Characterization of rice straw /ash and using in clay bricks: Fid-Bau Portal

Characterization of rice straw /ash and using in clay bricks

Elwan, M.M. / Attriss, M.S. / Mahmoud, A.A. / Salem, S.A.

The burned rice straw in addition to rice straw were used in this work to prevent the burning of rice straw in the field which affects the purity of air and causes the formation of black clouds in Egypt. So that the aim of the present work was to study the characterization of rice straw ash by using chemical analysis, mineralogical composition as well as the effect of heating on ash in temperatures from 400 deg C up to 1000 deg C. Moreover, the application of the rice straw and its ashes in clay bricks at different clay contents were also investigated. The results indicate that the silica of rice straw is as amorphous at firing temperature 400 deg C up to 600 deg C beside traces of calcite mineral. At 700 deg C calcite was disappeared. By increasing firing temperature from 800 deg C to 900 deg C, the crystallinity increased as well as cristobalite and tridymite were identified. The cristobalite was increased with firing temperature up to 1000 deg C. Applying rice straw and its ash in clay bricks making at different clay contents was investigated at the same firing temperature (900 deg C for 2 hours soaking time). The results revealed that, the crushing strength, bulk density and linear firing shrinkage were decreased with the addition of straw and ash. At the same time, apparent porosity, water absorption as well as loss in weight are increased. Also, the physico-mechanical properties of clay with ash mixture were higher than these of clay with straw, due to the fact that loss in weight of ash was lower than that of straw and the reactivity of silica in the ash, increases the reactivity during firing process.