阅读说明：本技术 一种硫化镍精矿的综合利用方法 (Comprehensive utilization method of nickel sulfide concentrate ) 是由 魏国 蔡楠 湛金 李鹏 谈伟军 党电邦 孙峙 李青春 郑晓洪 于 2021-06-18 设计创作，主要内容包括：本发明提供了一种硫化镍精矿的综合利用方法,所述方法包括：通过机械活化-微气泡浸出工艺以选择性浸出硫化镍精矿中的金属元素获得硫化镍精矿浸出液,所述金属元素至少包括铜、铁、钴、镍、镁和钙元素；向硫化镍精矿浸出液中加入铁粉,然后采用微气泡氧化法进行氧化,以生成针铁矿型沉淀物,从而去除所述浸出液中铁离子和铜离子；加入氟化钠作为沉淀剂发生沉淀反应从而去除所述浸出液中钙离子和镁离子；通过萃取工艺萃取分别分离出钴离子和镍离子以制备获得硫酸钴产品和硫酸镍产品。该方法不仅实现了硫化镍精矿中镍元素的高效回收利用,还进一步利用了其他金属元素以减少其对环境的污染,有利于提升了原材料的资源利用率和利用价值。(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 mechanical activation-microbubble 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.)

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

s10, placing the nickel sulfide concentrate into a ball mill for ball milling treatment, and performing mechanical activation treatment on the nickel sulfide concentrate to form activated nickel sulfide concentrate;

s20, placing the activated nickel sulfide concentrate into a leaching solution, introducing gas into the leaching solution to form micro bubbles, and stirring to leach metal elements in the activated nickel sulfide concentrate to obtain a nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements;

s30, 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;

s40, 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;

s50, 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;

s60, 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 to obtain a loaded organic phase and a nickel-containing raffinate after extraction is finished;

s70, 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;

s80, preparing and obtaining a nickel sulfate product by taking the nickel-containing raffinate as a raw material.

2. The comprehensive utilization method according to claim 1, wherein the process conditions of the ball milling treatment in the step S10 include: the ball milling strength is 7.5G-15G, the ball-material ratio is 15: 1-30: 1, and the ball milling time is 120 min-240 min; the particle size range of the activated nickel sulfide concentrate after ball milling is that D50 is less than or equal to 15 mu m.

3. The comprehensive utilization method according to claim 1, wherein in the step S20, the leaching solution is sulfuric acid solution, the dosage of the sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.20-0.40 mL/g, the gas introduced into the leaching solution is oxygen, the introduction flow rate of the oxygen is 0.6-1.0L/min, the leaching time of the activated nickel sulfide concentrate is 240-360 min, the leaching temperature is 80-100 ℃, and the end-point pH value in the leaching process is 1-3.

4. The integrated utilization method according to claim 1, wherein, in the step S30, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the leachate of the nickel sulfide concentrate is 3g/L to 5 g/L.

5. The comprehensive utilization method according to claim 1, wherein the step S40 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;

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

6. The comprehensive utilization method according to claim 1, wherein the step S50 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.

7. The comprehensive utilization method according to claim 6, wherein in step S50, the temperature of the constant-temperature water bath is 70 ℃ to 100 ℃, and the predetermined pH value is 4 to 5; and the excess coefficient of the amount of the sodium fluoride is 1.25-2.0 based on the amount of the magnesium ions and the calcium ions in the second solution which are completely precipitated.

8. The comprehensive utilization method according to claim 1, wherein in said step S60,

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.

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

10. The comprehensive utilization method according to claim 1, wherein the step S80 specifically includes:

adding a 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 performing solid-liquid separation after the reaction 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.

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 applied to the fields of aerospace, military and civil industries due to 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 metal nickel of 332+333 grade is proved, and 21.77 million tons (average grade of 0.166%) of 333 grade copper resource and 3.81 million tons (average grade of 0.025%) of cobalt resource are associated, so that the ultra-large magma copper-nickel sulfide ore deposit becomes 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 the 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 the nickel sulfate so as to reduce the pollution of the nickel sulfate 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 ball mill for ball milling treatment, and performing mechanical activation treatment on the nickel sulfide concentrate to form activated nickel sulfide concentrate;

s20, placing the activated nickel sulfide concentrate into a leaching solution, introducing gas into the leaching solution to form micro bubbles, and stirring to leach metal elements in the activated nickel sulfide concentrate to obtain a nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements;

s30, 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;

s40, 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;

s50, 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;

s60, 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 to obtain a loaded organic phase and a nickel-containing raffinate after extraction is finished;

s70, 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;

s80, preparing and obtaining a nickel sulfate product by taking the nickel-containing raffinate as a raw material.

