Energy efficiency analysis of microwave treatment in rocks: from mine-to-mill operations

Abstract

As one of the most energy-intensive industries, mining faces challenges related to energy inefficiency, safety, and sustainability. These challenges prompt exploration of alternative methods, among which microwave-assisted mining stands out as significant. While existing research suggests the potential benefits of microwave treatment in mining, there remains a lack of comprehensive understanding regarding its field application. This study aims to address two key gaps in current knowledge: firstly, by examining the holistic impact of microwave treatment across the entire mine-to-mill process rather than focusing solely on individual operations, and secondly, by evaluating the energy efficiency of applying microwave treatment in the field, considering the energy required for microwave irradiation as a design factor. A novel methodology is introduced to capture the effect of microwave treatment in one operation on the subsequent ones, using a comprehensive set of experiments encompassing microwave treatment, calorimetric measurement, uniaxial compressive strength, rock cutting, and crushing tests. The results reveal that using microwave treatment in one operation has significant implications on subsequent ones, leading to an exponential increase in energy efficiency, which can be more than ten folds in some cases. Additionally, utilizing the energy efficiency-based approach, the achieved improvements are discussed per unit of input microwave energy, shedding new light on established concepts such as the effect of power and exposure time on the efficiency of microwave treatment. This study contributes to a deeper understanding of microwave treatment as a viable rock pre-conditioning method, aiming to lead the industry toward more sustainable mining practices.