Method for preparing nickel sulfate solution by using residual nickel anodes
Through multi-step treatment of nickel residual electrodes, a high-concentration nickel sulfate solution was prepared, which solved the problem of unutilized nickel residual electrodes and nickel supplementary pressure in nickel electrolysis process, and achieved low-cost and efficient nickel-cobalt recycling and environmentally friendly flue gas Governance.
Patent Information
- Application Number
- CN202411260570.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2024-12-27
AI Technical Summary
The nickel residual electrodes are not fully utilized in the existing nickel electrolysis process, resulting in high production costs and low nickel-cobalt yields. The anode sludge produced by the nickel residual electrode treatment increases the flue gas treatment pressure of the pyrometallurgical furnace, and there is a supplementary effect. Nickel notch requires a high concentration of nickel sulfate solution.
Through the steps of crushing, sieving, rod milling, ball milling, acid adjustment, normal pressure leaching and pressurized oxygen leaching, high concentration nickel sulfate solution is prepared to reduce the nickel content of anode sludge and iron removal slag, and directly used for use in Nickel electrolytic system supplements nickel to reduce the environmental pressure of pyrometallurgy process.
The process flow is shortened, production costs are reduced, nickel-cobalt yield is improved, the environmental pressure of flue gas treatment of pyrometallurgical furnace kilns is eliminated, and the efficient utilization of nickel residual electrodes is achieved.
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Figure CN119194101A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of nonferrous hydrometallurgy and relates to a method for preparing a nickel sulfate solution by utilizing nickel residual electrodes. Background Art
[0002] In the soluble anode diaphragm electrolysis process of nickel, while the electrolytic nickel is produced, there is still about 23% of the nickel residual electrode that is not fully utilized by the electrolysis. In this regard, the existing process is to return this part of the nickel residual electrode to the nickel melting and secondary casting anode plate for reuse, but this method has the disadvantages of long process, high production cost, and low nickel and cobalt yield. At the same time, the anode mud attached to the nickel residual electrode enters the pyrometallurgical furnace, which increases the SO2 content of the flue gas and creates greater environmental pressure on flue gas treatment. In addition, there is a nickel filling gap in the nickel electrolytic production process, which requires a high-concentration nickel sulfate solution for nickel filling. Therefore, it is of great significance to explore a short-process, low-cost, high-yield, and zero-emission process route for the optimization of nickel residual electrode treatment. Summary of the invention
[0003] The purpose of the present invention is to provide a method for preparing nickel sulfate solution by using nickel residual anode to solve the problems existing in the prior art, so as to prepare a relatively pure high-concentration nickel sulfate solution to supplement nickel for the nickel electrolysis system and alleviate the pressure of nickel supplementation.
[0004] To this end, the present invention adopts the following technical solutions: A method for preparing a nickel sulfate solution using nickel residual anode comprises the following steps: Step a, crushing nickel anode scraps: crushing the nickel anode scraps produced by nickel electrolysis in two stages, and at the same time, removing the anode mud attached to the surface of the nickel anode scraps to separate the copper ear wires from the nickel anode scraps; Specifically, the particle size of the nickel residual electrodes after crushing in step a is ≤10 mm.
[0005] Step b, nickel anode butt screening: The nickel anode butt is crushed into nickel anode butt blocks, and the copper ear wire, anode mud and nickel anode butt are separated and graded and screened. The copper ear wire is used as the screen over material, and the anode mud is used as the screen under material to separate from the nickel anode butt blocks, so as to reduce the Cu in the nickel sulfate solution. 2+ The nickel anode scraps are discharged as the sieve, the nickel anode scraps with a particle size of more than 25mm are returned for crushing and secondary treatment, the copper ear wire is recovered as copper raw material, and the anode mud is sent for washing; Specifically, in step b, the anode mud removal rate is ≮90%, and the copper ear wire separation rate is ≮95%.
