Comportamento térmico de óxidos de ferro presentes em solos da savana de Roraima

Abstract

In this work was studied a soil sequence sample according to the profiles P1, P2, P3, P4 and P5, aiming to identify through analysis diffractogram, iron oxides, from the concentrated samples of induced magnetic soils collected on land near Amajarí, Boa Vista, Bonfim and Alto Alegre, Roraima, to provide data for future projects related to land use areas in which these profiles are located. In a first step the samples were collected in surface and subsurface horizons were defined in 0.0 to 0.10 m: 0.60 to 1.00 m and 0.80 to 1.00 I brought to the laboratory of Soil Management Center of Agricultural Sciences, where he proceeded to treatment and subsequent thinning of the sand samples total (TFSA), and the separation of the magnetic concentrate. In the second step, the treated samples were brought to the Laboratory of Magnetic Properties on the campus of Paricarana where mineralogical analysis was performed using the technique of X-ray diffraction. It was observed the predominance of quartz and kaolinite between silicate minerals in the sample of total sand, and between the oxides, we observed the presence of hematite, goethite, magnetite and anatase, where the hematite prevailed in four of the five profiles except the profile P1. Soils were analyzed at three different temperatures, 25 ° C, 300 ° C and 700 ° C, the heat treatment significantly transformed the oxides of iron, increasing the area of hematite.