阅读说明：本技术 一种硫化镍精矿的超细磨-氧压浸出工艺 (Superfine grinding-oxygen pressure leaching process for nickel sulfide concentrate ) 是由 孙峙 谢小平 蔡楠 党电邦 李青春 魏国 湛金 李鹏 谈伟军 于 2021-06-18 设计创作，主要内容包括：本发明提供了一种超细磨-氧压浸出工艺,所述工艺包括：将硫化镍精矿与溶剂混合调浆,以形成预定浓度的硫化镍精矿料浆；将所述硫化镍精矿料浆进行球磨,形成超细磨硫化镍精矿；将所述超细磨硫化镍精矿置于反应炉中并加入浸取液,向所述浸取液中通入预定压力的氧气,以浸出所述超细磨硫化镍精矿中的金属元素。所述工艺通过对硫化镍精矿进行细磨预处理,减少了硫化镍精矿的颗粒粒度,提高了比表面积,从而提高了硫化镍精矿的反应活性,有利于在浸出过程中降低氧压浸出温度和氧压浸出能耗,从而实现了硫化镍精矿的常压选择性高效浸出。(The invention provides a superfine grinding-oxygen pressure leaching process, which comprises the following steps: mixing and pulping the nickel sulfide concentrate and a solvent to form nickel sulfide concentrate slurry with a preset concentration; ball-milling the nickel sulfide concentrate slurry to form ultra-fine milled nickel sulfide concentrate; and placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding leaching solution, and introducing oxygen with preset pressure into the leaching solution to leach metal elements in the superfine grinding nickel sulfide concentrate. The process reduces the particle size of the nickel sulfide concentrate and improves the specific surface area by finely grinding the nickel sulfide concentrate, thereby improving the reaction activity of the nickel sulfide concentrate, being beneficial to reducing the oxygen pressure leaching temperature and the oxygen pressure leaching energy consumption in the leaching process and realizing the normal-pressure selective high-efficiency leaching of the nickel sulfide concentrate.)

1. An ultra-fine grinding-oxygen pressure leaching process of nickel sulfide concentrate is characterized by comprising the following steps of:

s10, size mixing: mixing and pulping the nickel sulfide concentrate and a solvent to form nickel sulfide concentrate slurry with a preset concentration;

s20, fine grinding: ball-milling the nickel sulfide concentrate slurry to form ultra-fine milled nickel sulfide concentrate; the mass ratio of the mineral aggregate with the granularity of below 300 meshes in the superfine grinding nickel sulfide concentrate is more than 90 percent;

s30, leaching: and placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding leaching solution, and introducing oxygen with preset pressure into the leaching solution to leach metal elements in the superfine grinding nickel sulfide concentrate.

2. The leaching process according to claim 1, wherein in the step S10, the solvent is water, and the concentration of the nickel sulfide concentrate slurry is 20-30%.

3. The process of leaching according to claim 2, wherein the concentration of the nickel sulphide concentrate slurry is 25%.

4. The leaching process of claim 1, wherein in step S20, the nickel sulfide concentrate slurry is ball milled in a ball mill to form ultra-fine milled nickel sulfide concentrate; the mass ratio of the mineral aggregate with the granularity of below 400 meshes in the superfine grinding nickel sulfide concentrate is more than 90 percent.

5. The leaching process according to claim 1, wherein in the step S30, the leaching solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 50 g/L-100 g/L, and the solid-to-liquid ratio of the ultra-fine ground nickel sulfide concentrate to the sulfuric acid solution is 100 g/L-300 g/L.

6. The leaching process according to claim 5, wherein the concentration of the sulfuric acid solution is 50g/L, and the solid-to-liquid ratio of the ultra-fine ground nickel sulfide concentrate to the sulfuric acid solution is 200 g/L.

