion batteries is in hybrid and electric vehicles. For this reason, it is expected that a large amount of lithium-ion batteries installed in these vehicles will be discarded in the future according to their life cycle. In addition, some lithium-ion batteries are discarded as defective products during manufacturing. There is a demand for recycling such used batteries and defective batteries generated during manufacturing (hereinafter referred to as "waste lithium-ion batteries") as resources.

[0005] As a method of recycling, a pyrometallurgical process has been proposed in which all used lithium-ion batteries are melted in a high-temperature furnace. In the pyrometallurgical process, crushed used lithium-ion batteries are melted and the valuable metals to be recovered, such as cobalt (Co), nickel (Ni), and copper (Cu), are separated and recovered from low-value-added metals, such as iron (Fe) and aluminum (Al), by utilizing the difference in oxygen affinity between them. In this method, low-value-added metals are oxidized as much as possible to produce slag, while oxidation of valuable metals is suppressed as much as possible to recover them as alloys.

[0006] For example, Patent Document 1 discloses a method for recovering valuable metals from waste lithium-ion batteries by a dry smelting process. However, the conventional dry smelting process involves burning a large amount of carbon to melt the metals, and reducing the metal oxide in a strong reducing atmosphere using the large amount of carbon, which discharges a large amount of carbon dioxide during the process. In addition, there is a possibility that the alloy of valuable metals (hereinafter also referred to as "valuable metal alloy") produced contains a large amount of impurities, which makes the process in the subsequent wet process complicated, resulting in a problem of high refining costs during valuable metal recovery.

[0007] Also, Patent Document 2 discloses a method for recovering valuable metals by a process mainly based on solvent extraction in a wet environment. However, such a processing technology using only hydrometallurgical processes still has a major problem. Specifically, in the hydrometallurgical process, a large amount of acid and neutralizing agent must be used because not only valuable metals but also impurities are dissolved in the leaching process using an acid such as sulfuric acid. Also, numerous solvent extraction steps are required to isolate each metal element. Thus, there is a problem in that the cost required for smelting for recovery is very high in the processing of recovering valuable metals using only hydrometallurgical processes.

[0008] Patent Document 3 discloses a method in which the raw materials are subjected to magnetic separation in advance to separate the magnetic materials from the non-magnetic materials, thereby recovering the magnetic materials of nickel and cobalt with a high yield and removing the non-magnetic materials of copper in advance. However, this method does not recover copper, which is a valuable metal, and requires the addition of a reducing agent required to reduce the oxidized nickel and cobalt in the subsequent dry smelting process. Furthermore, the addition of silicon dioxide or the like as a reducing agent makes the slag difficult to dissolve, and the lithium concentration in the slag decreases. From this point of view, it is preferable to use carbon as a reducing agent, but it is desirable to reduce the amount of carbon used in terms of carbon dioxide emissions.

[0009] Patent Document 4 discloses a method of roasting and crushing waste lithium-ion batteries to separate and separate valuable metals. It is known that the product obtained by this treatment contains approximately 50% by mass of valuable metals such as nickel, cobalt, and copper, and approximately 30% by mass of carbon. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2017-526820 A [Patent Document 2] JP 2020-105599 A [Patent Document 3] JP 2022-18616 A [Patent Document 4] JP 2019-171267 A Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been proposed in view of the above-mentioned conventional circumstances, and has an object to provide a raw material for pyro-smelting, a method for producing the raw material for pyro-smelting, and a method for producing valuable metals using the raw material for pyro-smelting, which can efficiently produce metals containing valuable metals while suppressing carbon dioxide emissions. [Means for solving the problem]

[0012] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, in a method for producing valuable metals contained in a raw material by reducing and melting the raw material, the inventors have focused on the carbon (C) content of the raw material (raw material for pyrometallurgy) used and the ratio expressed as C / (Ni+Co), and found that by keeping these within a specific range, it is possible to efficiently produce metals containing valuable metals while suppressing carbon dioxide emissions, thereby completing the present invention.

[0013] (1) A first aspect of the present invention is a raw material for pyrometallurgy, which contains at least one valuable metal selected from the group consisting of nickel (Ni) and cobalt (Co) and carbon (C), in which the C content is 25 mass% or less and the C / (Ni+Co) ratio is 2.5 or less.

[0014] (2) A second aspect of the present invention is a raw material for pyrometallurgy according to the first aspect of the present invention, wherein the raw material has an average particle size of 270 μm or more.

[0015] (3) A third aspect of the present invention is the raw material for pyrometallurgy smelting according to the first or second aspect, wherein the C content is 15 mass% or less.

[0016] (4) A fourth aspect of the present invention is a method for producing a raw material for dry smelting according to the first aspect of the present invention, comprising: a preparation step of preparing a starting raw material containing at least one valuable metal selected from the group consisting of nickel (Ni) and cobalt (Co) and carbon (C); a first classification step of classifying the starting raw material into coarse powder A and fine powder A containing the valuable metals; and a second classification step of classifying the fine powder A into coarse powder B and fine powder B, in which the coarse powder A obtained from the first classification step and the coarse powder B obtained from the second classification step are recovered to produce a raw material for dry smelting.

[0017] (5) A fifth aspect of the present invention is the method for producing a raw material for pyrometallurgy, according to the fourth aspect, wherein in the first classification step, classification treatment is carried out with a classification point of 50 μm to 250 μm.

[0018] (6) A sixth aspect of the present invention is the method for producing a raw material for pyrometallurgy, wherein in the second classification step, classification is performed with a classification point of 25 μm or more.

[0019] (7) A seventh aspect of the present invention is a method for producing valuable metals or alloys containing valuable metals from a raw material for pyro-smelting containing the valuable metal, the method comprising: a reduction-melting step of reducing and melting the raw material for pyro-smelting, in which the raw material for pyro-smelting according to the first aspect of the present invention is used as the raw material for pyro-smelting.

