Method for recovering and recycling chlorosilane slag slurry

Abstract

The invention relates to a method for recovering and recycling chlorosilane slag slurry and belongs to the technical field of chlorosilane recovery and recycling. The method comprises conveying chlorosilane slag slurry into a solid-liquid separation device, carrying out solid-liquid separation to obtain a liquid phase material and chlorosilane slag slurry, feeding the chlorosilane slag slurry intoa washing device, washing the chlorosilane slag slurry through a hydroxyl-containing solvent and/or a stabilizer to obtain a liquid phase material and a solid phase material, and recovering chlorosilane in the liquid phase materials collected through two processes. According to the method for recovering and recycling chlorosilane slag slurry, the materials participating in a reaction are pure, areaction speed, side reactions and a desired product conversion rate can be effectively controlled, the desired product has high purity, the by-products are less and the disposal and environmental costs of the by-products are greatly reduced.

Description

technical field [0001] The invention relates to a waste recovery and reuse process, more specifically, the invention relates to a process for recovery and reuse of chlorosilane slag slurry, which belongs to the technical field of polysilicon production waste recovery and reuse. Background technique [0002] In the production of polysilicon, while trichlorosilane is reduced to form polysilicon, a large amount of silicon tetrachloride is produced as a by-product. Every ton of polysilicon produced will produce nearly 5 tons of silicon tetrachloride. The reaction equation is as follows: [0003] 4SiHCl 3 + 2H 2 → Si + SiCl 4 + 2SiH 2 Cl 2 + 4HCl [0004] Silicon tetrachloride turns into trichlorosilane after cold hydrogenation or hydrochlorination reaction, and then goes back to produce polysilicon. [0005] The cold hydrogenation reaction equation is as follows: [0006] 3SiCl 4 + 2H 2 + Si (silicon powder) → 4SiHCl 3 [0007] The hydrochlorination reaction equ...

AI Technical Summary

Problems solved by technology

[0014] 1. Spiral dry steaming: the direct recovery rate is 50-80%; the maintenance period is 1-2 months; the working environment of the personnel is poor; the operation and maintenance costs are high; the hydrolysis treatment capacity is still 20-50%, and the environmental protection pressure is extremely high

[0015] 2. Centrifugal separation: the decomposition of chlorosilane under high-speed rotation and the defects of sealing technology are obvious; the working environment of personnel is poor; the failure rate of equipment is extremely high

[0016] 3. Separation by filter press: violent explosion occurs under external pressure, and the safety degree is extremely poor; the working environment for personnel is poor; the failure rate of equipment is extremely high

However, in this method, since the hydroxyl-containing solvent is directly added to the chlorosilane slag slurry, the composition of the chlorosilane slag slurry is complex, and the reaction heat is released very quickly. loss, and also increased the amount of organic waste to be treated

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