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Abstract

The invention relates to a method and apparatus for desulphurizing iron with minimal slag formation, comprising the steps of melting and heating, to a temperature of about 1400.degree. to 1800.degree. C., a slag having the following chemical composition: 20% max SIO.sub.2 ; 30% max/Al.sub.2 O.sub.3 ; about 5-40% SiO.sub.2 +Al.sub.2 O.sub.3 +TiO.sub.2 combined; 2% max FeO; 1.5% max MnO; about 25-65% CaO+MgO+BaO+Na.sub.2 O+K.sub.2 O; 20% max MgO; 10% max Na.sub.2 O+K.sub.2 O; 60% max CaF.sub.2 ; about 50-85% CaO+MgO+BaO+Na.sub.2 O+K.sub.2 O+CaF.sub.2 ; percentages by weight; where the ratio of the percentage by weight of CaO plus MgO divided by the percentage by weight of SiO.sub.2 plus one-half Al.sub.2 O.sub.3 is at least two and where the ratio of the percentage by weight of Na.sub.2 O plus K.sub.2 O to SiO.sub.2 is no more than one; then mixing the sulphur-containing hot metal with this bath of molten slag so as not to exceed 10 parts molten iron per part slag by weight. The desulphurized molten iron is then drawn from beneath the slag bath. The process may be accomplished using a low shaft furnace according to the present invention comprising a furnace body lined with carbon bricks or carbonaceous, basic or high-alumina refractory bricks and having a discharge pipe extending down to the bottom of the furnace chamber for discharging the desulphurized molten iron from beneath the slag bath.

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First Claim