A method for zero-discharge resource utilization of polysilicon waste liquid

Abstract

This invention belongs to the field of industrial waste resource utilization technology, and discloses a zero-discharge resource utilization method for polysilicon waste liquid. The method involves adding sodium hydroxide solution to chlorosilane waste liquid and reacting it, then obtaining sodium silicate solution through stepwise extraction with dilute alkali or one-step extraction with concentrated alkali. Furthermore, calcium carbide slag is calcined and slaked to obtain lime slurry. Then, the sodium silicate solution and lime solution are added to a reaction vessel according to a specific ratio and heated for reaction. The resulting mixture is filtered to obtain microporous calcium silicate material. The filtrate can be recycled as an alkaline solution for chlorosilane waste liquid. This invention effectively solves the problems of scarce resource utilization pathways and low utilization efficiency of chlorosilane waste liquid by synergistically utilizing chlorosilane waste liquid and calcium carbide slag solid waste. The resulting microporous calcium silicate material has excellent physicochemical properties. Simultaneously, the process is simple and the conditions are mild, achieving comprehensive utilization of industrial waste liquid and residue while also contributing to energy conservation, emission reduction, and source environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste resource utilization technology, specifically, it relates to the resource conversion and utilization of polysilicon waste liquid and carbide slag industrial solid waste. Background Technology

[0002] The most common processes used in polysilicon production include the modified Siemens process, the silane fluidized bed process, and the physical metallurgical process, with the modified Siemens process currently being the mainstream method for polysilicon production. The modified Siemens process generates large amounts of chlorosilane waste liquid during the trichlorosilane synthesis reaction, reduction furnace reaction, and cold hydrogenation reaction. This chlorosilane waste liquid is highly corrosive and toxic, classifying it as hazardous waste. Its discharge into the environment causes serious pollution and harm to soil, air, and water. Currently, due to the lack of harmless treatment technology for chlorosilane waste liquid, polysilicon production enterprises cannot effectively treat the waste liquid, resulting in difficulties in waste liquid storage, high disposal costs, and serious secondary environmental pollution problems, which severely affect and restrict the sustainable development of the polysilicon industry.

[0003] The main components of chlorosilane wastewater from polysilicon production are SiCl4 and SiHCl3, with trace amounts of silicon powder and Si2Cl6. Currently, due to a lack of effective comprehensive utilization and treatment technologies, the treatment of chlorosilane wastewater remains at the primary pretreatment stage, mainly employing hydrolysis and distillation methods, with hydrolysis being the most prevalent. While hydrolysis achieves some degree of harmless treatment of chlorosilane wastewater, it results in a significant waste of silicon and chlorine, failing to meet the conditions for resource utilization. Distillation achieves some degree of resource utilization of chlorosilane wastewater, but it also causes secondary pollution, failing to achieve harmless treatment.

[0004] Currently, under increasingly tight resource and environmental constraints, coordinating the expansion of polysilicon production capacity with green and low-carbon development, and achieving the resource-based and harmless disposal of chlorosilane wastewater, is crucial to ensuring the sustainable development of the polysilicon industry. Therefore, there is an urgent need to research and propose comprehensive treatment technologies for chlorosilane wastewater.

[0005] Microporous calcium silicate materials, with the chemical formula CaO·mSiO2·nH2O, possess characteristics such as low density, large specific surface area, high porosity, and strong adsorption. They have wide applications in numerous fields including rubber, papermaking, coatings, pharmaceuticals, pesticides, and environmental protection. In particular, calcium silicate materials with microporous structures exhibit unique structures and superior performance, making their application value and development prospects even broader. The raw materials for preparing microporous calcium silicate are mainly calcareous and siliceous raw materials. Siliceous raw materials are mostly bentonite, quartz, amorphous silica, and diatomaceous earth, while calcareous raw materials are mainly calcium oxide, calcium hydroxide, or calcium-containing limestone. Currently, reported methods for preparing microporous silicate materials mainly include hydrothermal methods, microemulsion methods, and sol-gel methods. From the perspective of raw material sources, there are two main approaches to the preparation of microporous calcium silicate. One approach is to use high-purity silicate raw materials such as quartz powder and high-quality limestone and other calcareous raw materials to prepare microporous hydrated calcium silicate powder materials through hydrothermal synthesis. However, this method has high raw material and energy costs and a complex process, which is not conducive to practical industrial production applications. The other approach is to use solid waste such as fly ash as silicate raw materials and prepare calcium silicate powder materials through multiple steps such as pre-desiliconization and hydrothermal synthesis. However, this method is limited by the activity of silicon and metal impurities in the silicon-containing solid waste raw materials, resulting in a low yield of calcium silicate powder materials and poor performance, which limits the practical application effect and scope. In addition, the process generates a large amount of new "three wastes", which is not conducive to environmental protection and green development. Summary of the Invention

