The effect of reagents and reagent mixtures on froth flotation of coal fines

Reagent usage and type of reagent are important factors in froth flotation. The recovery and purity of the final product obtained depend on various parameters such as the type and the amount of reagent, the nature and the particle size of solids, the adsorption of reagent on solid particle surface. The froth flotation tests of bituminous coal fines were carried out using only one of three non-ionic reagents; Triton x-100, Brij-35, methyl isobuthyl carbinol (MIBC) and sodium dodecyl sulfate (SDS), and the mixture of Triton x-100 or Brij-35 with MIBC in various ratios. The froth flotation performance was changed significantly according to addition of the reagent or reagent mixtures. The highest recoveries (>90%) were achieved in the presence of conventional reagents, MIBC or SDS. However, the ash rejection values were lower in the use of the same reagents. The ash rejection was considerably improved by using the mixture of reagents. A strong relationship was observed between the solid fraction in the concentrate and the type and amount of the reagent or the reagent mixture. The combustible solid recovery and the ash rejection strongly depend on the finer particle fraction in the feed. (C) 2003 Elsevier Science B.V. All rights reserved.