Preferably, the process conditions of the ball milling treatment in the step S10 include: the ball milling strength is 7.5G-15G, the ball-material ratio is 15: 1-30: 1, and the ball milling time is 120 min-240 min; the particle size range of the activated nickel sulfide concentrate after ball milling is that D50 is less than or equal to 15 mu m.

Preferably, in the step S20, the leaching solution is a sulfuric acid solution, the usage amount of the sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.20mL/g to 0.40mL/g, the gas introduced into the leaching solution is oxygen, the introduction flow rate of the oxygen is 0.6L/min to 1.0L/min, the leaching time of the activated nickel sulfide concentrate is 240min to 360min, the leaching temperature is 80 ℃ to 100 ℃, and the end-point pH in the leaching process is 1 to 3.

Preferably, in the step S30, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the leachate of the nickel sulfide concentrate is 3g/L to 5 g/L.

Preferably, the step S40 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, in the step S40, the predetermined temperature is 70 ℃ to 100 ℃, the gas flow rate of introducing oxygen into the first solution is 0.8L/min to 1.2L/min, and the reaction time is 300min to 500 min; and controlling the pH value to be 3-4 in the reaction process.

Preferably, the step S50 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, in the step S50, the temperature of the constant-temperature water bath is 70 ℃ to 100 ℃, and the predetermined pH value is 4 to 5; and the excess coefficient of the amount of the sodium fluoride is 1.25-2.0 based on the amount of the magnesium ions and the calcium ions in the second solution which are completely precipitated.

Preferably, in the step S60,

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 S70 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 S80 specifically includes:

adding a 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 performing solid-liquid separation after the reaction 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, the nickel sulfide concentrate is pretreated by mechanical activation, so that the reaction activity of the nickel sulfide concentrate is improved, and micro-bubbles are introduced to enhance oxidation and control leaching and precipitation behaviors of iron in the leaching process, so that the selective leaching of the nickel sulfide concentrate under the normal pressure condition is realized; then, removing iron ions and copper ions in the leachate of the nickel sulfide ore by a goethite method, thereby solving the influence of the iron ions with higher concentration on the recovery process flow and energy consumption of the nickel; finally, other metal impurities in the leachate are sequentially subjected to impurity removal, nickel sulfate is prepared to recycle nickel elements, and the extracted and separated cobalt elements are further utilized by preparing cobalt sulfate. Therefore, the method not only realizes the high-efficiency utilization of the nickel element in the nickel sulfide concentrate leachate, but also further recycles other metal elements, is beneficial to improving the resource utilization rate and the utilization value 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 results of the effect of the shot-to-shot ratio on leaching of activated nickel sulfide concentrate in example 1 of the present invention;

FIG. 3 is a graph showing the results of the effect of ball milling strength (G value) on leaching of activated nickel sulfide concentrate in example 1 of the present invention;

FIG. 4 is a graph showing the results of the effect of ball milling time on leaching of activated nickel sulfide concentrate in example 1 of the present invention;

FIG. 5 is a graph showing the effect of end point pH on leaching of activated nickel sulfide concentrate in the leaching process of example 1 of the present invention;

FIG. 6 is a graph showing the effect of sulfuric acid dosage on leaching of activated nickel sulfide concentrate in example 1 of the present invention;

FIG. 7 is a graph showing the relationship between the amount of iron powder added and the concentration of copper ions in the process of replacing copper ions by reducing iron powder in the leachate of nickel sulfide concentrate according to example 2 of the present invention;

fig. 8 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. 9 is an X-ray diffraction (XRD) pattern of the iron slag in example 2 of the present invention;

FIG. 10 is a graph showing the relationship between the end point pH 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. 11 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. 12 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 step S10, placing the nickel sulfide concentrate into a ball mill for ball milling treatment, and performing mechanical activation treatment on the nickel sulfide concentrate to form activated nickel sulfide concentrate.

