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

摘要

Thermal conductivity of anode cover material is critical in determining cell top heat loss. It has been observed that thermal conductivity of cover material is strongly dependent on packing and particle size distribution. Granular material that is densely packed (lower voidage) has higher thermal conductivity. When two sizes of spherical particles are mixed at various size ratios, the theoretical voidage can be reduced from 0.4 to 0.2-0.3. This can be applied to a particle system of crushed bath and alumina that constitute cover material. Currently, many smelters produce cover material that is too fine with high voidages. This has the effect of lowering the thermal conductivity which can cause unnecessary operational problems within the cell. Additionally, the effect of cover composition on thermal conductivity is not obvious. This paper describes studies conducted in the laboratory to understand the effects of composition and voidage on thermal conductivity of cover material.