Slurry recovery system and method in electronic-grade polycrystalline silicon production

Abstract

The invention discloses a slurry recovery system and method in electronic-grade polycrystalline silicon production. The slurry recovery system comprises a rotary filter, an overflow tank, a vacuum paddle dryer, a hydrolysis tank, a condenser and a liquid storage tank, wherein slurry is introduced into the inlet of the rotary filter, the outlet of the rotary filter is communicated with the bottom inlet of the overflow tank, the top outlet of the overflow tank is communicated with the inlet of the vacuum paddle dryer, the bottom outlet of the vacuum paddle dryer is communicated with the top of the hydrolysis tank, the upper end outlet of the hydrolysis tank is connected with a waste liquid pool, the top exhaust port of the vacuum paddle dryer is communicated with the condenser, and the liquid outlet of the condenser is communicated with the inlet of the liquid storage tank. According to the invention, the system has the advantages that tail gas can be directly condensed and recovered, a dust remover is prevented from being blocked, long-period operation of the system is ensured, hydrolysis and neutralization are thorough under the action of a hydrolysis tank stirrer, reaction is mild, the conditions of blasting boiling and incomplete reaction are avoided, discharged gas is stable in the hydrolysis process, and zero emission of HCI is ensured through alkali washing.

Description

technical field [0001] The invention relates to the technical field of polysilicon production, in particular to a slurry recovery system and method thereof in the production of electronic-grade polysilicon. Background technique [0002] The slurry produced in the polysilicon production line contains a lot of chlorosilanes. If it is dumped and buried without proper treatment, it will seriously damage the ecological environment. The slurry mainly comes from the hydrogenation unit, and its main components are silicon powder, silicon tetrachloride, silicon trichloride, high boilers and metal chlorides, of which the content of silicon powder accounts for 20%, the content of chlorosilane accounts for 79.5%, and other It accounts for 0.5%. At present, the domestic treatment process for solid-liquid separation of slurry generally adopts dry vaporization and thickening. A large amount of lye has a relatively high production cost. Therefore, it is an urgent problem for the industry t...

AI Technical Summary

Problems solved by technology

At present, the treatment process of solid-liquid separation of slurry generally adopts dry vaporization and thickening, and the treatment form of the filter residue obtained after thickening is very simple, the process is too simple, the treatment effect is poor, the waste phenomenon is serious, and a large amount of lye is also consumed , the production cost is relatively high

Images