Effect of the degree of polymerization of nonylphenol polyoxyethylene ether on the dewatering of low-rank coal
Lin Li 1,   Meng He 1,   Mingpu Liu 1,   Mengyu Lin 1,   Shanpei Hu 1,   Hao Yu 1,   Qingbiao Wang 2,   Xiaofang You 1  
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Shandong University of Science and Technology
Shandong University of Science and Technology, Tai’an,
Xiaofang You   

Shandong University of Science and Technology
Publication date: 2020-06-30
Physicochem. Probl. Miner. Process. 2020;56(4):723–736
In this study, we investigated the effect of the hydrophilic ethylene oxide chain lengths (i.e., degree of polymerization) of nonylphenol polyoxyethylene ether (NPEO-x, x = 8, 10, and 12) on the dewatering of low-rank coal slime through dewatering and adsorption experiments and X-ray photoelectron spectroscopy (XPS) measurements. The dewatering experiments showed that the adsorption of NPEO changed the water content of the low-rank coal slime: NPEO-8 achieved the best effect, followed, in decreasing order, by NPEO-10 and NPEO-12. Adsorption experiments revealed that the adsorption isotherms of NPEO-x on the low-rank coal surface conform with the Langmuir model, and its adsorption kinetics follow the pseudo-second-order kinetic equation. Furthermore, the adsorption is a spontaneous process and controlled by both intraparticle diffusion and liquid film diffusion. The XPS results showed that the adsorption of NPEO-x decreased the content of oxygen-containing groups and, thus, improved the hydrophobicity of the low-rank coal surface. Further, the use of NPEO-x with a low degree of polymerization (x = 8) improves the hydrophobicity of the coal surface and decreases the water content of low-rank coal slime.