A process, developed for preparing dense, spherical particles of ThC2 and (Th,U)C2, consists of heating dense sol-gel oxide microspheres with lampblack in a rotating crucible under a flow of argon at 1900 to 2200°C. A precise rotational speed and a special crucible design were necessary to maintain good oxide-to-carbon contact, and to prevent the particles from sintering together and bonding to the crucible wall. The products have a high degree of sphericity and surface smoothness, depending upon the starting sol-gel oxide microspheres. The principal advantages of this process over others currently used are: 1) no elaborate blending techniques of oxide and carbon are required; 2) no densification or spheroidization step is required after the reduction reaction; and 3) the temperature of the process is lower than that of many spheroidization methods.