MENU

Less hazardous salts for leather processing

Project is focused on the leather technology development using less hazardous salts: sulfides and chromium. The project aims to meet the demands of increasing market for new environmental technologies and high quality products.

Eco-labels are used to guarantee the consumer a product meets certain minimum standards in relation to its environmental impact during production, use or disposal, and to distinguish the product from competitors in a positive way. The conventional method for making the skins and hides ready for tanning and the tanning by itself employs a wide variety of chemicals which results in an increase in chemical oxygen demand (COD), total dissolved solids (TDS), chlorides, sulfates and chromium in the tannery effluents. Waste costs of the EU leather tanning company's make up about 5% of turnover. Beamhouse and tanning processes alone contributed more than 90% of the total pollution from leather processing. In most of the leather beamhouse and tanning processes the salts eg., sodium chloride, sodium carbonate, sodium sulfide, ammonia sulfate, chromium salts are used. One of the biggest disadvantages in leather industry is the use of sodium sulfide and chromium salts. The elimination of even small amount of those salts from the wastewaters it is considered as a positive achievement. There are two main possibilities allowing to solve the problem of hazardous salts. First of them is the development of unhairing systems containing other alkalies and unhairing agents. Alkalies as sodium hydroxide, sodium carbonate, sodium sulfite and unhairing agents as amines, tioglycolates, chlorites, peroxydes, peracids and enzymes can be used in such a case. On the other hand, several materials mentioned above are not less dangerous than sodium sulfide. The use of systems containing enzymes is one of the most promising methods to decrease the environmental damage caused by leather processing. The second it is the development of chrome free tanning. At the beginning of the last century the development of the chrome tannage gave new possibilities to produce a commercial trading product called wet-blue. Chrome tanning is a versatile tanning system, but the pollution problems of chromium due to inadequacy of treatment systems and possible formation of Cr(VI), a carcinogen, have led to search for an eco-friendly and viable alternative tanning system. In this case the most suitable alternative is tanning with other chrome free materials. Thought the low thermal stability mostly is used a combination tannage based on vegetable tannins and co-tanning adjuncts eg., aluminium and silicate. Such leather tanning systems gives the possibility to produce articles for anti-allergy leather. So, the growing global concern on environmental health is forcing leather processing industry to adopt greener and cleaner manufacturing practises. Conventionally, leather manufacture involves multi-step processing such as beamhouse operation, tanning, post-tanning and finishing. Even though this multi-step processing followed for centuries is logical, it will be highly beneficial if there would be a possibility of integrating any of these steps. So, mostly of researchers attempt to integrate one process into the conventional technologies. This project will combine all processes in one complete system - new leather processing technology, which could propose to leather market the product with excellent quality indexes named as eco-leather. The environmental impact of the unhairing and tanning processes will be estimated and evaluated. The main purpose and challenge of this work will be to combine both leather processing steps into one technique. The new technology will be designed to get the new safe product for customers and to offer important environmental advantages. The leather industry, especially in developed countries, has provided economic benefits but suffers from a negative image due to environmental impact (the new technologies are more expensive and ecological indexes of wastewaters do not decrease considerably), requires new equipment eg. for deliming using carbon dioxide. However, ever-increasing environmental costs related to treatment, disposal and taxes and external pressures will serve as an incentive to use new methods on a broader scale. Therefore, new environmental friendly technologies are required. The main objective of the project is: development of new unhairing systems significantly decreasing consumption or even refusing the usage of sulfides to improve wastewater quality and new tanning systems containing chrome free materials, and the coordinating of both processes in order to obtain a leather with high thermal stability and resistance characteristics similar to those of the chrome tanned leather.
Acronym: 
SALTLESS LEATHER
Project ID: 
5 897
Start date: 
03-08-2011
Project Duration: 
36months
Project costs: 
790 000.00€
Technological Area: 
Tanned leather process related to Footwear / Leather Technology
Market Area: 
Textiles (synthetic and natural)

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.