A copper removal agent and its preparation method, and a copper removal method thereof.

Abstract

This invention provides a copper removal agent and its preparation method, as well as a copper removal method, belonging to the field of wet recycling technology for cathode materials of waste ternary lithium-ion batteries. The copper removal agent of this invention is prepared from sulfide slag generated during the recycling of waste batteries. This copper removal agent has a small particle diameter and a large specific surface area, a loose crystal structure, and excellent activation performance. Using this copper removal agent to remove copper from the battery recycling leachate results in an excellent copper removal rate.

Description

Technical Field

[0001] This invention relates to the field of wet recycling technology for cathode materials of waste ternary lithium-ion batteries, and in particular to a copper removal agent and its preparation method and copper removal method. Background Technology

[0002] In recent years, sales of lithium-ion battery-powered vehicles have surged in my country. However, due to their limited lifespan, the number of discarded power batteries is increasing. It is predicted that by 2027, the amount of discarded ternary cathode materials and lithium iron phosphate cathode materials will reach 690,000 tons and 265,400 tons respectively. Therefore, the recycling of used lithium-ion batteries deserves particular attention.

[0003] Currently, the recycling of valuable metals from spent lithium-ion batteries is mainly divided into two types: pyrometallurgical processing and hydrometallurgical processing. Hydrometallurgical processing for recycling valuable metals from spent batteries has the advantages of being environmentally friendly and having a high recovery rate of valuable metals. It is widely used both domestically and internationally and is the mainstream process for recycling spent batteries.

[0004] The wet leaching process involves leaching metal ions from the cathode materials of spent batteries using a suitable acidic or alkaline medium. Valuable metals such as lithium, cobalt, and manganese are then obtained through precipitation, organic extraction, separation, and purification. During the leaching process, copper foil from the battery cathode materials inevitably dissolves into the leachate. The effectiveness of removing this copper directly affects the quality of the final product. Furthermore, because ternary cathode materials contain Ni, Ni metal components are also present in the leachate from spent batteries.

[0005] For the separation and purification of Cu in leachate, the main methods used in my country's smelting production are solvent extraction and chemical precipitation. Among these, the sulfide precipitation method for removing copper is relatively simple, low-cost, and a more mature process. Typically, battery recycling companies use excess sodium sulfide for copper removal, with the main chemical reaction as follows: Cu... 2+ +Na₂S==CuS+2Na + In addition to CuS, some of the nickel in the leaching solution also enters the sulfide slag in the form of nickel sulfide in the final sulfide slag obtained from the copper removal process.

[0006] With the increasing volume of waste battery recycling, a huge amount of sulfide slag is generated during the production process. Without recycling, the valuable metals contained in it result in a significant waste of resources. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a copper removal agent comprising NiS, NiS2 and CuS, which has excellent copper removal efficiency.

[0008] Another objective of this invention is to provide a method for preparing a copper removal agent, which is made from sulfide slag generated during the recycling of waste batteries.

[0009] Another object of the present invention is to provide a method for removing copper.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A copper removal agent comprising NiS, NiS2, and CuS.

[0012] The solubility product of NiS and CuS is as follows: Ksp(CuS)=9*10 -35 Ksp(NiS) = 2.8 * 10 -18 Therefore, Cu exhibits a stronger affinity for sulfur than Ni, so this portion of NiS in the copper removal agent can be used to precipitate copper, achieving a good copper removal effect.

[0013] Preferably, the copper removal agent comprises the following components by weight percentage:

[0014] NiS 62.5~71.3%, NiS 25.5~10.3%, CuS 13.2~18.4%, Cu 2~4.5%, C 0.5~1.8%.

[0015] The copper removal agent of the present invention is prepared from sulfide slag containing nickel and copper and activated carbon. In addition to NiS, NiS2 and CuS components, the copper removal agent also contains a small amount of Cu and C.

[0016] Preferably, the average particle size of the copper removal agent is 40–80 μm.

[0017] Preferably, the copper removal agent has a specific surface area of ​​320–500 m². 2 / g.

[0018] The copper removal agent of this invention is granular, with a small particle diameter and a large specific surface area, a loose crystal structure, and excellent activation performance. The average particle size of the copper removal agent is 40–80 μm, and the specific surface area is 320–500 m². 2 / g.

[0019] This invention also protects a method for preparing the above-mentioned copper removal agent, comprising the following steps:

[0020] S1. Activated carbon and sulfide slag containing nickel and copper are mixed at a mass ratio of 1:(1~5) and then ball-milled to obtain powder;

[0021] S2. Disperse the powder obtained in step S1 into a sulfuric acid solution to prepare a slurry;

[0022] S3. Spray dry the slurry obtained in step S2 to obtain spray-dried material;

[0023] S4. The spray-dried material obtained in step S3 is calcined under inert gas protection to obtain the copper removal agent.

