Derivation of methodology capable of identifying suitable collectors for coal flotation by using surface dependant techniques

Abstract

The aim of the study was to develop an understanding of fine coal flotation emphasizing developing methodology capable of selecting the optimum flotation reagent. A secondary aim was to use the experimental data in a statistical program to validate the findings and investigate correlations between flotation performance and coal characteristics. The predictions that were made from the coal characterisation results were confirmed. Oleic acid, iso-decanol and dodecene resulted in the best flotation performance on the coal samples that were evaluated. This is in agreement with previous research findings, that oleic acid is a good collector for coal and that branched hydrocarbons also increase flotation yields. The ability of unsaturated hydrocarbons to increase flotation yield was also confirmed. The study included 5 coal samples from different collieries - Twistdraai (Highveld seam 3 and 4), Waterberg (Zone 10 -11), Syferfontein seam 5 upper (Highveld) and Witbank seam 2 and seam 4. Twistdraai, Waterberg and Syferfontein seam 5 upper were all found to be vitrinite rich coals. The Witbank coals are both more inertinite rich. The feed ash contents determined for the flotation feed samples were 28.8% for Twistdraai coal, 13.9% for Syferfontein seam 5 upper, 28.8% for Waterberg coal, 16.1% for Witbank seam 2 coal and 33.8% for Witbank seam 4 coal. The coal characterisation study included petrographic analysis, proximate analysis, float-sink analysis, oxygen-containing functional groups, surface extraction, flotation release analysis and contact angle measurements.