COAL MACERAL SEPARATION USING COLUMN FLOTATION

Recent studies have found that coal macerals have properties which may allow their use as high-valued products. A conceptual approach for th e production of individual maceral concentrates utilizing column flota tion is presented in this publication. Before maceral separation, the coal was ground to the particle size corresponding to near complete li beration of the macerals, which was approximately 4 mu m for an Illino is No. 6 seam coal. The production of maceral concentrates using flota tion was based on the differences in the flotation rates among the var ious macerals, which was manipulated by adjustment of the medium pH. A n increase in pH from 8 to 11 resulted in an order of magnitude reduct ion in the flotation rate of the liptinite maceral group while the cor responding reduction for the inertinite group was about 50%. On the ot her hand, the kinetic rate for the vitrinite group remained unchanged. 4, using pH control and column flotation, the inertinite content was increased from 7.5% to 50%. Although the upgrading of the other two ma ceral groups was not as significant, it was evident that the success o f the maceral enrichment for a given coal is dependent on the maceral liberation characteristics and the magnitude of the flotation kinetic rate differences among the macerals.