Influence of temperature and holding time on formation of hexavalent chromium during combustion of leather

Abstract

Previous studies indicated that Cr(VI) was not detected or was below 5 mg/kg in tanned leather scraps. However, after they are burned, the resulting ashes contain meaningful amounts of Cr(VI) that depend on the burning temperature. Furthermore, results obtained at the same ignition temperature, but different holding times, show high variability.(1-3) This paper presents experimental results that confirm the Cr(III) to Cr(VI) transformation during chromium tanned leather combustion and its dependence on temperature and time, thus finding an explanation for variability of the results published before.