Method for preparing nickel sulfate solution from high-nickel low-copper high-iron high-sulfur material

Abstract

The invention relates to a method for preparing a nickel sulfate solution from a high-nickel, low-copper, high-iron and high-sulfur material. The method comprises the following steps: a normal-pressure slurrying and proportioning stage; a first normal pressure leaching stage; a second-stage normal-pressure leaching stage; a first-stage pressure leaching stage and a second-stage pressure leaching stage. According to the method, by matching the high-copper material, adding proper sulfuric acid and oxygen and controlling the kettle temperature, the kettle pressure and the pH value, the leaching rate of nickel is increased, a relatively pure nickel sulfate solution is obtained, the open circuit problem of high iron and high sulfur in a system is solved, generation of hydrogen sulfide gas is completely eradicated, and meanwhile, two-stage pressure leaching residues can be conveyed to a pyrogenic process system to be recycled.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for preparing a nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials. Background Art

[0002] Nickel sulfate is mainly used in the surface treatment industry and the power battery industry. It is the main nickel salt for electroplating nickel and chemical nickel plating, and is also the main raw material for manufacturing power batteries. The existing technology uses the following method to prepare nickel sulfate: add a sulfiding agent to the laterite ore to obtain high-nickel matte, and then obtain nickel sulfate through a pressure leaching process. This method mainly has the following two problems: First, the reaction of the sulfidation and water quenching process is incomplete, and some alloy phases will be mixed; second, the copper content in the high-nickel matte is low and the proportion of alloy phase is high. Hydrogen sulfide gas is easily generated during pressurized leaching, and it is also easy to cause blockage of solution delivery pipelines, valves, and pump facilities. Therefore, there is an urgent need to further study and improve the method of preparing nickel sulfate solution from high-nickel, low-copper, high-iron, and high-sulfur materials. Summary of the invention

[0003] In view of the above problems, the present invention provides a method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials, which solves the open circuit problem of high iron and high sulfur in the system and eliminates the generation of hydrogen sulfide gas.

[0004] To achieve the above object, the technical solution of the present invention is as follows:

[0005] A method for preparing a nickel sulfate solution from a high-nickel, low-copper, high-iron, and high-sulfur material comprises the following steps:

[0006] 1) A normal pressure slurry batching stage: adding high copper and high nickel matte material to high nickel, low copper, high iron and high sulfur material, adding a pressurized leaching solution, and obtaining a normal pressure slurry nickel sulfide high nickel matte slurry; wherein the chemical composition of the high nickel, low copper, high iron and high sulfur material includes: 68-70% nickel, 0.5-0.7% copper, 3-5% iron, 23-26% sulfur, nickel mainly exists in the form of 75-77% Ni3S2 and 23-25% alloy phase, and the main chemical composition of the high copper nickel sulfide high nickel matte material is: 65-67% nickel, 4.8-5.5% copper, and 3-5% iron;

[0007] 2) A normal pressure leaching stage: the slurry is leached at normal pressure, and then sent to a thickener for concentration and separation to obtain a supernatant and an underflow, and the supernatant is filtered through a filter press to obtain a nickel sulfate solution;

[0008] 3) Second stage normal pressure leaching stage: adding the second stage pressurized leaching liquid to the underflow obtained in the first stage normal pressure leaching stage to obtain the second stage normal pressure slurry liquid, and performing normal pressure leaching to obtain the second stage normal pressure leaching liquid;

[0009] 4) One-stage pressure leaching stage: the two-stage normal pressure leaching solution is subjected to pressure leaching, and then sent to a thickener for separation to obtain overflow liquid and underflow, and the overflow liquid is the first-stage pressure leaching solution;

[0010] 5) Second stage pressure leaching stage: sulfuric acid and water are added to the underflow generated in step 4) for second stage pressure leaching, and the leaching liquid is sent to a filter press, and the filtrate is the second stage pressure leaching liquid.

[0011] Preferably, in step 1), the chemical composition of the high-nickel, low-copper, high-iron and high-sulfur material also includes: 0.4-0.7% cobalt, 0.002-0.005% zinc, 0.01-0.04% lead, and 0.002-0.006% arsenic; the copper-iron ratio of the high-nickel, low-copper, high-iron and high-sulfur material and the high-copper nickel sulfide high-nickel matte material after mixing is 1.5-2.5:1, and the nickel taste is >60%; the concentration of the nickel sulfide high-nickel matte slurry after normal pressure slurrying is 25%-35%.

