Method for extracting nickel, cobalt and copper by using dolomite active oxide

Abstract

The invention provides a method for extracting nickel, cobalt and copper by using dolomite active oxides, and belongs to the technical field of metal separation and recovery. According to the method, the reduced dolomite is calcined in the hydrogen atmosphere, carbon in dolomite carbonate can be converted into CO which is high in additional value and easy to activate in situ, meanwhile, the reduced dolomite is refined in the hydrogen atmosphere, sintering of metal oxide can be prevented, and the obtained active metal oxide precipitator has the oxygen vacancy defect; compared with common MgO and CaO, the MgO / CaO composite material has higher activity in cobalt, nickel and copper precipitation, realizes efficient precipitation of cobalt, nickel and copper, and has important application value in separation of metals in laterite-nickel ore, cobalt-copper ore and lithium ion battery positive active substances.

Description

Technical Field

[0001] This invention relates to the field of metal separation and recycling technology, specifically to a method for extracting nickel, cobalt, and copper using dolomite active oxides. Background Technology

[0002] Nickel, cobalt, and copper, as metallic materials with special properties, are widely used in many industrial fields. Cobalt-copper ore is rich in copper and cobalt, while laterite nickel ore contains abundant nickel and cobalt. In addition, the positive electrode active material of lithium-ion secondary batteries also contains a large amount of cobalt and nickel, along with manganese, copper, aluminum, lithium, and other elements. To achieve efficient recovery, cobalt, nickel, and copper must be accurately separated from other impurity elements. However, the acid leaching process currently used in industry often results in the leaching of coexisting elements such as iron and manganese, thus interfering with the subsequent refining process of nickel, cobalt, and copper.

[0003] Commonly used alkaline precipitants, such as Na₂CO₃ and NaOH, present challenges in pH control and are prone to localized over-alkalinity. To address these issues, researchers have attempted to use MgO as a precipitant to separate cobalt and nickel from cobalt-copper ore and laterite nickel ore. However, MgO's weak alkalinity makes complete precipitation of cobalt and nickel difficult. Therefore, achieving efficient separation of cobalt, nickel, and copper has become a critical problem urgently needing to be solved in industrial practice.

[0004] Dolomite is a naturally occurring CaCO3·MgCO3 double salt with abundant reserves, wide distribution, and high purity. Due to its excellent surface adsorption properties, ability to provide calcium and magnesium sources, superior fire resistance, and thermal insulation properties, dolomite has been widely used in various fields such as adsorbents and calcium-magnesium raw material preparation. The preparation of magnesium-calcium raw materials from dolomite often requires high-temperature calcination in air, but this process involves large amounts of CO2 emissions, resulting in high energy consumption and significant carbon emissions. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for extracting nickel, cobalt and copper using dolomite active oxides. The method provided by this invention can convert carbon in dolomite into high-value CO gas and achieve efficient separation and precipitation of cobalt, nickel and copper.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for extracting nickel, cobalt, and copper using dolomite active oxide, comprising the following steps: Dolomite was calcined in a reducing atmosphere containing H2 to obtain an active metal oxide precipitant and a mixed gas containing H2 and CO. The active metal oxide precipitant is mixed with a solution containing target metal ions, and a precipitation reaction is carried out under stirring to obtain a target ion precipitate. The target metal includes one or more of nickel, cobalt, and copper.

[0007] Preferably, the dolomite has a particle size of 200 nm to 10 μm; The volume concentration of hydrogen in the reducing atmosphere containing H2 is 10~100%.

[0008] Preferably, the calcination temperature is 600~800℃, and the holding time is 5~60min; The flow rate of hydrogen in the reducing atmosphere during calcination is 0~100 mL / min.

[0009] Preferably, the active metal oxide precipitant is added in the form of a slurry, and the concentration of the active metal oxide precipitant slurry is 1~50 g / L.

[0010] Preferably, the molar ratio of the active metal oxide precipitant to the target metal ion is 0.1 to 5:1.

[0011] Preferably, the precipitation reaction is carried out at a temperature of 30~80℃; The precipitation reaction time is 10 min to 6 h; The stirring rate for the precipitation reaction is 100-400 rpm.

[0012] Preferably, the precipitation reaction is followed by room temperature aging for 5 to 30 minutes.

[0013] Preferably, the solution containing the target metal ions includes one or more of the following: laterite nickel ore leaching solution, cobalt copper ore leaching solution, and lithium-ion battery positive electrode active material extraction solution.