7. The leaching process according to claim 1, wherein the predetermined pressure is 0.8Mpa to 1.4Mpa in the step S30.

8. The process of leaching according to claim 7, wherein the predetermined pressure is 1.4 Mpa.

9. The leaching process according to any one of claims 1 to 8, wherein in the step S30, the leaching temperature is 110 ℃ to 160 ℃ and the leaching time is 100min to 300 min.

10. The leaching process according to claim 9, wherein the leaching temperature is 110 ℃ and the leaching time is 300 min.

Technical Field

The invention belongs to the technical field of nickel sulfide concentrate treatment, and particularly relates to a superfine grinding-oxygen pressure leaching process 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.

Common treatment methods for nickel ores include pyrometallurgical processes and hydrometallurgical processes. The hydrometallurgical process comprises a high-pressure ammonia leaching method, a sulfating roasting leaching method, a high-pressure acid leaching method, a chlorination leaching method and the like, wherein the high-pressure acid leaching technology is mature, but the methods have the characteristics of high treatment energy consumption, large equipment investment, high treatment cost, low treatment efficiency, possibility of generating secondary pollution and the like. The main stream treatment process of the existing nickel sulfide ore is a pyrometallurgical process, wherein the pyrometallurgical process adopts a high-temperature matte smelting method to convert the nickel sulfide ore into low grade nickel matte, then blowing is carried out to obtain high grade nickel matte, and then a high-pressure leaching method is adopted to extract nickel. Therefore, the research and development of a new process which is low in temperature, clean and capable of efficiently extracting the nickel element in the nickel sulfide concentrate becomes a bottleneck problem which needs to be solved urgently by a plurality of enterprises.

Disclosure of Invention

In view of the defects of the prior art, the invention provides an ultra-fine grinding-oxygen pressure leaching process for nickel sulfide concentrate, which aims to solve the problems of high leaching temperature, high energy consumption, low selective leaching efficiency of valuable metals and the like in the existing treatment process for nickel sulfide concentrate.

In order to achieve the above object, the present invention provides a superfine grinding-oxygen pressure leaching process of nickel sulfide concentrate, comprising:

s10, size mixing: mixing and pulping the nickel sulfide concentrate and a solvent to form nickel sulfide concentrate slurry with a preset concentration;

s20, fine grinding: carrying out ball milling on the nickel sulfide ore slurry to form superfine milled nickel sulfide ore; the mass ratio of ore material with the granularity of below 300 meshes in the superfine grinding nickel sulfide ore is more than 90 percent;

s30, leaching: and placing the superfine grinding nickel sulfide ore into a reaction furnace, adding leaching liquid, and introducing oxygen with preset pressure into the leaching liquid to leach metal elements in the superfine grinding nickel sulfide ore.

Preferably, in the step S10, the solvent is water, and the concentration of the nickel sulfide ore slurry is 20% -30%.

Further preferably, the concentration of the nickel sulphide concentrate slurry is 25%.

Preferably, in the step S20, the nickel sulfide concentrate slurry is placed in a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; the mass ratio of the mineral aggregate with the granularity of below 400 meshes in the superfine grinding nickel sulfide concentrate is more than 90 percent.

Preferably, in the step S30, the leaching solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 50g/L to 100g/L, and the solid-to-liquid ratio of the ultra-fine ground nickel sulfide concentrate to the sulfuric acid solution is 100g/L to 300 g/L.

Further preferably, the concentration of the sulfuric acid solution is 50g/L, and the solid-to-liquid ratio of the ultra-fine ground nickel sulfide concentrate to the sulfuric acid solution is 200 g/L.

Preferably, in the step S30, the predetermined pressure is 0.8Mpa to 1.4 Mpa.

Further preferably, the predetermined pressure is 1.4 Mpa.

Preferably, in the step S30, the leaching temperature is 110 to 160 ℃, and the leaching time is 100 to 300 min.

Further preferably, the leaching temperature is 110 ℃ and the leaching time is 300 min.

