AMMONIUM CHLORIDE PRODUCTION AND OPTIMIZATION OF BRINE AMMONIATION FOR LIME REMOVAL IN LEATHER PROCESSING

Leather industry occupies a place of prominence in Ethiopian economy in view of its massive potential for employment, growth and export. The need of import substituting leather processing chemicals from locally available feed stocks is an urgent matter both from economic and environmental point of view. One of the chemicals used in leather processing is ammonium chloride which is a deliming agent in Beam house operation. In this study, the production of ammonium chloride from proven available urea feed stocks ammonia, carbon dioxide and from the cheapest chlorine source sodium chloride which is readily available in Ethiopia, and its use and efficiency as a deliming chemical as compared to standard ammonium chloride is analyzed. A modified Solvay process approach was adopted in search of a route to the production of ammonium chloride locally. The method involves brine purification, ammoniated brine formation, carbonation of ammoniated brine, separation of sodium bicarbonate from ammonium chloride containing mother liquor, evaporation of ammonium chloride filtrate, cooling of the evaporated ammonium chloride filtrate to crystallize, centrifugation and drying of ammonium chloride which is collected as a white solid crystal of 98.5 - 99.5 wt.% NH4Cl. This preparation met the established specification for ammonium chloride of Indian Society for Testing and Materials (ISTM).