[0012] Preferably, in step 3), the liquid-to-solid ratio of the second-stage atmospheric pressure slurry is 7-11:1.

[0013] Preferably, in step 2), the endpoint pH of the atmospheric pressure leaching is 5.0-6.0, and the leaching temperature is 70-90°C; the nickel sulfate solution contains ≥100 g / L nickel, ≤3 g / L copper, and ≤1 g / L iron.

[0014] Preferably, in step 3), the pH value of the second-stage normal pressure slurry is 0.5-1, the pH value of the second-stage leaching endpoint is 1.5-3.0, and the leaching temperature is 70-90°C; the copper content of the second-stage normal pressure slurry is ≥3g / L.

[0015] Preferably, in step 4), the leaching pressure is 0.5-0.9 MPa, the reaction temperature is 140-190° C., the leaching endpoint pH is 2.0-3.5, the leaching time is 4.0-5.0 h, and the oxygen partial pressure is 0.15-0.50 MPa; the composition of the pressurized leaching solution is 100-140 g / L nickel, ≤30 g / L copper, and ≤5 g / L iron.

[0016] Preferably, in step 5), the leaching pressure is 0.4-0.7 MPa, the reaction temperature is 100-170° C., the leaching endpoint pH is 1.0-3.0, the leaching time is 4.5-5.5 h, and the oxygen partial pressure is 0.10-0.40 MPa.

[0017] In the first stage of atmospheric leaching, the first stage of pressurized leaching solution is an acid solution containing copper and iron. The copper is removed by dissolving and replacing the alloy phase in the raw material. As the pH increases, the copper will be precipitated in the slag in the form of basic salt. Under the condition of compressed air, the divalent iron in the solution is oxidized and hydrolyzed to precipitate, thereby producing a relatively pure nickel sulfate solution. The reaction formula is as follows:

[0018] Ni+2CuSO4+1 / 2O=2NiSO4+Cu2O (1)

[0019] Ni+H2SO4+1 / 2O2=NiSO4+H2O (2)

[0020] Cu2O+2H2SO4+1 / 2O2=2CuSO4+2H2O (3)

[0021] 3CuSO4+4H2O=CuSO4·2Cu(OH)2↓+2H2SO4 (4)

[0022] 2FeSO4+1 / 2O2+H2SO4=Fe2(SO4)3+H2O (5)

[0023] Fe2(SO4)3+6H2O=2Fe(OH)3↓+3H2SO4 (6)

[0024] In the second stage of atmospheric pressure leaching, qualified ore pulp is provided to the first stage of pressure leaching. Due to the high acidity of the second stage atmospheric pressure leaching process, FeS and part of NiS and CoS in the material react with sulfuric acid to produce hydrogen sulfide gas; however, copper sulfide is extremely insoluble in water, and its Ksp at 25°C is 1.27×10 -36 Therefore, as long as the solution contains a certain amount of copper ions, hydrogen sulfide will be suppressed before overflowing. The main reaction formula is as follows:

[0025] MeS+H2SO4=MeSO4+H2S↑ (7)

[0026] H2S+CuSO4=CuS↓+H2SO4 (8)

[0027] The purpose of pressure leaching is to achieve the highest possible leaching rate of nickel. At the same time, the leached copper is used for the atmospheric pressure leaching process, and most of the copper and precious metals in various high-nickel matte raw materials are suppressed in the leaching slag. The sulfur is converted into sulfate ions or copper sulfide precipitation to achieve the open circuit of iron and sulfur. The main reaction formula is as follows:

[0028] NiS+2O2=NiSO4 (9)

[0029] 2FeSO4+1 / 2O2+H2SO4=Fe2(SO4)3+H2O (10)

[0030] Fe2(SO4)3+(3+x)H2O=Fe2O3·(H2O) x ↓+3H2SO4 (11)

[0031] 6NiS+2CuSO4+4H2O=Cu2S↓+6NiSO4+2H2SO4 (12)

[0032] Cu2S+H2SO4+1 / 2O2=CuS↓+CuSO4+H2O (13)

