Thermal behavior, chemical, mineralogical and optical characterization of clays (kaolin) for industrial use as refractory material

Abstract

The kaolin is an important component of a wide variety of industrial products, therefore kaolin samples of region mines Huayacocotla, Veracruz and Alumbres, Hidalgo were collected, these were treated to reduce the size particle employment an agate mortar and part of each one were analyzed using analytical techniques such as: absorption and emission atomic spectroscopy (AEAS), optical microscopy of polarization (OMP); X-rays diffraction (XRD); refractory test under ASTM standard C-24-79 using a pyrometric cone mold designed on ASTM standard C-24 and thermal test at different temperatures up to 1600 °C with heating and cooling rate of 2.5 °C·min-1. Dates from elemental analysis were converted to percentage in oxides form of major elements. The analysis by OMP showed kaolin alteration degree in the region due to minerals such: plagioclase, feldspar and quartz, hydrothermal alteration of epithermal type represented by oxidation, sulfides (pyrite, galena) and association with chlorite. X-ray diffraction allowed determining kaolinite (Al2O3·2SiO2·2H2O) as majority phase in both Huayacocotla and Alumbres; Cristobalite (SiO2) and Mullite (3Al2O3·2SiO2) were observed in both samples at high temperatures. Kaolin softening point was determined in 1300-1600 °C range, and it makes it feasible as refractory material of low and high temperature. Thermo gravimetric analysis showed that Huayacocotla kaolin are most stable than Alumbres. © (2014) Trans Tech Publications, Switzerland.