Method for producing metal cobalt from waste iron-cobalt alloy
By atomizing and powdering and oxidizing leaching of scrap iron and cobalt alloy, combined with P507 extraction and ammonium carbonate back-extraction methods, the problems of large inorganic acid consumption and low cobalt leaching rate in traditional recycling methods are solved, and efficient cobalt-iron separation and high-quality recycling products are achieved.
Patent Information
- Application Number
- CN202411664024.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-02-28
AI Technical Summary
The traditional scrap iron cobalt alloy recycling method has problems such as large consumption of inorganic acid, low cobalt leaching rate, poor quality of by-products, complex operation and large amount of extraction agents, resulting in low resource utilization and low economic benefits.
After atomizing and powdering the scrap iron cobalt alloy, the cobalt liquid and iron oxide red were obtained by oxidation leaching method, and then the cobalt iron was extracted with P507 to separate the cobalt iron. Then, the ammonium carbonate solution was used as an iron stripping agent to obtain ammonia soap P507 used for cobalt extraction, and finally obtain high-purity metal cobalt by electrodistribution.
The consumption of inorganic acid is reduced, the leaching rate of cobalt is increased, and high-quality iron oxide red and metal cobalt are obtained, the operation process is simplified, the use of the extractant is reduced, and the generation of impurities that affect the subsequent extraction effect is avoided.
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of recovering valuable metals from iron-cobalt alloys and producing metallic cobalt, and particularly relates to a method for producing metallic cobalt from waste iron-cobalt alloys. Background Art
[0002] Iron-cobalt alloy is a soft magnetic alloy with extremely high saturation magnetic induction intensity. It is mainly used in high-speed motors, rods, relays, speakers, magnetic bearings, high-performance speakers, aviation and shipping parts, and motor rotors. At the same time, the alloy is easy to machine and roll, and its economic value can be accepted by the majority of users. With the development of industry and technology, the alloy is used in high-tech fields such as the aerospace field with higher performance requirements and certain requirements for lightweight power devices. Scrap iron-cobalt alloy has high cobalt and iron contents and has a high recycling value. However, the cobalt metal content is low, the impurity iron content is high, and the material hardness is high, which is not easy to recycle.
[0003] In the field of metal recycling, the recycling of scrap iron-cobalt alloys has always been an important topic. This type of alloy has significant recycling value because it contains two valuable metal elements, iron and cobalt. However, traditional recycling methods often have many shortcomings, which limits their widespread application.
[0004] First, the traditional method of recycling scrap iron and cobalt alloy consumes a large amount of inorganic acid during the treatment process, which not only increases production costs but also may cause certain pollution to the environment. At the same time, the leaching rate of cobalt is often not high, resulting in low resource utilization.
[0005] Secondly, during the recycling process, the quality and purity of the by-products obtained, such as red iron oxide, often fail to meet market requirements, and are therefore difficult to sell directly as products, further reducing the economic benefits of recycling.
[0006] In addition, traditional recovery methods often require the use of multiple extractants when separating iron and cobalt, which not only increases the complexity of the operation, but also may lead to an increase in the amount of extractants used and an increase in costs. At the same time, in the process of stripping iron, if the stripping agent is improperly selected or improperly operated, it is easy to produce impurities such as iron hydroxide colloid, which will seriously affect the effect of subsequent cobalt extraction.
[0007] Therefore, there is an urgent need for a new method for recovering scrap iron-cobalt alloys, which can reduce the consumption of inorganic acid, improve the leaching rate of cobalt, and obtain high-quality by-products such as red iron oxide, and can simplify the operation process, reduce the use of extraction agents, and avoid the generation of impurities that affect the subsequent extraction effect. Summary of the invention
[0008] In order to solve the above problems, the present invention provides a method for producing metallic cobalt from waste iron-cobalt alloy, wherein the alloy is atomized and pulverized and then oxidized and leached, and iron impurities are extracted from the leachate with P507 to achieve the purpose of cobalt-iron separation, and then the iron-loaded organic phase is stripped with ammonium carbonate solution as an iron stripping agent, and the organic phase after stripping is ammonia soap P507, which can be used for cobalt extraction, and finally the iron and cobalt are recovered in the form of red iron oxide and metallic cobalt, respectively.
