Investigation of Relationship Between Residence Time Distribution and Size Distribution of Solid Particles in Tank Leaching Modelling

While many studies have confirmed the effect of particle size distribution on the residence time in a reactor, the most employed models of continuous tank leaching process consider the residence time and particle size distributions as independent variables. In minerals processing field, no systematic study has been conducted on this issue yet. In this research, the relationship between the particles size and their residence time in a mixing tank has been studied. An empirical method for the determination of the residence time distribution function based on the inflow particles size distribution has been proposed. The relationship between the average size of one size fraction of particles and its residence time was obtained by mean residence time and parameter  (an empirical coefficient). Results showed that increasing the particle sizes resulted in a 50% increase in the mean residence time while  decreased from 0.95 to 0.3. Using the evaluated values of  the residence time distribution function of the inflow stream was determined. Including this function in the segregated flow model, the effect of the variations of the  value on the leaching performance was evaluated. Results showed that smaller values of  resulted in higher conversion value.