阅读说明：本技术 多晶硅生产中的固渣废弃物回收再利用的方法及装置 (Method and device for recycling solid slag waste in polycrystalline silicon production ) 是由 张凯兴 万宁宁 李珑 杨少军 齐元红 王正坤 刘新岗 马小龙 陈朝霞 于 2018-07-19 设计创作，主要内容包括：本发明公开了一种多晶硅生产中的固渣废弃物回收再利用的方法及装置,该方法包括以下步骤：1)将多晶硅生产中的固渣废弃物与氢氧化钠水溶液混合,多晶硅生产中的固渣废弃物包括硅酸钠和二氧化硅,二氧化硅与氢氧化钠反应生成硅酸钠,得到水玻璃产品。本发明中的多晶硅生产中的固渣废弃物回收再利用的方法及装置,将固渣废弃物转化为可利用资源,实现此类固废“无害化、减量化、资源化”目标,将固渣废弃物作为原料来制备水玻璃产品,使得固渣废弃物充分利用,有效解决了资源浪费问题,并减少环保压力,有效防止了固渣废弃物污染环境。(The invention discloses a method and a device for recycling solid slag wastes in polycrystalline silicon production, wherein the method comprises the following steps of 1) mixing the solid slag wastes in the polycrystalline silicon production with a sodium hydroxide aqueous solution, wherein the solid slag wastes in the polycrystalline silicon production comprise sodium silicate and silicon dioxide, and the silicon dioxide and the sodium hydroxide react to generate the sodium silicate to obtain a water glass product.)

1, solid slag waste recycling method in polysilicon production, which is characterized by comprising the following steps:

1) mixing solid slag waste in the production of the polycrystalline silicon with a sodium hydroxide aqueous solution, wherein the solid slag waste in the production of the polycrystalline silicon comprises sodium silicate and silicon dioxide, and the silicon dioxide reacts with the sodium hydroxide to generate the sodium silicate, so as to obtain the water glass product.

2. The method for recycling solid slag waste in the production of polycrystalline silicon according to claim 1, wherein the initial reaction temperature of the silicon dioxide and the sodium hydroxide in the step 1) is-15 to 45 ℃.

3. The method for recycling the solid slag waste in the polysilicon production according to claim 1 or 2, wherein the solid slag waste in the polysilicon production in the step 1) is mixed with a sodium hydroxide aqueous solution in a closed reaction vessel, the pressure in the closed reaction vessel is increased to 0.1-0.25 MPa along with the reaction by virtue of reaction heat release, the temperature is increased to 80-105 ℃, and the reaction is carried out for 1-3 hours.

4. The method for recycling solid slag waste in the production of polycrystalline silicon according to claim 3, wherein the mixture of the solid slag waste in the production of polycrystalline silicon and the aqueous solution of sodium hydroxide in the step 1) accounts for -two thirds of the volume of the closed reaction vessel.

5. The method for recycling the solid slag waste in the polysilicon production according to claim 3, wherein the step 1) is followed by a step 2) of introducing the water glass product in the closed reaction vessel into a buffer tank connected with the closed reaction vessel for buffering pressure.

6. The method for recycling the solid slag waste in the production of the polycrystalline silicon, according to claim 5, is characterized in that the step 2) is followed by a step 3) of drying the water glass product to obtain a dried water glass product.

7. The method for recycling solid slag waste in the production of polycrystalline silicon according to claim 5 or 6, characterized by further comprising a step m) of introducing the water glass product in the buffer tank into a regulating tank after the step 2), wherein the regulating tank is connected with the buffer tank and is used for observing whether the water glass product contains solids, if the water glass product contains solids, the regulating tank is used for adding a sodium hydroxide aqueous solution into the water glass product in the regulating tank, and the solids in the water glass product react with the sodium hydroxide aqueous solution to generate sodium silicate.

8. The method for recycling the solid slag waste in the production of polycrystalline silicon according to any one of claims 1, 2 and 4 to 6 to , wherein the concentration of the sodium hydroxide aqueous solution in the step 1) is 32 to 55 percent by mass.

9. The method for recycling the solid slag waste in the production of polycrystalline silicon according to any one of claims 1, 2 and 4 to 6 to , wherein the water content in the solid slag waste in the production of polycrystalline silicon in the step 1) is less than 50 mas%.

