Simulation of layout rearrangement in the grinding/classification process for increasing throughput of industrial gold ore plant

Abstract

In this study, a simulation of layout rearrangement in grinding/classification process was conducted to increase the throughput of an industrial plant processing 5.9 t/h of gold ore in Jeollanamdo province, Korea. The layout was rearranged to maintain the final product particle size while restoring the loss of throughput that has resulted from recent developments in mines. The process is composed of two-stage circuit, the first stage is an open circuit of the first ball mill and spiral classifier, and the second stage is a closed circuit of the second ball mill and hydrocyclone. Particle size distributions of each streams were predicted through simulation, using the population balance (PBM), Stokes' and Plitt's models for the ball mill, spiral classifier, and hydrocyclone, respectively. Lab-scale parameters for PBM were obtained by conducting batch grinding tests. The obtained lab-scale parameters were scaled-up using an empirical scale-up equation based on the industrial plant conditions. Using the obtained particle size distributions, the reduction ratio based on the 80% passing size was calculated to be 80.5 for the first ball mill, while it was only 1.19 for the second ball mill. To solve the process imbalance problem, a layout rearrangement that involves the switching of the first and second ball mills in the process was proposed. The final product was finer, with the 50% passing size reducing from 35 mu m to 31 mu m. The throughput of the industrial plant can therefore be increased by approximately 36% to 8 t/h. This study provides the guideline of the methodology which can help in adapting the simulation of layout rearrangement in the grinding/classification process for an industrial plant.