[0020] (8) An eighth aspect of the present invention is a method for producing valuable metals according to the seventh aspect of the present invention, further comprising a raw material preparation step of preparing the raw material for pyro-smelting from a starting material containing valuable metals, in which the raw material preparation step is carried out by carrying out the method according to claim 3 to prepare the raw material for pyro-smelting, and the obtained raw material for pyro-smelting is subjected to the reduction melting step.

[0021] (9) A ninth aspect of the present invention is a method for producing valuable metals according to the seventh or eighth aspect of the present invention, wherein the starting material includes detoxified battery powder obtained by burning used lithium-ion batteries to render them harmless and pulverizing them to a predetermined size.

[0022] (10) A tenth aspect of the present invention is a method for producing valuable metals according to any one of the seventh to ninth aspects of the present invention, wherein in the reducing and melting step, the raw material for dry smelting is subjected to a reducing and melting treatment in a melting furnace to obtain a reducing melt containing slag and a metal including the valuable metal.

[0023] (11) The eleventh aspect of the present invention is a method for producing nickel sulfate and / or cobalt sulfate using the raw material for pyro-smelting according to the first aspect of the invention, the method comprising: a dry treatment step of producing the valuable metal or an alloy containing the valuable metal by a dry treatment process using the raw material for pyro-smelting; and a wet treatment step of producing nickel sulfate and / or cobalt sulfate from the valuable metal or the alloy containing the valuable metal obtained in the dry treatment step through a wet treatment process including a leaching treatment with sulfuric acid.

[0024] (12) A twelfth aspect of the present invention is a method for producing nickel sulfate and / or cobalt sulfate according to the eleventh aspect of the present invention, wherein the raw material for pyrometallurgy contains nickel (Ni) and cobalt (Co), and a mixed aqueous solution of nickel sulfate and cobalt sulfate is produced through a hydroprocessing process in the hydroprocessing step.

[0025] (13) A thirteenth aspect of the present invention is the method for producing nickel sulfate and / or cobalt sulfate according to the eleventh or twelfth aspect of the present invention, wherein in the dry treatment step, the raw material for dry smelting is subjected to a reducing melting treatment in a melting furnace to obtain a reduced product containing a metal containing the valuable metal and slag, and the slag is separated from the reduced product to obtain the valuable metal or an alloy containing the valuable metal. Effect of the Invention

[0026] According to the present invention, it is possible to provide a raw material for pyro-smelting, a method for producing the raw material for pyro-smelting, and a method for producing valuable metals using the raw material for pyro-smelting, which can efficiently produce metals containing valuable metals while suppressing carbon dioxide emissions. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1 is a process diagram showing an example of a flow of a method for producing a raw material for pyrometallurgy. [Diagram 2] FIG. 1 is a process diagram showing an example of a flow of a method for producing valuable metals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 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 various modifications are possible within the scope of the present invention.

[0029] ≪1. Raw materials for dry smelting≫ (1) Raw materials for pyrometallurgy The raw material for dry smelting according to the present embodiment contains valuable metals and is a raw material for a smelting process in which the valuable metals contained in the raw material are produced by being subjected to dry processing such as reduction melting processing.

[0030] Specifically, the raw material for pyrometallurgy contains at least one valuable metal selected from nickel (Ni) and cobalt (Co), and carbon (C). The raw material for pyrometallurgy contains 25 mass% or less of C, and C / (Ni+Co) is 2.5 or less.

[0031] Such raw materials for dry smelting can reduce the amount of carbon dioxide emissions that occur during dry processes such as reduction melting and oxidation roasting. In addition, since the ratio represented by C / (Ni+Co) is 2.5 or less, valuable metals such as nickel and cobalt can be effectively reduced by dry processes, and these valuable metals can be prevented from being distributed as oxides to slag, thereby suppressing a decrease in the production yield of valuable metals.

[0032] The ratio represented by C / (Ni+Co) is preferably 1.0 or less, more preferably 0.8 or less, and even more preferably 0.6 or less. In particular, when the ratio of C / (Ni+Co) is 0.6 or less, valuable metals such as nickel and cobalt can be reduced more effectively, and reduction of impurity metals that are not the object of recovery can be suppressed, leading to a reduction in the number of steps in, for example, a wet treatment process following a dry treatment process.

[0033] The lower limit of the ratio represented by C / (Ni+Co) is preferably 0.2 or more. By making the ratio 0.2 or more, it is possible to prevent valuable metals such as nickel and cobalt from being insufficiently reduced.

[0034] As described above, the carbon (C) content is 25% by mass or less. This makes it possible to reduce the amount of carbon dioxide emitted during dry treatments such as reduction melting and oxidation roasting. The C content is preferably 20% by mass or less, and more preferably 15% by mass or less.

[0035] The lower limit of the C content is preferably 2% by mass or more. By setting the C content to 2% by mass or more, it is possible to prevent valuable metals such as nickel and cobalt from being insufficiently reduced.

[0036] The raw material for pyrometallurgy may contain metal elements other than the above-mentioned valuable metals. For example, the other metal elements include iron (Fe) and aluminum (Al). However, the Fe content in the raw material for pyrometallurgy is preferably 2 mass% or less. Also, the Al content in the raw material for pyrometallurgy is preferably 1 mass% or less. By having the Fe content and Al content preferably within the above-mentioned ranges, it is possible to suppress the generation of excessive slag through the pyrometallurgy treatment process.

[0037] Here, the raw material for pyrometallurgy preferably has an average particle size of 270 μm or more. In this specification, the average particle size refers to the average particle size measured by measuring 1000 powder particles using a laser light diffraction scattering type particle size distribution analyzer (model LA950V2) manufactured by Horiba Corporation.

