A method for separating and recovering cobalt and nickel from an alkaline leach solution by co2 mineralization

Abstract

This invention provides a method for separating and recovering cobalt and nickel from alkaline leaching solutions via CO2 mineralization. The method includes: leaching a raw material containing cobalt and nickel in an amine complexing agent solution to obtain a leaching solution containing cobalt and nickel ion complexes; introducing CO2 into the leaching solution to perform a carbonation precipitation reaction of the metal ions; and controlling different reaction temperatures to achieve co-precipitation of cobalt and nickel or stepwise precipitation of cobalt and nickel, thereby achieving the separation and recovery of cobalt and nickel. This invention achieves the dual benefits of CO2 absorption and efficient precipitation and separation of cobalt and nickel ions, and the process is simple, significantly reducing raw material costs and environmental remediation costs.

Description

Technical Field

[0001] This invention relates to the field of metal resource recycling technology, specifically to a method for separating and recovering cobalt and nickel from alkaline leaching solutions of mineral or waste secondary resources through CO2 mineralization. Background Technology

[0002] In the recycling of secondary waste resources or the separation and extraction of mineral resources, the separation and recovery of cobalt and nickel presents many challenges for researchers due to their similar chemical properties. Cobalt, an important strategic metal often referred to as the "blue metal," is mainly used in the production of superalloys, battery cathodes, and magnetic materials. Nickel is mainly used in the manufacture of stainless steel and accounts for about two-thirds of global nickel consumption. Globally, cobalt and nickel deposits vary from country to country. For my country, most of its cobalt and nickel raw materials have long been imported, making the recovery of cobalt and nickel from secondary resources increasingly important. With the continued increase in demand for electric vehicles and the use of stainless steel as a key material, the importance of cobalt and nickel in the global economy is expected to persist.

[0003] The commonly used methods for cobalt and nickel separation and recovery in existing technologies mainly include solvent extraction, chemical precipitation, and ion exchange resin methods. Regarding solvent extraction, a method and process have emerged that utilizes carboxylic acid extractants to separate and recover nickel, cobalt, and manganese from battery intermediate solutions, achieving a Ni extraction rate greater than 99.5%. However, the use of organic reagents in solvent extraction poses significant environmental hazards, and the subsequent treatment of acidic and alkaline wastewater also increases costs. Regarding chemical precipitation, a method has emerged where waste batteries are dry-processed to obtain a nickel- and cobalt-containing copper alloy. This alloy is then contacted with nitric acid in the presence of a sulfiding agent to obtain a copper-containing solid and a leachate containing nickel and cobalt for recovery. Existing literature describes chemical precipitation as a simple process, but it does not address the separation of cobalt and nickel. Regarding ion exchange resin methods, a method for producing high-purity cobalt has emerged. This method uses m-4195 resin, which has a special adsorption effect on nickel ions, to achieve cobalt and nickel separation. However, this resin is expensive and unsuitable for large-scale industrial applications. Summary of the Invention

[0004] In view of the above problems, a method for separating and recovering cobalt and nickel from alkaline leaching solution by CO2 mineralization is provided to overcome or at least partially solve the above problems.

[0005] One object of the present invention is to provide a method for separating and recovering cobalt and nickel from alkaline leachate by leaching with an amine complexing agent combined with CO2 mineralization, which has a simple process and low recovery cost.

[0006] A further objective of this invention is to simplify the process of stepwise precipitation or co-precipitation of cobalt and nickel, thereby expanding its industrial applications.

[0007] In particular, according to embodiments of the present invention, a method for separating and recovering cobalt and nickel is provided, comprising:

[0008] Step S102: The raw material containing cobalt and nickel is immersed in an amine complexing agent solution to carry out a leaching reaction, and a leachate containing cobalt and nickel ion complexes is obtained;

[0009] Step S104: CO2 is introduced into the leachate containing the cobalt and nickel ion complex to carry out a metal ion carbonation precipitation reaction. By controlling different reaction temperatures, co-precipitation of cobalt and nickel or stepwise precipitation of cobalt and nickel can be achieved to separate and recover cobalt and nickel.

[0010] Optionally, step S104, which involves controlling different reaction temperatures to achieve co-precipitation of cobalt and nickel or stepwise precipitation of cobalt and nickel, includes:

[0011] The reaction temperature was controlled at 20-60℃ to co-precipitate cobalt and nickel ions, and the mixture of cobalt and nickel carbonate precipitate was obtained by filtration.