[0006] To address the shortcomings of existing technologies and the lack of effective technologies for the harmless treatment and extraction of chlorosilane wastewater from polysilicon production, this invention provides a zero-discharge resource utilization method for polysilicon wastewater. This method uses chlorosilane wastewater and industrial calcium carbide slag from polysilicon production as raw materials. Through chemical synthesis, it extracts and converts all the highly active silicon abundant in the chlorosilane wastewater into high-purity, high-quality microporous calcium silicate material, which can serve as an excellent rubber filler and adsorbent.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] According to one aspect of the present invention, a method for zero-discharge resource utilization of polysilicon waste liquid is provided, comprising the following processes:

[0009] (1) According to the mass ratio of chlorosilane waste liquid to sodium hydroxide of (1~1.2):1, the chlorosilane waste liquid and sodium hydroxide solution are mixed and reacted at 50~90℃ for 1~2h;

[0010] (2) Filter and separate the mixture after the reaction in step (1) to obtain sodium silicate solution and silicon powder residue;

[0011] (3) According to the mass ratio of silicon powder slag to sodium hydroxide of (75-85):100, the silicon powder slag and sodium hydroxide solution are mixed and reacted at 120-160℃ for 1-1.5h to obtain sodium silicate solution;

[0012] (4) The pretreated carbide slag is continuously calcined in sections at a temperature of 600-980℃ for 2-5.5h;

[0013] (5) The carbide slag obtained in step (4) and water are mixed and reacted at 55-80℃ for 1-1.5h in a mass ratio of 1:((4-10) to obtain lime slurry;

[0014] (6) The sodium silicate solution obtained in steps (2) and (3) and the lime slurry obtained in step (5) are mixed and reacted at 90-120°C for 1-1.5 h at a molar ratio of (0.9-1.1):1. The mixture after reaction is filtered and separated to obtain microporous calcium silicate material and sodium hydroxide filtrate, respectively. The microporous calcium silicate material is dried to obtain microporous calcium silicate product, and the sodium hydroxide filtrate can be recycled as the sodium hydroxide solution in steps (1) and (3).

[0015] Steps (1) to (3) and steps (4) to (5) are parallel and have no particular order.

[0016] Furthermore, in step (1), the mass concentration of the sodium hydroxide solution is 8% to 15%.

[0017] Furthermore, in step (1), the stirring speed of the mixing reaction is 150 r / min to 200 r / min.

[0018] Furthermore, in step (3), the mass concentration of the sodium hydroxide solution is 15% to 20%.

[0019] Furthermore, in step (3), the stirring speed of the mixing reaction is 150 r / min to 200 r / min.

[0020] Further, in step (4), the pretreatment refers to acid washing of the carbide slag with oxalic acid.

[0021] Furthermore, in step (4), the segmented continuous calcination is first calcined at 600-750℃ for 1-2.5h, and then calcined at 800-980℃ for 1-3h.

[0022] Furthermore, in step (6), the mass concentration of the lime slurry is 8% to 15%.

[0023] Furthermore, in step (6), the stirring speed of the mixing reaction is 100 r / min to 150 r / min.

[0024] Further, in step (6), the microporous calcium silicate material is dried first at 100-150°C for 1.5-2 hours, and then at 230-300°C for 1-1.5 hours.

