Factors in the Precipitation Medium Governing Morphology and Structure of Haematite Particles in Forced Hydrolysis Reaction
✍ Scribed by Kazuhiko Kandori; Yoshie Nakamoto; Akemi Yasukawa; Tatsuo Ishikawa
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 395 KB
- Volume
- 202
- Category
- Article
- ISSN
- 0021-9797
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✦ Synopsis
particles), synthesized from a forced hydrolysis reaction of The effects of dioxane (DX) on morphology and texture of an FeCl 3 -HCl solution, developed by Matijevic ´and cohaematite particles produced from a forced hydrolysis reaction of workers (1, 3, 5). Serna and co-workers reported that spheri-FeCl 3 -HCl solution were investigated by TEM, XRD, XFS, FTIR, cal particles are obtained by the classical La Mer mechanism, TG-DTA, N 2 and H 2 O adsorption, and zeta potential measurefrom TEM observations and the XRD method, while ellipments. The spherical shape of haematite particles produced below soidal particles produced with small amounts of phosphate the DX concentration of 10 vol% (diameters: 600-1000 nm) was ions are formed by an aggregation process from smaller changed to cubic for particles produced at more than 12 vol% primary particles (6-8). When TEM measurement was em-DX (mean edge lengths: 900-1200 nm). The rod-like b-FeOOH ployed, a similar aggregation mechanism was also reported particles were precipitated as cubic particles at the DX concentration ¢28 vol%. TEM and XRD suggested that the haematite parti-on the formation of cubic particles by Bailey et al. (9). cles formed in the presence of DX are polycrystalline with an However, the known characteristics of the particles used in enlarged c dimension in a unit cell. TG and FTIR indicated that these studies are scarce, and little is known about either the the haematite particles produced with DX are hydrohaematite formation process or the particularly structural character of possessing OH 0 ions in the lattice. The results obtained in the these uniform particles. Recently, the authors produced small present study revealed that variation of the polarity of the medium spherical (diameter: ca. 100 nm), cubic (edge length: ca. 1 with addition of DX is a determining factor of the particle size mm), large spherical (diameter: ca. 820 nm), and diamondand shape rather than the interfacial tension of the medium and like (long axis length: ca. 60 nm) haematite particles by the particles. ᭧ 1998 Academic Press the same forced hydrolysis reaction and clarified that the