An Environmentally Friendly Route to Silicon Production

R & D UPDATE

Industrial processes for the production of elemental silicon are generally based on the reduction of silicon dioxide (SiO^sub 2^, quartz) by carbon at 1,700�C. In this reaction, carbon reacts with the oxygen in the quartz to form carbon dioxide (CO2). Wuhan Univ. (Wuhan, China; www.lib.whu.edu.cn) chemists have found a way to produce pure Si without the use of carbon as a reductant. The technique involves the electrochemical reduction of SiO^sub 2^. powder in the form of 1.3-cm-dia. pellets to pure Si in molten calcium chloride (CaCl^sub 2^), the electrolyte, at 850�C.

Since SiO^sub 2^ is an insulator, it does not conduct electricity. However, the conversion …