Optimisation of process parameters for coal flotation using statistical technique

The ash content present in coal plays an important role in determining the quality or grade of the coal for its utilization in different industries. The maximum ash content allowed for steel grade I is 15%, while steel grade II requires ash content ranging from 15% to 18%. A sample of coking coal analysing 26.32% ash was subjected to froth flotation to reduce its ash content to below 18%. Optimization of flotation process parameters such as collector, frother dosages and airflow rate, was carried out using factorial design of experiments.
It was observed that the interaction of collector and frother dosages had the most significant impact on achieving the desired ash rejection, with collector dosage also playing an important role. Optimum process parameters identified are collector dosage of 0.0348 kg/t, 0.005 kg/t frother dosage and 2 lpm airflow rate, wherein the ash content of the sample was reduced to 14.58% from 26.32%.