[0012] or,

[0013] First, the reaction temperature is controlled at 60-100℃ to precipitate cobalt ions, and the cobalt carbonate precipitate is obtained by filtration. Then, the reaction temperature is lowered to below 60℃ to precipitate nickel ions, and the nickel carbonate precipitate is obtained by filtration.

[0014] Optionally, in step S104, the ratio of the total CO2 molar concentration to the amine complexing agent molar concentration in the solution reaction system is greater than or equal to 0.5, wherein the total CO2 molar concentration is the total molar concentration of free CO2, carbonate, and bicarbonate.

[0015] Preferably, in step S104, the ratio of the total CO2 molar concentration to the amine complexing agent molar concentration in the solution reaction system is 0.7-0.9.

[0016] Optionally, in step S104, when cobalt and nickel are co-precipitated, the reaction time for cobalt and nickel co-precipitation is 2-6 hours;

[0017] When cobalt and nickel precipitate in steps, the precipitation reaction time for cobalt is 2-4 hours, and the precipitation reaction time for nickel is 2-4 hours.

[0018] Optionally, the amine complexing agent solution in step S102 is one or more of ammonia water, ammonium bicarbonate solution and ammonium carbonate solution, and the ammonia concentration of the amine complexing agent solution is 6-12M.

[0019] Optionally, step S102 specifically includes:

[0020] Raw materials containing cobalt and nickel are immersed in the amine complexing agent solution and leaching reaction is carried out at a temperature of 60-150℃, a solid-liquid ratio of 10-100g / L, and a stirring speed of 300-600rpm for 1-8h to obtain a leachate containing cobalt and nickel ion complexes.

[0021] The ratio of the total CO2 molar concentration to the molar concentration of the amine complexing agent in the solution is less than 0.5, preferably 0.2-0.4.

[0022] Optionally, step S102 further includes:

[0023] The leachate containing the cobalt and nickel ion complex was purified and impurities removed using a purifying agent;

[0024] The impurity ions in the leachate include Cu. 2+ In the case of ions, the purifying agent is a sulfide, and the sulfide reacts with Cu. 2+ The molar ratio of ions is greater than or equal to 1, the purification reaction temperature is 70-90℃, and the reaction time is 6-12h.

[0025] Optionally, after step S102 and before step S104, the method further includes step S103:

[0026] The leachate containing cobalt and nickel ion complexes obtained in step S102 is fed into the first distillation column for ammonia stripping to obtain a leachate containing cobalt and nickel ion complexes after ammonia stripping. The ammonia concentration in the leachate containing cobalt and nickel ion complexes after ammonia stripping is 2-4M.

[0027] In the process of ammonia stripping, the leachate is heated by the reboiler at the bottom of the first distillation column to evaporate the ammonia in the liquid phase into gaseous ammonia, and the gaseous ammonia is condensed by the condenser at the top of the first distillation column. The temperature of the reboiler is 80-150°C, the pressure of the reboiler is 1-5 bar, and the temperature of the condenser is 20-60°C.

[0028] Optionally, step S103 further includes:

[0029] The leachate containing cobalt and nickel ion complexes after ammonia stripping from the first distillation column is heated by exchanging heat with the leachate containing cobalt and nickel ion complexes before being fed into the first distillation column through a first heat exchanger.

[0030] Optionally, after step S104, the method further includes step S105:

[0031] The filtrate obtained after final filtration is fed into the second distillation column for CO2 desorption and amine complexing agent regeneration.

[0032] In the process of CO2 desorption and amine complexing agent regeneration, the filtrate is heated by a reboiler at the bottom of the second distillation column to generate regeneration gas, and the regeneration gas is cooled by a condenser at the top of the second distillation column. The condensed liquid phase is then refluxed back to the column body of the second distillation column to obtain a regenerated amine complexing agent solution, and the second distillation column outputs CO2. The temperature of the reboiler is 80-150°C, the pressure of the reboiler is 1-5 bar, and the temperature of the condenser is 20-60°C.

[0033] Optionally, step S105 further includes:

[0034] The filtrate to be fed into the second distillation column is split into a first input stream and a second input stream. The first input stream is directly fed into the upper part of the second distillation column, and the second input stream is fed into the second distillation column after exchanging heat with the regenerated amine complexing agent solution output from the second distillation column through a second heat exchanger. The split ratio of the first input stream to the second input stream is 20%-30%.

