Metallutvasking og gjenvinningsprosess

摘要

Pt group metals are recovered from an ore concentrate also contg. S by; i) roasting in an O2-contg. atmos. at sufficient temp. to oxidise some of the s, until the S content falls to approx. 2 wt.%, ii) mixing the roasted concentrate with aw. HCl and sufficient HNO3 to enhance dissolution of the metals, and iii) heating the mixt. to sufficient temp. to dissolve a substantial proportion of the metals present. The presence of a sufficient partial pressure of O2 facilitates at least partial regeneration of HNO3.