METHOD FOR SEPARATING AND RECOVERING SILICA, ALUMINUM AND IRON FROM FLY ASH MINERAL ORES, AND MINE TAILINGS

摘要

METHOD FOR SEPARATING AND RECOVERING SILICA, ALUMINUM AND IRON FROM FLY ASH, MINERAL ORES AND MINE TAILINGS by JAMES J. RUSS and JOHN W. SMITH A method for separating and recovering substantially pure aluminum, iron and silica from fly ash, a by-product of coal combustion, includes reacting the fly ash with aqueous fluosilicic acid and aqueous hydrogen fluoride at temperatures sufficiently high to form aqueous silicon fluoride vapor and fluorides and fluosilicate of aluminum and iron, separating the aluminum and iron fluorides and fluorosilicates from the aqueous silicon fluoride vapor, hydrolizing the silicon fluoride vapor to form silicon dioxide in substantially pure form and hydrogen fluoride, recovering and recycling the hydrogen fluoride for reuse in the process, and separating the aluminum and iron fluorides and fluosilicates from one another, and recovering substantially pure aluminum fluoride, substantially pure iron and other substantially pure metals, by electroplating or otherwise.