A preparation method of nickel sulfate and its application

Abstract

A method for preparing nickel sulfate and its application belong to the technical field of nickel sulfate preparation. The method comprises: reacting carbon dioxide with a nickel-iron alloy to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide; reacting the mixed solid with sulfuric acid to obtain a first mixed solution containing nickel sulfate and ferrous sulfate, and then removing the ferrous sulfate to obtain nickel sulfate. This method avoids the problem of flammable and explosive hydrogen gas generated during the traditional process of preparing nickel sulfate by acid leaching of nickel-iron alloy, thereby improving process safety. The nickel sulfate thus obtained can be further used to prepare nickel cobalt manganese oxide battery precursors.

Description

Technical Field

[0001] The present disclosure relates to the technical field of nickel sulfate preparation, and in particular to a method for preparing nickel sulfate and applications thereof. Background Art

[0002] Nickel sulfate is a crucial upstream material in the electroplating and battery industries. In the battery industry, nickel sulfate is a crucial raw material with irreplaceable value. With the rapid development of the new energy industry, nickel resources are attracting increasing attention. Nickel sulfate is primarily used as a precursor for the production of lithium nickel cobalt manganese oxide battery materials. With the rapid development of new energy vehicles, nickel sulfate consumption is increasing annually. In modern industry, nickel sulfate is produced from nickel-iron alloys using two main process routes: pyrometallurgical and hydrometallurgical. Compared to pyrometallurgical nickel extraction from nickel-iron alloys, hydrometallurgical nickel extraction offers advantages such as lower energy consumption, simpler processes, simpler equipment, and lower investment costs. However, current hydrometallurgical processes generally involve direct acid addition to produce a wet leachate containing nickel sulfate and ferrous sulfate. The reaction equations involved are: Ni + H2SO4 = NiSO4 + H2; Fe + H2SO4 = FeSO4 + H2. This process generates flammable and explosive hydrogen, posing a significant threat to operational safety.

[0003] In view of this, the present disclosure is proposed. Summary of the Invention

[0004] The purpose of the present disclosure includes providing a preparation method of nickel sulfate and its application, which can solve or improve the above-mentioned technical problems.

[0005] The present disclosure can be implemented as follows:

[0006] In a first aspect, the present disclosure provides a method for preparing nickel sulfate, comprising the following steps: reacting carbon dioxide with a nickel-iron alloy to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide;

[0007] The mixed solid is reacted with sulfuric acid to obtain a first mixed solution containing nickel sulfate and ferrous sulfate, and then the ferrous sulfate is removed to obtain nickel sulfate.

[0008] In an optional embodiment, the carbon dioxide comes from the tail gas of sintering of the positive electrode material of the battery.

[0009] In an optional embodiment, the battery positive electrode material includes a ternary positive electrode material.

[0010] In an optional embodiment, the precursor of the ternary positive electrode material is in the form of a carbonate or a hydroxide; when the precursor of the ternary positive electrode material is in the form of a hydroxide, a carbon-containing substance is added during the sintering stage during the preparation of the ternary positive electrode material.

[0011] In an alternative embodiment, the carbonaceous material is lithium carbonate.

[0012] In an optional embodiment, the reaction of carbon dioxide with nickel-iron alloy has at least one of the following characteristics:

[0013] Feature 1: Reaction temperature is not less than 1000℃;

[0014] Feature 2: Reaction time is 40min-80min;

[0015] Feature 3: The volume fraction of carbon dioxide in the reaction vessel is ≥50%;

[0016] Feature 4: The reaction is carried out in a reducing atmosphere.

[0017] In an optional embodiment, carbon dioxide in the sintering tail gas of the battery positive electrode material is enriched to obtain an enriched material; the enriched material is heated to release the enriched carbon dioxide and the released carbon dioxide is introduced into a reaction vessel containing nickel-iron alloy.

[0018] In an optional embodiment, the enrichment includes: chemically absorbing carbon dioxide in the tail gas from the sintering of the battery positive electrode material using a weak alkaline absorbent.

[0019] In an optional embodiment, the weakly alkaline absorbent includes at least one of an organic amine, aqueous ammonia, and a carbonate.

