Method for removing silicon from high-silicon acidic solution

Abstract

The invention belongs to the technical field of silicon impurity removal in hydrometallurgy, and particularly relates to a method for removing silicon from a high-silicon acidic solution. The method for desiliconizing from the high-silicon acidic solution comprises the following steps: adding bentonite into the high-silicon acidic solution to carry out desiliconizing treatment; the high-silicon acidic solution is an acid leaching solution generated by silicon-containing minerals or silicon-containing solid wastes in an acid leaching process. Bentonite is adopted as a desiliconizing agent, the bentonite contains a large number of hydroxyl groups and layered structures, destabilization and precipitation are conducted through physical adsorption, surface complexing and electrostatic interaction, the net structure of silica gel is damaged, the viscosity of a system is reduced, the filtering performance of acid leaching liquid is improved, and favorable conditions are created for follow-up metal recovery. The method is especially suitable for a typical high-silicon acidic system in the metallurgical industry, and has great industrial application potential.

Description

Technical Field

[0001] The invention relates to the technical field of silicon impurity removal in hydrometallurgy, and in particular to a method for removing silicon from a high-silicon acidic solution. Background Art

[0002] During the hydrometallurgical smelting of high-silicon minerals such as copper slag, fly ash, and high-silicon zinc ore, acidic leachates with high silicon concentrations are often generated. Silicon in these solutions exists as monomeric silicic acid (H4SiO4) or its polymers, which readily self-aggregate to form silica gel. This colloid, typically with a particle size of 0.001 to 0.1 μm, possesses a strong hydration capacity and can form a continuous three-dimensional network structure within the solution. This significantly increases the viscosity of the system, resulting in reduced filtration performance, difficulties in solid-liquid separation, and even severe constraints on subsequent metal recovery operations.

[0003] The commonly used desiliconization methods include: pH adjustment method, precipitant method, polymer flocculation method, pH adjustment method, and adsorption method. pH adjustment method: by adjusting the pH value to promote the destabilization and precipitation of silicic acid, but this method often requires the addition of a large amount of neutralizer, accompanied by the generation of a large amount of neutralization by-products, which significantly increases the pressure of subsequent treatment and discharge; precipitant method: using Ca 2+ 、Fe 3+ 、Al 3+ Inorganic salts such as silicic acid promote the precipitation of silicic acid, resulting in large precipitated flocs and unstable separation efficiency. Polymer flocculation uses organic polymers to regulate colloidal coagulation, but its effectiveness is significantly affected by acidity and the type of silica. Adsorption methods such as activated alumina, zeolite, or modified clay have a certain adsorption capacity for silicic acid, but are relatively expensive and require long treatment cycles. Therefore, there is an urgent need to develop a new, cost-effective desiliconization method that is suitable for acidic conditions and has good filtration performance improvement. Summary of the Invention

[0004] The object of the present invention is to provide a method for desiliconization from a high-silicon acidic solution, so as to solve the problems of poor filtration performance and poor adaptability to acidic environments in existing desiliconization methods.

[0005] In order to solve the above technical problems, the technical solution of the method for desiliconization from a high-silica acidic solution of the present invention is as follows: A method for desiliconizing from a high-silicon acidic solution comprises the following steps: adding bentonite to the high-silicon acidic solution for desiliconization; the high-silicon acidic solution is an acidic leachate produced in an acid leaching process of silicon-containing minerals or silicon-containing solid wastes.

[0006] This invention improves upon existing technologies by providing a method for desiliconization from highly silicic acidic solutions. The method utilizes bentonite as a desiliconizing agent. Bentonite, with its rich layered structure and numerous hydroxyl groups and exchange sites, promotes the destabilization and precipitation of silicic acid species through physical adsorption, surface complexation, and electrostatic interactions, thereby achieving desiliconization. The method exhibits excellent performance in improving filterability, reducing viscosity, and increasing metal recovery, significantly enhancing the destabilization and precipitation efficiency of silicic acid under acidic conditions. Compared to traditional methods, this method is simple to operate, low-cost, and environmentally friendly, making it particularly suitable for desiliconization of highly silicic acidic systems in industry.

[0007] Preferably, the silicon content in the high-silicic acid solution is 4 g / L to 16 g / L, and the pH is <3.

