Patent ID: 7922989

Claim:
A method of producing silicon having high purity suitable for photovoltaic cells, the method comprising (a) obtaining an aqueous alkali metal silicate solution from a silicon containing material; (b) filtering the aqueous alkali metal silicate solution to remove solid impurities, said solid impurities comprising a compound containing phosphorous; (c) treating the aqueous alkali metal silicate solution with a boron specific chelating resin, wherein the boron specific chelating resin is an ion exchange resin having a functional group of N-methylglucamine; (d) converting the aqueous alkali metal silicate solution to purified silica, wherein the purified silica has a low amount of boron and phosphorous suitable for photovoltaic cells; and (e) reducing the purified silica with a carbonaceous agent, wherein steps (b) and (c) are both performed in a basic condition.