Inco's oxygen top-blowing, nitrogen bottom-stirring (TBBS) technology for converting chalcocite to 'semi-blister'

摘要

In 1993/1994, Inco Limited commissioned a new flowsheet in the Copper Cliff smelter that processes a bulk Cu-Ni concentrate (11% Cu, 9% Ni) through two Inco flash furnaces. A new acid plant was built and, as a result of various changes, SO_2 emissions were reduced from 685 kt/y to <265 kt/y. Following flash smelting and converting of the bulk concentrate, all of Inco's copper reports to a low-iron (<0.6%) bulk (copper-nickel) converter matte that is cooled under controlled conditions. The Cu is separated from the Ni by flotation into a nickel-contaminated chalcocite concentrate (MK), analyzing ～74% Cu, 4% Ni. Inco originally planned to flash convert this material to semi-blister (sulphur-saturated, nickel-contaminated copper). However, potential operating problems observed during extensive flash converting pilot plant trials in 1988-1991 led to the development of an alternative oxygen top-blowing, nitrogen bottom-stirring (TBBS) technology for converting MK to semi-blister. The semi-blister is subsequently refined to blister and anode copper in additional vessels. This paper describes the development, commercialization and subsequent continuous improvement of Inco's TBBS process for converting chalcocite concentrate to semi-blister.