阅读说明：本技术 一种利用硫化铜镍矿尾矿制备氢氧化镁联产硅微粉的方法 (Method for preparing magnesium hydroxide and coproducing silicon micropowder by using copper-nickel sulfide ore tailings ) 是由 潘爱芳 马昱昭 孙悦 马润勇 于 2021-10-13 设计创作，主要内容包括：本发明涉及一种利用硫化铜镍矿尾矿制备氢氧化镁联产硅微粉的方法,步骤为：S1、将硫化铜镍矿尾矿和氢氧化钠/碳酸钠1:0.6-1.5混合,研磨至200-300目,制得混合生料；S2、将混合生料焙烧,得到活性熟料,同时收集焙烧炉气；S3、将活性熟料用水浸出得到水浸渣和水浸液；S4、向水浸液通二氧化碳进行碳酸化分解,固液分离得到硅胶和碳酸钠溶液；S5、将炉气充分燃烧并用水收集得到硫酸溶液,将硫酸溶液调至2-5mol/L,对水浸渣进行酸浸,得滤渣和滤液A；S6、将滤液A加热陈化,得到硅胶和滤液B；S7、将S4和S6的硅胶合并,在120-200℃下干燥得二氧化硅微粉；S8、调节滤液B的pH至9.4-12.4,得到氢氧化镁和滤液C。本发明利用硫化铜镍矿尾矿为原料制取微硅粉和氢氧化镁等产品,实现了对硫化铜镍矿尾矿的高附加值利用。(The invention relates to a method for preparing magnesium hydroxide and coproducing silicon micropowder by using copper-nickel sulfide ore tailings, which comprises the following steps: s1, mixing the tailings of the copper-nickel sulfide ore with sodium hydroxide/sodium carbonate at a ratio of 1:0.6-1.5, and grinding to 200-300 meshes to prepare a mixed raw material; s2, roasting the mixed raw material to obtain active clinker, and collecting roasting furnace gas; s3, leaching the active clinker with water to obtain water leaching slag and water leaching solution; s4, introducing carbon dioxide into the water extract for carbonation decomposition, and performing solid-liquid separation to obtain silica gel and a sodium carbonate solution; s5, fully burning the furnace gas, collecting the furnace gas with water to obtain a sulfuric acid solution, adjusting the sulfuric acid solution to 2-5mol/L, and performing acid leaching on the water leaching slag to obtain filter residue and filtrate A; s6, heating and aging the filtrate A to obtain silica gel and filtrate B; s7, combining the silica gels of S4 and S6, and drying at the temperature of 120-200 ℃ to obtain silicon dioxide micropowder; s8, adjusting the pH value of the filtrate B to 9.4-12.4 to obtain magnesium hydroxide and filtrate C. The invention utilizes the tailings of the copper-nickel sulfide ore as the raw material to prepare the products such as the micro-silicon powder, the magnesium hydroxide and the like, thereby realizing the high value-added utilization of the tailings of the copper-nickel sulfide ore.)

1. A method for preparing magnesium hydroxide and coproducing silicon micropowder by utilizing tailings of copper-nickel sulfide ores is characterized by comprising the following steps:

s1, mixing the copper-nickel sulfide ore tailings and the auxiliary agent according to the mass ratio of 1:0.6-1.5, and grinding to 200-300 meshes to prepare a mixed raw material; the auxiliary agent is sodium hydroxide or sodium carbonate;

s2, roasting the mixed raw material of S1 at normal pressure to obtain active clinker, and collecting furnace gas generated in the roasting process;

s3, mixing the active clinker generated by roasting the S2 with water, stirring, leaching and filtering to obtain water leaching slag and water leaching liquid; the water leaching solution contains water-soluble silicate;

s4, slowly introducing carbon dioxide gas into the water extract obtained in the step S3 for carbonation decomposition, and performing solid-liquid separation to obtain silica gel and Na₂CO₃Filtering, adding Na₂CO₃Concentrating the filtrate, and then applying the concentrated filtrate to S1 as an auxiliary agent for wet-process burdening;

