Thermodynamics of Impurities in Pure Iron Obtained by Hydrogen Reduction

Abstract

Hydrogen itself is not a primary energy and needs an energy for its production, which means that CO2 will be exhausted during the production process, more or less. However, when a Green Hydrogen can be produced, it is a best way to use the hydrogen instead of carbon.In this study, two kinds of iron ore were reduced and melted both under hydrogen and carbon atmosphere. The obtained iron metal under hydrogen atmosphere was quite pure one. The impurities in the metal were chemically and thermodynamically analyzed. The characteristics and benefits of hydrogen reduction were discussed in comparison with the carbon reduction.The content of silicon in the metal under hydrogen atmosphere was one tenth to the iron obtained by carbon reduction. Manganese was about one third to one tenth against the carbon reduction. However, phosphorus in the hydrogen reduction was almost the same level to the carbon reduction. Sulfur content became half in the hydrogen reduction. Moreover, the content of hydrogen in the metal was the same level between the hydrogen reduction and the carbon reduction. It was found that the rate of hydrogen evolution from a molten metal during solidification was fast significantly. The activities of elements in the metal were calculated through the thermochemical data, and the relationships among those elements were elucidated.From the thermodynamic analysis, a high oxygen activity in the metal obtained under hydrogen atmosphere caused to a low content of impurities and high activity of oxides related.

Water Gas Shift Reaction and Effect of Gasification Reaction in Packed-bed under Heating-up Condition

“…(8) The amount of WGSR occurring with gasification reaction was about 1.5 times larger than that of single WGSR. graphite (mol/s/cm 3 -bed) R W : Rate of water gas reaction I (mol/s/cm 3 -bed) R WC : Rate of water gas reaction I of coke (mol/s/cm 3bed) R WG : Rate of water gas reaction I of graphite (mol/s/ cm 3 -bed) R W2 : Rate of water gas reaction II (mol/s/cm 3 -bed) R W2C : Rate of water gas reaction II of coke (mol/s/cm 3bed) R W2G : Rate of water gas reaction II of graphite (mol/s/ cm 3 -bed) R sh-i : Rate of inverse water gas shift reaction (mol/s/ cm 3…”

“…Kashiwaya 1,3) has shown the benefit of reduction by pure hydrogen, in which the rate of reduction is faster than that of CO reduction and the clean iron can be obtained. Before usage of pure hydrogen, we should understand the reactions in CO-CO 2 -H 2 -H 2 O system.…”

“…) and reduction rate (RDR(g-O/min), Eq. (17)) are obtained from gas flow rates, [CO] in , [CO 2 ] in , [H 2 O] in , [CO] out , [CO 2 ] out , [H 2 O] out in cm3 (STP)/min, where the subscript 'in' means the inlet gas and 'out' means the outlet gas, although the reduction reaction is zero (RDR = 0) in this report.…”

“…Online version in color.) balances are always changed in BF and the WGSR should be considered for the change of the equilibrium condition In this study, equilibrium gas flow rates (cm3 (STP)/min), [H 2 ] e , [H 2 O] e . [CO] e , [CO 2 ] e were obtained by the calculation method shown in APPENDIX.…”

Phosphorus Distribution Behavior of Solid Iron Reduced from Molten Al₂O₃–CaO–Fe_tO–MgO–SiO₂ System at 1623 K

“…Kashiwaya et al reported the behavior of impurities when iron ore was reduced using hydrogen or carbon in the range 1 173-1 373 K as part of direct steelmaking. 9) The iron ore was first reduced below the melting point of iron, and the reduced iron was then melted at 1 873 K in the same crucible without removing the slag. The silicon and manganese contents of the iron reduced using hydrogen were lower than those of the iron reduced using carbon; however, the difference between the phosphorus contents of the iron reduced using hydrogen or carbon was insignificant, indicating that the phosphorus had readily moved to the metal phase during remelting.…”