Wet treatment process for nickel laterite ore

Abstract

Provided in the present disclosure is a wet treatment process for nickel laterite ore. The wet treatment process comprises: step S1, subjecting nickel laterite ore to an acid leaching treatment with an inorganic acid, so as to obtain a leached ore slurry; step S2, sequentially performing liquid-solid separation and counter-current washing on the leached ore slurry, so as to obtain a washed slurry and a leaching residue; step S3, adding a first oxidant and a first neutralizer to the washed slurry for an iron-aluminum removal treatment, so as to obtain a solution from which iron and aluminum have been removed and an iron-aluminum residue; step S4, performing a nickel-cobalt precipitation treatment on the solution from which iron and aluminum have been removed, so as to obtain a precipitated slurry; step S5, continuously performing a thickening separation treatment on the precipitated slurry, so as to obtain an underflow and an overflow; and step S6, sequentially performing post-washing treatments on the underflow, so as to obtain a nickel-cobalt hydroxide product. The present disclosure provides a short-flow wet treatment process for nickel laterite ore, which reduces production costs and energy consumption, and also improves the recovery rate of nickel and cobalt, the overall recovery rate of scandium and the quality of the nickel-cobalt oxide product.

Description

Hydrometallurgical Processes for Laterite Nickel Ore

[0001] This disclosure claims priority to Chinese Patent Application No. 202510209443.X, filed on February 25, 2025, entitled “Wet Processing Technology for Laterite Nickel Ore”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to the field of hydrometallurgical technology for laterite nickel ore, and more specifically, to a hydrometallurgical process for laterite nickel ore. Background Technology

[0003] Currently, laterite nickel ore is the main raw material in the EV battery industry chain. High-pressure leaching is the mainstream process for producing nickel-cobalt intermediate products. The main process is: leaching—pre-neutralization—two-stage iron and aluminum removal—two-stage nickel and cobalt precipitation—tailings neutralization. This process is mature and widely used by companies. However, the inventors realized that the biggest problem with this process is:

[0004] (1) The process is lengthy, requiring two stages of iron and aluminum removal and two stages of nickel and cobalt precipitation. The purpose of the two stages of iron and aluminum removal is: in the first stage, the pH is controlled at a low level, generally 3.8, to reduce nickel and cobalt loss, and the iron and aluminum slag from the first stage is discharged from the system via an open circuit; in the second stage, the pH is controlled at 4.8 to precipitate the iron and aluminum completely, providing an iron- and aluminum-free solution for subsequent nickel and cobalt recovery. The nickel and cobalt content in the iron and aluminum slag from the second stage is high, and it is returned to the leaching pulp to neutralize residual acid for nickel and cobalt recovery. The purpose of the two stages of nickel and cobalt precipitation is: in the first stage, the pH is controlled at a low level as nickel-cobalt hydroxide (MHP) product, and in the second stage, the pH is controlled at a high level, so that all nickel and cobalt are precipitated and returned to the leaching pulp to neutralize residual acid for nickel and cobalt recovery.

[0005] (2) MHP products are of poor quality. The magnesium content in MHP is generally about 1% to 5%, and the manganese content is about 5% to 8%, which increases the complexity and cost of subsequent refining processes.

[0006] (3) Scandium is lost in iron and aluminum slag, resulting in a low overall recovery rate.

[0007] In view of this, this disclosure is hereby made. Summary of the Invention

[0008] In view of the above problems, the purpose of this disclosure is to provide a wet processing technology for laterite nickel ore to solve the problems of long process, poor quality of nickel-cobalt hydroxide product and low overall scandium recovery rate in the high-pressure leaching process of laterite nickel ore in the prior art.

[0009] To achieve the above objectives, according to one aspect of this disclosure, a wet processing technology for laterite nickel ore, including limonite-type and / or residual laterite nickel ore, is provided. The wet processing technology includes: step S1, acid leaching the laterite nickel ore with inorganic acid to obtain a leached slurry; step S2, sequentially performing liquid-solid separation and countercurrent washing on the leached slurry to obtain a washed slurry and leaching residue; step S3, adding a first oxidant and a first neutralizing agent to the washed slurry for iron and aluminum removal treatment to obtain an iron and aluminum removed solution and iron and aluminum slag; step S4, precipitating nickel and cobalt in the iron and aluminum removed solution to obtain a precipitated slurry; step S5, continuously thickening the precipitated slurry to obtain an underflow and an overflow; step S6, sequentially washing and treating the underflow to obtain a nickel and cobalt hydroxide product; wherein the iron and aluminum slag is returned to the acid leaching step.

[0010] One optional technical solution is that, in step S3 above, the temperature for iron and aluminum removal treatment is 25℃~100℃, the time for iron and aluminum removal treatment is 0.5h~8h; and / or the final pH value for iron and aluminum removal treatment is 3.8~5.5; and / or, the mass content of nickel in the iron and aluminum slag is 1%~8%, and the mass content of cobalt is 0.1%~0.9%.

[0011] One optional technical solution is that, in step S3 above, the first oxidant is selected from any one or more of the following: a mixture of oxygen and sulfur dioxide, oxygen, ozone, persulfate, hydrogen peroxide, nitrite, and perchlorate, and / or the amount of the first oxidant added is 1.0 to 10.0 times the stoichiometric ratio of ferrous iron in the slurry after washing.

[0012] One optional technical solution is that, in step S3 above, the first neutralizing agent is selected from any one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, calcium bicarbonate, limestone, magnesia powder, magnesite, dolomite, and marble.

[0013] One optional technical solution is that, in step S4 above, the temperature for nickel-cobalt precipitation treatment is 25℃~100℃, the time for nickel-cobalt precipitation treatment is 0.5h~8h; and / or the final pH value for nickel-cobalt precipitation treatment is 7.0~9.0.

[0014] One optional technical solution is that, in step S4 above, the process of precipitating nickel and cobalt includes: directly adding the precipitant to the solution after removing iron and aluminum to precipitate nickel and cobalt; or using a magnesium-containing solution to first generate active magnesium hydroxide with the precipitant, and then adding the active magnesium hydroxide to the solution after removing iron and aluminum to precipitate nickel and cobalt; and / or the precipitant is selected from any one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, and calcium bicarbonate.

[0015] One optional technical solution is that, in step S1 above, the acid leaching temperature is 90℃~280℃, the acid leaching time is 0.5h~8h; and / or the final acidity of the acid leaching is 0.1g / L~50g / L; and / or the acid leaching pressure is 1MPa~4MPa.

[0016] One optional technical solution is that, in step S1 above, the inorganic acid is selected from any one or more of sulfuric acid, hydrochloric acid, and nitric acid.