[0024] In sulfide slag containing nickel and copper, nickel exists in the form of NiS and copper exists in the form of CuS.

[0025] Preferably, the copper content in the sulfidation slag is 7-15%, and the nickel content is 50-60%.

[0026] In the preparation method of the copper removal agent of the present invention, activated carbon and sulfide slag are first mechanically activated by ball milling. Mechanical activation can, on the one hand, make the particle size of sulfide slag finer, effectively increasing its specific surface area; on the other hand, it can also increase the deformation and defects of the internal lattice of the material, causing various dislocations and amorphization, thereby increasing the energy storage and internal energy of the material and improving its reactivity; in addition, it can also cause the redistribution of ions in the anion and cation superlattice. For sulfide slag, when the crystal size is small enough and the mechanical impact force is large enough, it can cause crystal structure distortion, leading to distortion of physicochemical properties.

[0027] Based on mechanical activation, the powder is slurried using sulfuric acid solution. Slurrying ensures thorough mixing of the sulfide slag, carbon powder, and sulfuric acid, which is beneficial for subsequent spray drying and calcination processes. Furthermore, in the presence of sulfuric acid, the sulfide slag and carbon powder form a series of sulfides after subsequent high-temperature reactions, enhancing the activity of sulfur atoms in nickel sulfide, facilitating the activation of nickel sulfide for copper deposition, and simultaneously reducing it to produce elemental copper.

[0028] Spray drying removes most of the solvent from the slurry. Simultaneously, it creates a double-pore structure in the material, increasing its specific surface area and resulting in a larger reaction area. The short processing time of spray drying ensures the activity of sulfur ions and does not damage the crystal structure.

[0029] The spray-dried material is calcined under an inert gas atmosphere. The calcination process can reduce CuS under certain conditions, partially converting it into elemental copper, thus reducing the acid dissolution reaction of copper sulfide in the subsequent copper removal process.

[0030] Preferably, in step S1, the mass ratio of activated carbon to sulfide slag is 1:(4-5).

[0031] Preferably, in step S1, the conditions for ball milling are: ball-to-material mass ratio of (5-8):1, ball milling speed of 300-500 r / min, and ball milling time of 120-180 min.

[0032] During the ball milling process, stainless steel balls with diameters of 5 mm and 3 mm can be used. Optionally, the weight ratio of the 5 mm and 3 mm stainless steel balls is 1:1.

[0033] Preferably, the average particle size of the sulfide slag is 90–120 μm. The sulfide slag is ball-milled to a mesh size of 700–1000.

[0034] Preferably, in step S2, the concentration of the sulfuric acid solution is 50–100 g / L.

[0035] Preferably, in step S2, the mass ratio of the powder to the sulfuric acid solution is 0.8 to 1.2:1.

[0036] Preferably, in step S3, the spray drying conditions are: inlet air temperature 150-200℃, outlet air temperature 60-100℃, and time 5-20s.

[0037] Optionally, the spray drying can be performed using an atomizer (spray gun). During the spray drying process, the slurry is atomized into mist particles by the atomizer, which directly contact the hot air for heat exchange, completing the drying of the slurry in a short time.

[0038] Preferably, in step S4, the calcination treatment is carried out at a temperature of 650–850°C for a time of 60–90 min.

[0039] This invention also protects a copper removal method, comprising the following steps:

[0040] Add the above copper removal agent to a solution containing copper ions and stir at 70-90°C for 60-120 minutes to remove copper;

[0041] The amount of copper removal agent added is 1.0 to 1.3 times the theoretical amount of copper ions in the solution, depending on the concentration of copper ions in the solution.

[0042] Optionally, in the copper removal method, the stirring speed is 200-500 r / min.

[0043] The main chemical reactions between copper removal agents and copper ions include:

[0044] Cu 2+ +NiS=CuS+Ni 2+ ;2Cu + +NiS=Cu2S+Ni 2+ Cu 2+ +NiS2=CuS2+Ni 2+ .

[0045] The copper-containing solution can be an leaching solution of the battery's positive electrode material.

[0046] Optionally, the copper ion content in the copper-containing solution is 500–4000 mg / L.

