Embodiments of a method for increasing the lifetime of a casting slurry are described. One feature of the disclosed embodiments comprises processing refractory materials that are used to form casting slurries to provide a substantial increase in slurry lifetime for slurries made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder. Without limiting the invention to a theory of operation, processing is continued for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at a hydration level which provides an increased slurry lifetime relative to the same material without processing according to the disclosed embodiments.