Magnetic seeding sedimentation (MSS) of coal slimes

International Conference on Energy Engineering and Environmental Protection 2016

能源学;生态环境科学

Wu, Xiqing^1 ; Yue, Tao^1 ; Dai, Liang^1

School of Minerals Processing and Bioengineering, Central South University, Changsha

410083, China^1

关键词: Coal particles;    Fine particles;    Low magnetic fields;    Magnetic agglomeration;    Magnetic field strengths;    Magnetic interactions;    Magnetic seeding;    Vibrating sample magnetometer;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/52/1/012003/pdf
DOI  :  10.1088/1742-6596/52/1/012003

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

Magnetic seeding sedimentation (MSS), i.e. adding magnetic seeds and pre-magnetization for sedimentation, is a technique especially for sedimentation of fine slimes, improving the sedimentation performance by introducing the magnetic interactions between particles in a suspension and enlarging the apparent size of the fine particles. The fine coal slimes with a size of 66.68%-38μm were investigated by the MSS. Sedimentation tests were conducted, and some measurements, such as laser size analysis, magnetic susceptibility by vibrating sample magnetometer (VSM), were also applied in order to probe the mechanism of the MSS. Based on the tests, measurements and calculations it was demonstrated that the sedimentation of coal slimes increased with the additions of the magnetic seeds, and in the presence of the polyacrylamide, and also there appeared a relatively large apparent size of slimes after additions of magnetic seeds and/or polyacrylamide. So, the reason for the influence of MSS lies in fact that the presence of the polyacrylamide intensified the adsorption of magnetic seeds on the coal particles and the coverage of the magnetic seeds on the coal surface from 0.2% wt. to1.3% wt., resulting in increased magnetic susceptibility of coal particles from 9.13×10-9m3/kg to 22.17×10-9m3/kg and thus a low magnetic field strength of pre-magnetization needed for the magnetic agglomeration to happen among the coal particles (the threshold of magnetic field strength for agglomeration) from 602mT to 24mT prior to proper sedimentation.