s5, performing dust removal and purification on furnace gas generated in the step S2 through a dust remover, cooling, fully burning, collecting and dissolving a combustion product with water to obtain a sulfuric acid solution, adjusting the concentration of the sulfuric acid solution to 2-5mol/L, mixing the sulfuric acid solution with water leaching slag generated in the step S3, stirring, dissolving and filtering to obtain filter residue and filtrate A; the filter residue contains metal salt which is insoluble in sulfuric acid solution; the filtrate A contains metal salts dissolved in sulfuric acid solution, including silicate insoluble in alkali liquor and soluble in sulfuric acid;

s6, heating and aging the filtrate A, and carrying out solid-liquid separation to obtain silica gel and a filtrate B, wherein the filtrate B is a desiliconized metal salt solution;

s7, combining the silica gels obtained in the steps S4 and S6, washing with water until the pH value is close to 7, and drying at the temperature of 120-;

s8, removing impurities from the filtrate B, and adjusting the pH value of the filtrate B to 9.4-12.4 to obtain magnesium hydroxide and filtrate C.

2. The method as claimed in claim 1, wherein the calcination temperature in S2 is 600-950 ℃ and the calcination time is 20-60 min.

3. The method according to claim 1, wherein in S3, the ratio of active clinker to water is 1: 5-15 mixing; the temperature of agitation leaching is 25-90 ℃, and the agitation time is 5-30 min.

4. The method of claim 1, wherein the carbonation decomposition reaction is terminated at a point where the aqueous leach solution has a pH of 6 to 8 at S4.

5. The method according to claim 1, wherein the sulfuric acid concentration in S5 is adjusted by: concentrated sulfuric acid is added/concentrated by evaporation to increase the concentration of the sulfuric acid solution or diluted with water to decrease the concentration of the sulfuric acid solution.

6. The method according to claim 1, wherein in S5, the sulfuric acid solution and the water leached slag are mixed according to a solid-liquid mass ratio of 1: 5-10.

7. The method according to claim 1, wherein in S5, the temperature for stirring and dissolving is 25-90 ℃, and the stirring time is 3-20 min.

8. The method as claimed in claim 1, wherein in S6, the temperature for heating and aging filtrate A is 25-90 deg.C, and the aging time is 1.5-10 h.

9. The method according to claim 1, wherein in S7, the mixture of silica gel and water in a mass ratio of 1:2-5 is washed with water to a pH value of about 7; drying at 170 ℃, and ball-milling to obtain the silica micropowder.

10. The method according to claim 1, wherein in S8, the pH of the filtrate B is slowly adjusted by using a sodium hydroxide solution with a mass concentration of 5-20%, iron ions and aluminum ions in the solution are removed, and finally magnesium hydroxide is prepared.

Technical Field

The invention belongs to the technical field of comprehensive utilization of mine solid wastes, and particularly relates to a method for preparing magnesium hydroxide and co-producing silicon micropowder by utilizing copper-nickel sulfide ore tailings.

Background

The copper-nickel sulfide ore is continuously mined and utilized as a main nickel ore resource in China, but the existing mineral separation process only recovers part of target minerals, and the proportion of the copper-nickel sulfide ore is difficult to separate and dilute is continuously increased, so that a large amount of tailings are generated after the copper-nickel sulfide ore is subjected to mineral separation, and the tailings of the copper-nickel sulfide ore contain a large amount of components such as magnesium, iron, sulfur, nickel and the like, so that serious resource waste and environmental pollution are caused (Roxianping et al, 2013; Liangdong Mei et al, 2009; Xijie et al, 2018). Taking the example of the copper-nickel mineral from Jinchuan, the production amount of tailings exceeds 700 million tons/day, the accumulated stockpiling amount exceeds 2.7 hundred million tons, and the occupied area exceeds 8km²The method causes serious pollution to the air and soil in the stockpiled land, and the stockpiled land contains a large amount of valuable components such as magnesium, chromium, nickel and the like, thereby causing serious resource waste (Huang Neng, 2014). The existing recovery process (wet leaching, flotation and heavy-flotation) for the tailings of the copper-nickel sulfide ore has the defects of large slag discharge amount, serious environmental pollution and comprehensive recoveryLow utilization rate and the like. Therefore, in order to solve the problems of environmental pollution, resource waste, land occupation and the like of the tailings of the copper-nickel sulfide ore in China and realize harmless utilization and high value-added utilization of the tailings of the copper-nickel sulfide ore in China, a method for efficiently recycling the tailings of the copper-nickel sulfide ore is urgently needed to be developed.

