An high exhaustion tanning process
Today, 80-90% of leathers in the world are tanned by chrome tanning. Chrome tanning uses a solution of chemicals, acids and salts (including chromium sulphate) to tan the hide. It’s a very quick process, taking about a day to produce a piece of tanned leather. First hide are limed to remove hair and then are “pickled” by being left in the acid salt mixture, before being placed in the chromium sulphate. All hides then come out looking light blue (known as “wet blue”).
In 2008, about 24 million tonnes of chromium was produced. About 2% of it has been used for the production of chromium sales, such as chromium sulphate, for the making of leather tanning materials but also for the production of dyestuffs and plastics. Worldwide approximately 480,000 tons of chromium tannins are produced per year.
The most important chrome deposits are found in South Africa accounting for 33% of production, while India and Kazakhstan provided 20% and 17% respectively. Brazil, Finland, Oman, Russia, and Turkey together contributed a further 21%, while some 12 smaller producer countries brought the balance of 9%.
The increasing requirements of producing safer chrome leathers in a sustainable way have led Silvateam to develop an innovative hybrid tannage using a combination of chrome salts and Blancotan CAT that allows the customer to produce a new environmental friendly wet blue.
Main advantages of hybrid chrome tanning compared to standard chrome tanning
- Very low environmental impact
- High percent of Cr2O3 fixed to the leather fibres
- Extremely light wet blue leather colours
- Uniform and excellent fullness of leathers
- Chrome free sludges
- Versatile hybrid wet blue leather
- Leathers with a more performing dyeing characteristics compared to standard wet blue
- Reduced chances of chrome (VI) formation