Slag slurry recycling method in cold hydrogenation process and recycling system used in slag slurry recycling method

Abstract

The invention discloses a slag slurry recycling method in a cold hydrogenation process and a slag slurry recycling system used in the method. The slag slurry recycling method in the cold hydrogenationprocess comprises the following steps: carrying out solid-liquid separation on slag slurry in the cold hydrogenation process to respectively obtain separated solid and separated liquid, wherein the solid comprises silicon and a catalyst cuprous chloride, and the liquid comprises chlorosilane; heating the separated solid with zircon sand, a carbonaceous reducing agent and chlorine, reacting the zircon sand, the carbonaceous reducing agent and the chlorine under the catalysis of cuprous chloride in the solid to generate zirconium tetrachloride, silicon tetrachloride and carbon monoxide, and reacting silicon in the solid with the chlorine to generate silicon tetrachloride. The slag slurry in the cold hydrogenation process is applied to the zirconium tetrachloride production process, on one hand, chlorosilane, silicon and the catalyst in the slag slurry are completely recycled and reused, the comprehensive utilization rate of the slag slurry is increased, on the other hand, heat supplementing of the zirconium tetrachloride chlorination reaction is achieved, and energy consumption is reduced.

Description

technical field [0001] The invention belongs to the technical field of polysilicon production, and in particular relates to a method for recycling slag in a cold hydrogenation process and a used recycling system. Background technique [0002] Cold hydrogenation technology has become the mainstream process of trichlorosilane production due to its low energy consumption and large production capacity. In the cold hydrogenation reaction process, in order to increase the conversion rate of silicon tetrachloride, a transition metal catalyst such as a copper-based or nickel-based catalyst is also added in the reaction process. During the reaction process, the catalyst and silicon powder are taken out of the reactor along with the chlorosilane. In addition, in the cold hydrogenation reaction, a certain amount of chlorosilane high boilers will inevitably be generated. This kind of high boiling matter enters the cooling system at the back end together with silicon powder and catalyst...

AI Technical Summary

Problems solved by technology

This treatment method not only reduces the recycling rate of chlorosilane, increases the production cost, but also produces a large amount of industrial waste, which causes a lot of environmental protection costs for enterprises.

In the prior art, for the slurry produced by cold hydrogenation, the chlorosilane liquid in the slurry is mainly recovered, and the recycling of silicon powder and catalyst in the slurry is not considered, resulting in a great waste of resources

Images