Treating Leather Shaving Waste to Decrease Its Environmental Impact

Abstract

hrome shaving waste (CSW) is one of the largest leather tanning wastes, caused an economical and environmental loss if it did not utilize properly. This study aims to extract chromium from chrome shaving waste, by alkaline hydrolysis or incineration in order to reuse it in leather tanning. Sodium hydroxide and carbonate were used in chemical hydrolysis and compared with incineration method in chrome yielding. Twenty five sheep pelts were tanned with recovered and commercial chromium 33% basicity to compare their effects in tanning. The results showed that among alkaline treatments, caustic soda was more effective than sodium carbonate in extraction, but incineration method was the best extraction method because of its high extraction yield (99.37%). Using sugar as a reducing agent was better than sodium sulphite to prepare tanning liquor. It increased chrome yield and produced chromium sulphate 33% basicity, which are more suitable for leather tanning. Most physical and chemical properties, except fat and ash contents, were similar in leathers tanned with recovered chrome and those tanned with commercial chrome. Thus, all studied tanned leathers were suitable for using in leather manufacturing.