Abstract

With the rapid development of the tanning industry, a large amount of chrome-containing filter residues produced by the utilisation of chrome-containing leather scraps has become an urgent problem needing to be solved. It is imperative to develop an environmentally friendly and efficient chrome-containing filter residue treatment technology.

In this study, a combination of high-temperature pyrolysis and chemical leaching was performed to resource utilisation of chrome-containing filter residue, and the leaching behaviour and kinetics mechanism of chrome extraction were investigated in detail. Under the following conditions: H2SO4 mass fraction of 40%, liquid-solid ratio of 8mL/g, leaching temperature of 90℃ and leaching time of 5 hours, the leaching rate of chrome could reach 87.86%. In addition, sour (pickled) skins tanned with a regenerated chrome tanning agent, which was produced from the leached chrome liquid, could reach a shrinkage temperature of 100.1°C. The results of kinetic analysis showed that the leaching process and pyrolysis filter residue were controlled by product layer diffusion and surface chemical reaction. The activation energy of the chrome leaching reaction was calculated to be 73.79 kJ/mol. This study provides a theoretical basis for the effective utilisation of chrome-containing filter residue in the leather industry.