[0035] The method for separating and recovering cobalt and nickel provided in this invention first uses an amine complexing agent solution to leach cobalt and nickel-containing raw materials, transferring metal ions from the solid phase to the liquid phase, obtaining a leachate containing cobalt and nickel ion complexes. Then, utilizing the reaction characteristics of the amine complexing agent with CO2, CO2 is introduced into the leachate to carry out a carbonation precipitation reaction of metal ions. By controlling different reaction temperatures, co-precipitation or stepwise precipitation of cobalt and nickel can be achieved. The solution of this invention achieves the dual benefits of CO2 absorption and efficient precipitation and separation of cobalt and nickel ions, and the process is simple, greatly reducing raw material costs and environmental remediation costs.

[0036] Furthermore, in the method for separating and recovering cobalt and nickel provided in the embodiments of the present invention, the reaction temperature is controlled at 20-60℃ to co-precipitate cobalt and nickel ions, or the reaction temperature is first controlled at 60-100℃ to precipitate cobalt ions, and after filtering out the cobalt carbonate precipitate, the reaction temperature is then lowered to below 60℃ to precipitate nickel ions, thereby greatly simplifying the stepwise precipitation or co-precipitation process of cobalt and nickel and expanding its industrial application range.

[0037] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below.

[0038] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0039] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0040] Figure 1 A schematic flowchart of a method for separating and recovering cobalt and nickel according to an embodiment of the present invention is shown;

[0041] Figure 2 A schematic flowchart of a method for separating and recovering cobalt and nickel according to another embodiment of the present invention is shown;

[0042] Figure 3 A schematic flowchart of a method for separating and recovering cobalt and nickel according to yet another embodiment of the present invention is shown;

[0043] Figure 4 A schematic diagram of the apparatus used to perform step S103 according to an embodiment of the present invention is shown;

[0044] Figure 5 A schematic diagram of the apparatus used to perform step S105 according to an embodiment of the present invention is shown. Detailed Implementation

[0045] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0046] To address the aforementioned technical problems, this invention proposes a method for separating and recovering cobalt and nickel from alkaline leaching solutions via CO2 mineralization.

[0047] Figure 1 A schematic flow diagram of a method for separating and recovering cobalt and nickel according to an embodiment of the present invention is shown. See also Figure 1 As shown, the method may include at least the following steps S102 to S104.

[0048] Step S102: The raw material containing cobalt and nickel is immersed in an amine complexing agent solution for leaching reaction to obtain a leachate containing cobalt and nickel ion complexes. The raw material containing cobalt and nickel can be minerals or secondary resource waste containing cobalt and nickel metals. Through the leaching reaction with the amine complexing agent, metal ions are transferred from the solid phase to the liquid phase.

[0049] The leaching reaction for selective Co / Ni leaching in step S102 can be represented by the following reaction equation:

[0050] 2nNH3+M2O x +xH₂O→2[M(NH₃)₃] n ] x+ +2xOH -

[0051] Where M represents Co or Ni.

[0052] Step S104: CO2 is introduced into the leachate containing cobalt and nickel ion complexes to carry out a metal ion carbonation precipitation reaction. By controlling different reaction temperatures, co-precipitation of cobalt and nickel or stepwise precipitation of cobalt and nickel can be achieved to separate and recover cobalt and nickel.

[0053] The reaction equation for metal precipitation under the action of CO2 in step S104 is shown below:

[0054]

[0055] Where M represents Co or Ni.

[0056] The method for separating and recovering cobalt and nickel provided in this invention first uses an amine complexing agent solution to leach cobalt and nickel-containing raw materials, transferring metal ions from the solid phase to the liquid phase, obtaining a leachate containing cobalt and nickel ion complexes. Then, utilizing the reaction characteristics of the amine complexing agent with CO2, CO2 is introduced into the leachate to carry out a carbonation precipitation reaction of metal ions. By controlling different reaction temperatures, co-precipitation or stepwise precipitation of cobalt and nickel can be achieved. The solution of this invention achieves the dual benefits of CO2 absorption and efficient precipitation and separation of cobalt and nickel ions, and the process is simple, greatly reducing raw material costs and environmental remediation costs.

[0057] In some embodiments, the amine complexing agent solution in step S102 can be one or more of ammonia, ammonium bicarbonate solution, and ammonium carbonate solution. Specifically, the ammonia concentration of the amine complexing agent solution can be 6-12M, such as 7M, 8M, 9M, 10M, 11M, etc.

