Authors: B. Wasmund and K. Adham
Abstract
A process is disclosed for regenerating an aqueous acid halide leachant from a spent aqueous metal halide leach liquor. The process comprises introducing into a fluidized bed or spray roaster a hydrocarbon fuel, an oxygen-enriched oxidizing gas and the aqueous metal halide leach liquor by combusion of the hydrocarbon fuel with the oxygen-enriched oxidizing gas to produce an acide hailde-containing gas fraction and a metal oxide-containing solid fraction; seperating the gas fraction from the solid fraction, recovering heat energy from the acid balide-containing gas fraction and absorbing the gas fraction in water to produce the aqueous acid halide leachant. The oxygen-enriched oxidizing gas has an oxygen concentration of greater that about 21 percent by volume, preferably greater that about 50 percent by volume, more preferable greater that about 80 percent y bolve, and even more preferably greater than about 90 percent by volume. Preferable, the aqueous metal halide is iron (II) chloride or nickel chloride. Despite higher costs associated witht he oxygen-enriched oxidizing gas as compared to air, the process is capable of being operated more economically and efficiently than equivalent air roasting pyrohydrikysis, and produces a higher concentration aqueous halide leach liquoe, which is preferred in metallurgical processes such as solvent extraction and solids leaching.
