Treatment of sheepskin chrome shavings. Isolation of high value protein products and reuse of chromium in the tanning process

During the last few years we have demonstrated that cattle hide chrome shav ings, a waste coming from the leather industry, can be treated to isolate p rotein products and chrome sulfate. In Spain and in many other countries, t he production of sheepskins is as important as the production of cattle hid es. In this paper, the conversion of sheepskin chrome shavings to gelatin, hydrolysate and chrome sulfate is presented as are the chemical and physica l properties of these products. The suitability of recovered chrome sulfate as a tanning agent was demonstrated by the tannage of pickled sheepskins, using matched sides comparisons; results are given for runs employing vario us properties of of recycled to commercial chromium. Chemical analyses in t he wet blue stage and three different physical tests in the crust stage wer e performed on all the leather samples to evaluate the tannage. The results show that there were no significant differences in the leather that had be en tanned with either the commercial chromium or the recycled chromium.