EFFECTS OF COMPOSITION AND GRANULOMETRY ON THERMAL CONDUCTIVITY OF ANODE COVER MATERIALS

摘要

Thermal conductivity of anode cover material is critical indetermining cell top heat loss. It has been observed that thermalconductivity of cover material is strongly dependent on packingand particle size distribution. Granular material that is denselypacked (lower voidage) has higher thermal conductivity. Whentwo sizes of spherical particles are mixed at various size ratios, thetheoretical voidage can be reduced from 0.4 to 0.2-0.3. This canbe applied to a particle system of crushed bath and alumina thatconstitute cover material. Currently, many smelters producecover material that is too fine with high voidages. This has theeffect of lowering the thermal conductivity which can causeunnecessary operational problems within the cell. Additionally,the effect of cover composition on thermal conductivity is notobvious. This paper describes studies conducted in the laboratoryto understand the effects of composition and voidage on thermalconductivity of cover material.