[0058] Optionally, the amine complexing agent solution in step S102 has a low CO2 loading. In this document, CO2 loading refers to the ratio of the total molar concentration of CO2 in the solution system (i.e., the total molar concentration of free CO2, carbonate, and bicarbonate) to the molar concentration of the amine complexing agent.

[0059] Specifically, the CO2 loading of the amine complexing agent solution in step S102 is less than or equal to 0.5. Preferably, the CO2 loading of the amine complexing agent solution in step S102 is in the range of 0.2-0.4.

[0060] In some specific embodiments, step S102 specifically includes: immersing a raw material containing cobalt and nickel in an amine complexing agent solution for a leaching reaction to obtain a leachate containing cobalt and nickel ion complexes. The leaching reaction temperature is 60-150℃, for example, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, or 140℃; the solid-liquid ratio is 10-100 g / L, for example, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, or 90 g / L; the stirring speed is 300-600 rpm, for example, 300 rpm, 400 rpm, 500 rpm, or 600 rpm; and the reaction time is 1-8 h, for example, 2 h, 3 h, 4 h, 5 h, 6 h, or 7 h.

[0061] In some embodiments, the operation of co-precipitating cobalt and nickel or stepwise precipitating cobalt and nickel by controlling different reaction temperatures in step S104 includes: directly controlling the reaction temperature to 20-60°C (e.g., 30°C, 40°C, 50°C) to co-precipitate cobalt and nickel ions, and filtering to obtain a cobalt and nickel mixed carbonate precipitate; or, first controlling the reaction temperature to 60-100°C (e.g., 70°C, 80°C, 90°C) to precipitate cobalt ions, filtering to obtain a cobalt carbonate precipitate, and then lowering the reaction temperature to below 60°C (e.g., 50°C, 40°C, 30°C, 20°C) to precipitate nickel ions, and filtering to obtain a nickel carbonate precipitate. The filtered precipitate is then dried to obtain a metal product.

[0062] In this embodiment, the reaction temperature is controlled at 20-60℃ to co-precipitate cobalt and nickel ions. Alternatively, the reaction temperature is first controlled at 60-100℃ to precipitate cobalt ions. After filtering out the cobalt carbonate precipitate, the reaction temperature is then lowered to below 60℃ to precipitate nickel ions. This greatly simplifies the stepwise precipitation or co-precipitation process of cobalt and nickel and expands its industrial application range.

[0063] In some preferred embodiments, the reaction temperature for co-precipitation of cobalt and nickel ions is 20-40°C.

[0064] In some preferred embodiments, the reaction temperature for cobalt ion precipitation is 70-90°C.

[0065] In some optional embodiments, in step S104, when cobalt and nickel are co-precipitated, the reaction time for cobalt and nickel co-precipitation is 2-6 hours, for example, 3 hours, 4 hours, or 5 hours.

[0066] In some alternative embodiments, in step S104, when cobalt and nickel are precipitated in steps, the precipitation reaction time for cobalt is 2-4 hours, for example, 3 hours; the precipitation reaction time for nickel is 2-4 hours, for example, 3 hours.

[0067] In some optional embodiments, in order to allow the metal ion carbonation precipitation reaction to proceed fully, a solution reaction system with a high CO2 loading is formed by introducing CO2 in step S104.

[0068] Specifically, in step S104, the CO2 loading of the solution reaction system (i.e., the ratio of the total CO2 molar concentration to the amine complexing agent molar concentration) is greater than or equal to 0.5. Preferably, the ratio of the total CO2 molar concentration to the amine complexing agent molar concentration in the solution reaction system is 0.7-0.9, for example, 0.8.

[0069] Figure 2 A schematic flowchart of a method for separating and recovering cobalt and nickel according to another embodiment of the present invention is shown. Figure 3 A schematic flow chart of a method for separating and recovering cobalt and nickel according to yet another embodiment of the present invention is shown. See also Figure 2 As shown, in some embodiments, step S102 further includes: purifying the leachate containing cobalt and nickel ion complexes obtained by leaching with a purifying agent to remove impurities, thereby improving the purity of the recovered product.

[0070] The type of purifying agent can be selected according to the type of impurities in the leachate. In some embodiments, the impurities in the leachate include Cu. 2+ In the case of ions, sulfides can be selected as purifying agents. Preferably, sulfides are combined with Cu. 2+ The molar ratio of ions is greater than or equal to 1.

[0071] The purification reaction temperature can be 70-90℃, for example 70℃, 80℃, 90℃; the reaction time is 6-12h, for example 7h, 8h, 9h, 10h, 11h, 12h.

