The behaviour of mineral matter in fine coal flotation using saline water

Abstract

In this study the behaviour of mineral matter in the flotation of a fine coal sample using saline water was investigated. For a comparison, de-ionised water was tested in parallel. It was found that saline water increased the recovery of mineral matter while increasing the combustible recovery. By calculating the degree of entrainment in the flotation of the coal sample and also the ash after combustion, coupled with the froth image analysis and rheology measurements of froth and pulp suspensions, the entrainment and entrapment of mineral matter in coal flotation were examined. Compared to de-ionised water, saline water increased the entrainment across the size range and the increase in entrainment was more pronounced for particles smaller than 38μm. However, entrapment played a more important role in recovering mineral matter smaller than 38μm in coal flotation using both de-ionised and saline water. Saline water significantly increased the entrapment through enhancing the aggregation of coal particles.