CN113403477B

CN113403477B - Comprehensive utilization method of nickel sulfide concentrate

Info

Publication number: CN113403477B
Application number: CN202110680994.6A
Authority: CN
Inventors: 谢小平; 谈伟军; 蔡楠; 湛金; 李鹏; 魏国; 党电邦; 孙峙; 李青春; 曹宏斌
Original assignee: Beijing Zhongke Yunteng Technology Co ltd; Qinghai Yellow River Mining Co ltd; Institute of Process Engineering of CAS; Huanghe Hydropower Development Co Ltd
Current assignee: Beijing Zhongke Yunteng Technology Co ltd; Qinghai Yellow River Mining Co ltd; Institute of Process Engineering of CAS; Huanghe Hydropower Development Co Ltd
Priority date: 2021-06-18
Filing date: 2021-06-18
Publication date: 2023-02-28
Anticipated expiration: 2041-06-18
Also published as: CN113403477A

Abstract

The invention provides a comprehensive utilization method of nickel sulfide concentrate, which comprises the following steps: selectively leaching metal elements in the nickel sulfide concentrate by a high-pressure oxygen leaching process to obtain a nickel sulfide concentrate leaching solution, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements; adding iron powder into the nickel sulfide concentrate leachate, and oxidizing by adopting a microbubble oxidation method to generate goethite type precipitates, so as to remove iron ions and copper ions in the leachate; adding sodium fluoride as a precipitator to perform precipitation reaction so as to remove calcium ions and magnesium ions in the leachate; cobalt ions and nickel ions are respectively separated by extraction process extraction to prepare and obtain a cobalt sulfate product and a nickel sulfate product. The method not only realizes the high-efficiency recycling of the nickel element in the nickel sulfide concentrate, but also further utilizes other metal elements to reduce the pollution to the environment, and is beneficial to improving the resource utilization rate and the utilization value of raw materials.

Description

Comprehensive utilization method of nickel sulfide concentrate

Technical Field

The invention belongs to the technical field of nickel sulfide concentrate utilization, and particularly relates to a comprehensive utilization method of nickel sulfide concentrate.

Background

Nickel is an important strategic metal resource, and is widely used in aerospace, military and civil industrial fields due to its good ductility, mechanical properties and chemical stability. In recent years, with the rapid development of the high-nickel ternary lithium battery industry, the market demand of nickel is rapidly increased. Among nickel mineral resources, polymetallic nickel sulfide concentrate is one of the most important nickel ore resources, and has a very important position in nickel resources in China and even in the world. At present, the nickel sulfide concentrate resource in the nickel ore resource which is globally explored accounts for about 40 percent. In recent years, an ultra-large magma copper-nickel sulfide ore deposit is found in the Ha-wood area in summer of Qinghai province in China, 106 million tons (average grade of 0.7%) of nickel metal of 332+333 level is proved, 21.77 million tons (average grade of 0.166%) of copper resource of 333 level is associated, and 3.81 million tons (average grade of 0.025%) of cobalt resource is changed into the second large nickel deposit in China. The discovery of the ultra-large nickel ore effectively relieves the current situation of the shortage of nickel resource markets in China. With the gradual development and utilization stage of the Hazaki copper-nickel sulfide ore, the development of a green and efficient nickel sulfide concentrate extraction technology has very important significance.

The common treatment methods for nickel ores comprise a pyrometallurgical process and a hydrometallurgical process, and the utilization of nickel sulfide concentrate leachate obtained by leaching nickel sulfide concentrate by a wet method in the prior art still has a plurality of problems: (1) The leaching solution of the nickel sulfide concentrate contains various metal elements such as Fe, ni, cu, co and the like, and the problem that how to remove impurities from metal impurities in the leaching solution so as to prepare nickel sulfate and utilize nickel elements still needs to be solved; (2) Iron elements rich in nickel sulfide concentrate cause high concentration of iron ions in leachate in a wet leaching process, and the recovery process flow and energy consumption of nickel are seriously influenced; (3) How to further utilize other metal elements to reduce the pollution to the environment in the process of preparing the nickel sulfate by utilizing the leaching solution is still a problem which needs to be solved urgently. Therefore, a comprehensive utilization method of nickel sulfide concentrate needs to be further explored, which not only can remove impurities from metal impurities in the leachate so as to prepare nickel sulfate to utilize nickel elements, but also can further utilize other metal elements in the process of preparing nickel sulfate so as to reduce pollution to the environment.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a comprehensive utilization method of nickel sulfide concentrate, which can not only solve the problem that metal impurities in a leaching solution of nickel sulfide concentrate influence the preparation of nickel sulfate so as to utilize nickel elements, but also further utilize other metal elements in the process of preparing nickel sulfate so as to reduce the pollution of nickel sulfide concentrate to the environment.

In order to realize the purpose, the invention provides a comprehensive utilization method of nickel sulfide concentrate, which comprises the following steps:

s10, placing the nickel sulfide concentrate into a high-pressure kettle, adding leaching solution, and introducing oxygen with preset pressure into the leaching solution to leach metal elements in the nickel sulfide concentrate, so as to obtain nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements; wherein the predetermined pressure is 2.0 Mpa-3.0 Mpa, and the leaching temperature is 150-180 ℃;

s20, adding reduced iron powder into the nickel sulfide concentrate leachate to reduce and replace copper ions in the leachate, reducing the iron ions in the leachate into ferrous ions, and performing solid-liquid separation after the reaction is finished to obtain a first liquid phase solution and obtain a solid-phase sponge copper product;

s30, oxidizing the first solution by adopting a micro-bubble oxidation method to generate goethite type precipitates, and performing solid-liquid separation after the reaction is finished to obtain a liquid-phase second solution and obtain a solid-phase goethite product;

s40, adding sodium fluoride serving as a precipitating agent into the second solution to enable magnesium ions and calcium ions in the second solution to have a precipitation reaction, and after the reaction is finished, carrying out solid-liquid separation to obtain a liquid-phase third solution;

s50, preparing an extraction organic phase containing a P507 extraction agent, taking the third solution as an extraction water phase, extracting and separating cobalt ions through an extraction process, and separating after extraction is finished to obtain a loaded organic phase and a nickel-containing raffinate;

s60, carrying out back extraction on the loaded organic phase to obtain cobalt-containing back extraction liquid, and preparing a cobalt sulfate product by taking the cobalt-containing back extraction liquid as a raw material;

s70, preparing and obtaining a nickel sulfate product by taking the nickel-containing raffinate as a raw material.