10. The method for recycling the solid slag waste in the production of polycrystalline silicon according to any one of claims 1, 2 and 4 to 6 to , wherein the mass ratio of the solid slag waste in the production of polycrystalline silicon in the step 1) to the aqueous solution of sodium hydroxide is 1 (0.5 to 1).

11. The method for recycling the solid slag waste in the production of polycrystalline silicon according to any items in claims 1, 2 and 4-6, wherein the solid slag waste in the production of polycrystalline silicon comprises any or more of solid slag waste obtained by leaching tail gas from trichlorosilane synthesis, solid slag waste obtained by leaching tail gas from purification of chlorosilane from trichlorosilane synthesis, and solid slag waste obtained by leaching tail gas from polycrystalline silicon production by chemical vapor deposition.

Technical Field

The invention belongs to the technical field of polycrystalline silicon production, and particularly relates to a method and a device for recycling solid slag waste in kinds of polycrystalline silicon production.

Background

The method is characterized in that hydrogen chloride and industrial silicon powder are used as raw materials to react in a fluidized bed reactor and are controlled within a specific temperature range to react to prepare chlorosilane, the chlorosilane comprises trichlorosilane, silicon tetrachloride, dichlorosilane and the like, the trichlorosilane is purified through a chlorosilane purification process, the refined trichlorosilane is reduced in a reduction furnace to generate polycrystalline silicon, quantitative tail gas is discharged in the normal production and system inspection, maintenance and replacement processes of the trichlorosilane, the tail gas contains hydrogen, hydrogen chloride, nitrogen, chlorosilane gas and the like, the tail gas needs to be treated and then discharged, the tail gas in the traditional polycrystalline silicon production is treated by a tail gas leaching device, namely the hydrogen chloride, the chlorosilane and the like in the tail gas are leached, hydrolyzed, neutralized, the hydrogen and the nitrogen are directly discharged, solid slag (containing sodium silicate and silicon dioxide) generated in the tail gas leaching device is salvaged and stacked, the solid slag stacked causes environmental pollution, and a large amount of solid slag causes environmental pollution, and a large amount of resources are wasted.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art, and provides a method and a device for recycling solid slag waste in polycrystalline silicon production.

The technical scheme adopted for solving the technical problem of the invention is to provide a method for recycling solid slag waste in the production of kinds of polycrystalline silicon, which comprises the following steps:

1) mixing solid slag waste in the production of the polycrystalline silicon with a sodium hydroxide aqueous solution, wherein the solid slag waste in the production of the polycrystalline silicon comprises sodium silicate and silicon dioxide, and the silicon dioxide reacts with the sodium hydroxide to generate the sodium silicate, so as to obtain the water glass product.

Preferably, the initial reaction temperature of the silicon dioxide and the sodium hydroxide in the step 1) is-15 to 45 ℃.

Preferably, the content of silicon dioxide in the solid slag waste is 60-80 mas%.

Preferably, the solid residue waste in the polysilicon production in the step 1) is mixed with the sodium hydroxide aqueous solution in a closed reaction vessel, the pressure in the closed reaction vessel is increased to 0.1-0.25 MPa along with the reaction by virtue of reaction heat release, the temperature is increased to 80-105 ℃, and the reaction is carried out for 1-3 hours. The solid slag waste in the production of the polycrystalline silicon also comprises metal chloride impurities and non-metal chloride impurities, and the content of the impurities is within 6mas percent, such as: PCl₃、BCl₃、AlCl₃、CaCl₂、FeCl₃Impurities. The reaction of the silicon dioxide and the sodium hydroxide to generate the sodium silicate is an exothermic reaction, a large amount of heat is released in the reaction process, the pressure in the closed reaction container is gradually increased, and the rapid reaction is facilitated. In the invention, the solid residue waste in the step 1) of polycrystalline silicon production is mixed with the sodium hydroxide aqueous solution, and can be automatically reacted in a closed reaction container without heating. The impurities in the solid residue waste react with water and release heat to promote the reaction of the silicon dioxide and the sodium hydroxide. A large amount of heat is generated due to the exothermic reaction toAnd the reaction is carried out in the closed container, so that the environment pollution caused by water vapor carrying impurities can be prevented, the pressure in the closed container can be increased, and the reaction can be rapidly carried out.

Preferably, the mixture of the solid slag waste and the sodium hydroxide aqueous solution in the polysilicon production in the step 1) accounts for -two thirds of the volume of the closed reaction vessel.

