Electrostatic beneficiation of fly ash in a free-falling system

Zhang, Lifeng; Hou, Jiangtian; Bi, Xiaotao; Grace, John R.; Janke, Travis; Arato, Claudio

doi:10.1016/j.partic.2011.07.006

Cited by 13 publications

(2 citation statements)

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“…Comparing the charge density results from PE with narrow and wide size distributions, the effect of particle size distribution was studied. Particles with a wider size distribution generated a smaller net charge density, because of the bipolar charging created by small and large particles. − Most commonly, smaller particles have a tendency to be charged negatively and larger particles have a tendency to be charged positively, − but opposite results have also been reported. , Monosized particles result in the same polarity of charge on particles from particle–wall contacts but less or no charge generation due to particle–particle contacts. As a result, the net charge density could be larger for particles with a narrow size distribution.…”

Section: Resultsmentioning

confidence: 99%

Monitoring Electrostatics and Hydrodynamics in Gas–Solid Bubbling Fluidized Beds Using Novel Electrostatic Probes

Grace

2015

Ind. Eng. Chem. Res.

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The ability of recently developed novel electrostatic probes to monitor particle charge density and hydrodynamics in freely bubbling two-and three-dimensional fluidized beds of glass beads and polyethylene particles is demonstrated. Particle charge density and bubble properties in the beds were altered by abruptly changing superficial gas velocity or by impulsively adding antistatic agent to the bed. The probes were then utilized to quantitatively monitor the particle charge density and bubble rise velocity. The current signals from the probes responded quickly and significantly to abrupt changes in the superficial gas velocity. By analyzing time-series signals from the probes, the particle charge density and the bubble rise velocity deduced from the probes were found to be of similar order of magnitudes and changed consistently with those obtained from Faraday cup and video measurements. Charge densities from the Faraday cup decreased when an antistatic agent was added, as registered by the probe.

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Section: Resultsmentioning

confidence: 99%

Monitoring Electrostatics and Hydrodynamics in Gas–Solid Bubbling Fluidized Beds Using Novel Electrostatic Probes

Grace

2015

Ind. Eng. Chem. Res.

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“…Calin et al reported the numerical simulation and the experimental study of chargedparticle trajectories in a free-fall electrostatic separator with different feed input angles, and proved that the adjustment of the feed input angle may contributed significantly to a successful separation of granular materials (34). Zhang and Tao et al investigated triboelectric separation of fly ash, and analyzed the trajectory of charged particles in an electric field based on the force balance (35,36). Doney et al studied the aerodynamic behavior of charged particles in an electrostatic separator, and obtained a time-averaged image of the separation by laser imaging technique (37).…”

Section: Introductionmentioning

confidence: 99%

Study on the Dynamics of Tribocharged Coal and Mineral Particles in Free-Fall Triboelectric Separator

Wang

Chen

Cai

et al. 2014

Separation Science and Technology

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The dynamics of 2.0∼0.8 mm or 0.8∼0.5 mm size fraction of tribocharged organic coal, pyrite, and calcite particles were studied under the electric field using the high-speed dynamic camera combined with high-speed motion analysis system. Motion images of these particles were obtained and used to analyze their dynamic parameters. Organic coal particles tribocharged positively move to the negative plate, while pyrite and calcite particles reach the positive plate under the influence of electric force. These results indicate that the trajectories of all 2.0∼0.8 mm particles are similar to parabolic curves. For 0.8∼0.5 mm particles, the trajectories are approximate straight line, except for the calcite. The vertical velocities of all particles increase with a fluctuant acceleration as a result of gravity and drag force. The horizontal velocities of all particles vary slightly. The dynamics of 0.8∼0.5 mm particles prove that size is very important for the triboelectric separation. The actions of electric force and drag force are increased with the decrease of particle size.

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