[0020] In an alternative embodiment, the enrichment is performed at 38°C-42°C, and / or the heating is performed at 120°C-125°C.

[0021] In an optional embodiment, the reaction of the mixed solid with sulfuric acid has at least one of the following characteristics:

[0022] Feature 1: Reaction temperature is 25℃-40℃;

[0023] Feature 2: Reaction time is 5h-15h;

[0024] Feature 3: The amount of sulfuric acid added is not less than 1.2 times the theoretical amount of nickel and iron in the nickel-iron alloy.

[0025] In an alternative embodiment, the sulfuric acid is concentrated sulfuric acid.

[0026] In an optional embodiment, removing ferrous sulfate includes: mixing the first mixed solution with an oxidant to make Fe 2+ Oxidized to Fe 3+ , obtain a second mixed solution; mix the second mixed solution with ion exchange resin to make Fe 3+ Adsorbed on ion exchange resin, solid-liquid separation, and liquid collection.

[0027] In an optional embodiment, the amount of oxidant is not less than Fe 2+ Oxidized to Fe 3+ 1.2 times the theoretical consumption; and / or, the amount of ion exchange resin is not less than Fe in the second mixed solution 3+ 1.2 times the content.

[0028] In an optional embodiment, the oxidant is hydrogen peroxide, and / or the ion exchange resin is a sulfonic acid phosphate chelating ion exchange resin.

[0029] In an optional embodiment, the removal of ferrous sulfate is carried out at a temperature of 35° C.-45° C. and a redox potential of 550 mV-650 mV.

[0030] In an optional embodiment, the ion exchange resin is washed with water before solid-liquid separation.

[0031] In an optional embodiment, the mixed gas containing carbon monoxide is recycled.

[0032] In an optional embodiment, when the volume ratio of carbon monoxide to carbon dioxide in the carbon monoxide-containing mixed gas is (1:0.05)-(1:1), the carbon monoxide-containing mixed gas is ignited in air to be used as fuel.

[0033] In a second aspect, the present disclosure also provides the use of nickel sulfate prepared by the above preparation method in the preparation of lithium nickel cobalt manganese oxide battery precursors.

[0034] The present disclosure creatively proposes to use carbon dioxide and nickel-iron alloy to react to prepare nickel sulfate. This method can not only effectively avoid the problem of hydrogen generation and improve process safety, but also make rational use of waste carbon dioxide, and has the characteristics of low carbon emission reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 This is a process flow chart for preparing nickel sulfate in Example 1 of the present disclosure. DETAILED DESCRIPTION

[0037] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer were followed. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0038] The preparation method and application of nickel sulfate provided by the present disclosure are described in detail below.

[0039] Based on the problem that flammable and explosive hydrogen will be produced during the preparation of nickel sulfate by acid leaching of nickel-iron alloys in the current traditional route, the inventors have creatively proposed to use carbon dioxide to prepare nickel sulfate. This method can not only effectively avoid the problem of hydrogen production and improve process safety, but also make rational use of carbon dioxide, with the characteristics of low carbon emission reduction.

[0040] For reference, the method for preparing nickel sulfate proposed in the present disclosure may include the following steps: reacting carbon dioxide with nickel-iron alloy to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide.

[0041] The mixed solid is reacted with sulfuric acid to obtain a first mixed solution containing nickel sulfate and ferrous sulfate, and then the ferrous sulfate is removed to obtain nickel sulfate.

[0042] In some embodiments, the carbon dioxide used to react with the nickel-iron alloy is derived from the tail gas of the sintering of the battery positive electrode material.

[0043] It should be noted that the current production process of lithium-ion battery positive electrode materials mainly adopts the synthesis of lithium source and precursor by sintering at high temperature. According to statistics from the Guangdong Provincial Key Laboratory of Battery Recycling, carbon emissions for each ton of positive electrode material produced are about 5 to 8 tCO2e, of which the carbon emissions in the sintering stage are the largest in the entire positive electrode material production process, accounting for about 50%. Most of the carbon dioxide in the above-mentioned sintering stage is directly discharged, resulting in a rapid increase in the carbon dioxide content in the atmosphere. The present disclosure can reasonably recycle and utilize waste resources by recovering this part of the tail gas and using it to prepare nickel sulfate, saving energy and reducing emissions, and being low-carbon and environmentally friendly.