[0017] Among the optional technical solutions, in step S2 above, the liquid-solid separation method is thickener separation or filter press separation; and / or the countercurrent washing method is any one of multi-stage thickener series countercurrent washing, filter press on-machine countercurrent washing, and slurry countercurrent washing.

[0018] One optional technical solution is that, in step S6 above, the post-washing treatment process includes sequential acidic solution washing, alkaline solution washing, and nickel-cobalt solution washing.

[0019] One optional technical solution is that, in step S6 above, the amount of acidic solution used for acidic solution washing treatment is 0.01% to 100% of the solid weight of nickel-cobalt hydroxide product; and / or the mass concentration of the acidic solution is 0.01wt% to 5wt%, and the acidic solution is selected from any one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution, carbonic acid solution and organic acid solution; and / or the temperature of acidic solution washing treatment is 25℃ to 100℃, and the time of acidic solution washing treatment is 0.5h to 8h.

[0020] One optional technical solution is that, in step S6 above, the amount of alkaline solution used for alkaline solution washing treatment is 0.01% to 100% of the solid weight of nickel-cobalt hydroxide product; and / or the mass concentration of alkaline solution is 0.1wt% to 40wt%, and the alkaline solution is selected from one or more of sodium hydroxide solution, potassium hydroxide solution, ammonia water and carbonate solution; and / or the temperature of alkaline solution washing treatment is 25℃ to 100℃, and the time of alkaline solution washing treatment is 0.5h to 8h.

[0021] One optional technical solution is that, in step S6 above, the mass of the nickel-cobalt solution used for washing is 0.01% to 100% of the solid mass of the nickel-cobalt hydroxide product; and / or the mass concentration of nickel-cobalt in the nickel-cobalt solution is 0.1 g / L to 100 g / L, and the nickel-cobalt solution is selected from any one or more of the following: leaching solution, solution before iron and aluminum removal, solution after iron and aluminum removal, and self-prepared nickel-cobalt solution; and / or the temperature of the nickel-cobalt solution washing treatment is 25℃ to 100℃, and the washing time is 0.5 h to 8 h.

[0022] One optional technical solution is that the above-mentioned wet treatment process further includes: returning part of the overflow to the countercurrent washing step; neutralizing the remaining overflow with the leaching residue to obtain tailings slurry; the neutralization temperature is 25℃~100℃, and / or the neutralization time is 0.5h~8h; and / or the final pH value of the neutralization is 7.0~9.0.

[0023] One optional technical solution is to add a second oxidant and a second neutralizing agent during the above neutralization process. The second oxidant is selected from any one or more of the following: a mixture of oxygen and sulfur dioxide, oxygen, ozone, persulfate, hydrogen peroxide, nitrite, and perchlorate; and / or the second neutralizing agent is selected from any one or more of the following: sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, and calcium bicarbonate.

[0024] The core of this disclosure lies in providing a short-process hydrometallurgical treatment method for laterite nickel ore. Through acid leaching, liquid-solid separation, and countercurrent washing, a washed slurry and leaching residue are obtained. The washed slurry undergoes a primary iron-aluminum removal process to obtain a post-iron-aluminum solution and iron-aluminum slag. The post-iron-aluminum solution undergoes a primary nickel-cobalt precipitation and post-treatment step. The iron-aluminum slag is returned to the acid leaching process, thereby achieving efficient enrichment of nickel and cobalt and improving the quality of the nickel-cobalt hydroxide product. The advantages of this disclosure are that it shortens the complex process of traditional two-stage iron-aluminum removal and two-stage nickel-cobalt precipitation, reducing production costs and energy consumption, while improving the recovery rate of nickel and cobalt, the overall scandium recovery rate, and the quality of the nickel-cobalt oxide product.

[0025] To achieve the foregoing and related objectives, one or more aspects of this disclosure include features that will be described in detail below and specifically pointed out in the claims. The following description and accompanying drawings illustrate certain exemplary aspects of this disclosure. However, these aspects indicate only a few of the various ways in which the principles of this disclosure can be applied. Furthermore, this disclosure is intended to include all such aspects and their equivalents. Attached Figure Description

[0026] Other objects and results of this disclosure will become more apparent and readily understood upon reference to the following description taken in conjunction with the accompanying drawings and the claims, and with a more complete understanding of this disclosure. The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure. In the drawings:

[0027] Figure 1 shows a flowchart of a wet processing technology for laterite nickel ore according to Embodiment 1 of this disclosure.

[0028] In all the accompanying drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed Implementation

[0029] In the following description, numerous specific details are set forth for illustrative purposes and to provide a thorough understanding of one or more embodiments. However, it will be apparent that the embodiments and features described herein can be combined with each other without conflict; these embodiments can also be implemented without these specific details. In other instances, well-known structures and devices are shown in block diagram form for ease of description of one or more embodiments.

[0030] The specific embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0031] As described in the background section, the existing high-pressure leaching process for laterite nickel ore to precipitate nickel and cobalt suffers from problems such as long process flow, poor quality of nickel and cobalt hydroxide products, and low overall scandium recovery rate.

[0032] To address the aforementioned problems, this disclosure provides a hydrometallurgical process for laterite nickel ore, including limonite-type and / or residual laterite nickel ore. The hydrometallurgical process includes: Step S1, acid leaching the laterite nickel ore with inorganic acid to obtain a leached slurry; Step S2, sequentially performing liquid-solid separation and countercurrent washing on the leached slurry to obtain a washed slurry and leaching residue; Step S3, adding a first oxidant and a first neutralizing agent to the washed slurry for iron and aluminum removal treatment to obtain an iron and aluminum removed solution and iron and aluminum slag; Step S4, precipitating nickel and cobalt in the iron and aluminum removed solution to obtain a precipitated slurry; Step S5, continuously thickening the precipitated slurry to obtain an underflow and an overflow; Step S6, sequentially washing and treating the underflow to obtain a nickel and cobalt hydroxide product; wherein the iron and aluminum slag is returned to the acid leaching step.

[0033] The core of this disclosure lies in providing a short-process hydrometallurgical treatment method for laterite nickel ore. Through acid leaching, liquid-solid separation, and countercurrent washing, a washed slurry and leaching residue are obtained. The washed slurry undergoes a primary iron-aluminum removal process to obtain a post-iron-aluminum solution and iron-aluminum slag. The post-iron-aluminum solution undergoes a primary nickel-cobalt precipitation and post-treatment step. The iron-aluminum slag is returned to the acid leaching process, thereby achieving efficient enrichment of nickel and cobalt and improving the quality of the nickel-cobalt hydroxide product. The advantages of this disclosure are that it shortens the complex process of traditional two-stage iron-aluminum removal and two-stage nickel-cobalt precipitation, reducing production costs and energy consumption, while improving the recovery rate of nickel and cobalt, the overall scandium recovery rate, and the quality of the nickel-cobalt oxide product.

