Sterlite's copper slag waste finds new uses

Anil Agarwal-promoted Sterlite Industries India Ltd (SIIL) is planning to convert a waste product of its copper smelting plant at Tuticorin – copper slag — into an alternative material for concrete applications.

The company has already started supplying the material to cement manufacturers and now wants to focus on road, abrasives and other industries.

The Tuticorin plant of Sterlite has a capacity of 400,000 tonnes per annum and the company plans to double it with an investment of Rs 2,500 crore. The key raw material for copper smelter is copper concentrate which mainly consists of copper, iron and sulphur. During the smelting operation, iron is removed as iron silicate, which is known commonly known as copper slag (ferro sand).

As per scientific estimate, for every tonne of copper metal produced, around 1.8-2.2 tonnes of slag is generated, according to Ramesh Nair, chief operating officer, Sterlite Industries India Ltd.

“With increasing scarcity of river sand and natural aggregates across the country, construction sector is under tremendous pressure to explore alternative to these basic construction material to meeting growing demand of infrastructure demands,” he said.

In states like Kerala, Maharashtra and Gujarat, sand mining in rivers has already been banned owing to its disastrous impact ecology. “Therefore, slag has a big potential of getting developed as a suitable alternative material to these resources. It is a new business avenue for us and we are going to make revenue out of waste,” said Nair.

At present, across the world around 33 tonnes of slag is generated while in India three copper producers Sterlite, Birla Copper and Hindustan Copper produce around 6-6.5 tonnes of slag at different sites.

According to Nair, the slag is highly stable and non-leachable in nature. The utility of copper slag as alternative material for other industrial / sectoral application has been vastly explored in the last one decade.