Abstract
In today's world where global climate change challenges and energy crises are increasing, the contribution of comminution to the total world electrical energy consumption is about 3%, and a considerable amount of energy input to the comminution circuit is absorbed by the grinding process. As presented in numerous literature sources, HPGRs have successfully been proven in the industry to reduce operating costs compared to other alternatives in full-scale processing plants despite their higher initial costs. Also, due to their lower direct energy consumption and downstream energy savings, they create grinding and mineral recovery. The HPGR process is a more efficient technology due to the high-pressure, counter-rotating rolls or tires that create excessive stresses and micro-cracks in the material crush zone. It is explicit that the use of HPGR is a cost-effective and energy-efficient alternative to the processing of certain types of mineral ores such as iron, gold, copper, and diamond. So what exactly makes the HPGR process energy efficient on a circuit basis? Do ore amenability, operating conditions, and employed circuits significantly impact HPGR energy consumption and overall efficiency? This paper aims to provide a comprehensive review of why HPGR is more energy-efficient than conventional grinding mills and explore its advantages and disadvantages. It also presents the results from some key investigations and an integral evaluation focused on the energy efficiency impact of HPGR, considering upstream ore characteristics, operational factors, liberation processes, and downstream operations. Most studies showed that operating conditions such as pressure, throughput, and grinding force all relate to the HPGR's energy consumption and the efficiency of the process. Also, the ore amenability to HPGR is critical in designing an optimal operation and must be first tested. Also, the circuit's energy consumption is based on the different HPGR configurations, such as open or closed circuits as well as utilization of screens or air classifiers. HPGRs are more energy-efficient than conventional tumbling mills and decrease comminution costs by 23-25 %, and the total energy calculated by the HPGR circuit reduces emission criteria such as environmental impact or carbon footprint by 26-39 %. This review article can be a resource that provides literature information and develops a different point of view for those who want to read and learn comparatively before doing a study on this subject.