Abstract: A method for recovering precious metals such as gold and silver from precious metal-bearing materials that include other solids comprises treating the precious metal-bearing materials with an aqueous, basic solution having a pH in the range of about 12 to about 14 for a time sufficient to suspend the precious metals in substantially free form in the solution, followed by recovery of precious metals from solids and from the solution by known methods.

Abstract: 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.

Abstract: A method for treating water or waste water to remove pollutants therefrom includes treating fly ash comprising aluminum, iron and silica with an aqueous base, recovering a base-treated, solid fly ash, washing the base-treated solid fly ash with water, recovering a rinsed, base-treated fly ash solid, reacting the rinsed, base-treated fly ash solid with mineral acid, and recovering an aqueous, solubilized acidic fly ash leachate, then mixing the aqueous, acidic solubilized fly ash leachate with water or waste water to remove pollutants therefrom, or with sludge to reduce its resistant to dewatering.

Abstract: Methods for making mixtures of hydrocarbons including at least about 85% methane include hydrolyzing at least one metal pseudo-carbide that includes at least one metastable carbide-forming metal element and at least one stable carbide-forming metal element to release methane and the metals, then reforming the pseudo-carbides by reacting the recovered metals with a carbon source such as coal.

Abstract: A process for recovering mineral values from fly ash in commercial quantities comprising forming an alkaline aqueous fly ash blend, filtering the alkaline aqueous fly ash blend and recovering a solids blend therefrom, leaching the solids blend with hydrochloric or hydrofluoric acid to form dissolved chloride or fluoride salts of iron, aluminum and other metals, electrolyzing the dissolved chloride or fluoride salt solution to plate out at least iron, and, optionally, one or more other metals, recovering silicon dioxide as a precipitate from the leaching solution, and recovering the leaching solution free of silicon dioxide. Neutralizing the leaching solution in a certain pH range permits precipitation and recovery of aluminum hydroxide as a solid. The hydroxide may then be converted to alum or alumina by conventional methods.