Disclosure of Invention

Technical problem to be solved

In view of the defects and shortcomings of the prior art, the invention provides a method for preparing magnesium hydroxide and co-producing silicon micropowder by utilizing tailings of copper-nickel sulfide ores, which can convert silicon in the tailings of copper-nickel sulfide ores into silicon micropowder and can extract magnesium from the tailings of copper-nickel sulfide ores to convert the magnesium into magnesium hydroxide. The method of the invention recovers the sulfur in the tailings and prepares the sulfuric acid, and the sulfuric acid is used for the acid leaching step, thereby reducing the acid cost and avoiding the problem of sulfur emission pollution.

(II) technical scheme

In order to achieve the purpose, the invention adopts the main technical scheme that:

in a first aspect, the invention provides a method for preparing magnesium hydroxide and coproducing silicon micropowder by using tailings of copper-nickel sulfide ores, which comprises the following steps:

s1, mixing the copper-nickel sulfide ore tailings and the auxiliary agent according to the mass ratio of 1:0.6-1.5, and grinding to 200-300 meshes to prepare a mixed raw material; the auxiliary agent is sodium hydroxide or sodium carbonate;

s2, roasting the mixed raw material of S1 at normal pressure to obtain active clinker, and collecting furnace gas generated in the roasting process;

s3, mixing the active clinker generated by roasting the S2 with water, stirring, leaching and filtering to obtain water leaching slag and water leaching liquid; the water leaching solution contains water-soluble silicate;

s4, slowly introducing carbon dioxide gas into the water extract obtained in the step S3 for carbonation decomposition, and performing solid-liquid separation to obtain silica gel and Na₂CO₃Filtering, adding Na₂CO₃Concentrating the filtrate, and then applying the concentrated filtrate to S1 as an auxiliary agent for wet-process burdening;

s5, performing dust removal and purification on furnace gas generated in the step S2 through a dust remover, cooling, fully burning, collecting and dissolving a combustion product with water to obtain a sulfuric acid solution, adjusting the concentration of the sulfuric acid solution to 2-5mol/L, mixing the sulfuric acid solution with water leaching slag generated in the step S3, stirring, dissolving and filtering to obtain filter residue and filtrate A; the filter residue contains metal salt which is insoluble in sulfuric acid solution; the filtrate A contains metal salts dissolved in sulfuric acid solution, including silicate insoluble in alkali liquor and soluble in sulfuric acid;

s6, heating and aging the filtrate A, and carrying out solid-liquid separation to obtain silica gel and a filtrate B, wherein the filtrate B is a desiliconized metal salt solution;

s7, combining the silica gels obtained in the steps S4 and S6, washing with water until the pH value is close to 7, and drying at the temperature of 120-;

s8, removing impurities from the filtrate B, and adjusting the pH value of the filtrate B to 9.4-12.4 to obtain magnesium hydroxide and filtrate C.

According to the preferred embodiment of the invention, in S2, the baking temperature is 600-950 ℃, and the baking time is 20-60 min.

According to the preferred embodiment of the invention, in S3, the ratio of the active clinker to the water is 1: 5-15, and mixing.

According to the preferred embodiment of the invention, in S3, the agitation leaching temperature is 25-90 ℃, and the agitation time is 5-30 min.

According to the preferred embodiment of the present invention, the end point of the carbonation decomposition reaction in S4 is that the pH value of the aqueous leach solution reaches 6-8.

According to the preferred embodiment of the present invention, in S5, the method for adjusting the sulfuric acid concentration comprises: concentrated sulfuric acid is added/concentrated by evaporation to increase the concentration of the sulfuric acid solution or diluted with water to decrease the concentration of the sulfuric acid solution.

According to the preferred embodiment of the invention, in S5, the sulfuric acid solution and the water leaching slag are mixed according to the solid-liquid mass ratio of 1: 5-10.

