Grade-recovery Prediction of an Operating Plant Using Flotation Model and Operating Conditions

A transient flotation model for the purpose of flotation control has been proposed in this paper, which describes the operation from one steady state to other steady state when influential process variable (such as reagent addition, air flow rate, level etc.) change during operation. The proposed model assumes first order kinetics of floating species under specified process conditions. During transition, the material with rate constant Kb (before condition) and volumetric solids hold-up mh,b will start depleting in the system and a material with rate constant Ka (after condition) and volumetric solids hold-up mh,a starts building up till all the material with rate constant Kb is completely depleted. This will influence the change in the grade and recovery of the process.In order to verify the model, detailed plant campaigns were done under steady state on a lead zinc ore plant, components assays were analyzed for various streams (% Pb, % Zn and % Fe), mass balance performed. Regression relations were built from partial campaign data by relating local influential operating variables with their solid flow split, water flow split and Pb flow split. These relations were linked to flotation model to simulate the effect of operating variables on grade and recovery of the plant. The framework presented in this paper is equally applicable to phosphate mineral flotation.