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Evaluation of kinetics and thermodynamics of a naturally hydrophobic coal flotation in the presence of frother and regulated with pH

Year: 2022

Journal: Int. J. Coal Prep. Util., Volume 42, 37561, page 3415–3429

Authors: Canieren, Omer; Karaguzel, Cengiz; Drzymala, Jan; Sahbaz, Oktay

Keywords: Rate constant; maximum recovery; flotation equilibrium constant; surface electrical potential; zeta potential; contact angle

Zeta potential of coal particles and kinetics of flotation along with the maximum recovery after a long time of fractionated flotation of naturally hydrophobic coals, both as a function of pH, were investigated. Empirical relations between the 1(st) order rate constant of flotation and zeta potential as well as the maximum recovery and zeta potential were established. Since fractionated flotation has features similar to chemical reactions, thermodynamic relations between maximum recovery and zeta potential as well as between rate constant and zeta potential were found. It was determined that the 1(st) order rate constant depends on two constants: flotation equilibrium constant and activity coefficient of surface electrical potential. It also depends on two variables: surface electrical potential (approximated with zeta potential) and the rate constant of the particle-bubble aggregate (flotulas) disintegration being a function of surface electrical potential. The values of the flotation equilibrium constant, activity coefficient of surface electrical potential and reverse process rate constant were determined. These parameters (especially flotation constant and activity coefficient of surface electrical potential) can be used for comparison of different flotation systems. Also useful for comparison purpose are kinetico-thermodynamic limits (R-max vs k(1)) and Arrheniusan-type (ln k(1) vs xi) plots.