Method for producing trichlorosilane by utilizing photovoltaic crystalline silicon processing waste mortar

Abstract

The invention relates to a method for producing trichlorosilane by utilizing photovoltaic crystalline silicon processing waste mortar, which comprises the following steps of: separating the photovoltaic crystalline silicon processing waste mortar according to application number 201110101064.7<novel method of comprehensively treating photovoltaic crystalline silicon processing waste mortar>, and recovering PEG (polyethylene glycol) and iron to obtain binary sand containing Si and SiC; carrying out double replacement reaction to potassium chloride and sulfuric acid to obtain potassium sulfate; freezing, dehydrating and preheating byproduct HCl to obtain qualified HCl gas, using the HCl gas to carry the binary sand to an air stream bed reactor to form rotational flow, and separating and precipitating SiC favorable for reaction and non reaction of Si+3HCl=SiHCl3+H2; using the reaction product to carry the non reaction SiC micropowder to a separation purification system, and separating by a dust collection device to recover the SiC micropowder; and separating and purifying according to different physicochemical properties of Si chloride to obtain high-purity SiHCl3, which is used for preparing photovoltaic crystalline silicon materials and organosilane of series of products of organic silicon and alkyl, aryl and organic functional group chlorosilane and the like.

Description

technical field [0001] The invention relates to a method for producing trichlorosilane by using waste mortar processed from photovoltaic crystal silicon, and belongs to the field of comprehensive utilization of solar photovoltaic crystal silicon processing waste. Background technique [0002] Trichlorosilane is an intermediate for the production of photovoltaic crystalline silicon, and is also a raw material for the synthesis of organosilanes, alkyl groups, aryl groups, and organofunctional chlorosilanes. The main preparation methods are: (1) Si and HCl reaction; (2) Hydrogen reduction of tetrachlorosilane Silicon oxide (using catalysts containing aluminum compounds). The method (1) is the most widely used, and the reaction raw material Si powder adopts metallurgical grade silicon powder: Si≥98.5%, Fe≤0.5%, Al≤0.5%, Ca≤0.3%, P 2 o 5 ≤0.3%, particle size 80-200 mesh (75-180um); HCl uses H from electrolyzed saline 2 ↑ and Cl 2 ↑Reaction preparation; Si+3HCl↑=SiHCl 3 ↑+H ...

AI Technical Summary

Problems solved by technology

The current treatment technology can only recycle the PEG and SiC micropowder, while the most valuable Si micropowder (crystalline silicon cutting debris) is treated as waste because of the chemical reaction during the treatment process, resulting in serious waste of resources and environmental pollution.

Images