Method for preparing and purifying nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw material

Abstract

The present application belongs to the field of hydrometallurgy or chemical technology, and particularly relates to a method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw material, which comprises the steps of reduction leaching, iron and aluminum removal and precipitation, concentration, aging, desilication and flocculation desilication. 2+ The present application uses reduction leaching instead of direct leaching with sulfuric acid, greatly improves the direct recovery rate of nickel, cobalt and scandium, uses nickel carbonate instead of part of sodium carbonate to improve the Ni + concentration and reduce the Na concentration; the flocculation desilication of the nickel-cobalt solution after the first iron and aluminum removal can solve the problem of intermediate phase in the extraction process. The method of removing silicon with polyferric sulfate is easy to operate, stable in index and low in price, and does not bring new impurities to the system; the concentration, aging and desilication of the iron and aluminum residue solve the problem of high silicon content in the scandium-containing solution and prevent the interference of silicon in the scandium extraction and purification process. The method proposed in the present application has a simple process, less residue and can save resources and reduce processing cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of hydrometallurgy or chemical technology, and particularly relates to a method for preparing purified nickel-cobalt solution and separating nickel from scandium from nickel-cobalt hydroxide raw materials. BACKGROUND

[0002] Laterite nickel ore has become the main ore resource of nickel raw materials due to its advantages of rich reserves, easy mining and low mining cost. Nickel-cobalt hydroxide produced by transformation of laterite nickel ore gradually becomes the main raw material for producing ternary precursor products for batteries (such as positive electrode composite materials) because of its lower price than that of nickel raw materials produced by sulfide nickel ore. The nickel-cobalt hydroxide contains impurities such as iron, aluminum, manganese, magnesium and silicon in addition to nickel and cobalt. The current treatment method is to slurry and dissolve the nickel-cobalt hydroxide material, remove impurities by extraction and purification, and then reuse. However, in order to remove iron and aluminum, the pH value of the solution in the impurity removal process is adjusted to 5.0-5.2 or higher, which causes a large amount of nickel to precipitate, reduces the recovery rate of nickel, and does not perform recovery treatment. Moreover, the soluble silicon content in laterite nickel ore is high, and when the leaching-extraction process is used, the silicon dioxide in it is dissolved in the form of silicic acid. In the extraction of leaching solution, the silicic acid in the solution forms a large amount of interphase dirt, which causes difficulty in extraction and back-extraction phase separation, resulting in phase entrainment, extraction production chaos, and even production stoppage in severe cases. The removal of silicon is the most difficult point in the process of wet leaching.

[0003] A variety of treatment processes have been proposed in the prior art. Patent No. CN112779419A discloses a method for removing iron, aluminum and silicon from nickel-cobalt-manganese-copper solution at normal pressure. The present application comprises the following steps: taking crude nickel-cobalt-manganese-copper raw material, mixing and slurring with water, then adding acid and reducing agent for leaching, with the leaching endpoint pH≤2.5, and controlling the appropriate Fe 2+ content; the above leaching slurry is separated by thickening, and the supernatant and the precipitant are added to the iron, aluminum and silicon removal solution containing nickel-cobalt-manganese-copper at a temperature of 70-100℃ and kept warm, the precipitant is crude nickel-cobalt-manganese-copper raw material with a solid content of 1-50%, the pH of the iron, aluminum and silicon removal is 3.0-4.0; the above slurry is separated by solid-liquid separation, the filtrate is used as the extraction raw solution, the iron, aluminum and silicon removal residue and the leaching residue are configured into a slurry with a solid content of ≤50%, acid is added to adjust the pH to 2.0-3.5, a reducing agent is added to make Fe 2+ ≥0.1g / L, and the iron, aluminum and silicon removal residue and the filtrate are obtained by solid-liquid separation, and the filtrate is sent to the leaching section for raw material leaching. The present application does not need to use auxiliary materials, hazardous chemicals, or introduce other elements, but only removes iron, aluminum and silicon in the patent, without further processing of the iron, aluminum and silicon residue, and without desiliconization treatment of the filtrate.