Preferably, the process conditions of the ball milling treatment include: the ball milling strength is 7.5G-15G, the ball-material ratio is 15: 1-30: 1, and the ball milling time is 120 min-240 min; the particle size range of the activated nickel sulfide concentrate after ball milling is that D50 is less than or equal to 15 mu m.

Further preferably, the ball milling strength is 10G, the ball-to-material ratio is 20:1, and the ball milling time is 180 min.

The ball milling medium is formed by mixing stainless steel grinding balls or zirconium grinding balls with different diameters, and the diameters and the corresponding masses of the grinding balls are respectively as follows:(0.5kg)，(0.5kg)，(0.25kg)。

by adopting mechanical activation to pretreat the nickel sulfide concentrate, the mineral structure of the nickel sulfide concentrate is destroyed, and the reaction activity of the nickel sulfide concentrate is improved, thereby being beneficial to improving the leaching efficiency of metal elements in the nickel sulfide concentrate.

And step S20, placing the activated nickel sulfide concentrate into leaching solution, introducing gas into the leaching solution to form micro bubbles, and stirring to leach metal elements in the activated nickel sulfide concentrate to obtain nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements.

Preferably, the leaching solution is a sulfuric acid solution, the dosage of the sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.20-0.40 mL/g, the gas introduced into the leaching solution is oxygen, the introduction flow rate of the oxygen is 0.6-1.0L/min, the leaching time of the activated nickel sulfide concentrate is 240-360 min, the leaching temperature is 80-100 ℃, and the end point pH value in the leaching process is 1-3.

Further preferably, the usage amount of the sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/g, the gas introduced into the leaching solution is oxygen, the introduction flow rate of the oxygen is 0.8L/min, the leaching time of the activated nickel sulfide concentrate is 300min, and the leaching temperature is 90 ℃.

Preferably, the stirring is carried out by mechanical stirring, and the stirring speed is 200rpm to 400 rpm.

Magnetic stirring or mechanical stirring can be selected as the stirring mode, but the influence of the dynamic condition on the leaching process is obvious, and the phenomena of insufficient stirring dynamics, incomplete stirring and the like exist in the magnetic stirring process, so that the mechanical stirring is favorable for enhancing the dynamics of the reaction process and improving the leaching efficiency of metal elements in the leaching process.

According to the invention, on the basis of mechanical activation treatment of the nickel sulfide concentrate, microbubble is introduced to enhance oxidation to control leaching and precipitation of iron in the leaching process, so that selective and efficient leaching of the nickel sulfide concentrate under normal pressure is realized, and leaching of iron is inhibited.

And step S30, 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 5 g/L.

Further preferably, the amount of the fine reduced iron is added so that the concentration of the fine reduced iron in the leachate of the nickel sulfide concentrate is 3.88 g/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 step S40, 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.

Preferably, the step S40 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.

Goethite is one of the main minerals containing hydrous oxides, generally called alpha-form monohydrated iron oxide, and its composition is alpha-Fe₂O₃·H₂O or alpha-FeOOH, the precipitates of which have a high iron content and are soluble in solutionOther metal ions are less adsorbed, so that the recovery rate of the metallic iron can be higher by adopting the goethite method.

The specific reaction process of goethite method iron removal comprises oxidation reaction and hydrolysis reaction:

and (3) oxidation reaction:

4Fe²⁺+O₂+4H⁺→4Fe³⁺+2H₂O

and (3) hydrolysis reaction:

Fe³⁺+H₂O→FeOH²⁺+H⁺

FeOH²⁺+H₂O→FeOOH+2H⁺

oxygen first Fe²⁺Oxidation to Fe³⁺，Fe³⁺Forming simple hydrolysate FeOH through hydrolysis²⁺The hydrolysate is further hydrolyzed to generate FeOOH microcrystals, the FeOOH microcrystals are aggregated and grown to form goethite type solid precipitate alpha-FeOOH, wherein Fe²⁺Oxidation and Fe³⁺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; and controlling the pH value to be 3-4 in the reaction process.

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 480 min.

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 Fe³⁺Are extremely unstable in solution and therefore Fe³⁺FeOH is generated by hydrolysis reaction²⁺Is very fast. But if Fe is in solution³⁺Content is too high (>1g/L), Fe is easily caused³⁺Formation of Fe (OH)₃Colloidal precipitation, and therefore, in the process of removing iron by the goethite process, the key is to control Fe²⁺The invention adopts a microbubble oxidation method to oxidize Fe²⁺Controlling the flow of oxygen to control Fe²⁺Oxidation process of (2) toSolves the problem of difficult iron removal control in the goethite method.

