Operational parameters affecting the vertical roller mill performance

Vertical roller mills (VRM) have found applications mostly in cement grinding operations where they were used in raw meal and finish grinding stages and in power plants for coal grinding. The mill combines crushing, grinding, classification and if necessary drying operations in one unit and enables to decrease number of equipment in grinding circuits. Sustainable operations and proven benefits of the technology in cement grinding applications attracted interests of the mineral industry. Within the scope of the study, ore grinding performance of the VRM was investigated via a mobile grinding plant and relationships between operational parameters were identified. In this context, gold ore was ground under different process conditions. The samples collected after the test works and size distributions were determined. As a result of the study, effects of operational parameters such as working pressure, and classifier rotor speed on product mass flow and product size were investigated. In addition, correlations of specific energy consumption of the grinding-classifying circuit with product rate and product size are presented. The aim was to develop a VRM performance prediction model that is based on input data from characterization combined with the knowledge of the interaction of the single grinding parameters.