Optimization of coal flotation using statistical technique

The flotation studies of non-coking coal fines containing 37.7% ash were carried out. The variables studied were pH, collector, frother, modifier (sodium silicate) and coal size. Experiments were carried out using 25 full factorial design. The main and interaction effects on recovery and grade were evaluated using Yatesʹ analysis. The optimum flotation condition was found by the method of steepest ascent. A product with 72.62% combustibles (i.e. 25.38% ash) at 88.03% recovery was obtained at pH 7.5, diesel oil 0.42 g/kg, MIBC 0.09 g/kg, sodium silicate 0.02 g/kg and coal size −0.6 mm at optimum conditions.