In the process of removing iron by goethite method, Fe²⁺Oxidation rate of ion and [ H ]⁺]^0.25Inversely proportional, Fe in solution with increasing pH²⁺Has an increased oxidation rate of Fe³⁺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 oxidation³⁺The ion concentration is more than 1g/L, which is easy to cause Fe³⁺Rapidly precipitate and form Fe (OH)₃Colloid, 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 step S50, 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, performing solid-liquid separation to obtain a liquid-phase third solution.

Preferably, the step S50 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.

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

Ca²⁺+2F^-→CaF₂↓，K_sp＝2.7×10^-11

Mg²⁺+2F^-→MgF₂↓，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; and the excess coefficient of the amount of the sodium fluoride is 1.25-2.0 based on the amount of the magnesium ions and the calcium ions in the second solution which are 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^-The ions are excessive and new impurities are generated.

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 Ca²⁺、Mg²⁺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 Ca²⁺、Mg²⁺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 step S60, 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 S60 specifically includes:

and S601, 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 ratio is 1: 1-2: 1, 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.

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 1:1, the extraction temperature is 25 ℃, the extraction time is 10min, the standing time is 10min, and the pH in the reaction process is controlled to be 3.5.

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

Step S602, performing extraction and separation of cobalt ions with the extraction organic phase containing the P507 extraction agent to the impurity-removed third solution:

preparing an extraction organic phase containing a P507 extraction agent, taking the impurity-removed 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 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 ratio is 1.5: 1-3: 1, 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.

Further preferably, the volume fraction of the P507 extracting agent in the extracted organic phase is 25%, the saponification rate of the P507 extracting agent is 70%, the extraction phase ratio is 2:1, the extraction temperature is 25 ℃, the extraction time is 10min, the standing time is 10min, and the pH value in the reaction process is controlled to be 3.25.

And step S70, carrying out back extraction on the loaded organic phase to obtain cobalt-containing back extraction liquid, and preparing cobalt sulfate products by taking the cobalt-containing back extraction liquid as a raw material.

Preferably, the step S70 specifically includes:

and step S701, washing the loaded organic phase by using a sulfuric acid solution with the concentration of 0.1-0.4 mol/L.

And S702, 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 S703, heating, evaporating and concentrating the cobalt sulfate solution, and then 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 2 h.

And step S80, preparing and obtaining a nickel sulfate product by taking the nickel-containing raffinate as a raw material.

Preferably, the S80 specifically includes:

step S801, adding a sodium hydroxide solution into the nickel-containing raffinate, and after the reaction is finished, performing solid-liquid separation 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 S802, 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 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 nickel in the nickel sulfate solution is 100 g/L.

And S803, heating, evaporating and concentrating the nickel sulfate solution, and then cooling and crystallizing to prepare the 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 the comprehensive utilization of a nickel sulfide concentrate 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 the comprehensive utilization of a nickel sulfide concentrate of 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 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

Step one, placing the nickel sulfide concentrate into a ball mill for ball milling treatment, and performing mechanical activation treatment on the nickel sulfide concentrate to form activated nickel sulfide concentrate.

And step two, placing the activated nickel sulfide concentrate into a sulfuric acid solution, introducing oxygen into the sulfuric acid solution to form micro bubbles, and stirring to leach metal elements in the activated nickel sulfide concentrate to obtain a nickel sulfide concentrate leachate, wherein the metal elements at least comprise copper, iron, cobalt, nickel, magnesium and calcium elements.

(1) Investigating the influence of ball material ratio on preparing nickel sulfide concentrate leaching solution

Wherein the reaction conditions are selected as follows: the ball milling strength is 10G, the ball milling time is 180min, the dosage of a sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/G, the introduction flow of oxygen is 0.8L/min, the magnetic stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 300min, and the leaching temperature is 90 ℃; the leaching of the activated nickel sulfide concentrate under the conditions of ball-to-material ratios of 10:1, 15:1, 20:1, 25:1 and 30:1 is respectively considered. Fig. 2 is a graph showing the effect of shot ratio on leaching of activated nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 2.