[0038] Although the details will be described later, the raw material for dry smelting according to this embodiment can be produced by, for example, starting from a raw material containing a waste lithium ion battery, pulverizing the waste lithium ion battery, heating it to deactivate it, and then performing a predetermined classification process. The raw material for dry smelting is composed of the coarse powder (the powder with a larger particle size) that is separated into coarse powder and fine powder through the classification process. Such coarse powder contains a large amount of valuable metals and has a small amount of carbon (C), which is easily pulverized by pulverization.

[0039] For this reason, a raw material for dry smelting, preferably having an average particle size of 270 μm or more, stably satisfies the above-mentioned composition, i.e., the C concentration is 25 mass% or less and C / (Ni+Co) is 2.5 or less.

[0040] In this specification, the metal content is a value measured using an ICP optical emission spectrometer (model ICP-OES Agilent5900, manufactured by Agilent Technologies, Inc.), and the carbon (C) content is a value measured using a carbon-sulfur analyzer (model CS844, manufactured by LECO).

[0041] (2) Manufacturing methods for raw materials for pyrometallurgy The raw material for pyrometallurgy having the above-mentioned characteristic composition can be produced by the following method.

[0042] Fig. 1 is a process diagram showing an example of the flow of a method for producing a raw material for pyrometallurgy according to the present embodiment. The method for producing a raw material for pyrometallurgy comprises a preparation step S0 of preparing a starting material containing at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C), and a preparation step S1 of preparing (producing) a raw material for pyrometallurgy from the starting material.

[0043] The preparation step S1 for preparing the raw material for dry smelting includes a first classification step S11 for classifying the starting material into a coarse powder A1 and a fine powder A2 containing valuable metals, and a second classification step S12 for classifying the fine powder A2 obtained into a coarse powder B1 and a fine powder B2. In the preparation step S1, the coarse powder A1 obtained from the first classification step S11 and the coarse powder B1 obtained from the second classification step S12 are collected to be used as the raw material for dry smelting.

[0044] (2-1) Preparation process In the preparation step S0, a starting material containing at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C) is prepared.

[0045] The starting material is not particularly limited as long as it contains at least one valuable metal, such as nickel and cobalt, and carbon, and may be, for example, a raw material containing a waste lithium-ion battery. The waste lithium-ion battery refers to a used battery or a defective battery generated during battery manufacturing. Such a waste lithium-ion battery contains valuable metals such as nickel and cobalt as components constituting the positive electrode material, and further contains copper (Cu) as a valuable metal. In addition, the waste lithium-ion battery contains carbon as a component constituting the negative electrode material, etc.

[0046] The starting material may be a waste lithium ion battery or the like as described above, and contains at least one valuable metal, i.e., nickel and cobalt. The total content of nickel and cobalt in the starting material is not particularly limited, but is preferably 10% by mass or more, and more preferably 15% by mass or more. By producing a raw material for dry smelting from a starting material containing valuable metals in such an amount, and using the raw material for dry smelting to go through a recovery process such as a dry treatment process, valuable metals can be effectively recovered.

[0047] The starting material is not limited to waste lithium ion batteries, but may be waste electronic components containing valuable metals such as nickel and cobalt, ores, etc. The valuable metals in the starting material may be present in the form of a compound such as an oxide, or may be present in the form of an alloy. The starting material may also contain organic or inorganic substances other than those mentioned above. Furthermore, the shape of the starting material is not particularly limited, and may be a particulate shape or other shape.

[0048] For example, when raw materials containing waste lithium ion batteries are used as starting materials, in the preparation step S0, the waste lithium ion batteries constituting the starting materials are rendered harmless by burning and crushed to a predetermined size to produce a harmless battery powder. Since waste lithium ion batteries have a sealed structure and contain an electrolyte inside, there is a danger of explosion if they are crushed in their current state. Therefore, it is preferable to carry out a detoxification process in which the electrolyte is removed or deactivated by some method. The detoxification process can be carried out, for example, by burning the waste lithium ion batteries.

[0049] After the waste lithium-ion batteries are subjected to a detoxification process, the batteries are crushed into small pieces and are then classified by sieving or the like to produce powder (detoxified battery powder) with a particle size of a few mm or less. By classifying and recovering the powder with a particle size of a few mm or less by sieving or the like, a starting material with reduced amounts of excess iron (Fe) and aluminum (Al) can be obtained. In the dry treatment process, metal components such as iron and aluminum contained in the raw material are oxidized and distributed in the slag, so it is preferable that the content of these components is low from the raw material stage. The classification point in the process such as sieving in the preparation step S0 is not particularly limited, but is preferably about 3.0 mm, more preferably about 2.4 mm, and even more preferably about 1.0 mm.

[0050] (2-2) Preparation process The preparation step S1 is a step of preparing (manufacturing) a raw material for dry smelting from the prepared starting material. As shown in Fig. 1, the preparation step S1 includes a first classification step S11 in which the starting material is classified into a coarse powder A1 and a fine powder A2 containing valuable metals, and a second classification step S12 in which the obtained fine powder A2 is classified into a coarse powder B1 and a fine powder B2.

[0051] In the preparation step S1, the coarse powder A1 obtained from the first classification step S11 and the coarse powder B1 obtained from the second classification step S12 are collected and used as a raw material for pyrometallurgy.

[0052] The thus obtained raw material for pyrometallurgy contains at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C), as described above, with a C content of 25 mass% or less and a C / (Ni+Co) ratio of 2.5 or less. Therefore, according to the method for producing raw material for pyrometallurgy according to the present embodiment, it is possible to produce raw material for pyrometallurgy that can reduce the amount of carbon dioxide emitted during dry treatment such as reduction melting treatment and oxidation roasting treatment. In addition, it is possible to produce raw material for pyrometallurgy that can effectively reduce valuable metals such as nickel and cobalt by dry treatment, prevent the valuable metals from being distributed as oxides to slag, and suppress a decrease in the production yield of valuable metals.

