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Title: DELIMING OF UN-BOUNDED AND BOUNDED LIME FROM WHITE HIDE

Author
item KOLOMAZNIK, KARL - TOMAS BATA UNIVERSITY
item BAILEY, DAVID - BAILEY CONSULTING
item Taylor, Maryann

Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2006
Publication Date: 5/1/2007
Citation: Kolomaznik, K., Bailey, D.G., Taylor, M.M. 2007. Deliming of un-bounded and bounded lime from white hide. Journal of American Leather Chemists Association. 102(5):158-163.

Interpretive Summary: During the processing of hides to leather, the lime which had been applied to the hide during the unhairing step needs to be reduced. Traditionally, this lime has been extracted chemically. In order to have a more environmentally benign deliming (less chemicals and water usage, lower cost), we investigated the potential of sequentially washing the hides in pure water followed by an application of an appropriate deliming solution, both of which will ultimately remove the unbound lime as well as bound lime. Thus, the objective of this study was to determine the optimal wash parameters as well as chemical additions using a mathematical physical process model. The absorption and diffusion of bound and unbound lime were determined experimentally. The information obtained from these experiments was inserted into the process model and the most economical process parameters for deliming were determined.

Technical Abstract: In a typical white hide deliming operation, unbound lime as well as bound lime are removed using both water and chemicals; optimization of this operation is highly desirable. The objective of this study is to determine when it is suitable to interrupt washing with pure water (non-chemical deliming) and replace it with washing with an aqueous solution of a deliming agent (chemical deliming). We developed a mathematical-physical process model that presents a feasible solution to the above mentioned question. Experimental determinations of the sorption isotherm as well as the effective diffusion coefficients are presented. Both economical and technological parameters provide input data for a computer program.