Optimisation of Chrome Retanning Process to the Garad (Acacia nilotica) Tanned Leather

Abstract

This study aimed to reduce the environmental pollution generated by chrome (chromium III salts) that result from the tannage processes of leather. It aimed also to encourage the use of a local tannin agent which is known as garad (Acacia nilotica). In Sudan, the majority of traditional artesian tanneries use garad for tanning. Some of the modern and mechanized tanneries use garad in the retannage stage. Twelve pieces pickled cattle hides were treated in pilot drum at speed of 8 rpm. In the experimental trail the pickled hides tanned with 30% garad and retanned with different offers of chrome (1%, 2%, 3%, 4%) followed by 10% garad. The chemical analysis of the leathers viz. for % moisture content, % ash content, % fat and % chrome contents were carried out for the experimental leathers. Physical testing, including thickness, tensile strength, percentage elongation at break, load at grain crack, load at grain burst and shrinkage temperature were measured. The chemical properties of leathers in all trials are found to be quite normal. The shrinkage temperature of experimental leathers for all trials found above 85.4°C and the tensile strength above 103.00 Kg/cm2.