Preferably, the step 1) is followed by a step 2) of introducing the water glass product in the closed reaction container into a buffer tank connected with the closed reaction container to buffer pressure.

Preferably, step 3) is further included after the step 2) to dry the water glass product, so as to obtain a dry water glass product.

Preferably, step 2) is followed by step m) of introducing the water glass product in the buffer tank into a regulating tank, wherein the regulating tank is connected with the buffer tank and is used for observing whether the water glass product contains solids, if the water glass product contains solids, the regulating tank is used for adding a sodium hydroxide aqueous solution into the water glass product, and the solids in the water glass product react with the sodium hydroxide aqueous solution to generate sodium silicate.

Preferably, the mass percentage concentration of the sodium hydroxide aqueous solution in the step 1) is 32-55%.

Preferably, the water content in the solid slag waste in the step 1) is less than 50 mas%.

Preferably, the mass ratio of the solid slag waste to the sodium hydroxide aqueous solution in the polycrystalline silicon production in the step 1) is 1 (0.5-1).

Preferably, the solid residue waste in the production of the polycrystalline silicon comprises any or more of solid residue waste obtained by leaching tail gas from trichlorosilane synthesis, solid residue waste obtained by leaching tail gas from purification of chlorosilane from trichlorosilane synthesis, and solid residue waste obtained by leaching tail gas from polycrystalline silicon production by chemical vapor deposition.

The invention also provides devices for the method for recycling the solid slag waste in the production of the polycrystalline silicon, which comprise:

the method comprises the following steps of (1) sealing a reaction container, mixing solid slag waste in the production of polycrystalline silicon with a sodium hydroxide aqueous solution in the reaction container, wherein the solid slag waste in the production of polycrystalline silicon comprises sodium silicate and silicon dioxide, and reacting the silicon dioxide with the sodium hydroxide to generate sodium silicate to obtain a water glass product;

the buffer tank is connected with the closed reaction container, the water glass product flows into the buffer tank, and the buffer tank is used for buffering pressure;

and the airing groove is connected with the buffer tank, the water glass product flows into the airing groove, and the airing groove is used for airing and drying the water glass product to obtain a dried water glass product.

Preferably, the apparatus further comprises:

the adjusting tank is arranged between the buffer tank and the airing tank, the adjusting tank is respectively connected with the buffer tank and the airing tank, the water glass product flows into the adjusting tank, the adjusting tank is used for observing whether a solid exists in the water glass product, if the solid exists in the water glass product, the adjusting tank is used for adding a sodium hydroxide water solution into the water glass product, and the solid in the water glass product reacts with the sodium hydroxide water solution to generate sodium silicate.

Preferably, the apparatus further comprises:

the automatic crusher is connected with the airing groove, the dried water glass product enters the automatic crusher, and the automatic crusher is used for automatically crushing the dried water glass product;

and the packaging machine is connected with the automatic crusher and is used for packaging the crushed water glass products.

Preferably, the apparatus further comprises:

the outlet of the dryer is connected with the inlet of the closed reaction container, and the dryer is used for drying solid slag waste in the production of polycrystalline silicon;

and an outlet of the alkali liquor storage tank is connected with an inlet of the closed reaction container, and the alkali liquor storage tank is used for storing a sodium hydroxide aqueous solution.

The method and the device for recycling the solid slag waste in the production of the polycrystalline silicon convert the solid slag waste into usable resources, realize the aims of harmlessness, reduction and recycling of the solid waste, and prepare the water glass product by taking the solid slag waste as a raw material, so that the solid slag waste is fully utilized, the problem of resource waste is effectively solved, the environmental protection pressure is reduced, and the pollution to the environment by the solid slag waste is effectively prevented.

Drawings

Fig. 1 is a schematic structural view of an apparatus used in a method for recycling solid slag waste in polycrystalline silicon production according to embodiment 2 of the present invention;

fig. 2 is a schematic structural view of an apparatus used in the method for recycling solid slag waste in the production of polycrystalline silicon in embodiment 4 of the present invention.

In the figure: 1-a dryer; 2-an alkali liquor storage tank; 3-sealing the reaction container; 4-a buffer tank; 5-adjusting the tank; 6-drying in a slot; 7-an automatic crusher; 8-packaging machine; 9-non-sealed reaction vessel.

Detailed Description

In order to make the technical solution of the present invention better understood, the present invention is further described in detail with reference to the accompanying drawings and the detailed description.