Silicon Production via Reaction of Silicon Tetrachloride and Aluminum Subchloride
- 26 Downloads
Silicon tetrachloride reduction by aluminum subchloride was studied experimentally. Aluminum subchloride was synthesized in a reaction of metallic aluminum and AlCl3; a burner-like construction of the reactor was used to avoid the direct reaction of aluminum and SiCl4. The reduction was conducted at a pressure of 0.1 MPa and two temperature regimes: 1273 K and 1373 K (1000 °C and 1100 °C). As a result, two types of products were obtained: crystals and fine particles. The crystals formation occurred in the high-temperature zone, whereas the particles were dispersed by argon flow and concentrated mainly in aluminum chloride by-product in the cold part of the reactor. It was shown that silicon yield increased with increasing AlCl concentration. The temperature of the reduction process did not have a significant effect on the ultimate silicon yield. However, the silicon etching reaction rate and fine particles yield increased as temperature increased. X-ray diffraction and scanning electron microscopy analysis showed that the impurities content in silicon crystals was below the detection limit. In contrast, the aluminum content in the powder product was 2 to 3 wt pct. Another type of product, yellow blanket-like silicon fibers, was obtained with a high yield at 1373 K (1100 °C) and low [AlCl]:[SiCl4] ratio.
- 4.4. X. Xie, K. Lau and A. Sanjurjo: Metal. Metall. Mater. Trans. E., 2016, vol. 4E, pp. 2017-29.Google Scholar
- 6.J. Myrick: Production of Metals and Their Alloys, WO 01/45906 A2, 2001.Google Scholar
- 13.13. H. Schäffer: Chemical Transport Reactions, Academic press, New York and London, 1964, pp. 40-44.Google Scholar