Abstract
Vale Base Metals started operating the Long Harbour Refinery in 2014 using a novel hydrometallurgical process** to produce high purity electrolytic nickel, cobalt, and copper, from the nickel sulphide concentrate produced at the mining operation at Voisey’s Bay. Over the years, many challenges were successfully overcome. A particular area for attention was the pressure leaching circuit, where difficulties with plugging and corrosion of the autoclaves discharge dip pipes was frequent. The regular plugging and corrosion of these dip pipes resulted in reduced autoclave availability. In collaboration with Caldera Engineering, supplier of dip pipes, a non-metallic liner was developed and proved successful in addressing the operational difficulties. This improvement resulted in a reduction of unplanned downtime, lower replacement costs and increased safety. This paper reviews the evolution from problem to solution over the past 5 years of operation.
** Derek Kerfoot was the key driver for the research and development of the novel Pressure Oxidative Leach (POL) with direct nickel electrowinning process, ultimately commercialized at Long Harbour. Through a combination of deep hydrometallurgy knowledge, wide industry experience, persistence and perseverance, he helped turn a vision into reality.