This paper presents the findings on thermal expansion behavior of slaked lime doped rice husk silica (RHS) refractory monitored between 25 °C and 1500 °C. It also reports the phase transition analysis within the temperature range of 850�1450 °C. A sudden expansion of 0.7 noticed at 220 °C is due to the transformation of α-cristobalite to β-cristobalite. The highest expansion (0.85) reached within the temperature range of 650�850 °C, remains almost constant for the investigated temperature range, and is not high enough to cause macro cracks in the refractory. The phase transition order is similar to those reported for quartzite refractory after 600 °C, though the crystallization temperature is lowered due to the presence of the dopant. Modulus of rupture, apparent porosity, bulk density, refractoriness and reheat change are reported and their results meet with the standards qualifying them for use in coke ovens. © 2013, The Author(s).