| 摘要 |
<p>1365152 Desulphurizing steel; flux compositions FOSECO INTERNATIONAL Ltd 15 June 1972 [16 June 1971 1 Dec 1971] 28241/71 and 55817/71 Addition to 1170168 Headings C7D and C7M In the second (deoxidation and desulphurizing) stage of electric furnace steelmaking there is added to the bath a composition containing by weight the weight of lime being at least twice, and preferably four times the weight of iron oxide, and the latter being insufficient to oxidize completely all the oxidizable material. Magnetite is preferred, but Fe 2 O 3 may also be used, while the oxidizable material may be aluminium, silicon, calcium silicide, ferro-silicon, calciumaluminium, magnesium or mixtures of these. Additional oxidizing agents such as sodium or potassium nitrate, sodium chlorate, manganese dioxide or a perchlorate may also be present, as may be fluorspar, alumina or blast furnace slag. The preferred rate of addition is 20 to 30 kg per tonne of steel, while advantageously at the end of refining the slag is poured into a ladle and the steel then poured through it. An exemplified additive composition consists of, by weight</p> |
