Kennecott Utah Copper Corporation

John F Castle

David B George

Philip J Gabb

Torstein Utigard

In a copper converting furnace, the (i) reduction of copper oxide in and the removal of copper metal from the slag, and (ii) conversion of copper sulfide in and the elimination of mineral waste from the blister copper is enhanced by introducing a gas, e.g. nitrogen, into at least one of the blister copper and slag such that the gas increases the turbulence or mixing at the blister copper/slag interface and promotes a lowering of the sulfur dioxide equilibrium pressure within the blister copper and slag phases. In one embodiment, the gas is introduced into both the molten blister copper and slag through a porous-wall injector.

Enhanced phase interaction at the interface of molten slag and blister copper, and an apparatus for promoting same

Copper matte is processed to anode copper without oxidizing blister copper in an anode furnace. Copper matte, in either molten or solid form, is fed to a continuous copper converting furnace in which it is converted to blister copper and slag. The blister copper and slag collect in the settler region of the furnace and separate into two phases, a blister copper phase and a slag phase (the latter floating upon the former). The converting furnace is equipped with means for stirring or agitating the interface of the blister copper and slag phases such that the sulfur content of the blister copper phase and the copper content of the slag phase are reduced.

Process and apparatus for the continuous refining of blister copper

A metallurgical furnace, preferably a metallurgical furnace for the production of copper, is equipped with a forebay. The forebay is in open communication with the settler of the furnace by a passageway that allows for the continuous removal of both slag and metal product, e.g. matte, blister copper, etc. The slag and metal product maintain their phase-separated relationship as they enter the forebay. The forebay is equipped with a weir that divides the forebay into a slag skimming chamber and a riser chamber. The slag skimming chamber has at least one slag overflow notch on at least one sidewall. The notch is located at an elevation on the sidewall such that only slag enters and is removed from the forebay. The notch is above the top surface of the metal product, i.e. it is above the interface between the slag and metal product layers. The weir is located downstream from the slag overflow notch, and it is positioned such that it acts as a dam to the slag but not the metal product, the latter of which underflows the weir and flows into the riser chamber. The molten metal product continuously overflows the end wall of the riser chamber through at least one metal product overflow notch into any means, e.g. a launder, tundish, etc. for transfer to another vessel (e.g. a holding furnace, an anode furnace, etc.).

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John F Castle