[0044] In other embodiments, the carbon dioxide used to react with the nickel-iron alloy may also be derived from other sources, which are not limited herein.

[0045] For reference, the above-mentioned battery positive electrode material may include, for example, a ternary positive electrode material, a binary positive electrode material, or a quaternary positive electrode material, etc. Among them, the ternary positive electrode material may be a nickel-cobalt-manganese ternary positive electrode material.

[0046] In some embodiments, the precursor of the ternary cathode material is in the form of a carbonate; in other embodiments, the precursor of the ternary cathode material is in the form of a hydroxide. When the precursor of the ternary cathode material is in the form of a hydroxide, a carbon-containing material, such as lithium carbonate, may be added during the sintering stage during the preparation of the ternary cathode material. It should be noted that when the precursor is in the form of a carbonate, the carbon-containing material can also be added during the sintering stage.

[0047] For example, the tail gas from the sintering of the battery positive electrode material may include carbon dioxide tail gas generated at any sintering stage. In the present disclosure, the reaction of carbon dioxide with the nickel-iron alloy is carried out in a reducing atmosphere at a temperature not lower than 1000°C, for example, 1000°C, 1100°C, 1200°C, 1300°C, or 1400°C.

[0048] Under the above temperature conditions, carbon dioxide can react with nickel-iron alloy, and the corresponding reaction equations include: CO2+Ni=NiO+CO; CO2+Fe=FeO+CO.

[0049] If the temperature is lower than 1000°C, carbon dioxide and nickel-iron alloy cannot react effectively or even cannot react at all.

[0050] The reaction time of carbon dioxide and nickel-iron alloy can be 40 min-80 min, such as 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min or 80 min, or any other value within the range of 40 min-80 min.

[0051] The volume fraction of carbon dioxide in the reaction container is ≥50%, such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%.

[0052] If the volume fraction of carbon dioxide in the reaction vessel is too low, the nickel-iron alloy cannot be completely reacted.

[0053] For reference, the carbon dioxide and the nickel-iron alloy can be reacted in a kiln (such as a rotary kiln). In addition, the carbon dioxide and the nickel-iron alloy can also be reacted in other reaction vessels according to actual conditions, which are not listed here.

[0054] In some optional embodiments, the carbon dioxide in the sintering tail gas of the battery positive electrode material can be first enriched to obtain an enriched material; the enriched material is heated to release the enriched carbon dioxide and the released carbon dioxide is introduced into a reaction vessel containing nickel-iron alloy.

[0055] For example, the enrichment process may include chemically absorbing carbon dioxide from the battery cathode material calcination exhaust gas using a weakly alkaline absorbent. The weakly alkaline absorbent may include, for example, at least one of an organic amine, ammonia, and a carbonate. The enrichment process may be performed at a temperature between 38°C and 42°C (e.g., 38°C, 39°C, 40°C, 41°C, or 42°C).

[0056] For example, the enriched material may be heated at 120° C. to 125° C. (e.g., 120° C., 121° C., 122° C., 123° C., 124° C., or 125° C.) Under these temperature conditions, the enriched material undergoes a reversible reaction to release enriched carbon dioxide.

[0057] Furthermore, after the carbon dioxide reacts with the nickel-iron alloy, the obtained mixed solid is reacted with sulfuric acid to obtain a first mixed solution containing nickel sulfate and ferrous sulfate.

[0058] For reference, the temperature for reacting the mixed solid with sulfuric acid can be 25°C-40°C, such as 25°C, 28°C, 30°C, 32°C, 35°C, 38°C or 40°C. The reaction time can be 5h-15h, such as 5h, 8h, 10h, 12h or 15h. The amount of sulfuric acid added is not less than 1.2 times the theoretical amount of nickel and iron in the nickel-iron alloy, such as 1.2 times, 1.3 times or 1.4 times. The sulfuric acid can be concentrated sulfuric acid, for example, 98% concentrated sulfuric acid.

