抄録
The behavior of oxygen during refining process is most important and fundamental reaction. Many investigations on the oxygen had been studied with the pure system, but investigation on the behavior of the oxygen during refining process of steel had not been studied.
The authors studied on the mechanism of operation of oxygen against the bath during oxidizing period in the acid open-hearth furnace process by the limestone method.
Most of oxygen (about 60-70%) operated for the bath through the oxidizing period were supplied from the additional ore and about 30% oxygen came from atmosphere in the furnace and then small quantity of it were supplied from the iron oxide in the slag.
Therefore it was possible to calculate the slag weight by compositions of slag at the above mentioned times and the amount of additional limestone, and to calculate the iron oxide weight from the slag weight and the concentration of iron oxide in the slag.
Effect of the oxygen from ore were influenced by CaO/SiO2 in the slag. If CaO/SiOSiO2 increased its effect was rapid, and the oxygen from atmosphere was influenced strongly by physical conditions of the slag (for instance, thickness, disturbance of surface etc.) in comparision with chemical composition of it (for instance, FeO and MnO content, CaO/SiOSiO2 etc.). The oxygen supplied from the iron oxide in the slag were influenced by the chemical slag conditions, the amount of additional limestone and the temperature.
Most of oxygen (about 75%) which had been sent into the bath were used for oxidation of carbon and about 20% and 3% of it were used for oxidation of silicon and manganese respectively.
The oxygen from the ore was calculated by the amount of the additional are and its composition, and the oxygen from slag was calculated from variation of the iron oxide weight in the slags and so the remaining oxygen must have come from atmosphere.
The method of calculation of the iron oxide weight in the slag was as follows:
If the slag weight at melt-down, before addition of limestone and in the last stage of oxidizing period respectively was expressed by X, Y, Z and the CaO and MnO concentration in the slag at the abovementioned times expressed by XCaO, YCaO, ZCaO, XMnO, YMno, and ZMnO respectively,
where a= amount of additional limestone.
But the absolute MnO content in the slag had no change through the period of limestone addition.
And then because the absolute CaO content in the slag at melt-down and before addition of limestone was equal.