[0034] In addition, iron-aluminum slag can be mixed with laterite nickel ore and then put into an autoclave for acid leaching treatment, or it can be put into an autoclave alone. After the iron-aluminum slag dissolves in the autoclave, nickel, cobalt, and scandium enter the solution, and iron and aluminum respectively form aluminum sulfate and hematite precipitates into the slag.

[0035] In some embodiments of this disclosure, in step S3 above, the temperature for iron and aluminum removal treatment is 25°C to 100°C, the treatment time is 0.5h to 8h, and / or the final pH value of the iron and aluminum removal treatment is 3.8 to 5.5; and / or the mass content of nickel in the iron and aluminum slag is 1% to 8%, and the mass content of cobalt is 0.1% to 0.9%.

[0036] Although this disclosure involves only one step of iron and aluminum removal, the control of conditions such as temperature and time in the iron and aluminum removal process promotes the chemical reaction. The specific endpoint pH range of the iron and aluminum removal process maximizes the complete precipitation of iron and aluminum and minimizes the dissolution of nickel and cobalt, avoiding unnecessary metal loss in subsequent processing and reducing the impact on the quality of the nickel-cobalt hydroxide product. Furthermore, to further improve the overall efficiency and effectiveness of the iron and aluminum removal process, the preferred temperatures are 40℃ to 90℃, the preferred treatment time is 4h to 6h, and the preferred endpoint pH value is 4.5 to 5.5. These optimized conditions help to minimize the nickel and cobalt content in the iron-aluminum slag. For example, the conditions in this disclosure ensure that the nickel content in the iron-aluminum slag is 1% to 6% and the cobalt content is 0.1% to 0.8%, thereby minimizing the loss of nickel and cobalt in the one-step iron and aluminum removal process. Furthermore, the temperature for iron and aluminum removal treatment can be 25℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, or any value within the range of 25℃ to 100℃, which will not be elaborated here; the treatment time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h, or any value within the range of 0.5h to 8h, which will not be elaborated here; the final pH value of the iron and aluminum removal treatment can be 3.8, 4.0, 4.2, 4.5, 5.0, 5.2, or 5.5, or any value within the range of 3.8 to 5.5, which will not be elaborated here.

[0037] In some embodiments of this disclosure, in step S3 above, the first oxidant is selected from any one or more of a mixture of oxygen and sulfur dioxide, oxygen, ozone, persulfate, hydrogen peroxide, nitrite, and perchlorate, and / or the amount of the first oxidant added is 1.0 to 10.0 times the stoichiometric ratio of ferrous iron in the slurry after washing.

[0038] The selection and dosage of the first oxidant (1.0 to 10.0 times the stoichiometric ratio, preferably 5.0 to 10.0 times the stoichiometric ratio) ensures that ferrous iron is oxidized to ferric iron, thereby promoting the reaction of ferric iron with the first neutralizing agent to form a precipitate. An excess of the first oxidant ensures complete oxidation of ferrous iron, preventing contamination or quality degradation of nickel-cobalt oxide products in subsequent processes. Furthermore, this disclosure preferentially uses a wide variety of widely available oxidants, which helps adapt to different operating conditions and cost control, providing greater flexibility for the iron and aluminum removal process. In addition, the dosage of the first oxidant can be 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, or 10.0 times the stoichiometric ratio of ferrous iron in the washed slurry, or any value within the range of 1.0 to 10.0 times, which will not be elaborated further here.

[0039] In some embodiments of this disclosure, in step S3 above, the first neutralizing agent is selected from any one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, calcium bicarbonate, limestone, magnesia powder, magnesite, dolomite, and marble.

[0040] The diverse selection of primary neutralizing agents allows for the effective precipitation of iron and aluminum under different pH and temperature conditions, while minimizing the impact on nickel and cobalt. Furthermore, different primary neutralizing agents can be adapted to different leaching solution compositions and reaction environments, thereby helping to improve the recovery rates of metals such as nickel, cobalt, and scandium, and reducing reagent consumption.

[0041] In some embodiments of this disclosure, in step S4 above, the temperature for nickel-cobalt precipitation treatment is 25°C to 100°C, the time for nickel-cobalt precipitation treatment is 0.5h to 8h, and / or the final pH value for nickel-cobalt precipitation treatment is 7.0 to 9.0.

[0042] The optimized conditions for nickel-cobalt precipitation described above facilitate the complete precipitation of nickel and cobalt while minimizing the co-precipitation of impurities such as magnesium and manganese, thereby improving the purity and quality of the nickel-cobalt hydroxide product. Proper control of the temperature and time during the nickel-cobalt precipitation process enhances precipitation efficiency, while a specific endpoint pH value helps to more accurately separate nickel and cobalt from other impurities, thus reducing the complexity and cost of subsequent refining processes. Furthermore, the preferred temperature for nickel-cobalt precipitation is 40–90°C, and the preferred precipitation time is 4–6 hours. Furthermore, the temperature for nickel-cobalt precipitation treatment can be 25℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, or any value within the range of 25℃ to 100℃, which will not be elaborated here; the precipitation time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h, or any value within the range of 0.5h to 8h, which will not be elaborated here; the final pH value for nickel-cobalt precipitation treatment can be 7.0, 7.5, 8.0, 8.5, or 9.0, or any value within the range of 7.0 to 9.0, which will not be elaborated here.

[0043] In some embodiments of this disclosure, step S4 above, the process of precipitating nickel and cobalt includes: directly adding the precipitant to the solution after removing iron and aluminum to precipitate nickel and cobalt; or using a magnesium-containing solution to first generate active magnesium hydroxide with the precipitant, and then adding the active magnesium hydroxide to the solution after removing iron and aluminum to precipitate nickel and cobalt; and / or the precipitant is selected from any one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, and calcium bicarbonate.

[0044] Two methods for precipitating nickel and cobalt (direct precipitation and activated magnesium hydroxide precipitation) improve the flexibility and efficiency of the nickel and cobalt precipitation process. The method of directly adding a precipitant is simpler and more direct, and is more suitable for situations with high nickel and cobalt concentrations and low impurity levels. While the method of pre-converting the precipitant into activated magnesium hydroxide precipitant adds a conversion step, activated magnesium hydroxide precipitation is more suitable for situations with low nickel and cobalt concentrations or high impurity levels, improving the selectivity and efficiency of precipitation and reducing nickel and cobalt loss. Preferably, the magnesium-containing solution is selected from any one or more of magnesium sulfate, magnesium nitrate, and magnesium chloride solutions, and the preferred mass concentration of the magnesium-containing solution is 0.1 g / L to 40 g / L. For example, the mass concentration of the magnesium-containing solution can be 0.1 g / L, 0.5 g / L, 1 g / L, 3 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, or 40 g / L, which will not be elaborated further here.