According to the superfine grinding-oxygen pressure leaching process for the nickel sulfide concentrate, provided by the invention, the nickel sulfide concentrate is pretreated by adopting a mechanical activation means, and before leaching, the nickel sulfide concentrate is subjected to superfine grinding pretreatment, so that the particle size of the nickel sulfide concentrate is reduced, the specific surface area is increased, the reaction activity of the nickel sulfide concentrate is improved, the reduction of the oxygen pressure leaching temperature and the oxygen pressure leaching energy consumption in the leaching process is facilitated, the normal-pressure selective and efficient leaching of the nickel sulfide concentrate at a lower temperature is realized, and the problems of high leaching temperature, high energy consumption, lower valuable metal selective leaching efficiency and the like in the treatment process of the nickel sulfide concentrate are solved.

Drawings

FIG. 1 is a flow chart of a process for ultra-fine grinding-oxygen pressure leaching of nickel sulfide concentrate according to an embodiment of the present invention;

FIG. 2 is a graph showing the effect of the fine grinding particle size on the leaching of the ultra-fine ground nickel sulfide concentrate in example 1 of the present invention;

FIG. 3 is a graph showing the effect of sulfuric acid concentration on leaching of ultra-fine milled nickel sulfide concentrate in example 2 of the present invention;

FIG. 4 is a graph showing the effect of oxygen pressure on the leaching of ultra-fine ground nickel sulfide concentrate in example 3 of the present invention;

FIG. 5 is an XRD pattern of the leached residue in example 6 of the present invention;

FIG. 6 is an SEM-EDS analysis chart of leached residues in example 6 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 an ultra-fine grinding-oxygen pressure leaching process of nickel sulfide concentrate, and with reference to figure 1, the process comprises the following steps:

step S10, size mixing: the nickel sulfide concentrate is mixed with a solvent and slurried to form a nickel sulfide concentrate slurry of a predetermined concentration.

Preferably, the solvent is water, and the concentration of the nickel sulfide ore slurry is 20-30%.

Further preferably, the concentration of the nickel sulphide concentrate slurry is 25%.

Step S20, fine grinding: and carrying out ball milling on the nickel sulfide ore slurry to form superfine milled nickel sulfide ore.

Preferably, the mass ratio of the mineral aggregate with the granularity of less than 300 meshes in the superfine grinding nickel sulfide ore is more than 90 percent.

Preferably, the mass ratio of the mineral aggregate with the granularity of below 400 meshes in the superfine grinding nickel sulfide concentrate is above 90%.

The fine grinding pretreatment is carried out on the nickel sulfide concentrate, so that the granularity of reactant particles of the nickel sulfide concentrate can be reduced, the specific surface area of the reactant particles is improved, and the reaction activity of the nickel sulfide concentrate is improved.

Step S30, leaching: and placing the superfine grinding nickel sulfide ore into a reaction furnace, adding leaching liquid, and introducing oxygen with preset pressure into the leaching liquid to leach metal elements in the superfine grinding nickel sulfide ore.

Preferably, the leaching solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 50 g/L-100 g/L, and the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 100 g/L-300 g/L.

Further preferably, the concentration of the sulfuric acid solution is 50g/L, and the solid-to-liquid ratio of the ultra-fine ground nickel sulfide concentrate to the sulfuric acid solution is 200 g/L.

Preferably, the predetermined pressure is 0.8Mpa to 1.4 Mpa.

Further preferably, the predetermined pressure is 1.4 Mpa.

Preferably, the leaching temperature is 110-160 ℃, and the leaching time is 100-300 min.

Further preferably, the leaching temperature is 110 ℃, and the leaching time is 300 min.

The activity of reactants of the nickel sulfide concentrate is improved through fine grinding pretreatment, the oxygen pressure leaching temperature of the nickel sulfide concentrate is reduced in the leaching process, and the energy consumption of the oxygen pressure leaching is reduced, so that the normal-pressure selective leaching of the nickel sulfide concentrate is realized.

The above ultra-fine grinding-oxygen pressure leaching process of the 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 ultra-fine grinding-oxygen pressure leaching process of the above 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: XRF elemental analysis of nickel sulfide concentrate

Example 1: effect of Fine grind size on Leaching

Step one, size mixing: the nickel sulfide concentrate is mixed with water and slurried to form a 25% concentration slurry of nickel sulfide concentrate.