[0053] The particle size of the powder recovered by the classification process is based on the classification point in the classification process, and the particle size of the powder does not necessarily have to be a predetermined value. Control of the particle size of the powder means control of the classification point in each classification process.

[0054] [1st classification process] In the first classification step S11, the starting material prepared in the preparation step S0 is classified at a predetermined classification point (first classification point) to separate it into a coarse powder A1 containing valuable metals and a fine powder A2.

[0055] The classification method is not particularly limited, and examples thereof include methods using a vibrating sieve, a multi-stage vibrating sieve, a dry cyclone, a wet vibrating table, an air table, an elbow jet classifier, an aero fine classifier, a dry fine powder classifier, a hydrocyclone, a concentrator, a gravity separator, a laboratory mineral separator, etc. Among these, a method using a vibrating sieve is preferred because it allows inexpensive processing and is easy to operate.

[0056] The classification point (first classification point) of the classification process in the first classification step S11 is not particularly limited and can be appropriately designed according to the composition of the starting material. Specifically, for example, the classification point is preferably set in the range of 50 μm to 250 μm, more preferably in the range of 50 μm to 150 μm, and even more preferably in the range of 75 μm to 100 μm. By setting the first classification point in the range of 50 μm to 250 μm, it is possible to effectively recover the coarse powder A1 containing valuable metals such as nickel and cobalt, thereby improving the yield, and to efficiently separate the fine powder A2 containing carbon. In addition, it is possible to improve the accuracy of the classification process in the next second classification step S12.

[0057] In the classification process in the first classification step S11, the coarse powder A1 obtained above the classification point (i.e., the sieve) is used as a raw material for dry smelting, while the fine powder A2 obtained below the classification point (i.e., the sieve) is transferred to the second classification step S12 to be classified again.

[0058] Here, the coarse powder A1 preferably has a (Ni+Co) concentration (total concentration of the valuable metals nickel and cobalt) of 40 mass % or more.

[0059] [Second classification process] In the second classification step S12, the fine powder A2 obtained below the classification point in the first classification step S11 is classified again at a predetermined classification point (second classification point), thereby separating the fine powder B1 and the fine powder B2.

[0060] The classification method is not particularly limited, and examples thereof include methods using a vibrating sieve, a multi-stage vibrating sieve, a dry cyclone, a wet vibrating table, an air table, an elbow jet classifier, an aero fine classifier, a dry fine powder classifier, a hydrocyclone, a concentrator, a gravity separator, a laboratory mineral separator, etc. Among these, the method using an elbow jet or a dry cyclone is preferable because it can more effectively and efficiently remove fine carbon.

[0061] The classification point (second classification point) of the classification process in the second classification step S12 is not particularly limited, and can be appropriately designed depending on the starting material composition, the processing result in the first classification step, and the composition of the fine powder A2. Specifically, for example, it is preferable to set the classification point at 25 μm or more, and more preferably at 30 μm or more. By setting the second classification point at 25 μm or more, it is possible to improve the quality of valuable metals such as nickel and cobalt in the coarse powder B1 obtained by separation, and to suppress the inclusion of carbon (C) in the coarse powder B1.

[0062] In the classification process in the second classification step S12, the coarse powder B1 obtained above the classification point (i.e., on the sieve) is used as a raw material for dry smelting. The coarse powder B1 may be mixed with the coarse powder A1 recovered in the first classification step S11 and used as a raw material for dry smelting, or may be used alone as a raw material for dry smelting.

[0063] On the other hand, the fine powder B2 obtained below the classification point (i.e., undersieve) contains a relatively large amount of carbon and is not very suitable as a raw material for dry smelting. However, the fine powder B2 may be subjected to magnetic separation to recover the magnetic substances such as nickel and cobalt (valuable metals remaining in the fine powder B2) and used as a raw material for dry smelting. In addition, the fine powder B2 may contain several percent of lithium, which is a valuable metal, so the fine powder B2 may be leached with acid to recover the lithium. Furthermore, as described above, the fine powder B2 has a high carbon (C) concentration, and therefore can be effectively used as a heat source or reducing agent.

[0064] The magnetic separation treatment of the fine powder B2 can be carried out by known methods such as a contact method using a permanent magnet or an electromagnet, or a non-contact method. Examples of magnetic separators used in the treatment include drum type magnetic separators and counter pole type magnetic separators. Treatment conditions such as magnetic flux density and partition position can also be designed appropriately depending on the raw material (fine powder B2). The magnetic separation treatment may be a single-stage treatment or may be multiple-stage treatment. By performing the treatment in two or more stages, carbon can be removed more effectively and valuable metals can be concentrated.

[0065] The valuable metal powders of nickel and cobalt recovered by such magnetic separation can be effectively used as raw materials for dry smelting, similar to coarse powder A1 and coarse powder B1. Although carbon is not magnetic and is not magnetized by magnetic separation, it may be mixed with nickel or cobalt in small amounts into the magnetized material. However, even if carbon is mixed into the magnetized material, it is at most about 10 mass%, and there is no problem if it is mixed with the raw materials for dry smelting (coarse powder A1, coarse powder B1).

[0066] ≪2. Manufacturing method of valuable metals using dry treatment process≫ Next, a method for producing valuable metals by a pyrochemical treatment process (pyrochemical refining process) using the above-mentioned raw materials for pyrochemical refining will be described.

[0067] Fig. 2 is a process diagram showing an example of the flow of a valuable metal production method according to the present embodiment. The valuable metal production method is a method for producing a valuable metal or an alloy (valuable metal alloy) made of the valuable metal from a dry smelting raw material containing the valuable metal. The valuable metal is at least one of nickel (Ni) and cobalt (Co).