[0047] Compared with the prior art, the beneficial effects of the present invention are:

[0048] This invention develops a copper removal agent, its preparation method, and a copper removal method. The copper removal agent is prepared from sulfide slag generated during the recycling of waste batteries. This copper removal agent has a small particle diameter and a large specific surface area, a loose crystal structure, and excellent activation performance. Using this copper removal agent to remove copper from the battery recycling leachate results in an excellent copper removal rate. Attached Figure Description

[0049] Figure 1 The XRD pattern of the sulfide slag used in Example 1;

[0050] Figure 2 SEM image of the sulfide slag used in Example 1;

[0051] Figure 3 Here is a SEM image of the copper removal agent prepared in Example 1;

[0052] Figure 4 The graph shows the changes in copper removal rate of the copper removal agent prepared in Example 1 and the sulfide slag used in Example 1 at different addition ratios.

[0053] Figure 5 The graph shows the change in copper concentration of the copper remover prepared in Example 1 at different addition ratios. Detailed Implementation

[0054] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments do not limit the present invention in any way.

[0055] The sulfide slag used in this invention is taken from the copper removal process of wet smelting sulfide, with an average particle size of 98 μm, a copper content of 11.2%, and a nickel content of 54.6%.

[0056] Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in this technical field. Unless otherwise specified, all reagents and materials used in this invention are commercially available.

[0057] Example 1

[0058] This embodiment provides a copper removal agent, the preparation method of which is as follows:

[0059] S1. Activated carbon and sulfide slag are mixed at a mass ratio of 1:5 and then ball-milled to obtain powder;

[0060] The conditions for ball milling were as follows: stainless steel balls with diameters of 5 mm and 3 mm were used in a weight ratio of 1:1, the ball-to-material mass ratio was 6:1, the ball milling speed was 400 r / min, and the ball milling time was 150 min.

[0061] S2. Disperse the powder obtained in step S1 into a 60 g / L sulfuric acid solution to prepare a slurry. The mass ratio of powder to sulfuric acid solution is 1:1.

[0062] S3. Spray dry the slurry obtained in step S2 to obtain spray-dried material;

[0063] The conditions for spray drying are: inlet air temperature 180℃, outlet air temperature 80℃, and time 10s.

[0064] S4. The spray-dried material obtained in step S3 is calcined under nitrogen protection at a temperature of 750°C for 70 minutes to obtain activated particles, which are the copper removal agent.

[0065] Example 2

[0066] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0067] In step S1, activated carbon and sulfide slag are mixed at a mass ratio of 1:4.

[0068] Example 3

[0069] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0070] In step S1, activated carbon and sulfide slag are mixed at a mass ratio of 1:2.

[0071] Example 4

[0072] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0073] In step S1, activated carbon and sulfide slag are mixed at a mass ratio of 1:1.

[0074] Comparative Example 1

[0075] This comparative example provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0076] In step S1, activated carbon and sulfide slag are mixed at a mass ratio of 1:7.

[0077] Comparative Example 2

[0078] This comparative example provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0079] In step S1, activated carbon and sulfide slag are mixed at a mass ratio of 1:0.5.

[0080] Example 5

[0081] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0082] In step S1, the conditions for ball milling are as follows: stainless steel balls with diameters of 5 mm and 3 mm are used in a weight ratio of 1:1, the ball material mass ratio is 5:1, the ball milling speed is 300 r / min, and the ball milling time is 180 min.

[0083] Example 6

[0084] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0085] In step S1, the conditions for ball milling are as follows: stainless steel balls with diameters of 5 mm and 3 mm are used in a weight ratio of 1:1, the ball-to-material mass ratio is 8:1, the ball milling speed is 500 r / min, and the ball milling time is 120 min.

[0086] Example 7

[0087] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0088] In step S2, the concentration of the sulfuric acid solution is 100 g / L, and the mass ratio of the powder to the sulfuric acid solution is 0.8:1.

[0089] In step S3, the spray drying conditions are: inlet air temperature 150℃, outlet air temperature 60℃, and time 20s.

[0090] Example 8

[0091] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0092] In step S3, the spray drying conditions are: inlet air temperature 200℃, outlet air temperature 100℃, and time 5s.

[0093] Example 9

[0094] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0095] In step S4, the calcination temperature is 850℃ and the time is 60min.

[0096] Example 10

[0097] This embodiment provides a copper removal agent, the preparation method of which differs from that of Example 1 in that:

[0098] In step S4, the calcination temperature is 650℃ and the time is 90min.

[0099] The copper removal agents prepared in Examples 1 to 10 of this invention all satisfy the following component contents: NiS 62.5-71.3%, NiS 25.5-10.3%, CuS 13.2-18.4%, Cu 2-4.5%, and C 0.5-1.8%.

