New Delhi: Researchers from the National Institute of Technology (NIT) Rourkela have developed an eco-friendly method to produce black terracotta wares.
The patented sustainable production process reduces the total firing process from two days to less than seven hours without any adverse impact on the health of working associates and the climate, said the Institute on Monday.
The current production method typically requires two days to complete the open-pit firing process, which releases smoke containing many toxic gases, such as carbon monoxide, carbon dioxide, sulphur oxides, and nitrogen oxides, that adversely affect the health of associated workers, including breathing difficulties.
“The sustainable production process merges traditional artisan knowledge with modern technology. The key to this process is the indirect heating of as-fabricated bodies in an enclosed vacuum (air-depleted) chamber,” said Prof. Swadesh Kumar Pratihar, Professor, Ceramic Engineering, NIT Rourkela.
“During this heating, pyrolysis of the carbonaceous oil produces carbon monoxide and carbon soot, which helps in producing the reducing atmosphere required for the development of back colour wares,” he added.
The novel method produces a uniform black finish and does not require open fires, skilled workers, or specialised clay.
The process significantly shortens the firing cycle and eliminates environmental pollution associated with burning large quantities of organic materials. Unlike older methods, this approach can be a key technology to produce black terracotta wares, anywhere.
The process makes a significant contribution to environmental conservation and heritage preservation.
Black pottery is made in India and its neighbouring regions using techniques that are generations old.
One such example is the Nizamabad Black Pottery of Uttar Pradesh, where semi-finished wares are coated with a glaze made of clay and organic vegetable matter native to the area, referred to as ‘kabiz’.
Polishing with mustard oil gives the surface a mirror finish. It is then fired in a sealed iron vessel along with cow dung, straw, and wood chips.
IANS
