Abstract: A process for making a thermal insulation material based on carbon and which includes carbon fibers, suitable for use at temperatures above 1,500° C. The process includes providing carbon fibers with embedded carbon black particles; cutting or milling said carbon fibers to obtain short carbon filaments; preparing a slurry by introducing the short carbon filaments in a liquid phase that includes a binder capable of forming a carbon residue upon pyrolysis under non-oxidizing conditions; casting the slurry into a mold capable of separating the slurry into a wet green body and a liquid phase; and drying and heat treating the wet green body to obtain a thermal insulation material.