NOVELTY - The natural gas is subjected to cracking in hydrogen-cooling high pressure DC hollow electrode electric arc furnace with fore-hearth, to prepare hydrogen. The super-high temperature perhydrous tail gas is discharged to rotary kiln, and used as reducing agent. The kiln is used as high-temperature quick reducing furnace to reduce hydrogen in iron ore concentrate particles at high temperature of 1200-1400 degrees C, from molten iron in the electric arc furnace. The prepared hydrogen is used as complementary hydrogen source in the process of reducing sponge iron in electric furnace.    USE - Metallurgical method for quickly reducing hydrogen at high temperature.    ADVANTAGE - The efficiency can be improved. The usage and supply amount of the natural gas, flammable ice gasified gas, coal bed gas or other perhydrous coals can be effectively reduced. The energy consumption can be reduced. The emission of carbon dioxide, sulfur dioxide and nitric oxide can be suppressed.    DETAILED DESCRIPTION - The hydrocarbon or hydrogen is used as direct current (DC) plasma working gas, in the hydrogen-cooling high pressure DC hollow electrode electric arc furnace. The natural gas such as flammable ice gasified gas, coal bed gas or other perhydrous coals, are subjected to cracking and melting so that sponge iron is melted to produce molten iron. The temperature of the tail gas from the rotary kiln is reduced by heat exchange using a tail gas treatment system. The dust is removed by gravity, and the tail gas is filtered by a bag, and carbon black is recovered. The tail gas is subjected to washing, decarbolizing, co-converting and separating, and hydrogen, argon and carbon dioxide are recovered from the tail gas. The tail gas is electrolyzed to prepare hydrogen, using the high-temperature steam generated from the process of heat exchange and temperature reduction of the tail gas of the hydrogen reducing furnace. The prepared hydrogen is used as complementary hydrogen source in the process of reducing sponge. The industrial pure hydrogen that is prepared from recovery process and by electrolysis, is sent into hydrogen cooling system of the hydrogen-cooling high pressure DC hollow electrode electric arc furnace, for cooling the hydrogen and recovering the heat. The hydrogen is prevented-heated and returned into the rotary kiln. INDEPENDENT CLAIMS are included for the following:    (1) hydrogen-cooling high pressure DC hollow electrode electric arc furnace with fore-hearth;    (2) hydrogen rotary kiln;    (3) electrode insulating location current-collection sealing device;    (4) annular oil cylinder lifting device; and    (5) hollow electrode check valve of hydrogen metallurgy smelting and cracking furnace.    DESCRIPTION OF DRAWING(S) - The drawing shows the flowchart illustrating the metallurgical method. (Drawing includes non-English language text)