[0025] According to one aspect of the present invention, a method for zero-discharge resource utilization of polysilicon waste liquid is provided, comprising the following processes:

[0026] (1) According to the mass ratio of chlorosilane waste liquid to sodium hydroxide (0.9-1):1, the chlorosilane waste liquid and sodium hydroxide solution are mixed and reacted at 150-200℃ for 1.5-2.5h to obtain sodium silicate solution;

[0027] (2) The pretreated carbide slag is continuously calcined in sections at a temperature of 600-980℃ for 2-5.5h;

[0028] (3) The carbide slag obtained in step (2) and water are mixed and reacted at a mass ratio of 1:((4~10) at 55~80℃ for 1~1.5h to obtain lime slurry;

[0029] (4) The sodium silicate solution obtained in step (1) and the lime slurry obtained in step (3) are mixed and reacted at a molar ratio of (0.9-1):1 at 105℃-130℃ for 1.5-2h. The mixture after reaction is filtered and separated to obtain microporous calcium silicate material and sodium hydroxide filtrate, respectively. The microporous calcium silicate material is dried to obtain microporous calcium silicate product, and the sodium hydroxide filtrate can be recycled as the sodium hydroxide solution in step (1).

[0030] Step (1) is parallel to steps (2) to (3) and there is no order in which they are performed.

[0031] Further, in step (1), the mass concentration of the sodium hydroxide solution is 20% to 25%.

[0032] Furthermore, in step (1), the stirring speed of the mixing reaction is 200 r / min to 300 r / min.

[0033] Furthermore, in step (2), the pretreatment refers to acid washing of the carbide slag with oxalic acid.

[0034] Furthermore, in step (2), the segmented continuous calcination is first calcined at 600-750℃ for 1-2.5h, and then calcined at 800-980℃ for 1-3h.

[0035] Furthermore, in step (4), the mass concentration of the lime slurry is 12% to 20%.

[0036] Furthermore, in step (4), the mixing reaction stirring speed is 150 r / min to 200 r / min.

[0037] Further, in step (4), the microporous calcium silicate material is dried first at 90-120°C for 1-2 hours, and then at 200-240°C for 1-1.5 hours.

[0038] The beneficial effects of this invention are:

[0039] (I) This invention opens up a new way for the resource utilization of chlorosilane waste liquid, which can make full use of the useful components in silane waste liquid, realize the complete harmless and resource utilization of chlorosilane waste liquid in polysilicon production, with no "three wastes" production and no secondary pollution, which is conducive to environmental protection and promotes green and low-carbon development.

[0040] (ii) This invention can prepare microporous silicate materials with high purity and good properties, and the products have good performance, wide application and high added value;

[0041] (III) The chlorosilane waste liquid resource utilization process of the present invention is simple, the reaction conditions are mild, the process does not require other raw and auxiliary materials, all reaction solutions are recycled, the process is clean, safe and environmentally friendly, and can be industrialized.

[0042] (iv) This invention also provides a comprehensive utilization method for carbide slag, which broadens the disposal channels for carbide slag and improves the resource utilization value of carbide slag. Attached Figure Description

[0043] Figure 1 The process flow diagrams for the zero-discharge resource utilization method of polysilicon waste liquid in Examples 1-3 of this invention are shown below.

[0044] Figure 2 This is a process flow diagram of the zero-discharge resource utilization method for polysilicon waste liquid in Embodiment 4 of the present invention;

[0045] Figure 3 The process flow diagrams for the zero-discharge resource utilization method of polysilicon waste liquid in Embodiments 5-6 of the present invention are shown below.

[0046] Figure 4 This is a scanning electron microscope image of the microporous silicate material-1 prepared in Example 4 of the present invention;

[0047] Figure 5 This is a scanning electron microscope image of the microporous silicate material prepared in Example 5 of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0049] Example 1

[0050] like Figure 1 As shown:

[0051] Step 1: Take 100.0g of chlorosilane waste liquid and prepare an 8% sodium hydroxide solution according to the mass ratio of chlorosilane waste liquid to sodium hydroxide of 1:1. Add the chlorosilane waste liquid and sodium hydroxide solution to the reaction vessel and stir (stirring rate 150r / min). Control the reaction temperature at 50℃ and react continuously for 1h.

[0052] Step 2: Filter and separate the mixture after the reaction in Step 1 to obtain sodium silicate solution-1 and silica powder residue, respectively.

