Salt-free curing of hides and skins and reducing the salt content of tannery effluents

摘要

Major benefits from the use of sodium silicate in leather manufacture have been researched and developed. The project - with the acronym "SILIC-SALT" - was funded under the EC programme INCO-DEV. Four important sets of findings were gained from this project: 1. Silicates can be successfully used for the long-term preservation of hides and skins, and the subsequent manufacture of commercially acceptable leathers. 2. Within leather processing: 2.1. Lime can be replaced by silicates within the liming and unhairing process. 2.2. An additional silicate penetrationeutralisation of pelts led to improved uptake of tanning and retannage agents, dyestuffs and fatliquoring - hence rationalised and cleaner processing. 2.3. The development of new trading commodities. 3. Silicates in tannery wastewaters are not detrimental to plant health. In contrast, common salt at levels normally found in tannery effluents is highly detrimental. 4. Information regarding silicate related chemistry, and interactions within leather manufacture at fundamental level. The background and the findings listed as 1 are presented in the following paper. Findings listed as 2, 3 and 4 are presented respectively as Parts 2, 3 and 4: these will be published in World Leather in April, May and June/July 2006. Each part presents the findings from that component of the investigation.