[0004] Patent CN110551905A discloses a method for treating nickel-cobalt hydroxide, mainly involving aging and reduction leaching processes. It only describes methods for removing Si, Na, and COD, without addressing the removal of impurities such as aluminum and iron. Furthermore, the patent performs desiliconization at the upstream stage of the nickel-cobalt hydroxide treatment, resulting in a large material volume and viscous silica gel that is difficult to filter, making nickel-scandium separation impossible.

[0005] The patent with publication number CN 112359225A proposes a selective leaching process for crude cobalt hydroxide ore. It uses manganese dioxide for pre-oxidation treatment to avoid the repeated use of reducing and oxidizing agents. However, it adds sodium metabisulfite, which increases the COD content in the solution. The resulting solution is a crude solution with a high impurity content and cannot achieve the separation of nickel and scandium.

[0006] Therefore, the methods for preparing purified nickel-cobalt solutions and separating nickel and scandium from nickel-cobalt hydroxide still need further improvement. Summary of the Invention

[0007] To address the above problems, this invention proposes a method for preparing a purified nickel-cobalt solution from nickel-cobalt hydroxide raw materials and for separating nickel and scandium. The method includes the following steps:

[0008] Reduction leaching: The nickel-cobalt hydroxide raw material is made into a slurry, concentrated sulfuric acid is injected into the slurry, and after stirring, dilute sulfuric acid is added dropwise to adjust the pH. Stirring is continued and the first reducing agent is added to carry out the reaction. The first reaction solution is subjected to solid-liquid separation to obtain the first filtrate and the first filter residue.

[0009] Removal of iron and aluminum and precipitation of scandium: After adding a first neutralizing agent to the first filtrate to adjust the pH, oxidation is carried out. After oxidation, the second reaction liquid is separated into solid and liquid components to obtain a nickel-cobalt solution and iron-aluminum slag.

[0010] Concentration, aging, and desilication: The iron-aluminum slag is mixed with concentrated sulfuric acid and concentrated to a set liquid-solid ratio. Then, a second reducing agent is added for reduction, followed by solid-liquid separation to obtain silicon slag and a desilication scandium-containing solution.

[0011] Flocculation and silicon removal: Polyferric sulfate and a second neutralizing agent are added to the nickel-cobalt solution to react. After solid-liquid separation of the third reaction liquid, a purified nickel-cobalt solution and ferrosilicon slag are obtained. The purified nickel-cobalt solution is then extracted.

[0012] Furthermore, the liquid-to-solid ratio in the slurry is 6–10:1;

[0013] The stirring temperature is 60-90℃, and the stirring speed is 300-800 r / min;

[0014] The ratio of concentrated sulfuric acid and nickel-cobalt hydroxide added to the ore is 600-900 kg / t;

[0015] The concentration of the dilute sulfuric acid is 10-40 wt%.

[0016] Furthermore, the first reducing agent is one of H2O2, Na2S2O5, and SO2;

[0017] The coefficient for the first reducing agent is the amount of reducing agent used / the Mn content in the ore, which is 0.2 to 1 mol / mol.

[0018] Furthermore, the oxidant used in the oxidation is air or H2O2;

[0019] When the oxidant is air, the air flow rate is 50-200 mL / min;

[0020] When the oxidant is H2O2, the ratio of H2O2 to the first filtrate is 1.4:1000.

[0021] Furthermore, the iron-aluminum slag is mixed with concentrated sulfuric acid and then concentrated to a set liquid-to-solid ratio, specifically as follows:

[0022] First, concentrate the mixed solution to the first liquid-to-solid ratio, stir, and then add water to bring it to the set solid-to-liquid ratio.

[0023] The first liquid-to-solid ratio is 1.5-2.5:1, and the set liquid-to-solid ratio is 3-10:1.