[0045] In some embodiments of this disclosure, in step S1 above, the acid leaching temperature is 90°C to 280°C, the acid leaching time is 0.5h to 8h, and / or the final acidity of the acid leaching is 0.1g / L to 50g / L; and / or the acid leaching pressure is 1MPa to 4MPa.

[0046] The optimized acid leaching conditions described above are beneficial for improving the leaching rate of nickel and cobalt, reducing acid consumption, and controlling the properties of the leaching residue. The temperature and time of the acid leaching treatment help improve leaching efficiency, while a reasonable endpoint acidity helps balance the needs of nickel and cobalt leaching with subsequent treatment. Acid leaching can be performed under atmospheric or high pressure, with high pressure leaching being preferred to improve nickel and cobalt leaching efficiency. The laterite nickel ore to be acid-leached can be limonite-type, residual laterite-type, or a mixture of ores in any proportion. Limonite-type and residual laterite-type laterite ore can be mixed and fed into the autoclave, or fed separately and sequentially. Furthermore, it is preferable that the acid-to-ore ratio during the acid leaching process is 200 kg / t ore to 400 kg / t ore, preferably 250 kg / t ore to 350 kg / t ore, thereby helping to balance acid leaching efficiency and minimize unnecessary acid waste. Furthermore, the preferred acid leaching temperature is 200℃~280℃, the acid leaching time is 1h~8h, the final acidity of the acid leaching is 5g / L~30g / L, and the acid leaching pressure is 3~4MPa. Furthermore, the acid leaching temperature can be 90℃, 100℃, 120℃, 140℃, 150℃, 170℃, 190℃, 200℃, 210℃, 220℃, 230℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, or 280℃, or any value within the range of 90℃ to 280℃, which will not be elaborated further here; the acid leaching time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h, or any value within the range of 0.5h to 8h, which will not be elaborated further here; the final acidity of the acid leaching treatment can be 0. The concentrations are 0.1 g / L, 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 8 g / L, 10 g / L, 12 g / L, 15 g / L, 20 g / L, 22 g / L, 25 g / L, 28 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, or 50 g / L. Of course, any value within the range of 0.1 g / L to 50 g / L is also possible, and will not be elaborated further here. The acid-ore ratio can be 200 kg / t ore, 220 kg / t ore, 250 kg / t ore, 255 kg / t ore, 280 kg / t ore, 300 kg / t ore, 320 kg / t ore, 350 kg / t ore, or 400 kg / t ore, and will not be elaborated further here.

[0047] In some embodiments of this disclosure, in step S1 above, the inorganic acid is selected from any one or more of sulfuric acid, hydrochloric acid, and nitric acid.

[0048] Acid leaching with sulfuric acid, hydrochloric acid, or nitric acid is used, as these inorganic acids have strong leaching capabilities, which is beneficial for the efficient extraction of nickel and cobalt from laterite nickel ore. Furthermore, sulfuric acid is preferred as the inorganic acid to further recover sulfate ions, achieving recycling and reducing production costs.

[0049] In some embodiments of this disclosure, in step S2 above, the liquid-solid separation method is thickener separation or filter press separation; and / or the countercurrent washing method is any one of multi-stage thickener series countercurrent washing, filter press on-machine countercurrent washing, and slurry countercurrent washing.

[0050] The selection of liquid-solid separation and countercurrent washing methods (thickener, filter press, multi-stage thickener series countercurrent washing, etc.) further improves the effect of countercurrent washing, reduces the acidity in the leaching residue, and recovers nickel and cobalt from the solution, thereby reducing resource waste.

[0051] In some embodiments of this disclosure, the post-washing treatment process in step S6 includes sequential acidic solution washing, alkaline solution washing, and nickel-cobalt solution washing.

[0052] The above post-washing conditions and the sequential acidic solution washing, alkaline solution washing, and nickel-cobalt-containing solution washing steps further optimize the purity of the nickel-cobalt hydroxide product. By gradually removing impurities, the market competitiveness of the products treated with acidic solution washing, alkaline solution washing, and nickel-cobalt-containing solution washing is improved.

[0053] In some embodiments of this disclosure, in step S6 above, the amount of acidic solution used for acidic solution washing treatment is 0.01% to 100% of the solid weight of the nickel-cobalt hydroxide product; and / or the mass concentration of the acidic solution is 0.01wt% to 5wt%, and the acidic solution is selected from any one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution, carbonic acid solution and organic acid solution; and / or the temperature of acidic solution washing treatment is 25°C to 100°C, and the time of acidic solution washing treatment is 0.5h to 8h.

[0054] The preferred acidic solution washing conditions and the selection of acidic solution dosage improve the removal rate of magnesium impurities in the nickel-cobalt hydroxide product. A reasonable acidic solution concentration and consumption can effectively dissolve magnesium impurities without over-dissolving nickel-cobalt, reducing the risk of quality degradation in the nickel-cobalt hydroxide product. Further, the preferred acidic solution dosage for the acidic solution washing treatment is 0.1% to 5% of the solid content of the nickel-cobalt hydroxide product, such as 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, or any value within the range of 0.1% to 5%, which will not be elaborated further here. To further improve the efficiency and effect of the acidic solution washing treatment, the preferred washing temperature is 50℃ to 80℃, and the washing time is 4 to 6 hours. Furthermore, the temperature for acidic solution washing can be 25℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, or any value within the range of 25℃ to 100℃, which will not be elaborated further here; the washing time for acidic solution can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, or 7h. The time interval can be 5h or 8h, or any point value within the range of 0.5h to 8h, which will not be elaborated here; the mass concentration of the acidic solution can be 0.01wt%, 0.02wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.3wt%, 0.5wt%, 1wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt%, or 5wt%, which will not be elaborated here.

[0055] In some embodiments of this disclosure, in step S6 above, the amount of alkaline solution used for alkaline solution washing treatment is 0.01% to 100% of the solid weight of the nickel-cobalt hydroxide product; and / or the mass concentration of the alkaline solution is 0.1wt% to 40wt%, and the alkaline solution is selected from one or more of sodium hydroxide solution, potassium hydroxide solution, ammonia water and carbonate solution; and / or the temperature of alkaline solution washing treatment is 25°C to 100°C, and the time of alkaline solution washing treatment is 0.5h to 8h.

