Briquetting Conditions for Australian Hematite-Goethite Iron Ore Fines

The effects of the operating parameters of the briquetting machine, feed moisture content and the addition of hydrated lime as a flux on the green and fired properties of briquettes produced from Australian iron ore fines were investigated to determine the best operating conditions for producing satisfactory briquettes. The results confirmed earlier work that iron ore fines can be agglomerated by briquetting to produce a feed material suitable for a blast furnace. Feed moisture was found to be a critical operating parameter while machine operating parameters had secondary effects. The density of the green briquettes was found to depend on feed moisture content with higher density briquettes being produced with lower moisture contents. The strength of the green briquettes depended on the density of the green briquette. Feed moisture contents of 7.5-8.5 wt% resulted in a high yield of whole briquettes with densities of 3.40-3.45 g/cm(3) and green strengths of 4.0-5.5 kgf. The briquettes produced could be dried rapidly, potentially giving higher productivity values for production of briquettes compared with pellets. During briquette induration the green briquettes performed well. The basicity of the briquettes and the firing temperature had the most significant effect on the product quality. For firing temperatures of 1 300-1 350 degrees C, and a basicity of 1.22, fired briquettes with good mechanical strength and reduction properties were obtained. Crush strengths ranged from 200 kgf to >450 kgf.