Post-mortem Investigation of Magnesia-Chromium Brick Corrosion by Speiss in a Copper Smelting Furnace: Key Findings

This chapter delves into the post-mortem investigation of magnesia-chromium brick corrosion caused by speiss in copper smelting furnaces. The study focuses on the mechanisms of speiss infiltration and deposition, the effects on refractory lining integrity, and the chemical phase-equilibria involved. Key findings include the identification of significant degradation associated with the formation of complex magnesium-calcium-lead arsenates. The analysis of refractory-free and speiss-infiltrated samples reveals the gradation of speiss buildup and the impact of oxidizing conditions on refractory degradation. The study concludes that liquid speiss, due to its high density and reduced solidus temperature, effectively penetrates the refractory lining, leading to intergranular corrosion and reduced spalling resistance. This detailed examination provides valuable insights into the technical and environmental challenges faced in copper production, particularly with the increasing arsenic levels in feedstocks.