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ABSTRACT
Dry triboelectric separation of coal depends on tribocharge difference of the coal and gangue minerals. A suitable tribocharger material which makes the coal and minerals tribocharged of opposite polarity is of great importance for triboelectric separation. In this paper, the composition of coal was analyzed by x-ray diffraction (XRD), and the triboelectric characteristics of coal and other ash-forming minerals were tested using stainless steel (SS), polyvinyl chloride (PVC), pentatricopeptide repeats (PPR), polyfluortetraethylene (PPFT), and polymethyl methacrylate (PMMA) tribochargers in lab triboelectric unit. The charge−mass ratio of coal and mineral particles were presented and evaluated. Infrared spectroscopy was adopted to analyze the different tribocharge properties between clean coal and minerals. The results show that the gangue minerals in coal are mainly pyrite, kaolin, calcite, dolomite, and quartz. The conductive mineral had the lowest chargeability, especially tribocharged with conductive material. Compared with the inorganic surface, the organic surface is easy to lose electrons and charge positively. According to the triboelectric characteristics of coal and minerals, PMMA is more suitable as tribocharger material for triboelectric separation of pulverized coal compared with PVC, PPFT, PPR, and SS. The better separation efficiency of Tai Xi anthracite coal is obtained by using PMMA tribocharger.