Patent ID: 6277349
Filing Date: 2001-08-21
Classification: C01B,C04B

Abstract:
A process for removing at least some of the impurities within the lattice structure of crystalline quartz comprising the steps of:A) heating crystalline quartz with impurities within the lattice structure thereof sufficiently to convert a major portion of the crystalline quartz to the tridymite polymorphic form; and,B) depositing the heated crystalline quartz containing the impurities into an aqueous acid solution whereby the acid in the acid solution reacts with at least some of the impurities within the lattice structure of the quartz to form soluble salts and effectively remove the reacted impurities from the lattice structure of the crystalline quartz while simultaneously evaporating the liquid in the aqueous acid solution and thereby cooling the crystalline quartz to a temperature below the tridymite polymorphic form, the volume of the aqueous acid solution selected such that substantially all of the liquid in said aqueous acid solution is evaporated to obtain a residue containing purified quartz crystals and said soluble salts, and the active amount of acid in said aqueous acid solution selected to react with a sufficient amount of the impurities within the lattice structure of the crystalline quartz to thereby reduce the amount of at least some of the impurities in said crystalline quartz.