Topic
Magnetite
About: Magnetite is a research topic. Over the lifetime, 10277 publications have been published within this topic receiving 278071 citations.
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TL;DR: In this article, the magnetic susceptibility of soil minerals is discussed, and in particular that of the ferrimagnetic minerals, maghemite, magnetite, and the titanomagnetites since one or more of these usually dominates soil magnetic properties.
Abstract: Summary
The magnetic susceptibility of soil minerals is discussed, and in particular that of the ferrimagnetic minerals, maghemite, magnetite, and the titanomagnetites since one or more of these usually dominates soil magnetic properties. The magnetic susceptibility of soil depends on the shape, size, and concentration of these minerals as well as on the method of measurement. Measurements performed in a weak alternating magnetic field are the most reliable.
The identification, formation, and occurrence of soil maghemite is considered in detail since it is usually of pedogenic origin and occurs in (magnetically) detectable amounts in most soils. Moderate concentrations (>1 per cent) of magnetite or titanomagnetite in soils may be accurately measured if some of the material is first magnetically separated and its susceptibility determined. An example is given of the use of susceptibility measurements. Pedogenic maghemite may be determined in soils developed from parent materials of low susceptibility. A very rough value of 8.8 × 10−4 m3 kg−1 is suggested for the mass susceptibility of such maghemite (excluding magnetic concretions).
Although susceptibility has been suggested as an indicator of soil forming processes, this is only possible within an area containing fairly uniform parent material.
623 citations
TL;DR: In this article, a calibrated chemical extraction scheme was developed for partitioning reactive Fe(III) minerals in the solid phase of marine sediments, and the following chemical extractants were used: ascorbate, oxalate, dithionite, and HC1 (0.5 M).
620 citations
01 Mar 1980
TL;DR: In this article, the formation of iron oxides by aging ferrous hydroxide gels at elevated temperatures was studied as a function of various parameters, including the nature of the anions present in the system.
Abstract: The formation of iron (hydrous) oxides by aging ferrous hydroxide gels at elevated temperatures was studied as a function of various parameters. It was found that the composition and the morphology of the resulting solids depended strongly on the nature of the anions present in the system. Spherical magnetite particles of narrow size distribution, with mean diameters ranging between 0.03 and 1.1 μm, were obtained if FeSO4 was interacted with KOH in the presence of nitrate ion and the resulting gelatinous suspension was kept at 90°C for several hours. The particle size distribution of the magnetite sol was affected by the excess concentration of Fe(II) species in equilibrium with the ferrous hydroxide precipitate. If oxygen was present in addition to nitrate ion, rodlike α-FeOOH particles crystallized along with the magnetite on aging of some ferrous hydroxide gels. A mechanism of the magnetite formation under the conditions of these experiments is offered.
610 citations
TL;DR: In this article, the authors investigated the pathways and mechanisms of secondary mineralization during dissimilatory iron reduction by a common iron-reducing bacterium, Shewanella putrefaciens (strain CN32), of 2-line ferrihydrite under advective flow conditions.
599 citations
TL;DR: Iron oxide (Fe(3)O(4), magnetite) nanocrystals of 6 to 30 nm with narrow size distributions (sigma = 5-10%) were prepared by the pyrolysis of iron carboxylate salts.
597 citations