Estudo da influência da temperatura de sinterização nas propriedades finais da diatomita para aplicação como agente filtrante de líquidos

Abstract

Although the presence of porosity in ceramic materials be generally treated as a defect of the final product in production of structural and dense components, diatomite is a type of porous siliceous ceramic with great commercial importance because it combines technologically interesting properties and characteristics. Its physical and chemical properties, after processing, allow it to be used in various industries as food, beverage, pharmaceutical, textile and cosmetics, acting as filter agents, abrasive, absorbent, insulating, among others. The diatomite is found abundantly in the world and mainly in the northeastern region of Brazil where Rio Grande do Norte is one of the states that holds much of the country’s total reserve. Whereas this material undergoes a number of changes due to heat treatment at high temperatures and its environmentally sound characteristics, also arouse the interest of several researchers in the world, this work aims to investigate the influence of sintering temperature on the important final properties for the use of raw materials as filtration agent. For this work benefited mangue diatomite and another type called "bigbeg" from sedimentary deposits in the state of Rio Grande do Norte were used. Thus, compaction and subsequent sintering was carried out in 3 distinct isotherms in resistive furnace. Dilatometry, X-ray fluorescence, nitrogen BET method, X-ray diffraction and scanning electron microscopy characterizations were made and the results show that diatomite bigbeg has higher quality because has higher silica content (86.14%) and lower impurities content. However, the mangue diatomite is more promising in the use as filter agents because after processing obtain greater porosity, greater water absorption, less apparent specific mass and still present porous microstructure of the initial raw material that promotes greater filtrability.