PURPOSE: To produce a polyfunctional clinker used as an interlayer compound by using inexpensive pitches having high deoiling property among coal, petroleum containing a graphite-based component and selected from carbides evaluated to have no value at the present time.

CONSTITUTION: (1) The subject graphite-based clinker obtained by the following process and its production are claimed. A carbide containing a graphite-based component, iron oxide, limestone, etc., are mixed in an organic mineral soil having calcium silicate as a main component and the mixture is baked at 300-1500°C to accelerate atomic, ionic and molecular bonding to form a graphite- based interlayer compound, which is slowly or rapidly cooled to stabilize the same to obtain the subject graphite-based clinker. (2) Various hardenable clinkers obtained by adding a hardening agent such as gypsum to the above graphite- based clinker and its hardened products. A mixed product of the various hardenable clinker and usual cement and its various hardened products. Further, a mixed product of the various hardenable clinkers and general cement and its various hardened products are included.