Enhanced separation efficiency of low–rank coal using waste engine oil as a flotation collector
Ming Li 1
Yangchao Xia 1
Fangyu Guo 1
Guoqiang Rong 1
Guosheng Li 1
Baolin Xu 2
Yaowen Xing 1
Xiahui Gui 1  
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China University of Mining and Technology
Shandong chaomei clean energy co. LTD, Taian 271000, Shandong, China
Xiahui Gui   

China University of Mining and Technology
Publication date: 2019-12-23
Physicochem. Probl. Miner. Process. 2020;56(2):252–263
Because of the rich oxygen-containing functional groups and developed pores on the surface of low-rank coal, it is difficult to realize efficient separation during low-rank coal flotation using common oil collectors. Waste engine oil (WEO) is abundant in polar oxygen-containing functional groups and could be an alternative collector. In this study, the effect of WEO on low-rank coal floatation was assessed and engine oil (EO) was also used for comparison. The results show that the separation efficiency of low-rank coal can be significantly improved using WEO; additionally, 96.73% of the clean coal yield can be obtained when the WEO dosage was only 4 kg/t. Compared with EO, the bubble–particle induction time in the presence of WEO shortened from 430 to 220 ms. Moreover, more low-rank coal particles were captured and adhered to the bubble surface using WEO, which indicated a higher probability of bubble–particle attachment. Nonpolar components, polar components and metal ions synergistically promote the flotation separation enhancement of low-rank coal using WEO.