Brahmani River Pellets Ltd (BRPL), a majority owned Stemcor project, comprises a 4m tonne per annum beneficiation plant in Barbil, Odisha, and a pellet plant complex in Jajpur, Odisha, connected by a 220km underground slurry pipeline.
The beneficiation plant takes low grade iron ore fines from various local mines and refines them using grinding and magnetic separation processes. The particles are then mixed with water to form a slurry, which is pumped through an underground pipeline to the pellet plant. The underground pipeline reduces road traffic and ambient dust pollution between the beneficiation plant and the pellet plant. CO2 emissions are reduced by 91% compared to road transport and 87% compared to rail transport. Energy consumption is reduced by 97% compared to road transport and 96% compared to rail transport. The beneficiation plant takes the average iron content up from around 60% to over 65% before sending it to the pellet plant.
The pellet plant, located close to a number of steel producers, uses travelling grate technology to convert low grade fines into value-added pellets. When the slurry arrives at the pellet plant it is stored in holding tanks before being fed through pressure filters and mixed with additives. The purpose of the additives - limestone, bentonite, coke and anthracite – is to improve the physical and metallurgical properties of the pellets during processing and in final use. A disc pelletiser is then used to ball the mixture into ‘green balls’ about the size of a marble.
A roller screening mechanism removes any undersized material before the green balls enter the final stage of production, the induration furnace. The induration process uses travelling grate technology and a series of updrafts and downdrafts to dry and gradually heat the green balls to remove moisture before entering the combustion zone where they are first preheated to minimize thermal shock, then fired and ultimately cooled in various sections of the furnace. After screening out oversize and undersize pellets, the final product – which will have the required properties for charging a blast furnace and be ready to withstand handling and transportation – are transferred by conveyor to a stockpile.
Demand for pellets is set to increase in India as competing lump ore from the lower benches of seams is becoming scarcer. High grade pellets command a price premium as they offer major benefits to steel producers, reducing raw material consumption, saving energy and simplifying the furnace feed process. In addition to healthy domestic demand there is also demand from countries such as China – the nearby port of Paradip is ideal for shipping and the Indian government has made pellet exports duty free in a bid to encourage domestic value addition in the mining sector.