Chapter 34 - Extraction of Platinum-Group Metals from Russian Ores

Abstract

Russia is the largest primary producer of palladium. Almost all the production comes from mines in the Norilsk-Talnakh region of north Siberia. Norilsk-Talnakh ores are rich in nickel, copper and platinum-group metals (PGMs). Metal production from these ores is limited by the remoteness and harsh Arctic climate of the region. The Norilsk-Talnakh ores contain about 7% nickel, copper and cobalt. In the Russian ores, palladium is more concentrated. All of the PGMs, except platinum, also occur in solid solution in pentlandite. Most of the Norilsk-Talnakh ore is passed through centrifugal density separators before proceeding to froth flotation. The gold in the gravity concentrate is mainly as metallic gold. The gravity concentrate is combined with the nickel and copper electro refinery residues and sent to a precious metals refinery for refining to pure metal. The flotation is mostly done in mechanical flotation cells. Copper sulfide minerals are floated from nickel sulfide minerals by regrinding. The concentrates all contain PGMs, which means that the anodes contain these elements. The anode slimes are collected from the refining cells. The undissolved solids containing the PGMs and gold are collected as the final concentrate and sent to the Kraznoyarsk precious metals refinery for platinum, palladium, rhodium, ruthenium and iridium production. Recent developments in Norilsk-Talnakh are the oxidative pressure leaching of pyrrhotite concentrates to efficiently recover the contained PGMs at high concentration in the residue.