Step two, fine grinding: and placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with the concentration of 100g/L as a leaching solution, and introducing oxygen with the pressure of 1.4Mpa into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the leaching temperature is 110 ℃, and the leaching time is 300 min.

Under the conditions, the influence of different fine grinding particle sizes on the leaching of the metal elements of the ultra-fine grinding nickel sulfide concentrate is respectively inspected; when the ball milling time is 3min, the mass ratio of ore material with the granularity of below 300 meshes of the superfine milling nickel sulfide concentrate is more than 90 percent; when the ball milling time is 6min, the mass ratio of the ore material with the granularity of below 400 meshes of the superfine milling nickel sulfide concentrate is more than 90 percent.

Fig. 2 is a graph showing the effect of fine grinding particle size on leaching of the ultra-fine ground nickel sulfide 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 rates of nickel, cobalt and copper of the nickel sulfide concentrate which is not subjected to the fine grinding pretreatment are obviously lower than those of the nickel sulfide concentrate which is subjected to the fine grinding pretreatment; when the mass ratio of the mineral aggregate with the granularity of less than 300 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent, the leaching rates of nickel, cobalt and copper are 97 percent, 98.8 percent and 64.5 percent; continuously reducing the particle size to the mineral aggregate with the particle size below-400 meshes by mass ratio of more than 90 percent, wherein the leaching rates of nickel, cobalt and copper are 97.7 percent, 99.8 percent and 78.3 percent, and the leaching efficiency of iron is basically unchanged; therefore, when the ball milling time is 6min and the mass ratio of the mineral aggregate with the granularity of below-400 meshes is more than 90%, the metal selective leaching effect of the nickel sulfide concentrate is the best.

Example 2: effect of sulfuric acid concentration on Leaching

Step one, size mixing: the nickel sulfide concentrate is mixed with water and slurried to form a 25% concentration slurry of nickel sulfide concentrate.

Step two, fine grinding: placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; wherein, the ball milling time is 6min, and the mass ratio of the ore material with the granularity of below 400 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with a preset concentration as a leaching solution, and introducing oxygen with the pressure of 1.4Mpa into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the leaching temperature is 110 ℃, and the leaching time is 300 min.

Under the conditions, the influence of different sulfuric acid concentrations on the leaching of metal elements in the superfine grinding nickel sulfide concentrate is respectively examined.

Fig. 3 is a graph showing the effect of sulfuric acid concentration on the leaching of the ultra-fine milled 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 that other experimental conditions are kept unchanged, when no sulfuric acid is added, the leaching efficiencies of nickel, cobalt, copper and iron are 44%, 29.3%, 35.3% and 29.9%, respectively; when the concentration of the sulfuric acid is 50g/L, the leaching rates of nickel, cobalt, copper and iron are 96.8%, 99.5%, 74.9% and 30.4%; the concentration of the sulfuric acid is continuously increased, the leaching rates of nickel, cobalt and copper are basically unchanged, and the leaching rate of iron is in an increasing trend; therefore, the concentration of the sulfuric acid solution is preferably 50g/L to 100g/L in comprehensive consideration, and when the concentration of the sulfuric acid solution is selected to be 50g/L in order to avoid excessive leaching of iron, the metal selective leaching effect of the ultra-fine ground nickel sulfide concentrate is the best.

Example 3: effect of oxygen pressure on leaching

Step one, size mixing: the nickel sulfide concentrate is mixed with water and slurried to form a 25% concentration slurry of nickel sulfide concentrate.

Step two, fine grinding: placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; wherein, the ball milling time is 6min, and the mass ratio of the ore material with the granularity of below 400 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with the concentration of 50g/L as a leaching solution, and introducing oxygen with preset pressure into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the leaching temperature is 110 ℃, and the leaching time is 300 min.

