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Controlling particle size during anatase precipitation
Author(s) -
Sathyamoorthy Sekhar,
Moggridge Geoff D.,
Hounslow Michael J.
Publication year - 2001
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690470912
Subject(s) - agglomerate , anatase , filtration (mathematics) , precipitation , crystal (programming language) , chemical engineering , particle size , seeding , materials science , grain size , seed crystal , particle (ecology) , particle size distribution , mineralogy , chemistry , crystallography , metallurgy , composite material , single crystal , organic chemistry , geology , meteorology , mathematics , catalysis , statistics , physics , aerospace engineering , oceanography , computer science , engineering , photocatalysis , programming language
Titanium dioxide particles in the form of anatase are precipitated from concentrated titanyl sulfate solution in the sulfate process, which are then recovered by a filtration process downstream of the precipitation stage. A previous study by Sathyamoorthy et al. showed that the final anatase particles are aggregates (1‐2 μm) consisting of numerous crystals (7–8 nm) arranged in primary agglomerates (60–100 nm). Pigment quality is determined by crystal and primary agglomerate size. One way of improving filtration rate is by the formation of larger aggregates, while maintaining the crystal and primary agglomerate size at optimum values. In a new seeding procedure proposed, the controlled inoculation of seeds used in industry is combined with a new type of seed (Large Seeds). The new seeding procedure has the potential to increase downstream filtration efficiency by increasing aggregate size, while maintaining crystal and primary agglomerate sizes close to the values correctly obtained in industry. High yield in the precipitation process is also maintained.