Evaluation of kaolin and bauxite from the Amazonian region addition on mechanical-, physical-, chemical properties and microstructural characterization of red ceramic industry clay of Manaus metropolitan region

Abstract

The present work investigated properties of red ceramic from the Amazonian region after the addition of kaolinand bauxite mixture with 0, 10, 20 and 30%wt. in red ceramic industry clay. Assessed mechanical propertieswere flexural strength and Young's modulus. The assessed physical properties were density and porosity.The microstructural images were assessed with SEM and OM microscopies. The fired samples XRD, the rawmaterials XRF and the XRD were made for chemical composition and present phases assessments. Sampleswere manufactured by uniaxial compaction and fired at 1200°C and 1250°C. Samples without the mixture ofkaolin/bauxite presented higher assessed properties, with approximately 32 MPa of flexural strength and 12%of porosity with 2.3 g/cm³ density. Although the initial idea of this work was to add the mixture of kaolin/bauxite in the red ceramic industry clay for improving assessed properties of red ceramic fired parts, thered ceramic industry clay without addition presented better properties. Such properties were attributed to thehigh aluminous materials content in the raw material. This behaviour is correlated to the fact that bauxitefrom this region presents 55%wt. of iron oxide content with aluminium oxide content lower than 25%wt.Additionally, the assessed properties of the ceramic industry parts fired at 1250°C presented this material aspromising material for ceramic products with a better added value.Keywords: Red Ceramic Industry, Red Ceramic Raw Materials, Characterization