Flash smelting and converting furnaces: A 50 year retrospect

Abstract

1999 marked the 50th anniversary of the Outokumpu flash-smelting process. Originating during the post-World War II energy crisis, flash smelting is a high-intensity process developed to attain ever-increasing throughputs and intensities. Many innovations and continuous development ensued during the next 50 years before today's stateof-the-art copper-making process chain and environmental benchmarking technology (e.g., Outokumpu flash smelting, KennecottOutokumpu flash converting, and flash technology) became possible. This article reviews how Outokumpu flash furnace design, especially cooling for higher heat loads, has improved over the years.

Evolution of Size and Chemical Composition of Copper Concentrate Particles Oxidized Under Simulated Flash Smelting Conditions

“…It is noted that [1] and [2] represent the goal of the reaction chamber to produce matte. During the experiments, suspension-smelting conditions were established.…”

“…The solid feed rate was set to the lowest possible value provided by the vibratory feeder, which varied in the range of 3 to 5 g/min depending on the particle size of the feed material. Once the chemical composition of the concentrate particles was known and the solid feed rate was established, the stoichiometric amount of oxygen necessary to carry out reactions [1] and [2] was computed. The actual flow rate of oxygen gas supplied to the reactor was set to 1.3 times the stoichiometric amount, and that of nitrogen was calculated from a mass balance to satisfy the oxygen concentration to be tested in the run.…”

“…4CuSO 4 þ 2Fe 2 O 3 þ 4SO 2ðgÞ ½9 Upon ignition, it is likely that chalcopyrite oxidized according to reaction [1] to produce a mixture of copper and iron sulfides, i.e., copper matte. Further, under excess of oxygen in the laboratory reactor, the matte oxidized to form cuprospinel and copper oxide according to the following reaction [36] Cu 2 …”

“…It is noted that reactions [1] and [7] to [11] involve the loss of sulfur from the particles, whereas reactions [10] and [11] produce species with magnetic properties, i.e., cuprospinel (CuFe 2 O 4 ) and magnetite (Fe 3 O 4 ), respectively. Figures 13 and 14 show the evolution of the cumulative size distributions for fractions: < 45 and 45 to 53 lm, which are shown here as examples.…”

“…SINCE its commercial implementation in the past century, [1] the flash smelting process of copper concentrates has been the subject of continued research. This is because a number of phenomena occurring in the reaction shaft of the process are yet not well understood.…”