According to the preferred embodiment of the present invention, in S5, the temperature for stirring and dissolving is 25-90 deg.C, and the stirring time is 3-20 min.

According to the preferred embodiment of the present invention, in S6, the temperature for heating and aging filtrate A is 25-90 deg.C, and the aging time is 1.5-10 h.

According to the preferred embodiment of the invention, in S7, silica gel and water are mixed according to the mass ratio of 1:2-5 for water washing until the pH value is close to 7; drying at 170 ℃, and ball-milling to obtain the silica micropowder.

In S8, dilute sodium hydroxide solution is used to slowly adjust the pH of the filtrate B to remove iron ions and aluminum ions in the solution, and finally magnesium hydroxide is obtained. The mass concentration of the sodium hydroxide solution is 5-20%.

Wherein the pH range of the ferric hydroxide precipitate is 1.5-4.1, the pH range of the aluminum hydroxide precipitate is 3.3-5.2, and the magnesium hydroxide precipitate is obtained when the pH value is 9.4-12.4.

(III) advantageous effects

(1) The invention provides a method for preparing magnesium hydroxide and coproducing silicon micropowder by utilizing tailings of copper-nickel sulfide ores, which takes the tailings of copper-nickel sulfide ores as raw materials, and comprises the steps of activating roasting, dissolving out water and acid step by step, carbonating and decomposing water extract to obtain silica gel, heating and aging acid extract to obtain silica gel and desiliconized metal salt solution; thereby recovering silicon in the tailings of the copper-nickel sulfide ores and converting the silicon into silicon micropowder products, and adjusting the pH of the desiliconized metal salt solution by using dilute alkali solution to obtain magnesium hydroxide products. The sulfur in the tailings is recycled to prepare sulfuric acid when the active clinker is prepared, so that the acid cost and the sulfur emission are reduced, and the economic benefit is considerable. After the sodium carbonate solution obtained after the carbonation decomposition of the water leaching solution is concentrated, the sodium carbonate solution is used as an activating auxiliary agent for blending by a wet method, so that the cost of the auxiliary agent is reduced.

(2) Compared with the prior art of flotation, gravity separation-flotation, direct acid leaching and the like, the method has the advantages of high comprehensive utilization rate and no environmental pollution.

(3) The method has the advantages of simple process, no special requirement on equipment, low energy consumption, easy realization of industrialization and the like, the sulfur element is converted into sulfuric acid to be directly applied to the process as the source of acid in the acid leaching solution, the method meets the environmental protection requirement (no toxic and harmful solid waste is discharged, and no toxic and harmful solution and gas such as acidity, alkalinity, heavy metal and the like are discharged), and a new way is opened up for the high-efficiency resource utilization of the tailings of the copper-nickel sulfide ore.

Drawings

Fig. 1 is a general flow chart of a method for preparing magnesium hydroxide and co-producing silicon micropowder by using tailings of copper-nickel sulfide ores provided by the invention.

Detailed Description

For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.

As shown in figure 1, the invention provides a method for preparing magnesium hydroxide and co-producing silicon micropowder by using tailings of copper-nickel sulfide ores, which comprises the following steps:

s1, mixing the copper-nickel sulfide ore tailings and the auxiliary agent according to the mass ratio of 1:0.6-1.5, and grinding to 200-300 meshes to prepare a mixed raw material; the auxiliary agent is sodium hydroxide or sodium carbonate.

S2, roasting the mixed raw material of S1 at the high temperature of 600-950 ℃ for 20-60min under normal pressure to obtain active clinker, and collecting furnace gas generated in the roasting process.

S3, mixing the active clinker generated by roasting S2 and water according to the solid-liquid mass ratio of 1: 5-15, stirring and leaching at 25-90 deg.C for 5-30min, and filtering to obtain water leaching residue and water leaching solution. The water extract contains water-soluble silicate, mainly sodium silicate.

S4, slowly introducing carbon dioxide gas into the water extract in the step S3 for carbonation decomposition, stopping introducing the carbon dioxide when the pH value of the water extract reaches 6-8, and performing solid-liquid separation to obtain silica gel and Na₂CO₃Filtering, adding Na₂CO₃Concentrating the filtrate, and then applying the concentrated filtrate to S1 as an auxiliary agent for wet batching.

