Coal Preparation » Process Control
This study is concerned with finding a new technique for the determination of a frother's effectiveness in the flotation of coal. A small bench top unit was investigated in an attempt to minimise labour, capital and time costs associated with testing frother effectiveness.
A small flotation cell with column attached, with less than three litres of feed solution required, was constructed. The height of the froth column could be varied with extension pieces to give six different column heights. Coal was floated in the column, using sparged air, and the product mass flow rate was measured for each height, and plotted against froth depth. The flow rate was extrapolated to zero height, to obtain values for mo, the mass flow rate of froth at zero froth depth.
In a system of approximately 4% coal and 500 g/ton diesel oil, three different frothers were studied: MIBC, Teric 407 and Dowfroth 250. Three different concentrations of these frothers were tested: 20 ppm, 25 ppm and 30 ppm. Values of the product flow rate at zero height, mo were found for the three concentrations of the three frothers.
Using the test it was found possible to discriminate between the performance of the three frothers, at the three levels of concentration. The test shows promise as a means of characterising the performance of the frothers. However, further work is needed to link the results of the laboratory tests with the performance of the frother in a larger flotation cell.