Benefits of Recycling of Pickling and Chrome Solutions

Abstract

This work was undertaken to investigate the applicability of recycling pickling and chrome solutions in order to save chemicals and protect the environment from there polluted solutions. Experimental work which was investigated through statistical analysis shows that the PH and salt content are quite significant and must be always maintained at the standard levels of 2.2 and 3.0 as shown in tables 4.1 and 4.2. The solutions were recycled for seven runs, each run was adjusted to the required levels as shown in tables 4.4, 4.5 and 4.6, the leather produced was subject to both physical and chemical analysis, the results which are shown in tables 4.9 and 4.10, agreed with the standard specifications of these types of leathers which are in the range of (e.g. tensile strength 200- 210gr/cm). No work has so far been carried out for recycling of picking solutions. Previous work (Tuck 1981) used the picking solution for chrome tannage and adjusted the chromebath accordingly. On the other hand the process of recycling picking solution was delayed to be carried out in chrome tanning stage. (F) Seven runs were investigated, in each run the spent liquor was analyzed for Cr2 O3 content and the results are shown in tables 4.7 and 4.8. The solution was adjusted to the required level and the process of tannage was continued until completion. The leather produced was processed from chrome tannage through shaving, retannage, drying to finishing. The leather produced was subjected to physical and chemical analysis which were satisfactory as compared to the standard specifications of the British Official Methods of specifications (JSLTC, 2002). It is concluded that both picking and chrome solutions can be recycled indefinitely without loss of quality. The saving in chemicals is 60%, and 90% of water float, no liquid wastes need to be discharged giving a clean environment. (