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Ultrasound assisted wet stirred media mill of high concentration LiFePO 4 and catalysts
Author(s) -
Li He,
Rostamizadeh Mohammad,
Mameri Kahina,
Boffito Daria C.,
Saadatkhah Nooshin,
Rigamonti Marco Giulio,
Patience Gregory S.
Publication year - 2019
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23212
Subject(s) - materials science , particle size , slurry , chemical engineering , suspension (topology) , grinding , particle (ecology) , ultrasonic sensor , agglomerate , analytical chemistry (journal) , composite material , chromatography , chemistry , oceanography , physics , mathematics , homotopy , acoustics , pure mathematics , engineering , geology
Abstract Wet media mills grind solids to the nanometric size and the performance of the mills depends on solids loading, particle morphology, surfactant concentration, and material characteristics. As the particle size decreases, they tend to form clusters that reduce the grinding efficiency. Ultrasound deagglomerates these clusters thereby increasing efficiency but, surprisingly, it can operate at higher solids concentrations. We processed suspensions of LiFePO 4 (LFP) with a yttria stabilized zirconia media with a size from 0.3 mm to 0.4 mm, and surfactant‐to‐LFP mass ratio 0.008. The combined method ground the particle size from 35 μ m down to 0.2 μ m in 90 min with a throughput of 0.68 kg LFP / kg media /h. We also tested the improved wet media milling on two catalysts: ( WO 3 / TiO 2 and vanadyl pyrophosphate (VPP) precursor) to confirm the trends. We adopt a model for the steady state and repeatable micronizing process with ultrasonic assistance. According to TEM imaging the WO 3 / TiO 2 catalyst primary particles (20 nm) are much smaller than the agglomerated ones measured by laser diffraction (470 nm). VPP precursor slurry is normally an unstable suspension that is hard to mill. It formed agglomerates with recrystallized silica and VPP flocculation. The ultrasound‐assisted wet milling technique produced nanometer scale particles (180 nm), which is otherwise impossible. We developed and updated the steady state micronizing process with ultrasonic assistance using a simplified population balance model. The model accounts for R 2 > 0.95 of the variance in the experimental data.