Recovery of copper values from iron-containing ore materials as mined and smelted

Abstract

A process for improving overall recovery of copper from an integrated mining and metallurgical processing operation by utilizing iron-containing copper ore materials as mined, such as low-grade copper ores and mine wastes, and crushed or granulated copper-containing slag obtained by smelting the higher-grade portions of such ore materials, involves the minign of such ore materials, the smelting of higher grade portions thereof, and the leaching of copper values from lower grade portions thereof with an aqueous, weakly acidic lixiviant to produce an acidic, ferric, effluent solution. The smelter slag is leached with the such effluent solution and copper values are recovered from the resulting pregnant solution. If desired, the barren solution may be recycled to the initial ore leaching step. By maintaining the pH of the acidic, ferric effluent solution from the initial leach within its normal range of about 1.9 to 3.0 for the slag leaching step, copper is selectively leached from the smelting slag while avoiding the usual precipitation of ferric salts and the formation of gelatinous slag decrepitation products. Moreover, ferric ion values in the acidic, ferric effluent solution from the initial leach are significantly reduced during laching of the smelter slag, thereby significantly increasing the efficiency of copper recovery in a subsequent step of either cementation of copper on metallic iron or electro-winning of copper.

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