Preferably, in the step S10, the leaching solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 40g/L to 80g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 100g/L to 300g/L, and the leaching time is 200min to 400min.

Further preferably, in the step S10, the concentration of the sulfuric acid solution is 40g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the predetermined pressure is 2.5Mpa, the leaching temperature is 160 ℃, and the leaching time is 300min.

Preferably, in the step S20, the addition amount of the reduced iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3g/L to 5g/L.

Preferably, the step S30 specifically includes: heating the first solution to a preset temperature, introducing oxygen into the first solution, oxidizing ferrous ions in the first solution into iron ions, and hydrolyzing the iron ions to generate goethite-type precipitates.

Further preferably, the predetermined temperature is 70-100 ℃, the gas flow rate of introducing oxygen into the first solution is 0.8-1.2L/min, and the reaction time is 300-500 min; the pH value in the reaction process is controlled to be 3-4.

Preferably, the step S40 specifically includes: and (2) placing the second solution in a constant-temperature water bath, stirring, adding a sodium carbonate solution to enable the second solution to reach a preset pH value, adding sodium fluoride serving as a precipitating agent into the second solution, carrying out precipitation reaction on magnesium ions and calcium ions in the second solution and the sodium fluoride, and carrying out solid-liquid separation after the reaction is finished to obtain a liquid-phase third solution.

Further preferably, the temperature of the constant-temperature water bath kettle is 70-100 ℃, and the preset pH value is 4-5; the excess coefficient of the amount of the sodium fluoride is 1.25 to 2.0 based on the amount of the magnesium ions and the calcium ions in the second solution to be completely precipitated.

Preferably, in the step S50,

firstly, preparing an extraction organic phase containing a P204 extraction agent, taking the third solution as an extraction water phase, removing impurities through an extraction process, and separating after extraction to obtain a third solution after impurity removal;

then, the extraction organic phase containing the P507 extraction agent is used for carrying out extraction separation on cobalt ions on the third solution after impurity removal.

Preferably, the step S60 specifically includes:

washing the loaded organic phase by using a sulfuric acid solution with the concentration of 0.1-0.4 mol/L;

carrying out back extraction on the washed loaded organic phase by using a sulfuric acid solution with the concentration of 1.0-2.0 mol/L to obtain a cobalt sulfate solution;

and heating, evaporating and concentrating the cobalt sulfate solution, and then cooling and crystallizing to obtain the cobalt sulfate product.

Preferably, the step S70 specifically includes:

adding sodium hydroxide solution into the nickel-containing raffinate, controlling the temperature of the reaction solution to be 80-100 ℃, controlling the pH value of the reaction solution to be 9-10, and after the reaction is finished, carrying out solid-liquid separation to obtain solid-phase nickel hydroxide precipitate;

dissolving the nickel hydroxide precipitate by using a sulfuric acid solution to obtain a nickel sulfate solution; controlling the reaction temperature to be 50-80 ℃, controlling the pH value of the reaction solution to be 3-4, and obtaining the nickel concentration in the nickel sulfate solution to be 80-100 g/L;

and (3) heating, evaporating and concentrating the nickel sulfate solution at 90-100 ℃ until the concentration of nickel is more than 300g/L, and then cooling, cooling and crystallizing to obtain a nickel sulfate product.

Has the advantages that: according to the invention, high-pressure oxygen is introduced, the high-pressure oxygen leaching process is utilized to realize the high-efficiency leaching of valuable metals nickel, cobalt and copper in the nickel sulfide concentrate, the leaching of iron is well inhibited, then, the goethite method is adopted to efficiently remove iron ion impurities in the nickel sulfide concentrate leachate, and the influence of high-concentration iron ions on the recovery process flow and energy consumption of nickel is solved; and finally, removing impurities of metal impurities in the nickel sulfide concentrate leaching solution in sequence, and preparing a nickel sulfate product to recycle nickel elements. The separated iron element and copper element can be directly sold in the form of iron slag and sponge copper, and the cobalt element is recycled by preparing a cobalt sulfate product, so that the method not only realizes the high-efficiency recycling of the nickel element in the nickel sulfide concentrate, but also further recycles other metal elements, is favorable for improving the utilization value and the resource utilization rate of raw materials, and reduces the pollution of the raw materials to the environment.

Drawings

Fig. 1 is a flow chart of a method for comprehensive utilization of nickel sulfide concentrate according to an embodiment of the present invention;

FIG. 2 is a graph showing the effect of leaching temperature on nickel sulfide concentrate leaching in example 1 of the present invention;

FIG. 3 is a graph showing the effect of oxygen pressure on nickel sulfide concentrate leaching in example 1 of the present invention;

fig. 4 is a graph showing the relationship between the amount of iron powder added and the concentration of copper ions in the process of reduction and replacement of copper ions by reduced iron powder in the leachate of nickel sulfide concentrate according to example 2 of the present invention;

fig. 5 is a graph showing a relationship between pH and an ion removal rate of each metal ion in the leachate in a reaction process of generating a goethite-type precipitate by using a microbubble oxidation method in example 2 of the present invention;

FIG. 6 is an X-ray diffraction (XRD) pattern of the iron slag in example 2 of the present invention;

FIG. 7 is a graph showing the relationship between the terminal pH and the removal rates of calcium ions and magnesium ions from the leachate of nickel sulfide concentrate according to example 3 of the present invention;

FIG. 8 is a graph showing the relationship between the reaction temperature and the removal rate of calcium ions and magnesium ions from the leachate of nickel sulfide concentrate in example 3 according to the present invention;

fig. 9 is a graph showing the relationship between the excess factor of the amount of sodium fluoride used and the removal rate of calcium ions and magnesium ions from the leachate of nickel sulfide concentrate in example 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in detail below with reference to the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the invention shown in the drawings and described in accordance with the drawings are exemplary only, and the invention is not limited to these embodiments.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the scheme according to the present invention are shown in the drawings, and other details not so relevant to the present invention are omitted.