[0056] The conditions of alkaline solution washing and the selection of alkaline substances improve the removal rate of manganese and sulfate ions, impurities, in nickel-cobalt hydroxide products. Specific alkaline conditions can promote the dissolution and separation of manganese without affecting the stability of nickel-cobalt, thus improving the purity of the nickel-cobalt hydroxide product. Further, it is preferred that the amount of alkaline solution used in the alkaline solution washing treatment is 0.1% to 5% of the solid weight of the nickel-cobalt hydroxide product, such as 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, or any value within the range of 0.1% to 5%, which will not be elaborated further here. To further improve the efficiency and effect of alkaline solution washing, it is preferred that the temperature of the alkaline solution washing treatment be 50℃ to 80℃, and the washing time be 4 to 6 hours. Furthermore, the temperature for alkaline solution washing can be 25℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, or any value within the range of 25℃ to 100℃, which will not be elaborated further here; the washing time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, etc. The time intervals can be h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h, or any point value within the range of 0.5h to 8h, which will not be elaborated here; the mass concentration of the alkaline solution can be 0.1wt%, 0.5wt%, 1wt%, 3wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, or 40wt%, which will not be elaborated here.

[0057] In some embodiments of this disclosure, in step S6 above, the mass of the nickel-cobalt solution used for washing treatment is 0.01% to 100% of the solid mass of the nickel-cobalt hydroxide product; and / or the mass concentration of nickel-cobalt in the nickel-cobalt solution is 0.1 g / L to 100 g / L, and the nickel-cobalt solution is selected from any one or more of leaching solution, solution before iron and aluminum removal, solution after iron and aluminum removal, and self-prepared nickel-cobalt solution; and / or the temperature of the nickel-cobalt solution washing treatment is 25°C to 100°C, and the washing time of the nickel-cobalt solution is 0.5 h to 8 h.

[0058] The selection of washing conditions and the nickel-cobalt content in the nickel-cobalt solution helps to compensate for the loss of nickel-cobalt during the washing process. Simultaneously, washing with the nickel-cobalt solution further removes impurities such as magnesium and manganese ions, ensuring the quality of the nickel-cobalt hydroxide product. Using the leaching solution, the solution before iron and aluminum removal, and the solution after iron and aluminum removal as sources of the nickel-cobalt solution helps to improve the recycling of these solutions and reduce nickel-cobalt loss, thereby increasing the overall recovery rate of nickel-cobalt. Furthermore, it is preferred that the amount of nickel-cobalt solution used in the washing treatment is 0.1% to 5% of the solid weight of the nickel-cobalt hydroxide product. For example, it can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, or any value within the range of 0.1% to 5%, which will not be elaborated further here. To further improve the efficiency and effectiveness of the nickel-cobalt solution washing treatment, the preferred washing temperature is 50℃~80℃, and the washing time is 4~6h. Furthermore, the washing temperature can be 25℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, or any value within the range of 25℃~100℃, which will not be elaborated further here. The washing time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h. Of course, it can also be any point value within the range of 0.5h to 8h, which will not be elaborated here; the mass concentration of nickel and cobalt in the nickel-cobalt-containing solution is 0.1g / L, 1g / L, 3g / L, 5g / L, 10g / L, 15g / L, 20g / L, 25g / L, 30g / L, 35g / L, 40g / L, 45g / L, 50g / L, 55g / L, 60g / L, 65g / L, 70g / L, 75g / L, 80g / L, 85g / L, 90g / L, 95g / L or 100g / L, which will not be elaborated here.

[0059] In some embodiments of this disclosure, the above-mentioned wet treatment process further includes: returning a portion of the overflow to the countercurrent washing step; neutralizing the remaining portion of the overflow with the leaching residue to obtain tailings slurry; the neutralization temperature is 25°C to 100°C, and / or the neutralization time is 0.5h to 8h; and / or the final pH value of the neutralization is 7.0 to 9.0.

[0060] The recycling of the overflow (returning to countercurrent washing) and the neutralization of the remainder (neutralizing with leaching residue) realize the reuse of resources and reduce waste emissions. At the same time, the neutralization treatment improves the environmental protection and resource utilization of the tailings slurry. Furthermore, the preferred neutralization temperature is 50℃~80℃, and the preferred neutralization time is 4h~6h. Furthermore, the neutralization temperature can be 25℃, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, or 100℃, or any value within the range of 25℃ to 100℃, which will not be elaborated here; the neutralization time can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, or 8h, or any value within the range of 0.5h to 8h, which will not be elaborated here; the endpoint pH value of the neutralization treatment can be 7.0, 7.5, 8.0, 8.5, or 9.0, or any value within the range of 7.0 to 9.0, which will not be elaborated here.

[0061] In some embodiments of this disclosure, a second oxidant and a second neutralizing agent are added during the above-described neutralization process. The second oxidant is selected from any one or more of the following: a mixture of oxygen and sulfur dioxide, oxygen, ozone, persulfate, hydrogen peroxide, nitrite, and perchlorate; and / or the second neutralizing agent is selected from any one or more of the following: sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, and calcium bicarbonate.

[0062] The use of a second oxidant and a second neutralizer in the neutralization process further optimized the tailings treatment process, ensuring the complete precipitation of residual metals and reducing environmental pollution. At the same time, by selecting appropriate second oxidants and second neutralizers, the resource utilization of tailings was achieved.

[0063] The precipitation method described above is used for limonite-type lateritic nickel ore, preferably with a nickel content of 0.8% to 1.8%, a cobalt content of 0.01% to 0.5%, an iron content of 40% to 50%, a magnesium content of 1% to 10%, a manganese content of 0.1% to 1.5%, and a scandium content of 10 to 80 ppm.

[0064] Furthermore, the preferred nickel-cobalt hydroxide product obtained through the above-mentioned hydrometallurgical process for laterite nickel ore has a nickel content of 39%–45.5%, a cobalt content of 3.1%–4.6%, a scandium content of 1100 ppm–1400 ppm, a magnesium content of 0.15%–0.25%, and a manganese content of 0.4%–0.9%, exhibiting excellent quality. The overall process achieves nickel recovery rates of 88%–95.5%, cobalt recovery rates of 85%–95%, and scandium recovery rates of 83%–96%. Therefore, the advantages of the hydrometallurgical process for laterite nickel ore in this disclosure not only lie in shortening the complex traditional two-stage iron and aluminum removal and two-stage nickel and cobalt precipitation processes, reducing production costs and energy consumption, but also in improving the recovery rates of nickel and cobalt, the overall scandium recovery rate, and significantly reducing the magnesium and manganese content in the nickel-cobalt hydroxide product, thereby greatly improving the quality of the nickel-cobalt oxide product.

[0065] The present disclosure will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present disclosure.

