title: Effect of pH on the flocculation behaviors of kaolin using a pH-sensitive copolymer.
abstract: pH-sensitive copolymers have been widely introduced to achieve rapid dewatering and consolidation of solids in mining and oil sands processing wastes. But no more attention has been given to the flocculation efficiency of solid suspensions as a function of pH using pH-sensitive copolymer. In this study, a pH-sensitive copolymer was synthesized and employed to investigate the flocculation behaviors of kaolin by focused beam reflectance measurement (FBRM). A titration test was introduced to characterize the copolymer conformation transition. The results demonstrated that at pH ranging from 3 to 6, with the pH increase, the zeta potential magnitude of kaolin particles increased, resulting in the repulsive forces between particles increasing. However, the hydrophobicity of kaolin increased as the pH increased. Thus, the hydrophobic forces could neutralize a part of the repulsive forces between particles and result in good and similar flocculation performances. At the pH greater than 6, the zeta potential magnitude of kaolin particles and copolymer molecules increased significantly, and the repulsive force between kaolin particles increased after copolymer addition due to the kaolin particles being more negatively charged, which resulted in poor flocculation efficiency and cloudy supernatant. It was concluded that the pH-sensitive copolymer could achieve both perfect flocculation efficiency and low moisture of filter cake at the isoelectric point of copolymer.
authors: School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou 221116, Jiangsu, China; Chemical & Materials Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2V4; National Engineering Research Center of Coal Preparation and Purification, Xuzhou 221116, Jiangsu, China E-mail: caoyj@cumt.edu.cn.
authors: Shulei
authors: S
authors: Li
authors: School of Chemical Engineering and Technology, China University of Mining & Technology, Xuzhou 221116, Jiangsu, China; National Engineering Research Center of Coal Preparation and Purification, Xuzhou 221116, Jiangsu, China E-mail: caoyj@cumt.edu.cn.
authors: Lihui
authors: L
authors: Gao
authors: National Engineering Research Center of Coal Preparation and Purification, Xuzhou 221116, Jiangsu, China E-mail: caoyj@cumt.edu.cn.
authors: Yijun
authors: Y
authors: Cao
authors: National Engineering Research Center of Coal Preparation and Purification, Xuzhou 221116, Jiangsu, China E-mail: caoyj@cumt.edu.cn.
authors: Xiahui
authors: X
authors: Gui
authors: School of Chemistry and Chemical Engineering, Xi' An University of Science and Technology, Xi' an 710054, Shaanxi, China and Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining & Technology, Xuzhou 221116, Jiangsu, China.
authors: Zhen
authors: Z
authors: Li
mesh_terms: D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000737:chemistry*; D061329:Oil and Gas Fields; D011108:Polymers / Q000737:chemistry*
chemical_list: D011108:Polymers; D007616:Kaolin