India: Madras Cements is to set up limestone beneficiation plants to help it improve its cement raw material resources and extend the lifespan of its limestone mines. Once the beneficiation plant is in place, low-grade limestone will be processed to 12.5% SiO2 content. The cement plant will then use equal quantities of beneficiated and high grade limestone.
Madras will install the first of such plant at a cost of US$5m at Alathiyur in Tamil Nadu, where it has a 3Mt/yr cement plant. Once the 400t/hr beneficiation unit is stabilised, the company will establish similar facilities at other plants, according to A V Dharmakrishnan, Mardas' CEO. He said that, following the installation of the plants, the company will be able to avoid wasting huge quantities of its limestone supplies, extending the life of its limestone quarries.
Currently Madras' limestone can have up to 30% SiO2 content can be as high as 30%. It is either rejected or blended with high-quality limestone (8% SiO2) purchased from an outside source.