Post-mortem Study of Magnesia-Chromite Refractory Used in a Submerged Arc Furnace in the Copper-Making Process

The periodical relining of furnaces because of refractory wear is a cost driver in the copper-making industry. This paper presents a post-mortem study of the refractory lining of a submerged arc furnace used in slag-cleaning operations at the Atlantic Copper Smelter (Spain) after a 6-year campaign. Samples were taken from different locations in the area in contact with slag and analyzed using a scanning electron microscope equipped with an energy dispersive spectroscopy system. New phases were generated as a consequence of the chemical interaction between the molten slag in the bath and the magnesia-chromite refractory lining. The chemical dissolution of the magnesia of the refractory and the incorporation of iron from the slag in the refractory phases were the main drivers. From this interaction, a reaction layer on the hot face of the refractory was formed, whose properties differ from the as-delivered refractory.