[0014] Preferably, the mass concentration of the target metal ion in the solution containing the target metal ion is 0.1~10 g / L.

[0015] Preferably, when the solution containing the target metal ions contains multiple target metal ions, the copper precipitate precipitates before the nickel and cobalt precipitates.

[0016] This invention provides a method for extracting nickel, cobalt, and copper using dolomite active oxides, comprising the following steps: calcining dolomite in a reducing atmosphere containing H2 to obtain an active metal oxide precipitant and a mixed gas containing H2 and CO; mixing the active metal oxide precipitant with a solution containing target metal ions, and carrying out a precipitation reaction under stirring to obtain a target ion precipitate, wherein the target metal includes one or more of nickel, cobalt, and copper. On one hand, this invention, by calcining and reducing dolomite in a hydrogen atmosphere, can lower the decomposition temperature of dolomite to 500-600℃, significantly reducing energy consumption compared to metal oxides refined in an air atmosphere; on the other hand, calcining and reducing dolomite in a hydrogen atmosphere can convert carbon in dolomite carbonates in situ into easily activated CO with high added value. The exhaust gas after calcination is mainly a mixture of H2 and CO, which can be easily synthesized into aromatics, methanol, ethanol, and other oxygen-containing compounds through Fischer-Tropsch synthesis or other synthesizer conversion technologies, thereby converting CO into liquid fuels and various high-value chemicals, in line with the "carbon reduction" development concept.

[0017] This invention provides an active metal oxide precipitant obtained by calcining and reducing dolomite with hydrogen. The main components are active MgO and active CaO. This precipitant exhibits suitable alkalinity during the precipitation of cobalt, nickel, and copper, avoiding localized over-alkaliness. Compared to metal oxides refined in an air atmosphere, the hydrogen-reduced dolomite precipitate process prevents metal oxide sintering. The resulting active metal oxide precipitant possesses oxygen vacancy defects, exhibiting higher activity than ordinary MgO and CaO in the precipitation of cobalt, nickel, and copper. This enables highly efficient precipitation of cobalt, nickel, and copper, and has significant application value for metal separation in lateritic nickel ore, cobalt-copper ore, and lithium-ion battery cathode active materials. Attached Figure Description

[0018] Figure 1 Thermogravimetric analysis (TGA) diagram of dolomite decomposition under hydrogen atmosphere; Figure 2 Thermogravimetric analysis diagram of dolomite decomposition in air; Figure 3 XRD patterns of the products obtained from dolomite under different calcination temperatures in hydrogen atmosphere; Figure 4 This is a mass spectrum of the gaseous products of dolomite under hydrogen conditions as the calcination temperature changes. Figure 5 This is a mass spectrum of the gaseous products of dolomite under air conditions as the calcination temperature changes. Figure 6 The graph shows the gaseous products obtained from dolomite under different calcination temperatures under hydrogen conditions. Figure 7 SEM image of the metal oxide obtained after calcining dolomite with hydrogen at 750℃. Figure 8 TEM image of the metal oxide obtained after calcining dolomite with hydrogen at 750℃; Figure 9 SEM image of the metal oxide obtained after dolomite is calcined in air at 800℃. Detailed Implementation

[0019] This invention provides a method for extracting nickel, cobalt, and copper using dolomite active oxide, comprising the following steps: Dolomite was calcined in a reducing atmosphere containing H2 to obtain an active metal oxide precipitant and a mixed gas containing H2 and CO. The active metal oxide precipitant is mixed with a solution containing target metal ions, and a precipitation reaction is carried out under stirring to obtain a target ion precipitate. The target metal includes one or more of nickel, cobalt, and copper.

[0020] This invention involves calcining dolomite in a reducing atmosphere containing H2 to obtain an active metal oxide precipitant and a mixed gas containing H2 and CO. In this invention, the main component of the dolomite is calcium magnesium carbonate, with a magnesium-to-calcium molar ratio of 0.5–1.8:1, more preferably 0.8–1.2:1, and even more preferably 1:1. In this invention, the particle size of the dolomite is preferably 200 nm–10 μm, more preferably 500 nm–5 μm.