[0059] The reaction equations involved in the reaction of the above-mentioned mixed solid with sulfuric acid include: NiO+H2SO4=NiSO4+H2O; FeO+H2SO4=FeSO4+H2O.

[0060] For reference, removing ferrous sulfate from the first mixed solution may include the following steps: mixing the first mixed solution with an oxidizing agent to make Fe 2+ Oxidized to Fe 3+ , obtain a second mixed solution; mix the second mixed solution with ion exchange resin to make Fe 3+ Adsorbed on ion exchange resin, solid-liquid separation, and liquid collection.

[0061] Among them, the amount (mass) of the oxidant is not less than Fe 2+ Oxidized to Fe 3+ 1.2 times of the theoretical consumption of the oxidant, such as 1.2 times, 1.3 times or 1.4 times, etc. The oxidant can be, for example but not limited to, hydrogen peroxide, and the concentration of hydrogen peroxide can be 27%.

[0062] The amount (mass) of ion exchange resin used may not be less than the Fe 3+The ion exchange resin can be 1.2 times, 1.3 times or 1.4 times the content of Fe, such as 1.2 times, 1.3 times or 1.4 times. The ion exchange resin can be exemplarily but not limited to a sulfonic acid phosphate chelate ion exchange resin. The ion exchange resin adsorbs Fe 3+ After the reaction, the remaining nickel sulfate remains in the solution. The iron can be removed by solid-liquid separation to obtain a nickel sulfate solution.

[0063] The above-mentioned removal of ferrous sulfate can be carried out at a temperature of 35°C-45°C (such as 35°C, 38°C, 40°C, 42°C or 45°C, etc.) and a redox potential of 550mV-650mV (such as 550mV, 580mV, 600mV, 620mV or 650mV, etc.).

[0064] By setting the redox potential condition within the above range, it is possible to effectively prevent the oxidized iron ions from turning back into ferrous ions.

[0065] In some embodiments, before solid-liquid separation, the ion exchange resin can be washed with water to flush away the nickel sulfate solution attached to the surface of the ion exchange resin and reduce the loss rate of nickel sulfate. For example, the flow rate of water used for washing can be 4 BV / h to 6 BV / h, such as 4 BV / h, 4.5 BV / h, 5 BV / h, 5.5 BV / h, or 6 BV / h, and the washing time can be 0.2 h to 0.8 h, such as 0.2 h, 0.4 h, 0.6 h, or 0.8 h.

[0066] The nickel sulfate prepared by the above method can be used to prepare nickel cobalt manganese oxide lithium battery precursor.

[0067] In the present disclosure, the mixed gas containing carbon monoxide generated by the reaction of carbon dioxide and nickel-iron alloy can also be recycled and utilized.

[0068] For example, when the volume ratio of carbon monoxide to carbon dioxide in the carbon monoxide-containing mixed gas is (1:0.05)-(1:1), the carbon monoxide-containing mixed gas can be ignited in air to be used as fuel.

[0069] The features and performance of the present disclosure are further described in detail below with reference to the embodiments.

[0070] Example 1

[0071] This embodiment provides a method for preparing nickel sulfate, referring to Figure 1 , which includes the following steps:

[0072] S1: Ammonia is used to absorb the carbon dioxide-containing tail gas generated during the sintering process of 1 ton of nickel-cobalt-manganese ternary cathode material to obtain a carbon dioxide-enriched material. The temperature of the enrichment process is 40°C.

[0073] Among them, the ammonia water is industrial ammonia water with a mass fraction of 25%, and the amount (mass) relationship of ammonia water to the amount of carbon dioxide in the tail gas is 2:1. The raw materials of the nickel-cobalt-manganese ternary positive electrode material are lithium salt in the form of carbonate and nickel-cobalt-manganese hydroxide precursor. Correspondingly, the preparation process of the nickel-cobalt-manganese ternary positive electrode material is as follows: the nickel-cobalt-manganese hydroxide precursor is mixed with lithium carbonate, wherein the amount of nickel-cobalt-manganese hydroxide precursor is 1012 kg; the amount of lithium carbonate is 410 kg, sintered and granulated in an air atmosphere to prepare lithium nickel cobalt manganese oxide; wherein the sintering temperature is 1300 ° C, the sintering time is 60 min; the chemical formula of the nickel-cobalt-manganese hydroxide precursor is Ni 0.5 Co 0.2 Mn 0.3 (OH)2.

