The Anglo American Corporation/University of British Columbia (AAC/UBC) chalcopyrite process: An integrated pilot-plant evaluation

摘要

The Anglo American Corporation/University of British Columbia (AAC/UBC) process is a medium-temperature leaching process for chalcopyrite concentrates. The concentrate is reground to fine size (P_(80) 5-20 μm) and leached under moderate pressure at 150°C in an acid-sulfate system. The addition of a surfactant disperses the molten elemental sulfur, avoiding passivation during leaching. Copper is recovered by solvent extraction (SX) and electrowinning (EW) to produce premium copper cathode. The process is distinguished by high copper extractions, hematite or jarosite formation for iron rejection, and elemental sulfur as the predominant reaction product. The process was evaluated in a continuous, fully integrated pilot-plant trial. The flowsheet comprised fine grinding of the concentrate, pressure leaching, thickening and filtration, copper SX/EW, with a bleed circuit to recover valuable base metal co-products. Gold was recovered from the autoclave residue by direct cyanidation. Copper and zinc extractions above 95% and elemental sulfur yields of 60% were achieved at 150°C in a 2-hour residence time. The presence of surfactants did not affect the extraction or the phase separation in the SX process. The gold extraction exceeded 80%. The AAC/UBC process is expected to be highly competitive with other hydrometallurgical copper processes under commercial development.