Modified flotation rate constant and selectivity index

Kinetic models are often used to analyze batch flotation results. Two parameters, R∞ (ultimate recovery) and k (first-order rate constant) are obtained from the model fit to an experimental recovery-time curve. Comparison of either R∞ or k obtained under different conditions can often be misleading. In order to overcome this problem, a modified flotation rate constant, Km, is introduced. It is defined as the product of R∞ and k, which is the slope of the tangent of the recovery-time curve at zero flotation time: KM = R∞·K uently, a parameter measuring the degree of selectivity or a selectivity index can be introduced among the different minerals presented in a flotation system. Two examples of a typical nickel sulphide ore flotation are given to illustrate the calculation of the modified flotation rate constant and selectivity index. The modified rate constant and selectivity index are useful tools for comparative evaluations of various operating parameters affecting flotation processes.