S5, performing dust removal and purification on furnace gas generated in S2 through a dust remover, cooling, fully burning, collecting and dissolving a combustion product with water to obtain a sulfuric acid solution, adjusting the concentration of the sulfuric acid solution to 2-5mol/L, mixing the sulfuric acid solution with water leaching slag generated in S3 according to the solid-liquid mass ratio of 1:5-10, stirring for 3-20min at 25-90 ℃ to promote dissolution, and filtering after acid leaching to obtain filter residue and filtrate A; the filter residue contains metal salt which is insoluble in sulfuric acid solution and other solid residue (insoluble in water and insoluble in dilute sulfuric acid); the filtrate A contains metal salts dissolved in sulfuric acid solution (part of metal hydroxides and dilute sulfuric acid are subjected to acid-base neutralization and are dissolved in the dilute sulfuric acid), including silicates insoluble in alkali liquor and soluble in sulfuric acid (some water-insoluble silicates react with the dilute sulfuric acid to generate silicic acid and soluble sulfates).

The method for adjusting the concentration of the sulfuric acid comprises the following steps: adding concentrated sulfuric acid/evaporating concentration to increase the concentration of the sulfuric acid solution or adding water for dilution to reduce the concentration of the sulfuric acid solution, and finally obtaining the dilute sulfuric acid solution with the concentration of 2-5 mol/L.

S6, heating the filtrate A to 25-90 ℃, aging for 1.5-10h, and carrying out solid-liquid separation to obtain silica gel and filtrate B, wherein the filtrate B is a desiliconized metal salt solution. Heating and aging to separate silicic acid from the filtrate A in the form of silica gel.

S7, combining the silica gel obtained in the steps S4 and S6, washing the silica gel with water until the pH value is close to 7, and drying the silica gel at the temperature of 120-200 ℃, preferably at the temperature of 170 ℃ to obtain the silicon dioxide micro powder. Specifically, the method comprises the steps of mixing silica gel and water according to the mass ratio of 1:2-5, washing with water until the pH value is close to 7, drying at 170 ℃ for 5-10h, and performing ball milling to obtain the silica micropowder. The other method is to mix and pulp silica gel and water with the mass ratio of 1:2-5, and then dry the mixture by adopting a spray drying method to obtain the silicon dioxide micro powder.

The silicon dioxide micropowder has the advantages of good temperature resistance, acid and alkali corrosion resistance, poor thermal conductivity, high insulation, low expansion, stable chemical performance and the like, and can be used in the fields of electronics, integrated circuits, refractory materials, electricity, plastics, coatings, high-grade paint, rubber and the like.

S8, removing impurities from the filtrate B, and adjusting the pH value of the filtrate B to 9.4-12.4 to obtain magnesium hydroxide and filtrate C. And specifically, the pH of the filtrate B is slowly adjusted by adopting a sodium hydroxide solution with the mass concentration of 5-20%, iron ions and aluminum ions in the solution are removed, and finally the magnesium hydroxide is prepared. Slowly dropping sodium hydroxide solution, stirring, measuring pH, standing, precipitating iron at pH 1.5-4.1, precipitating aluminum at pH 3.3-5.2, and precipitating magnesium hydroxide at pH 9.4-12.4.

Magnesium hydroxide is an inorganic flame-retardant material with excellent performance, can be used as a flame retardant, an acidic wastewater neutralizer, a heavy metal wastewater precipitator, a flue gas desulfurizer, cosmetics, food additives and the like, and is also an important raw material for producing magnesium oxide. Especially when used as an inorganic flame retardant, the flame retardant has the advantages of high decomposition temperature, strong smoke suppression capability, good flame retardant effect, no toxic or corrosive substances generated after decomposition and the like, and is an excellent inorganic flame retardant product.

The following are specific examples of the present invention.

Example 1

SiO in tailings of copper-nickel sulfide ore₂40.69% of Fe, 31.71% of MgO₂O₃The content of Al is 13.02 percent₂O₃The content of SO is 4.24%₃The content is 3.48%.