[0053] Step 3: Take 100.0g of silicon powder residue obtained in Step 2, prepare a 15% sodium hydroxide solution according to the mass ratio of silicon powder residue to sodium hydroxide of 75:100, add the silicon powder residue and sodium hydroxide solution to the reactor and stir (stirring rate 150r / min), control the reaction temperature at 120℃, and react continuously for 1h to obtain sodium silicate solution-2.

[0054] Step 4: Calcining the acid-washed carbide slag at 600℃ for 1 hour, and then calcining it at 800℃ for 1 hour to obtain calcium material.

[0055] Step 5: Take the calcium material obtained in Step 4, add water at a ratio of 1:4, and mix and react at 55℃ for 1 hour to obtain lime slurry.

[0056] Step 6: Add water to the lime slurry obtained in Step 5 to prepare a lime slurry with a mass concentration of 8%. Mix the sodium silicate solution-1 obtained in Step 2 and the sodium silicate solution-2 obtained in Step 3 and add them to the reactor. Add the 8% lime slurry to the reactor according to a silicon-to-calcium molar ratio of 0.9:1 for reaction. Control the reaction temperature at 90℃, react for 1 hour, and maintain the stirring speed of the reactor at 100 r / min. Filter the mixture after the reaction to obtain microporous calcium silicate. Dry the microporous calcium silicate at 100℃ for 1.5 hours, then dry it at 230℃ for 1 hour to obtain microporous calcium silicate material. The sodium hydroxide filtrate after filtering the mixture is returned to Steps 1 and 3 for recycling.

[0057] Example 2

[0058] like Figure 1 As shown:

[0059] Step 1: Take 100.0g of chlorosilane waste liquid and prepare a 15% sodium hydroxide solution according to the mass ratio of chlorosilane waste liquid to sodium hydroxide of 1.2:1. Add the chlorosilane waste liquid and sodium hydroxide solution to the reaction vessel and stir (stirring rate 150r / min). Control the reaction temperature at 90℃ and react continuously for 2h.

[0060] Step 2: Filter and separate the mixture after the reaction in Step 1 to obtain sodium silicate solution-1 and silica powder residue, respectively.

[0061] Step 3: Take 100.0g of the silicon powder residue obtained in Step 2, and prepare a sodium hydroxide solution with a concentration of 18% according to the mass ratio of silicon powder residue to sodium hydroxide of 85:100. Add the silicon powder residue and sodium hydroxide solution to the reactor and stir (stirring speed 150r / min). Control the reaction temperature at 160℃ and react continuously for 1.5h to obtain sodium silicate solution-2.

[0062] Step 4: Calcining the acid-washed carbide slag at 750℃ for 2 hours, and then calcining it at 850℃ for 1 hour to obtain calcium material.

[0063] Step 5: Take the calcium material obtained in Step 4, add water in a ratio of 1:6, mix and react at 55℃ for 1 hour to obtain lime slurry.

[0064] Step 6: Add water to the lime slurry obtained in Step 5 to prepare a lime slurry with a mass concentration of 15%. Mix the sodium silicate solution-1 obtained in Step 2 and the sodium silicate solution-2 obtained in Step 3 and add them to the reactor. Add the 15% lime slurry to the reactor according to a silicon-to-calcium molar ratio of 1.1:1 for reaction. Control the reaction temperature at 120℃, react for 1.5 hours, and maintain the stirring speed of the reactor at 100 r / min. Filter the mixture after reaction to obtain microporous calcium silicate. Dry the microporous calcium silicate at 150℃ for 2 hours, then dry it at 300℃ for 1.5 hours to obtain microporous calcium silicate material. The sodium hydroxide filtrate after filtering the mixture is returned to Steps 1 and 3 for recycling.

[0065] Example 3:

[0066] like Figure 1 As shown:

[0067] Step 1: Take 100.0g of chlorosilane waste liquid and prepare a 12% sodium hydroxide solution according to the mass ratio of chlorosilane waste liquid to sodium hydroxide of 1.1:1. Add the chlorosilane waste liquid and sodium hydroxide solution to the reaction vessel and stir (stirring rate 150r / min). Control the reaction temperature at 80℃ and react continuously for 1.5h.

[0068] Step 2: Filter and separate the mixture after the reaction in Step 1 to obtain sodium silicate solution-1 and silica powder residue, respectively.

