An experimental investigation on column flotation circuit configuration

The integration of flotation columns into existing flotation circuits of conventional mechanical cells is becoming increasingly common in industry. Nevertheless, the study of column circuit configuration is scarce and problems relating to the selection of the appropriate circuit have not been addressed. Various column circuits for flotation of coal fines have been experimentally examined and theoretically analyzed in the present study to reveal the effect of circuit configuration on the overall circuit performance evaluated using separation efficiency and separation curves. The flotation circuits examined in this study included single-stage (SS), rougher-scavenger (RS), rougher-cleaner (RC), rougher-scavenger-scavenger cleaner (RSSC), roogher-scavenger-cleaner (RSC), and rougher-cleaner-recleaner (RCRC). The flotation tests were carried out with the Pittsburgh No. 8, Illinois No. 6 and Upper Freeport coal samples that were precleaned using conventional flotation. It has been demonstrated that the overall separation efficiency of the column flotation system was rather insensitive to circuit arrangements due to the unique characteristics of the unit flotation column distinguished from the conventional flotation cell. The flotation separation efficiency changed with ash or sulfur rejection and the Pittsburgh No. 8 and Illinois No. 6 coal samples showed a stronger dependence of separation efficiency on ash rejection than the Upper Freeport coal sample. The experimental results were shown to be in good agreement with theoretical circuit analysis conclusions. (C) 2000 Elsevier Science B.V. All rights reserved.