Pneumatic flotation: an alternative to the conventional mechanical flotation machines?

摘要

In response to the increasing economic pressure on producers of coking coal in Germany, theRuhrkohle Bergbau AG (RBA G) opted to undertake an extensive increase of their existing flotationcapacity. Two new flotation units were built in 1996, with aim of reducing the ash content of thecoking coal by 0.7% and therefore take advantage of the higher sales prices attainable for theimproved product. The flotation units were designed according to different concepts. Whereas theoperators of the Heinrich Robert mine decided to install a conventional floatation unit with amechanical cell, at the Lohberg colliery, the existing floatation unit with Denver system cells wasextended with a two-stage pneumatic flotation system. Since commissioning of the units in 1997 testshave been carried out at the both plants, primarily to optimize the performance of the units, but alsoto establish a reliable data set enabling comparison of the different flotation techniques. Tests wereconducted on laboratory scale by the school of mines "Technische Fachhochschule Georg Agricola"in Bochum and on industrial scale at the processing plants by the RBAG and DMT Gesellschaft furForschung und Prufung mbH (DMT). Although the optimization work has not yet reached itsconclusion, the results obtained so far clearly demonstrate the success of the new concepts.