[0072] In one specific embodiment, the sulfide and Cu 2+ The molar ratio of ions is equal to 1, that is, [S] 2- / [Cu] 2+ =1, reaction temperature is 80℃, and reaction time is 12h. Under these conditions, the precipitation rate of Cu can reach over 98%.

[0073] Continue to participate Figure 2 In some embodiments, after step S102 and before step S104, the method for separating and recovering cobalt and nickel may further include step S103: inputting the leachate containing cobalt and nickel ion complexes obtained in step S102 into the first distillation column 10 for ammonia stripping to obtain a leachate containing cobalt and nickel ion complexes after ammonia stripping. The purpose of ammonia stripping is to reduce the concentration of ammonia in the leachate. Those skilled in the art will understand that when step S102 includes a purification and impurity removal operation on the leachate, the leachate containing cobalt and nickel ion complexes obtained in step S102 is a purified and impurity-removed leachate.

[0074] Optionally, the ammonia concentration in the leachate containing cobalt and nickel ion complexes after ammonia stripping can be reduced to 2-4 M.

[0075] Figure 4 A schematic diagram of the apparatus used to perform step S103 according to an embodiment of the present invention is shown. Figure 4 As shown, the apparatus includes a first distillation column 10. A reboiler 11 is installed at the bottom of the first distillation column 10, which uses externally input steam to heat and evaporate ammonia and water in the liquid phase. Due to its high volatility, ammonia rises in gaseous form. A condenser 12 is installed at the top of the first distillation column 10 to cool the rising gas inside the column, condensing the ammonia. The column body is filled with packing or trays, which facilitate gas-liquid contact and mass transfer processes, allowing ammonia to escape from the liquid phase to the gas phase. The apparatus also includes a gas-liquid separator 13 connected to the condenser 12 for gas-liquid separation of the gas cooled by the condenser 12, thereby obtaining pure CO2 and an ammonia-CO2 mixture. The ammonia-CO2 mixture can be reused in step S102 as a leaching agent, such as... Figure 3 As shown.

[0076] Accordingly, during the ammonia stripping process in step S103, the leachate is heated by the reboiler 11 at the bottom of the first distillation column 10 to evaporate the ammonia in the liquid phase into gaseous ammonia, and the gaseous ammonia is condensed by the condenser 12 at the top of the first distillation column 10.

[0077] In some specific embodiments, the temperature of reboiler 11 is 80-150°C, more specifically 110-130°C. The pressure of reboiler 11 is 1-5 bar, more specifically 1-3 bar. The temperature of condenser 12 is 20-60°C, more specifically 35-45°C.

[0078] See also Figure 4In some further embodiments, the apparatus further includes a first heat exchanger 14 connected to the leachate inlet of the first distillation column 10 and the leachate outlet after ammonia stripping, respectively. Accordingly, step S103 may further include: exchanging heat between the leachate containing cobalt and nickel ion complexes after ammonia stripping from the first distillation column 10 and the leachate containing cobalt and nickel ion complexes preceding the first distillation column 10 via the first heat exchanger 14, thereby heating the leachate containing cobalt and nickel ion complexes preceding the first distillation column 10. Here, as... Figure 4 As shown, the leachate containing cobalt and nickel ion complexes before being fed into the first distillation column 10 can be referred to as cold ammonia-rich liquid. The leachate containing cobalt and nickel ion complexes after being heated by the first heat exchanger 14 is referred to as hot ammonia-rich liquid. The leachate containing cobalt and nickel ion complexes after ammonia stripping output from the first distillation column 10 is referred to as hot ammonia-lean liquid. The leachate containing cobalt and nickel ion complexes after ammonia stripping after being heated by the first heat exchanger 14 is referred to as cold ammonia-lean liquid. The cold ammonia-lean liquid enters step S104 for mineralization reaction.

[0079] See also Figure 2 In some embodiments, after step S104, the method for separating and recovering cobalt and nickel may further include step S105: feeding the final filtered filtrate into a second distillation column 20 for CO2 desorption and amine complexing agent regeneration.