[0021] In this invention, the reducing atmosphere containing H2 is preferably a pure H2 atmosphere or a mixed atmosphere of H2 and an inert gas, wherein the inert gas is preferably argon. In this invention, the volume concentration of hydrogen in the reducing atmosphere containing H2 is preferably 10-100%, more preferably 30-80%, and even more preferably 50%. In this invention, the flow rate of hydrogen in the reducing atmosphere during calcination is preferably 0-100 mL / min, and preferably not 0, more preferably 20-80 mL / min, and even more preferably 50 mL / min.

[0022] In this invention, the calcination temperature is preferably 600-800℃, more preferably 650-800℃, and even more preferably 750-800℃. As a specific embodiment of this invention, the calcination temperature can be 600℃, 650℃, 700℃, 750℃, or 800℃. In this invention, the heating rate to the calcination temperature is preferably 5-20℃ / min, more preferably 10℃ / min. In this invention, the holding time for calcination is preferably 5-60 min, more preferably 10-40 min, and even more preferably 20-30 min.

[0023] In this invention, the main components of the active metal oxide precipitant are MgO and CaO, wherein the molar ratio of magnesium to calcium is preferably 0.5~1.8:1, more preferably 0.8~1.2:1, and even more preferably 1:1. In this invention, the active metal oxide precipitant is denoted as XO.

[0024] After obtaining the active metal oxide precipitant, the present invention mixes the active metal oxide precipitant with a solution containing target metal ions and carries out a precipitation reaction under stirring to obtain a target ion precipitate. The target metal includes one or more of nickel, cobalt, and copper. In the present invention, the active metal oxide precipitant is preferably added in slurry form, and the preparation method of the active metal oxide precipitant slurry preferably includes the following steps: The active metal oxide precipitant is mixed with water and subjected to ultrasound to obtain an active metal oxide precipitant slurry.

[0025] In this invention, the power of the ultrasound is preferably 200-500W, more preferably 300-400W; the duration is preferably 5-10 min, more preferably 6-8 min. In this invention, the concentration of the active metal oxide precipitant slurry is preferably 1-50 g / L, more preferably 5-30 g / L, and even more preferably 10-20 g / L.

[0026] In this invention, the active metal oxide precipitant slurry is preferably added by dripping, and the dripping rate is preferably 0.1 to 0.2 mL every 5 to 10 seconds. The dripping rate can be scaled up proportionally according to the volume of the reaction system, and the total dripping time is preferably controlled to be completed within 30 to 180 minutes.

[0027] In this invention, the solution containing the target metal ions preferably includes one or more of the following: laterite nickel ore leaching solution, cobalt-copper ore leaching solution, and lithium-ion battery positive electrode active material extraction solution. In this invention, the above leaching solutions are preferably acid leaching solutions. In this invention, the mass concentration of the target metal ions in the solution containing the target metal ions is preferably 0.1~10 g / L, more preferably 1~8 g / L, and even more preferably 2~5 g / L.

[0028] In this invention, the molar ratio of the active metal oxide precipitant to the target metal ion is preferably 0.1 to 5:1, more preferably 0.5 to 4:1, and even more preferably 1 to 3:1. Specifically, it can be 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 4:1, or 5:1.

[0029] In this invention, the precipitation reaction is preferably carried out under water bath conditions. The temperature of the precipitation reaction is preferably 60-70°C, more preferably 65°C, and the time is preferably 10 min-6 h, more preferably 30 min-5 h, and even more preferably 1-3 h. The stirring rate of the precipitation reaction is preferably 300 rpm.

[0030] In this invention, the precipitation reaction is followed by room temperature aging, the room temperature aging time of which is preferably 5 to 30 minutes, more preferably 10 to 20 minutes.

[0031] In this invention, the target ion precipitate is preferably a cobalt, nickel, or copper hydroxide precipitate.

[0032] In this invention, when the solution containing the target metal ion contains multiple target metal ions, the copper precipitate precipitates before the nickel and cobalt precipitates. When the solution containing the target metal ion contains copper ions and other target metal ions, this invention preferably first adds a first portion of active metal oxide precipitant to the solution containing the target metal ions and mixes it with the solution containing the target metal ions, and carries out a first precipitation reaction under stirring conditions to perform solid-liquid separation, resulting in a copper precipitate and a filtrate as the solid phase. A second part of active metal oxide precipitant is added to the filtrate, and a second precipitation reaction is carried out under stirring to obtain cobalt and / or nickel precipitates.

[0033] In this invention, the reaction conditions for the first precipitation reaction and the second precipitation reaction are the same as the optional conditions for the precipitation reaction described above, and will not be repeated here.

