Libyan quartz as candidate for solar grade silicon production

Elemental silicon is produced mainly by the Carbo-thermic reduction of silica sand. This technique produces rather impure silicon, which is termed as metallurgical grade silicon. Upgraded metallurgical grade silicon, produced from high purity silica, is usually used to produce semiconductor and solar grade silicon utilized in the manufacturing of microelectronic components of integrated circuits, transistors and solar cells. In this paper, sand from one of the Libyan Desert formations called Ash-Shibat, will be characterized to explore the possibility of its use in the production of high purity silicon. Such sands are thought to be candidate for the production of solar grade silicon. Chemical analysis, x-ray diffraction, and scanning electron microscopy are the main techniques used to characterize the sand and to assess the type and amount of impurities present. The results indicate that impurities such as B, Na, Ca, K, Mg, Al, Ti and Fe are present in the as-received sand in trace amounts. These impurities were found to be contained mainly on the sand particles´ exterior surfaces, and in the binding material between them. The interior of the sand particles are found to be composed mainly of Si and O in the form of quartz silica. It is concluded from this study that further purification and processing of Ash-Shibat sand produce high purity silica that can be used for producing solar grade silicon.