Drying stirrer and treatment system and method for silicon tetrachloride slag slurry in cold hydrogenation technology

Abstract

The invention provides a drying stirrer for silicon tetrachloride slag slurry in a cold hydrogenation technology. The drying stirrer comprises a shell, a stirring shaft and a transmission device. A drying cavity is defined by the shell. The shell is provided with a feeding port and a discharging port. The stirring shaft is horizontally arranged in the drying cavity and comprises a shaft head and a hollow shaft tube, wherein the shaft head and the hollow shaft tube are welded together. The hollow shaft tube is provided with stirring blades. A first helical band and a second helical band are fixed to the hollow shaft tube through supporting rods and are wound around the periphery of the hollow shaft tube. The respective spiral directions, on the left side and the right side of the hollow shaft tube, of the first helical band and the second helical band are opposite, and the spiral directions of the first helical band and the second helical band are opposite. Under rotation of the stirring shaft, the first helical band enables the slurry to move from the two sides to the middle, and the second helical band enables the slurry to move from the middle to the two sides. The drying stirrer enables the slurry to flow circularly, and the slurry is stirred more evenly. The invention further provides a treatment system and method for the silicon tetrachloride slag slurry.

Description

technical field [0001] The invention relates to the technical field of polysilicon production, in particular to a dry stirrer, a treatment system and a treatment method for silicon tetrachloride slag slurry in a cold hydrogenation process. Background technique [0002] Cold hydrogenation is a process system that converts a large amount of by-product silicon tetrachloride (STC) produced by the reaction in the reduction furnace in polysilicon production into trichlorosilane (TCS) as the raw material for polysilicon synthesis; the raw materials of this process system include silicon powder, STC , hydrogen, HCl, etc., the reaction product is a mixture of hydrogen, STC and TCS, metal chloride and unreacted silicon powder, and the reaction equation involved is Si+2H 2 +3SiCl 4 = 4SiHCl 3 ; Si+3HCl=SiHCl 3 +H 2 . The system separates most of the useful materials such as TCS, STC, and hydrogen through the quencher, and the wet slurry (that is, silicon tetrachloride slurry) afte...

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Problems solved by technology

[0003] The existing drying device has the following problems in the process of use: the slurry does not form a circular flow, there will be a blind area during the drying and stirring process, and there is a phenomenon of uneven heating

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