Part of the book: Recent Developments in the Study of Recrystallization
Part of the book: Advanced Topics in Crystallization
Iron oxides were synthesized in conditions similar to those that prevail in deeps of the Red Sea (2–5M NaCl, temperatures 60–80°C, and pH 6.5–10.4). The main phase that was crystallized was submicron magnetite. Additional phases of feroxyhyte, goethite, and akagenéite were also detected. Magnetite morphology observed through high-resolution scanning electron microscopy (HRSEM) varied between euhedral plates and octahedral or unhedral crystals. The euhedral plates were probably crystallized pseudomorphically after platy green rust or Fe(OH)2 due to its quick crystallization. Size of magnetite varied between 18 and 45 nm. The addition of Si retarded crystal growth, and at Si/Fe = 0.5, short-range ordered phases are formed and not magnetite. This finding is in line with earlier laboratory experiments in which Si was found to retard goethite and lepidocrocite crystallization.
Part of the book: Iron and Iron Oxide Material