[0024] Furthermore, the conditions for reacting the nickel-cobalt solution by adding ferric polysulfate and a second neutralizing agent are as follows:

[0025] The reaction temperature is 50-60℃, and the pH remains stable between 5.0 and 5.4 during the reaction.

[0026] The polyferric sulfate dosage coefficient PFS / SiO2 is 40-60 g / g.

[0027] Furthermore, the first neutralizing agent is NiCO3 and Na2CO3, and the pH adjustment by adding the first neutralizing agent to the first filtrate is specifically as follows:

[0028] First, add NiCO3 to the first filtrate to adjust the pH to 3.8-4.2, then add Na2CO3 to adjust the pH to 4.2-5.5;

[0029] The first neutralizing agent slurry has a solid content of 30-50%.

[0030] Furthermore, the second neutralizing agent is a Na2CO3 solution, which is used to maintain the pH of the third reaction solution stable between 5.0 and 5.4.

[0031] Furthermore, the second reducing agent is one of H2O2, Na2S2O5, and SO2;

[0032] The coefficient for the second reducing agent is the amount of reducing agent used / the Mn content in the ore, which is 0.5 to 1.5 mol / mol.

[0033] Furthermore, the method also includes:

[0034] Acid leaching and precipitation treatment: The ferrosilicon slag is subjected to acid leaching and precipitation treatment to obtain silicon slag and second filtrate; the second filtrate is returned to the concentration, aging and desiliconization step for treatment, and the silicon slag is waste residue and is treated separately.

[0035] Furthermore, the acid leaching conditions are as follows: liquid-to-solid ratio of 6-10:1, reaction temperature of 60-80℃, concentrated sulfuric acid addition of 400-600 kg / t dry ore, and reaction time of 2 hours;

[0036] The precipitation conditions are as follows: pH adjusted to 4.5-5.2 with Na2CO3, reaction time 3-4 h, and reaction temperature 50-70℃.

[0037] The beneficial effects of this invention are:

[0038] This invention utilizes reductive leaching instead of direct sulfuric acid leaching, which significantly improves the direct recovery rate of nickel, cobalt, and scandium.

[0039] Replacing some sodium carbonate with nickel carbonate can improve Ni 2+ Concentration and reduction of Na + Concentration. Because nickel carbonate dissolves slowly at high pH and requires a long equilibrium time, resulting in high Ni content and large slag volume in the slag, nickel carbonate is used to adjust the pH to low, and sodium carbonate is used to adjust the pH to high.

[0040] Flocculation and desiliconization of the nickel-cobalt solution after primary iron and aluminum removal can reduce the silicon content entering the extraction process and solve the problem of intermediate phases during extraction. The polyferric sulfate desiliconization method is easy to operate, provides stable performance, is inexpensive, and does not introduce new impurities into the system.

[0041] Concentration, aging, and silicon removal of iron-aluminum slag solved the problem of excessive silicon content in scandium-containing solutions and prevented silicon interference during scandium extraction and purification.

[0042] The method proposed in this invention has a simple process, produces less residue, saves resources, and reduces processing costs.

[0043] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 A flowchart of the method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials proposed in this invention is shown;

[0046] Figure 2 A detailed flowchart of the method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials proposed in the embodiments of the present invention is shown. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] This invention proposes a method for preparing a purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials. The method involves leaching nickel and cobalt from the nickel-cobalt hydroxide using sulfuric acid reduction, followed by neutralization of the leached slurry to a specific pH level using a neutralizing agent. This causes iron and aluminum to precipitate as iron-aluminum slag. Filtration yields a nickel-cobalt solution and the iron-aluminum slag, thus separating nickel and cobalt from iron and aluminum. The iron-aluminum slag is then concentrated and matured to obtain a desilication-containing scandium solution and silicon slag. The nickel-cobalt solution undergoes flocculation to remove silicon, followed by filtration to obtain a purified nickel-cobalt solution and ferrosilicon slag. The ferrosilicon slag is then subjected to acid leaching and precipitation again, yielding a secondary filter residue and a second filtrate. The second filtrate is returned to the concentration, maturation, and desilication process. The purified nickel-cobalt solution is then extracted. Due to the high purity of the purified nickel-cobalt solution and the ability to separate nickel and scandium, the byproduct scandium can be recovered.

