The most frequently investigated salts in coal flotation are chlorides. However, seawater contains additional salts such as sulfates. In coal flotation, magnesium chlorides showed the best results in terms of higher yield and lower ash content compared to the other magnesium salts studied. Therefore, two magnesium salts were tested in this investigation, namely magnesium chloride and magnesium sulfate. The effect of the magnesium salts as well as the optimization of coal flotation were investigated by statistical design of experiments in terms of pulp density, particle size, conditioning time and different dosages of MgCl2 and MgSO4. The flotation results obtained by statistical design show that the ash content was lowest at 8.2% when a mixture of 2 kg/t MgSO4 and 2 kg/t MgCl2 has been used, with pulp density 20%, particle size 400 lm and conditioning time 15 min. The particle size plays an important role in reducing the ash content when the conditioning time has been extended and pulp density has been reduced. The strong interaction between the salts hinders the reduction of the ash content to less than 8.2%.
Die am häufigsten untersuchten Salze bei der Kohleflotation sind Chloride. Das Meerwasser enthält jedoch andere Salze wie z.B. Sulfate. Bei der Kohleflotation zeigten Magnesiumchloride im Vergleich zu den anderen hier untersuchten Magnesiumsalzen die besten Ergebnisse in Bezug auf höhere Ausbeute und geringeren Aschegehalt. Daher wurden in dieser Arbeit zwei Magnesiumsalze getestet, nämlich Magnesiumchlorid und Magnesiumsulfat. Die Wirkung der Magnesiumsalze sowie die Optimierung der Kohleflotation wurden durch statistische Versuchsplanung in Bezug auf Zellstoffdichte, Partikelgröße, Konditionierungszeit und verschiedene Dosierungen von MgCl2 und MgSO4 untersucht. Die mit statistischer Versuchsplanung erhaltenen Flotationsergebnisse zeigten, dass der Aschegehalt mit 8,2% am geringsten war, wenn eine Mischung aus 2 kg/t MgSO4 und 2 kg/t MgCl2 verwendet wurde und die Zellstoffdichte 20%, die Partikelgröße 400 lm und Konditionierungszeit 15 Minuten betrugen. Die Partikelgröße spielt eine wichtige Rolle bei der Verringerung des Aschegehalts, wenn die Konditionierungszeit verlängert und Zellstoffdichte verringert worden ist. Die starke Wechselwirkung zwischen den Salzen behindert die Verringerung des Aschegehalts auf weniger als 8,2%.
About the authors
Rawya Gamal received her Bachelor of Science degree in Mining Engineering from Cairo University, Egypt in 2013. She got a demonstrator position in the same department. She earned a Master of Science in Mining Engineering in 2019. Finally, she works in her PhD degree in Mineral processing technology and application of surfactants in mineral industry.
Nader Ahmed A. Edries (Nader Edress) got his Ph. D. in geology from Charles University in Prague 2007 (Czechia), currently works at the Department of Geology, Helwan University (Cairo, Egypt). Nader was an associated member of ICCP (International Committee for Coal and Organic Petrology) from 2007–2012. Nader do researches in Coal Geology, Organic Petrology, Organic Sedimentary Rocks, Sedimentary Environments, and Paleoecology. Their current project is ’Coal and Coal Bearing Deposits in Egypt’.
Khaled Abuhasel received the B.Sc. and M.Sc. degrees from the University of Central Florida, USA, in 2009 and 2010, respectively, and the Ph.D. degree from New Mexico State University, Las Cruces, NM, USA, in 2012, all in industrial engineering. He is currently an Associate Professor in Mechanical Engineering Department, University of Bisha, Saudi Arabia. He holds three U.S. patents, and more than 46 publications in very reputable journals and conferences proceeding. His research interests include optimization, systems engineering, health care systems, intelligent systems, artificial neural network methodologies, and statistical analysis.
Ayman A. El-Midany is currently a Professor and Head of Mining Engineering program, Cairo University, Egypt. He was graduated from Mining Engineering – Cairo University in 1991. He received his M. Sc. from the same university in 1997. Prof. El-Midany has got his Ph.D in 2004 from Material Science and Engineering – Florida University, USA. He has various teaching and research interests in the fields of Mineral processing, applied surface and colloid chemistry, chemical metallurgical and environmental engineering. He has published several papers on particle technology and interfacial phenomena. He participated in different industrial projects related to mining and mineral industries.
Salah E. El-Mofty is currently a vice dean of graduate studies, Civil Engineering, University of Bisha, Saudi Arabia. He is an Emeritus professor of surface chemistry and mineral engineering at Faculty of Engineering, Cairo University. His research activities are in stone conservation, surfactant and polymeric coating, coal and oil shale processing, mineral processing.
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