IMMT Bhubaneswar develops tech to make refractory bricks from bauxite waste

CSIR institute develops process to convert mining waste into high-performance bricks, offering cost benefits and industrial applications across key sectors

Turning mining waste into industrial wealth, the Institute of Minerals and Materials Technology (IMMT), Bhubaneswar, has developed a technology to convert bauxite mining waste into high-performance refractory bricks, unlocking the potential of a long-neglected resource in mineral-rich Odisha.

 

In a significant innovation, the institute, which functions under the Council of Scientific and Industrial Research (CSIR), has utilised partially lateritised khondalite (PLK), a waste by-product of bauxite mining, to develop the refractory bricks. Typically considered low-value, this material contains a mix of silica, alumina, and iron oxides.

 

IMMT scientists have developed a multi-stage beneficiation and purification process to upgrade this waste into alumina-rich material suitable for refractory applications. The raw PLK rock typically contains 27–30 per cent silica (SiO₂), 35–40 per cent alumina (Al₂O₃), and 12–30 per cent iron oxides, along with traces of titanium oxides. 

   

The process begins with crushing the waste rock, followed by controlled reduction roasting, where temperature, time, and reductant concentration are optimised to alter the mineral phases. The roasted material is then ground into fine particles and subjected to low-intensity magnetic separation to remove strongly magnetic iron-bearing phases. 

Subsequently, wet high-intensity magnetic separation is employed to further reduce iron content to around 5–6 per cent. For achieving higher purity, the material undergoes acid leaching under controlled conditions, bringing iron impurities down to below 2 per cent. The final product has an improved composition, with alumina content ranging between 47–54 per cent and iron content reduced to as low as one per cent, making it suitable for high-temperature applications.

 

“The bricks developed can be compared with the standard 50 per cent alumina refractory bricks available in the market with respect to physical, chemical, mechanical, and thermal properties. The low iron content is a key advantage, as it improves high-temperature stability and resistance to corrosion and thermal shock — critical parameters for industrial furnace applications,” said Satyasish Rout, a researcher.

 

The institute has transferred the technology to Bhubaneswar-based Utkal Vanguard Engineering and Construction Pvt Ltd for commercial production. Ramanuj Narayan, director, IMMT, said Odisha is well known for its mineral resources, but there is another resource — mining waste — which has been neglected so far.

 

“IMMT has transferred a new technology to manufacture refractory bricks from bauxite industrial waste. The new brick that can withstand temperatures up to 1,400 degree Celsius has many industrial applications. Several such technologies are under development and those will be unveiled in due course of time,” he said.

 

The technology also offers a strong economic advantage. Rakesh Pati, managing director, Utkal Vanguard Engineering and Construction Pvt Ltd, said the company plans to establish a dedicated manufacturing unit in Khurda district.

 

“We have technology that is very cost-effective. The refractory bricks from industrial wastes can be manufactured at a cost of around ₹40 compared to the market price of ₹70 per piece. The bricks are expected to find wide usage across sectors, including steel, cement, glass, and aluminium manufacturing,” he told Business Standard.

 

India generates nearly 10 million tonnes of bauxite waste annually, much of which remains underutilised. By converting this waste into high-value industrial products, Ramanuj said the IMMT technology addresses both environmental concerns and raw material shortages. “The company is expected to scale up production and integrate the process into industrial operations, bridging the gap between laboratory innovation and market application,” he added.