Removal of MgO from the Chrome Cake Produced by Enzymatic Hydrolysis of Chrome Shavings

Abstract

The tanning industry processes raw hides and converts them into leather, producing considerable quantities of solid and liquid by-products. The solid tanned by-products contain chromium and by-product liquors contain residual chromium. In order to prevent loss of protein material and chrome compounds, technologies were developed for recycling liquid and solid by-products. Recycling solid by-products is being successfully realized through enzymatic hydrolysis. The chrome cake remains an issue as it contains MgO which was used as a promoter in hydrolysis of chrometanned solid by-products. High content of MgO in the chrome cake complicates its further use. This presents work addresses the possibility of isolating magnesium, present as hydroxide, from the chrome cake using by-product (spent) tanning liquor. Results showed that it is possible to achieve magnesium removal efficiency up to 70 %.