Performance evaluation of the VSK separator for treating mineral fines

Abstract

The separation process is an integral part of many industrial operations. Most of the present-day plants incorporate dry separation units compared to wet separators, due to scarcity of water and process needs. The VSK separator is a dynamic air classifier widely used in closed circuit with High-Pressure Grinding Rolls (HPGR). The HPGR-VSK separator circuit reduces the grinding energy consumption considerably compared to the conventional ball mill-classifier circuits. However, the fundamental principles of VSK separation and its applications in mineral classification/separation are not well reported in the literature. In the present investigation, pilot-scale experiments were carried out on VSK separator by varying feed rate, cage wheel speed, and blower speed to assess the classification and separation efficiency. The experimental results indicated that classification imparts 8.5–38.5% yield to the fines product with a d50 cut-size varying between 18 and 106 µm. Statistical analysis carried out to evaluate the separation efficiency indicated that the cage wheel speed and blower speed are having a prominent effect on the product yield, silica content, and d50 cut-size. The interaction effect between cage wheel speed and blower speed plays a vital role in product quality. The classification and separation efficiency of the unit was evaluated and discussed with respect to different operating parameters. Further, the size separation index (SSI) has been developed to quantify the separation efficiency, which is simpler than the conventional ways of assessments.