Abstract: Vacuum distillation residue oil having a Conradson carbon value of 5 to 40% and a specific gravity of 0.9 to 1.10 is thermally cracked in the presence of iron ore particles in fluidized state in a thermal cracking reactor thereby to produce light oils and cracked gases and to form by-product carbon, which is caused to deposit on the iron ore particles, which are then transferred to and heated at 800.degree. C. to 1200.degree. C. in a reducing furnace to be reduced in a solid state reaction, into sponge iron. Thus, heavy oil is thermally cracked and sponge iron is produced by an economical, integrated process.

Abstract: Pitch is produced continuously by heat treating a heavy hydrocarbon oil at a temperature of 350.degree. to 500.degree. C successively in two or more reactors connected in series, outlet to inlet, recirculating, at the same time, one portion of the liquid output substance from at least one reactor into that reactor, and introducing the output substance (molten pitch) of the final reactor into an after-treatment chamber of duct shape with an inactive atmosphere sealed therewithin thereby to cool the output substance.