Semicommercial scale studies using flotation column and dual extraction column on iron ores of Goa, India

Goa state in India is endowed with large deposits of low-grade iron ores, geologically formed from the lower Dharwar super group of Archaean rocks. Petrological studies have revealed that silica and alumina are the main gangue minerals. where alumina exists as fine clay and adherent material interspersed in ore body and in some cases both silica and alumina are interlocked with iron ore particles. The amenability of Columnflotation and Dual Extraction Column to remove such gangue was studied by installing test units at the Greater Ferromet beneficiation plant of M/s. Sociedade De Fomento Industrial Ltd., Goa. A reverse flotation process was adopted wherein gangue minerals containing silica and alumina are floated using cationic collector. Sodium hydroxide and starch were used to regulate the slurry pH and depress the iron ore, respectively. Iron ores of different mines and their mixtures were studied using different cationic collectors. The effect of both process and column parameters on grade and recovery were established. The results clearly suggest that iron ore concentrate assaying 67% Fe and 2% Si02 and Ah03 could be obtained with a recovery of 85-90% by single stage column operation. The better performance of flotation column over Dual Extraction Column in terms of reduction of gangue was also brought out in this study.