As can be seen from FIG. 2, the leaching efficiency of Ni, Co and Cu is gradually increased with the increase of the ball-to-material ratio, while the leaching efficiency of Fe is reduced from 50% to 42% when the ball-to-material ratio is increased from 10:1 to 15:1, and then the leaching efficiency of Fe is kept basically unchanged by continuously increasing the ball-to-material ratio. When the ball-to-feed ratio is 20:1, the leaching rates of nickel, cobalt, copper and iron are 96.1%, 95.6%, 92.2% and 43.7%, respectively. In conclusion, the ball-to-material ratio is preferably 15: 1-30: 1; when the ball-material ratio is 20: when 1, the metal selective leaching effect of the activated nickel sulfide concentrate is the best.

(2) Investigating the influence of the ball milling strength (G value) on the preparation of the nickel sulfide concentrate leaching solution

Wherein the reaction conditions are selected as follows: the ball milling time is 180min, the ball-to-material ratio is 20:1, the dosage of the sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/g, the introduction flow of oxygen is 0.8L/min, the magnetic stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 300min, and the leaching temperature is 90 ℃; the leaching of the activated nickel sulfide concentrate under the conditions of 5G, 7.5G, 10G, 12.5G and 15G of ball milling strength (G value) is respectively considered. Fig. 3 is a graph showing the effect of ball milling strength (G value) on leaching of activated nickel sulfide 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 of keeping other experimental conditions unchanged, when the ball milling strength is increased from the 5G value to the 10G value, the leaching rates of nickel, cobalt and copper are increased from 72.4%, 45.2% and 76.6% to 96.1%, 94.75% and 92.15%, the ball milling strength is continuously increased, the leaching rates of nickel, cobalt and copper are not increased basically, and the leaching rates of iron are reduced and then tend to be balanced along with the increase of the ball milling strength. In summary, the ball milling strength (G value) is preferably 7.5G-15G, and when the ball milling strength is 10G value, the metal selective leaching effect of the activated nickel sulfide concentrate is the best.

(3) Investigating the influence of the ball milling time on the preparation of the nickel sulfide concentrate leaching solution

Wherein the reaction conditions are selected as follows: the ball milling strength is 10G, the ball-to-material ratio is 20:1, the dosage of a sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/G, the introduction flow of oxygen is 0.8L/min, the magnetic stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 300min, the leaching temperature is 90 ℃, and the leaching of the activated nickel sulfide concentrate under the conditions that the ball milling time is 60min, 120min, 180min and 240min is respectively considered. Fig. 4 is a graph showing the results of the effect of ball milling time on leaching of activated nickel sulphide concentrate, and the experimental results obtained under the above conditions are shown in fig. 4.

As can be seen from fig. 4, the ball milling time has no significant effect on leaching of the activated nickel sulfide concentrate under the condition that other experimental conditions are kept unchanged, and as the ball milling time is increased from 60min to 240min, the leaching rates of nickel, cobalt and copper in the nickel sulfide concentrate are increased from 88.3%, 79.1% and 76.2% to 97.8%, 95.3% and 93.4%, while the leaching of iron is not substantially affected by the ball milling time. Therefore, in view of the above, the ball milling time is preferably 120min to 240min, and 180min is most preferably selected.

(4) Investigating the influence of the end point pH value of the leaching process on the preparation of the nickel sulfide concentrate leaching solution

Wherein the reaction conditions are selected as follows: the ball milling strength is 10G, the ball-material ratio is 20:1, the ball milling time is 180min, the oxygen introduction flow rate is 1L/min, the magnetic stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 300min, the leaching temperature is 80 ℃, and the leaching of the activated nickel sulfide concentrate is respectively considered under the condition that an ammonia water solution with the initial concentration of 1mol/L and an ammonium sulfate solution with the initial concentration of 1mol/L are adopted as leaching solutions. Figure 5 is a graph showing the effect of end point pH on activated nickel sulphide concentrate leaching in the leaching process, and the experimental results obtained under the above conditions are shown in figure 5.

