Grinding Behaviour of Microwave-Irradiated Mining Waste

Abstract

The combined microwave-assisted sorting and microwave-assisted comminution of minerals has been proposed to reduce the huge grinding energy consumption in mineral processing. However, gangue minerals would be discarded after the sorting process despite the microwave energy absorbed during their treatment. Therefore, this paper investigates the effect of microwave pretreatment on the Bond work index (BWI) of quartz and calcite samples, as they represent the dominant gangues in many ores and are key inputs in the cement industry, which requires intensive grinding. The samples were characterized using a scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX), and Fourier transform infrared (FTIR) and X-ray diffraction (XRD) methods. The BWIs of the two samples were determined before and after the microwave treatment (2.45 GHz, 1.7 kW) at 2, 4 and 6 minutes. SEM image analyses of the untreated and microwave-treated samples were performed using ImageJ software. The results showed that after 4 minutes of radiation treatment, the BWI of the studied quartz was reduced by 13.83%, while that of the calcite increased by 15.59%. The results of the SEM image analysis indicated that the quartz developed more cracks than the calcite under the same microwave treatment conditions. Based on these findings, microwave pretreatment is suitable to reduce the grinding energy of the studied quartz, but offers no energy-saving benefit to the studied calcite.

Characterization of Microschist Rocks under High Temperature at Najran Area of Saudi Arabia

“…The obtained XRD peaks were matched with built-in standard mineral phases XRD-patterns in "PowderX" and "Match!" softwares, and also compared with published work [41,48,50,51]. The findings show that the studied microschist consists of quartz, albite, clinochlore, biotite, muscovite, epidote, pyrite, zoisite, rutile, and magnesite (Figure 12 and Table 2).…”

“…The SEM image of each sample was taken at different magnifications to observe the specimen morphology. The XRD spectra of the representative powder specimens were obtained in a continuous mode at a scattering angle 2θ between 5 • and 90 • with a increment of 0.05 • using an X-ray diffractometer (Regaku, Ultima 1V, Japan; 40 mA, 40 kV, Cu kα radiation) [41,42]. The peak intensities of the XRD spectra were matched with the standard spectra using "PowderX" software (National Lab.…”

“…For each SEM-EDX characterization, a representative noncoated powder sample was fixed on the stub using carbon tape and then put into an SEM (JSM-7600F, Tokyo, Japan) sample chamber where the representative specimen area was selected after the electron beam illuminated the sample. The average constituent elements were then recorded by the EDX spectrometer (Nicolet iS50 FT-IR, Thermo Fisher Scientific, 168 3rd Ave, Waltham, MA 02451, USA) using five iterated values [41]. The SEM image of each sample was taken at different magnifications to observe the specimen morphology.…”

Eco-Sustainable Recycling of Cement Kiln Dust (CKD) and Copper Tailings (CT) in the Cemented Paste Backfill

“…The XRD pattern of the examined samples was scanned in a continuous mode with a 4 • /min scanning speed and (2θ) 10 • to 80 • angular range. Moreover, we utilized the cards of the International Centre for Diffraction Data (ICDD, Campus Blvd, Newton Square, PA, USA) for diffraction peak matching and then established the samples mineral phases [77,78].…”

Sustainable utilization of cement kiln dust and GGBS in the development of eco-friendly concrete composite

“…The requirement of concrete exceeds day by day in developing and developed countries. In the production of concrete, cement is an important ingredient which gives strength properties to the concrete [1][2][3][4][5][6][7]. For 1 tonne of cement production, nearly 1.85-tontons of limestone is utilized which tends to lack of resource availability.…”