[0008] Preferably, the amount of bentonite added is 30-50% of the silicon content in the high-silicic acid solution. By adjusting the amount of bentonite added, the desiliconization efficiency can be further improved and the utilization rate of the bentonite can be increased.

[0009] Preferably, the desiliconization treatment temperature is 50-90°C, and the desiliconization treatment time is 1-2 hours. Performing the desiliconization treatment under heating conditions can further improve the desiliconization efficiency. More preferably, the desiliconization treatment temperature is 60-70°C.

[0010] Preferably, the desiliconization treatment is carried out under stirring conditions. Stirring can ensure that the desiliconizing agent bentonite and the silicic acid are in full contact, thereby improving the desiliconization efficiency. Moreover, heating and stirring can significantly improve the destabilization and precipitation efficiency of the silicic acid under acidic conditions.

[0011] Preferably, solid-liquid separation is performed after the desiliconization treatment, and the precipitate obtained by the solid-liquid separation is washed and dried.

[0012] Preferably, the silicon-containing mineral includes high-silicon lead-zinc oxide ore, and the silicon content of the high-silicon lead-zinc oxide ore is 8-10%; the silicon-containing solid waste includes fly ash and copper slag, the silicon content of the copper slag is 9-12%, and the silicon content of the fly ash is 20-25%. DETAILED DESCRIPTION

[0013] The technical concept of the method for desiliconization from a high-silica acidic solution provided by the present invention is as follows: Current mainstream desiliconization methods, such as pH adjustment, precipitation, and adsorption, are complex to operate, costly, or difficult to scale up industrially. The present invention utilizes bentonite as a desiliconizing agent. Taking advantage of its large number of hydroxyl groups and layered structure, the desiliconization precipitate is destabilized through physical adsorption, surface complexation, and electrostatic interaction. This destabilizes the silica gel network, reduces the system viscosity, and improves the filtration performance of the acidic leachate, creating favorable conditions for subsequent metal recovery. This method has the advantages of simple operation, mild conditions, inexpensive raw materials, and a wide range of applicability. It is particularly suitable for high-silica acid systems typical of the metallurgical industry and has great potential for industrial application.

[0014] The present invention provides a method for desiliconization from a high-silicon acidic solution, comprising the following steps: adding bentonite to the high-silicon acidic solution, wherein the amount of bentonite added is 50-70% of the silicon content in the high-silicon acidic solution, stirring at 50-90°C for 1-2 hours to perform desiliconization treatment, performing solid-liquid separation after the desiliconization treatment, and washing and drying the precipitate obtained by the solid-liquid separation; the high-silicon acidic solution is an acidic leachate generated in an acid leaching process of silicon-containing minerals or silicon-containing solid wastes, wherein the silicon-containing minerals include high-silicon lead-zinc oxide ore, and the silicon-containing solid wastes include fly ash and copper slag, the silicon content in the high-silicon acidic solution is 4 g / L-16 g / L, and the pH is <3.

[0015] In a specific embodiment, the acidic leaching solution is obtained by reacting silicon-containing minerals or silicon-containing solid waste with acid solution and then adding water for leaching.

[0016] In a specific embodiment, the mass ratio of the silicon-containing mineral or silicon-containing solid waste to the acid solution is (1-2): (2-4), the acid solution is 98% concentrated sulfuric acid; the volume of water leached per 20g of silicon-containing mineral or silicon-containing solid waste is 100-120mL; the reaction temperature is 150-250°C, and the reaction time is 0.5-1h.

[0017] The embodiments of the present invention are further described below with reference to specific examples. Unless otherwise specified, the chemical reagents involved in the following examples are all commercially available conventional products.

[0018] 1. Specific embodiments of the method for desiliconization from a high-silica acidic solution of the present invention Example 1 The method for desiliconization from a high-silicon acidic solution in this embodiment is as follows: 1) High silica acidic solution 20 g of copper slag was slurried with 12 g of water, and 40 g of concentrated H₂SO₄ (98%) was added and stirred rapidly. The mixture was then placed in a muffle furnace and reacted at 250 °C for 0.5 h. The reacted material was removed from the muffle furnace, added with 100 mL of water, and stirred and leached for 1 h to obtain a highly silicate solution. The main chemical components of the copper slag are shown in Table 1.

