Continuous pptn. of ions at high temp. and pressure - esp. where nickel and cobalt are pptd. as sulphide(s) when winning these metals from ores

摘要

Soln. of the ions is fed through an autoclave contg. one or more compartments. A reagent is added to the autoclave to ppte. the ions as a cpd. The resulting suspension is removed from the autoclave and fed down a vertical tower forming a separator for the solids and liq. A fluidising liq. is fed into the base of the tower so the fine particles (a) of the ppte. are driven up the tower to an outlet leading to the autoclave; particles (a) function as seeds for further pptn. of the ions. In the pref. process, the initial soln. contains NiSO4, and the reagent is H2S, so the ppte. is Ni sulphide. Used e.g. in the hydrometallurgical extn. of Ni and Co from laterite ores, where the fine sulphide ppte. is sepd. from the coarse ppte. and used as seeds in the autoclave.