The embodiment of the invention provides a comprehensive utilization method of nickel sulfide concentrate, and with reference to figure 1, the method comprises the following steps:

and S10, placing the nickel sulfide concentrate into a high-pressure kettle, adding leaching solution, and introducing oxygen with preset pressure into the leaching solution to leach metal elements in the nickel sulfide concentrate, so as to obtain a nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements.

Preferably, the predetermined pressure is 2.0MPa to 3.0MPa, and the leaching temperature is 150 ℃ to 180 ℃.

Further preferably, the predetermined pressure is 2.5Mpa and the leaching temperature is 160 ℃.

Preferably, the leaching solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 40 g/L-80 g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 100 g/L-300 g/L, and the leaching time is 200 min-400 min.

Further preferably, the concentration of the sulfuric acid solution is 40g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the predetermined pressure is 2.5Mpa, and the leaching time is 300min.

By adopting the high-pressure oxygen leaching process, the leaching of iron can be well inhibited, and the selective high-efficiency leaching of nickel sulfide concentrate is realized.

And S20, adding reduced iron powder into the nickel sulfide concentrate leachate to reduce and replace copper ions in the leachate, reducing iron ions in the leachate into ferrous ions, and performing solid-liquid separation after the reaction is finished to obtain a first liquid phase solution and obtain a solid-phase sponge copper product.

Preferably, the addition amount of the reduced iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3g/L to 5g/L.

Further preferably, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the nickel sulfide concentrate leachate is 3.88g/L.

The reduced iron powder reduces copper ions in the leachate, so that the copper ions are replaced in a form of sponge copper, and then the sponge copper precipitate is filtered to achieve the purpose of removing the copper ions in the leachate; in addition, the reduced iron powder also plays a role in reducing iron ions in the leachate into ferrous ions.

And S30, oxidizing the first solution by adopting a micro-bubble oxidation method to generate goethite type precipitates, and performing solid-liquid separation after the reaction is finished to obtain a liquid-phase second solution and obtain a solid-phase goethite product.

Goethite is one of the main minerals containing hydrous oxides, generally called alpha-form monohydrated iron oxide, and its composition is alpha-Fe ₂ O ₃ ·H ₂ The iron content of the precipitate of O or alpha-FeOOH is high, and the adsorption to other metal ions in the solution is less, so that the recovery rate of metallic iron can be higher by adopting the goethite method.

The specific reaction process of removing iron by the goethite method comprises an oxidation reaction and a hydrolysis reaction:

and (3) oxidation reaction:

4Fe ²⁺ +O ₂ +4H ⁺ →4Fe ³⁺ +2H ₂ O

and (3) hydrolysis reaction:

Fe ³⁺ +H ₂ O→FeOH ²⁺ +H ⁺

FeOH ²⁺ +H ₂ O→FeOOH+2H ⁺

oxygen first Fe ²⁺ Oxidation to Fe ³⁺ ，Fe ³⁺ Forming simple hydrolysate FeOH through hydrolysis ²⁺ The hydrolysate is further hydrolyzed to generate FeOOH microcrystals, and the FeOOH microcrystals are aggregated and grown to form goethite type solid precipitate alpha-FeOOH, wherein Fe ²⁺ Oxidation and Fe ³⁺ The hydrolysis reactions occur sequentially in a compositional series.

Preferably, the predetermined temperature is 70-100 ℃, the gas flow rate of introducing oxygen into the first solution is 0.8-1.2L/min, and the reaction time is 300-500 min; the pH value in the reaction process is controlled to be 3-4.

Further preferably, the predetermined temperature is 80 ℃, the gas flow rate of introducing oxygen into the first solution is 1L/min, and the reaction time is 480min.

The oxidation reaction is carried out by oxygen, the oxidation process relates to physical processes such as gas-liquid diffusion, mass transfer and the like, the speed is low, and Fe ³⁺ Extremely unstable in solution, and therefore Fe ³⁺ FeOH is generated by hydrolysis reaction ²⁺ Is very fast. But if Fe is in solution ³⁺ Content is too high (>1 g/L), fe is easily caused ³⁺ Formation of Fe (OH) ₃ Colloidal precipitation, and therefore, in the process of removing iron by the goethite process, the key is to control Fe ²⁺ The invention adopts a microbubble oxidation method to oxidize Fe ²⁺ Controlling the flow of the oxygen to control Fe ²⁺ The oxidation process of (2) to solve the problem of difficult iron removal control by goethite method.

In the process of removing iron by goethite method, fe ²⁺ Oxidation rate of ion and [ H ] ⁺ ] ^0.25 Inversely proportional, fe in solution with increasing pH ²⁺ Has an increased oxidation rate of Fe ³⁺ The quantity of the ion hydrolysis precipitate is increased, and the iron removal efficiency is obviously improved; however, if the pH is too high, fe is formed by oxidation ³⁺ The ion concentration is more than 1g/L, which is easy to cause Fe ³⁺ Quickly precipitate and generate Fe (OH) ₃ Colloid, so that a large amount of nickel and cobalt are adsorbed, and the loss rate of the nickel and the cobalt is increased sharply.

And S40, adding sodium fluoride serving as a precipitator into the second solution to enable magnesium ions and calcium ions in the second solution to have precipitation reaction, and performing solid-liquid separation after the reaction is finished to obtain a liquid-phase third solution.

Preferably, the step S40 specifically includes: and (3) placing the second solution in a constant-temperature water bath, stirring, adding a sodium carbonate solution to enable the second solution to reach a preset pH value, adding sodium fluoride serving as a precipitating agent into the second solution, carrying out precipitation reaction on magnesium ions and calcium ions in the second solution and the sodium fluoride, and carrying out solid-liquid separation after the reaction is finished to obtain a liquid-phase third solution.