[0068] Specifically, the method for producing valuable metals includes a reduction melting step S2 in which the raw materials for dry smelting are reduced and melted. In the reduction melting step S2, the raw materials for dry smelting are subjected to a reduction melting process in a melting furnace, thereby obtaining a reduced product (reduced molten product) containing slag and metals including valuable metals. Thereafter, in a slag separation step S3, the slag is separated from the obtained reduced product, and valuable metals or alloys containing valuable metals are recovered.

[0069] As shown in the process diagram of FIG. 2, in the method for producing valuable metals, a raw material for pyrometallurgy can be prepared via a raw material preparation step S1 in which a raw material for pyrometallurgy is prepared from a starting material containing valuable metals.

[0070] Here, the method for producing valuable metals according to the present embodiment is characterized in that the above-described detailed raw material for pyrometallurgy is used as the raw material for pyrometallurgy to be treated in the reducing and melting step S2, which is a dry treatment process. That is, the raw material for pyrometallurgy to be treated in the reducing and melting step S2 contains at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C), with a C content of 25 mass% or less and a C / (Ni+Co) ratio of 2.5 or less.

[0071] Therefore, according to the method for producing valuable metals using such raw materials for dry smelting, it is possible to reduce the amount of carbon dioxide emissions that occur during dry treatment such as reduction melting treatment. In addition, valuable metals such as nickel and cobalt can be effectively reduced by the dry treatment, and the valuable metals can be prevented from being distributed in the form of oxides to the slag, thereby suppressing a decrease in the production yield of valuable metals.

[0072] (1) Raw material preparation process As described above, the raw material for pyrometallurgy is used as the raw material for pyrometallurgy to be treated in the reduction melting step S2. Therefore, the treatment in the raw material preparation step S1 corresponds to the method for producing raw materials for pyrometallurgy described above. For this reason, the preparation step S1 in the method for producing raw materials for pyrometallurgy and the raw material preparation step S1 are both indicated by the step code "S1", and a detailed description will be omitted.

[0073] The raw material preparation step S1 is composed of a preparation step S0 for preparing a starting material containing at least one valuable metal of nickel (Ni) and cobalt (Co) and carbon (C), and a preparation step S1 for preparing (manufacturing) a raw material for dry smelting from the starting material. The preparation step S1 also includes a first classification step S11 for classifying the starting material into a coarse powder A1 and a fine powder A2 containing valuable metals, and a second classification step S12 for classifying the fine powder A2 into a coarse powder B1 and a fine powder B2.

[0074] In the raw material preparation step S1, the coarse powder A1 obtained from the first classification step S11 and the coarse powder B1 obtained from the second classification step S12 are collected and used as a raw material for pyrometallurgy.

[0075] The starting material may be a waste lithium-ion battery containing at least one of valuable metals, nickel (Ni) and cobalt (Co). When using a waste lithium-ion battery, the battery is rendered harmless by burning and crushed to a predetermined size to prepare a detoxified battery powder, which is then subjected to classification (first classification step S11, second classification step S12).

[0076] (2) Reduction melting process In the reduction melting step S2, the raw material for pyrometallurgy is charged into a melting furnace and subjected to reduction melting treatment. This produces a reduced material (reduced melt material) containing slag and metals including valuable metals. In other words, the reduction melting step S2 is a step in which a pyrometallurgy process is carried out.

[0077] Specifically, in the reduction melting process S2, in the reduction melting treatment, metal oxides and the like are reduced by heating and melting the raw materials for dry smelting to a high temperature. As a result, nickel oxide and cobalt oxide are reduced and discharged as metals (mixed metals), and valuable metals or alloys composed of such valuable metals (valuable metal alloys) are produced. Further, in the reduction melting treatment, metal elements of impurities that are not valuable metals are not reduced and are separated from the valuable metals as slag in the form of oxides. In this way, in the reduction melting treatment, while maintaining metals with low added value in the form of oxides, valuable metals (such as Ni and Co) are reduced and melted and recovered as metals.

[0078] Here, carbon (C) is a very preferable reducing agent for reducing nickel (Ni) and cobalt (Co), which are valuable metals to be recovered. For example, 1 mole of carbon can reduce 2 moles of metal oxides of valuable metals. The metals reduced by carbon are affected by the affinity between each metal and oxygen. Generally, for aluminum (Al), lithium (Li), carbon (C), manganese (Mn), phosphorus (P), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu), they are generally reduced in the order of Al < Li < C < Mn < P < Fe < Co < Ni < Cu. That is, by controlling the amount of carbon, reduction preferentially proceeds from valuable metals (such as Ni and Co).

[0079] However, the greater the amount of carbon supplied to the reduction melting treatment, the greater the amount of carbon dioxide discharged from the system through the treatment. On the other hand, if the amount of carbon is small, as described above, it is impossible to effectively reduce the oxides of valuable metals, and it becomes difficult to effectively recover them as metals.

[0080] In this regard, the present embodiment is characterized in that a raw material for pyrometallurgy containing at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C), with a C content of 25 mass% or less and a C / (Ni+Co) ratio of 2.5 or less is used as the raw material for pyrometallurgy. With such raw material for pyrometallurgy, it is possible to carry out a process that reduces the amount of carbon dioxide emissions, and since the relationship of C / (Ni+Co) of 2.5 or less is satisfied, the oxides of valuable metals can be effectively reduced.

[0081] The heating temperature in the reduction melting treatment is not particularly limited, but is preferably in the range of 1300°C to 1550°C, and more preferably in the range of 1350°C to 1450°C. At a heating temperature exceeding 1550°C, thermal energy is wasted and the refractory material in the melting furnace is rapidly worn out, which may reduce productivity. On the other hand, at a heating temperature below 1300°C, the separation of the slag and metal may be impaired, resulting in a reduction in the recovery rate.

[0082] The furnace (melting furnace) used in the reduction melting treatment is not particularly limited, and examples of the melting furnace include a submerged arc furnace, an arc furnace, and an induction furnace.

