An estimation of purity and yield in purification of crystalline layers by sweating operations

Sweating operations were explored for various crystalline layers obtained during layer-melt crystallizations. The crystalline layers used in sweating operations were crystallized at different cooling rates of 0.1, 1, and 5K/min, and different feed compositions of 80, 85, and 90 wt% caprolactam-cyclo hexanone mixtures. The purification effects of sweating parameters, including the sweating time, amount of inclusions entrapped during the crystallization operation, and the degree of superheating, were investigated. The effect of crystalline layers, formed under various crystallization conditions, on sweating was studied. A model combining heat-balance equation and mass transfer correlation for the movement of inclusions was developed. The model was verified with the experimental data.