[0069] Step 3: Take 100.0g of the silicon powder residue obtained in Step 2, and prepare a 20% sodium hydroxide solution according to the mass ratio of silicon powder residue to sodium hydroxide of 80:100. Add the silicon powder residue and sodium hydroxide solution to the reactor and stir (stirring speed 150r / min). Control the reaction temperature at 140℃ and react continuously for 1.5h to obtain sodium silicate solution-2.

[0070] Step 4: Calcining the acid-washed carbide slag at 600℃ for 1 hour, and then calcining it at 800℃ for 1 hour to obtain calcium material.

[0071] Step 5: Take the calcium material obtained in Step 4, add water at a ratio of 1:8, and mix and react at 55℃ for 1 hour to obtain lime slurry.

[0072] Step 6: Add water to the lime slurry obtained in Step 5 to prepare a lime slurry with a mass concentration of 12%. Mix the sodium silicate solution-1 obtained in Step 2 and the sodium silicate solution-2 obtained in Step 3 and add them to the reactor. Add the 12% lime slurry to the reactor according to a silicon-to-calcium molar ratio of 0.9:1 for reaction. Control the reaction temperature at 110℃, react for 1.5 hours, and maintain the stirring speed of the reactor at 100 r / min. Filter the mixture after reaction to obtain microporous calcium silicate. Dry the microporous calcium silicate at 120℃ for 2 hours, then dry it at 250℃ for 1.5 hours to obtain microporous calcium silicate material. The sodium hydroxide filtrate after filtering the mixture is returned to Steps 1 and 3 for recycling.

[0073] Example 4:

[0074] like Figure 2 As shown:

[0075] Step 1: Take 100.0g of chlorosilane waste liquid and prepare a 12% sodium hydroxide solution according to the mass ratio of chlorosilane waste liquid to sodium hydroxide of 1.1:1. Add the chlorosilane waste liquid and sodium hydroxide solution to the reaction vessel and stir (stirring rate 150r / min). Control the reaction temperature at 80℃ and react continuously for 1.5h.

[0076] Step 2: Filter and separate the mixture after the reaction in Step 1 to obtain sodium silicate solution-1 and silica powder residue, respectively.

[0077] Step 3: Take 100.0g of the silicon powder residue obtained in Step 2, and prepare a 20% sodium hydroxide solution according to the mass ratio of silicon powder residue to sodium hydroxide of 80:100. Add the silicon powder residue and sodium hydroxide solution to the reactor and stir (stirring speed 150r / min). Control the reaction temperature at 140℃ and react continuously for 1.5h to obtain sodium silicate solution-2.

[0078] Step 4: The acid-washed carbide slag is calcined at 600℃ for 2.5 hours, and then calcined at 980℃ for 3 hours to obtain calcium material.

[0079] Step 5: Take the calcium material obtained in Step 4, add water at a ratio of 1:10, and mix and react at 80℃ for 1.5 hours to obtain lime slurry.

[0080] Step 6: Add water to the lime slurry obtained in Step 5 to prepare a lime slurry with a mass concentration of 10%. Add the sodium silicate solution-1 obtained in Step 2 and the 10% lime slurry to the reactor according to a silicon-to-calcium molar ratio of 1:1. Control the reaction temperature at 110℃, react for 1.5 hours, and maintain the stirring speed of the reactor at 100 r / min. Filter the mixture after the reaction to obtain microporous calcium silicate. Dry the microporous calcium silicate at 120℃ for 2 hours, then at 250℃ for 1.5 hours to obtain microporous calcium silicate material-1. The sodium hydroxide filtrate after filtration is returned to Steps 1 and 3 for recycling. Under the same reaction conditions, mix the sodium silicate solution-2 obtained in Step 3 with the lime slurry to obtain microporous calcium silicate material-2.

[0081] Example 5

[0082] like Figure 3 As shown:

[0083] Step 1: Take 100.0g of chlorosilane waste liquid and prepare a 20% sodium hydroxide solution according to the mass ratio of chlorosilane waste liquid to sodium hydroxide of 0.9:1. Add the chlorosilane waste liquid and sodium hydroxide solution to the reaction vessel and stir (stirring rate 200r / min). Control the reaction temperature at 150℃ and react continuously for 1.5h to obtain sodium silicate solution.