[0049] The specific steps are as follows: Figure 1 As shown:

[0050] Reduction leaching: The nickel-cobalt hydroxide raw material is made into a slurry, concentrated sulfuric acid is injected into the slurry, and the mixture is stirred at 300-800 r / min at 60-90℃. After stirring, 10-40 wt% dilute sulfuric acid is added dropwise to adjust the pH, and stirring is continued. The first reducing agent is added to carry out the reaction. The first reaction solution is subjected to solid-liquid separation to obtain the first filtrate and the first filter residue.

[0051] The ratio of concentrated sulfuric acid to nickel-cobalt hydroxide in the feedstock is 600-900 kg / t, meaning that 600-900 kg of concentrated sulfuric acid is added to every 1 t of nickel-cobalt hydroxide.

[0052] The liquid-to-solid ratio in the slurry is 6-10:1, which is the ratio of nickel-cobalt hydroxide raw material to added liquid (water + acid); the first reducing agent is one of H2O2, Na2S2O5, and SO2, and the amount of reducing agent / Mn content in the ore is 0.2-1 mol / mol, that is, 0.2-1 mol of reducing agent is added for every 1 mol of Mn in the nickel-cobalt hydroxide raw material.

[0053] Removal of iron and aluminum and precipitation of scandium: After adding a first neutralizing agent to the first filtrate to adjust the pH, oxidation is carried out. After oxidation, the second reaction liquid is separated into solid and liquid components to obtain a nickel-cobalt solution and iron-aluminum slag.

[0054] The first neutralizing agent is NiCO3 and Na2CO3. The specific steps for adjusting the pH by adding the first neutralizing agent to the first filtrate are as follows:

[0055] First, add NiCO3 to the first filtrate to adjust the pH to 3.8-4.2, then add Na2CO3 to adjust the pH to 4.2-5.5;

[0056] The first neutralizing agent slurry has a solid content (i.e., the solid content of the first neutralizing agent slurry) of 30-50%;

[0057] The oxidant is air or H2O2; when the oxidant is air, the air flow rate is 50-200 mL / min.

[0058] When the oxidant is H2O2, the ratio of H2O2 to the first filtrate is 1.4:1000.

[0059] Concentration, aging, and desilication: The iron-aluminum slag is mixed with concentrated sulfuric acid and concentrated to a first liquid-solid ratio of 1.5-2.5:1. After stirring, water is added to the set liquid-solid ratio of 3-10:1. Then, a second reducing agent is added for reduction and solid-liquid separation is performed to obtain silicon slag and a desilication scandium-containing solution. Scandium in the desilication scandium-containing solution can be further recovered.

[0060] The second reducing agent is one of H2O2, Na2S2O5, and SO2;

[0061] The amount of the second reducing agent is calculated based on the Mn content in the iron-aluminum slag, and the coefficient for the second reducing agent is the amount of reducing agent / Mn content in the ore, which is 0.5 to 1.5 mol / mol.

[0062] Flocculation and silicon removal: Polyferric sulfate (PFS) and a second neutralizing agent are added to the nickel-cobalt solution to react at a temperature of 50-60°C. During the reaction, the pH is kept stable between 5.0 and 5.4 to obtain a third reaction solution. After solid-liquid separation of the third reaction solution, purified nickel-cobalt solution and ferrosilicon slag are obtained. The purified nickel-cobalt solution is then extracted.

[0063] The amount of polyferric sulfate used is calculated based on the SiO2 content in the nickel-cobalt solution, and the polyferric sulfate dosage coefficient PFS / SiO2 is 40-60 g / g.

[0064] The second neutralizing agent is a Na2CO3 solution, which is used to maintain the pH of the third reaction solution between 5.0 and 5.4.

