Fine coal beneficiation by pilot column flotation

Beneficiation of coal fines with high ash content was attempted in an operating coal preparation plant by retrofitting a 0.5 m diameter pilot plant scale flotation column in the circuit. The collector and frother dosage were optimized as 0.680 kg/t and 0.058 kg/t respectively. At these reagent conditions the operating parameters of pilot scale flotation column were also optimized. The maximum yield of the froth obtained was 67.5% at the targeted ash level of 14% from a feed of 25% ash content. This was obtained at the operating parameters of 0.85 cm/s superficial air flow velocity, 0.57 cm/s superficial feed slurry velocity and 600 mm froth height. The performance of flotation column was found to be marginally better than that of the conventional flotation cells in the washery. Also, advantages such as low operational, maintenance and energy costs and operational flexibility in the case of flotation column could lead to financial accruals over a long run