1. BHP Billiton Newcastle Technology Centre, NSW 2287, Australia;2. BHP Billiton China, Shanghai 200020, China;3. Technology Centre of Baoshan Iron and Steel Co., Ltd., Shanghai 201900, China; 4. Raw Material Management Center, Manufacturing Management Depart. of Baosteel Branch, Shanghai 201900, China
Abstract:The coke combustion process in iron ore sintering is dependent on the coke size. Therefore pilotscale sintering tests with blends containing different coke size distributions were carried out to investigate the effect of coke size (the ore blend contained 10% MAC marra mamba fines). It was found that increasing the coke mean size by reducing the percentage of the finer coke fractions (0.25 mm and -1 mm) led to a significant improvement in flame front speed, yield and productivity and a lower coke rate. This was due to more efficient combustion of larger coke particles in a granulated mix and also to better granulation and therefore higher green feed permeability and sintering permeability. The improved energy utilisation also produced sinter with a lower RDI (reduction degradation index). Sinter mineralogical analysis found that even though tests with coarser coke required lower fuel rates, the product sinters contained more magnetite phase and less secondary hematite.