[0074] S2: heating the enriched material at 120° C. to release the enriched carbon dioxide.

[0075] S3: The carbon dioxide released by S2 is heated to 1100°C and then introduced into a rotary kiln containing 100g of nickel-iron alloy (Ni: 64.28%, Fe: 35.72%) at a flow rate of 20L / h. The carbon dioxide is continuously introduced until the volume of the carbon dioxide is 60% of the reaction chamber of the rotary kiln. The carbon dioxide and the nickel-iron alloy are reacted at 1100°C for 60 minutes to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide.

[0076] S4: The mixed solid was reacted with 98% concentrated sulfuric acid (the amount of sulfuric acid added was 1.2 times the theoretical amount of nickel and iron in the nickel-iron alloy) at 40° C. for 10 h to obtain a first mixed solution containing nickel sulfate and ferrous sulfate.

[0077] S5: The first mixed solution is mixed with 27% hydrogen peroxide (the amount of hydrogen peroxide is Fe 2+ Oxidized to Fe 3+ 1.2 times the theoretical consumption) to make the Fe in ferrous sulfate 2+ Oxidized to Fe 3+ , obtaining a second mixed solution; the second mixed solution and ion exchange resin (the ion exchange resin is a sulfonic acid phosphate chelating ion exchange resin, the amount of which is the second mixed solution of Fe 3+ 1.2 times the content) mixed to make Fe 3+ All of the ions were adsorbed on the ion exchange resin. Subsequently, the sulfonic acid phosphoric acid chelate ion exchange resin was rinsed with high-purity water at a flow rate of 5 BV / h for 0.5 h, filtered, and the filtrate was collected to obtain a nickel sulfate solution.

[0078] S5: Recover the mixed gas containing carbon monoxide obtained in S3, and when the volume ratio of carbon monoxide to carbon dioxide contained in the mixed gas reaches 1:0.5, ignite the mixed gas in the air to use as fuel.

[0079] Example 2

[0080] This embodiment provides a method for preparing nickel sulfate, which comprises the following steps:

[0081] S1: Using organic amine (monoethanolamine) to absorb the carbon dioxide-containing tail gas generated during the sintering process of the nickel-cobalt-manganese ternary cathode material to obtain a carbon dioxide-enriched material. The temperature of the enrichment process is 38°C.

[0082] The ratio of the amount (mass) of the organic amine to the nickel-cobalt-manganese ternary positive electrode material is 3.25:1. The raw materials of the nickel-cobalt-manganese ternary positive electrode material are lithium salt in the form of carbonate and nickel-cobalt-manganese hydroxide precursor. Correspondingly, the preparation process of the nickel-cobalt-manganese ternary positive electrode material is as follows: the nickel-cobalt-manganese hydroxide precursor is mixed with lithium carbonate, wherein the amount of the nickel-cobalt-manganese hydroxide precursor is 963.58 kg; the amount of lithium carbonate is 405.25 kg, sintered and granulated in an air atmosphere to prepare lithium nickel-cobalt-manganese oxide; wherein the sintering temperature is 1000°C, the sintering time is 60 min; the chemical formula of the nickel-cobalt-manganese hydroxide precursor is Ni 0.65 Co 0.1 Mn 0.25 (OH)2.

[0083] S2: heating the enriched material at 120° C. to release the enriched carbon dioxide.

[0084] S3: The carbon dioxide released by S2 is heated to 1000°C and then introduced into a rotary kiln containing 100g of nickel-iron alloy (Ni: 27.12%, Fe: 72.88%) at a flow rate of 20L / h. The carbon dioxide is continuously introduced until the volume of the carbon dioxide is 50% of the reaction chamber of the rotary kiln. The carbon dioxide and the nickel-iron alloy are reacted at 1000°C for 80 minutes to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide.