Under the conditions, the influence of oxygen pressure of 0.8Mpa and 1.4Mpa on the leaching of metal elements in the superfine grinding nickel sulfide concentrate is respectively examined.

Fig. 4 is a graph showing the effect of oxygen pressure on the leaching of the ultra-fine milled nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in fig. 4.

As can be seen from fig. 4, under the condition that other experimental conditions are kept unchanged, along with the increase of the pressure of the introduced oxygen from 0.8Mpa to 1.4Mpa, the leaching rates of nickel and cobalt in the nickel sulfide concentrate are both obviously increased, the leaching rate of copper is not obviously changed, and the leaching rate of iron is reduced, so that the leaching of nickel and cobalt can be improved while the leaching of iron is inhibited by increasing the oxygen pressure, and the selective leaching of valuable elements is realized; in view of the above, it is preferable to select the oxygen pressure of 1.4 MPa.

Example 4: influence of leaching temperature

Step one, size mixing: the nickel sulfide concentrate is mixed with water and slurried to form a 25% concentration slurry of nickel sulfide concentrate.

Step two, fine grinding: placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; wherein, the ball milling time is 6min, and the mass ratio of the ore material with the granularity of below 400 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with the concentration of 50g/L as a leaching solution, and introducing oxygen with the pressure of 1.4Mpa into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 200g/L, and the leaching time is 300 min.

Under the conditions, the influence of different leaching temperature conditions on the leaching of the metal elements in the superfine grinding nickel sulfide concentrate is respectively considered.

Table 3 shows the effect of leaching temperature on the leaching efficiency of the metal elements in the ultra-fine milled nickel sulfide 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 metal elements in superfine grinding nickel sulfide concentrate

Leaching temperature/. degree.C	Co	Cu	Fe	Ni
					110	99.5	74.9	30.4	96.8
140	99.9	83.4	75.4	98.5
					160	99.9	88.9	97.7	99.9

As can be seen from table 3, when the leaching temperature is increased from 110 ℃ to 160 ℃, the leaching efficiency of cobalt and nickel is not changed significantly with the increase of the leaching temperature, but the leaching efficiency of iron is continuously increased, so that the leaching temperature is selected to be the optimal temperature of 110 ℃ by comprehensively considering the leaching effects of nickel, cobalt, copper and iron, thereby ensuring the efficient leaching of nickel, cobalt and copper in the nickel sulfide concentrate and simultaneously inhibiting the leaching of iron.

Example 5: influence of solid-to-liquid ratio

Step one, size mixing: the nickel sulfide concentrate is mixed with water and slurried to form a 25% concentration slurry of nickel sulfide concentrate.

Step two, fine grinding: placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; wherein, the ball milling time is 6min, and the mass ratio of the ore material with the granularity of below 400 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with the concentration of 50g/L as a leaching solution, and introducing oxygen with the pressure of 1.4Mpa into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the leaching temperature is 110 ℃, and the leaching time is 300 min.

Under the conditions, the influence of different solid-liquid ratios of the superfine grinding nickel sulfide concentrate and the sulfuric acid solution on the leaching of metal elements in the superfine grinding nickel sulfide concentrate is respectively inspected.

Table 4 shows the influence of the solid-liquid ratio of the ultra-fine milled nickel sulfide concentrate to the sulfuric acid solution on the leaching efficiency of the metal elements in the ultra-fine milled nickel sulfide concentrate, and the experimental results obtained under the above conditions are shown in table 4.

Table 4: influence of solid-liquid ratio on leaching efficiency of metal elements in the superfine grinding nickel sulfide concentrate

Solid to liquid ratio (g/L)	Co	Cu	Fe	Ni
					100	99.8	86.7	53.2	99.9
200	99.5	74.9	30.4	96.8
					300	85.6	70.3	39.8	89.5

As can be seen from Table 4, when the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is increased from 100g/L to 200g/L, the leaching efficiency of cobalt and nickel is not obviously changed, the leaching efficiency of copper is reduced from 86.7% to 74.9%, and the leaching efficiency of iron is reduced from 53.2% to 30.4%; and increasing the solid-liquid ratio from 200g/L to 300g/L, the leaching efficiency of nickel, cobalt and copper is reduced, and the leaching efficiency of iron is slightly increased, so that the leaching effect of nickel, cobalt, copper and iron in the nickel sulfide concentrate is comprehensively considered, and the solid-liquid ratio is optimal to 200 g/L.

