METHOD OF RECOVERING RARE EARTH, ALUMINUM AND SILICON FROM RARE EARTH-CONTAINING ALUMINUM-SILICON SCRAPS

摘要

Disclosed is a method of recovering a rare earth, aluminum and silicon from rare earth-containing aluminum-silicon scraps. The method comprises: S1, performing an acid leaching on the rare earth-containing aluminum-silicon scraps using an aqueous inorganic acid solution to obtain a silicon-rich slag and an acid leached solution containing a rare earth and aluminum element; S2, adding alkali into the acid leached solution containing the rare earth and aluminum element and controlling a pH value of the acid leached solution to a value from 3.5 to 5.2, performing a solid-liquid separation to obtain a deposit containing an aluminum hydroxide and a filter solution containing the rare earth; S3, reacting the deposit containing the aluminum hydroxide with a sodium hydroxide to obtain a sodium meta-aluminate solution and an aluminum-silicon slag, and preparing a rare earth compound product using a filter solution containing the rare earth. The method dissolves an aluminum and rare earth with acid and then via segmented alkaline transfer, deposits aluminum ions to obtain an aluminum hydroxide separate from rare earth ions, and then adds excessive amounts of sodium hydroxide to convert the aluminum hydroxide to a sodium meta-aluminate solution, thereby realizing high-efficiency recovery of both rare earth and aluminum while significantly reducing the consumption of sodium hydroxide and thus recovery cost.