[0019] Table 1 Main chemical components of copper slag

[0020] 2) Desiliconization treatment Bentonite (CAS: 1302-78-9, Al2O3· 4(SiO2)· H2O, BENTONE 27, Aladdin Biochemical Technology Co., Ltd.) with a silicon content of 50% was added to the high-silicon acidic solution obtained in step 1) (silicon content of 8 g / L, pH = 0) as a desiliconizing agent. The solution was stirred at 60°C for 1 h for desiliconization. The desiliconized high-silicon acidic solution was poured into a Buchner funnel and vacuum filtration was used for solid-liquid separation to obtain a precipitate and a supernatant. The filtration rate was 0.5 m 3 / (m 2 h) Wash and dry the precipitate. This improves filtration performance, reduces the moisture content of the silicon slag, and reduces the amount of metal carried away in the silicon slag, thereby increasing metal ion recovery.

[0021] Example 2 The method for desiliconization from a high-silicon acidic solution in this embodiment is as follows: 1) High silica acidic solution 20 g of fly ash was mixed with 14 g of water, and 40 g of concentrated H₂SO₄ (98%) was added and stirred rapidly. The mixture was then placed in a muffle furnace and reacted at 200 °C for 0.5 h. The reacted material was removed from the muffle furnace, added with 100 mL of water, and stirred and leached for 1 h to obtain a highly silicate solution. The main chemical components of the fly ash are shown in Table 2.

[0022] Table 2 Main chemical components of fly ash element Al Ca Fe K Si Ti Content (wt%) 21.23 0.36 1.82 0.41 22.21 0.86 2) Desiliconization treatment Bentonite with a silicon content of 30% (same as in Example 1) was added to the high-silicon acidic solution obtained in step 1) (silicon content of 8 g / L, pH = 0) as a desiliconizing agent, and the mixture was stirred at 70°C for 1 hour for desiliconization. The high-silicon acidic solution after desiliconization was poured into a Buchner funnel and vacuum filtration was used for solid-liquid separation to obtain a precipitate and a supernatant. The filtration rate was 0.45 m 3 / (m 2 h), washing and drying the precipitate.

[0023] Example 3 The method for desiliconization from a high-silicon acidic solution in this embodiment is as follows: 1) High silica acidic solution 20 g of high-silicon lead-zinc oxide ore was slurried with 14 g of water. 80 g of concentrated H₂SO₄ (98%) was then added and stirred rapidly until uniform. The slurry was then placed in a muffle furnace and reacted at 150 °C for 0.5 h. The reacted material was removed from the muffle furnace, added with 100 mL of water, and stirred and leached for 1 h to obtain a high-silicon acidic solution. The main chemical components of the high-silicon lead-zinc oxide ore are shown in Table 3.

[0024] Table 3 Main chemical components of high-silicon lead-zinc oxide ore element Al Ca Cu Fe K Mg Mn Si Pb Zn Content (wt%) 22.23 2.84 0.049 5.37 0.32 0.87 0.23 8.21 15.82 25.13 2) Desiliconization treatment Bentonite with a silicon content of 40% (same as in Example 1) was added to the high-silicon acidic solution obtained in step 1) (silicon content of 8 g / L, pH = 0) as a desiliconizing agent, and the mixture was stirred at 70°C for 2 h for desiliconization. The desiliconized high-silicon acidic solution was poured into a Buchner funnel and vacuum filtration was used for solid-liquid separation to obtain a precipitate and a supernatant. The filtration rate was 0.7 m 3 / (m 2 h), washing and drying the precipitate.

[0025] High silicic acid solutions are usually viscous or almost unfilterable due to the high content of colloidal silicic acid. After desiliconization treatment with bentonite, the filtration rate of the system was increased to 0.45~0.7 m 3 / (m 2 h), the filter cake has a good structure, indicating that the colloidal silica has been effectively destabilized and precipitated. This significant improvement in filtration rate is a direct engineering reflection of the desiliconization effect.