[0006] Step c, slurry preparation: nickel residual anode blocks with a particle size of ≤25 mm are fed into a rod mill for rod grinding, and the nickel residual anode particles produced by the rod grinding are finely ground in a ball mill. After fine grinding, the slurry is equipped with a spiral slurry separator. Under the action of the spiral slurry separator, components with larger particle sizes move downward in the axial direction and outward in the radial direction at the same time under the action of the cyclone field, and move downward along the wall of the device when reaching the cone section of the spiral slurry separator, and are discharged from the bottom flow port, and return to the ball mill for further fine grinding, and components with smaller particle sizes of the slurry move toward the central axis, and form an upwardly moving inner vortex at the center of the axis, and are then discharged from the overflow port and sent to the slurry for acidification; Specifically, in step c, the rod mill grinding time is controlled at 20 to 40 minutes, the particle size of the output nickel residual anode particles is ≤5 mm, the mass percentage concentration of the ore pulp finely ground by the ball mill is 75 to 85%, the fine grinding time is 20 to 30 minutes, the pH value of the ore pulp is between 6 and 7, and the particle size of the nickel residual anode after fine grinding is ≤-280 mesh ≥90%.
[0007] Step d, slurry acidification: after adding iron removal tailings washing liquid and anode mud washing liquid to the prepared slurry according to the slurry liquid-to-solid mass ratio, add an appropriate amount of sulfuric acid; Specifically, in step d, the slurry liquid-solid mass ratio of the slurry is 1:6-8, the slurrying time is 0.5-1h, the slurry acid content is 15-40g / l, and the pre-slurry liquid contains 3-8g / l Cu.
[0008] Step e, atmospheric pressure leaching: introducing an appropriate amount of compressed air or industrial pure oxygen, controlling the reaction time and temperature, leaching out the alloy phases and oxides of nickel, cobalt, copper, etc. contained in the nickel anode scrap as much as possible, converting Ni3S2 into NiS, dissolving and leaching out all the copper ear wire fragments entrained in the nickel anode scrap, and ensuring that Cu in the leaching system is 2+ and Cu + Cycle balance; In step e, the reaction temperature is 70-90°C, and the amount of compressed air introduced is 50-120 Nm 3 / h, the reaction time is 6 to 10 hours, and the pH value of the slurry at the end point of normal pressure leaching is 2.0 to 3.0.
[0009] Step f, pressurized oxygen leaching: After atmospheric pressure leaching, the ore pulp enters the autoclave for further reaction, and sufficient oxidant is added. The reaction pressure, temperature and time are controlled to leach out nickel as much as possible, precipitate iron in the form of hematite, and precipitate most of Cu 2+ Under the inhibition of nitrogen in compressed air, it is not leached and enters and exits the iron removal slag in the form of CuS. After pressurized oxygen leaching, the slurry is separated by liquid and solid to obtain a relatively pure nickel sulfate solution. At the same time, the iron removal tailings by-product is produced; In step f, the oxidant is compressed air, and the amount of compressed air introduced is 500-2000 Nm 3 / h, vapor phase temperature is 155-165℃, autoclave pressure is 1.4-1.6MPa, reaction time is 6-8h, pH value of ore pulp at the end of pressure leaching is 1.5-2.5, nickel sulfate solution Ni 2+ ≥120g / l, Cu 2+ ≤1g / l, Fe 2+ ≤3g / l.
[0010] Step g, countercurrent washing: the iron removal tailings produced by pressurized oxygen leaching are continuously countercurrent washed, and the mass ratio of leaching water to the iron removal tailings is controlled to obtain iron removal slag with low Ni content and high Fe content. The iron removal slag is sold and processed as an iron raw material. After the iron removal tailing washing liquid is enriched with Ni, the returned ore pulp is acidified to utilize the residual acid and recover nickel; In the step g, the mass ratio of rinsing water to iron removal tailings is 1:10-12, the washing temperature is 20-35°C, the washing time is 1-2h, the iron removal slag contains Ni<1% and Fe≥53%, and the recycled iron removal tailings washing liquid has Ni≥40g / l.
[0011] Step h, anode mud washing: the anode mud screened out from the nickel residual anode is subjected to multi-stage slurry washing according to the slurry liquid-solid mass ratio, and the washed nickel residual anode fine particles are prepared for use in the return ore slurry, and after the anode mud washing liquid is enriched with Ni, the return ore slurry is acidified to utilize the residual acid and recover nickel, and the washed anode mud is sent to hot melt sulfur extraction to prepare elemental sulfur and enrich precious metals; Specifically, the liquid-to-solid mass ratio of the slurry washing in step h is 1:3-4, the washing temperature is 20-35°C, the washing time is 1-2h, and the anode mud washing liquid Ni is recycled. 2+ ≥40g / l, the Ni content of anode mud after washing is <0.5%.
