Beneficiation of Coal Fines by Aggregative Flotation

The effect of various operating parameters on the performance of the aggregative flotation process for beneficiating coal fines was investigated. The recovery of carbonaceous matter was found to be improved by high mixing intensity and by the utilization of preemulsified collector in the aggregate formation stage. The presence of salt in the flotation stage was found to enhance recovery of the aggregates and the use of a three-stage aggregative flotation technique was found to recover more than 95% of the carbonaceous matter while rejecting 94% of the liberated ash (67% of the total mineral matter). This was accomplished using 2 kg of kerosene per tonne of coal while, in contrast, conventional flotation techniques yielded a recovery of 47% at a collector dosage of 7.5 kg/t.