Mass transfer through the gas phase during the firing and service of periclase refractories in a tunnel kiln

Conclusions There is a substantial transfer of material through the gas phase during the firing of periclase articles at 750–1800°C in a tunnel kiln. From the investigation of the condensate deposits on the lining surface and in the pores of the bricks, we detected both the typical (ordinary) and the new phases and compounds for these conditions: thenardite, meta-thenardite, Na₂SO₄ of forms I and III, langbeinite, vanthoffite, 3Na₂SO₄·MgSO₄, sulfates of magnesium and calcium, chromates of potassium, sodium and calcium, their solid solutions, periclase, spinel, of variable composition, chromium oxide (III). The mass transfer through the gaseous phase affects the structure change in the refractories and the character of their wear in service, which must be considered in the development of new refractories for the linings of high-temperature tunnel kilns.Translated from Ogneupory, No. 7, pp. 23–28, July, 1981.