The principle of removing calcium and magnesium from the leachate by using sodium fluoride is as follows:

Ca ²⁺ +2F ^- →CaF ₂ ↓，K _sp ＝2.7×10 ^-11

Mg ²⁺ +2F ^- →MgF ₂ ↓，K _sp ＝6.5×10 ^-9

preferably, the temperature of the constant-temperature water bath is 70-100 ℃, and the preset pH value is 4-5; the excess coefficient of the amount of the sodium fluoride is 1.25 to 2.0 based on the amount of the magnesium ions and the calcium ions in the second solution to be completely precipitated.

Further preferably, the temperature of the constant-temperature water bath is 90 ℃, and the preset pH value is 4.5; the excess factor of the amount of sodium fluoride was 1.5 based on the amount of magnesium ions and calcium ions in the second solution completely precipitated.

In order to achieve the best calcium and magnesium removal efficiency, excessive sodium fluoride needs to be added, but if the excessive coefficient of the amount of the sodium fluoride is too large, the amount of the sodium fluoride is increased continuously, the calcium and magnesium removal efficiency is not increased obviously, and F in the solution is caused ^- Excessive ions produce new impurities.

Calcium fluoride and magnesium fluoride are generated in the process of precipitating calcium and magnesium by sodium fluoride, and effective collision among molecules is increased along with the increase of temperature, so that precipitates are easily formed; and, high temperature favors Ca ²⁺ 、Mg ²⁺ The enrichment of the ions enables the ions to be more effectively gathered together to form a large-particle precipitate, and the formed large-particle precipitate can cause Ca ²⁺ 、Mg ²⁺ Ions are adsorbed on the surface of the filter material to promote precipitation of precipitates, so that calcium fluoride and magnesium fluoride are easy to form colloid if the temperature is too high, and the problems of long filtering process time, difficult filtering, metal ion adsorption and the like are caused.

And S50, preparing an extraction organic phase containing a P507 extraction agent, taking the third solution as an extraction water phase, extracting and separating cobalt ions through an extraction process, and separating after extraction is finished to obtain a loaded organic phase and a nickel-containing raffinate.

Preferably, the step S50 specifically includes:

and S501, preparing an extraction organic phase containing a P204 extracting agent, taking the third solution as an extraction water phase, removing impurities through an extraction process, and separating after extraction to obtain a third solution after impurity removal.

Preferably, the volume fraction of the P204 extractant in the extracted organic phase is 20-30%, the saponification rate of the P204 extractant is 50-60%, the extraction phase ratio is 1-2.

Further preferably, the volume fraction of the P204 extractant in the extracted organic phase is 20%, the saponification rate of the P204 extractant is 60%, the extraction phase ratio is 1.

Preferably, the P204 extractant is used for removing trace amounts of copper, iron, and aluminum metal impurities in the third solution.

Step S502, carrying out extraction separation of cobalt ions on the third solution after impurity removal by using the extraction organic phase containing the P507 extraction agent:

preparing an extraction organic phase containing a P507 extracting agent, taking the third solution after impurity removal as an extraction water phase, extracting and separating cobalt ions through an extraction process, and separating after extraction is finished to obtain a loaded organic phase and a nickel-containing raffinate.

Preferably, the volume fraction of the P507 extracting agent in the extracted organic phase is 20-30%, the saponification rate of the P507 extracting agent is 70-80%, the extraction temperature is 20-30 ℃, the extraction time is 10-20 min, the standing time is 10-20 min, and the pH value in the reaction process is controlled to be 3-4, wherein the extraction ratio is 1.5.

Further preferably, the volume fraction of the P507 extractant in the extracted organic phase is 25%, the saponification rate of the P507 extractant is 70%, the extraction phase ratio is 2.

And S60, carrying out back extraction on the loaded organic phase to obtain cobalt-containing back extraction liquid, and preparing a cobalt sulfate product by taking the cobalt-containing back extraction liquid as a raw material.

Preferably, the step S60 specifically includes:

step S601, washing the loaded organic phase by using a sulfuric acid solution with the concentration of 0.1-0.4 mol/L.

And step S602, carrying out back extraction on the washed loaded organic phase by using a sulfuric acid solution with the concentration of 1.0-2.0 mol/L to obtain a cobalt sulfate solution.

Preferably, the concentration of the sulfuric acid solution is 2mol/L, the stripping time is 20min, and the extraction phase ratio (O/A) is 2.5:1.

and S603, heating, evaporating and concentrating the cobalt sulfate solution, and then cooling, cooling and crystallizing to obtain the cobalt sulfate product.

Preferably, the heating temperature is 90-100 ℃, the temperature for cooling is 50-60 ℃, and the crystallization time is 2-3 h.

Further preferably, the heating temperature is 90 ℃, the cooling temperature is 58 ℃, and the crystallization time is 2h.

And S70, preparing and obtaining a nickel sulfate product by taking the nickel-containing raffinate as a raw material.

Preferably, the S70 specifically includes:

and step S701, adding a sodium hydroxide solution into the nickel-containing raffinate, and performing solid-liquid separation after the reaction is finished to obtain solid-phase nickel hydroxide precipitate.

Preferably, the temperature of the reaction solution is controlled to be 80-100 ℃, the pH value of the reaction solution is controlled to be 9-10, the mass fraction of the sodium hydroxide solution is 5-15%, and the reaction time is 3-5 h.

Further preferably, the temperature of the reaction solution is controlled to be 90 ℃, the pH value of the reaction solution is controlled to be 9, the mass fraction of the sodium hydroxide solution is 10%, and the reaction time is 4 hours.

And S702, dissolving the nickel hydroxide precipitate by using a sulfuric acid solution to obtain a nickel sulfate solution.

Preferably, the reaction temperature is controlled to be 50-80 ℃, the pH value of the reaction solution is controlled to be 3-4, the reaction time is 3-5 h, and the concentration of nickel in the obtained nickel sulfate solution is 80-100 g/L.

Further preferably, the reaction temperature is controlled to be 60 ℃, the pH value of the reaction solution is controlled to be 3.5-3.6, the reaction time is 4 hours, and the concentration of the nickel in the nickel sulfate solution is 100g/L.

And S703, heating, evaporating and concentrating the nickel sulfate solution, and then cooling and crystallizing to prepare a nickel sulfate product.

