A influência simultânea do teor de alumina, da porosidade total e da temperatura na condutividade térmica de refratários sílico-aluminosos e aluminosos (The simultaneous influence of alumina content, total porosity and temperature on the thermal conductivity of fireclay and alumina refractories)

Thermal conductivity of high alumina and fireclay refractories with 35.81 wt% ≤ Al 2 O 3 ≤ 93.48 wt% and total porosity between 15% and 81% was evaluated by parallel hot-wire technique. The R ratio (alumina content / total porosity), applied in this work, allowed correlating the thermal conductivity (k) with chemical composition and the physical properties of the evaluated refractories. The least square method was used to generalize the correlation between k and R to larger temperature range. The high correlation obtained (r 2 > 0.93) allows concluding that the use of R ratio is more effective in the thermal conductivity of refractory ceramics than using only the alumina content or the amount of corundum. These relationships obtained in this work are important in the project of furnaces and equipments that uses refractories. They are also suitable data to input computer simulation programs aiming to evaluate the thermomechanical behavior of refractory ceramics.