Process for recovering metallic values and process for recovering metallic and acid values

摘要

A process for recovering metal and acid values from a source material containing metallic fluorides comprises digesting the source material in sulfuric acid to form a slurry, separating a fluoride containing solid phase and a metal containing first liquid phase. The solid phase is subjected to pyrohydrolysis, sulfuric and hydrofluoric acids are recovered, and the first liquid phase is processed to recover the metal values by solvent extraction or ion exchanges. The tantalum values are extracted from the first liquid aqueous phase by a water immiscible organic extractant such as methylisobutyl ketone to form a first liquid organic phase containing tantalum and a second liquid aqueous phase. The tantalum is stripped from the first organic phase using water. The process includes the additional steps of heating the separated solid phase from about ambient temperature to an elevated temperature in the presence of water vapor to evolve sulfuric acid and render the gangue chemically inert. When the source material contains uranium the digestion step reduces the amount of gangue present in the radioactive source. The process can include the additional steps of removing uranium from the second liquid aqueous phase by either an ion exchange resin or by solvent extraction using a water immiscible organic extractant to yield a uranium depleted aqueous phase which can be treated with an aqueous solution of calcium oxide. Sulfuric acid and the organic extractant for extracting uranium can be recycled if desired.