[0083] In the reduction melting process, a flux may be added to lower the melting point of the slag. Examples of the flux include calcium oxide and calcium carbonate. The flux may be added by being thrown into the melting furnace in which the raw materials for pyrometallurgy are charged, or may be mixed with the raw materials for pyrometallurgy and then added.

[0084] In addition, in the reduction melting treatment, if the degree of reduction is too high and impurity metals are also reduced and distributed to valuable metals, an oxidizing agent may be supplied to adjust the degree of oxidation. The degree of oxidation can be appropriately adjusted by a known method. For example, an oxidizing agent such as oxygen may be blown into the molten material produced by the reduction melting treatment. More specifically, a metal tube (lance) is inserted into the molten material, and the oxidizing agent is blown in by bubbling to perform the oxidation treatment. Note that the oxidizing agent used in this case may be an oxygen-containing gas, such as air, pure oxygen, or oxygen-enriched gas.

[0085] In the method for producing valuable metals, an oxidizing roasting step can be provided, as necessary, in which a part or all of the raw materials for dry smelting are oxidized and roasted prior to the treatment in the reduction melting step S2. By providing the oxidizing roasting step in this manner and carrying out the oxidizing roasting treatment, it is possible to suppress the variation in the oxidation of the metal elements contained in the raw materials for dry smelting.

[0086] In the oxidizing roasting step, it is preferable to treat (oxidizing roasting) the raw material for pyrometallurgy at an oxidation degree that can oxidize low-value metals (e.g., Al) contained in the raw material for pyrometallurgy. Meanwhile, the oxidation degree can be easily controlled by adjusting the treatment temperature, time and / or atmosphere of the oxidizing roasting.

[0087] The degree of oxidation is adjusted as follows. That is, aluminum (Al), lithium (Li), carbon (C), manganese (Mn), phosphorus (P), iron (Fe), cobalt (Co), nickel (Ni), and copper (Cu) are generally oxidized in the following order: Al>Li>C>Mn>P>Fe>Co>Ni>Cu. In the oxidation roasting process, oxidation is allowed to proceed until all of the aluminum contained in the raw material for dry smelting is oxidized. Although oxidation may be promoted until a portion of the iron is oxidized, it is preferable to keep the degree of oxidation at a level at which the cobalt is not oxidized and distributed to the slag.

[0088] The oxidizing agent used in the oxidation roasting treatment is not particularly limited, but is preferably an oxygen-containing gas (air, quasi-oxygen, oxygen-enriched gas, etc.) The supply amount of the oxidizing agent is preferably, for example, 1.2 times or more the chemical equivalent required for oxidation of each substance to be the target of the oxidation treatment.

[0089] The heating temperature in the oxidizing roasting treatment is not particularly limited, but is preferably 600° C. or higher, and more preferably 700° C. or higher. By using such a heating temperature, the heating time can be shortened. In addition, the heating temperature is preferably 900° C. or lower, which can reduce the thermal energy cost and increase the efficiency of the oxidizing roasting treatment.

[0090] The oxidation roasting treatment can be carried out using a known roasting furnace. The same furnace as the melting furnace used in the subsequent reduction melting step S2 may be used, but it is more preferable to carry out the oxidation roasting treatment using a different furnace (backup furnace). As the furnace (oxidizing roasting furnace) used in the oxidation roasting treatment, any type of furnace can be used as long as it is capable of supplying an oxidizing agent (oxygen, etc.) while roasting the charge and carrying out the oxidation treatment therein. Examples include a rotary kiln, a tunnel kiln (hearth furnace), and a fluidized bed roasting furnace.

[0091] (4) Slag separation process The slag separation step S3 is a step for separating slag from the reduction product (reduced molten product) obtained through the reduction melting step S2, and recovering valuable metals or alloys of valuable metals (valuable metal alloys). Slag and metal have different specific gravities, and slag, which has a smaller specific gravity than metal, collects above metal in the melting furnace, so that slag and metal can be efficiently separated and recovered by gravity separation.

[0092] ≪3. Method of recovering valuable metals using wet treatment process≫ The metal containing valuable metal obtained through the above-mentioned dry treatment process is, for example, an alloy containing nickel (Ni) and cobalt (Co). In addition, for example, when a dry treatment process is carried out using a waste lithium ion battery as a starting material and a dry smelting material prepared from the starting material, an alloy (Ni-Co-Cu alloy) containing copper (Cu) as a valuable metal in addition to nickel (Ni) and cobalt (Co) can be obtained. By subjecting such an alloy to a wet treatment process (wet smelting process), each valuable metal can be separated, refined, and recovered.

[0093] The wet treatment process for alloys includes leaching using an acid such as sulfuric acid, solvent extraction to extract specific impurity elements and valuable metal elements, and liquid purification to purify a solution containing valuable metals by oxidation and / or neutralization. Leaching, solvent extraction, liquid purification, etc. can be performed by known methods. By going through such wet treatment processes, the valuable metals to be recovered can be refined, concentrated, and separated and recovered.

[0094] For example, an aqueous sulfate solution of nickel (Ni) and cobalt (Co) can be produced by leaching nickel (Ni) and cobalt (Co) from an alloy (Ni-Co-Cu alloy) by adding sulfuric acid to the alloy.

[0095] Therefore, from this, it is possible to define a method for producing an aqueous nickel sulfate solution and / or an aqueous cobalt sulfate solution using the raw materials for dry smelting described in detail above. Specifically, it is possible to define a method for producing nickel sulfate and / or cobalt sulfate, comprising a dry treatment step (a step of the dry treatment process) of producing a valuable metal or an alloy containing the valuable metal by a dry treatment process using the raw materials for dry smelting, and a wet treatment step (a step of the wet treatment process) of producing nickel sulfate and / or cobalt sulfate from the valuable metal or the alloy containing the valuable metal obtained in the dry treatment step through a wet treatment process including a leaching treatment using sulfuric acid.

