Résumé : |
Tannery effluent containing chrome is one of the most troublesome problems, in the leather industry. The author has tried to develop a new process to resolve the problem and has found it possible to select a water-immiscible organic solvent, such as "light wax", to serve as the carrier. The chrome powder is not soluble in the carrier solvent but, by virtue of the small quantity of water held in the pelts, the chrome powder dissolves therein and penetrates quickly through the whole thickness of the pelts. The solvent can be used, repeatedly, without any other treatment.
After tanning, the solvent is separated readily on standing so that no chrome pollution is discharged. The equipment is simple, the technique is easy, the quality of the finished leather is excellent, the cost is reasonable and, finally, chrome contamination can be avoided. In addition, the water-immiscible organic solvent carrier provides a cushioning action such that the pelts can be rotated smoothly and as freely as in aqueous media. Since the bath is virtually dry, this method is described as "dry tannage in solvent media". |