[0085] S4: The mixed solid was reacted with 98% concentrated sulfuric acid (the amount of sulfuric acid added was 1.25 times the theoretical amount of nickel and iron in the nickel-iron alloy) at 25° C. for 15 h to obtain a first mixed solution containing nickel sulfate and ferrous sulfate.

[0086] S5: The first mixed solution is mixed with 27% hydrogen peroxide (the amount of hydrogen peroxide is Fe 2+ Oxidized to Fe 3+ 1.25 times the theoretical consumption) to make the Fe in ferrous sulfate2+ Oxidized to Fe 3+ , to obtain a second mixed solution; the second mixed solution and ion exchange resin (the ion exchange resin is a sulfonic acid phosphate chelating ion exchange resin, the amount of which is the second mixed solution of Fe 3+ 1.3 times the content) mixed to make Fe 3+ All of the ions were adsorbed on the ion exchange resin. Subsequently, the sulfonic acid-phosphoric acid chelate ion exchange resin was rinsed with high-purity water at a flow rate of 4 BV / h for 0.8 h, filtered, and the filtrate was collected to obtain a nickel sulfate solution.

[0087] S5: Recover the mixed gas containing carbon monoxide obtained in S3, and when the volume ratio of carbon monoxide to carbon dioxide contained in the mixed gas reaches 1:0.05, ignite the mixed gas in the air to use as fuel.

[0088] Example 3

[0089] This embodiment provides a method for preparing nickel sulfate, which comprises the following steps:

[0090] S1: Carbonate (potassium carbonate) is used to absorb the carbon dioxide-containing tail gas generated during the sintering process of the nickel-cobalt-manganese ternary cathode material to obtain a carbon dioxide-enriched material. The temperature of the enrichment process is 42°C.

[0091] Among them, the relationship between the amount (mass) of carbonate and nickel-cobalt-manganese ternary positive electrode material is 2.5:1. The raw materials of nickel-cobalt-manganese ternary positive electrode material are lithium salt in the form of carbonate and nickel-cobalt-manganese hydroxide precursor. Correspondingly, the preparation process of nickel-cobalt-manganese ternary positive electrode material is as follows: nickel-cobalt-manganese hydroxide precursor is mixed with lithium carbonate, wherein the amount of nickel-cobalt-manganese hydroxide precursor is 2011.12 kg; the amount of lithium carbonate is 810.35 kg, sintered and granulated in an air atmosphere to prepare lithium nickel-cobalt-manganese oxide; wherein the sintering temperature is 1200 ° C, the sintering time is 80 min; the chemical formula of nickel-cobalt-manganese hydroxide precursor is Ni 0.55 Co 0.23 Mn 0.22 (OH)2.

[0092] S2: heating the enriched material at 125° C. to release the enriched carbon dioxide.

[0093] S3: The carbon dioxide released from S2 is heated to 1200°C and then introduced into a rotary kiln containing 100g of nickel-iron alloy (Ni: 80.1%, Fe: 19.9%) at a flow rate of 20L / h. The carbon dioxide is continuously introduced until the volume of the carbon dioxide is 70% of the reaction chamber of the rotary kiln. The carbon dioxide and the nickel-iron alloy are reacted at 1200°C for 40 minutes to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide.

[0094] S4: The mixed solid was reacted with 98% concentrated sulfuric acid (the amount of sulfuric acid added was 1.3 times the theoretical amount of nickel and iron in the nickel-iron alloy) at 35° C. for 5 h to obtain a first mixed solution containing nickel sulfate and ferrous sulfate.

[0095] S5: The first mixed solution is mixed with 27% hydrogen peroxide (the amount of hydrogen peroxide is Fe 2+ Oxidized to Fe 3+ 1.3 times the theoretical consumption) to make the Fe in ferrous sulfate 2+ Oxidized to Fe 3+ , obtain a second mixed solution; the second mixed solution and ion exchange resin (ion exchange resin is a macroporous strong acid cation exchange resin, the amount of which is the second mixed solution Fe 3+ 1.4 times the content) mixed to make Fe 3+ All of the ions were adsorbed on the ion exchange resin. Subsequently, the sulfonic acid phosphate chelate ion exchange resin was rinsed with high-purity water at a flow rate of 6 BV / h for 0.2 h, filtered, and the filtrate was collected to obtain a nickel sulfate solution.