[0065] Acid leaching and precipitation treatment: The ferrosilicon slag is subjected to acid leaching and precipitation treatment to obtain silicon slag and a second filtrate; the second filtrate is then subjected to a return concentration, ripening, and desilication step, while the silicon slag is treated separately as waste residue. The acid leaching conditions are: liquid-to-solid ratio of 6-10:1, reaction temperature of 60-80℃, concentrated sulfuric acid addition of 400-600 kg / t dry ore, and reaction time of 2 hours; the precipitation conditions are: pH adjusted to 4.5-5.2 with Na2CO3, reaction time of 3-4 hours, and reaction temperature of 50-70℃.

[0066] It should be noted that there is no strict order between the two steps of concentration and ripening desilication and flocculation desilication, and they can be performed simultaneously.

[0067] The following describes specific embodiments and Figure 2 The above methods and reaction conditions for each step are described in detail. The main steps include reduction leaching, removal of iron and aluminum and scandium precipitation, concentration and ripening for desilication, flocculation for desilication, and acid leaching and precipitation.

[0068] Example 1

[0069] Reduction leaching: The nickel-cobalt hydroxide raw material is prepared into a slurry. Concentrated sulfuric acid is injected into the slurry to dissolve it. The acid-to-ore ratio is 800 kg / t (800 kg of concentrated sulfuric acid is added to every 1 t of nickel-cobalt hydroxide). The mixture is stirred for 0.5 h at a reaction temperature of 80 °C. 30 wt.% dilute sulfuric acid is added dropwise to adjust the pH to 1.5, and stirring continues for another 1.5 h. The first reducing agent, H₂O₂, is added, and the reaction is continued for 0.5 h. Solid-liquid separation is then performed to obtain the first filtrate and the first filter residue.

[0070] Removal of iron and aluminum and precipitation of scandium: NiCO3 was added to the first filtrate to adjust the pH to 4.0, and Na2CO3 to adjust the pH to 5.2. The reaction temperature was 80℃, the oxidant was air, and the reaction was carried out for 4 hours. After solid-liquid separation, nickel-cobalt solution and iron-aluminum slag were obtained. NiCO3 and Na2CO3 together served as the first neutralizing agent.

[0071] Concentration, aging, and desilication: The iron-aluminum slag is mixed with concentrated sulfuric acid at an acid-to-ore ratio of 800 kg / t, concentrated at 90°C, and concentrated to a liquid-to-solid ratio of 2:1. After concentration, the mixture is stirred for 2 hours. Water is then added to bring the liquid-to-solid ratio to 8:1, and reducing agent H₂O₂ is added. The reduction time is 0.5 hours. Solid-liquid separation is then performed to obtain silicon slag and a desilication-containing scandium solution.

[0072] Flocculation and silicon removal: Polyferric sulfate is added to the nickel-cobalt solution, with a polyferric sulfate dosage coefficient (PFS / SiO2) of 50 g / g. The reaction temperature is 60°C. Simultaneously, a second neutralizing agent, sodium carbonate solution, is added to maintain a stable pH of 5.2 during the experiment. The stirring speed is 500 r / min. Solid-liquid separation is then performed to obtain a purified nickel-cobalt solution and ferrosilicon slag. The purified nickel-cobalt solution is then sent to the extraction process.

[0073] Acid leaching and precipitation: The ferrosilicon slag obtained from the flocculation and desiliconization process is subjected to acid leaching and precipitation again to separate Ni, Co, Mn and Fe, resulting in silicon slag and a second filtrate. The second filtrate is returned to the concentration, aging and desiliconization process, while the silicon slag is treated separately as waste.

[0074] The acid leaching conditions were: a liquid-to-solid ratio of 8:1, a reaction temperature of 70℃, and a concentrated sulfuric acid addition of 500 kg / t. 干矿料 The reaction was carried out for 2 hours. Precipitation conditions: pH was adjusted to 5.2 with Na2CO3, reaction time was 4 hours, and reaction temperature was 70℃.