[0100] Comparative Example 3

[0101] This comparative example provides a copper removal agent, the preparation method of which is as follows:

[0102] S1. Activated carbon and sulfide slag are mixed at a mass ratio of 1:5 and then dispersed in a 60 g / L sulfuric acid solution for pulping. The mass ratio of powder to sulfuric acid solution is 1:1 to obtain the pulp.

[0103] S2. Spray dry the slurry obtained in step S1 to obtain spray-dried material;

[0104] The conditions for spray drying are: inlet air temperature 180℃, outlet air temperature 80℃, and time 10s.

[0105] S3. The spray-dried material obtained in step S3 is calcined under nitrogen protection at a temperature of 750°C for 70 minutes to obtain a copper removal agent.

[0106] The difference from Example 1 is that the activated carbon and sulfide slag are mixed and then directly pulped without ball milling.

[0107] Comparative Example 4

[0108] This comparative example provides a copper removal agent, the preparation method of which is as follows:

[0109] S1. Activated carbon and sulfide slag are mixed at a mass ratio of 1:5 and then ball-milled to obtain powder;

[0110] The conditions for ball milling were as follows: stainless steel balls with diameters of 5 mm and 3 mm were used in a weight ratio of 1:1, the ball-to-material mass ratio was 6:1, the ball milling speed was 400 r / min, and the ball milling time was 150 min.

[0111] S2. Disperse the powder obtained in step S1 into a 60 g / L sulfuric acid solution to prepare a slurry. The mass ratio of powder to sulfuric acid solution is 1:1.

[0112] S3. Place the slurry obtained in step S2 in an oven and dry it at 180°C for 2 hours to obtain the dried material;

[0113] S4. The dried material obtained in step S3 is calcined under nitrogen protection at a temperature of 750°C for 70 minutes to obtain a copper removal agent.

[0114] The difference from Example 1 is that the spray drying in step S3 is replaced by drying.

[0115] Performance testing

[0116] (1) The sulfide slag used in Example 1 and the copper removal agent prepared were subjected to XRD and / or SEM analysis. Figure 1 The images show the XRD pattern and SEM image of the sulfided slag used in Example 1. Figure 3 This is a SEM image of the copper removal agent prepared in Example 1.

[0117] It can be seen that the sulfide slag contains copper sulfide and nickel sulfide. Using the sulfide slag as raw material, the copper removal agent prepared by the method of this invention has a smaller particle size, a larger specific surface area, and a looser crystal structure compared to the sulfide slag. The average particle size of the copper removal agent is 40–80 μm, and the specific surface area is 320–500 m². 2 / g.

[0118] (2) The copper removal performance of the copper removal agents obtained in the above embodiments and comparative examples was characterized. The specific test items, test methods and results are as follows:

[0119] Positive electrode powder from a waste battery recycling company in Hunan Province was taken. The main phase of the positive electrode powder is LiCoO2. The positive electrode powder was leached with a mixture of H2SO4 and H2O2 to remove Fe and Al. The concentrations of each component in the leachate are shown in Table 1. In addition to the main metals Ni, Co and Mn, the leachate also contains impurity Cu.

[0120] Table 1. Main components of the leachate (g / L)

[0121]

[0122] (2.1) Take the copper removal agents prepared in Examples 1 to 10 and Comparative Examples 1 to 4 respectively, add them to the leaching solution at a rate of 4 g / L, and carry out copper removal. The reaction temperature is 85℃, the stirring speed is 300 r / min, and the reaction time is 90 min. The concentration of each component in the leaching solution after copper removal is measured again.

[0123] The copper removal agent prepared in Example 1 was used for copper removal, and the concentrations of each component in the leachate after copper removal are shown in Table 2.

[0124] Table 2. Main components of the leachate after copper removal (g / L)

[0125]

[0126] As can be seen, after using the copper removal agent of Example 1 to remove copper from the leachate, the Cu content decreased from 1600 mg / L to 3.2 mg / L, and the copper removal rate was 99.8%.

[0127] The copper removal rates of the copper removal agents in Examples 1-10 and Comparative Examples 1-4 are shown in Table 3.

[0128] Table 3. Copper removal rates of copper removal agents used in Examples 1-10 and Comparative Examples 1-4

[0129] Copper removal rate (%) Copper removal rate (%) Example 1 99.8 Example 8 92.4 Example 2 92.6 Example 9 87.9 Example 3 83.5 Example 10 95.7 Example 4 74.1 Comparative Example 1 52.4 Example 5 89.4 Comparative Example 2 68.7 Example 6 93.5 Comparative Example 3 72.4 Example 7 89.6 Comparative Example 4 45.3

[0130] As can be seen from the test results in Table 3, the copper removal agents prepared in each embodiment have a high copper removal rate when used to remove copper from the leachate, with some embodiments achieving a copper removal rate of over 90%.

