An operator friendly performance index for frother selection and optimization in coal flotation

Abstract

The demand-supply gap for indigenous met coal of acceptable quality in India has reached such a level that coal blends in integrated steel plants usually have a ratio of 70 to 30 between the imported and domestic. Met coal constitutes nearly 30% of steel production cost in India. Met coal wash plants in India are hard pressed to reduce the washing cost. Fines circuit capacity generally had been 10-25% of the plant throughput. Reagents appear to constitute a minimum 45% of the coal flotation and associated dewatering cost in India. Contribution of frother alone to total reagent cost is around 30%. Selection of collector in coal flotation is usually between diesel oil and kerosene. Plant operators however face difficulty in quick selection of a frother from among those supplied by different manufacturers. There can possibly be no universal frother which would perform best irrespective of fluctuation in feed characteristics, typical for met coal wash plants in India. Therefore, an index has been proposed which takes into account all major performance parameters such as yield, misplacement, ash, selectivity, flotation rate and reagent cost. This index, convenient for plant operators, evaluates frother performance through the performance evaluation of the flotation process itself. (13 refs.)