Potentially useful elements (Al, Fe, Ga, Ge, U) in coal gangue: a case study in Weibei coal mining area, Shaanxi Province, northwestern China

Abstract

Coal gangue has become one of the largest industrial solid waste in China, but it is also a kind of reserve resources. Representative coal gangue samples from different coal mines (mainly in Permo-Carboniferous and Jurassic) in Weibei area in Shaanxi Province are collected, and potentially useful elements (Al, Fe, Ga, Ge, U) in coal gangue are analyzed. The results show that the reserves of Al and Fe in Chinese coal gangue are 262 million tons and 196 million tons, respectively, based on the geometric mean values of AlO (15.18%, weight percent) and FeO (6.24%, weight percent). Meanwhile, the crude reserves estimation of Ga, Ge, and U are 55,282, 6867, and 32,981 tons, respectively, based on the weighted mean contents of Ga, Ge, and U in coal gangue at 17.55, 2.18, and 10.47 mg/kg, respectively. Furthermore, Ga and Al contents in quite a large number of coal gangue mines exceed the cutoff value, which has a prospect of development and utilization from coal gangue. The policy implications from this study may include that (1) recycling of useful elements in Chinese coal gangue should be treated as an integral part of sustainable development with professional legislations and (2) establishing a basic database of coal gangue and authoritative system with relevant departments for solid waste management may effectively improve comprehensive utilization of coal gangue in the future.

Enrichment of Li–Ga–Zr–Hf and Se–Mo–Cr–V–As–Pb Assemblages in the No. 11 Superhigh Organic Sulfur Coal from the Sangshuping Coal Mine, Weibei Coalfield, Shaanxi, North China

“…The Weibei coalfield lies on the southwestern edge of the North China block at the southeast corner of the Ordos basin and consists of numerous coal beds of the Permo-Carboniferous age [1]. The coalfield is 200 km long from east to west, 30-55 km wide from north to south, and has a coal-bearing area of nearly 10,000 km 2 that possesses enormous coal resources (up to 83 GT) [28].…”

“…The Weibei Carboniferous-Permian coalfield is a very important coal resource base in Shaanxi, North China [1]. Several researchers have studied the mineralogical and geochemical characteristics of the Weibei coal, and several critical metals, including Ga, Li, Nb, and Zr, have been found enriched in the Weibei coalfield, making Weibei coal a potential source for recovery of critical metals.…”

Grouting mechanism and experimental study of goaf considering filtration effect

“…Large-scale and high-intensity mining activities and the utilization of coal resources have produced a large amount of solid waste of coal gangue [1][2][3], occupying a large number of land resources and polluting air, groundwater and soil, resulting in a series of ecological, environmental problems [4][5][6]. The coal gangue and water are mixed into a certain concentration of gangue slurry through the underground slurry preparation system, and the goaf caving zone is filled with adjacent grouting to realize the harmless disposal of coal gangue under the low interference condition of the working face [7,8]. The filtration effect mainly occurs in the flow process of suspension in porous media.…”

Evaluation of Mechanical Properties and Microscopic Structure of Coal Gangue after Aqueous Solution Treatment

“…In addition, if atmospheric precipitation seeps into the self-igniting coal gangue pile, the rapid expansion of heated air will lead to the risk of dump expansion or explosion [9]. The contradiction between the concern of resource depletion and environmental damage caused by fuel consumption is becoming more and more prominent [10,11]. Therefore, the harmless treatment and utilization of coal gangue has increasingly become the focus of attention of researchers at present.…”