[0012] The beneficial effects of the present invention are: The present invention changes the existing pyrometallurgical process route for treating nickel residual electrodes, shortens the process flow, reduces production costs, improves the nickel-cobalt yield, effectively reduces the nickel content index of anode mud and iron-removing slag, eliminates the environmental pressure of pyrometallurgical furnace flue gas treatment caused by this, and directly utilizes nickel residual electrodes to prepare high-quality nickel sulfate solution to fill the nickel gap in the nickel electrolysis production system. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION
[0014] The technical solution of the present invention is described below in conjunction with the accompanying drawings and implementation methods.
[0015] Example 1 The physical state of nickel residual anode produced by a nickel electrolysis production system is: anode mud adhesion thickness ≯8mm, block diameter ≯450mm, anode mud water content 21%, and the weight percentages of its main components are: Ni 68.16%, Cu 3.97%, Fe 1.77%, Co1.07%, S 24.41%.
[0016] like Figure 1 As shown, the method for preparing nickel sulfate solution from nickel residual anode comprises the following steps: Step a. Crushing nickel anode residues: The nickel anode residues produced by nickel electrolysis are crushed in two stages by a jaw crusher. The particle size of the nickel anode residues after crushing is ≤10mm. At the same time, the anode mud attached to the surface of the nickel anode residues is removed to separate the copper ear wire and the nickel anode residues; Step b. Nickel anode residue screening: The crushed nickel anode residues are graded and screened, and the copper ear wire is used as the screen material, and the anode mud is used as the screen material to separate from the nickel anode residue blocks to reduce the Cu content in the nickel sulfate solution. 2+ and sulfate content, the anode scraps are discharged as sieves, the nickel anode scraps with a particle size of ≤10mm are sent to slurry preparation, the nickel anode scraps with a particle size of >10mm are returned for crushing and secondary treatment, the copper ear wire is recovered as copper raw material, and the anode mud is sent for washing; among them, the anode mud removal rate is 90.3%, and the copper ear wire separation rate is 95.1%; Step c. Slurry preparation: nickel anode scrap blocks with a particle size of ≤10 mm are fed into a rod mill for rod grinding. The rod grinding time is controlled at 30 min to produce nickel anode scrap particles with a particle size of ≤5 mm. Then, the nickel anode scrap particles are finely ground in a ball mill. The slurry concentration is controlled at 75%, the fine grinding time is controlled at 25 min, the slurry pH value is 6, and the nickel anode scrap particle size after fine grinding is ≤-280 mesh. After fine grinding, the slurry is separated by a spiral slurry separator, and the nickel anode scrap particle size of nickel anode scrap particles>-280 mesh components are separated and returned to the fine mill for further processing; Step d. Slurry acidification: The prepared slurry is slurried by adding iron removal tailings washing liquid and anode mud washing liquid at a slurrying liquid-solid mass ratio of 1:7 for slurrying. The slurrying time is 0.5h. After adding sulfuric acid, the acid content of the slurry reaches 26.7g / l and the Cu content reaches 5.3g / l; Step e. Normal pressure leaching: compressed air flow rate is 80Nm 3 / h, reaction time is 8h, reaction temperature is 73~81℃, and end point pH value is 2.41; the composition of atmospheric pressure leaching solution is: Ni 64.66g / l, Cu 4.33g / l, Fe 4.61g / l, Co0.38g / l; Step f. Pressurized oxygen leaching: After atmospheric pressure leaching, the slurry enters the autoclave for further reaction. The compressed air flow rate is 665Nm 3 / h, vapor phase temperature of 160 ~ 165 ℃, kettle pressure of 1.5MPa, reaction time of 7h, end point pH of 2.1, leaching nickel as much as possible, precipitating iron in the form of hematite, and leaching most of Cu 2+ Under the inhibition of nitrogen in compressed air, it is not leached and enters and exits the iron removal slag in the form of CuS. After pressurized oxygen leaching, the slurry is separated by liquid and solid to obtain a relatively pure nickel sulfate solution. At the same time, the iron removal tailings by-product is produced; the composition of the pressurized leaching solution is: Ni 130.17g / l, Cu 0.09g / l, Fe0.05g / l, Co 1.31g / l.