[0009] The technical solution of the present invention is as follows:
[0010] A method for producing metallic cobalt from waste iron-cobalt alloy comprises the following steps:
[0011] (1) Atomization powder making: melt the scrap iron-cobalt alloy, add flux, and use high-pressure water atomization to make powder to obtain alloy powder;
[0012] (2) Oxidative leaching: adding water to the alloy powder to prepare a slurry, adding an inorganic acid and an oxidant to perform oxidative leaching, and separating the solid and the liquid after the leaching is completed to obtain red iron oxide and cobalt liquid;
[0013] (3) Extraction of iron: the cobalt solution is mixed with P507 to extract iron, clarified, and phase separated to obtain an iron-loaded organic phase and a raffinate A;
[0014] (4) Iron stripping: adding ammonium carbonate solid to the iron-loaded organic phase, mixing and stripping, clarifying, and phase separation to obtain ammonia soap P507 and iron carbonate;
[0015] (5) Cobalt recovery: the raffinate A is mixed with the ammonia soap P507 to extract cobalt, the mixture is clarified and separated to obtain a cobalt-loaded organic phase and a raffinate B, the cobalt-loaded organic phase is mixed with an inorganic acid solution for stripping, the mixture is clarified and separated to obtain P507 after stripping of cobalt and a cobalt stripping solution; the cobalt stripping solution is deoiled with activated carbon, boric acid is added to obtain a cathode solution, and the cathode solution is subjected to electrolysis to obtain high-purity metallic cobalt.
[0016] Furthermore, in step (1), the iron-cobalt alloy powder has a cobalt content of 10-50% and an iron content of 50-90%.
[0017] Furthermore, step (1) is to melt the scrap iron-cobalt alloy at 1300-1500° C., add a flux, wherein the flux is selected from sodium sulfate or sodium chloride, and the amount of the flux is 5-15% of the weight of the alloy, and use high-pressure water atomization to obtain alloy powder, and the alloy powder particle size is -100 mesh.
[0018] Furthermore, in step (2), the inorganic acid used in the oxidation leaching is sulfuric acid or hydrochloric acid, and there is no strict requirement for its concentration, and the preferred mass concentration is 30-98%.
[0019] The oxidant is preferably any one of air, oxygen, and sodium chlorate, and its function is to oxidize the dissolved ferrous ions, thereby promoting the forward substitution reaction of metallic iron and cobalt with inorganic acid, respectively. The amount of the oxidant is preferably added according to 1.5-10 times the theoretical amount. When the amount of the oxidant is too small, the iron oxidation is incomplete, which leads to a low cobalt leaching rate. If the amount of the oxidant is too large, the cost is high.
[0020] When adding water for slurrying, it is preferably added in a liquid-to-solid mass ratio of 3-10:1. The concentration of the cobalt solution obtained by controlling the oxidation leaching is preferably 30-50g / L. If the liquid-to-solid mass ratio is too small, the leached cobalt solution is likely to crystallize. If the liquid-to-solid mass ratio is too large, a large amount of wastewater will be generated subsequently, which is likely to increase the cost of wastewater treatment.
[0021] When oxidizing and leaching cobalt, the system pH is preferably controlled at 2.5-3.5. When the pH is too low, the acid consumption is high, the amount of iron dissolved is large, and the burden of subsequent iron removal is increased. When the pH is too high, the cobalt is not completely dissolved and the recovery rate is low.
[0022] The preferred temperature for oxidative leaching of cobalt is 80-95°C. When the temperature is too low, the reaction is slow, and when the temperature is too high, the energy consumption is high.
[0023] The preferred leaching time for oxidative leaching of cobalt is 4-24 hours. If the reaction time is too short, the reaction is slow and the cobalt recovery rate is low. If the reaction time is too long, the energy consumption and recovery cost will increase.