[0075] The results of the reduction leaching step and the iron and aluminum removal scandium precipitation step are shown in Table 1:

[0076] Table 1. Reduction leaching steps and results of iron and aluminum removal and scandium precipitation.

[0077]

[0078] The results of the flocculation and desiliconization step are shown in Table 2:

[0079] Table 2 Results of the flocculation and silica removal process

[0080]

[0081] The results of the concentration, ripening, and desilication steps are shown in Table 3:

[0082] Table 3 Results of Concentration, Maturation, and Desilication Steps

[0083]

[0084] Example 2

[0085] Unlike the previous example, the acid-to-ore ratio in the reduction leaching step was 600 kg / t, while all other conditions remained unchanged. The leaching results for the reduction leaching steps to remove iron and aluminum and scandium precipitation are shown in Table 4.

[0086] Table 4. Reduction leaching steps and results of iron and aluminum removal and scandium precipitation.

[0087]

[0088] Example 3

[0089] Unlike the previous example, the acid-to-ore ratio in the reduction leaching step was 900 kg / t, while all other conditions remained unchanged. The results of the reduction leaching step for removing iron, aluminum, and scandium are shown in Table 5.

[0090] Table 5. Reduction leaching steps and results of iron and aluminum removal and scandium precipitation.

[0091]

[0092] Example 4

[0093] Unlike the previous example, in the steps of removing iron and aluminum and precipitating scandium, NiCO3 was added to the first filtrate to adjust the pH to 5.2, while the other conditions remained unchanged. The leaching results of removing iron and aluminum and precipitating scandium are shown in Table 6.

[0094] Table 6. Reduction leaching steps and results of iron and aluminum removal and scandium precipitation.

[0095]

[0096] Example 5

[0097] Unlike the previous example, in the concentration, aging, and desilication step, the liquid-to-solid ratio was concentrated to 2.5:1, while all other conditions remained unchanged. The leaching results of the concentration, aging, and desilication step are shown in Table 7.

[0098] Table 7. Leaching results of the concentration, ripening, and desilication steps.

[0099]

[0100] Example 6

[0101] Unlike Example 1, in the flocculation and desiliconization step, polyferric sulfate was added to the nickel-cobalt solution. The polyferric sulfate dosage coefficient (PFS / SiO2) was 40 g / g, and the other conditions remained unchanged. The leaching results of the flocculation and desiliconization step are shown in Table 8.

[0102] Table 8 Results of the flocculation and silica removal steps

[0103]

[0104] Comparative Example 1

[0105] Unlike Example 1, the acid-to-ore ratio in the reduction leaching step was 400 kg / t, while all other conditions remained unchanged. The results of iron and aluminum removal and scandium precipitation leaching are shown in Table 9.

[0106] Table 9. Reduction leaching steps and results of iron and aluminum removal and scandium precipitation.

[0107]

[0108] Comparative Example 2

[0109] Unlike Example 1, in the step of removing iron and aluminum and precipitating scandium, Na2CO3 was added to the first filtrate to adjust the pH to 5.2, and the other conditions remained unchanged. The results of the removal of iron and aluminum and precipitating scandium are shown in Table 10.

[0110] Table 10 Reduction leaching steps and results of iron and aluminum removal and scandium precipitation

[0111]

[0112] Comparative Example 3

[0113] Unlike Example 1, in the concentration, aging, and desilication step, the liquid-to-solid ratio was concentrated to 4:1, while all other conditions remained unchanged. The leaching results of the concentration, aging, and desilication step are shown in Table 11.