[0017] Step g. Countercurrent washing: The iron removal tailings produced by pressurized oxygen leaching are continuously countercurrent washed, the mass ratio of washing water to iron removal tailings is 1:10, the washing temperature is 25°C, the washing time is 2h, the iron removal slag contains 0.97% Ni and 54.3% Fe, which is sold as iron raw material, and the iron removal tailing washing liquid is recycled with Ni45.1g / l, and the returned ore pulp is acidified to utilize the residual acid and recover nickel; Step h. Anode mud washing: the anode mud screened from the nickel anode residues is slurried at a slurry liquid-solid mass ratio of 1:3, and the slurry liquid-solid mass ratio is controlled to perform multi-stage countercurrent slurry washing. The washing time is 2 hours, and the washing temperature is 25°C. The washed nickel anode residue fine particles are returned to the ore pulp for use, and the anode mud washing liquid Ni44.3g / l is recycled. The returned ore pulp is acidified to utilize the residual acid and recover nickel. The washed anode mud contains 0.47% Ni and is sent to hot melt sulfur extraction to prepare elemental sulfur and enrich precious metals.
[0018] Example 2 The physical state of nickel residual anodes produced by a nickel electrolysis production system is as follows: anode mud adhesion thickness ≯8mm, block diameter ≯450mm, anode mud water content 21%, and the weight percentages of its main components are: Ni 70.01%, Cu 3.41%, Fe 1.53%, Co1.02%, and S 24.13%.
[0019] The method for preparing nickel sulfate solution from nickel residual anode comprises the following steps: Step a. Crushing nickel anode residues: The nickel anode residues produced by nickel electrolysis are crushed in two stages by a jaw crusher. The particle size of the nickel anode residues after crushing is ≤10mm. At the same time, the anode mud attached to the surface of the nickel anode residues is removed to separate the copper ear wire and the nickel anode residues; Step b. Nickel anode residue screening: The crushed nickel anode residues are graded and screened, and the copper ear wire is used as the screen material, and the anode mud is used as the screen material to separate from the nickel anode residue blocks to reduce the Cu content in the nickel sulfate solution. 2+and sulfate content, the anode scraps are discharged as sieves, the nickel anode scraps with a particle size of ≤10mm are sent to slurry preparation, the nickel anode scraps with a particle size of >10mm are returned for crushing and secondary treatment, the copper ear wire is recovered as copper raw material, and the anode mud is sent for washing; among them, the anode mud removal rate is 90.5%, and the copper ear wire separation rate is 95.3%; Step c. Slurry preparation: nickel anode scrap blocks with a particle size of ≤10 mm are fed into a rod mill for rod grinding. The rod grinding time is controlled at 30 min to produce nickel anode scrap particles with a particle size of ≤5 mm. The slurry is then finely ground in a ball mill. The slurry concentration is controlled at 78%, the fine grinding time is 30 min, the slurry pH value is 6, and the nickel anode scrap particle size after fine grinding is ≤-280 mesh. The slurry after fine grinding is separated by a spiral slurry separator, and the nickel anode scrap particles with a particle size of >-280 mesh are returned to the fine mill for further processing; Step d. Slurry acidification: The prepared slurry is slurried by adding iron removal tailings washing liquid and anode mud washing liquid at a slurrying liquid-solid mass ratio of 1:8 for slurrying. The slurrying time is 0.5h. After adding sulfuric acid, the acid content of the slurry reaches 25.8g / l and the Cu content reaches 4.9g / l; Step e. Normal pressure leaching: compressed air flow rate is 85Nm 3 / h, reaction time is 9h, reaction temperature is 75-83℃, endpoint pH value is 2.26, and the composition of atmospheric pressure leaching solution is: Ni 65.21g / l, Cu 4.07g / l, Fe 4.23g / l, Co0.32g / l; Step f. Pressurized oxygen leaching: After atmospheric pressure leaching, the slurry enters the autoclave for further reaction. The compressed air flow rate is 700Nm 3 / h, vapor phase temperature of 160 ~ 165 ℃, kettle pressure of 1.5MPa, reaction time of 7.5h, end point pH of 2.3, leaching nickel as much as possible, precipitating iron in the form of hematite, and leaching most of Cu 2+ Under the inhibition of nitrogen in compressed air, it