[0084] Step 2: The acid-washed carbide slag is calcined at 650℃ for 2 hours, and then calcined at 850℃ for 1.5 hours to obtain calcium material.

[0085] Step 3: Take the calcium material obtained in Step 2, add water at a ratio of 1:6, and mix and react at 60℃ for 1 hour to obtain lime slurry.

[0086] Step 4: Add water to the lime slurry obtained in Step 3 to prepare a lime slurry with a mass concentration of 15%. Add the sodium silicate solution obtained in Step 1 and the 15% lime slurry to the reactor according to a silicon-to-calcium molar ratio of 1:1. Control the reaction temperature at 105℃, react for 1.5 hours, and maintain the stirring speed of the reactor at 150 rpm. After the reaction, filter the mixture to obtain microporous calcium silicate. Dry the microporous calcium silicate at 100℃ for 1.5 hours, then at 200℃ for 1 hour to obtain the microporous calcium silicate material. Return the sodium hydroxide filtrate from the filtered mixture to Step 1 for recycling.

[0087] Example 6

[0088] like Figure 3 As shown:

[0089] Step 1: Take 100.0g of chlorosilane waste liquid and prepare a 25% sodium hydroxide solution with a mass ratio of 1:1 between the chlorosilane waste liquid and sodium hydroxide. Add the chlorosilane waste liquid and sodium hydroxide solution to the reaction vessel and stir (stirring rate 200r / min). Control the reaction temperature at 180℃ and react continuously for 2.5h to obtain sodium silicate solution.

[0090] Step 2: The acid-washed carbide slag is calcined at 750℃ for 1 hour, and then calcined at 800℃ for 3 hours to obtain calcium material.

[0091] Step 3: Take the calcium material obtained in Step 2, add water at a ratio of 1:8, and mix and react at 60℃ for 1 hour to obtain lime slurry.

[0092] Step 4: Add water to the lime slurry obtained in Step 3 to prepare a lime slurry with a mass concentration of 20%. According to a silicon-to-calcium molar ratio of 0.9:1, measure out the sodium silicate solution obtained in Step 1 and the 15% lime slurry, and add them to the reactor for reaction. The reaction temperature is controlled at 120℃, and the reaction time is 2 hours, with the reactor stirring speed at 150 r / min. After the reaction, filter the mixture to obtain microporous calcium silicate. Dry the microporous calcium silicate at 90℃ for 2 hours, then at 240℃ for 1 hour to obtain microporous calcium silicate material. The sodium hydroxide filtrate after filtration of the mixture is returned to Step 1 for recycling.

[0093] In step 4, the silicon-calcium molar ratio is 0.9:1, the lime slurry concentration is 15%, the reaction temperature is 120℃, and the reaction time is 2 hours. The microporous calcium silicate is first dried at 150℃ for 2 hours, and then dried at 250℃ for 1.5 hours to obtain the microporous calcium silicate material.

[0094] The whiteness, bulk density, oil absorption value, specific surface area, and water content of the microporous silicate materials prepared in Examples 1-6 of this invention were measured, and the results are shown in Table 1:

[0095] Table 1 Comparison of physical properties of microporous silicate materials prepared in Examples 1-6

[0096]

[0097]

[0098] As can be seen from Table 1, the microporous silicate materials prepared by the two-step silica extraction method in Examples 1-4 of this invention have good whiteness, specific surface area, oil absorption value, and other properties. In particular, the microporous silicate material-1 prepared in Example 4 has even better performance and is suitable for use as a filler in the production of paper and rubber, with high added value. The microporous silicate materials prepared by the one-step silica extraction method in Examples 5-6 of this invention have well-developed surface pores and a large specific surface area, making them suitable as adsorbent materials for the treatment of waste gas and wastewater pollution, with a wide range of applications.

[0099] Figure 4 and Figure 5 The results show that the microporous calcium silicate material prepared by this invention is composed of a large number of microparticles with a particle size of about 10-30 μm. The microparticles have pores both inside and on the surface. The interior is composed of disordered sheet-like and rolled layered particles, and the surface has a honeycomb structure. It is a loose structural material with high porosity.

