Estudo mineralógico e tecnológico do caulim do meio-norte nordestino

Abstract

Kaolin deposits occur in various regions of the world. The demand for higher-quality products in industries, combined with the need for efficiency in production processes, has intensified the criteria for the characteristics of raw materials and additives used, including kaolin. In this context, this work presents a study of the mineralogical and technological properties of kaolin samples from the Mid-North region of the Northeast, specifically from the municipalities of Caxias (MA), Floriano (PI), and Palmeirais (PI). Physicochemical characterizations were performed using X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size analysis, thermogravimetry (TGA/DTG), and plasticity tests, in addition to the technological evaluation of specimens sintered at 900 °C and 1000 °C. The results showed significant variations between the samples in terms of chemical composition and thermal behavior, with a predominance of kaolinite and variable presence of impurities such as quartz, mica, and iron oxides. Technologically, it was demonstrated that increasing the temperature promotes improvements in physical properties, such as densification and shrinkage, although the mechanical strength (TRF) values remain low for structural applications. A sample from Floriano stood out for its high mineralogical purity and thermal stability. These results indicate promising prospects for the use of samples in non-structural ceramic products and highlight the economic and technological significance of mineral exploration in the Mid-North Northeast region. The Floriano sample stood out for its greater mineralogical purity and thermal stability. The results indicate potential application of the samples in non-structural ceramic products and demonstrate the economic relevance of mineral exploration in the region.