An investigation into a lower temperature and low cost Direct Reduction process for iron-making

The blast furnace process for the reduction of iron ore to pig iron faces problems such as emission of air pollutants, high investment cost and the current major problem of decreasing supplies of coke. Coke is used in large quantities to promote a combination of direct and indirect reduction within the furnace. Due to the lack of good coking coal within South Africa, and dwindling supplies worldwide, new iron-making processes, are being developed using coal and/or natural gas to replace coke as the reductant. The new processes allow efficient use of carbon, fed in the form of coal pellets (coal-based processes) or natural gas (gas-based processes), as the reducing agent. Presently, most coal-based processes Use an excess of coal, up to 500 % stoichoimetric addition, and are run at temperatures up to ±1200°C, although reduction tends to proceed at ±850°C. This project developed a low temperature process using mixed pellets of fine waste iron oxide and fine domestic coal with a natural carbonaceous binder (a by-product from local pulping industry). Reduction tests performed on composite pellets in a tube furnace and thermobalanc