Evaluation of reverse flotation for the trona industry

Trona (sodium sesquicarbonate), having the formula, Na2CO3.NaHCO3.2H2O is typically associated with insoluble gangue minerals such as dolomite, shale, clay and quartz. Removal of these gangue minerals may be desirable prior to dissolution in hot brine when the trona feed contains a significant amount of impurities. The development of new flotation technology for the separation of gangue minerals and production of trona concentrate has been substantiated by bench scale flotation experiments at the University of Utah. Laboratory flotation tests showed that insolubles in the feed can be successfully floated and a trona concentrate of 99% purity obtained with a recovery of 90%. In order to achieve a high separation efficiency, evaluation of reagents and formulation procedures was undertaken together with an examination of flotation chemistry conditions. In this regard, studies have been done on the effect of operating parameters such as long chain amine collectors, feed particle size, flotation percent solids and flotation time. In this paper, the results of batch flotation tests and the influence of operating variables on the flotation efficiency are discussed to demonstrate the potential of this flotation technology for the trona industry.