[0080] Figure 5 A schematic diagram of the apparatus used in executing step S105 according to an embodiment of the present invention is shown. Figure 5 As shown, the apparatus includes a second distillation column 20. A reboiler 21 is located at the bottom of the second distillation column 20, which utilizes external steam heating to provide the heat required for the regeneration of the amine complexing agent. A condenser 22 is located at the top to cool the temperature of the regeneration gas from the second distillation column 20. The apparatus also includes a gas-liquid separator 23 connected to the condenser 22 for gas-liquid separation of the gas after cooling by the condenser 22. The condensed liquid phase is refluxed back to the second distillation column 20 to obtain a regenerated amine complexing agent solution, which is output from the bottom of the second distillation column 20. The gas phase separated by the gas-liquid separator 23 is high-purity CO2.

[0081] Accordingly, during the CO2 desorption and amine complexing agent regeneration process in step S104, the filtrate is heated by the reboiler 21 at the bottom of the second distillation column 20 to generate regeneration gas, and the regeneration gas is cooled by the condenser 22 at the top of the second distillation column 20. The condensed liquid phase is then refluxed back into the column body of the second distillation column 20 to obtain the regenerated amine complexing agent solution, and CO2 is output from the second distillation column 20. The regenerated amine complexing agent solution can be reused in step S102 as a leaching agent, such as... Figure 3 As shown.

[0082] In some specific embodiments, the temperature of reboiler 21 is 80-150°C, more specifically 110-130°C. The pressure of reboiler 21 is 1-5 bar, more specifically 1-3 bar. The temperature of condenser 22 is 20-60°C, more specifically 35-45°C.

[0083] See also Figure 5 In some further embodiments, the device further includes a second heat exchanger 24 connected to the filtrate inlet and the regenerated amine complexing agent solution outlet of the second distillation column 20, respectively. Accordingly, step S104 may further include: splitting the filtrate to be input into the second distillation column 20 into a first input stream and a second input stream; directly inputting the first input stream into the upper part of the second distillation column 20; and allowing the second input stream to exchange heat with the regenerated amine complexing agent solution output from the second distillation column 20 through the second heat exchanger 24 before being input into the second distillation column 20. Here, as... Figure 5 As shown, the filtrate before being fed into the second distillation column 20 can be referred to as CO2-rich liquid. The first input stream from which the CO2-rich liquid is diverted is called the diverted rich liquid. The second input stream, after being heated by heat exchange in the second heat exchanger 24, is called hot rich liquid. The regenerated amine complexing agent solution output from the second distillation column 20 is called hot lean liquid. The regenerated amine complexing agent solution after heat exchange in the second heat exchanger 24 is called CO2 lean liquid. The CO2 lean liquid enters step S102 for leaching reaction.

[0084] In some alternative embodiments, the split ratio between the first input stream and the second input stream is 20%-30%, for example 23%, 25%, or 27%.

[0085] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0086] Example 1

[0087] This embodiment provides a method for separating and recovering cobalt and nickel from the alkaline leaching solution of the anode material of a spent ternary lithium battery. The spent ternary lithium battery is a nickel-cobalt-manganese lithium battery.

[0088] The separation and recovery method includes the following steps:

[0089] Pretreatment (i.e., leaching step): The anode powder of the reduced-calcined waste ternary lithium batteries was immersed in a reaction system containing a 0.2 CO2-loaded amine complexing agent solution (2M NH4HCO3 + 8M NH3·H2O) for leaching. The reaction temperature was controlled at 80℃, the reaction time at 6 hours, the solid-liquid ratio at 50 g / L, and the magnetic stirring speed at 400 rpm to achieve selective leaching of cobalt, nickel, and copper ions. The leaching rates of cobalt, nickel, and copper ions were 97%, 98%, and 99%, respectively. Subsequently, (NH4)2S was added to the leaching solution at a concentration according to [S]. 2- / [Cu] 2+ =1 added, the precipitation rate of Cu can reach more than 98%, the reaction temperature is 80℃, and the reaction time is 12h.

[0090] Ammonia stripping: The leachate containing cobalt and nickel ion complexes after impurity removal is sent to the first distillation column 10 for ammonia stripping. The temperature of the reboiler 11 is 120°C and the pressure is 3 bar. The temperature of the condenser 12 is 40°C, so that the concentration of ammonia in the leachate is reduced to 2 M.

[0091] Precipitation: Industrial flue gas containing 10% CO2 was introduced into the solution containing metal complexes after ammonia stripping to increase the CO2 loading in the solution to 0.5. High-purity CO2 was then introduced to increase the CO2 loading in the ammonia solution to 0.8. The temperature was controlled at 40℃ in a sealed system, and the precipitation time was 6 hours to co-precipitate cobalt and nickel ions. After filtration, high-purity cobalt and nickel carbonates were obtained with yields of 96% and 97%, respectively, and purities of over 95%.

