Ultrasonic-assisted flocculation and sedimentation of coal slime water using the Taguchi method

ABSTRACTAs the intensity of mining increases, the gangue content in coal slime water increases, leading to difficulties in settling suspended particles. In recent years, ultrasound technology has received much attention in the field of water treatment due to its high efficiency and convenience, and coal slime water undergoes ultrasonic pretreatment to improve flocculation. This study explored the effects of four factors, namely ultrasonic power, ultrasonic time, flocculant dosage, and coal slime water concentration, on the flocculation efficiency of coal slime water using an orthogonal design. The optimum conditions for ultrasound-assisted coal slime water flocculation were found to be an ultrasonic power value of 192 W, an ultrasonic time of 8 min, pH 8, a flocculant dosage of 24 mg/L, and a coal slime water concentration of 30 g/L. The flocculation efficiency reached 92.64%. After a certain time of ultrasonic pretreatment (8 min), there was a reduction in the amount of clay on the surface of the coal slime particles, the potential decreased to −3.07 mV, and the average and fractal sizes of the flocs were 80.45 µm and 2.01, respectively. A range of methods was used to confirm that the settling effect of the coal slime water had been improved by ultrasonic pretreatment.KEYWORDS: Ultrasonic pretreatmentflocculantcoal slime waterflocculationTaguchi method AcknowledgementsThis work is supported by Natural Science Foundation of Heilongjiang Province (LH2020E124). The authors also gratefully acknowledge financial support from the National Natural Science Foundation of China (Grant No. 52204296).Disclosure statementThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.Author contributionsShufang Ding: conceptualization, resources, data curation, writing – original draft, writing – review & editing, visualization, supervision, project administration, funding acquisition; Fengjiao Pan: interpretation of data, formal analysis and investigation; Shaoqi Zhou: methodology, software, validation, formal analysis, investigation, writing – original draft; Xiangning Bu: review & editing, visualization, supervision; Muidh Alheshibri: review & editing.Additional informationFundingThe work was supported by the National Natural Science Foundation of China [52204296]; Natural Science Foundation of Heilongjiang Province [LH2020E124].Notes on contributorsShufang DingShufang Ding, associate professor of heilongjiang university of science and technology, graduated with master's degree in Mineral Processing Engineering from China University of Mining and Technology, Beijing, China, in 2006. She is mainly engaged in the research of flocculation and sedimentation of coal slurry water and graphite beneficiation. She has obtained 10 patents, including 2 invention patents and 8 utility model patents. She has published more than 10 papers, including 2 EI search papers and 1 SCI search paper, and has published 6 textbooks and monographs as chief editor and associate editor.Fengjiao PanFengjiao Pan, M.S., graduated from Heilongjiang University of Science and Technology in 2023 with a master's degree in mineral processing engineering. She is mainly engaged in the research of polymer pharmaceuticals and flocculation and sedimentation of coal slurry water. She has participated in the completion of two scientific and technological projects of Heilongjiang Provincial Natural Fund and Provincial Education Department. She has published 5 papers.Shaoqi ZhouZhou Shaoqi is presently a PhD candidate specializing in mineral processing engineering at China University of Mining and Technology. His primary research focus revolves around the preparation and characterization of micro-nanobubbles. Additionally, he is actively engaged in exploring the role of micro-nanobubbles in the flotation of fine minerals. He has published more than 20 academic papers.Xiangning BuDr. Xiangning Bu started to work as a lecturer in the School of Chemical and Engineering Technology at the same university from 2021 to the present. Dr. Bu’s current research interests include the advanced green and sustainable chemical and physical technologies for resources recycling of solid wastes; enhancement in the flotation performance of fine/ultrafine particles using hydrodynamic cavitation and/or ultrasound. He has over 70 publications in these areas.Muidh AlheshibriDr. Muidh Alheshibri is an Assistant Professor of Physics at Jubail Industrial College. He has published over 33 peer-reviewed articles in refereed high-quality journals, including journal of colloids and interface sciences, Langmuir, current opinion in colloid and interface science, and applied physics letters. His work has been cited over 1300 times. He served as a reviewer for several journals.