Fixed Crushing and Screening Plant refers to a permanently constructed mechanical plant designed to crush big rock fragments into small and evenly sized particles at the same time sorting through them using vibrating screens. Energy efficiency, in this case, implies improving the efficiency of the relationship between the proportion of rock fragments that have been properly crushed against the amount of electricity used. The crushing and grinding processes demand high amounts of energy making it essential to improve efficiency (Adewuyi et al., 2020).
It is important to emphasize the significance of energy efficiency for plants consuming over 5 MW. For a plant of such magnitude, grinding and crushing processes can account for 50%-70% of the total energy cost (Adewuyi et al., 2020). Hence, the inefficiency of energy use in 5 MW plants will mean high costs and increased carbon emissions.
Efficiency evaluation starts with setting accurate values of the consumed power measured in kWh/ton of processed materials. Energy audit is conducted to measure electrical demand of the crushers based on the actual output. Modern evaluations rely on computational models and neural networks to replicate the comminution circuit, which makes it possible to detect energy losses during classification process (Moraga et al., 2024).
The way to increase efficiency requires efforts from the previous process, starting with rock fragmentation. The mine-to-mill strategy will allow one to ensure that rocks blasted are of an optimal size, thus minimizing the effort needed for mechanical processing. The employment of ore treatment methods helps to structure minerals so that less electricity will be needed for further mechanical processing (Adewuyi et al., 2020).
Investment in the modernization of process equipment is another efficient way of optimization. Substituting the standard crushing circuits by High-Pressure Grinding Rolls (HPGR) results in increased energy efficiency since HPGR causes micro-cracking of the ore and thus allows decreasing energy expenditures during subsequent milling (Nghipulile et al., 2023). In combination with Variable Frequency Drives, the 5 MW load can respond to production needs flexibly.
Thus, increasing the energy efficiency of a large, fixed crushing and screening plant requires an approach based on data analysis. Through the benchmarking of energy metrics and introduction of modern solutions, including the development of fragmentation methods and use of innovative equipment like HPGRs, it is possible to lower energy usage considerably.
References
Adewuyi, S. O., Ahmed, H. A. M., & Ahmed, H. M. A. (2020). Methods of ore pretreatment for comminution energy reduction. Minerals, 10(5), 423. https://doi.org/10.3390/min10050423
Moraga, C., Astudillo, C. A., Estay, R., & Maranek, A. (2024). Enhancing comminution process modeling in mineral processing: A conjoint analysis approach for implementing neural networks with limited data. Mining, 4(4), 966–982. https://doi.org/10.3390/mining4040054
Nghipulile, T., Nkwanyana, S., & Lameck, N. (2023). The effect of HPGR and conventional crushing on the extent of micro-cracks, milling energy requirements and the degree of liberation: A case study of UG2 platinum ore. Minerals, 13(10), 1309. https://doi.org/10.3390/min13101309
