Chemical wear mechanism of magnesia-chromite refractory for an oxygen bottom-blown copper-smelting furnace: A post-mortem analysis

Abstract

Oxygen bottom-blown smelting technology (SKS) is a promising way to utilize the low-grade and complex multimetallic copper ores. To reveal the wear mechanisms of the furnace linings, a post-mortem study of the used refractories (fused-grain rebonded magnesia-chromite refractory) was carried out by chemical and microstructural analysis. The results showed that the chemical interaction at the bath-lining interface was particularly strong since thick corrosion layers (around 4.0 cm) were generated, where a continuously distributed phase of forsterite was identified. This was mainly owing to the high injection pressure and the presence of Cu-CuxO melts in the slag, which greatly accelerated the slag infiltration and periclase dissolution. In this case, fused grains with a high content of intergranular spinel were found more difficult to be corroded by the slag. The significant loss of direct bonds and the softening of refractory are considered as the main degradation mechanisms for the SKS furnace linings. The interaction between FexO in slag and chromite spinel was evident, but it only occurred in the areas near the hot face, showing limited effect on the corrosion behavior.