Re-use Of Silicon Cutting Fluid

Nowadays, with the high-speed development of photovoltaic industry and communication industry, the demand quantities of monocrystalline silicon increased quickly because of a lot of silicon materials were used. In the whole technics, about 50% monocrystalline silicon becomes silicon wastes. How to recycle these silicon wastes which generated in silicon wafer production process is an important project for insisting on "energy saving, emission reduction, energy, increased efficiency". The raw materials in this paper come from monocrystalline silicon slicing process. This paper gives some suggestions on reuse silicon wastes which are mentioned before, and mainly analyzes silicon waste recycling programs from the following aspects:Firstly, monocrystalline silicon wastes were analyzed to confirm the recycling possibility, and chemical method was used as basic refine step to removing these impurities in silicon wastes. The whole washing project was adjusted according to the analysis result of washed silicon wastes until the final washing project have been determined. The content of silicon in washed silicon wastes can be achieved above 99%, and the main impurity's content decreased very significantly.Then it is found that preparing polycrystalline silicon used in solar cells is very hard in this condition after smelting these washed samples. So this project should find another way to continue this research. Finally, carbon thermal reduction method was successfully used to preparing nano silicon carbide whisker at 1550℃and in the protection of argon. The diameter of nano SiC whisker is about 30nm, and the length is more than 1 micron, to a few microns. Because of its length-diameter ratio is very large, these nano SiC whiskers have a greater value. According to analysis results of nano SiC, the formation mechanism of nano SiC whiskers was discussed and provided a degree of theoretical guidance for future study.To sum up, this paper achieved the purpose of environment protection, decreasing industry wastes and turning wastes into treasure by recycling monocrystalline silicon wastes and preparing nano SiC whiskers successfully in a simple condition. Prepared nano silicon carbide whiskers have excellent physical and chemical properties, so it is hopeful to be widely used in national defense, environmental protection, energy, aviation and transport fields, with high value commercial applications.