Recovery of precious metal and other values from spent compositions/materials

摘要

Precious metal values, e.g., platinum, palladium and rhodium, and, optionally, other valuable elements, e.g., one or more rare earths and cerium in particular, are recovered from a wide variety of compositions of matter and articles of manufacture, for example waste or spent catalysts such as vehicular postcombustion catalysts, by (i) optionally comminuting such composition/article into a finely divided state, (ii) intimately admixing the composition/article with sulfuric acid, (iii) calcining the resulting admixture at a temperature ranging from 150 to 450 C., and (iv) leaching the calcined admixture in an aqueous medium, whether simultaneously or separately, with H ^{ions and chloride ions, whereby obtaining (1) a solid residue substantially depleted of such precious metal values and, optionally, of such other elements, and (2) at least one liquid solution comprising such precious metal values and, optionally, such other elements.}