[0024] The main reaction in step (2): (taking oxygen as the oxidant as an example) the iron and cobalt metals first undergo a replacement reaction with the inorganic acid to generate +2 valent ions and hydrogen. Due to the small amount of inorganic acid used and the order of the reaction of iron, cobalt and the inorganic acid, only part of the iron is converted into ferrous ions. As the replacement reaction proceeds, the inorganic acid is gradually consumed, the system pH reaches 2.5-3.5, and the ferrous ions are hydrolyzed to produce hydrogen ions, which promote the replacement reaction of metallic iron, cobalt and the inorganic acid. Finally, the two reactions of formula (1) and (2) reach a dynamic equilibrium, the reaction continues, and cobalt is dissolved. The ferrous hydroxide obtained by the reaction of formula (2) is unstable and generates iron oxide when the oxidant and water are heated. The progress of formula (1)-(4) promotes the forward progress of formula (5), so cobalt is continuously dissolved and the leaching rate is high. The details are as follows:
[0025] 2Fe+2H + =Fe 2+ +H2 Formula (1)
[0026] Fe 2+ +2H2O=Fe(OH)2+2H + Formula (2)
[0027] 4Fe(OH)2+O2+2H2O=4Fe(OH)3 Formula (3)
[0028]
[0029] 2Co+2H + =Co 2+ +H2 Formula (5)
[0030] Furthermore, in step (3), the temperature for extracting iron is 20-45°C, the extraction time is 5-8 min, and the pH is controlled at 2.5-3.5;
[0031] P507 is an acidic phosphine extractant. Before extracting iron, whether it is saponified or not, the pH of the raffinate must be between 2.5 and 3.5 to achieve the purpose of completely extracting iron and completely separating iron and cobalt ions.
[0032] The reaction occurs when extracting iron without saponification: 3HR+Fe 3+ =R3Fe+3H +
[0033] The volume concentration of the extractant is preferably 5-15%. When the concentration is too high, the viscosity is large, which is not conducive to phase separation. When the concentration is too low, the iron extraction effect is poor. The preferred extraction temperature is 20-45°C and the clarification time is 1-3min. When the volume concentration of the extractant is too high, the extraction temperature is too low or the clarification time is insufficient, the phase separation effect is poor, the organic phase and the aqueous phase are not completely separated, the extraction temperature is too high, the energy consumption is increased, the service life of the extraction box is shortened, and the clarification time is too long, which reduces the production efficiency.
[0034] According to the extraction order of metal ions by P507, when the solution pH is lower than 2.5, the extraction rate of iron increases with the increase of pH, and when the pH reaches 2.5, the iron extraction rate has reached the maximum (nearly 100%). When the pH is higher than 3.5, the extraction rate of cobalt by P507 increases with the increase of pH. Therefore, if you want to separate iron from cobalt by P507, you need to strictly control the pH at 2.5-3.5. When the pH is too high, the separation of cobalt and iron will be incomplete and the cobalt recovery rate will be low.
[0035] Furthermore, in step (4), during the stripping, ammonium carbonate solid is added according to an excess coefficient of 1.2-1.5, and the stripping temperature is controlled at 20-45°C, the stripping time is 5-10 min, and the clarification time is 1-3 min.
[0036] The following reactions mainly occur during stripping: 2R3Fe+3(NH4)2CO3=Fe2(CO3)3+6RNH4
[0037] Since ammonium carbonate solid is in excess during stripping, the reaction of ammonium carbonate converting the extractant into ammonia soap also occurs: 2HR+(NH4)2CO3=2RNH4+CO2+H2O
[0038] Since iron carbonate is easily hydrolyzed to form iron hydroxide colloid in the aqueous solution system, which affects the phase separation effect after iron stripping, ammonium carbonate needs to be added in solid form without introducing water, which can completely strip the iron while inhibiting the hydrolysis of iron carbonate. Iron carbonate hydrolysis reaction: Fe2(CO3)3+3H2O=2Fe(OH)3+3CO2
[0039] When the stripping temperature is too low or the clarification time is insufficient, the phase separation effect is poor; when the temperature is too high, energy consumption is increased and the service life of the extraction equipment is shortened; when the clarification time is too long, production efficiency is reduced.
[0040] When the amount of ammonium carbonate used during stripping is too little, iron stripping is incomplete. When the amount of ammonium carbonate used is too much, the production cost increases.
[0041] Furthermore, in step (5), the conditions for extracting cobalt are: extraction temperature 20-45°C, extraction time 5-10 min, and clarification time 1-3 min. The reaction occurs when extracting cobalt: 2RNH4+Co 2+ =R2Co+2NH4 + .
[0042] Furthermore, in step (5), the inorganic acid is selected from sulfuric acid or hydrochloric acid, the pH of the outlet aqueous phase is controlled to be 2.0-2.5, the cobalt stripping time is 8-10 min, the temperature is 20-45° C., and the clarification time is 1-3 min. The control conditions during the electrolytic deposition of cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, and there is no diaphragm electrolytic deposition to obtain high-purity metallic cobalt.
