ABSTRACT

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 k₁) and Arrheniusan-type (ln k₁ vs ξ) plots.

摘要

研究了煤颗粒的 Zeta 电位和浮选动力学以及天然疏水煤长时间分级浮选后的最大回收率，两者均作为 pH 值的函数。^{建立了浮选}一级速率常数与zeta电位以及最大采收率和zeta电位之间的经验关系。由于分馏浮选具有与化学反应相似的特征，因此发现了最大回收率与zeta电位之间以及速率常数与zeta电位之间的热力学关系。确定第¹级速率常数取决于两个常数：浮选平衡常数和表面电位活性系数。它还取决于两个变量：表面电势（近似于 zeta 电势）和作为表面电势函数的粒子-气泡聚集体（小泡）分解的速率常数。确定了浮选平衡常数、表面电位活性系数和逆过程速率常数的值。这些参数（特别是浮选常数和表面电位活性系数）可用于比较不同的浮选系统。也可用于比较目的的是动力学热力学极限（R _max vs k ₁）和 Arrheniusan 型（lnk ₁ vs ξ ) 图。