[0096] S5: Recover the mixed gas containing carbon monoxide obtained in S3, and when the volume ratio of carbon monoxide and carbon dioxide contained in the mixed gas reaches 1:1, ignite the mixed gas in the air to use as fuel.

[0097] Example 4

[0098] The difference between this embodiment and embodiment 1 is that: in S1, the battery positive electrode material is a binary positive electrode material. The raw materials of the nickel-manganese binary positive electrode material are lithium salt in the form of lithium carbonate and nickel-manganese hydroxide precursor. Accordingly, the preparation process of the nickel-manganese binary positive electrode material is as follows: the nickel-manganese hydroxide precursor is mixed with lithium carbonate, wherein the amount of nickel-manganese hydroxide precursor is 1012 kg; the amount of lithium carbonate is 410 kg, sintered and granulated in an air atmosphere to prepare lithium nickel manganese oxide; wherein the sintering temperature is 1300 ° C, the sintering time is 60 min; the chemical formula of the nickel-manganese hydroxide precursor is Ni 0.7 Mn 0.3 (OH)2.

[0099] Example 5

[0100] The difference between this embodiment and embodiment 1 is that in S1, the battery positive electrode material is a quaternary positive electrode material.

[0101] The raw materials of the nickel-cobalt-manganese-zirconium quaternary positive electrode material are lithium salt in the form of lithium carbonate and nickel-cobalt-manganese-zirconium hydroxide precursor. Correspondingly, the preparation process of the nickel-cobalt-manganese-zirconium quaternary positive electrode material is as follows: the nickel-cobalt-manganese-zirconium hydroxide precursor is mixed with lithium carbonate, wherein the amount of nickel-cobalt-manganese-zirconium hydroxide precursor is 1012 kg; the amount of lithium carbonate is 410 kg, sintered and granulated in an air atmosphere to prepare nickel-cobalt-manganese-zirconate lithium; wherein the sintering temperature is 1300 ° C, the sintering time is 60 min; the chemical formula of the nickel-cobalt-manganese-zirconium hydroxide precursor is Ni 0.5 Co 0.2 Mn 0.25 Zr 0.05 (OH)2.

[0102] Comparative Example 1

[0103] The difference between this comparative example and Example 1 is that the volume fraction of carbon dioxide in the reaction container is 40%.

[0104] Comparative Example 2

[0105] The difference between this comparative example and Example 1 is that the reaction temperature of carbon dioxide and nickel-iron alloy is 800°C.

[0106] Comparative Example 3

[0107] The difference between this comparative example and Example 1 is that the reaction time of carbon dioxide and nickel-iron alloy is 20 minutes.

[0108] Test example

[0109] The nickel content and the corresponding nickel metal extraction rate in the nickel sulfate solutions prepared by the methods provided in Examples 1-5 and Comparative Examples 1-3 were measured, and the results are shown in Table 1.

[0110] Table 1 Measurement results

[0111]

[0112] As can be seen from Table 1, the method provided by the present disclosure can successfully prepare nickel sulfate of higher purity using nickel-iron alloy as raw material, and the process does not produce hydrogen, and the utilization rate of nickel is also high. The comparative example does not meet the reaction conditions of carbon dioxide and nickel-iron, and both produce hydrogen, and the nickel sulfate extraction efficiency is low.

[0113] Industrial Applicability

[0114] The present disclosure provides a new idea and method for preparing nickel sulfate. This method can not only effectively avoid the problem of flammable and explosive hydrogen generated during the traditional process of preparing nickel sulfate by acid leaching of nickel-iron alloy, thereby improving process safety, but also can rationally recycle and utilize waste carbon dioxide tail gas resources, greatly reducing preparation costs, saving energy and reducing emissions, and being low-carbon and environmentally friendly.