[0043] The reaction occurs during cobalt stripping: R2Co+2H + =Co 2+ +2HR.
[0044] Furthermore, the boric acid is added in an amount of 6 to 15 g / L, the cathode liquid pH is 1.5 to 4.0, and the control conditions for electrolytic cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, there is no diaphragm electrolytic deposition, the electrolytic cell temperature is 55 to 65 ° C, and the current density is 180 to 220 A / m 2 , isopole moment 10-15cm.
[0045] The present invention also includes an iron recovery step, wherein the iron recovery method is to calcine iron carbonate to obtain red iron oxide. When the iron carbonate is calcined, a reaction occurs: Fe2(CO3)3=Fe2O3+3CO2.
[0046] The process of the present invention is as follows Figure 1 shown.
[0047] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0048] (1) Low inorganic acid consumption and high cobalt leaching rate;
[0049] (2) The recovered red iron oxide can be directly sold as a product, and the recovered metal cobalt has a high application value;
[0050] (3) The present invention uses only one extractant to achieve step-by-step extraction and separation of iron and cobalt. Excessive iron carbonate is added during the stripping of iron, and the obtained ammonia soap P507 can be directly used for the next step of cobalt extraction. The process is simple, the operation is simple, and the amount of extractant used is small;
[0051] (4) The present invention uses ammonium carbonate solid as the iron stripping agent, which has a high iron stripping rate and can inhibit the hydrolysis reaction between iron carbonate and water, so no iron hydroxide colloid is produced, and the effect of ammonia soap P507 being subsequently used for extracting cobalt is not affected. BRIEF DESCRIPTION OF THE DRAWINGS
[0052] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION
[0053] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0054] Example 1
[0055] (1) Atomization powder making: The scrap iron-cobalt alloy is melted at 1300° C., 5% sodium sulfate by weight of the scrap iron-cobalt alloy is added as a flux, and high-pressure water atomization powder making is used to obtain iron-cobalt alloy powder. The particle size of the iron-cobalt alloy powder is -100 mesh; the cobalt content of the iron-cobalt alloy powder is 10wt% and the iron content is 90wt%.
[0056] (2) Oxidation leaching: Add water to the iron-cobalt alloy powder at a liquid-solid mass ratio of 3:1 to make a slurry, add concentrated sulfuric acid with a mass concentration of 50%, and continue to introduce air as an oxidant for oxidation leaching. When oxidizing and leaching cobalt, the pH of the system is controlled to be stable at 3.00 by the amount of sulfuric acid added, the leaching temperature is 85°C, and the leaching time is 10 hours. After the leaching is completed, the solid and liquid are separated to obtain red iron oxide and cobalt liquid. The cobalt concentration in the cobalt liquid reaches 30.06g / L, the iron concentration is 0.27g / L, the cobalt leaching rate is higher than 99%, and the iron leaching rate is less than 1%. The obtained red iron oxide can be directly sold as a product.
[0057] (3) Extraction of iron: The cobalt solution was mixed with P507 to extract iron, and the mixture was clarified and separated to obtain an iron-loaded organic phase and a raffinate A. Before extraction, P507 was not saponified, the volume concentration of P507 was 5%, the extraction temperature was 20°C, the extraction time was 10 min, the phase ratio was 5:1, and the clarification time was 3 min. After the extraction, the pH of the raffinate obtained was 2.50, the iron extraction rate was 99.99%, and the cobalt extraction rate was less than 0.5%.
[0058] (4) Iron stripping: adding ammonium carbonate solid to the iron-loaded organic phase, mixing and stripping, clarifying and separating the phases to obtain ammonia soap P507 and iron carbonate; during stripping, ammonium carbonate solid is added according to an excess coefficient of 1.2, and the stripping temperature is controlled at 20° C., the stripping time is 10 min, and the clarification time is 3 min; the ammonia soap P507 obtained in step (4) is used for the extraction of cobalt in step (5), and no iron hydroxide colloid is generated during the stripping process, and the iron stripping rate reaches more than 95%.