Example 6: examples of optimal Process parameters

By combining the process conditions of the above embodiments, the optimized process conditions of the superfine grinding-oxygen pressure leaching process of the nickel sulfide concentrate can be obtained.

Step one, size mixing: the nickel sulfide concentrate is mixed with water and slurried to form a 25% concentration slurry of nickel sulfide concentrate.

Step two, fine grinding: placing the nickel sulfide concentrate slurry into a ball mill for ball milling to form ultra-fine milled nickel sulfide concentrate; wherein, the ball milling time is 6min, and the mass ratio of the ore material with the granularity of below 400 meshes of the superfine grinding nickel sulfide concentrate is more than 90 percent.

Step three, leaching: placing the superfine grinding nickel sulfide concentrate into a reaction furnace, adding a sulfuric acid solution with the concentration of 50g/L as a leaching solution, and introducing oxygen with the pressure of 1.4Mpa into the sulfuric acid solution to leach metal elements in the superfine grinding nickel sulfide concentrate; wherein the solid-to-liquid ratio of the superfine grinding nickel sulfide concentrate to the sulfuric acid solution is 200g/L, the leaching temperature is 110 ℃, and the leaching time is 300 min.

Under the conditions, the leaching efficiencies of nickel, cobalt, copper and iron in the ultra-fine grinding nickel sulfide concentrate are 96.8%, 99.5%, 74.9% and 30.4% respectively.

And after the leaching reaction of the superfine grinding nickel sulfide concentrate is finished, filtering the superfine grinding nickel sulfide concentrate to obtain leaching slag and filtrate.

FIG. 5 is an XRD spectrum of the leaching residue, and from FIG. 5, it can be seen that the main phases of the leaching residue are FeO (OH), elemental S and Mg₃Si₄O₁₀(OH)₂。

Table 5 shows the leaching residue elemental analysis (XRF) of the leaching residue.

Table 5: leaching residue elemental analysis (XRF)

As can be seen from Table 5, the main elements in the leached residues are: the S content is 10.07%, the Fe content is 42.34%, and the Mg content is 2.11%, and the Mg leaching efficiency can be calculated to be 51.2% according to the quality of the leaching slag of the Mg content before and after leaching.

FIG. 6 is an SEM-EDS analysis diagram of the leaching residue, and it can be seen from FIG. 6 that the elemental S in the leaching residue exists mainly in the form of small particles without wrapping phenomenon, so that the elemental S phase in the leaching residue can be separated by flotation.

According to the superfine grinding-oxygen pressure leaching process provided by the invention, nickel sulfide concentrate is pretreated by adopting a mechanical activation means, and before leaching, the nickel sulfide concentrate is subjected to superfine grinding pretreatment, so that the particle size of the nickel sulfide concentrate is reduced, the specific surface area is increased, the reaction activity of the nickel sulfide concentrate is improved, the reduction of the oxygen pressure leaching temperature and the oxygen pressure leaching energy consumption in the leaching process is facilitated, the normal-pressure selective efficient leaching of the nickel sulfide concentrate at a lower temperature is realized, the problems of high leaching temperature, high energy consumption, lower valuable metal selective leaching efficiency and the like in the traditional oxygen pressure leaching technology are solved, and the problem of serious secondary pollution in the leaching process is solved. After the leaching reaction is finished, the obtained elemental S in the leaching slag mainly exists in a small particle form without a wrapping phenomenon, and the elemental S phase in the leaching slag can be separated in a flotation mode, so that the problem that the elemental S in the leaching slag is difficult to separate is solved.

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.