THE RELATIONSHIP BETWEEN THE FLOATABILITY OF LOW-RANK COAL AND ITS ADHESION TO AIR BUBBLES IN AQUEOUS DIACETONE ALCOHOL-SOLUTIONS

Aggregative flotation tests of coal rank 31.1 for particle sizes —0.15, -0.25, -0.385, and -0.5 mm at a constant collector dosage (100 kg/t) and at frother reagent dosages varying from 20 to 50 kg/t were carried out. Calculations of the adhesion of aqueous diacetone alcohol (frother reagent) solutions to a coal surface precoated with n-alkanes were also made on the basis of contact angle values asured earlier. The coal flotation results obtained were correlated with the contact angle, work of adhesion, and detachment force of an air bubble from the coal surface. On the basis of the results it was determined that an increase of diacetone alcohol concentration causes an increase of coal recovery and concentrate yield, especially for fine-grained flotation feeds, and the quality of the concentrates decreased simultaneously. It was also found that there is a relationship between the yield of concentrates and the contact angle, the detachment force, and the work of adhesion. The maximal detachment force corresponded to the maximal concentrate yield and the minimal work of adhesion. © 1990, Taylor & Francis Group, LLC. All rights reserved.