SynopsisIn order to collect basic data on the smelting reduction process which consists of blowing powder iron ore and powder coal into molten iron bath with oxygen gas for a partial combustion, the reduction rates of molten iron oxide by the solid carbon or the carbon in molten iron were measured. Molten iron oxide in a steel or an alumina crucible was reduced by a rotating carbon rod. The carbon in molten iron in an alumina crucible was reacted with molten iron oxide which was melted in a steel container beforehand. The reduction rates were calculated from the amount of CO gas evolved. The following results were obtained:(1) The reduction rates o f molten iron oxide by the solid carbon were 0.21 0.82 X 10-~ mol-FeO/cm2s s at 1420 -' 1620°C, and the activation energy of the reaction were 75 and 31 kcal/mol for a steel and an alumina crucibles, respectively.(2) The reduction rates of molten iron oxide by the carbon in molten iron were 1.1-3.3X 10_4 mol-FeO/cm2.s at 142O-'1 620°C, and the activation energy of the reaction was 44 kcal/mol.(3) It was concluded that the reaction rate between the solid iron oxide and the carbon in molten iron was the highest among reactions between the solid or the molten iron oxide and the solid carbon, the carbon in molten iron, CO, or H2 gas based on the results so f ar.

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SynopsisIn the research of a continuous ironmaking process from reduced iron, or pre-reduced iron ore, the reduction rate of iron oxide in molten slag by carbon in molten iron was investigated to know the optimum condition. Mixture consisted of, mainly, 40g master slag and 17.1 g iron oxide, was added onto the molten iron in a graphite crucible, the molten copper in a graphite crucible, or the molten iron in an almina crucible to measure the amount of CO gas evolved in the range of 1320 N 1 620 °C. The following results were obtained:(1) The reduction rate of iron oxide in molten slag by carbon in molten iron, or graphite was proportional to the second power of the iron oxide content in the molten slag except for the starting and the ending periods of the experiment.(2) The rate contant and the apparent activation energy of the reduction of iron oxide in molten slag by carbon in molten iron were obtained from the data of the experiment with a graphite crucible-molten iron and a graphite crucible-molten copper.(3) The maximum rate constant of the reduction of iron oxide in molten slag by carbon in molten iron, or graphite was observed around CaO/Si02 =1.5 of molten slag.

SynopsisThe oxidation rates of the elements in pig iron contained in a graphite crucible were measured by adding Fe203, CaO, Na2CO3 and B203 onto the bath. The effects of temperature, oxygen feeding rate (Fe203 g/5 min), and weight of flux added on the oxidation rates were discussed.Niobium was selectively recovered from pig iron produced from the iron ore found in China. By means of a multi-stage continuous treatment, silicon in the pig iron was first removed by adding an optimum amount of Fe203 as an oxidizer at high temperatures, followed by the selective removal of niobium in excess of manganese by the addition of Fe203 containing CaO or Na2CO3 as a basic flux and by the selective removal of manganese in excess of niobium by the addition of Fe203 containing B203 as an acidic flux.