RECOVERY OF COPPER FROMAMASSIVE POLYMETALLIC SULPHIDE BY HIGH CONCENTRATION CHLORIDE LEACHING

AbstractA new process for the recovery of copper and associated base metals from a polymetallic massive sulphide ore is described. The massive sulphide contains copper and especially nickel sulphide in a mineralogical form which negates both good recovery and high grades in concentrates using conventional flotation methods. Utilizing the properties of high concentration chloride brines, a hydrometallurgical flowsheet has been developed and tested whereby the recovery of all of the metals and some of the power requirements for the plant itself can be derived from the ore. The new process involves leaching of the whole ore in two stages: 1) a primary leach during which the pyrrhotite is leached with HCl assisted by MgCl2 to yield hydrogen sulphide (from which energy is produced) and 2) a ferrous chloride solution; a secondary ferric chloride/MgCl2 oxidizing leach during which the economic metals (C, Ni and Co) are solubilized. The generated primary ferrous chloride leach solution is subjected to oxidation a...