[0131] According to Examples 1-4 and Comparative Examples 1 and 2, in step S1, the mass ratio of activated carbon to sulfide slag has a significant impact on the copper removal effect of the copper removal agent. When the mass ratio of activated carbon to sulfide slag is in the range of 1:(1-5), the copper removal rate is above 74%, and the copper removal rate in Examples 1 and 2 can reach above 90%. As the content of activated carbon relatively increases and the content of sulfide slag relatively decreases, the copper removal rate of the copper removal agent shows a downward trend. However, the inventors found that when the proportion of activated carbon is too low, the copper removal effect of the copper removal agent will also decrease significantly, with the copper removal rate in Comparative Example 1 being only 52.4%. This is because the proportion of activated carbon is too low, resulting in insufficient roasting and reducing atmosphere, thereby affecting the reduction effect of sulfide slag containing copper and nickel.

[0132] (2.2) Take the copper removal agent and sulfide slag prepared in Example 1 and add them to the leachate according to different addition ratios to remove copper. The reaction temperature is 85℃, the stirring speed is 300r / min, and the reaction time is 90min. The copper content in the leachate after copper removal is detected again, and the copper removal rate is calculated.

[0133] The addition ratio refers to the theoretical amount of copper removal agent required to reduce the copper ions in the leachate, calculated based on the concentration of copper ions in the leachate. The addition ratio = actual addition amount / theoretical amount.

[0134] Figure 4 This is a graph showing the changes in copper removal rate of copper removal agent and sulfide slag at different addition ratios in Example 1; Figure 5 The graph shows the change in copper concentration of the copper remover in Example 1 at different addition ratios.

[0135] It can be seen that the copper removal efficiency of sulfide slag is very poor; even with an addition ratio of 1.3, the copper removal rate is only 31.6%. The copper removal agent prepared using sulfide slag as raw material through the preparation method of this invention significantly improves its copper removal efficiency.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a copper removal agent, characterized by, The copper removing agent includes NiS, NiS2 and CuS, the average particle size of the copper removing agent is 40-80 μm, the specific surface area of the copper removing agent is 320-500 m 2 / g, and the preparation method comprises the following steps: S1. mixing activated carbon and sulfidation slag containing nickel and copper according to a mass ratio of 1: (4-5) and then performing ball milling treatment to obtain a powder; the ball milling treatment is performed under the following conditions: a ball-to-powder mass ratio of (5-8):1, a ball milling speed of 300-500 r / min, and a ball milling time of 120-180 min; S2. dispersing the powder obtained in step S1 into a sulfuric acid solution to prepare a slurry; the concentration of the sulfuric acid solution is 50-100 g / L, and the mass ratio of the powder to the sulfuric acid solution is (0.8-1.2):1; S3. performing spray drying on the slurry obtained in step S2 to obtain a spray-dried material; S4. performing calcination treatment on the spray-dried material obtained in step S3 under the protection of an inert gas to obtain the copper removal agent.

2. The method of claim 1, wherein the copper removal agent is prepared by the steps of: The copper removal agent comprises the following components by weight percentage: NiS 62.5-71.3%, NiS2 5.5-10.3%, CuS 13.2-18.4%, Cu 2-4.5%, and C 0.5-1.8%.

3. The method of claim 1, wherein the copper removal agent is prepared by the steps of: In step S3, the spray drying is performed under the following conditions: an inlet air temperature of 150-200 ℃, an outlet air temperature of 60-100 ℃, and a time of 5-20 s.

4. The method of claim 1, wherein the copper removal agent is prepared by the steps of: In step S4, the calcination treatment is performed at a temperature of 650-850 ℃ for a time of 60-90 min.

5. The method of claim 1, wherein the copper removal agent is prepared by the steps of: The average particle size of the sulfidation slag is 90-120 µm.

6. A method of removing copper, characterized by, The method comprises the following steps: adding the copper removal agent to a solution containing copper ions, stirring at 70-90 ℃ for 60-120 min to remove copper; wherein according to the concentration of copper ions in the solution, the amount of the copper removal agent added is 1.0-1.3 times the theoretical amount of reducing copper ions in the solution; The copper removal agent is prepared by the method for preparing the copper removal agent according to any one of claims 1-5.

7. A copper removal agent prepared by the method for preparing the copper removal agent according to any one of claims 1-5.

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