The development of a novel hydrometallurgical process for nickel and cobalt recovery from Goro laterite ore

Nickeliferous laterite ores constitute most of the world's known nickel and cobalt resources and will likely be the predominant source of new nickel land cobalt) in the future. Pressure acid leaching in horizontal agitated autoclaves is common to all new hydrometallurgical laterite treatment processes. Because only limited ore upgrading is possible, large volumes of relatively dilute leach solution are produced, containing about 5 g Ni/L and 0.5 g Co/L, as well as significant quantifies of Mg and Mn. The novel Goro solution treatment process involves the recovery of nickel and cobalt by solvent extraction with Cyanex(R) 301 directly from the partially neutralized leach solution (i.e. without prior upgrading step). Nickel, cobalt land zinc) are selectively extracted without the addition of a neutralizing agent The phase separation is excellent, and the organic losses are very low. Stripping with hydrochloric acid produces a solution about 20 times more concentrated, allowing for ready removal of Zn by ion-exchange and cobalt recovery by amine solvent extraction in much smaller circuits. A high purity nickel oxide product is recovered by pyro-hydrolysis from the amine solvent extraction raffinate. The coproduced hydrochloric acid is recycled to the Cyanex(R) 301 SX circuit for stripping. With low reagent and energy costs, the Gore process is expected to have a significant advantage over other processes recently commissioned in Western Australia.