HydroCopper™ -: a new technology producing copper directly from concentrate

The direct leaching of copper concentrate instead of smelting will be beneficial and gain ground in the future. This paper presents the HydroCopper (TM) Technology, which is comprised of a chloride-leaching method for copper sulphide concentrates and the copper production up to semi-products. The technology is developed and registered by Outokumpu. The advantages of the brine solutions, compared with the generally used sulphate solutions, are the aggressiveness and stability of the copper(I) ion and, consequently, lower energy consumption in leaching and recovery. Copper(II) ions and oxygen are used as oxidants. Iron reports to the leaching residue as oxide and sulphur as elemental sulphur. Precious metals, An and Ag, are also dissolved and recovered. Copper(I) oxide is precipitated from the purified pregnant leach solution as an intermediate, which is further reduced with hydrogen before melting and casting into the final copper product. A unique feature of the HydroCopper (TM) process is the regeneration of the lixiviant, i.e., sodium chloride, using a chlor-alkali electrolyzer. The sodium hydroxide generated is used to precipitate copper(I) oxide, the chlorine gas in leaching, and hydrogen gas to reduce the copper(I) oxide. The reduced copper powder is melted and cast into copper semi-products. The HydroCopper (TM) process is capable of treating different kinds of copper concentrates and it is currently in the stage of commercialization. (c) 2004 Published by Elsevier B.V.