Abstract

Most of the past studies examined the effects of ultrasonic treatment on the removal of phosphorus, silica and alumina minerals from iron ores. In the present work, the effect of combined microwave pretreatment and ultrasonic treatment on the efficiency of disintegration and removal of phosphorus and other gangue minerals associated with iron ores has been studied. Three different iron ore samples have varying total iron concentration (TFe) and P₂O₅ content and mineralogical textures were studied.

Microwave pretreatment generated intergranular fractures between the gangues (fluorapatite and chamosite) and oolitic hematite. These intergranular fractures improved liberation of iron ore, and accelerated ultrasonic disintegration and removal of phosphorus and gangue minerals from oolitic hematite. The results indicated that microwave pretreatment increases the efficiency of ultrasonic disintegration and removal of particles by about 20% compared to untreated sample. The results of ultrasonic treatment are quite promising. Significant increase in iron grade and reduction in phosphorus and alumina content of enriched product can be obtained. Depending on the sample texture and phosphorus distribution, about 59% phosphorus removal can be obtained.