| 摘要 |
PURPOSE:To desiliconize molten iron effectively without slagging off after desulfurization in the stage of blowing a CaO-base desulfurizing agent and an Fe2O3-base desiliconizing agent successively into the molten iron by specifying the relation between the content of Fe2O3 in the latter and the content of CaO in both. CONSTITUTION:The content of Fe2O3 in a desiliconizing agent is set equal to or smaller than the total sum of the contents of CaO in a desulfurizing agent and the desiliconizing agent. First the powdery desulfurizing agent is blown with an inert gas such as N2 as a carrier gas into molten iron to cause the reaction of the formulaI. The CaO contributing to the reaction is just several % the content of the added CaO and the greater part remains unreacted. As the concn. of the CaO is higher, the CaO is less melted and is sintered and solidified in the state of containing the formed CaS. The powdery siliconizing agent is blown into the molten iron in the same way as mentioned above without slagging off to cause the reaction of the formula II. The formed SiO2 forms slag by reacting with the CaO, but if the above-mentioned desulfurizing slag is sintered and solidified, the reaction progresses slowly, on account of which coupled by restriction of Fe2O3, the occurrence of resulfurization is made more difficult. Thereupon, the desulfurizing agent contg. CaO at a higher concn. is more preferable. |
