THE USE OF HYDROGEN TO RECOVER PRECIOUS METALS

ABSTRACT The ability of hydrogen to reduce precious metal ions to their metallic form is well known. Recovery of Pt, Rh and Pd from solutions by H 2 have been studied. The effects of temperature, pressure, gas composition and acid identity and strength have been determined for simple PM solutions. More complex solutions consisting of the PM species and additives such as ammonia, cyanide, acetate and nitrate have also been studied in an effort to evaluate parameters for model solutions. Kinetic data will be used to propose a mechanism for the reduction.