Device and method for continuous recovery treatment of chlorosilane residual liquid

Abstract

The invention relates to a device and a method for continuous recovery treatment of chlorosilane residual liquid, and particularly relates to a method and a device for recovering hexachlonxlisilane with extremely high value. According to the method, a filter, a primary tower, a hexachlonxlisilane light-component removal column, a hexachlonxlisilane heavy-component removal column, a silicon tetrachloride light-component removal column and a silicon tetrachloride heavy-component removal column are mainly included. The device and the method are especially applicable to treatment of dirt residual liquids such as cold hydrogenation slurry, distillation residues and distillation residues of synthesis procedures during production of polycrystalline silicon as well as treatment of residual liquids such as distillation residues of reduction procedures, distillation residues of thermal hydrogenation procedures or the mixture of both; and based on the device and the method, organic chlorosilane difficultly separating from silicon tetrachloride and titanium tetrachloride difficultly separating from hexachlonxlisilane can be removed, and hexachlonxlisilane with the purity of 99.7 percent can be recovered according to the method.

Description

technical field [0001] The invention relates to a continuous chlorosilane raffinate recovery treatment device and method; in particular, it relates to a recovery method and a device for the recovery of high-boiler hexachlorodisilane (also known as hexachlorodisilane, perchlorodisilane) in chlorosilane. Background technique [0002] Polysilicon is the main raw material required by the electronics industry and the photovoltaic industry, and is a strategic material necessary for the development of my country's electronic information industry and solar photovoltaic industry. [0003] In the production process of polysilicon, a certain amount of raffinate will inevitably be produced along with the tail gas of rectification and purification of chlorosilane synthesis reaction, reduction reaction and cold (hot) hydrogenation reaction. This part of raffinate is useless for the production of polysilicon. In addition, due to the high solid content in this part of the raffinate, which c...

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Problems solved by technology

[0008] Obviously, compared with the reasonable recovery of various components in the raffinate, the hydrolysis of the raffinate will cause huge waste, especially with the continuous expansion of polysilicon production, the raffinate that has not been reasonably recovered will increase exponentially. If the raffinate can be effectively recovered The high value-added components in the liquid, especially hexachlorodisilane, will surely enable enterprises to remain invincible in today's fierce polysilicon market competition

However, due to the many impurities in the chlorosilane raffinate in the cold hydrogenation process and synthesis process, organochlorosilanes such as trichloromethylsilane (boiling point 70.2°C) and silicon tetrachloride (boiling point 56.8°C), titanium tetrachloride (boiling point 136°C) is close to hexachlorodisilane (boiling point 145°C), which requires high recovery, purification and separation process

[0009] U.S. Patent US6090360 proposes to use a continuous spray-drying-based process to recover solids, high boilers, and silicon tetrachloride components in the chlorosilane raffinate, but the actual operation is difficult

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