Prediction of Circulation Load of Side-Flanged High-Pressure Grinding Rolls Closed-Circuit Crushing

To enhance the performance of the combined high-pressure grinding roller (HPGR) and tower mill (TM) process for −1 mm particle size, this study addresses the key technical challenges of insufficient material quantity (<100 kg) and complex experimental procedures in HPGR closed-circuit crushing tests by proposing a novel circulating load prediction method based on the principle of mass balance and first-order crushing kinetics. Using a side-flanged HPGR WGM 6020 installation, systematic −1 mm HPGR closed-circuit crushing tests were conducted on seven different ore samples under three specific pressing forces, with detailed characterization of the dynamic variations in product size distribution, specific energy consumption, and circulating load during each cycle. The results demonstrate that within the specific pressing force range of 3.5 N/mm2 to 4.5 N/mm2 when the crushing process reaches equilibrium, the circulating load stabilizes between 100% and 200%, while the specific energy consumption is maintained within 1–2.5 kWh/t. Notably, at the specific pressing force of 4.5 N/mm2, both the circulating load and specific energy consumption display significant improvements.