The newly developed Kaolite 2000-LI castable from Thermal Ceramics meets both the strength and thermal properties needed for high performance linings. The strength-to-density ratio of the Kaolite 2000-LI product is in the range of 11 to 12 psi/pcf. The low k values of Kaolite 2000-LI along with high cold crushing strengths at 450 psi at densities of 38 to 41 pcf translate into superior insulating castable that design engineers can use to substantially strengthen the refractory lining and at the same time provide the thermal efficiency to lower energy costs. Kaolite 2000-LI castable also has low iron oxide content so it can be used in carborizing furnaces or where high concentrations of CO gas are present.