A comparative study on flotation of coal using eco-friendly single reagent and conventional dual-reagent system

The continuous depletion of low ash coals and raising demand of clean coal due to increase in consumption in various sectors such as iron and steel industries, the washing of high ash coal has become inevitable. Froth flotation is one of the beneficiation methods in coal washing that exploits the surface hydrophobicity difference between coal, that is naturally hydrophobic, and its associated ash forming minerals that are commonly hydrophilic in nature. This natural hydrophobicity of coal surface acts as an advantage in reducing the ash content of coal by flotation as it is a surface-phenomenon based separation technique. In this study, a coking coal with 25.75% ash was subjected to beneficiation by flotation at two different size fractions of 100% passing 0.5mm and 0.25mm. The flotation studies on these two size fractions was studied using commercially used collector and frother. A newly developed reagent, Collector AB, synthesized from natural percussor was used as as coal collector. The collectors AB is environmentally non-hazardous and safe to use in coal washeries unlike most commercial coal collectors and hydrocarbon oils that are being used at large scale. The process optimization of the flotation reagents was studied at two different size fractions of the coal sample and the flotation efficacy was found to be comparable. Hence, this developed reagent would be alternative to commercially available flotation reagents and other hydrocarbon oils presently being used for coal flotation.