[0059] (5) Cobalt recovery: The raffinate A is mixed with ammonia soap P507 to extract cobalt. The extraction conditions are: extraction temperature 20°C, extraction time 10 min, phase ratio 1:1, clarification time 3 min, clarification and phase separation to obtain a cobalt-loaded organic phase and raffinate B;
[0060] The cobalt-loaded organic phase is mixed with an inorganic acid solution for stripping, clarification and phase separation. The inorganic acid is selected from sulfuric acid with a concentration of 2.5N. The pH of the outlet aqueous phase is controlled to be 2.5. The stripping time of cobalt is 10 minutes, the temperature is 20°C, the phase ratio is 3:1, and the clarification time is 3 minutes to obtain P507 after stripping cobalt and cobalt stripping solution. The cobalt stripping solution is deoiled with activated carbon, and boric acid is added at a dosage of 6g / L to obtain a cathode liquid. The cathode liquid is electrolytically deposited. The control conditions for electrolytic cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, there is no diaphragm electrolysis, the electrolytic cell temperature is 55°C, and the current density is 180A / m 2 , isopole moment 10cm, and high-purity metallic cobalt with a purity greater than 99% is obtained.
[0061] (6) Production of red iron oxide: The iron carbonate obtained in step (4) is calcined at a temperature of 280° C. for 3 h to obtain red iron oxide, which can be directly sold as a product.
[0062] Example 2
[0063] (1) Atomization powder making: The scrap iron-cobalt alloy is melted at 1400°C, and 15% sodium chloride by weight of the scrap iron-cobalt alloy is added as a flux, and high-pressure water atomization powder is used to obtain iron-cobalt alloy powder. The particle size of the iron-cobalt alloy powder is -100 mesh; the cobalt content of the iron-cobalt alloy powder is 50wt%, and the iron content is 50wt%.
[0064] (2) Oxidation leaching: Add water to the iron-cobalt alloy powder at a liquid-solid mass ratio of 10:1 to make a slurry, add concentrated hydrochloric acid with a mass concentration of 30% and an excess coefficient of 5, and slowly introduce oxygen as an oxidant for oxidation leaching. When oxidizing and leaching cobalt, the pH of the system is controlled to be stable at 3.50 by the amount of hydrochloric acid added, the leaching temperature is 95°C, and the leaching time is 4 hours. After the leaching is completed, the solid and liquid are separated to obtain red iron oxide and cobalt liquid. The cobalt concentration in the cobalt liquid reaches 39.66g / L, the iron concentration is 0.15g / L, the cobalt leaching rate is higher than 99%, and the iron leaching rate is lower than 1%. The obtained red iron oxide can be directly sold as a product.
[0065] (3) Extraction of iron: The cobalt solution was mixed with P507 to extract iron, and the mixture was clarified and separated to obtain an iron-loaded organic phase and a raffinate A. Before extraction, P507 was not saponified, the volume concentration of P507 was 10%, the extraction temperature was 30°C, the extraction time was 8 min, the phase ratio was 1.5:1, and the clarification time was 1 min. After the extraction, the pH of the raffinate obtained was 3.05, the iron extraction rate was greater than 99.99%, and the cobalt extraction rate was less than 0.5%.
[0066] (4) Iron stripping: adding ammonium carbonate solid to the iron-loaded organic phase, mixing and stripping, clarifying and separating the phases to obtain ammonia soap P507 and iron carbonate; during stripping, ammonium carbonate solid is added according to an excess coefficient of 1.5, and the stripping temperature is controlled to be 30° C., the stripping time is 8 min, and the clarification time is 2 min; the ammonia soap P507 obtained in step (4) is used for the extraction of cobalt in step (5), and no iron hydroxide colloid is generated during the stripping process, and the iron stripping rate reaches more than 95%.
[0067] (5) Cobalt recovery: The raffinate A is mixed with ammonia soap P507 to extract cobalt. The extraction conditions are: extraction temperature 30°C, extraction time 8 min, phase ratio 1:1, clarification time 2 min, clarification and phase separation to obtain a cobalt-loaded organic phase and raffinate B;
[0068] The cobalt-loaded organic phase is mixed with an inorganic acid solution for stripping, clarification and phase separation. The inorganic acid is selected from hydrochloric acid with a concentration of 2N. The pH of the outlet aqueous phase is controlled to be 2.0. The stripping time of cobalt is 8 minutes, the temperature is 30°C, the phase ratio is 2:1, and the clarification time is 2 minutes to obtain P507 after stripping cobalt and cobalt stripping solution. The cobalt stripping solution is deoiled with activated carbon, and boric acid is added at a dosage of 10g / L to obtain a cathode liquid. The cathode liquid is electrolytically deposited. The control conditions for electrolytic cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, there is no diaphragm electrolysis, the electrolytic cell temperature is 60°C, and the current density is 200A / m 2 , isopole moment 15cm, and high-purity metallic cobalt with a purity greater than 99% is obtained.