[0034] The following detailed description of the method for extracting nickel, cobalt, and copper using dolomite active oxide provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0035] Example 1 (1) Take 500 mg of dolomite (magnesium-calcium molar ratio 1:1, particle size 200~500 nm) and place it in a quartz tube with a diameter of 10 mm. 100% hydrogen gas is introduced for calcination at a flow rate of 100 mL / min. The heating rate of the tube furnace is controlled at 10 °C / min. The temperature is raised to 750 °C, held for 10 min, and then cooled naturally to obtain the calcined product at 750 °C, which is the active metal oxide precipitant. The gas composition after calcination is a mixture of H2 and CO.

[0036] Figure 1 This is a thermogravimetric analysis (TGA) diagram of dolomite decomposition under hydrogen atmosphere. Figure 2The thermogravimetric analysis (TGA) diagram shows the decomposition of dolomite in air. The TGA diagram indicates that dolomite begins to decompose above 538°C under 10% hydrogen conditions and completely decomposes above 746°C. Compared to dolomite calcined in air, the decomposition temperature is approximately 76°C lower.

[0037] Figure 3 The XRD patterns of the products obtained by calcining dolomite under different hydrogen conditions are shown. The XRD patterns show that dolomite begins to decompose at 600℃ under 100% hydrogen conditions and completely decomposes into a mixture of MgO and CaO at 650℃.

[0038] Figure 4 This is a mass spectrum of the gaseous products of dolomite under hydrogen conditions, as the calcination temperature changes. Figure 5 This is a mass spectrum of the gaseous products of dolomite under air conditions as calcination temperature changes. The mass spectrum shows that dolomite begins to decompose at 489℃ under hydrogen conditions and completely decomposes above 750℃, which is approximately 179℃ lower than the decomposition temperature of dolomite calcined in air.

[0039] Figure 6 The graph shows the gaseous products obtained from dolomite under different calcination temperatures under hydrogen conditions. It can be seen that a small amount of CO appears at 550℃ and 600℃, with a conversion rate and selectivity of 100%; CO2 appears above 650℃, and the proportion of CO increases with increasing temperature.

[0040] Figure 7 This is a SEM image of the metal oxide obtained after calcining dolomite with hydrogen at 750℃. Figure 8 The image shows a TEM image of the metal oxide obtained after calcining dolomite with hydrogen at 750℃. The SEM and TEM images show that the dolomite has a granular structure, and the particles actually become smaller after calcination with 100% hydrogen at 750℃.

[0041] (2) To simulate the composition of cobalt-copper ore acid leaching solution, CoCl2·6H2O, CuCl2, and MgCl2 were dissolved in deionized water to prepare 100 mL of solution containing cobalt (1.08 g / L), copper (0.56 g / L), and magnesium (1.24 g / L). The solution was placed in a water bath at 60°C and stirred at 300 rpm.

[0042] Weigh 51 mg of the metal oxide product obtained from calcination at 750℃ in step (1) (making n(XO) / nCu = 1.2), add 2 mL of deionized water to prepare a metal oxide slurry, and sonicate in an ultrasonic bath for 5 min. Add 0.2 mL of the metal oxide slurry every 10 s. From the addition of the metal oxide slurry, bathe in a water bath at 60℃ for 30 min, then age at room temperature for 30 min, and filter. ICP analysis results show that after the addition of the precipitant, Cu 2+The precipitation rate was 98.3%, Co 2+ The retention rate was 98.3%.

[0043] (3) Take 50 mL of the filtrate obtained from step (2) and place it in a water bath at 60°C with a stirring speed of 300 rpm. Weigh 88.3 mg of the metal oxide product obtained from calcination at 750°C in step (1) (n(XO) / nCo=2), add 2 mL of deionized water to prepare a metal oxide slurry, and shake it in an ultrasonic instrument for 5 min. Add 0.2 mL of the metal oxide slurry every 10 s to prevent local over-alkali. From the time the metal oxide slurry is added, the water bath time in the 60°C water bath is 10 min, followed by aging at room temperature for 30 min, and then filtration. ICP analysis results show that after the addition of the precipitant, Co 2+ The sedimentation rate was 99.8%.

