A parametric study of column flotation for fine coal cleaning

Recovery of fine coal is becoming an important and integral part of coal cleaning plants. The froth flotation technique is widely used for recovery of fine coals: however, the technique becomes inefficient when excessive amounts of ultra-fine clay material is present. The counter-current column addresses this problem by providing a stream of wash water to remove fine clays from the froth. The experimental results reported herein examine the effect of column operational parameters (feed rate, frother concentration, airfiow. column height, pulp density and wash water) on cleaning of fine coal. The study was conducted using the Plackctt-Burman experimental design followed by a 2⁳ factorial design. The study identifies frother concentration, column height and airflow as the most significant parameters and enabled characterization of the magnitude and interaction of the effects. In general, for the same amount of frother concentration column flotation provided a lower ash clean coal product compared to the conventional flotation. The paper describes the test procedure, results and conclusions obtained.