[0069] (6) Production of red iron oxide: The iron carbonate obtained in step (4) is calcined at a temperature of 400° C. for 1 h to obtain red iron oxide, which can be directly sold as a product.
[0070] Example 3
[0071] (1) Atomization powder making: The scrap iron-cobalt alloy is melted at 1500°C, and 10% sodium sulfate by weight of the scrap iron-cobalt alloy is added as a flux. The powder is made by high-pressure water atomization to obtain an iron-cobalt alloy powder. The particle size of the iron-cobalt alloy powder is -100 mesh. The cobalt content of the iron-cobalt alloy powder is 30wt%, and the iron content is 70wt%.
[0072] (2) Oxidation leaching: Add water to the iron-cobalt alloy powder at a liquid-solid mass ratio of 4.5:1 to make a slurry, add concentrated sulfuric acid with a mass concentration of 98%, and add sodium chlorate as an oxidant at an excess coefficient of 1.5 for oxidation leaching. When oxidizing and leaching cobalt, the pH of the system is controlled to be stable at 2.50 by the amount of sulfuric acid added, the leaching temperature is 80°C, and the leaching time is 24 hours. After the leaching is completed, the solid and liquid are separated to obtain red iron oxide and cobalt liquid. The cobalt concentration in the cobalt liquid reaches 49.96g / L, the iron concentration is 0.25g / L, the cobalt leaching rate is higher than 99%, and the iron leaching rate is lower than 1%. The obtained red iron oxide can be directly sold as a product.
[0073] (3) Extraction of iron: The cobalt solution was mixed with P507 to extract iron, and the mixture was clarified and separated to obtain an iron-loaded organic phase and a raffinate A. Before extraction, P507 was not saponified, the volume concentration of P507 was 15%, the extraction temperature was 45°C, the extraction time was 5 min, the phase ratio was 1:1, and the clarification time was 2 min. After the extraction, the pH of the raffinate obtained was 3.46, the iron extraction rate was greater than 99.99%, and the cobalt extraction rate was less than 0.5%.
[0074] (4) Iron stripping: adding solid ammonium carbonate to the iron-loaded organic phase, mixing and stripping, clarifying and separating the phases to obtain ammonia soap P507 and iron carbonate; during stripping, solid ammonium carbonate is added in an excess coefficient of 1.4, the stripping temperature is controlled to be 45° C., the stripping time is 5 min, and the clarification time is 1 min; the ammonia soap P507 obtained in step (4) is used for the extraction of cobalt in step (5), no iron hydroxide colloid is generated during the stripping process, and the iron stripping rate reaches more than 95%.
[0075] (5) Cobalt recovery: The raffinate A is mixed with ammonia soap P507 to extract cobalt. The extraction conditions are: extraction temperature 45°C, extraction time 5 min, phase ratio 1:1, clarification time 1 min, clarification and phase separation to obtain a cobalt-loaded organic phase and raffinate B;
[0076] The cobalt-loaded organic phase is mixed with an inorganic acid solution for stripping, clarification and phase separation. The inorganic acid is selected from sulfuric acid with a concentration of 4N. The pH of the outlet aqueous phase is controlled to be 2.33. The cobalt stripping time is 8 minutes, the temperature is 45°C, the phase ratio is 1:1, and the clarification time is 1 minute to obtain P507 after stripping and cobalt stripping solution. The cobalt stripping solution is deoiled with activated carbon, and boric acid is added at a dosage of 15g / L to obtain a cathode liquid. The cathode liquid is electrolytically deposited. The control conditions for electrolytic cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, there is no diaphragm electrolysis, the electrolytic cell temperature is 65°C, and the current density is 220A / m 2 , isopole moment 12cm, and high-purity metallic cobalt with a purity greater than 99% is obtained.