Preferably, the heating temperature is controlled to be 90-100 ℃, the nickel sulfate solution is concentrated until the concentration of nickel is more than 300g/L, the temperature is controlled to be reduced to 50-60 ℃, and the pH value in the reaction process is controlled to be 3-4.

Further preferably, the heating temperature is controlled to be 90 ℃, the temperature for cooling is controlled to be 53 ℃, and the pH value in the reaction process is controlled to be 3.5-3.6.

The nickel element in the nickel sulfide concentrate can be recycled by preparing the nickel sulfate product.

The method for recycling a nickel sulfide concentrate as described above will be described with reference to specific examples, and it will be understood by those skilled in the art that the following examples are specific examples of the method for recycling a nickel sulfide concentrate as described above in the present invention, and are not intended to limit the entirety thereof.

The nickel sulfide concentrate according to the embodiment of the present invention is provided by Qinghai yellow river mining Limited liability company, and the main components and the phase analysis of the nickel sulfide concentrate are shown in tables 1 and 2.

Table 1: main metal component of nickel sulfide concentrate

Table 2: full element semi-quantitative analysis (XRF) of nickel sulfide concentrate

Example 1: preparation of nickel sulfide concentrate leachate

Putting the nickel sulfide concentrate into an autoclave, adding a sulfuric acid solution, and introducing oxygen with preset pressure into the sulfuric acid solution to leach metal elements in the nickel sulfide concentrate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements, so as to obtain a nickel sulfide concentrate leachate.

(1) Investigating the influence of the leaching temperature on the preparation of the nickel sulfide concentrate leaching solution

Wherein the reaction conditions are selected as follows: the concentration of the sulfuric acid solution is 40g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the pressure of introduced oxygen is 2.5Mpa, and the leaching time is 300min; under the above conditions, the influence of different leaching temperatures on the leaching of the metal elements in the nickel sulfide concentrate was examined separately.

Fig. 2 is a graph showing the effect of leaching temperature on the leaching of nickel sulphide concentrate, and the experimental results obtained under the above conditions are shown in fig. 2.

As can be seen from fig. 2, under the condition of keeping other experimental conditions unchanged, the leaching efficiency of iron is continuously reduced, and the leaching efficiency of nickel, cobalt and copper is continuously increased along with the increase of the leaching temperature. When the temperature is 110 ℃, the leaching efficiency of iron is 40.34%, and the leaching efficiencies of nickel, cobalt and copper are 59.5%, 51.5% and 50.9% respectively; when the temperature is 160 ℃, the leaching efficiency of iron is only 32.3%, and the leaching efficiencies of nickel, cobalt and copper are 77.4%, 65.7% and 67.4% respectively; therefore, the leaching effects of nickel, cobalt, copper and iron are comprehensively considered, and the optimal leaching temperature of 160 ℃ is selected, so that the leaching of iron is inhibited while the high-efficiency leaching of nickel, cobalt and copper in the nickel sulfide concentrate is ensured.

(2) Investigating the influence of oxygen pressure on the preparation of nickel sulfide concentrate leachate

Wherein the reaction conditions are selected as follows: the concentration of the sulfuric acid solution is 40g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the leaching temperature is 160 ℃, and the leaching time is 300min; under the above conditions, the influence of different oxygen pressures on the leaching of the metal elements in the nickel sulfide concentrate was examined separately.

Fig. 3 is a graph showing the effect of oxygen pressure on the leaching of nickel sulphide concentrate, and the experimental results obtained under the above conditions are shown in fig. 3.

As can be seen from fig. 3, under the condition that other experimental conditions are kept unchanged, along with the increase of the pressure of the introduced oxygen, the leaching efficiency of nickel, cobalt and copper in the nickel sulfide concentrate is continuously increased, and the leaching efficiency of iron is continuously reduced, when the pressure of the oxygen is 2.5Mpa, the leaching rates of nickel, cobalt and copper are respectively 96.5%, 97.8% and 81.9%, and the leaching rate of iron is only 16.77%, so that the leaching of nickel, cobalt and copper can be improved while the leaching of iron is inhibited by increasing the pressure of the oxygen, and the selective leaching of metal elements is realized; in view of the above, the oxygen pressure of 2.5MPa is preferably selected.

In conclusion, the optimized process conditions for preparing the nickel sulfide concentrate leaching solution are as follows: the concentration of the sulfuric acid solution is 40g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the oxygen pressure is 2.5Mpa, the leaching temperature is 160 ℃, and the leaching time is 300min.

Under the optimized process conditions, after the leaching reaction of the nickel sulfide concentrate is finished, filtering the nickel sulfide concentrate to obtain a nickel sulfide concentrate leachate, wherein the leaching rates of nickel, cobalt, copper and iron in the nickel sulfide concentrate are 96.5%, 97.8%, 81.9% and 16.77% respectively, and the metal elements in the nickel sulfide concentrate leachate at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements.

Example 2: removing copper ions and iron ions in nickel sulfide concentrate leaching solution

Step one, adding reduced iron powder to the nickel sulfide concentrate leachate obtained under the optimized process conditions of example 1 to reduce copper ions in the leachate, so that the copper ions are replaced in the form of sponge copper, reducing the iron ions in the leachate to ferrous ions, and performing solid-liquid separation after the reduction reaction is completed to obtain a solid-phase sponge copper product and a liquid-phase first solution, namely the leachate from which the copper ions are removed.

Step two, oxidizing the first solution by adopting a micro-bubble oxidation method to generate goethite type precipitates, and performing solid-liquid separation after the reaction is finished to obtain a solid-phase goethite product and a liquid-phase second solution: heating the first solution to 80 ℃, introducing oxygen into the first solution to oxidize ferrous ions in the first solution into iron ions, hydrolyzing the iron ions to generate goethite type precipitates, filtering after the reaction is finished to obtain a solid-phase goethite product, namely iron slag, and obtaining a liquid-phase second solution, namely the leachate without copper ions and iron ions; wherein the gas flow of oxygen is 1L/min, and the reaction time is 480min.

