Abstract

GOMEZ SAMUS, Mauro et al. Efectos del contenido de CaCO₃ inicial en las propiedades magnéticas de sedimentos calcinados. Resultados preliminares. Bol. Soc. Geol. Mex [online]. 2017, vol.69, n.1, pp.261-278. ISSN 1405-3322.

In this work, the influence of the initial CaCO3, on the magnetic properties of calcined sediments, is evaluated. This contribution is part of a wider study, about magnetic mineralogy developed from sediment calcination of different compositions at diverse temperatures. High temperatures in sediments cause chemical-mineralogical transformations that depend, mainly, upon their original composition. Some examples of this are burned soils, pyrometamorphic and diagenetic processes or meteorite impact zones. Transformations could be similar, even analogous, to some industrial processes, like bricks, ceramics and cements manufacturing. The determination of magnetic parameters (magnetic susceptibility and isothermal remanent magnetization) and major chemical elements was made in sediments with contrasting amounts of CaCO3. The thermal process was performed at 1000 ºC in air atmosphere. Before heating, the behavior of magnetic composition indicates a significant homogeneity as regarding the magnetic parameters. These behaviors are undoubtedly related to the ferrimagnetic series of titanomagnetites and probably to the maghemite signal as well. In contrast, calcined samples presented magnetic records that vary noteworthy in relation to the CaO (or initial CaCO3) content. After heating, the samples with lower CaO (< 4 %) concentrations showed a magnetic signal related to antiferromagnetic minerals, like hematite. The samples with higher CaO contents (8-29 %) showed a magnetic signal related to ferrimagnetic minerals. Besides, all calcined samples showed a high contribution of nanoparticles with superparamagnetic properties.

Keywords : Magnetic parameters; calcined sediments; bricks; cements; burned soils.

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