Claims

1. A method for preparing nickel sulfate, characterized in that: The method comprises the following steps: reacting carbon dioxide with nickel-iron alloy to generate a mixed solid containing nickel oxide and ferrous oxide and a mixed gas containing carbon monoxide; reacting the mixed solid with sulfuric acid to obtain a first mixed solution containing nickel sulfate and ferrous sulfate, and then removing the ferrous sulfate; The reaction temperature of carbon dioxide and nickel-iron alloy is not lower than 1000° C.; the reaction time is 40 min-80 min; the volume fraction of carbon dioxide in the reaction container is ≥50%; and the reaction is carried out in a reducing atmosphere.

2. The preparation method according to claim 1, characterized in that The carbon dioxide is derived from the tail gas of the sintering of the positive electrode material of the battery.

3. The preparation method according to claim 2, characterized in that The battery positive electrode material includes a ternary positive electrode material.

4. The preparation method according to claim 3, characterized in that The precursor of the ternary positive electrode material is in the form of carbonate or hydroxide. When the precursor of the ternary positive electrode material is in the form of hydroxide, carbon-containing substances are added during the sintering stage in the preparation process of the ternary positive electrode material.

5. The preparation method according to claim 4, characterized in that The carbon-containing substance is lithium carbonate.

6. The preparation method according to claim 2, characterized in that The carbon dioxide in the sintering tail gas of the battery positive electrode material is enriched to obtain an enriched material; the enriched material is heated to release the enriched carbon dioxide and the released carbon dioxide is introduced into a reaction container containing nickel-iron alloy.

7. The preparation method according to claim 6, characterized in that The enrichment includes: using a weak alkaline absorbent to chemically absorb the carbon dioxide in the tail gas of the sintering of the battery positive electrode material.

8. The preparation method according to claim 7, characterized in that The weak alkaline absorbent includes at least one of organic amine, ammonia water and carbonate.

9. The preparation method according to claim 7, characterized in that The enrichment is carried out at 38°C-42°C, and / or the heating is carried out at 120°C-125°C.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The reaction of the mixed solid with sulfuric acid has at least one of the following characteristics: Feature 1: Reaction temperature is 25℃-40℃; Feature 2: Reaction time is 5h-15h; Feature 3: The amount of sulfuric acid added is not less than 1.2 times the theoretical amount of nickel and iron in the nickel-iron alloy.

11. The preparation method according to claim 10, characterized in that: The sulfuric acid is concentrated sulfuric acid.

12. The preparation method according to claim 1, characterized in that Removing ferrous sulfate includes: mixing the first mixed solution with an oxidant to make Fe 2+ Oxidized to Fe 3+ , obtain a second mixed solution; mixing the second mixed solution with an ion exchange resin to make Fe 3+ Adsorbed on ion exchange resin, solid-liquid separation, and liquid collection.

13. The preparation method according to claim 12, characterized in that The amount of the oxidant is not less than Fe 2+ Oxidized to Fe 3+ 1.2 times the theoretical consumption; and / or, the amount of the ion exchange resin is not less than the Fe 3+ 1.2 times the content.

14. The preparation method according to claim 12 or 13, characterized in that: The oxidant is hydrogen peroxide, and / or the ion exchange resin is a sulfonic acid phosphate chelate ion exchange resin.

15. The preparation method according to claim 12, characterized in that The removal of ferrous sulfate is carried out at a temperature of 35° C. to 45° C. and a redox potential of 550 mV to 650 mV.

16. The preparation method according to claim 12, characterized in that Before solid-liquid separation, the ion exchange resin is washed with water.

17. The preparation method according to claim 1, characterized in that The mixed gas containing carbon monoxide is recovered and reused.

18. The preparation method according to claim 17, characterized in that: When the volume ratio of carbon monoxide to carbon dioxide in the carbon monoxide-containing mixed gas is (1:0.05)-(1:1), the carbon monoxide-containing mixed gas is ignited in air to be used as fuel.

19. Use of nickel sulfate prepared by the preparation method according to any one of claims 1 to 18 in preparing a precursor for a lithium nickel cobalt manganese oxide battery.

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