Caracterização de argilas e crostas lateríticas da porção nordeste do estado do Amazonas, visando aplicabilidade como pigmentos

Abstract

In the northeast portion of the State of Amazonas along the BR-174, BR-319 and AM-070, there are innumerable lateritic profiles, products of sedimentary rocks alteration of the Amazon basin. In these appear in abundance, clays and ferruginous crusts, that at the moment has its use restricted to the ceramics industry and the construction of road accesses, respectively. In this way, studying new forms of exploitation of such raw materials, can add value to the materials and help in the development of the said region. For this purpose, 10 lithotypes have been characterized in the physical, chemical and technological fields aiming at the use as pigments. The mineralogical assembly found is composed of Montmolironite, Kaolinite, Quartz, Illita, Anatase, Goethite, Muscovite and Hematite. It was verified a correlation between the mineralogy and color of these samples where the hematite and the goethite influence in the variability of the colors and the kaolinite in the luminosity and consequently in the tonality. All the samples presented pigment properties, differing only in the viscosity of the paints obtained in the test, where the samples with a higher amount of clay minerals resulted in more viscous paints, while the non-clay produced less viscous paints, it is therefore necessary to change the proportionality between resin, pigment and solvent, to 2: 2: 1 respectively, making it possible to make paints with similar viscosities. Such inks can be considered an ecological alternative for industrialized products, taking into consideration that the preparation does not generate residues and that the inorganic pigments have less environmental impact than the chemically synthesized dyes.