Selenium partitioning between slag and matte during smelting

Abstract

Copper concentrates usually contain a number of minor as well as precious elements, the control of which in copper smelting processes is often a key to the quality of the anode copper produced and may also have a bearing on the overall economics of the process. During copper smelting, the copper concentrates are partially oxidized to form slag and matte. The molten slag and matte are separated from each other in the settler. The matte being heavier in density settles at the bottom of the furnace and slag being lighter in density floats over the matte and is eventually discarded off. During the separation, selenium is distributed between slag and matte. Selenium is a value added by-product of copper process. The lower recovery of selenium from the copper process is attributed to the high loss of selenium to the discarded slag. Knowledge of the distribution and form of selenium in slag and matte is very important in the control of the selenium loss, although to date very little is known regarding their distribution. The samples of slag and matte were collected from the smelter exit before their separation. Selenium was added in different proportions in the sample. The experiments involving slag-matte separation were performed at 1250°C for 4 hours of soaking time under inert atmosphere in a vertical tubular furnace. The distribution of selenium and the mechanism by which selenium is dissolved in matte and slag have been established by this study.