Patent GB-190610396-A (GB)
Title: An Improved Process for the Production of Steel, and an Electric Furnace for Carrying out the said Process.
Inventor: GIN GUSTAVE
Filed: 1906-05-03
Granted: 1907-05-02
Abstract: 10,396. Gin, G. May 3, 1905, [date applied for under Patents Act, 1991]. Electric furnaces.-In an electrode furnace for the continuous manufacture of steel from solid or molten pig-iron, scrap iron, or steel in a more or less finished state, the material treated passes successively through three chambers 1, 2, 3, in which, respectively, the operations of fusion and oxidation of impurities, reduction and carburization, and regulation of the final composition are effected. The chambers contain vertically-adjustable carbon electrodes dipping in the slag, which acts as a heating resistance. The oxidizing-chamber 1 receives the whole current, while the reducing and finishing chambers 2, 3 are connected in parallel. Initially, arcs are struck between the electrodes and scrap iron or molten iron, which is introduced by an orifice A into the chambers 1, 2, 3 and communicating passages B. The furnace lining is of chrome ironstone or other neutral substance where in contact with the slag, the portion of the oxidizing-chamber 1 which contains the metal being basic or acidic according to whether phosphorus is present or absent. In the reducing and finishing chambers 2, 3, magnesia is preferably employed for the bed and parts not touched by slag. In the oxidizing-chamber, the bath consists of ore or slag rich in iron oxide, lime being added when phosphorus is present. The baths of the other chambers are neutral and only slightly reducible ; calcium or magnesium aluminate, obtained by heating bauxite with limestone or dolomite, may be used, and calcium fluoride may also be added. In the reducing-chamber 2, coke or highly carbonized iron is added, iron specially smelted with excess of carbon in an electric furnace being suitable. The regulating of the carburization and the addition of suitable fluxes take place in the third chamber, from which samples can be taken. Oxidation does not occur in the last two chambers, rendering unnecessary the addition of iron containing manganese or silicon. The slag also yields a small quantity of aluminium which combines with any oxygen present. Charging is effected through openings C, and the metal is tapped through a hole D at a certain height above the bed. When the metal is being tapped, the electrodes of chamber 3 are lowered and those of chamber 1 are raised, to maintain the level of metal over the tap-hole ; afterwards, the electrodes in chamber 3 are raised and those of chamber 1 are lowered, so that the carburized steel passes into chamber 3 and the oxidized metal into chamber 2. Pig iron is then introduced into chamber 1 and the electrodes are raised. The Specification in the original form as published under the Act of 1901 describes a furnace which is mounted to be tilted on rollers for discharging the finished steel or the slag, the orifices of the communicating passages being arranged so that no metal passes from one chamber to the next during tapping, while the chambers are in communication when the furnace is upright. A bar of iron is placed in the passage from the first to the second chamber to check any flow of impure metal except when a difference of level occurs. This bar melts gradually and is replaced when necessary. This subject-matter does not appear in the Complete Specification as accepted.