Method and device for treating residue slurry resulting from trichlorosilane production

Abstract

The invention discloses a method and device for treating residue slurry resulting from trichlorosilane production. The method comprises the following steps: filtering the residue slurry resulting from trichlorosilane production, so as to obtain concentrated residue slurry, wherein a liquid matter obtained through filtering is liquid chlorosilane; and subjecting the concentrated residue slurry to atomizing treatment and carrying out refiltering so as to obtain a gaseous matter, and condensing the gaseous matter so as to obtain liquid chlorosilane, wherein a solid matter obtained through refiltering is filter residue. According to the method and the device, the liquid chlorosilane obtained after residue slurry treatment is free of aluminum chloride, so that the wasting of alkali liquor and chlorosilane and secondary pollution caused by using the alkali liquor in a treatment process are avoided, and the potential safety hazard in the prior art that combustible and explosive gases are generated by hydrolysis during the treatment of the residue slurry resulting from trichlorosilane production is avoided; and the treatment method disclosed by the invention is simple, the recovery ratio of chlorosilane reaches 98% or above, a polycrystalline silicon production process is better completed, the energy saving and consumption lowering effects are considerable, and the treatment cost is reduced greatly.

Description

technical field [0001] The invention belongs to the technical field of polysilicon production, and in particular relates to a method and device for treating slag obtained from trichlorosilane production. Background technique [0002] The polysilicon production system all involves the production process of trichlorosilane, that is, direct chlorination to produce trichlorosilane (reaction of silicon powder and hydrogen chloride) and hydrochlorination to produce trichlorosilane (reaction of silicon tetrachloride, hydrogen and silicon powder). The two kinds of trichlorosilane production processes will eventually obtain slag slurry, which is rich in metal chlorides, a large amount of chlorosilane and solid matter, and the remaining slag slurry contains a large amount of chlorosilane in the slurry. Neutralizing it with liquid will not only cause great waste, but also pollute the environment, and also cause great waste, which involves the treatment process of slag rich in metal chl...

AI Technical Summary

Problems solved by technology

There are two problems in the processing method of the slag slurry obtained from the production of trichlorosilane in the prior art: one, the slag slurry contains a large amount of aluminum chloride, and the temperature in the high-temperature evaporation process of the slag slurry is higher than the sublimation temperature of aluminum chloride , resulting in the sublimation of aluminum chloride, which is mixed into the vaporized chlorosilane, and the vaporized chlorosilane will enter the subsequent separation system after condensation, such as a rectification tower. At this time, the chloride mixed in the vaporized chlorosilane Aluminum will be deposited on the inner wall of the rectification tower, which will affect the mass transfer, heat transfer and tray efficiency of the rectification tower. Of course, it will not only harm the rectification tower, but also affect many devices in the subsequent separation system, such as detectors Contacts, blocking sampling points, destroying shielded pump bearings, etc., and causing corrosion to the inner wall of the equipment in the subsequent process, this insignificant destructive effect will slowly move forward in the entire process system, and ultimately affect product quality

2. Neutralize the thick slag slurry with lye. This hydrolysis process will produce flammable and explosive gases. This process not only uses a large amount of lye, but also regenerates a large amount of filtrate after neutralization. The filtrate belongs to waste water. It needs to be dealt with. Not only is the use of lye itself a waste in this process, but there is still a large amount of chlorosilane in the thick slag. Using lye to neutralize a large amount of chlorosilane in the thick slag will cause a huge loss of chlorosilane at the same time. waste, and increase the complexity of subsequent processing procedures

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