Development of High Alumina Synthetic Aggregate Based on Impure Raw Bauxite

The refractory industries in India are facing the challenges of unavailability of good quality raw materials, lack of continuous and assured supply as well as increased raw material price. It is difficult to produce high-quality refractory raw materials in the country due to the high impurity content in the available mineral resources such as bauxite, magnesite, etc. Hence, the manufacturing of premium refractory products is dependent on imports from China. On foot of its global commitment to reduce carbon emissions, the government of China has levied several restrictions on refractory raw material manufacturers which in turn affected production and deliveries. This in effect resulted in rising import costs and ultimately affected the cost of products. To circumvent this problem and to cater to the increasing domestic demand for quality products, an attempt has been made to explore ways and means to produce value-added products from the inferior quality raw bauxite available in India. The synthetic high alumina aggregates were manufactured by pyro-processing route from locally available bauxite, Bayer process alumina, and judiciously chosen additives. Extensive experimental work has been carried out to optimize the additive concentration and process to achieve the required properties in the aggregate. The produced synthetic aggregate is of superior quality with 93% Al2O3 & 5% porosity as compared to 86–89% Al2O3 obtained in Chinese bauxite. The refractory products manufactured using these aggregates have shown improved performance. Thus, the development of high alumina synthetic aggregates will open doors for the manufacturing of high-quality refractory products used for various customers like Iron and steel, Cement, Aluminium Industries, etc. As a result, the organization has reduced its dependency on the supply of Chinese bauxite.