[0114] Table 11 Leaching results of the concentration, ripening, and desilication steps

[0115]

[0116] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a purified nickel-cobalt solution from a nickel-cobalt hydroxide raw material and for separating nickel and scandium, characterized in that, The method includes the following steps: Reduction leaching: The nickel-cobalt hydroxide raw material is made into a slurry, concentrated sulfuric acid is injected into the slurry, and after stirring, dilute sulfuric acid is added dropwise to adjust the pH. Stirring is continued and the first reducing agent is added to carry out the reaction. The first reaction solution is subjected to solid-liquid separation to obtain the first filtrate and the first filter residue. Removal of iron and aluminum and precipitation of scandium: After adding a first neutralizing agent to the first filtrate to adjust the pH, oxidation is carried out. After oxidation, the second reaction liquid is separated into solid and liquid components to obtain a nickel-cobalt solution and iron-aluminum slag. The first neutralizing agent is NiCO3 and Na2CO3. The oxidation process after adding the first neutralizing agent to the first filtrate to adjust the pH includes: first adding NiCO3 to the first filtrate to adjust the pH to 3.8-4.2, and then adding Na2CO3 to adjust the pH to 4.2-5.

5. Concentration, aging, and desilication: The iron-aluminum slag is mixed with concentrated sulfuric acid and concentrated to a set liquid-solid ratio. Then, a second reducing agent is added for reduction, followed by solid-liquid separation to obtain silicon slag and a desilication-containing scandium solution. Specifically, the process of concentrating the iron-aluminum slag with concentrated sulfuric acid to a set liquid-solid ratio involves first concentrating the mixed solution to a first liquid-solid ratio, stirring, and then adding water to reach the set solid-solid ratio. The first liquid-solid ratio is 1.5-2.5:1, and the set liquid-solid ratio is 3-10:

1. Flocculation and silicon removal: Polyferric sulfate and a second neutralizing agent are added to the nickel-cobalt solution to react. After solid-liquid separation of the third reaction liquid, a purified nickel-cobalt solution and ferrosilicon slag are obtained. The purified nickel-cobalt solution is then extracted. The polyferric sulfate dosage coefficient PFS / SiO2 is 40-60 g / g.

2. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1, characterized in that, The liquid-to-solid ratio in the slurry is 6-10:1; The stirring temperature is 60-90℃, and the stirring speed is 300-800 r / min; The ratio of concentrated sulfuric acid and nickel-cobalt hydroxide added to the ore is 600-900 kg / t; The concentration of the dilute sulfuric acid is 10-40 wt%.

3. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1 or 2, characterized in that, The first reducing agent is one of H2O2, Na2S2O5, and SO2; The coefficient for the first reducing agent is the amount of reducing agent used / the amount of Mn in the ore, which is 0.2~1 mol / mol.

4. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1, characterized in that, The oxidant used in the oxidation is air or H2O2; When the oxidant is air, the air flow rate is 50-200 mL / min; When the oxidant is H2O2, the ratio of H2O2 to the first filtrate is 1.4:1000.

5. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1, characterized in that, The conditions for reacting the nickel-cobalt solution by adding ferric polysulfate and a second neutralizing agent are as follows: The reaction temperature is 50-60℃, and the pH remains stable between 5.0 and 5.4 during the reaction.

6. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1, characterized in that, The second neutralizing agent is a Na2CO3 solution, which is used to maintain the pH of the third reaction solution between 5.0 and 5.

4.

7. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1, characterized in that, The second reducing agent is , , One of them; The coefficient for the second reducing agent is the amount of reducing agent used / the Mn content in the ore, which is 0.5~1.5 mol / mol.

8. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 1, characterized in that, The method further includes: Acid leaching and precipitation treatment: The ferrosilicon slag is subjected to acid leaching and precipitation treatment to obtain silicon slag and second filtrate; the second filtrate is returned to the concentration, aging and desiliconization step for treatment, and the silicon slag is waste residue and is treated separately.

9. The method for preparing purified nickel-cobalt solution and separating nickel and scandium from nickel-cobalt hydroxide raw materials according to claim 8, characterized in that, The acid leaching conditions are as follows: liquid-to-solid ratio of 6-10:1, reaction temperature of 60-80℃, and concentrated sulfuric acid added in the amount specified. The reaction lasted for 2 hours. The precipitation conditions are as follows: pH adjusted to 4.5-5.2 with Na2CO3, reaction time 3-4 h, and reaction temperature 50-70℃.

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