As can be seen from FIG. 5The ammonia water solution with the initial concentration of 1mol/L and the ammonium sulfate solution with the initial concentration of 1mol/L are adopted as leaching solution, the initial pH of the leaching solution is 8.5, but the pH of the leaching solution is gradually reduced along with the progress of the reaction and is finally acidic, because S in activated sulfide ore is oxidized into sulfuric acid along with the continuous oxidation of oxygen in the leaching process, and OH in the solution is consumed^-The generation amount of the sulfuric acid is increased along with the continuous reaction of the ions, so that the solution is gradually in an acidic system. When the pH value of the end point of the reaction is 4.2, the leaching rates of nickel, cobalt, copper and iron in the nickel sulfide concentrate are all less than 10 percent; the leaching rates of nickel, cobalt and copper are gradually increased along with the reduction of the end point pH, and when the end point pH is 2.8, the leaching rates of nickel, cobalt and copper are 82.5%, 81.9% and 48.5% respectively, and the leaching rate of iron is only 9.7% at the moment; when the end point pH continued to decrease to 1.0, the leaching rates for nickel and cobalt did not change substantially and the leaching rates for copper and iron increased rapidly. Therefore, in order to ensure the leaching efficiency of inhibiting iron in the leaching process and improve the leaching efficiency of nickel, cobalt and copper, the pH value of the end point of the leaching process needs to be controlled to be 1-3.

(5) Influence of sulphuric acid dosage on preparation of nickel sulphide concentrate leachate

Wherein the reaction conditions are selected as follows: the ball milling strength is 7.5G, the ball-to-material ratio is 15:1, the ball milling time is 120min, the flow rate of oxygen is 0.6L/min, the magnetic stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 240min, and the leaching of the activated nickel sulfide concentrate under the condition that the sulfuric acid dosage is increased from 0.075ml/G to 0.30ml/G is respectively considered under the condition that the leaching temperature is 70 ℃. Fig. 6 is a graph showing the effect of the amount of sulfuric acid on leaching of activated nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 6.

As can be seen from FIG. 6, the dosage of sulfuric acid is increased from 0.075ml/g to 0.30ml/g, the pH value at the end point of the leaching process is between 1.5 and 2.5, and at this time, the leaching rate of nickel and cobalt is less changed with the increase of the dosage of sulfuric acid, while the leaching rate of iron is increased from 19.3% to 48.2%, and the leaching rate of copper is increased from 49.2% to 71.8%, therefore, the dosage of sulfuric acid is preferably 0.2ml/g to 0.4ml/g, and the dosage of sulfuric acid is selected as 0.3ml/g to be optimal, considering the leaching efficiency of nickel, cobalt and copper and the leaching efficiency of iron.

(6) 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 ball milling strength is 10G, the ball-to-material ratio is 20:1, the ball milling time is 180min, the dosage of a sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/G, the introduction flow of oxygen is 0.8L/min, the mechanical stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 300min, the end-point pH value of the leaching process is 2.5, and the leaching of the activated nickel sulfide concentrate under the conditions that the leaching temperature is 60 ℃, 70 ℃, 80 ℃ and 90 ℃ is respectively inspected. Table 3 shows the effect of leaching temperature on leaching efficiency of activated nickel sulphide concentrate, and the experimental results obtained under the above conditions are shown in table 3.

Table 3: influence of leaching temperature on leaching efficiency of activated nickel sulfide concentrate

Leaching temperature/. degree.C	Co	Cu	Fe	Ni
					60	80％	78％	65％	80％
70	85％	85％	47％	85％
					80	93％	91％	39％	93％
90	95.5％	92.35％	36.74％	97.05％

As can be seen from table 3, when the leaching temperature is increased from 60 ℃ to 90 ℃, the leaching rates of nickel, cobalt and copper are increased and the leaching rate of iron is decreased as the leaching temperature is increased, so that the leaching efficiency of nickel, cobalt and copper and the leaching efficiency of iron are considered together, the preferred range of the leaching temperature is 80 ℃ to 100 ℃, and the optimal leaching temperature is selected to be 90 ℃.

On the other hand, the mechanical stirring is adopted in the stirring mode in the experimental part, and compared with the magnetic stirring mode adopted in other experimental parts in the examples, under the same conditions, the leaching rates of nickel, cobalt and copper are improved, and the leaching rate of iron is greatly reduced, so the mechanical stirring mode is preferably adopted.