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention provides a method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials. The method improves the leaching rate of nickel by matching high-copper materials, adding appropriate sulfuric acid and oxygen, and controlling the kettle temperature, kettle pressure and pH value, thereby obtaining a relatively pure nickel sulfate solution, solving the open circuit problem of high iron and high sulfur in the system, and preventing the generation of hydrogen sulfide gas. At the same time, the two-stage pressurized leaching slag can also be sent to the pyrometallurgical system for recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Process flow chart of the present invention. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0037] A method for preparing a nickel sulfate solution from a high-nickel, low-copper, high-iron, and high-sulfur material comprises the following steps:

[0038] 1) A normal pressure slurry batching stage: adding high copper nickel sulfide high nickel matte material to high nickel, low copper, high iron and high sulfur material, adding a pressurized leaching solution, to obtain a normal pressure slurry nickel sulfide high nickel matte slurry;

[0039] 2) A normal pressure leaching stage: the slurry is leached at normal pressure, and then sent to a thickener for concentration and separation to obtain a supernatant and an underflow, and the supernatant is filtered through a filter press to obtain a nickel sulfate solution;

[0040] 3) Second stage normal pressure leaching stage: adding the second stage pressurized leaching liquid to the underflow obtained in the first stage normal pressure leaching stage to obtain the second stage normal pressure slurry liquid, and performing normal pressure leaching to obtain the second stage normal pressure leaching liquid;

[0041] 4) One-stage pressure leaching stage: the two-stage normal pressure leaching solution is subjected to pressure leaching, and then sent to a thickener for separation to obtain overflow liquid and underflow, and the overflow liquid is the first-stage pressure leaching solution;

[0042] 5) Second stage pressure leaching stage: sulfuric acid and water are added to the underflow generated in step 4) for second stage pressure leaching, and the leaching liquid is sent to a filter press, and the filtrate is the second stage pressure leaching liquid.

[0043] Example 1

[0044] A method for preparing a nickel sulfate solution from a high-nickel, low-copper, high-iron, and high-sulfur material comprises the following steps:

[0045] 1) One-stage atmospheric pressure slurry batching stage: take a typical composition: high-nickel, low-copper, high-iron, high-sulfur material containing 69.45% nickel, 0.59% copper, 3.34% iron, 0.54% cobalt, and 24.25% sulfur, and match it with purchased nickel sulfide and high-nickel matte. The chemical composition of the mixed raw material is 60.06% nickel, 5.84% copper, 3.86% iron, 1.06% cobalt, and 26.54% sulfur. The nickel grade of the mixed raw material is increased to 60.06%. The ore is mixed with the first-stage pressurized leaching solution to prepare a first-stage atmospheric pressure slurry with a concentration of 25%; among which the alloy phase Ni: 1.06%; Ni3S2: 3.51%.

[0046] 2) Normal pressure leaching stage: the slurry is sent to the normal pressure reaction tank for normal pressure leaching. The reaction tank temperature is 70℃ and compressed air is introduced at 1200Nm 3 / (h·tank), after leaching, the leaching mixture is sent to a thickener for concentration and separation to obtain a supernatant and an underflow, and then the supernatant is filtered through a filter press to obtain a nickel sulfate solution; the nickel sulfate solution contains nickel ≥100g / L; copper ≤3g / L; iron ≤1g / L, and the specific ingredients are: nickel 116.243g / L; copper 0.0061g / L; iron 0.012g / L; cobalt 1.26g / L; lead 0.011g / L; zinc 0.15g / L; arsenic 0.00031g / L; pH value is 5.0.

[0047] 3) Second stage normal pressure leaching stage: The second stage pressurized leaching liquid is added to the bottom flow in step 2) to prepare a second stage normal pressure slurry liquid with a liquid-solid ratio of 7:1 and a pH value of 0.5 after slurrying. The second stage normal pressure slurry liquid contains copper: 10.34g / L, and is sent to a normal pressure reaction tank for normal pressure leaching. The temperature of the reaction tank is 70°C, and compressed air is introduced at 1000Nm 3 / (h·tank), after leaching, it is sent to the pressure kettle for pressure leaching;

[0048] 4) One-stage pressure leaching stage: the two-stage normal pressure leaching slurry is subjected to pressure leaching, the pressure leaching temperature is controlled to be 140°C, the kettle pressure is 0.5MPa, the oxygen partial pressure is 0.15MPa, the reaction is 4h, the first-stage pressure leaching liquid contains 116.75g / L nickel, 16.68g / L copper, and 1.68g / L iron. After cooling and reducing pressure in the flash tank, it is sent to the thickener for concentration and separation to obtain a supernatant and an underflow. The supernatant is then filtered through a filter press to obtain a first-stage pressure leaching liquid, which is pumped to a first-stage normal pressure slurry tank through a pipeline for slurry batching, and the underflow is respectively transported to the second-stage pressure leaching;