[0026] 2. Comparative Example Comparative Example 1 The method for desiliconization from the high-silica acidic solution of this comparative example is as follows: 1) High silica acidic solution 20 g of high-silicon lead-zinc oxide ore (the main chemical composition is the same as in Example 3) was slurried with 14 g of water, and 80 g of concentrated H2SO4 (98%) was added and quickly stirred evenly. The mixture was then placed in a muffle furnace and reacted at 150 °C for 0.5 h. The reacted material was taken out of the muffle furnace, 100 mL of water was added, and stirred and leached for 1 h to obtain a high-silicon acidic solution.

[0027] 2) Desiliconization treatment Bentonite with a silicon content of 40% was added to the high-silicon acid solution obtained in step 1) as a desiliconizing agent, and the solution was stirred at 20°C for 2 h for desiliconization. The high-silicon acid solution after desiliconization was poured into a Buchner funnel and vacuum filtration was used for solid-liquid separation to obtain a precipitate and a supernatant. The filtration rate was 0.5 m 3 / (m 2h), washing and drying the precipitate.

[0028] Comparative Example 2 The method for desiliconization from a high-silicon acidic solution in this embodiment is as follows: 1) High silica acidic solution 20 g of high-silicon lead-zinc oxide ore (the main chemical composition is the same as in Example 3) was slurried with 14 g of water, and 80 g of concentrated H2SO4 (98%) was added and quickly stirred evenly. The mixture was then placed in a muffle furnace and reacted at 150 °C for 0.5 h. The reacted material was taken out of the muffle furnace, 100 mL of water was added, and stirred and leached for 1 h to obtain a high-silicon acidic solution.

[0029] 2) Desiliconization treatment Polyacrylamide (cationic type) with a silicon content of 5% was added to the high-silicon acidic solution obtained in step 1) as a desiliconizing agent, and the solution was stirred at 20°C for 2 h for desiliconization. The high-silicon acidic solution after desiliconization was poured into a Buchner funnel and vacuum filtration was used for solid-liquid separation to obtain a precipitate and a supernatant. The filtration rate was 0.4 m 3 / (m 2 h), washing and drying the precipitate.

[0030] In other comparative examples, when stirring was not performed (other steps were the same as those in Example 3), the bentonite could not fully react with the silica gel particles, the filtration performance was very poor, and the filtration effect was not significantly improved.

[0031] Compared with Example 3, desiliconization at room temperature (Comparative Example 1) and desiliconization using polyacrylamide (Comparative Example 2) both significantly reduce the filtration speed. The filtration speed of Comparative Example 1 is reduced by nearly 30%, and the filtration speed of Comparative Example 2 is reduced by 42%. This shows that the desiliconization method provided by the present invention can significantly improve the filtration performance, facilitate solid-liquid separation, and is beneficial to subsequent metal recovery operations.

[0032] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for desiliconization from a high-silica acidic solution, characterized in that: The following steps are involved: Adding bentonite to high silica acid solution for desiliconization; The high-silicon acidic solution is an acidic leachate produced in the acid leaching process of silicon-containing minerals or silicon-containing solid wastes.

2. The method for desiliconization from a high-silica acidic solution according to claim 1, wherein: The silicon content in the high-silicic acid solution is 4 g / L to 16 g / L, and the pH is <3.

3. The method for desiliconization from a high-silica acidic solution according to claim 1 or 2, characterized in that: The amount of bentonite added is 30-50% of the silicon content in the high-silicic acid solution.

4. The method for desiliconization from a high-silica acidic solution according to claim 1, wherein: The temperature of the desiliconization treatment is 50-90° C., and the time of the desiliconization treatment is 1-2 hours.

5. The method for desiliconization from a high-silica acidic solution according to claim 1 or 4, characterized in that: The desiliconization treatment is carried out under stirring conditions.

6. The method for desiliconization from a high-silica acidic solution according to claim 1, wherein: After the desiliconization treatment, solid-liquid separation is performed, and the precipitate obtained by the solid-liquid separation is washed and dried.

7. The method for desiliconization from a high-silica acidic solution according to claim 1, wherein: The silicon-containing minerals include high-silicon lead-zinc oxide ore, and the silicon content of the high-silicon lead-zinc oxide ore is 8-10%; the silicon-containing solid waste includes fly ash and copper slag, and the silicon content of the copper slag is 9-12%, and the silicon content of the fly ash is 20-25%.

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