Improved Flotation of Oolitic Hematite Ore Based on a Novel Cationic Collector

Abstract

Oolitic hematite is one of the most refractory iron ores with complicate mineral compositions and abundant reserves in China. The hematite and limonite in the ore integrate closely with fine particles of collophanite, quartz, chamosite, calcite and chalcedony to form concentric ring structure, making the separation of the minerals extremely difficult. Since the tiny hematite crystal can not be liberated during the grinding of the ore the beneficiation can only be accomplished by recovering iron minerals aggregate with hematite as the major component. The previous research results showed that reverse flotation with fatty acid collectors could remove liberated phosphate minerals but not the quartz, chlorite and silicate minerals. This was because the gangue minerals such as quartz were contaminated by iron on the surface and there were high content of iron in some silicate minerals and high content of silicon in iron minerals, causing the floatability difference between the silicon and the iron minerals very small and thus the separation efficiency very low. Experiments were conducted to beneficiate the ore by reverse flotation with different cationic collectors. The results indicated that the flotation separation efficiency with most cationic collectors such as dodecylamine, ether amine, GE601 or GE609 was not satisfactory. However, a novel cationic collector for silicon removal, EM506 was found to be specifically selective to separate the gangue minerals from the iron ore with an increase of TFe grade from 49% to more than 58% and a recovery of TFe greater than 96%, which provided a promising approach for the beneficiation of the refractory oolitic hematite ore.