Foam flotation method for separating silicon powder from silicon carbide powder

Abstract

The invention discloses a foam flotation method for separating silicon powder from silicon carbide powder. The foam flotation method includes the steps: 1) using powder generated in cutting of a solar cell as raw materials and obtaining raw materials after acid treatment; 2) adding water into collecting agents, foaming agents and the raw materials after acid treatment to prepare water solution, filling the water solution into a flotation tank for flotation, collecting spilling foam and reserving solid-liquid mixture in the flotation tank; 3) performing flotation again after the foam collected in the step 2 naturally disappears and changes into liquid, and drying the finally obtained foam after suction filtration to obtain silicon; and 4) performing flotation for the solid-liquid mixture reserved in the flotation tank in the step 2 again, and filtering and then drying the solid-liquid mixture finally reserved in the flotation tank to obtain silicon carbide.

Description

technical field [0001] The invention relates to a technology for foam flotation separation of silicon and silicon carbide in powder produced by cutting solar cells. Background technique [0002] Solar cells are generally produced by cutting steel wire saws with silicon carbide abrasive slurry. The diameter of the wire saw is generally 0.18mm, and the width of the saw kerf is generally 0.20-0.30mm, while the thickness of the current solar cell silicon wafer is 0.18-0.22mm. , which means that more than 50% of the silicon material becomes sawdust and enters the slurry during the wire cutting process of silicon wafers. At present, there is a development trend of further thinning the wire saw, but no matter how it develops, about 50% of the silicon material in the photovoltaic industry becomes sawdust and enters the slurry. Therefore, extraction and recovery is equal to opening up a new source of high-purity silicon raw material with considerable scale. [0003] In order to redu...

AI Technical Summary

Problems solved by technology

In the fourth step, the silicon powder will be dissolved by acid washing to obtain a fluorosilicic acid solution, and high-purity silicon cannot be obtained.

Reagents such as tribromomethane required for liquid gravity flotation in this process are very expensive and toxic

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