(1) Under the above conditions, the influence of the addition amount of the reduced iron powder on the removal of copper ions and iron ions in the nickel sulfide concentrate leachate was examined.

Fig. 4 is a graph showing the relationship between the amount of iron powder added and the concentration of copper ions in the process of reducing and replacing copper ions by reduced iron powder in the leachate of nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 4.

As can be seen from fig. 4, when the amount of iron powder added is such that the concentration of reduced iron powder in the leachate of nickel sulfide concentrate reaches 3.0g/L or more, the concentration of copper ions in the solution is greatly reduced, so the amount of iron powder added in the solution of the present invention is such that the concentration of reduced iron powder in the leachate of nickel sulfide concentrate is preferably 3.0g/L to 5.0g/L; when the addition amount of the iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3.88g/L, the concentration of copper ions in the solution is reduced from 2940mg/L to 3ppm, at this time, the copper ions in the leachate can be removed completely theoretically, the addition amount of the iron powder is increased continuously, and the concentration of the copper ions is basically unchanged, so the addition amount of the reduced iron powder is selected to be the optimum concentration of the reduced iron powder in the nickel sulfide concentrate leachate of 3.88g/L.

(2) Under the conditions, the influence of pH in the reaction process of generating goethite type precipitates by using a microbubble oxidation method on the removal of copper ions and iron ions in the nickel sulfide concentrate leachate is examined, wherein the adding amount of the reduced iron powder is selected so that the concentration of the reduced iron powder in the nickel sulfide concentrate leachate is 3.88g/L.

Fig. 5 is a graph showing the relationship between the pH and the ion removal rate of each metal ion in the leachate during the reaction process of producing the goethite-type precipitate by the microbubble oxidation method, and the experimental results obtained under the above conditions are shown in fig. 5.

As can be seen from fig. 5, as the pH of the reaction increases from 1.5 to 3, the removal efficiency of iron ions in the nickel sulfide concentrate leachate increases from 36.5% to 92%, and the concentration of nickel ions and cobalt ions in the leachate is basically unchanged, and the ion removal rate is close to 0 and remains unchanged. When the reaction pH is further increased to 5, the removal efficiency of iron ions remains substantially unchanged, but the ion removal rate of nickel ions and cobalt ions sharply increases at this time, and the ion loss rate thereof sharply increases. This is due to Fe ²⁺ Oxidation rate of [ H ] ⁺ ] ^0.25 Inversely proportional, fe in solution with increasing pH ²⁺ Accelerated oxidation of ions, fe ³⁺ The number of the hydrolyzed precipitates of the ions is increased, and the iron removal efficiency is obviously improved; however, when the pH is 5, fe is produced by oxidation due to the excessive pH at that time ³⁺ Ion concentration greater than 1g/L, resulting in Fe ³⁺ Rapidly precipitate and form Fe (OH) ₃ Colloid, so that a large amount of nickel ions and cobalt ions are adsorbed, resulting in a sharp increase in the loss rate of nickel ions and cobalt ions. Therefore, when the goethite method is adopted for removing iron, the pH value is controlled to be optimal between 3 and 4 in the reaction process of forming goethite type precipitates by the microbubble oxidation method.

In summary, the optimized process conditions for removing copper ions and iron ions in the leaching solution of the nickel sulfide concentrate are as follows: the addition amount of the reduced iron powder is such that the concentration of the reduced iron powder in the nickel sulfide concentrate leaching solution is 3.88g/L; the reaction process of forming goethite type precipitate by a microbubble oxidation method comprises the following steps: the flow of the introduced oxygen is 1L/min, the pH value of the reaction is 3.5, the reaction temperature is 80 ℃, and the reaction time is 480min.

Under the optimized process conditions, after the reaction is finished, carrying out solid-liquid separation to obtain iron slag precipitate and nickel sulfide concentrate leachate without copper ions and iron ions.

The obtained iron slag was subjected to XRF full-element semi-quantitative analysis, and the XRF full-element semi-quantitative analysis results of the iron slag are shown in table 3.

Table 3: full elemental semi-quantitative analysis (XRF) of iron slag

As can be seen from Table 3, the main elements in the iron slag were Fe (65.7%), O (31.3%) and S (1.90%), and the other elements were Ni, co, si, al, cl, ca, etc.

Further, an ICP-OES inductively coupled plasma emission spectrometer was used to perform quantitative analysis on the iron slag, and the results of quantitative analysis of the main metal elements in the iron slag and analysis of the leachate components are shown in table 4.

Table 4: quantitative analysis (ICP-OES) of main metal elements in iron slag and analysis of leachate components

As can be seen from table 4, the Fe content in the iron slag can reach 55.9%, the iron slag can be sold as iron ore directly, and the Ni and Co contents are only 0.23% and 0.03%, indicating that the loss of nickel is below 3% and the cobalt is almost not lost; the concentration of iron ions in the nickel sulfide concentrate leachate obtained after iron removal by adopting the goethite method is only 0.012g/L.

FIG. 6 is an X-ray diffraction (XRD) pattern of the iron slag, and it can be seen from FIG. 6 that the iron slag obtained by the above process is a single-phase α -FeOOH.

Example 3: removing calcium ions and magnesium ions in nickel sulfide concentrate leaching solution

Placing the second solution obtained under the optimized process conditions of the example 2, namely the leachate without iron ions and copper ions in a constant-temperature water bath kettle and stirring, adding a sodium carbonate solution to enable the second solution to reach a preset pH value, adding sodium fluoride serving as a precipitator into the second solution, carrying out precipitation reaction on magnesium ions and calcium ions in the second solution and the sodium fluoride, and carrying out solid-liquid separation after the reaction is finished to obtain a liquid-phase third solution, namely the leachate without calcium ions and magnesium ions.

(1) And (4) investigating the influence of the end-point pH value on the removal of calcium ions and magnesium ions in the nickel sulfide concentrate leachate.

