Formation of copper chromite in chrome ? Magnesite refractories during service in copper-smelters

Abstract

Copper chromite in chrome — magnesite refractories during service in copper-smelting units can form both on account of free copper oxide separating from the natural chromite without decomposition of the remaining solid solution, and also as a result of the decomposition of the original chromite during its reaction with a mixture of copper oxides and silica with the formation of copper chromite and magnesium silicates. Upon the reaction between the spinel MgO · Cr2O3 of stoichiometric composition only with CuO of the solid solutions, the copper spinel CuO · Cr2O3 and copper chromite Cu2O · Cr2O3 are not formed. With a mixture of magnesite — chromite, copper oxide, and silica a reaction occurs during heating with the formation of copper chromite and magnesium silicate. On the basis of the experimental data obtained it can be concluded that increasing the concentration of free silica in copper-smelting slags is undesirable, since this is a cause of the intensive chemical wear of chrome — magnesite linings in copper smelting furnaces.