Análise experimental do comportamento de materiais cerâmicos refratários reforçados com fibras de aço e sílica da casca do arroz

Abstract

This work was developed with the intention of presenting an alternative to destination of residual ash from power generation from burning rice husk process. We used the silica-rich ash as a partial replacement of clay used for the manufacture of refractory ceramics. The work is justified by transforming an abundant residue in the western region of the state of Rio Grande do Sul in-product, ie "transformation" of ash on silica. Specimens were produced with partial replacement of silica refractory clay for rice husk, the percentages of 10%, 20% and 30% and incorporation of 1% volume of steel fibers. The specimens were molded, pressed uniaxially at 20 MPa, dry environment for 14 days and then in an oven to be fired in an electric kiln to 1300ºC. After firing, were determined and the physical properties of the material through the thermomechanical tests, density of bulk density, apparent porosity, water absorption, linear firing shrinkage, compressive strength, flexural strength at three points and crashworthiness heat. With the addition of refractory materials in the ash reducing the values of apparent porosity and water absorption, reaching a minimum of 3.71% water absorption for mixing with 30% gray occurred. The values obtained for linear shrinkage were close between 10.43% and 11.27%. The bulk density of the material had a shy variation of 2.25 to 2.36 g / cm ³. For mechanical testing samples with addition of 20% gray offered the best performance. In the thermal test mixture that best performance was achieved with addition of 10% gray. It is concluded that the feasibility of using silica from rice husk in the production of refractory ceramic is torn between two directions, ie, mixtures with up to 20% gray gain in strength but lose in thermal shock resistance.