[0044] Example 2 Take 50 mL of the filtrate obtained from step (2) of Example 1 and place it in a water bath at 60°C for 10 min with a stirring speed of 300 rpm. Weigh 132.5 mg of the metal oxide product (n(XO) / nCo=3) obtained from calcination at 750°C in step (1) of Example 1, add 4 mL of deionized water to prepare a metal oxide slurry, and shake in an ultrasonic instrument for 5 min. Add 0.1 mL of the metal oxide slurry every 2 s. From the addition of the metal oxide slurry, the water bath time is 10 min at 60°C, followed by aging at room temperature for 30 min, and then filtration. ICP analysis results show that after the addition of the precipitant, Co 2+ The sedimentation rate was 99.9%.

[0045] Example 3 CoCl2·6H2O, CuCl2, and MgCl2 were dissolved in deionized water to prepare a 100 mL solution containing cobalt (1.08 g / L), copper (0.56 g / L), and magnesium (1.24 g / L). The solution was placed in a 70°C water bath and stirred at 300 rpm. 51 mg of the metal oxide product obtained by calcination at 750°C in step (1) of Example 1 (n(XO) / nCu=1.2) was weighed and added to 2 mL of deionized water to prepare a metal oxide slurry. The slurry was then ultrasonicated for 5 min. 0.2 mL of the metal oxide slurry was added every 10 s. From the addition of the metal oxide slurry, the slurry was kept in a 70°C water bath for 10 min, followed by aging at room temperature for 30 min, and then filtered. ICP analysis showed that after the addition of the precipitant, Cu... 2+ The precipitation rate was 98.4%, Co 2+ The retention rate was 98.2%.

[0046] Example 4 Take 50 mL of the filtrate obtained from step (2) of Example 1, place it in a water bath at 60°C for 10 min, and stir at 300 rpm. Weigh 66.2 mg of the metal oxide product obtained from calcination at 750°C in step 1 of Example 1 (n(XO) / nNi=1.5), add 1.5 mL of deionized water to prepare a metal oxide slurry, and shake in an ultrasonic bath for 5 min. Add 0.1 mL of the metal oxide slurry every 2 s. From the addition of the metal oxide slurry, the water bath time in the 60°C water bath is 60 min, followed by aging at room temperature for 30 min, and then filtration. ICP analysis results show that after the addition of the precipitant, Co 2+ The sedimentation rate was 99.8%.

[0047] Example 5 To simulate the composition of laterite nickel ore acid leaching solution, CoCl2·6H2O, NiCl2, and MgCl2 were dissolved in deionized water to prepare a 50 mL solution containing nickel (1 g / L), cobalt (0.1 g / L), and magnesium (15 g / L). This solution was placed in a 60°C water bath and stirred at 300 rpm. 67.5 mg of the metal oxide product obtained from calcination at 750°C in step (1) of Example 1 (n(XO) / n(Co+Ni)=1.5) was weighed and added to 3 mL of deionized water to prepare a metal oxide slurry. The slurry was ultrasonically agitated for 10 min, with 0.1 mL of the slurry added every 2 minutes. The slurry was kept in a 60°C water bath for 3 h, followed by aging at room temperature for 30 min. The filtrate and precipitate were then separated by filtration. ICP analysis showed that the precipitation rate of Ni was 94.2% and the precipitation rate of Co was 98.6% after the addition of the precipitant.

[0048] Example 6 CoCl2·6H2O, NiCl2, and MgCl2 were dissolved in deionized water to prepare a 50 mL solution containing nickel (1 g / L), cobalt (0.1 g / L), and magnesium (15 g / L). The solution was placed in a water bath at 60°C and stirred at 300 rpm. 112.8 mg of the metal oxide product obtained by calcination at 750°C in step (1) of Example 1 (n(XO) / n(Co+Ni)=2.5) was weighed and added to 5.6 mL of deionized water to prepare a 20 g / L metal oxide slurry. The slurry was ultrasonically agitated for 5 min, and 0.1 mL of the slurry was added every 2 s. The slurry was then kept in a water bath at 60°C for 10 min, followed by aging at room temperature for 30 min. The filtrate and precipitate were then separated by filtration. ICP analysis showed that the precipitation rate of Ni was 97.9% and the precipitation rate of Co was 97.9% after the addition of the precipitant.

[0049] Comparative Example 1 (1) Take 500 mg of dolomite (particle size 200~500 nm) and place it in a quartz tube with a diameter of 10 mm. Pour air through the tube and calcine at a flow rate of 100 mL / min. Control the heating rate of the tube furnace at 10 °C / min, raise the temperature to 800 °C, hold for 10 min, and then allow it to cool naturally to obtain the calcined product at 800 °C. Figure 2 The thermogravimetric analysis shows that dolomite begins to decompose above 614℃ and completely decomposes above 760℃ under air conditions. From... Figure 5 The mass spectrometry results show that dolomite begins to decompose above 668℃ under air conditions and completely decomposes above 840℃. Figure 9 SEM image of the metal oxide obtained after dolomite is calcined in air at 800℃.

