Patent ID: 8337795
Filing Date: 2012-12-25
Classification: C01B,C01P

Abstract:
1. A process for the production of silicon from a material rich in silica comprising the steps of: a) subjecting the material rich in silica to roasting at a temperature of not more than 850° C. for a first period of time, said temperature and first period of time being selected so that silica so obtained is amorphous; b) subjecting the amorphous silica obtained in step a) to a purification step in which the amorphous silica is leached with a lixiviant of aqueous mineral acid; and c) subjecting the leached amorphous silica obtained in step b) to a second roasting at a temperature of less than 750° C. for a second period of time; followed by a step in which the amorphous silica obtained from step c) is subjected to metallothermic or carbothermic reduction to form crystalline silicon.