Experimental and computer studies of the dynamic behaviour of an industrial grinding circuit

Abstract

The technique used to collect data on the dynamic behaviour of a high capacity multi-stage industrial grinding circuit is described. These data include the response of the circuit to step changes and sinusoidal changes in ore feedrate and water addition. The response to water addition was tested at several points in the circuit.The data have been used to evaluate existing mathematical models of the grinding and classification processes. Both steady state and dynamic models have been examined.A system of computer programs for the dynamic simulation of grinding circuits on a large PDP 10 digital computer has been developed. The results of dynamic simulation of a closed circuit have been compared with the results obtained from plant test work and reasonable agreement has been obtained.The dynamic and steady state closed circuit models have been adapted successfully for simulation on a small POP 8/1 process control computer. This work has shown 1. that small computers may be used successfully far simulation studies, and 2. that the closed circuit model may be applied as an on-line model in a small computer control system.A method has been developed in which the closed circuit model has been utilised to detect changes in ore hardness in an on-line configuration.Several data analysis techniques for use on the computers have been developed and tested. An efficient computing technique for the utilisation of the generalised least squares algorithm has been implemented. This technique has been applied to the calculation of mass balances and the calibration on industrial plant instruments.