[0049] 5) Secondary pressure leaching stage: sulfuric acid and water are added to the underflow generated in step 4) for secondary pressure leaching, the pressure leaching temperature is controlled to be 100° C., the kettle pressure is 0.4 MPa, the oxygen partial pressure is 0.1 MPa, the reaction is carried out for 4.5 hours, the leached slurry is cooled and decompressed by a secondary flash tank, and is transported to a diaphragm filter press through a pipeline for filtration, and the filtrate is transported to the secondary normal pressure batching, and the filter residue is externally supplied to the pyrometallurgical system.

[0050] Example 2

[0051] A method for preparing a nickel sulfate solution from a high-nickel, low-copper, high-iron, and high-sulfur material comprises the following steps:

[0052] 1) One-stage atmospheric pressure slurry batching stage: Take a typical composition: high-nickel, low-copper, high-iron, high-sulfur material containing 68.26% nickel, 0.52% copper, 3.23% iron, 0.44% cobalt, and 25.3% sulfur, and match it with purchased nickel sulfide and high-nickel matte. The chemical composition of the mixed raw material is 66.12% nickel, 5.14% copper, 3.32% iron, 0.87% cobalt, and 24.54% sulfur. The nickel grade of the mixed raw material is increased to 66.12%. The ore is mixed with the first-stage pressurized leaching solution to prepare a first-stage atmospheric pressure slurry with a concentration of 35%.

[0053] 2) Normal pressure leaching stage: the slurry is sent to the normal pressure reaction tank for normal pressure leaching. The reaction tank temperature is 90℃ and compressed air is introduced at 1200Nm 3 / (h·tank), after leaching, the leaching mixture is sent to a thickener for concentration and separation to obtain a supernatant and an underflow, and then the supernatant is filtered through a filter press to obtain a nickel sulfate solution; the nickel sulfate solution contains nickel ≥100g / L; copper ≤3g / L; iron ≤1g / L, and the specific ingredients are: nickel 105.43g / L; copper 0.0042g / L; iron 0.0034g / L; cobalt 1.46g / L; lead 0.043g / L; zinc 0.3g / L; arsenic 0.00037g / L; pH value is 6.0.

[0054] 3) Second stage normal pressure leaching stage: The second stage pressurized leaching liquid is added to the bottom flow in step 2) to prepare a second stage normal pressure slurry liquid with a liquid-solid ratio of 11:1 and a pH value of 1 after slurrying. The second stage normal pressure slurry liquid contains copper: 21.46g / L, and is sent to a normal pressure reaction tank for normal pressure leaching. The temperature of the reaction tank is 90°C, and compressed air is introduced at 1000Nm 3 / (h·tank), after leaching, it is sent to the pressure kettle for pressure leaching;

[0055] 4) One-stage pressure leaching stage: the slurry from the second-stage atmospheric pressure leaching is subjected to pressure leaching, and the pressure leaching temperature is controlled to be 190°C, the kettle pressure is 0.9MPa, the oxygen partial pressure is 0.50MPa, and the reaction is carried out for 5h. The composition of the first-stage pressure leaching liquid is 107.06g / L nickel, 18.04g / L copper, and 2.23g / L iron. After being cooled and depressurized in a flash evaporator, it is sent to a thickener for concentration and separation to obtain a supernatant and an underflow. The supernatant is then filtered through a filter press to obtain a first-stage pressure leaching liquid, which is pumped to a first-stage atmospheric pressure slurry tank through a pipeline for slurry batching, and the underflow is respectively transported to the second-stage pressure leaching;

[0056] 5) Secondary pressure leaching stage: sulfuric acid and water are added to the underflow generated in step 4) for secondary pressure leaching, the pressure leaching temperature is controlled to be 170° C., the kettle pressure is 0.7 MPa, the oxygen partial pressure is 0.4 MPa, the reaction is performed for 5.5 hours, the leached slurry is cooled and decompressed by a secondary flash tank, and is transported to a membrane filter press through a pipeline for filtration, and the filtrate is transported to the secondary normal pressure batching, and the filter residue is externally supplied to the pyrometallurgical system.