Wherein the reaction conditions are selected as follows: the temperature of the constant-temperature water bath is 90 ℃, the mass fraction of the sodium carbonate solution is 7%, the reaction time is 1.5h, and the excess coefficient of the amount of the sodium fluoride is 1.5 on the basis of the amount of the magnesium ions and the calcium ions in the second solution which are completely precipitated; the removal rates of magnesium ions and calcium ions in the leachate were examined respectively at predetermined pH values, i.e., end point pH values of 4.0, 4.5, and 5.0. Fig. 7 is a graph of the relationship between the end point pH and the removal rate of calcium and magnesium ions from the nickel sulphide concentrate leachate, and the experimental results obtained under the above conditions are shown in fig. 7.

As can be seen from fig. 7, as the end point pH increased from 4.0 to 4.5, the removal efficiency of magnesium increased from 95.16% to 98.61%, and the removal efficiency of calcium increased from 75.61% to 97.3%, at which time the increase in the removal efficiency of magnesium was insignificant and the removal efficiency of calcium increased significantly; when the end point pH is increased from 4.5 to 5.0, the removal efficiency of magnesium is changed from 98.61% to 98.86%, basically no change is made, and the removal efficiency of calcium is reduced from 97.3% to 96.48%. In summary, the final pH is preferably 4 to 5, and when the final pH is 4.5, the removal of calcium and magnesium ions from the nickel sulfide concentrate leachate is most effective.

(2) And investigating the influence of the reaction temperature on the removal of calcium ions and magnesium ions in the nickel sulfide concentrate leachate.

Wherein the reaction conditions are selected as follows: the mass fraction of the sodium carbonate solution is 7%, the end-point pH value is 4.5, and the reaction time is 1.5h; according to the reference of the dosage of completely precipitating the magnesium ions and the calcium ions in the second solution, the excess coefficient of the dosage of the sodium fluoride is 1.5, and the removal rates of the magnesium ions and the calcium ions in the leachate are respectively considered under the conditions that the temperature of a constant-temperature water bath, namely the reaction temperature, is 70 ℃, 80 ℃ and 90 ℃. Fig. 8 is a graph showing the relationship between the reaction temperature and the removal rate of calcium ions and magnesium ions from the leachate of nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 8.

As can be seen from fig. 8, as the reaction temperature was increased from 70 ℃ to 90 ℃, the removal efficiency of magnesium was changed from 99.52% to 98.61%, and the removal rate of magnesium was not substantially changed; the calcium removal efficiency is increased from 92.95% to 97.3%, and the calcium removal efficiency is slightly increased, which shows that the reaction temperature has no influence on the calcium and magnesium removal efficiency. However, under high temperature conditions, calcium fluoride and magnesium fluoride generated in the process of precipitation reaction of sodium fluoride with magnesium ions and calcium ions are easy to form colloid, which causes problems of long filtration process time, difficult filtration, metal ion adsorption and the like, so the reaction temperature should not be controlled too high. As described above, the reaction temperature is preferably from 70 ℃ to 100 ℃, and the reaction temperature is most preferably 90 ℃.

(3) And (3) investigating the influence of the excess coefficient of the using amount of the sodium fluoride on the removal of calcium ions and magnesium ions in the nickel sulfide concentrate leaching solution.

Wherein the reaction conditions are selected as follows: the temperature of the constant-temperature water bath kettle is 90 ℃, the mass fraction of the sodium carbonate solution is 7%, the reaction time is 1.5h, and the end-point pH value is 4.5; the removal rates of magnesium ions and calcium ions in the leachate were examined under the conditions of an excess coefficient of the amount of sodium fluoride of 1.0, 1.25, 1.5, 1.75 and 2.0, respectively. Fig. 9 is a graph showing the relationship between the excess factor of the amount of sodium fluoride used and the removal rate of calcium ions and magnesium ions from the leachate of nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 9.

As can be seen from fig. 9, when the excess factor of the amount of sodium fluoride was increased from 1.0 to 1.5, the removal efficiencies of calcium and magnesium were increased from 79.5% and 84.6% to 97.3% and 98.6%, respectively. The continuous increase of the dosage of the sodium fluoride has insignificant increase of the removal efficiency of the calcium and the magnesium and can cause F in the solution ^- Excessive ions produce new impurities. In summary, the excess factor of the amount of sodium fluoride is preferably 1.25 to 2.0, and the excess factor of the amount of sodium fluoride is preferably 1.5.

In summary, the optimized process conditions for removing copper ions and iron ions in the leaching solution of the nickel sulfide concentrate are as follows: the reaction temperature is 90 ℃, and the end-point pH value is 4.5; the excess factor of the amount of sodium fluoride was 1.5 based on the amount of magnesium ions and calcium ions in the second solution completely precipitated.

Example 4: extracting and separating cobalt ions in nickel sulfide concentrate leachate by an extraction process

Step one, preparing an extraction organic phase containing a P204 extraction agent, taking a third solution obtained under the optimized process conditions of example 3, i.e. a leachate from which magnesium ions and calcium ions are removed, as an extraction aqueous phase, removing impurities by an extraction process, and separating after extraction is completed to obtain a third solution from which impurities are removed, i.e. a leachate from which trace amounts of copper, iron and aluminum metal impurities are removed.

Wherein the reaction conditions are selected as follows: the volume fraction of the P204 extractant in the extracted organic phase is 20%, and the saponification rate of the P204 extractant is 60%; the extraction ratio is 1.

Step two, performing extraction separation of cobalt ions by using the extraction organic phase containing the P507 extraction agent relative to the third solution after impurity removal: preparing an extraction organic phase containing a P507 extraction agent, taking the third solution after impurity removal as an extraction water phase, extracting and separating cobalt ions through an extraction process, and separating after extraction to obtain a loaded organic phase and a nickel-containing raffinate, wherein the loaded organic phase is a cobalt-containing organic phase.

Wherein the reaction conditions are selected as follows: the volume fraction of the P507 extracting agent in the extracted organic phase is 25%, and the saponification rate of the P507 extracting agent in the extracted organic phase is 70%; the extraction ratio is 2.

Example 5: preparation of cobalt sulfate product

Step one, the loaded organic phase obtained in example 4 was washed with a sulfuric acid solution having a concentration of 0.2 mol/L.

And step two, carrying out back extraction on the washed loaded organic phase by using a sulfuric acid solution with the concentration of 2.0mol/L to obtain a cobalt sulfate solution.

