New CSIR-NIIST tech turns waste to wealth

T'puram: A new technology to make strong bricks, paving tiles, interlocks and other construction products using waste sand byproducts has been developed at CSIR-NIIST (National Institute for Interdisciplinary Science and Technology) as part of the waste-to-wealth programme.The institute tied up with a private company to set up a unit to produce 5,000 bricks per day using 30 tonnes of waste sand or spent moulding sand from alloy casting companies. This waste material is formed from used sand not suitable for making moulds due to high temperature and chemical reactions from molten metal, which will be sourced from foundries in Kerala and Tamil Nadu. The sand-based moulds are used to pour molten metal and cast products at these metal factories.The move will also help the foundries recycle the byproduct, which used to end up in landfills. The project will also be of use to the construction sector, which is facing a shortage of natural raw materials.The institute developed the process to make bricks by studying the reactivity of foundry waste sand with cement, lime, gypsum and polymer-modified binders. CSIR-NIIST provided technical assistance to procure the machinery and design the plant.The biggest advantage of the brick products is that they avoid the usage of natural raw materials like clay, M-Sand and gravel. The cement bonding and compression moulding produce high-strength bricks as per the IS 1077 standards. The bricks can also be shaped in aesthetically appealing colours for architectural interior design.The institute expects that this brick production plant will directly benefit the housing projects of the state and central govts. The technology is expected to be an environmentally friendly process.CSIR-NIIST director C Anandharamakrishnan said, "This technology exemplifies the institute's commitment to developing sustainable and circular economy solutions for the country's industrial ecosystem. By transforming foundry waste into high-value construction materials, we are not only addressing an environmental challenge but also creating an opportunity for industry to participate in nation-building through green innovation."The process was designed as part of the ‘Waste to Wealth' research programme identified by CSIR under the vertical industrial solids waste management. As part of this theme, CSIR-NIIST proposed an idea of effectively utilizing the various industrial wastes for construction applications to preserve the fast-depleting natural resources by the construction sectors. "Foundry sand waste is a byproduct, regularly generated in bulk from the metal casting industries, and the utilisation of this byproduct to develop building materials has been seriously considered," the institute said.