A Summary of U.S. Bureau of Mines Research on Stillwater Complex Platinum-palladium Ore.
Paper in Precious & Rare Metal Tech Elsevier 1989 :395-411
The U.S. Bureau of Mines investigated methods for beneficiating and recovering platinum-group metals from ores from the Stillwater Complex in Montana, the only primary resource of platinum-group metals in the United States. A 100-lb/h flotation pilot plant recovered more than 91 pct of the PGM from the ore. Oxidative leaching of roasted flotation concentrate to selectively extract precious metal values was investigated. Several leaching schemes were developed for selectively extracting the base metals and recovering the PGM from matte prepared by smelting the flotation concentrate. Mining of the Stillwater Complex was inaugurated in March 1987. A flotation concentration mill is in operation onsite, but the concentrates are currently shipped overseas for refining. The Bureau of Mines research provides alternative techniques for processing the concentrates and recovering the values should domestic recovery become desirable for economic or strategic reasons.
Paper in Precious & Rare Metal Tech., Elsevier, 1989, PP. 395-411