Researchers at the Indian Institutes of Technology (IIT) Madras and Kanpur have devised a method for converting waste from iron ore mining into an environmentally acceptable material that can be utilized by industry.
Through a microwave-assisted beneficiation method, the researchers worked with NMDC and JSW Steel to convert slime into iron-rich materials suited for blast furnace charge. The technique is cost-effective because the microwave preferentially interacts with iron oxides or carbon mixtures while excluding other impurities (such as silica, alumina, and phosphorus oxides) and rapidly heating the material compared to conventional approaches, saving a substantial amount of energy and pollutants.
This initiative is important to India because particles smaller than 0.15 mm are created during the processing of iron ore and are thrown as waste known as slime. Slime produced during mining accounts for approximately 20-25% of total iron ore feed and is deposited between iron-bearing mountain ranges.
Years of mining have resulted in massive slime ponds with millions of tonnes of trapped iron content. Aside from being ineffective, the slime may harm the land and ecosystem. These slimes are being exported in part as low-grade iron ore. The research resulted in a significant advance in developing technologies to process low-grade fine iron ores on a big scale while being cost-effective and ecologically benign.
This work reveals an innovative, cost-effective, and energy-efficient method that could be scaled up to create a technology to benefit low-grade iron ores.