[0066] Example 1

[0067] The raw material used is limonite-type lateritic nickel ore, with a nickel content of 1.2%, a cobalt content of 0.12%, an iron content of 45%, a magnesium content of 2%, a manganese content of 0.5%, and a scandium content of 40 ppm. Referring to the flowchart of the hydrometallurgical process for lateritic nickel ore shown in Figure 1, the limonite-type lateritic nickel ore is subjected to high-pressure acid leaching. The acid-to-ore ratio is 250 kg / t ore, the acid leaching temperature is 255℃, and the acid leaching time is 1 hour. Iron-aluminum slag is added, and the final acidity is 5 g / L, yielding the leached slurry.

[0068] After liquid-solid separation, the leached slurry was subjected to countercurrent washing using a seven-stage CCD thickener to obtain washed slurry and leaching residue. Subsequently, the washed slurry underwent iron and aluminum removal treatment using limestone and oxygen. The amount of oxygen added was 5.0 times the stoichiometric ratio of ferrous iron in the washed slurry. The iron and aluminum removal treatment was performed at a temperature of 40℃ for 3 hours, with the final pH controlled at 5.0. This yielded a solution and iron-aluminum slag, with the nickel content in the slag being 3% and the cobalt content being 0.5%.

[0069] The obtained iron-aluminum slag is returned to the above high-pressure acid leaching treatment step. After removing iron and aluminum, magnesium oxide is added to the liquid for nickel-cobalt precipitation treatment. The temperature of the nickel-cobalt precipitation treatment is 40℃, the precipitation time is 3h, and the final pH of the nickel-cobalt precipitation treatment is controlled at 8.5 to obtain the precipitated slurry.

[0070] The precipitated slurry is continuously thickened and separated to obtain underflow and overflow;

[0071] The underflow was subjected to sequential washing treatments, including acidic solution washing, alkaline solution washing, and nickel-cobalt solution washing, using 0.5 wt% sulfuric acid solution, 5 wt% sodium hydroxide solution, and nickel-cobalt solution with a mass concentration of 3 g / L, to obtain nickel-cobalt hydroxide product. The mass of each of the sulfuric acid solution, sodium hydroxide solution, and nickel-cobalt solution was independently 5% of the solid mass of the nickel-cobalt hydroxide product. The temperature of each of the acidic solution washing, alkaline solution washing, and nickel-cobalt solution washing treatments was independently 60 °C, and the time for each was independently 3 h.

[0072] Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0073] Example 2

[0074] The only difference between this embodiment and Example 1 is that the final pH value of the iron and aluminum removal treatment is 4.5, resulting in a solution and iron-aluminum slag after iron and aluminum removal. The iron-aluminum slag contains 2.5% nickel and 0.3% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 44% nickel, 3.7% cobalt, 1300 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0075] Example 3

[0076] The only difference between this embodiment and Example 1 is that the final pH value of the iron and aluminum removal treatment is 5.5, resulting in a solution and iron-aluminum slag after iron and aluminum removal. The iron-aluminum slag contains 8% nickel and 0.9% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0077] Example 4

[0078] The only difference between this embodiment and Example 1 is that the final pH value of the iron and aluminum removal treatment is 3.8, resulting in a solution and iron-aluminum slag after iron and aluminum removal. The iron-aluminum slag contains 3% nickel and 0.3% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 42% nickel, 3.1% cobalt, 1100 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0079] Example 5

[0080] The only difference between this embodiment and Example 1 is that the iron-aluminum removal treatment temperature is 90°C, resulting in a solution and iron-aluminum slag after iron-aluminum removal. The iron-aluminum slag contains 2.8% nickel and 0.45% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0081] Example 6

[0082] The only difference between this embodiment and Example 1 is that the iron-aluminum removal treatment temperature is 25°C, resulting in a solution and iron-aluminum slag after iron-aluminum removal. The iron-aluminum slag contains 3.6% nickel and 0.55% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0083] Example 7

[0084] The only difference between this embodiment and Example 1 is that the iron-aluminum removal treatment time is 6 hours, resulting in a solution and iron-aluminum slag after iron-aluminum removal. The iron-aluminum slag contains 3.1% nickel and 0.55% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieves a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0085] Example 8

[0086] The only difference between this embodiment and Example 1 is that the iron-aluminum removal treatment time is 4 hours, resulting in a solution and iron-aluminum slag after iron-aluminum removal. The iron-aluminum slag contains 3.05% nickel and 0.52% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieves a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0087] Example 9

[0088] The only difference between this embodiment and Example 1 is that the amount of oxygen added is 10.0 times the stoichiometric ratio of ferrous iron in the washed slurry, resulting in a solution after iron and aluminum removal and iron-aluminum slag. The iron-aluminum slag contains 2.95% nickel and 0.45% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0089] Example 10

[0090] The only difference between this embodiment and Example 1 is that the amount of oxygen added is 1.0 times the stoichiometric ratio of ferrous iron in the washed slurry, resulting in a solution after iron and aluminum removal and iron-aluminum slag. The iron-aluminum slag contains 3.2% nickel and 0.52% cobalt by mass, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contains 40.5% nickel, 3.1% cobalt, 1100 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0091] Example 11

[0092] The only difference between this embodiment and Example 1 is that potassium persulfate and potassium carbonate were used as the first oxidant and neutralizing agent, respectively, to obtain a solution and iron-aluminum slag after iron and aluminum removal. The nickel content in the iron-aluminum slag was 2.95% and the cobalt content was 0.45%, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0093] Example 12

[0094] The only difference between this embodiment and Example 1 is that the final pH of the nickel-cobalt precipitation treatment is controlled at 9.0 to obtain a precipitated slurry, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 39% nickel, 3.7% cobalt, 1100 ppm scandium, 0.9% magnesium, and 0.9% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0095] Example 13

[0096] The only difference between this embodiment and Example 1 is that the final pH of the nickel-cobalt precipitation treatment is controlled at 7.0 to obtain a precipitated slurry, ultimately yielding nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 88%, a cobalt recovery rate of 85%, and a scandium recovery rate of 83%.

[0097] Example 14

[0098] The only difference between this embodiment and Example 1 is that the nickel-cobalt precipitation treatment temperature is 90°C, resulting in a precipitate, which ultimately yields nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.15% magnesium, and 0.4% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0099] Example 15

[0100] The only difference between this embodiment and Example 1 is that the nickel-cobalt precipitation treatment temperature is 25°C, resulting in a precipitated slurry, which ultimately yields nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.25% magnesium, and 0.55% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0101] Example 16

[0102] The only difference between this embodiment and Example 1 is that the nickel-cobalt precipitation treatment time is 6 hours, resulting in a precipitated slurry, which ultimately yields nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.15% magnesium, and 0.45% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0103] Example 17

[0104] The only difference between this embodiment and Example 1 is that the nickel-cobalt precipitation treatment time is 4 hours, resulting in a precipitated slurry, which ultimately yields nickel-cobalt hydroxide. Testing revealed that the nickel-cobalt hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.17% magnesium, and 0.48% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0105] Example 18

[0106] The only difference between this embodiment and Embodiment 1 is that the raw material used is limonite-type laterite nickel ore, with a nickel content of 0.9%, a cobalt content of 0.1%, an iron content of 45%, a scandium content of 60 ppm, a magnesium content of 1.5%, and a manganese content of 0.8%. After high-pressure acid leaching, the acid-to-ore ratio is 250 kg / t of ore, the leaching temperature is 255°C, and the leaching time is 1 hour. Iron-aluminum slag is added, and the final acidity is 5 g / L, yielding the leached slurry.