[0092] CO2 desorption and complexing agent regeneration: The high CO2 loading filtrate obtained after filtration is fed into the second distillation column 20 for CO2 desorption and amine complexing agent regeneration. Specifically, the obtained filtrate is heated to 120°C and fed into the second distillation column 20 for amine complexing agent solution regeneration at a pressure of 2 bar, obtaining high-purity CO2. The CO2 loading of the regenerated amine complexing agent solution is approximately 0.2, and then proceeds to the next leaching-precipitation-regeneration cycle process.

[0093] In this embodiment, both cobalt and nickel can be efficiently recovered simultaneously. Furthermore, the CO2 amine complexing agent solution is recycled, resulting in no wastewater generation and reducing environmental pollution and CO2 emissions. This achieves low recovery costs, high recovery rates, and high purity of the recovered products.

[0094] Example 2

[0095] This embodiment provides a method for separating and recovering cobalt and nickel from the alkaline leaching solution of nickel pyrometallurgical slag.

[0096] The separation and recovery method includes the following steps:

[0097] Pretreatment (i.e. leaching step): The nickel pyrometallurgical slag was leached in a reaction system containing an amine complexing agent solution (4M NH4HCO3 + 6M NH3·H2O) loaded with 0.4CO2. The reaction temperature was controlled at 80℃, the reaction time at 6 hours, the solid-liquid ratio in the leaching reaction at 100g / L, and the magnetic stirring speed at 400rpm to achieve selective leaching of cobalt and nickel ions, with leaching rates of 96% and 98% for cobalt and nickel, respectively.

[0098] Ammonia stripping: The leachate containing cobalt and nickel ion complexes after impurity removal is sent to the first distillation column 10 for ammonia stripping. The temperature of the reboiler 11 is 120°C and the pressure is 3 bar. The temperature of the condenser 12 is 40°C, so that the concentration of ammonia in the leachate is reduced to 2 M.

[0099] Precipitation: Industrial flue gas containing 10% CO2 was introduced into the solution containing metal complexes after ammonia stripping, raising the CO2 loading in the solution to 0.5. High-purity CO2 was then introduced to raise the CO2 loading in the ammonia solution to 0.8. The temperature was controlled at 80℃ in a sealed system, and the precipitation time was 4 hours. Cobalt precipitated first, and high-purity cobalt was obtained after filtration. Subsequently, after the temperature dropped below 60℃, nickel was carbonated and precipitated for 4 hours. After filtration, high-purity nickel was obtained with yields of 95% and 97%, respectively, and a purity of over 95%.

[0100] CO2 desorption and complexing agent regeneration: The high CO2 loading filtrate obtained after filtration is fed into the second distillation column 20 for CO2 desorption and amine complexing agent regeneration. Specifically, the obtained filtrate is heated to 120°C and fed into the second distillation column 20 for amine complexing agent solution regeneration at a pressure of 2 bar, obtaining high-purity CO2. The CO2 loading of the regenerated amine complexing agent solution is approximately 0.2, and then proceeds to the next leaching-precipitation-regeneration cycle process.

[0101] In this embodiment, cobalt and nickel can be separated and recovered to obtain high-purity cobalt and nickel carbonate products, respectively.

[0102] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0103] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A method for separating and recovering cobalt and nickel, comprising: Step S102: The raw material containing cobalt and nickel is immersed in an amine complexing agent solution to carry out a leaching reaction, and a leachate containing cobalt and nickel ion complexes is obtained; Step S104: CO2 is introduced into the leachate containing the cobalt and nickel ion complex to carry out a metal ion carbonation precipitation reaction. By controlling different reaction temperatures, co-precipitation of cobalt and nickel or stepwise precipitation of cobalt and nickel can be achieved to separate and recover cobalt and nickel.

2. The process for separation and recovery of cobalt and nickel according to claim 1, wherein, Step S104, which involves controlling different reaction temperatures to achieve co-precipitation of cobalt and nickel or stepwise precipitation of cobalt and nickel, includes the following operations: The reaction temperature was controlled at 20-60℃ to co-precipitate cobalt and nickel ions, and the mixture of cobalt and nickel carbonate precipitate was obtained by filtration. or, First, the reaction temperature is controlled at 60-100℃ to precipitate cobalt ions, and the cobalt carbonate precipitate is obtained by filtration. Then, the reaction temperature is lowered to below 60℃ to precipitate nickel ions, and the nickel carbonate precipitate is obtained by filtration.