[0077] (6) Production of red iron oxide: The iron carbonate obtained in step (4) is calcined at a temperature of 360° C. for 2 h to obtain red iron oxide, which can be directly sold as a product.
[0078] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.
Claims
1. A method for producing metallic cobalt from waste iron-cobalt alloy, characterized in that: The steps include: (1) Atomization powder making: melt the scrap iron-cobalt alloy, add flux, and use high-pressure water atomization to make powder to obtain alloy powder; (2) Oxidative leaching: adding water to the alloy powder to prepare a slurry, adding an inorganic acid and an oxidant to perform oxidative leaching, and separating the solid and the liquid after the leaching is completed to obtain red iron oxide and cobalt liquid; (3) Extraction of iron: the cobalt solution is mixed with P507 to extract iron, clarified, and phase separated to obtain an iron-loaded organic phase and a raffinate A; (4) Iron stripping: adding ammonium carbonate solid to the iron-loaded organic phase, mixing and stripping, clarifying, and phase separation to obtain ammonia soap P507 and iron carbonate; (5) Cobalt recovery: the raffinate A is mixed with the ammonia soap P507 to extract cobalt, the mixture is clarified and separated to obtain a cobalt-loaded organic phase and a raffinate B, the cobalt-loaded organic phase is mixed with an inorganic acid solution for stripping, the mixture is clarified and separated to obtain P507 after stripping of cobalt and a cobalt stripping solution; the cobalt stripping solution is deoiled with activated carbon, boric acid is added to obtain a cathode solution, and the cathode solution is subjected to electrolysis to obtain high-purity metallic cobalt.
2. The method for producing metallic cobalt from waste iron-cobalt alloy according to claim 1, characterized in that: In step (1), the iron-cobalt alloy powder has a cobalt content of 10-50wt% and an iron content of 50-90wt%.
3. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: Step (1) is to melt the scrap iron-cobalt alloy at 1300-1500° C., add a flux, wherein the flux is selected from sodium sulfate or sodium chloride, and the amount of the flux is 5-15% of the weight of the alloy, and use high-pressure water atomization to obtain alloy powder, and the alloy powder particle size is -100 mesh.
4. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: In step (2), the inorganic acid is sulfuric acid or hydrochloric acid; the oxidant is air, oxygen or sodium chlorate; the liquid-to-solid mass ratio when adding water to make pulp is 3-10:1, the system pH is controlled to be 2.5-3.5, the temperature is 80-95°C, the time is 4-24h, and the amount of oxidant added is 1.5-10 times the theoretical amount.
5. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: In step (3), the temperature for extracting iron is 20-45° C., the extraction time is 5-8 min, and the pH is controlled at 2.5-3.5; the volume concentration of P507 is 5-15%, and the volume ratio of the cobalt solution to the P507 is 1:1-5:
1.
6. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: In step (4), during the stripping, ammonium carbonate solid is added according to an excess coefficient of 1.2-1.5, and the stripping temperature is controlled at 20-45° C., the stripping time is 5-10 min, and the clarification time is 1-3 min.
7. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: In step (5), the conditions for extracting cobalt are: extraction temperature 20-45° C., extraction time 5-10 min, and clarification time 1-3 min.
8. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: In step (5), the inorganic acid is selected from sulfuric acid or hydrochloric acid, the pH of the outlet aqueous phase is controlled to be 2.0-2.5, the cobalt stripping time is 8-10 min, the temperature is 20-45° C., the phase ratio is 3:1-1:1, and the clarification time is 1-3 min; the control conditions during the electrolytic deposition of cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, and there is no diaphragm electrolysis to obtain high-purity metallic cobalt.
9. The method for producing metallic cobalt from waste iron-cobalt alloy as claimed in claim 1, characterized in that: In step (5), the boric acid is added in an amount of 6 to 15 g / L, the cathode liquid pH is 1.5 to 4.0, and the control conditions for electrolytic cobalt are: the cathode is a cobalt starting plate, the anode is a titanium-plated iridium-tantalum plate, there is no diaphragm electrolytic deposition, the electrolytic cell temperature is 55 to 65°C, and the current density is 180 to 220 A / m 2 , isopole moment 10-15cm.
10. The method for producing metallic cobalt from waste iron-cobalt alloy according to claim 1, characterized in that: The method also includes an iron recovery step, wherein the iron recovery method comprises calcining iron carbonate to obtain red iron oxide.