[0100] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for zero-discharge resource utilization of polysilicon waste liquid, characterized in that, The process includes the following: (1) According to the mass ratio of chlorosilane waste liquid to sodium hydroxide of (1~1.2):1, the chlorosilane waste liquid and sodium hydroxide solution are mixed and reacted at 50~90℃ for 1~2h; (2) Filter and separate the mixture after the reaction in step (1) to obtain sodium silicate solution and silica powder residue; (3) According to the mass ratio of silicon powder slag to sodium hydroxide of (75~85):100, the silicon powder slag and sodium hydroxide solution are mixed and reacted at 120~160℃ for 1~1.5h to obtain sodium silicate solution; (4) The pretreated carbide slag is continuously calcined in sections at a temperature of 600~980℃ for 2~5.5h; The pretreatment refers to acid washing of the carbide slag with oxalic acid; the segmented continuous calcination is to first calcine at 600~750℃ for 1~2.5h, and then continue calcining at 800~980℃ for 1~3h. (5) Mix the carbide slag obtained in step (4) and water at a mass ratio of 1:((4~10) and react at 55~80℃ for 1~1.5h to obtain lime slurry; (6) The sodium silicate solution obtained in steps (2) and (3) and the lime slurry obtained in step (5) are mixed and reacted at 90-120°C for 1-1.5 h at a molar ratio of (0.9~1.1):

1. The mixture after reaction is filtered and separated to obtain microporous calcium silicate material and sodium hydroxide filtrate, respectively. The microporous calcium silicate material is dried to obtain microporous calcium silicate product, and the sodium hydroxide filtrate can be recycled as the sodium hydroxide solution in steps (1) and (3). Steps (1) to (3) and steps (4) to (5) are parallel and have no particular order.

2. The method for zero-discharge resource utilization of polysilicon waste liquid according to claim 1, characterized in that, In step (1), the mass concentration of the sodium hydroxide solution is 8%~15%.

3. The method for zero-discharge resource utilization of polysilicon waste liquid according to claim 1, characterized in that, In step (3), the mass concentration of the sodium hydroxide solution is 15%~20%.

4. The method for zero-discharge resource utilization of polysilicon waste liquid according to claim 1, characterized in that, In step (6), the mass concentration of the lime emulsion is 8%~15%; the microporous calcium silicate material is dried first at 100~150℃ for 1.5~2h, and then at 230~300℃ for 1~1.5h.

5. A method for zero-discharge resource utilization of polysilicon waste liquid, characterized in that, The process includes the following: (1) According to the mass ratio of chlorosilane waste liquid to sodium hydroxide (0.9 ~ 1): 1, the chlorosilane waste liquid and sodium hydroxide solution are mixed and reacted at 150 ~ 200 °C for 1.5 ~ 2.5 h to obtain sodium silicate solution; (2) The pretreated carbide slag is continuously calcined in sections at a temperature of 600~980℃ for 2~5.5h; The pretreatment refers to acid washing of the carbide slag with oxalic acid; the segmented continuous calcination is to first calcine at 600~750℃ for 1~2.5h, and then continue calcining at 800~980℃ for 1~3h. (3) The carbide slag obtained in step (2) and water are mixed and reacted at 55-80℃ for 1-1.5h in a mass ratio of 1:((4~10) to obtain lime slurry; (4) The sodium silicate solution obtained in step (1) and the lime slurry obtained in step (3) are mixed and reacted at a molar ratio of (0.9~1):1 at 105℃~130℃ for 1.5~2h; the mixture after reaction is filtered and separated to obtain microporous calcium silicate material and sodium hydroxide filtrate, respectively. The microporous calcium silicate material is dried to obtain microporous calcium silicate product, and the sodium hydroxide filtrate can be recycled as the sodium hydroxide solution in step (1). Among them, steps (1) and steps (2) to (3) are parallel and have no particular order.

6. The method for zero-discharge resource utilization of polysilicon waste liquid according to claim 5, characterized in that, In step (1), the mass concentration of the sodium hydroxide solution is 20%~25%.

7. The method for zero-discharge resource utilization of polysilicon waste liquid according to claim 5, characterized in that, In step (4), the mass concentration of the lime slurry is 12%~20%; the microporous calcium silicate material is dried first at 90~120℃ for 1~2h, and then at 200~240℃ for 1~1.5h.

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