Dual-energy gamma-ray technique for quantitative measurement of coal ash in the Shahroud mine, Iran
Introduction
Knowledge of the coal quality and coal ash percent is vital for applications of coals for metallurgical purposes. The coals in Iran, which are generally used for metallurgical purposes, are high-ash types. Conventional methods (combustion methods) for the measurement of coal ash are time consuming. From 1980, nuclear (isotopic) techniques for the on-line measurement of coal ash have been developed in many countries. This technique has also been developed in Iran into a valuable tool for coal ash measurement in coal mines Abedinzadeh et al., 1993, Abedinzadeh et al., 1995. Nuclear technique devices were designed by the Atomic Energy Organization of Iran and were used for the first time in this project for coal ash measurement. We investigated the utility of this technique for measurement of coal ash in different coal mines in Iran. In particular, this paper reviews applications of conventional and nuclear (isotopic) techniques in different coal types of the Shahroud mine, one of the significant economic coal resources in the northeast part of Iran.
In this study, the coal ash from Shahroud coal mine was measured using this nuclear technique. We also tested this method on the samples from Zirab coal mine (Esmaeilnia and Ghafourian, 2000).
Section snippets
Structure of dual-energy gamma-ray technique
There are several nuclear (isotopic) techniques for measuring the ash content of coal. These techniques include the gamma–gamma technique, gamma-ray neutron-activation analysis technique, the natural gamma-ray activity technique, and the dual-energy gamma-ray transmission technique. The structure of the constructed nuclear (isotopic) technique device in Iran is based on the dual-energy gamma-ray transmission technique. The dominant advantage of the dual-energy gamma ray is its ability to
Methods
Twenty-eight samples representing all metallurgical coal types of the Shahroud mine were investigated in this study. These samples were crushed to <850 μm and stored in sealed containers to avoid oxidation. Conventional methods and nuclear techniques were used to measure the ash content of different coal layers of the Shahroud mine. In conventional methods, we used the ASTM D (3174) method to measure ash in studied samples. In addition, we used the ASTM D (3177) method to measure sulphur, D
Coal ash measurement by conventional method
Generally, the conventional methods (combustion method) are used for determination of the coal ash in the Shahroud mine. Before using the nuclear technique, we used the conventional method to measure coal ash in our samples.
In the conventional method, the coal samples are initially pulverized and crushed to <850 μm. One gram from each sample is heated to 850 °C for 3 h, and the coal ash percent is measured by analytical balance, Adcon. Then, the nuclear technique device obtains the amount of
Elemental analysis of coal ashes by XRF spectroscopy
The concentration of elements in coals is important for the ash percent and metallurgical uses. In this study, the X-ray fluorescence method was used for the elemental analysis of coal samples. Another purpose of our study was to examine the coal composition and to discuss its relationships with coal ash content with respect to the final metallurgical products.
Twenty-eight coal samples were collected from seven different layers (four samples from each layer) of the Shahroud coal mine. The ashes
Conclusions
An isotopic (nuclear) technique device designed in Iran works using dual-energy gamma rays for determination of the ash content in coal samples. The method is fast, economical, and easy to operate. For measurement, the instrument should be calibrated using calibration standards prepared from original coals. The result shows that the precision of the method depends on the accuracy of the calibration curves. Preparing appropriate samples, increasing the number of samples, and increasing the
Acknowledgements
The authors would like to thank H. Ghafourian, A. Abedinzadeh, and A. Naimpour for their guidance concerning these measurements in the Atomic Energy Organization of Iran. In addition, we would like to thank all the staff of the Shahroud coal mine for their generous help in collecting and analyzing the samples.
References (8)
- et al.
Feasibility studies of low energy gamma-ray techniques for on-line determination of ash content of coal on conveyors
International Journal of Applied Radiation and Isotopes
(1983) - et al.
Primary investigation of a design for a dual energy gamma-ray transmission gauge to determine the ash content of coal on a conveyor belt
Nuclear Geophysics
(1993) - et al.
Design and construction of gamma transmission gauge for determination of the ash content in coal
IAEA-TECDOC
(1995) - Esmaeilnia, A., 2003. Design and construction of a system for analysis of materials by nuclear techniques. Faculty of...
Cited by (35)
Accuracy enhancement of laser-induced breakdown spectroscopy by polarization spectrum fusion
2023, Spectrochimica Acta - Part B Atomic SpectroscopyA Bayesian optimal convolutional neural network approach for classification of coal and gangue with multispectral imaging
2022, Optics and Lasers in EngineeringFroth image feature engineering-based prediction method for concentrate ash content of coal flotation
2021, Minerals EngineeringQuantitative analysis of coal quality by mutual information-particle swarm optimization (MI-PSO) hybrid variable selection method coupled with spectral fusion strategy of laser-induced breakdown spectroscopy (LIBS) and fourier transform infrared spectroscopy (FTIR)
2021, Spectrochimica Acta - Part B Atomic SpectroscopyPrecise determination of soil structure parameters in a X-ray and γ-ray CT combination methodology
2019, Progress in Nuclear EnergyCitation Excerpt :The CT number of the voxels is affected by the electron density and the bulk density of the material. Variations in bulk density and soil-moister are related to variations in the CT matrix scanned at identical energy settings (Yazdia and Esmaeilnia, 2003; Pires et al., 2004; Carducci et al., 2017; Katuwal, 2017). The denominator Rμ,H2O is defined in Eq. (11).
A novel technique for online slurry grade detection based on EDXRF
2019, Minerals EngineeringCitation Excerpt :Spectral analyses have been widely discussed in research of online elemental assaying of slurry flow, where the primary techniques are dual-energy gamma-ray transmission, wavelength dispersion X-ray fluorescence spectrometry (WDXRF) and energy dispersion fluorescence spectrometry (EDXRF) (Zeng, 2008a, 2008b; Zhao and Zeng, 2009). However, the dual energy gamma ray device is based on dual-energy gamma ray transmission isotopes, which are quite radioactive and costly to operate and maintain (Yazdi and Esmaeilnia, 2003). While WDXRF has lower radioactivity levels, better steadiness and a wider range of elements can be detected, its setup includes large cooling equipment and requires some large installation spaces.