(7) Investigating the influence of leaching time on the preparation of nickel sulfide concentrate leachate

Wherein the reaction conditions are selected as follows: the ball milling strength is 10G, the ball-to-material ratio is 20:1, the ball milling time is 180min, the dosage of a sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/G, the introduction flow of oxygen is 0.8L/min, the mechanical stirring speed is 300rpm, the leaching temperature of the activated nickel sulfide concentrate is 90 ℃, the end-point pH value of the leaching process is 2.5, and the leaching of the activated nickel sulfide concentrate is respectively considered under the conditions that the leaching time is 60min, 120min, 180min, 240min, 300min and 360 min. Table 4 shows the effect of leaching time on leaching efficiency of activated nickel sulphide concentrate, and the experimental results obtained under the above conditions are shown in table 4.

Table 4: influence of leaching time on leaching efficiency of activated nickel sulfide concentrate

Leaching time/min	Co	Cu	Fe	Ni
					60	58％	74％	51％	70％
120	74％	65％	48％	81％
					180	85％	78％	46％	89％
240	93％	88％	44％	94％
					300	95.5％	92.35％	36.37％	97.05％
360	95％	91％	35％	97％

As can be seen from table 4, when the leaching time is increased from 60min to 300min, the leaching efficiency of cobalt is increased from 58% to 95.5%, the leaching efficiency of copper is increased from 74% to 92.35%, the leaching efficiency of nickel is increased from 70% to 97.05%, and the leaching efficiency of iron is decreased from 51% to 36.37%, and then the leaching time is increased from 300min to 360min, the leaching efficiency of nickel, cobalt, copper and iron has no significant change, therefore, in summary, the leaching time is preferably 240min to 360min, and the leaching time is optimally selected to be 300 min.

(8) Investigating the influence of oxygen flow on the preparation of nickel sulfide concentrate leachate

Wherein the reaction conditions are selected as follows: the ball milling strength is 10G, the ball-to-material ratio is 20:1, the ball milling time is 180min, the dosage of a sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/G, the mechanical stirring speed is 300rpm, the leaching temperature of the activated nickel sulfide concentrate is 90 ℃, the leaching time is 300min, the end-point pH value of the leaching process is 2.5, and the leaching of the activated nickel sulfide concentrate under the conditions that the introduction flow of oxygen is 0.4L/min, 0.8L/min and 1.0L/min is respectively considered. Table 5 shows the effect of oxygen flow on the leaching efficiency of the activated nickel sulphide concentrate, and the experimental results obtained under the above conditions are shown in table 5.

Table 5: influence of oxygen flow on leaching efficiency of activated nickel sulfide concentrate

Oxygen flow (L/min)	Co	Cu	Fe	Ni
					0.4	73％	62％	49％	79％
0.8	95.5％	92.35％	36.74％	97.05％
					1.0	96％	93％	33％	98％

As can be seen from Table 5, when the oxygen flow rate is increased from 0.4L/min to 0.8L/min, the leaching efficiency of cobalt is increased from 73% to 95.5%, the leaching efficiency of copper is increased from 62% to 92.35%, the leaching efficiency of nickel is increased from 79% to 97.05%, and the leaching efficiency of iron is decreased from 49% to 36.37%, and then the oxygen flow rate is increased from 0.8L/min to 1.0L/min, the leaching efficiency of nickel, cobalt, copper and iron has no significant change, therefore, in summary, the oxygen flow rate is preferably 0.6L/min to 1.0L/min, and the oxygen flow rate is optimally selected to be 0.8L/min.

In summary, the optimized process conditions for preparing the leaching solution of the nickel sulfide concentrate are as follows: the ball milling strength is 10G, the ball-to-material ratio is 20:1, the ball milling time is 180min, the dosage of a sulfuric acid solution relative to the activated nickel sulfide concentrate is 0.30mL/G, the introduction flow of oxygen is 0.8L/min, the mechanical stirring speed is 300rpm, the leaching time of the activated nickel sulfide concentrate is 300min, the leaching temperature is 90 ℃, and the end-point pH value of the leaching process is 2.5.

And under the optimized process conditions, after the leaching reaction of the activated nickel sulfide concentrate is finished, filtering the activated 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 respectively 97.05%, 95.5%, 92.35% and 36.74%, 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 introduced into the leaching solution is 1L/min, and the reaction time is 480 min.

(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. 7 is a graph showing the relationship between the amount of iron powder added and the concentration of copper ions in the process of replacing copper ions by reducing iron powder in the leachate of nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 7.

As can be seen from fig. 7, 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, and therefore 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 5.0 g/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 3.88 g/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 3.88 g/L.

Fig. 8 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. 8.