[0096] The nickel sulfate and / or cobalt sulfate produced by the method for producing nickel sulfate and / or cobalt sulfate conceptually includes both the form of an aqueous solution and the form of a solid.

[0097] The method of leaching with acid is not particularly limited and can be performed by a known method. For example, strong acids such as hydrochloric acid, sulfuric acid, and nitric acid are used alone or in combination, and such an acid solution is added to the alloy (alloy powder), and the pH is controlled to a range of 0.8 to 2.0 for treatment. As described above, among acids, it is preferable to use an acid containing sulfuric acid in order to realize the so-called "battery to battery" which is an ideal circulation method in which waste lithium ion batteries are recycled and used again as a lithium ion battery raw material. By using sulfuric acid as the acid, a leachate can be obtained in the form of sulfates (nickel sulfate, cobalt sulfate) which are easily usable as a positive electrode material for lithium ion batteries.

[0098] The amount of acid used in the leaching treatment is 1 equivalent or more, preferably 1.2 equivalent or more, more preferably in the range of 1.2 to 11 equivalents, based on the total amount of nickel and / or cobalt contained in the alloy. By increasing the acid concentration, the rate of the leaching reaction can be increased. As a specific example, in order to adjust the amount of acid so that the pH is 0.8 or more, it is preferable to use an amount that results in 1.2 to 2 equivalents.

[0099] In addition, in the leaching treatment, it is preferable to add a sulfurizing agent before contacting the valuable metal or an alloy containing the valuable metal with an acid, or simultaneously with contacting the valuable metal with an acid, and to carry out the leaching treatment under conditions in which the sulfurizing agent coexists. For example, when a Ni-Co-Cu alloy is to be treated, copper can be efficiently fixed as a solid sulfide by carrying out the leaching treatment in the presence of the sulfurizing agent, and the leachate in which nickel and / or cobalt are dissolved can be effectively separated from the leach residue mainly containing copper sulfide.

[0100] As the sulfurizing agent, known agents such as solid sulfur (S), sodium hydrosulfide, hydrogen sulfide, etc. The amount of the sulfurizing agent added is preferably equal to or more than the equivalent required to sulfurize the copper contained in the alloy (1 equivalent or more), and more preferably equal to or more than 1.2 equivalents.

[0101] Also, for example, in the leaching treatment of Ni-Co-Cu alloy, at least a part of the Ni-Co-Cu alloy may be sulfurized prior to the leaching treatment. Copper (Cu) is more easily sulfurized than nickel (Ni) or cobalt (Co), and preferentially becomes copper sulfide. Therefore, by sulfurizing a part of the Ni-Co-Cu alloy, a mixture of copper sulfide and Ni-Co alloy is obtained. As a result, copper is fixed as a solid, and nickel and cobalt can be selectively leached into acid. Therefore, by subjecting the Ni-Co-Cu alloy to sulfurization treatment in advance, nickel and cobalt can be more efficiently leached into acid. The method of sulfurization is not particularly limited, and examples include a method of introducing a sulfur-containing substance such as solid sulfur (S) or hydrogen sulfide (H2S) into the alloy.

[0102] When carrying out the leaching treatment, it is preferable to crush the alloy to a predetermined size in advance. By crushing, the specific surface area of ​​the alloy is increased, and the leaching efficiency can be improved. The crushing treatment is not particularly limited, and can be carried out using a known crusher such as a ball mill, a rod mill, or a disk mill. Alternatively, the alloy may be crushed by a method such as gas atomization or water atomization to prepare an atomized powder, which is then subjected to the leaching treatment.

[0103] In this way, an aqueous solution of nickel sulfate and / or cobalt sulfate can be produced by subjecting a valuable metal or an alloy containing the valuable metal to a leaching treatment with sulfuric acid. For example, when an alloy containing nickel and cobalt obtained from a dry smelting raw material containing nickel and cobalt through a dry treatment process is subjected to a leaching treatment, a mixed aqueous solution of nickel sulfate and cobalt sulfate can be produced.

[0104] The resulting leachate containing nickel and / or cobalt can then be subjected to a cleaning process including a neutralization process and a solvent extraction process, which allows impurity elements to be separated and removed, yielding an aqueous solution in which nickel and / or cobalt are concentrated.

[0105] Specifically, for example, impurity elements such as iron (Fe) and zinc (Zn) in the aqueous solution can be removed by subjecting the aqueous solution of nickel sulfate and cobalt sulfate obtained through a leaching process to a purification process, thereby making it possible to obtain an aqueous solution of nickel sulfate and cobalt sulfate in which nickel and cobalt are concentrated. In addition, by subjecting the aqueous solution after the purification process to a solvent extraction process using a predetermined extractant, nickel and cobalt can be further concentrated.

[0106] Thereafter, nickel sulfate and / or cobalt sulfate can be converted into a solid form from the aqueous solution of nickel sulfate and / or cobalt sulfate by a known method. EXAMPLES

[0107] 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.

[0108] (preparation process) Waste lithium-ion batteries containing nickel (Ni) and cobalt (Co) as valuable metals were roasted to render them harmless, pulverized, and then sieved to a classification point of 1 mm. The resulting under-sieve black mass was collected and used as the starting material.

[0109] (Preparation process) The starting material, black mass, was treated as follows to prepare a raw material for pyrometallurgy. Specifically, the starting material was first classified at the classification points (first classification points) shown in Table 1 below, and separated into coarse powder A (oversieve material) and fine powder A (undersieve material).

[0110] Next, the recovered fine powder A was subjected to a second classification process at the classification point (second classification point) shown in Table 1 below, and separated into coarse powder B (sieve-over material) and fine powder B (under-sieve material).

