Method for reclaiming silicon and silicon carbide from cutting waste materials of monocrystalline silicon and polycrystalline silicon

Abstract

The invention relates to a method for reclaiming silicon and silicon carbide from cutting waste materials of monocrystalline silicon and polycrystalline silicon. The method comprises the following steps of: mixing and stirring hydrochloric acid and dried cutting powder and filtering the mixture through water washing; placing an upper layer solvent and a lower layer solvent into a separation column; adding the preprocessed micropowder into the separation column from the upper part of the separation column, standing for settling, releasing a mixture of the upper solvent and the silicon, releasing a mixture of the lower layer solvent and the silicon carbide, reclaiming the silicon and the silicon carbide respectively by a filtering method through water washing, and reclaiming the solvents; and filtering the reclaimed silicon powder and the silicon carbide powder through water washing and drying the silicon powder and the silicon carbide powder respectively. The method has the advantages that: the purity of the silicon in the refined powder can reach 93 percent and the purity of the reclaimed silicon carbide can reach 86 percent through extraction separation and enrichment; impurity elements harmful to the properties of the high-purity silicon are not introduced; and the process is simple and practicable and equipment is mature.

Description

technical field [0001] The invention belongs to the technical field of silicon materials, and in particular relates to solar-grade polysilicon technology. Background technique [0002] After humans entered the 21st century, with the rapid development of the semiconductor industry, high-purity crystalline silicon materials have been widely used. Among them, crystalline silicon is first pulled into single crystal silicon rods, and then cut into silicon wafers for manufacturing chips. In addition, in recent years, with the increasing shortage of global oil, coal and other energy sources, solar energy has become the most important new energy source in this century due to its unique advantages such as inexhaustible, inexhaustible, clean and environmentally friendly, safe and reliable, and the global solar energy industry Entered a period of rapid development. But at present, the cost of solar power generation is still high, because the polysilicon used to make solar cells is ver...

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Problems solved by technology

[0005] It can be seen from the current recycling situation that the comprehensive recycling of cutting waste has reached a mature stage. Some enterprises in Henan have also manufactured equipment for recycling cutting waste, and the recovery of cutting fluid, silicon carbide and polyethylene glycol has reached a relatively ideal level. effect, and industrialized treatment can be achieved, but the recovery of high-purity silicon is not ideal, because some physical properties of silicon and silicon carbide are similar, and separation is difficult

The most valuable component in cutting waste is silicon, which has a relatively high content. In order to effectively recycle and improve the utilization rate of resources, Dalian University of Technology, Northeastern University, National Taiwan University, etc. and some foreign researchers have carried out research and exploration. , trying to recycle the high-purity silicon in the cutting waste, the research has achieved certain results, but there is no industrialization report

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