Regulating the pore structure of periclase refractories by adding Y2O3 to enhance corrosion resistance for copper slag

The penetration of copper-smelting slag into refractories is a major challenge to the research of chromium-free refractories for copper-smelting furnace. In this paper, Y2O3 was added to regulate the pore structure of periclase refractories, which enhanced their various properties, especially corrosion resistance to copper converter slag. The results showed that the periclase refractories doped with 1.0 wt.% Y2O3 (1Y sample) possessed the optimum properties. Compared to the sample without Y2O3, the apparent porosity of 1Y sample was decreased by 7.3%, and its average pore diameter was only 3.7 mu m. The addition of Y2O3 filled the pores among MgO grains and promoted the expansion of high melting point silicates, thereby reducing the pore size and causing more complex pore structures. This was beneficial to improving the corrosion resistance of periclase to copper slag, especially to prevent the penetration of Cu-x(+) and Na+. After static slag corrosion, the permeability index was significantly decreased by 41% compared to periclase refractories without Y2O3. Moreover, compared to industrial MgO-Cr2O3 refractories, the 1Y sample possessed better resistance to copper slag erosion based on rotating finger tests, and its permeability index and penetration depth decreased by almost 50%.