3. The process for separation and recovery of cobalt and nickel according to claim 2, wherein, In step S104, the ratio of the total CO2 molar concentration to the amine complexing agent molar concentration in the solution reaction system is greater than or equal to 0.5, wherein the total CO2 molar concentration is the total molar concentration of free CO2, carbonate and bicarbonate. Preferably, in step S104, the ratio of the total CO2 molar concentration to the amine complexing agent molar concentration in the solution reaction system is 0.7-0.

9.

4. The method for separating and recovering cobalt and nickel according to claim 2, wherein, In step S104, when cobalt and nickel are co-precipitated, the reaction time for cobalt and nickel co-precipitation is 2-6 hours. When cobalt and nickel precipitate in steps, the precipitation reaction time for cobalt is 2-4 hours, and the precipitation reaction time for nickel is 2-4 hours.

5. The method for separating and recovering cobalt and nickel according to claim 1, wherein, The amine complexing agent solution in step S102 is one or more of ammonia water, ammonium bicarbonate solution and ammonium carbonate solution, and the ammonia concentration of the amine complexing agent solution is 6-12M.

6. The method for separating and recovering cobalt and nickel according to claim 5, wherein, Step S102 specifically includes: Raw materials containing cobalt and nickel are immersed in the amine complexing agent solution and leaching reaction is carried out at a temperature of 60-150℃, a solid-liquid ratio of 10-100g / L, and a stirring speed of 300-600rpm for 1-8h to obtain a leachate containing cobalt and nickel ion complexes. The ratio of the total CO2 molar concentration to the molar concentration of the amine complexing agent in the solution is less than 0.5, preferably 0.2-0.

4.

7. The method for separating and recovering cobalt and nickel according to claim 1, wherein, Step S102 further includes: The leachate containing the cobalt and nickel ion complex was purified and impurities removed using a purifying agent; The impurity ions in the leachate include Cu. 2+ In the case of ions, the purifying agent is a sulfide, and the sulfide reacts with Cu. 2+ The molar ratio of ions is greater than or equal to 1, the purification reaction temperature is 70-90℃, and the reaction time is 6-12h.

8. The method for separating and recovering cobalt and nickel according to any one of claims 1-7, wherein, After step S102 and before step S104, the method further includes step S103: The leachate containing cobalt and nickel ion complexes obtained in step S102 is fed into the first distillation column for ammonia stripping to obtain a leachate containing cobalt and nickel ion complexes after ammonia stripping. The ammonia concentration in the leachate containing cobalt and nickel ion complexes after ammonia stripping is 2-4M. In the process of ammonia stripping, the leachate is heated by the reboiler at the bottom of the first distillation column to evaporate the ammonia in the liquid phase into gaseous ammonia, and the gaseous ammonia is condensed by the condenser at the top of the first distillation column. The temperature of the reboiler is 80-150°C, the pressure of the reboiler is 1-5 bar, and the temperature of the condenser is 20-60°C.

9. The method for separating and recovering cobalt and nickel according to claim 8, wherein, Step S103 further includes: The leachate containing cobalt and nickel ion complexes after ammonia stripping from the first distillation column is heated by exchanging heat with the leachate containing cobalt and nickel ion complexes before being fed into the first distillation column through a first heat exchanger.

10. The method for separating and recovering cobalt and nickel according to claim 2, wherein, Following step S104, the method further includes step S105: The filtrate obtained after final filtration is fed into the second distillation column for CO2 desorption and amine complexing agent regeneration. In the process of CO2 desorption and amine complexing agent regeneration, the filtrate is heated by a reboiler at the bottom of the second distillation column to generate regeneration gas, and the regeneration gas is cooled by a condenser at the top of the second distillation column. The condensed liquid phase is then refluxed back to the column body of the second distillation column to obtain a regenerated amine complexing agent solution, and the second distillation column outputs CO2. The temperature of the reboiler is 80-150°C, the pressure of the reboiler is 1-5 bar, and the temperature of the condenser is 20-60°C.

11. The method for separating and recovering cobalt and nickel according to claim 10, wherein, Step S105 further includes: The filtrate to be fed into the second distillation column is split into a first input stream and a second input stream. The first input stream is directly fed into the upper part of the second distillation column, and the second input stream is fed into the second distillation column after exchanging heat with the regenerated amine complexing agent solution output from the second distillation column through a second heat exchanger. The split ratio of the first input stream to the second input stream is 20%-30%.

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