[0050] (2) Dissolve CoCl2·6H2O, NiCl2·6H2O, and MgCl2 in deionized water to prepare a 50 mL solution containing nickel (1 g / L), cobalt (0.1 g / L), and magnesium (15 g / L). Place the solution in a water bath at 60°C and stir at 300 rpm. Weigh 90.2 mg of the metal oxide product obtained by calcination at 800°C in step (1) (n(XO) / n(Co+Ni)=1.5), add 3 mL of deionized water to prepare a metal oxide slurry, and sonicate in an ultrasonic bath for 5 min. Add 0.1 mL of the metal oxide slurry every 0.2 min. From the time the metal oxide slurry is added, the water bath time in the 60°C water bath is 10 min, followed by aging at room temperature for 30 min. Filter to separate the filtrate and precipitate. ICP analysis results show that the precipitation rate of Ni is 55.9% and the precipitation rate of Co is 78.9% after the addition of the precipitant.

[0051] Comparative Example 2 CoCl₂·6H₂O, NiCl₂·6H₂O, and MgCl₂ were dissolved in deionized water to prepare a 50 mL solution containing nickel (1 g / L), cobalt (0.1 g / L), and magnesium (15 g / L). This solution was placed in a 60°C water bath and stirred at 300 rpm. Commercial CaO and MgO with a molar ratio of 1:1 (according to the ratio n(CaO+MgO) / n(Co+Ni)=1.5, i.e., CaO: 39.3 mg, MgO: 28.2 mg) were weighed and added to 1.5 mL of deionized water to prepare a metal oxide slurry. The slurry was ultrasonicated for 5 min, with 0.1 mL of the slurry added every 0.2 min. The slurry was then incubated in a 60°C water bath for 10 min, followed by aging at room temperature for 30 min. The filtrate and precipitate were then separated by filtration. ICP analysis showed that the precipitation rate of Ni was 93.0% and the precipitation rate of Co was 95.4% after the addition of the precipitant.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for extracting nickel, cobalt, copper using dolomite active oxides, characterized by, The method comprises the following steps: calcining dolomite in a reducing atmosphere containing H2 to obtain an active metal oxide precipitant and a mixed gas containing H2 and CO; mixing the active metal oxide precipitant with a solution containing target metal ions, and performing a precipitation reaction under stirring to obtain target ion precipitates, the target metal including one or more of nickel, cobalt and copper.

2. The method of claim 1, wherein, The particle size of the dolomite is 200 nm to 10 μm. The volume concentration of hydrogen in the reducing atmosphere containing H2 is 10 to 100%.

3. The method according to claim 1 or 2, characterized in that, The calcination temperature is 600 to 800 ℃, and the holding time is 5 to 60 min. The flow rate of hydrogen in the reducing atmosphere during the calcination is 0 to 100 mL / min.

4. The method of claim 1, wherein, The active metal oxide precipitant is added in the form of a slurry, and the concentration of the active metal oxide precipitant slurry is 1 to 50 g / L.

5. The method according to claim 1 or 4, characterized in that, The molar ratio of the active metal oxide precipitant to the target metal ions is 0.1 to 5:

1.

6. The method of claim 1, wherein, The precipitation reaction temperature is 30 to 80 ℃. The precipitation reaction time is 10 min to 6 h. The stirring rate of the precipitation reaction is 100 to 400 rpm.

7. The method according to claim 1 or 6, characterized in that, The precipitation reaction is followed by room temperature aging, and the room temperature aging time is 5 to 30 min.

8. The method of claim 1, wherein, The solution containing target metal ions includes one or more of laterite nickel ore leaching liquor, cobalt-copper ore leaching liquor and lithium ion battery positive active material extraction liquor.

9. The method according to claim 1 or 8, characterized in that, The mass concentration of the target metal ions in the solution containing target metal ions is preferably 0.1 to 10 g / L.

10. The method of claim 1, wherein, When the solution containing target metal ions contains multiple target metal ions, the copper precipitates are precipitated first, followed by the nickel precipitates and the cobalt precipitates.

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