is not leached and enters and exits the iron removal slag in the form of CuS. After pressurized oxygen leaching, the slurry is separated by liquid and solid to obtain a relatively pure nickel sulfate solution. At the same time, the iron removal tailings by-product is produced; wherein, the pressurized leaching solution has the following components: Ni128.03g / l, Cu1g / l, Fe3g / l, Co1.29g / l; Step g. Countercurrent washing: The iron removal tailings produced by pressurized oxygen leaching are continuously countercurrent washed, the mass ratio of washing water to iron removal tailings is 1:10, the washing temperature is 27°C, the washing time is 2h, the iron removal slag contains 0.99% Ni and 53.8% Fe, and is sold as iron raw material. The recycled iron removal tailings washing liquid contains 44.9g / l Ni, and the returned ore pulp is acidified to utilize the residual acid and recover nickel; Step h. Anode mud washing: The anode mud screened from the nickel residual anode is slurried at a slurry liquid-solid mass ratio of 1:3, and the slurry liquid-solid mass ratio is controlled to perform multi-stage countercurrent slurry washing. The washing time is 2 hours and the washing temperature is 27°C. The washed nickel residual anode fine particles are returned to the ore pulp for use. The recycled anode mud washing liquid contains Ni 46.0g / l, the return pulp is acidified to utilize the residual acid and recover nickel. The anode mud contains 0.45% Ni after washing and is sent for hot melting sulfur extraction to prepare elemental sulfur and enrich precious metals.
[0020] Example 3 The physical state of nickel residual anodes produced by a nickel electrolysis production system is as follows: anode mud adhesion thickness ≯8mm, block diameter ≯450mm, anode mud water content 21%, and the weight percentages of its main components are: Ni 67.79%, Cu 3.71%, Fe 1.68%, Co1.03%, and S 24.46%.
[0021] The method for preparing nickel sulfate solution from nickel residual anode comprises the following steps: Step a. Crushing nickel anode residues: The nickel anode residues produced by nickel electrolysis are crushed in two stages by a jaw crusher. The particle size of the nickel anode residues after crushing is ≤10mm. At the same time, the anode mud attached to the surface of the nickel anode residues is removed to separate the copper ear wire and the nickel anode residues; Step b. Nickel anode scrap screening: The crushed nickel anode scrap is graded and screened, and the copper ear wire is used as the screened material, and the anode mud is used as the screened material to separate from the nickel anode scrap block, so as to reduce the content of Cu and sulfate in the nickel sulfate solution. The anode scrap block is discharged as the screened material, and the nickel anode scrap with a particle size of ≤10mm is sent to slurry preparation, and the nickel anode scrap with a particle size of >10mm is returned to the crushing for secondary treatment, the copper ear wire is recovered as the copper raw material, and the anode mud is sent for washing; among which, the anode mud removal rate is 90.9%, and the copper ear wire separation rate is 95.4%; Step c. Slurry preparation: nickel anode scrap blocks with a particle size of ≤10 mm are fed into a rod mill for rod grinding. The rod grinding time is controlled at 30 min to produce nickel anode scrap particles with a particle size of ≤5 mm. The slurry is then finely ground in a ball mill. The slurry concentration is controlled at 75%, the fine grinding time is controlled at 30 min, the slurry pH value is 6, and the nickel anode scrap particle size after fine grinding is ≤-280 mesh. The slurry after fine grinding is separated by a spiral slurry separator, and the nickel anode scrap particles with a particle size of >-280 mesh are returned to the fine mill for further processing; Step d. Slurry acidification: The prepared slurry is slurried by adding iron removal tailings washing liquid and anode mud washing liquid at a slurrying liquid-solid mass ratio of 1:6 for slurrying. The slurrying time is 0.5h. After adding sulfuric acid, the acid content of the slurry reaches 28.2g / l and the Cu content reaches 5.9g / l; Step e. Normal pressure leaching: compressed air flow rate is 100Nm 3 / h, reaction time is 8h, reaction temperature is 75~83℃, and end point pH value is 2.77; the composition of atmospheric pressure leaching solution is: Ni 69.14g / l, Cu 4.15g / l, Fe 4.38g / l, Co0.33g / l; Step