Utilization of Iron Ore Tailings for Brick Manufacture from Donimalai Mines of Karnataka, India

Abstract

Mixing iron tailings with cement, sand and sodium silicate for manufacturing bricks was studied with the objective of converting the iron ore tailing waste into value-added products. Bricks were prepared using different compositions of iron tailings with proportions of Ordinary Portland Cement, sodium silicate and sand in cuboid mould (9″ X 5″X 3″). Bricks were air dried for 24 hours, placed in oven for 115 ± 10 °C for 24 hours. Mechanical properties such as compressive strength (CS), water absorption (WA), and efflorescence were measured. The maximum CS of 8.58 N/mm² was recorded for tailing and cement ratios of 8:2. However, for making it more economical the ratio of 9:1 was considered and this compares very well with the Indian standard (IS): 3495 (Part 1) (1992) of bricks. The results also indicated that the tailing percentage in the bricks affects their mechanical properties. The WA rates of the manufactured bricks are low compared to standard fired clay bricks, and the same varies with process parameters. The low capillary pore may deter the formation of efflorescence. The process, with standardized parameters, may be commercially adapted, and large quantities of iron ore tailings may be put to use in making bricks. Thus, the process technology observed in this paper can potentially convert the huge amount of environmentally hazardous waste into value added product. Iron ore tailing may materialize as a sustainable supplement to soil's clay, use of which in brick making is restricted. The finding also usher a new area of research.