Development of a Pickle-Free Chrome Tanning to Improve the Eco-Sustainability of Leather Processing

An alternative pickle-chrome tannage step with a lower inherent potential environmental impact than the traditional one was developed. The innovative process is based on the use of tanning products containing chrome(III) salts with less astringency than the traditional ones. The use of sodium chloride and sulfuric acid is avoided and a significant reduction of chlorides and sulphates dissolved in the exhaust baths is obtained. The technical feasibility of the innovative chrome tannage process was experimentally explored. Several experimental activities on a pilot scale have been performed, in order to assess the quality of the finished leather obtained by the new pickle-free tanning process. The results have shown that the finished leathers are comparable to the ones obtained by the traditional process in terms of physical-mechanical and technical properties. Besides, a LCA (Life Cycle Assessment) analysis was performed in order to check the actual reduction in environmental burdens due to the process proposed by the authors, in comparison with the traditional pickle-based one.