The embodiment provides a method for preparing magnesium hydroxide and coproducing silicon micropowder by using copper-nickel sulfide ore tailings, which comprises the following steps:

s1, mixing the copper-nickel sulfide ore tailings and sodium carbonate according to the mass ratio of 1:1.5, and grinding to 200 meshes to obtain a mixed raw material.

S2, roasting the mixed raw material of S1 at the high temperature of 780 ℃ for 60min under normal pressure to obtain active clinker, and collecting furnace gas generated in the roasting process.

S3, mixing the active clinker generated by roasting S2 and water according to the solid-liquid mass ratio of 1:5 mixing, leaching at 90 deg.C for 5min under stirring, and filtering to obtain water leaching residue and water leaching solution. The water extract contains sodium silicate.

S4, slowly introducing carbon dioxide gas into the water extract in the step S3 for carbonation decomposition, stopping introducing the carbon dioxide when the pH value of the water extract reaches 6.0, and performing solid-liquid separation to obtain silica gel and Na₂CO₃Filtering, adding Na₂CO₃Concentrating the filtrate, and then applying the concentrated filtrate to S1 as an auxiliary agent for wet batching.

S5, performing dust removal and purification on furnace gas generated in S2 through a dust remover, cooling, fully burning, collecting and dissolving combustion products with water to obtain a sulfuric acid solution, adjusting the concentration of the sulfuric acid solution to 5mol/L, mixing the sulfuric acid solution with water leaching slag generated in S3 according to the solid-liquid mass ratio of 1:5, stirring and leaching at 50 ℃ for 5min, and filtering to obtain filter residue and filtrate A; the filter residue contains metal salt which is insoluble in sulfuric acid solution and other solid residue (insoluble in water and insoluble in dilute sulfuric acid); the filtrate A contains metal salts dissolved in sulfuric acid solution (part of metal hydroxides and dilute sulfuric acid are subjected to acid-base neutralization and are dissolved in the dilute sulfuric acid), including silicates insoluble in alkali liquor and soluble in sulfuric acid (some water-insoluble silicates react with the dilute sulfuric acid to generate silicic acid and soluble sulfates).

The method for adjusting the concentration of the sulfuric acid comprises the following steps: adding concentrated sulfuric acid/evaporating concentration to increase the concentration of the sulfuric acid solution or adding water for dilution to reduce the concentration of the sulfuric acid solution, and finally obtaining the dilute sulfuric acid solution with the concentration of 2-5 mol/L.

S6, heating the filtrate A to 90 ℃, aging for 2h, and carrying out solid-liquid separation to obtain silica gel and filtrate B, wherein the filtrate B is a desiliconized metal salt solution. Heating and aging to separate silicic acid from the filtrate A in the form of silica gel.

S7, combining the silica gel obtained in the steps S4 and S6, mixing the silica gel and water according to the mass ratio of 1:2, pulping, and spray-drying at 125 ℃ to obtain the silicon dioxide micropowder.

And S8, slowly adjusting the pH value of the filtrate B by using a sodium hydroxide solution with the mass concentration of 5%, slowly dripping the sodium hydroxide solution into the filtrate B, measuring the pH value after stirring, standing the filtrate B after the preset pH value is reached, precipitating iron and aluminum in the range of pH value of 1.5-5.2, filtering and centrifuging the iron hydroxide and the aluminum hydroxide to remove the iron hydroxide and the aluminum hydroxide, and continuously dripping the sodium hydroxide solution into the filtrate B to obtain magnesium hydroxide precipitate at the pH value of 9.4-12.4.

The method of the embodiment recovers the sulfur in the tailings of the copper-nickel sulfide ore and prepares sulfuric acid, the sulfuric acid is used for an acid leaching step, the acid cost is reduced, the problem of sulfur emission pollution is avoided, and Si in the tailings of the copper-nickel sulfide ore is recovered and prepared into a product of silica fume, wherein the silica fume is a refractory material and a filler with wide application (such as plastic, high-grade paint, coating or rubber). The method of the embodiment also recovers Mg in the tailings of the copper-nickel sulfide ores to prepare a magnesium hydroxide product, and the magnesium hydroxide is an excellent smokeless flame retardant, a flue gas desulfurizer, a cosmetic/food additive and the like. Therefore, the method can utilize the copper-nickel sulfide ore tailings with high added value, and change waste into valuable.

