Investigating the benefits of replacing hydrocyclones with high-frequency fine screens in closed grinding circuit by simulation

Screens, which provide better separation efficiencies compared to hydrocyclones, have been attracted the attention of minerals industry for many years. However, low capacity in fine screening applications has limited the use of screens to classify the ball mill product in wet grinding circuits. In recent years, the separation efficiency of fine particles in a small footprint has been largely increased by the advances in high-frequency screening technology, thus increasing the use of screens to close fine wet grinding circuits. The potential of high-frequency fine screens to improve overall circuit performance was evaluated in this paper using lead-zinc ore grinding data. Data come from circuits at the lead-zinc mine in Turkey where both high-frequency screens and hydrocyclones are used to close grinding circuits. The ball mill-hydrocyclone circuit and the ball mill-screen circuit were sampled in order to measure and compare the performance of the circuits. The ball mills are different in design. Therefore, simulation studies were carried out to eliminate the differences in factors affecting the performance of the circuits such as milling conditions. Data indicated that using high-frequency screens in place of hydrocyclones in grinding circuit improves throughput by reducing the circulating load. Lower by-pass and sharper separation provided by high-frequency screens are the major factors affecting the capacity of the circuit and the results showed that 13% more throughput is achieved with 15% less grinding energy when hydrocyclones are replaced by high-frequency fine screens.