f. Pressurized oxygen leaching: After atmospheric pressure leaching, the slurry enters the autoclave for further reaction. The compressed air flow rate is 800Nm 3 / h, the vapor phase temperature is 160-165℃, the kettle pressure is 1.5MPa, the reaction time is 8h, the end point pH is 2.8, and nickel is leached as much as possible, iron is precipitated in the form of hematite, and most of the Cu 2+ Under the inhibition of nitrogen in compressed air, it is not leached and enters and exits the iron removal slag in the form of CuS. After pressurized oxygen leaching, the slurry is separated by liquid and solid to obtain a relatively pure nickel sulfate solution. At the same time, the iron removal tailings by-product is produced; the composition of the pressurized leaching solution is: Ni 133.95g / l, Cu 1g / l, Fe3g / l, Co1.37g / l; Step g. Countercurrent washing: The iron removal tailings produced by pressurized oxygen leaching are continuously countercurrent washed, the mass ratio of washing water to iron removal tailings is 1:11, the washing temperature is 29°C, the washing time is 2h, the iron removal slag contains 0.99% Ni and 55.1% Fe, and is sold as iron raw material. The recycled iron removal tailings washing liquid contains 46.4g / l Ni, and the returned ore pulp is acidified to utilize the residual acid and recover nickel; Step h. Anode mud washing: the anode mud screened from the nickel anode residues is slurried in a slurry liquid-solid mass ratio of 1:3, and the slurry liquid-solid mass ratio is controlled to perform multi-stage countercurrent slurry washing. The washing time is 2 hours, and the washing temperature is 29°C. The washed nickel anode residue fine particles are returned to the ore pulp for use. The recycled anode mud washing liquid contains 45.8g / l Ni. The returned ore pulp is acidified to utilize the residual acid and recover nickel. The washed anode mud contains 0.5% Ni and is sent to hot melt sulfur extraction to prepare elemental sulfur and enrich precious metals.
Claims
1. A method for preparing nickel sulfate solution using nickel residual anode, characterized in that: The steps include: Step a, crushing nickel anode scraps: crushing the nickel anode scraps produced by nickel electrolysis in two stages, and at the same time, removing the anode mud attached to the surface of the nickel anode scraps to separate the copper ear wires from the nickel anode scraps; Step b, nickel anode butt screening: The nickel anode butt is crushed into nickel anode butt blocks, and the copper ear wire, anode mud and nickel anode butt are separated and graded and screened. The copper ear wire is used as the screen over material, and the anode mud is used as the screen under material to separate from the nickel anode butt blocks, so as to reduce the Cu in the nickel sulfate solution. 2+ The nickel anode scraps are discharged as the sieve, the nickel anode scraps with a particle size of more than 25mm are returned for crushing and secondary treatment, the copper ear wire is recovered as copper raw material, and the anode mud is sent for washing; Step c, slurry preparation: nickel residual anode blocks with a particle size of ≤25 mm are fed into a rod mill for rod grinding, and the nickel residual anode particles produced by the rod grinding are finely ground in a ball mill. After fine grinding, the slurry is equipped with a spiral slurry separator. Under the action of the spiral slurry separator, components with larger particle sizes move downward in the axial direction and outward in the radial direction at the same time under the action of the cyclone field, and move downward along the wall of the device when reaching the cone section of the spiral slurry separator, and are discharged from the bottom flow port, and return to the ball mill for further fine grinding, and components with smaller particle sizes of the slurry move toward the central axis, and form an upwardly moving inner vortex at the center of the axis, and are then discharged from the overflow port and sent to the slurry for acidification; Step d, slurry acidification: after adding iron removal tailings washing liquid and anode mud washing liquid to the prepared slurry according to the slurry liquid-to-solid mass ratio, add an appropriate amount of sulfuric acid; Step e, atmospheric pressure leaching: introducing an appropriate amount of compressed air or industrial pure oxygen, controlling the reaction time and temperature, leaching out the alloy