Example 2

SiO in tailings of copper-nickel sulfide ore₂40.69% of Fe, 31.71% of MgO₂O₃The content of Al is 13.02 percent₂O₃The content of SO is 4.24%₃The content is 3.48%.

The embodiment provides a method for preparing magnesium hydroxide and coproducing silicon micropowder by using copper-nickel sulfide ore tailings, which comprises the following steps:

s1, mixing the copper-nickel sulfide ore tailings and sodium hydroxide according to the mass ratio of 1:0.6, and grinding to 200 meshes to obtain a mixed raw material.

S2, roasting the mixed raw material of S1 at the high temperature of 950 ℃ for 30min under normal pressure to obtain active clinker, and collecting furnace gas generated in the roasting process.

S3, mixing the active clinker generated by roasting S2 and water according to the solid-liquid mass ratio of 1:15, stirring and leaching at 30 ℃ for 20min, and filtering to obtain water leaching residues and water leaching solution. The water extract contains sodium silicate.

S4, slowly introducing carbon dioxide gas into the water extract in the step S3 for carbonation decomposition, stopping introducing the carbon dioxide when the pH value of the water extract reaches 6.0, and performing solid-liquid separation to obtain silica gel and Na₂CO₃Filtering, adding Na₂CO₃Concentrating the filtrate, and then applying the concentrated filtrate to S1 as an auxiliary agent for wet batching.

S5, performing dust removal and purification on furnace gas generated in S2 through a dust remover, cooling, fully burning, collecting and dissolving combustion products with water to obtain a sulfuric acid solution, adjusting the concentration of the sulfuric acid solution to 2mol/L, mixing the sulfuric acid solution with water leaching slag generated in S3 according to the solid-liquid mass ratio of 1:15, stirring and leaching at 25 ℃ for 20min, and filtering to obtain filter residue and filtrate A; the filter residue contains metal salt which is insoluble in sulfuric acid solution and other solid residue (insoluble in water and insoluble in dilute sulfuric acid); the filtrate A contains metal salts dissolved in sulfuric acid solution (part of metal hydroxides and dilute sulfuric acid are subjected to acid-base neutralization and are dissolved in the dilute sulfuric acid), including silicates insoluble in alkali liquor and soluble in sulfuric acid (some water-insoluble silicates react with the dilute sulfuric acid to generate silicic acid and soluble sulfates).

The method for adjusting the concentration of the sulfuric acid comprises the following steps: adding concentrated sulfuric acid/evaporating concentration to increase the concentration of the sulfuric acid solution or adding water for dilution to reduce the concentration of the sulfuric acid solution, and finally obtaining the dilute sulfuric acid solution with the concentration of 2-5 mol/L.

S6, heating the filtrate A to 30 ℃, aging for 10h, and carrying out solid-liquid separation to obtain silica gel and filtrate B, wherein the filtrate B is a desiliconized metal salt solution. Heating and aging to separate silicic acid from the filtrate A in the form of silica gel.

S7, combining the silica gel obtained in the steps S4 and S6, mixing the silica gel and water according to the mass ratio of 1:5, pulping, and spray-drying at 200 ℃ to obtain the silicon dioxide micropowder.

And S8, slowly adjusting the pH value of the filtrate B by using a sodium hydroxide solution with the mass concentration of 20%, slowly dripping the sodium hydroxide solution into the filtrate B, measuring the pH value after stirring, standing the filtrate B after the preset pH value is reached, precipitating iron and aluminum in the range of pH value of 1.5-5.2, filtering and centrifuging the iron hydroxide and the aluminum hydroxide to remove the iron hydroxide and the aluminum hydroxide, and continuously dripping the sodium hydroxide solution into the filtrate B to obtain magnesium hydroxide precipitate at the pH value of 9.4-12.4.

The method of the embodiment recovers Si in the tailings of the copper-nickel sulfide ores and prepares the Si micro-powder product, and also recovers Mg in the tailings of the copper-nickel sulfide ores and prepares the Mg hydroxide product. According to the method, high value-added utilization can be carried out on the copper-nickel sulfide ore tailings, and waste is changed into valuable.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.