[0107] After leaching, the slurry underwent liquid-solid separation and was then countercurrently washed using a seven-stage CCD thickener to obtain a washed slurry and leaching residue. Subsequently, the washed slurry was further treated with limestone and potassium persulfate to remove iron and aluminum. The amount of potassium persulfate added was 5.0 times the stoichiometric ratio of ferrous iron in the washed slurry. The treatment temperature was 40℃, the treatment time was 3 hours, and the final pH of the treatment was controlled at 5.0. This yielded a solution and iron-aluminum slag. The iron-aluminum slag contained 3% nickel and 0.5% cobalt by mass.

[0108] The obtained iron-aluminum slag is returned to the aforementioned high-pressure acid leaching process. Magnesium oxide is reacted with a 3 g / L magnesium-containing solution to generate active magnesium hydroxide. After iron and aluminum removal, the solution is added to the active magnesium hydroxide for nickel-cobalt precipitation. The precipitation temperature is 40℃, the precipitation time is 3 hours, and the final pH of the precipitation is controlled at 8.5, resulting in a precipitated slurry, which ultimately yields nickel hydroxide. Analysis shows that the nickel-cobalt hydroxide contains 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieves a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0109] Example 19

[0110] The only difference between this embodiment and Embodiment 1 is that the raw material used is limonite-type lateritic nickel ore, with a nickel content of 1.2%, an iron content of 45%, and a magnesium content of 2%. After high-pressure acid leaching, the acid-to-ore ratio is 350 kg / t of ore, the leaching temperature is 280℃, and the leaching time is 8 hours. Iron-aluminum slag is added, and the final acidity is 30 g / L, yielding a leached slurry, ultimately producing nickel hydroxide. Testing revealed that the nickel hydroxide contained 45% nickel, 4% cobalt, 1400 ppm scandium, 0.2% magnesium, and 0.5% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95.5%, a cobalt recovery rate of 95%, and a scandium recovery rate of 96%.

[0111] Example 20

[0112] The only difference between this embodiment and Example 1 is that the underflow was sequentially treated with acidic, alkaline, and nickel-cobalt-containing solutions using a 5wt% sulfuric acid solution, a 40wt% sodium hydroxide solution, and a 50g / L nickel-cobalt solution to obtain nickel-cobalt hydroxide product. The amounts of each of the sulfuric acid solution, sodium hydroxide solution, and nickel-cobalt-containing solution were independently 1% of the solid content of the nickel-cobalt hydroxide product. The temperatures for each of the acidic, alkaline, and nickel-cobalt-containing solution washing treatments were independently 80°C, and the times for each were independently 6 hours. Testing revealed that the nickel-cobalt hydroxide contained 45.5% nickel, 4.6% cobalt, 1400ppm scandium, 0.17% magnesium, and 0.45% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0113] Example 21

[0114] The only difference between this embodiment and Example 1 is that the underflow was sequentially treated with acidic solution washing, alkaline solution washing, and nickel-cobalt solution washing using a 0.4 wt% sulfuric acid solution, a 4 wt% sodium hydroxide solution, and a 2 g / L nickel-cobalt solution to obtain nickel-cobalt hydroxide product. The amounts of sulfuric acid solution, sodium hydroxide solution, and nickel-cobalt solution used were each independently 3% of the solid weight of the nickel-cobalt hydroxide product. The temperature for each of the acidic solution washing, alkaline solution washing, and nickel-cobalt solution washing was independently 50°C, and the time for each was independently 4 hours. Testing revealed that the nickel-cobalt hydroxide contained 44.5% nickel, 3.8% cobalt, 1400 ppm scandium, 0.25% magnesium, and 0.53% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 95%, a cobalt recovery rate of 94.5%, and a scandium recovery rate of 96%.

[0115] Comparative Example 1

[0116] The raw material is limonite-type laterite nickel ore, with a nickel content of 1.2%, an iron content of 45%, and a magnesium content of 2%. After high-pressure acid leaching, the acid-to-ore ratio is 250 kg / t of ore, the leaching temperature is 255℃, and the leaching time is 1 hour. Iron-aluminum slag is added, and the final acidity is 30 g / L, yielding the leached slurry.

[0117] After leaching, the slurry was subjected to a seven-stage CCD thickener countercurrent washing process, followed by a primary iron and aluminum removal treatment, a secondary iron and aluminum removal treatment, a primary nickel-cobalt immersion treatment, and a secondary nickel-cobalt immersion treatment. The washing process yielded nickel-cobalt hydroxide. Specifically, the primary iron and aluminum removal treatment was performed using limestone at a temperature of 80℃ for 4 hours, with a final pH of 3.8; the secondary iron and aluminum removal treatment was performed using limestone at a temperature of 70℃ for 4 hours, with a final pH of 4.8; the primary nickel-cobalt immersion treatment was performed using sodium hydroxide at a temperature of 60℃ for 3 hours, with a final pH of 7.8; and the secondary nickel-cobalt immersion treatment was performed using sodium hydroxide at a temperature of 50℃ for 3 hours, with a final pH of 8.4.

[0118] Testing revealed that the nickel-cobalt hydroxide contained 39% nickel, 3.5% cobalt, 300 ppm scandium, 1.5% magnesium, and 6% manganese, indicating excellent quality. The overall process achieved a nickel recovery rate of 91%, a cobalt recovery rate of 90%, and a scandium recovery rate of 25%.

[0119] As can be seen from the above description, the embodiments of this disclosure achieve the following technical effects:

[0120] The core of this disclosure lies in providing a short-process hydrometallurgical treatment method for laterite nickel ore. Through acid leaching, liquid-solid separation, and countercurrent washing, a washed slurry and leaching residue are obtained. The washed slurry undergoes a primary iron-aluminum removal process to obtain a post-iron-aluminum solution and iron-aluminum slag. The post-iron-aluminum solution undergoes a primary nickel-cobalt precipitation and post-treatment step. The iron-aluminum slag is returned to the acid leaching process, thereby achieving efficient enrichment of nickel and cobalt and improving the quality of the nickel-cobalt hydroxide product. The advantages of this disclosure are that it shortens the complex process of traditional two-stage iron-aluminum removal and two-stage nickel-cobalt precipitation, reducing production costs and energy consumption, while improving the recovery rate of nickel and cobalt, the overall scandium recovery rate, and the quality of the nickel-cobalt oxide product.