[0111] The coarse powder A and the coarse powder B obtained through the above-mentioned preparation process were mixed to prepare a raw material for pyrometallurgy.

[0112] The carbon (C) content and the ratio represented by C / (Ni+Co) were measured for the pyrometallurgical raw materials used in each of the Examples and Comparative Examples. The average particle size of the pyrometallurgical raw materials was also measured. The measurement results are summarized in Table 1 below.

[0113] The metal content was measured using an ICP emission spectrometer (Agilent Technologies, model ICP-OES Agilent5900). The carbon content was measured using a LECO carbon-sulfur analyzer (model CS844). The average particle size is the average particle size measured when 1,000 powder particles were measured using a Horiba laser light diffraction scattering particle size distribution analyzer (model LA950V2).

[0114] (Dry treatment process) Next, the obtained pyrochemical smelting raw material was used to carry out a pyrochemical process for producing valuable metals. Specifically, the pyrochemical smelting raw material was charged into a submerged arc furnace, heated and melted at a temperature of 1400°C, and a reduction melting process was carried out to reduce the oxides of valuable metals. This reduction melting process produced a slag consisting of oxides of impurity elements and a reduced molten material containing an alloy of nickel and cobalt.

[0115] The slag was separated from the resulting reduced melt, and an alloy of nickel and cobalt was recovered.

[0116] (Measurement of processing results) The amount of carbon dioxide (CO2) emitted by carrying out the dry treatment process was calculated by estimating that the carbon (C) used in the process that was not used for reduction was emitted as CO2. In addition, the purity of the recovered nickel-cobalt alloy (Ni-Co alloy) was measured using an ICP optical emission spectrometer (Agilent Technologies, Model ICP-OES Agilent5900). The measurement results are summarized in Table 1 below.

[0117] [Table 1]

[0118] As shown in the results in Table 1, in Examples 1 to 7, which used raw materials for dry smelting having a carbon (C) content of 25 mass% or less and a ratio expressed as C / (Ni+Co) of 2.5 or less, alloys with high purity of valuable metals could be obtained, and carbon dioxide emissions in the dry treatment process were effectively reduced.

[0119] In contrast, in Comparative Examples 1 to 3, the carbon (C) content exceeded 25 mass% and the ratio expressed as C / (Ni+Co) exceeded 2.5, so that the amount of carbon dioxide emitted in the pyroprocessing process increased compared to the Examples. In addition, an excessive reduction reaction occurred in the pyroprocessing, and even impurity elements were reduced, resulting in a low purity of the alloy.

Claims

1. Contains at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C); The C content is 25% by mass or less, C / (Ni+Co) is 2.5 or less; Raw material for dry smelting.

2. The average particle size is 270 μm or more. The raw material for pyrometallurgy according to claim 1.

3. The C content is 15% by mass or less. The raw material for pyrometallurgy according to claim 1.

4. A method for producing the raw material for pyrometallurgy according to claim 1, A preparation step of preparing a starting material containing at least one valuable metal selected from nickel (Ni) and cobalt (Co) and carbon (C); The starting material is subjected to a classification treatment to obtain a coarse powder A containing valuable metals. １ and fine powder A ２ A first classification process, The fine powder A ２ The powder is classified into coarse powder B. １ and fine powder B ２ A second classification process, having The coarse powder A obtained from the first classification step １ and the coarse powder B obtained from the second classification step. １ and recover them as raw materials for dry smelting. A method for producing raw materials for pyrometallurgy.

5. In the first classification step, a classification process is performed with a classification point of 50 μm to 250 μm. The method for producing a raw material for pyrometallurgy according to claim 4.

6. In the second classification step, classification is performed with a classification point of 25 μm or more. The method for producing a raw material for pyrometallurgy according to claim 5.

7. A method for producing a valuable metal or an alloy containing a valuable metal from a dry smelting raw material containing the valuable metal, comprising: A reduction and melting step of reducing and melting the raw material for pyrometallurgy, The raw material for pyrometallurgy according to claim 1 is used as the raw material for pyrometallurgy. A method for producing valuable metals.

8. A raw material preparation step of preparing the raw material for pyrometallurgy from a starting material containing valuable metals, In the raw material preparation step, the raw material for pyrometallurgy is prepared by carrying out the method according to claim 4, and the obtained raw material for pyrometallurgy is subjected to the reduction melting step. The method for producing valuable metals according to claim 7.

9. The starting material includes a detoxified battery powder obtained by burning waste lithium ion batteries to render them harmless and pulverizing them to a predetermined size. The method for producing valuable metals according to claim 7.

10. In the reduction and melting step, the raw material for dry smelting is subjected to a reduction and melting process in a melting furnace to obtain a reduction and melt product containing slag and metals including valuable metals. The method for producing valuable metals according to claim 7.

11. A method for producing nickel sulfate and / or cobalt sulfate using the raw material for pyrometallurgy according to claim 1, a dry treatment step of producing the valuable metal or an alloy containing the valuable metal by a dry treatment process using the raw material for dry smelting; a wet treatment step of producing nickel sulfate and / or cobalt sulfate from the valuable metal or an alloy containing the valuable metal obtained in the dry treatment step through a wet treatment process including a leaching treatment with sulfuric acid; A method for producing nickel sulfate and / or cobalt sulfate comprising the steps of:

12. The pyrometallurgical raw material contains nickel (Ni) and cobalt (Co), A mixed aqueous solution of nickel sulfate and cobalt sulfate is produced through the wet treatment process in the wet treatment step. The method for producing nickel sulfate and / or cobalt sulfate according to claim 11.

13. In the dry processing step, The raw material for dry smelting is subjected to a reduction melting process in a melting furnace to obtain a reduced product containing a metal containing the valuable metal and slag, The valuable metal or an alloy containing the valuable metal is obtained by separating the slag from the reduced product. The method for producing nickel sulfate and / or cobalt sulfate according to claim 11.

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