Abstract

The present study was aimed to increase the mass transfer rate inside leather, thus allowing the use of concentrated solutions and consequently a reduction in pollutant quantities. Alaboratory installation for wet processing and tanning leather was conceived and put into operation. It is based on the almost instantaneous absorption of the processing solutions by the compressed leather after the compression is removed. The possibility of applying the countercurrent process for pickling and chromium fixing inside the leather was studied.

The process parameters taken into consideration were: the concentration and the basicity of the basic chromium sulphate solutions, the intermediate basification of the solution, the intensity, frequency and number of pressing operations, the insertion of rest periods between the pressing operations, the partial removal of pickling solutions before the treatment with chromium solutions. The treated leather was analysed for total, soluble and fixed chromium, stratigraphic distribution, shrinkage index and moisture content were determined. Some correlations between the process parameters and the final leather characteristics were determined.