[0121] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A hydrometallurgical process for processing lateritic nickel ore, wherein the lateritic nickel ore comprises limonite-type lateritic nickel ore and / or residual lateritic nickel ore, characterized in that, The wet processing technology includes: Step S1: The laterite nickel ore is subjected to acid leaching treatment with inorganic acid to obtain leached slurry; Step S2: The leached slurry is subjected to liquid-solid separation and countercurrent washing in sequence to obtain washed slurry and leaching residue; Step S3: Add a first oxidant and a first neutralizing agent to the washed slurry to remove iron and aluminum, and obtain a solution and iron and aluminum slag after iron and aluminum removal. Step S4: The solution after iron and aluminum removal is subjected to nickel and cobalt precipitation treatment to obtain a precipitated slurry; Step S5: The precipitated slurry is continuously subjected to thickening and separation treatment to obtain underflow and overflow; Step S6: The underflow is washed and treated sequentially to obtain nickel-cobalt hydroxide product; In this step, the iron and aluminum slag is returned to the acid leaching treatment.

2. The hydrometallurgical process for laterite nickel ore according to claim 1, characterized in that, In step S3, the temperature of the iron and aluminum removal treatment is 25℃~100℃, the time of the iron and aluminum removal treatment is 0.5h~8h; and / or the final pH value of the iron and aluminum removal treatment is 3.8~5.5; and / or, the mass content of nickel in the iron and aluminum slag is 1%~8%, and the mass content of cobalt is 0.1%~0.9%.

3. The wet processing technology for laterite nickel ore according to claim 1, characterized in that, In step S3, the first oxidant is selected from any one or more of the following: a mixture of oxygen and sulfur dioxide, oxygen, ozone, persulfate, hydrogen peroxide, nitrite, and perchlorate, and / or the amount of the first oxidant added is 1.0 to 10.0 times the stoichiometric ratio of ferrous iron in the washed slurry.

4. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S3, the first neutralizing agent is selected from any one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, calcium bicarbonate, limestone, magnesia powder, magnesite, dolomite, and marble.

5. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S4, the temperature of the nickel-cobalt precipitation treatment is 25℃~100℃, the time of the nickel-cobalt precipitation treatment is 0.5h~8h; and / or the final pH value of the nickel-cobalt precipitation treatment is 7.0~9.

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6. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S4, the process of precipitating nickel and cobalt includes: directly adding the precipitant to the solution after removing iron and aluminum to carry out the precipitating nickel and cobalt treatment; Alternatively, a magnesium-containing solution can be used to first react with a precipitant to generate active magnesium hydroxide, and then the active magnesium hydroxide can be added to the solution after iron and aluminum removal to carry out the nickel-cobalt precipitation treatment. And / or the precipitant is selected from any one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, and calcium bicarbonate.

7. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S1, the acid leaching temperature is 90℃~280℃, the acid leaching time is 0.5h~8h, and / or the final acidity of the acid leaching is 0.1g / L~50g / L; and / or the acid leaching pressure is 1MPa~4MPa.

8. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S1, the inorganic acid is selected from any one or more of sulfuric acid, hydrochloric acid, and nitric acid.

9. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S2, the liquid-solid separation method is thickener separation or filter press separation; and / or the countercurrent washing method is any one of multi-stage thickener series countercurrent washing, filter press on-machine countercurrent washing, and slurry countercurrent washing.

10. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, In step S6, the post-washing treatment process includes sequential acidic solution washing, alkaline solution washing, and nickel-cobalt-containing solution washing.

11. The hydrometallurgical process for laterite nickel ore according to claim 10, characterized in that, In step S6, the amount of acidic solution used for the acidic solution washing treatment is 0.01% to 100% of the solid weight of the nickel-cobalt hydroxide product; and / or the mass concentration of the acidic solution is 0.01% to 5 wt%, the acidic solution is selected from any one or more of sulfuric acid solution, hydrochloric acid solution, nitric acid solution, carbonic acid solution and organic acid solution; and / or the temperature of the acidic solution washing treatment is 25℃ to 100℃, and the time of the acidic solution washing treatment is 0.5h to 8h.

12. The hydrometallurgical process for laterite nickel ore according to claim 10, characterized in that, In step S6, the amount of alkaline solution used for the alkaline solution washing treatment is 0.01% to 100% of the solid weight of the nickel-cobalt hydroxide product; and / or the mass concentration of the alkaline solution is 0.1% to 40 wt%, and the alkaline solution is selected from one or more of sodium hydroxide solution, potassium hydroxide solution, ammonia water, and carbonate solution; and / or the temperature of the alkaline solution washing treatment is 25℃ to 100℃, and the time of the alkaline solution washing treatment is 0.5h to 8h.

13. The hydrometallurgical process for laterite nickel ore according to claim 10, characterized in that, In step S6, the mass of the nickel-cobalt solution used for washing is 0.01% to 100% of the solid mass of the nickel-cobalt hydroxide product; and / or the mass concentration of nickel and cobalt in the nickel-cobalt solution is 0.1 g / L to 100 g / L, and the nickel-cobalt solution is selected from any one or more of leaching solution, solution before iron and aluminum removal, solution after iron and aluminum removal, and self-prepared nickel-cobalt solution; and / or the temperature of the nickel-cobalt solution washing treatment is 25℃ to 100℃, and the washing time of the nickel-cobalt solution washing treatment is 0.5 h to 8 h.

14. The hydrometallurgical process for laterite nickel ore according to any one of claims 1 to 3, characterized in that, The wet processing technology also includes: A portion of the overflow is returned to the countercurrent washing step; The remaining overflow is neutralized with the leaching residue to obtain tailings slurry; The neutralization treatment temperature is 25℃~100℃, and / or the neutralization treatment time is 0.5h~8h; and / or the final pH value of the neutralization treatment is 7.0~9.

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15. The hydrometallurgical process for laterite nickel ore according to claim 14, characterized in that, During the neutralization process, a second oxidant and a second neutralizing agent are added. The second oxidant is selected from any one or more of the following: a mixture of oxygen and sulfur dioxide, oxygen, ozone, persulfate, hydrogen peroxide, nitrite, and perchlorate; and / or the second neutralizing agent is selected from any one or more of the following: sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, magnesium carbonate, magnesium bicarbonate, ammonium carbonate, ammonium bicarbonate, calcium oxide, magnesium oxide, sodium hydroxide, potassium hydroxide, ammonia, calcium hydroxide, magnesium hydroxide, calcium carbonate, and calcium bicarbonate.

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