Viscosity of oxyfluoride melts relevant to the deterioration of refrac tory linings in aluminium reduction cells

Molten fluoride attak on refractory pot linings increases the energy consumption and may in extreme cases terminate the pot life. The pene tration depth of the molten fluorides is determined by phase equilibr ia and the viscosity of molten mixtures of fluorides and sodium alumi nosilicates. the viscosity is estimated using a semi-empirical theory which relates the viscosity to the heat capacity of supercooled melt s near the glass transition. The viscosity of the fluorides is increa sing several orders of magnitude when albite or mixtures of albite an d nepheline are dissolved in the molten fluorides. The present findin gs demonstrate that the penetration of molten fluorides in traditiona l fire clay linings is strongly retarded due to the formation of a vi scous sodium aluminosilicates is discussed in terms of the silicacont ent in the fire clay materials and finally in relation to refractory materials of calcium and magnesium silicates.