phases and oxides of nickel, cobalt, copper, etc. contained in the nickel anode scrap as much as possible, converting Ni3S2 into NiS, dissolving and leaching out all the copper ear wire fragments entrained in the nickel anode scrap, and ensuring that Cu in the leaching system is 2+ and Cu + Cycle balance; Step f, pressurized oxygen leaching: After atmospheric pressure leaching, the ore pulp enters the autoclave for further reaction, and sufficient oxidant is added. The reaction pressure, temperature and time are controlled to leach out nickel as much as possible, precipitate iron in the form of hematite, and precipitate most of Cu 2+ Under the inhibition of nitrogen in compressed air, it is not leached and enters and exits the iron removal slag in the form of CuS. After pressurized oxygen leaching, the slurry is separated by liquid and solid to obtain a relatively pure nickel sulfate solution. At the same time, the iron removal tailings by-product is produced; Step g, countercurrent washing: the iron removal tailings produced by pressurized oxygen leaching are continuously countercurrent washed, and the mass ratio of leaching water to the iron removal tailings is controlled to obtain iron removal slag with low Ni content and high Fe content. The iron removal slag is sold and processed as an iron raw material. After the iron removal tailing washing liquid is enriched with Ni, the returned ore pulp is acidified to utilize the residual acid and recover nickel; Step h, anode mud washing: the anode mud screened out from the nickel residual anode is subjected to multi-stage slurry washing according to the slurry liquid-to-solid mass ratio, and the washed nickel residual anode fine particles are prepared for return ore slurry. After the anode mud washing liquid is Ni enriched, the return ore slurry is acidified to utilize the residual acid and recover nickel. The washed anode mud is sent to hot melt sulfur extraction to prepare elemental sulfur and enrich precious metals.
2. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: The particle size of the nickel residual electrodes after crushing in step a is ≤10 mm.
3. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In the step b, the anode mud removal rate is ≮90%, and the copper ear wire separation rate is ≮95%.
4. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In the step c, the rod mill grinding time is controlled at 20 to 40 minutes, the particle size of the output nickel residual anode particles is ≤5 mm, the mass percentage concentration of the ore pulp finely ground by the ball mill is 75 to 85%, the fine grinding time is 20 to 30 minutes, the pH value of the ore pulp is between 6 and 7, and the particle size of the nickel residual anode after fine grinding is ≤-280 mesh ≥90%.
5. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In the step d, the slurry liquid-to-solid mass ratio is 1:6-8, the slurrying time is 0.5-1h, the slurry contains 15-40g / l of acid, and the pre-slurry liquid contains 3-8g / l of Cu.
6. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In step e, the reaction temperature is 70-90°C, and the amount of compressed air introduced is 50-120 Nm 3 / h, the reaction time is 6 to 10 hours, and the pH value of the slurry at the end point of normal pressure leaching is 2.0 to 3.
0.
7. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In step f, the oxidant is compressed air, and the amount of compressed air introduced is 500-2000 Nm 3 / h, the vapor phase temperature is 155-165°C, the autoclave pressure is 1.4-1.6MPa, the reaction time is 6-8h, and the slurry pH value at the end point of pressure leaching is 1.5-2.
5.
8. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In the step g, the mass ratio of rinsing water to iron removal tailings is 1:10-12, the washing temperature is 20-35°C, the washing time is 1-2h, the iron removal slag contains Ni<1% and Fe≥53%, and the recycled iron removal tailings washing liquid has Ni≥40g / l.
9. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In the step h, the liquid-to-solid mass ratio of the slurry washing is 1:3-4, the washing temperature is 20-35°C, the washing time is 1-2h, and the anode mud washing liquid Ni is recycled. 2+ ≥40g / l, the Ni content of anode mud after washing is <0.5%.
10. The method for preparing nickel sulfate solution using nickel residual anode according to claim 1, characterized in that: In step f, the nickel sulfate solution Ni 2+ ≥120g / l, Cu 2+ ≤1g / l, Fe 2+ ≤3g / l.