As can be seen from fig. 8, 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 pH of the reaction is further increased to 5, the removal efficiency of iron ions is substantially maintained, but the ion removal rate of nickel ions and cobalt ions is sharply increased, and the ion loss rate thereof is sharply increased. This is due to Fe²⁺Oxidation rate of [ H ]⁺]^0.25Inversely proportional, Fe in solution with increasing pH²⁺Accelerated oxidation of ions, Fe³⁺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 generated by oxidation because the pH is too high³⁺The ion concentration is more than 1g/L, resulting in Fe³⁺Rapidly precipitate and form Fe (OH)₃The colloid adsorbs a large amount of nickel ions and cobalt ions, 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 in the reaction process of controlling the microbubble oxidation method to generate goethite type precipitates is optimally controlled to be 3-4.

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 3.88 g/L; the reaction process of forming goethite type precipitate by a microbubble oxidation method comprises the following steps: the flow rate 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 480 min.

Under the optimized process conditions, after the reaction is finished, solid-liquid separation is carried out to obtain iron slag precipitate and nickel sulfide concentrate leaching solution with copper ions and iron ions removed.

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 6.

Table 6: full element semi-quantitative analysis of iron slag (XRF)

As is clear from Table 6, 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 7.

Table 7: quantitative analysis (ICP-OES) of main metal elements in iron slag and analysis of leachate components

As can be seen from table 7, 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 0.012 g/L.

FIG. 9 is an X-ray diffraction (XRD) pattern of the iron slag, and it can be seen from FIG. 9 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. 10 is a graph showing the relationship between the end point pH 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. 10.

As can be seen from fig. 10, 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 conclusion, the end point pH value is preferably 4-5, and when the end point pH value is 4.5, the effect of removing calcium ions and magnesium ions in the nickel sulfide concentrate leachate is the best.

(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 1.5 h; 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. 11 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. 11.

As can be seen from fig. 11, 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. In summary, the reaction temperature is preferably 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. 12 is a graph showing the relationship between the excess factor of the amount of sodium fluoride 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. 12.

As can be seen from fig. 12, 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 removal efficiency of calcium and magnesium is not obviously increased by continuously increasing the dosage of sodium fluoride, and F in the solution can be caused^-The ions are excessive and new impurities are generated. 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 the embodiment 3, namely the leachate without magnesium ions and calcium ions as an extraction water phase, removing impurities through an extraction process, and separating after extraction is finished to obtain a third solution after impurities are removed, namely the leachate without trace copper, iron and aluminum metal impurities.

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 1:1, the extraction temperature is 25 ℃, the extraction time is 10min, the standing time is 10min, and the pH value in the reaction process is controlled to be 3.5.

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 impurity-removed third solution as an extraction water phase, extracting and separating cobalt ions through an extraction process, and separating to obtain a loaded organic phase and a nickel-containing raffinate after extraction is finished, 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 2:1, the extraction temperature is 25 ℃, the extraction time is 10min, the standing time is 10min, and the pH value in the reaction process is controlled to be 3.25.

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, back-extracting 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 time of back extraction 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 2 h.

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 4 h.

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 100 g/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 ℃, controlling the pH value in the reaction process to be 3.5-3.6, and preparing the nickel sulfate product.

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

According to the invention, the nickel sulfide concentrate is pretreated by mechanical activation, so that the reaction activity of the nickel sulfide concentrate is improved, and microbubbles are introduced to enhance oxidation to control leaching and precipitation behaviors of iron in the leaching process, so that the valuable metals of nickel, cobalt and copper in the nickel sulfide concentrate are efficiently leached under normal pressure, the leaching of iron is inhibited, and the leaching rates of nickel, cobalt, copper and iron in the nickel sulfide concentrate are respectively 97.1%, 95.5%, 92.4% and 36.7%. Then, the goethite method is adopted for removing iron, so that iron ions in the nickel sulfide ore leaching solution can be removed efficiently, the influence of iron ions with higher concentration on the recovery process flow and energy consumption of nickel is solved, iron slag and sponge copper obtained by reaction can be sold directly, and the utilization value of raw materials is favorably improved. And finally, removing impurities from metal impurities in the nickel sulfide concentrate leachate in sequence, and preparing a cobalt sulfate product and a nickel sulfate product to recycle cobalt elements and nickel elements. Therefore, 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 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.