Metal recovery by reductive roast and leaching - wherein roasting additive is recovered from off gas and recycled

摘要

Metal values are recovered by subjecting the source to a reductive roast in the presence of an additive and scrubbing the off-gas to remove additive which is recycled. The reduced material is cooled and extracted to recover values. The additive may be HCl gas, H2S, SO2 or a combination of halides and S compounds in gaseous form. Reduction is typically conducted at 500-1000 degrees C and the off gas scrubbed at 50-600 degrees C with fresh metal bearing source. Process is partic. applicable to recovery of Ni, from lateritic ore but scraps or slags may also be treated.