Granulation as it Pertains to Electric Furnace Matte, Converter Slag, and Converter Matte in a PGM Smelter

This paper explores the granulation processes relevant to electric furnace matte, converter slag, and converter matte within the context of the Precious Metals Smelter operated by Stillwater Mining Company in Columbus, Montana. The objective is to evaluate improvements in the handling and processing of molten materials in the smelting process. Methodologically, the authors detail the use of a 7.5 megawatt electric furnace and Top Blown Rotary Converters (TBRC) for processing both mine-derived and recycled Platinum Group Metal (PGM) bearing materials. Observations indicate that significant advancements have been made in granulation efficiency, specifically in minimizing rapid steam explosions in the granulation launder. Results show that innovations in process controls and operational efficiencies have led to enhanced recovery of precious metals and an extended lifespan for granulation pumps, with replacement frequency improved from every three weeks to every six months. Overall, the findings underscore the successful integration of filtration systems and optimized operational protocols in achieving higher performance in the granulation of TBRC slag and matte, contributing to both economic and environmental benefits for the smelting operation.