[0057] The present invention provides a method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials. The method improves the leaching rate of nickel by matching high-copper materials, adding appropriate sulfuric acid and oxygen, and controlling the kettle temperature, kettle pressure and pH value, thereby obtaining a relatively pure nickel sulfate solution, solving the open circuit problem of high iron and high sulfur in the system, and preventing the generation of hydrogen sulfide gas. At the same time, the two-stage pressurized leaching slag can also be sent to the pyrometallurgical system for recovery.

Claims

1. A method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials, characterized in that: The following steps are involved: 1) A normal pressure slurry batching stage: adding high copper nickel sulfide high nickel matte material to high nickel, low copper, high iron and high sulfur material, adding a pressurized leaching solution, and obtaining a normal pressure slurry nickel sulfide high nickel matte slurry; wherein the chemical composition of the high nickel, low copper, high iron and high sulfur material includes: 68-70% nickel, 0.5-0.7% copper, 3-5% iron, 23-26% sulfur, and nickel mainly exists in the form of 75-77% Ni3S2 and 23-25% alloy phase; the chemical composition of the high copper nickel sulfide high nickel matte material includes: 65-67% nickel, 4.8-6.0% copper, and 3-5% iron; 2) A normal pressure leaching stage: the slurry is leached at normal pressure, and then sent to a thickener for concentration and separation to obtain a supernatant and an underflow, and the supernatant is filtered through a filter press to obtain a nickel sulfate solution; 3) Second stage normal pressure leaching stage: adding the second stage pressurized leaching liquid to the underflow obtained in the first stage normal pressure leaching stage to obtain the second stage normal pressure slurry liquid, and performing normal pressure leaching to obtain the second stage normal pressure leaching liquid; 4) One-stage pressure leaching stage: the two-stage normal pressure leaching solution is subjected to pressure leaching, and then sent to a thickener for separation to obtain overflow liquid and underflow, and the overflow liquid is the first-stage pressure leaching solution; 5) Second stage pressure leaching stage: sulfuric acid and water are added to the underflow generated in step 4) for second stage pressure leaching, and the leaching liquid is sent to a filter press, and the filtrate is the second stage pressure leaching liquid.

2. The method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials according to claim 1, characterized in that: In step 1), the chemical composition of the high-nickel, low-copper, high-iron and high-sulfur material also includes: 0.4-0.7% cobalt, 0.002-0.005% zinc, 0.01-0.04% lead, and 0.002-0.006% arsenic; the copper-iron ratio of the high-nickel, low-copper, high-iron and high-sulfur material and the high-copper nickel sulfide high-nickel matte material after mixing is 1.5-2.5:1, and the nickel taste is >60%; the concentration of the nickel sulfide high-nickel matte slurry after normal pressure slurrying is 25%-35%.

3. The method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials according to claim 1, characterized in that: In step 3), the liquid-to-solid ratio of the second-stage atmospheric pressure slurry is 7-11:

1.

4. A method for preparing nickel sulfate solution from a high-nickel, low-copper, high-iron, high-sulfur material as claimed in claim 1 or 3, characterized in that: In step 2), the endpoint pH of the atmospheric pressure leaching is 5.0-6.0, and the leaching temperature is 70-90° C.; the nickel sulfate solution contains ≥100 g / L nickel, ≤3 g / L copper, and ≤1 g / L iron.

5. The method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials according to claim 1, characterized in that: In step 3), the pH value of the second-stage normal pressure slurry is 0.5-1, the pH value of the second-stage leaching end point is 1.5-3.0, and the leaching temperature is 70-90° C.; the copper content of the second-stage normal pressure slurry is ≥3 g / L.

6. The method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials according to claim 1, characterized in that: In step 4), the leaching pressure is 0.5-0.9 MPa, the reaction temperature is 140-190° C., the leaching endpoint pH value is 2.0-3.5, the leaching time is 4.0-5.0 h, and the oxygen partial pressure is 0.15-0.50 MPa; the composition of the pressurized leaching solution is 100-140 g / L nickel, ≤30 g / L copper, and ≤5 g / L iron.

7. The method for preparing nickel sulfate solution from high-nickel, low-copper, high-iron and high-sulfur materials according to claim 1, characterized in that: In step 5), the leaching pressure is 0.4-0.7 MPa, the reaction temperature is 100-170° C., the leaching end point pH value is 1.0-3.0, the leaching time is 4.5-5.5 h, and the oxygen partial pressure is 0.10-0.40 MPa.

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