Thermally assisted liberation of high phosphorus oolitic iron ore: A comparison between microwave and conventional furnaces

This paper aims to investigate the effects of microwave, and conventional heating pretreatment on the liberation of iron bearing minerals from high phosphorus oolitic iron ore, specifically iron ore from the Aswan region of Egypt. These effects were analyzed by examining intergranular fractures generated between the oolitic/matrix and in the oolitic layers. Grindability and energy consumption were also measured after both microwave and conventional heating pretreatments. Scanning electron microscope (SEM) photomicrographs indicated that intergranular fractures are formed between the gangues (fluoroapatite and chamosite) and hematite after microwave treatment (resulting in improved liberation of the iron ore) while only a small number of micro-cracks were observed between the oolitic/matrix and in the oolitic layers after conventional heating of iron ore. Grindability tests indicated that microwave treated iron ore could be more easily ground compared with iron ore treated in a conventional furnace. This improved grindability is attributable to the large amount of intergranular fractures which are formed on the oolitic iron ore after treatment with microwave radiation. Energy consumption measurements also revealed that microwave treatment consumes much smaller quantities of energy compared with conventional heating ovens. (C) 2014 Elsevier B.V. All rights reserved.