Effect of operational conditions on energy efficiencies of air-swept ball mill and classification circuits in cement raw material production

Abstract

Operational performance and energy efficiencies of cement raw material grinding air-swept ball mill and classification circuits were analysed and discussed in this study. Extensive sampling surveys were performed around the circuits A and B in which single compartment air-swept ball mills with dimensions of Ø3.8xL10m and Ø3.8xL10.15m respectively were closed circuited with static air classifiers. Operational results demonstrated that, specific energy savings of 48.47% in ball mill grinding can be achieved with the operational conditions in circuit-B as compared to the conditions in circuit-A. Ball mill with the same dimensions can be operated as much more energy efficient depending mainly on the feed fineness and grindability values. Mill raw material feed particle size distribution fineness and work index values were the important parameters in obtaining finer material from the mill. However, air classifier should also be operated at its optimum operating conditions in obtaining finer final product from the grinding circuit. In this context, various ways to alter the fineness and grindabilities of raw materials should be investigated so that to increase the capacity rates of air-swept ball milling circuits in raw material production line. For example; application of pre-crushers as High Pressure Grinding Rollers (HPGRs), integration of screens to the circuits, optimization of blasting conditions in the open-pit mining stage and attaining of optimum operational conditions for the air classifier. Copyright © IMCET 2019 International Mining Congress and Exhibition of Turkey. All rights reserved.