Effect of air velocity, pH and frother concentration on vitrinite recovery using column flotation

Abstract

Coal macerals can be separated using flotation process by taking advantage of differences in theirsurface properties. In this work, the effect of pH, air velocity (Jg) and frother concentration (FC) on the vitrinite separation of two coal samples from Colombia, Cerrejón and Jagua was studied. The experimental runs were carried out by flotation column at pH ranging from 4 to 10, FC from 2 to 6 ml of frother/kg of coal and Jg from 0.7 to 2.1 cm/s Jg. Results showed that both coals exhibited vitrinite recoveries above 60% at pH 5, Jg 1 cm/s and FC of 3 ml/kg of coal. For Cerrejón coal, the highest vitrinite recovery (63.55%) was obtained at pH 7, Jg 0.7 cm/s and FC of 4 ml de frother/kg of coal, whereas for Jagua coal, the highest vitrinite recovery (69.80%) was obtained at pH 4, Jg 1.4 cm/s, and 4 ml of frother/kg of coal respectively. It was also noted that both coals exhibited the highest value of vitrinite recovery at acid conditions compared with those obtained using basic conditions.