Cathodoluminescence microscopy characterization of chrome-free refractories for copper smelting and converting furnaces

The results of an experimental program assessing the potential of several chrome-free refractory materials as potential replacements for the mag-chrome brick currently used in copper production furnaces are presented. Several commercial chrome-free bricks were subjected to the standard dip test in a high-copper calcium ferrite slag. The mineralogical changes in the bricks resulting from their interaction with the molten slag are described. The use of optical cathodoluminescence microscopy as an analytical tool is highlighted, along with reflected light microscopy and scanning electron microscopy-energy dispersive spectroscopy. Using the three tools together provides a description of the experimental results not achievable using one or two alone. The penetration resistance of the potential replacement refractories is comparable to that of mag-chrome, but the substitution of Fe2+ for Mg2+ in the periclase and spinel crystalline structures of the replacements reduces their corrosion resistance compared with mag-chrome, diminishing the likelihood that they will serve as reliable alternatives.