Influence of temperature and holding time on hexavalent chromium formationduring leather combustion

Previous studies indicated that Cr(VI) was not detected or was below 5 mg/k g in tanned leather scraps. However, after they are burned, the resulting a shes contain meaningful amounts of Cr(VI) that depend on the burning temper ature. 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 dependenc e on temperature and time, thus finding an explanation for variability of t he results published before.