Refining and Recycling of Silicon: A Review

Abstract

Silicon has a very broad spectrum of usage nowadays and it lies at the heart of much modern technology. It is the most abundant element in the earth’s crust after oxygen. Indeed, it’s use ranges from such bulk commodities as concrete, clays and ceramics, through more chemically modified systems such as soluble silicates, glasses and glazes to the recent industries based on silicone polymers and solid-state electronics devices. The refined technology of ultra pure silicon itself is perhaps the most elegant example of the close relation between chemistry and solid-state physics and has led to numerous developments such as the transistor, printed circuits and microelectronics.

Three major applications have since greatly stimulated the production and purification of silicon, that is, as an alloy in aluminium, silicones and solid-state electronics. Silicon carbide has also found a broad range of applications taking advantage of its hardness and chemical noble character.

Over the past years, the photovoltaic industry has been experiencing a strong economic growth world-wide. This expansion is due to an increasing demand for PV modules which is expected to continue in the coming years. Since the dominant semiconductor material used in photovoltaics is silicon, in this literature review emphasis is put on the recycling and refining of silicon for photovoltaics (PV).