Abstract

In this paper we describe the construction of a mathematical model of washing and of soaking salted raw hide materials. The methodology corresponds to the use of the chemical engineering methods in tannery research. The possibilities of binding the sodium chloride to hide substance, the mechanics of sodium chloride transfer in the hide under the conditions of swelling taking place during the process, and the washing out of soluble proteins have been considered. The mathematical model is proposed on the basis of the following presumptions: the sodium chloride sorption of the hide substance is small and may be simply neglected, the mass transfer in the hide under laboratory conditions occurs by a diffusion mechanism. The diffusion occurs along the actual pore length, and the same is very little altered by swelling. A lower velocity of sodium chloride removal is observed in the case of a hide with high degree of dry matter, because of the closed structure due to agglutination resulting from over-drying, and also in the case of a hide with increased quantities of fat on the flesh side.