Wherein the reaction conditions are selected as follows: the concentration of the sulfuric acid solution is 2mol/L, the back extraction time is 20min, and the extraction phase ratio (O/A) is 2.5:1.

and step three, heating, evaporating and concentrating the cobalt sulfate solution, and then cooling and crystallizing to obtain the cobalt sulfate product.

Wherein the reaction conditions are selected as follows: the heating temperature is 90 ℃, the cooling temperature is 58 ℃, and the crystallization time is 2h.

Example 6: preparation of nickel sulfate product

Step one, adding sodium hydroxide solution into the nickel-containing raffinate obtained in the example 4, and after the reaction is finished, performing solid-liquid separation to obtain solid-phase nickel hydroxide precipitate.

Wherein the temperature of the reaction solution is controlled to be 90 ℃, the pH value of the reaction solution is controlled to be 9, the mass fraction of the sodium hydroxide solution is 10%, and the reaction time is 4h.

And step two, dissolving the nickel hydroxide precipitate by using a sulfuric acid solution to obtain a nickel sulfate solution.

Wherein the reaction temperature is controlled to be 60 ℃, the pH value of the reaction solution is controlled to be 3.5-3.6, the reaction time is 4 hours, and the concentration of the nickel in the nickel sulfate solution is 100g/L.

And step three, heating, evaporating and concentrating the nickel sulfate solution at 90 ℃ until the concentration of nickel is more than 300g/L, then cooling, crystallizing, controlling the temperature to be 53 ℃, and controlling the pH value in the reaction process to be 3.5-3.6 to prepare the nickel sulfate product.

The nickel element in the nickel sulfide concentrate can be recycled by preparing the nickel sulfate product

According to the comprehensive utilization method of the nickel sulfide concentrate, high-pressure oxygen is introduced, the high-pressure oxygen leaching process is utilized to realize high-efficiency leaching of valuable metals nickel, cobalt and copper in the nickel sulfide concentrate, leaching of iron is well inhibited, leaching rates of nickel, cobalt, copper and iron in the nickel sulfide concentrate are respectively 96.5%, 97.8% and 81.9%, and the leaching rate of iron is only 16.7%; then, the goethite method is adopted to efficiently remove iron ion impurities in the nickel sulfide concentrate leaching solution, so that the influence of iron ions with higher concentration on the recovery process flow and energy consumption of nickel is avoided; and finally, removing impurities of metal impurities in the nickel sulfide concentrate leaching solution in sequence, and preparing a nickel sulfate product to recycle nickel elements. The separated iron element and copper element can be directly sold in the form of iron slag and sponge copper, and the cobalt element is recycled by preparing a cobalt sulfate product, so that the invention not only realizes the high-efficiency recycling of the nickel element in the nickel sulfide concentrate, but also further recycles other metal elements, is favorable for improving the utilization value and the resource utilization rate of raw materials, and reduces the pollution of the raw materials to the environment.

The foregoing is directed to embodiments of the present application and it is noted that numerous modifications and adaptations may be made by those skilled in the art without departing from the principles of the present application and are intended to be within the scope of the present application.

Claims

1. A method for comprehensively utilizing nickel sulfide concentrate is characterized by comprising the following steps:

s10, placing the nickel sulfide concentrate into a high-pressure kettle, adding leaching solution, and introducing oxygen with preset pressure into the leaching solution to leach metal elements in the nickel sulfide concentrate, so as to obtain a nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements; wherein the preset pressure is 2.0MPa to 3.0MPa, and the leaching temperature is 150 ℃ to 180 ℃;

s30, oxidizing the first solution by adopting a micro-bubble oxidation method to generate goethite type precipitates, and performing solid-liquid separation after the reaction is finished to obtain a liquid-phase second solution and obtain a solid-phase goethite product; the step S30 specifically includes: heating the first solution to 70-100 ℃, introducing oxygen into the first solution at a gas flow rate of 0.8-1.2L/min, oxidizing ferrous ions in the first solution into iron ions, hydrolyzing the iron ions to generate goethite type precipitates, wherein the reaction time is 300-500 min, and the pH value in the reaction process is controlled to be 3-4;

2. The comprehensive utilization method according to claim 1, wherein in the step S10, the leaching solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 40 g/L-80 g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 100 g/L-300 g/L, and the leaching time is 200 min-400 min.

3. The comprehensive utilization method according to claim 2, wherein in the step S10, the concentration of the sulfuric acid solution is 40g/L, the solid-to-liquid ratio of the nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the predetermined pressure is 2.5MPa, the leaching temperature is 160 ℃, and the leaching time is 300min.

4. The integrated utilization method according to claim 1, wherein, in the step S20, the fine reduced iron is added in an amount such that the concentration of the fine reduced iron in the nickel sulfide concentrate leachate is 3g/L to 5g/L.

5. The comprehensive utilization method according to claim 1, wherein the step S40 specifically includes: and (3) placing the second solution in a constant-temperature water bath, stirring, adding a sodium carbonate solution to enable the second solution to reach a preset pH value, adding sodium fluoride serving as a precipitating agent into the second solution, carrying out precipitation reaction on magnesium ions and calcium ions in the second solution and the sodium fluoride, and carrying out solid-liquid separation after the reaction is finished to obtain a liquid-phase third solution.

6. The comprehensive utilization method according to claim 5, wherein in the step S40, the temperature of the constant-temperature water bath is 70 ℃ to 100 ℃, and the predetermined pH value is 4 to 5; the excess coefficient of the amount of the sodium fluoride is 1.25 to 2.0 based on the amount of the magnesium ions and the calcium ions in the second solution to be completely precipitated.

7. The comprehensive utilization method according to claim 1, wherein in said step S50,

8. The comprehensive utilization method according to claim 1, wherein the step S60 specifically includes:

9. The comprehensive utilization method according to claim 1, wherein the step S70 specifically includes:

and (3) heating, evaporating and concentrating the nickel sulfate solution at the heating temperature of 90-100 ℃ until the concentration of nickel is more than 300g/L, and then cooling, cooling and crystallizing to obtain a nickel sulfate product.