PURPOSE: To separate and recover vanadium and nickel in high efficiency in the regeneration process of heat medium particles used in the thermal cracking of heavy oil, by dissolving the vanadium and nickel deposited to the surface of the particle, and separating and recovering the metal derivatives.

CONSTITUTION: Heat medium particles with deposited vanadium and nickel are extracted through the line 13 at a constant rate, and fed to the regeneration column 14. The separated metal compounds are taken out through the line 19 and fed to a washer 12. After washing, the heat medium particles are recycled to the fluidized bed reactor 2 through a line 22. The washing liquid containing vanadium and nickel is extraceted through the line 23, and fed to the oxidizing tank 24. The oxidized solution is introduced into a pH adjusting vessel 27 through the line 26, in which V2O5 is precipitated by the ammonia introduced through the line 28. After concentration, the solution is introduced into the crystallizer 37 through the line 36, and Ni double salt is crystallized.