Deashing and desulphurization of fine oxidized coal by Falcon concentrator and flotation
Xiangnan Zhu 1,   Youjun Tao 1, 2  
,   Qixiao Sun 1,   Zhongpei Man 1,   Yushuai Xian 1
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School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
Youjun Tao   

China University of Mining and Technology, No.1 of daxue road, xuzhou, jiangsu province, 221116 xuzhou, China
Publication date: 2016-06-01
Physicochem. Probl. Miner. Process. 2016;52(2):634–646
Flotation and enhanced gravity separation based on different separation principles were carried out to investigate the desulphurization and deashing efficiency of fine oxidized coal. Surface properties of fresh and oxidized coals were tested by XPS and results showed that the contents of hydrophobic functional groups decreased while the content of hydrophilic functional groups increased after oxidization. Floatability and density analysis results showed that the floatability of coal samples decreased sharply because of oxidation, however, density composition of coal sample only had slight changes. Separation results showed that yields of gravity concentrates outclassed that of flotation concentrates, meanwhile, ash contents and sulfur contents of gravity concentrates were far lower than that of flotation concentrates. Yields and ash contents increased with the collector dosage and achieved to be 17.83 and 26.94% respectively when the collector dosage was 1600 g·Mg-1. Yields and ash contents of gravity concentrates decreased with the centrifugal force and increased with the recoil water flow with similar sulfur content. Clean coal with yield of 53.86%, ash content of 9.81%, sulfur content of 1.47% and with a corresponding desulphurization efficiency of 44.53% was achieved at centrifugal force of 107 g and recoil water flow of 13.3 dm3·min-1. For fine oxidized coal, enhanced gravity separation has a significant advantage of the separation efficiency compared with flotation.