بررسي رفتار حرارتي آرژيليت مصرفي در صنعت نسوز

Investigation of thermal behavior of argillite used in refractory industry

In this project, the argillite was examined to determine its thermal behavior for production of fire-bricks. Some samples were burned at temperatures of 1100, 1200 and 1300 °C for 4 hours. The porosity and density of the samples was determined after burning. The chemical and mineralogical compositions of the raw and burned material were determined by using XRD, which the constituent minerals of the raw material were diaspore, boehmite, kaolinite and anatase (Ti02). The burned argillite consisted of mullite, silica, corundum and rutile. Ti02 undergoes a phase transition when heated and expands at high temperatures which may lead to cracks in the fired material. According to the above data, the high porosity of argillite at 1300 °C can be the result of cracks made by expansion of Ti02 or be the result of exit of lattice water of diaspore, boehmite and kaolinite minerals. The presence of about 3 % of Ti02 in refractory soil increases the total and average porosity.