The most important function of pre carbonization process is to improve materials density and increase the loading capacity of graphitization furnaces. The complete Pre carbonization system contains preheating section, pre carbonization section, cooling section and exhaust gas treatment system. The maximum temperature can reach 1100℃, it make the coating material and spherical graphite fused together and the coating material formed a shell to wrapping the spherical graphite. Using natural gas for heating, saving energy and reducing consumption, reducing production and tail gas treatment costs. Internal recycling and reuse of gases such as heat flow waste gas, ensuring environmental protection and safety. Adopting continuous production, stable quality.