US1110208A - Process of electrically treating, melting, and refining metals. - Google Patents

Description

' 0. A. KELLER. PROCESS OF ELEOTRIGALLY TREATING, MELTING, AND REFINING METALS.

APPLICATION FILED AUG. 12, 1902.

Patented Sept. 8, 1914.

' UNITED STATES PATENT OFFICE.

CHARLES ALBERT KELLER, OF PARIS, FRANCE.

PROCESS OF ELECTRICALLY TREATING, MEI-TING, AND REFINING METALS.

Specification of Letters Patent.

Patented Sept. 8,1914.

' Application filed August 12, 1902. Serial No. 119,385.

To all whom it may concern:

Be it known that 1, CHARLES ALBERT KEL- LER, engineer, a citizen of the Republic of.

I ing them at a temperature produced by electric current. 2. The refining of the material or its mixture with others at any moment, 3. The melting and the mixture of metallic waste, particularly of iron and steel, 4. Refining of cast iron in the cupola itself after melting.

The process is based on the employment of an auxiliary chamber, generally a casting ladle, the contents of which can be easily and rapidly" interposed in an electric circuit or be subjected to the action of the latter.

The annexed drawing gives an example of apparatus suitable for carrying out the process.

Figure 1 shows the arrangement when a casting ladle is used, Fig. 2 a vertical section of a cupola as arranged for refining.

In Fig. 1 the casting ladle a rests by means of pivots or trunnions on one end of a "beam Z), the other end of which carries a counterweight c intended for balancing the ladle and its charge; this beam is carried by a truck (1, which can be moved on rails. This arrangement allows of bringing the ladle a to the proximity of a melting furnace to receive the successive tappings or to the proximity of each of a series of furnaces to receive in succession the tappings from such furnaces; it also permits of bringing the same ladle under an apparatus comprising vertical electrodes 0, 6 supported by chain tackle so as to raise or lower them into the ladle for the requirements of the operation as hereinafter described.

In Fig. 2 the-cupola f is provided with a fore-hearth g to receive the molten metal and above which is arranged a group of vertically movable electrodes 6, 6 similar to those previously described.

Taking the first case into account, the ladle a, having a refractory lining, does not form part of the electric circuit; the current .enters and leaves through vertical electrodes 6, 6, arranged above it; these electrodes can be regulated and each constitutes in effect a separate furnace, and in practice I employ more thantwo electrodes for each pole; this permits of always being able to replace an electrode at work without interrupting or disturbing the course of the operation. If only one electrode were provided its removal would cause the breakage of the circuit. On the other hand, if each pole carries a minimum of two electrodes, it will be possible to furnaces of the same battery. This 'arrangement will be particularly useful with the battery of electric furnaces, as the respective output of this kind of apparatus is less than that of blast furnaces or metallurgical melting furnaces of the ordinary kind. After each tapping or set of tappings the molten material contained in the ladle is introduced into the electric circuit and the reheating is effected by a current of suitable strength, regulatable as required. By these means the metal is maintained at the required temperature; the quantity of heat necessary for this purpose will simply compensate that quantlty lost by radiation. The slag which will have probably been tapped with the metal from the furnaces is removed in convenient quantity from the ladle so as not to be superfluously reheated. This removal is effected by simply tilting the ladle. The electric current is interrupted when the ladle has agam to be placed under the openings of the melting furnace or furnaces, to receive a further tapping or tappingsoand the reheating, if required, then takes place as described above. By this process a new method .working is realized; very large casiL-gs can be made with apparatus, the practical butput of which is much less than the weight of these pieces. The temperature of the molten metal can be easily regulated and the metal remaining in the ladle after tapping will not be wasted as often happens, as it can be kept hot until mixed with other tappings; the founder can therefore estimate the amount of metal required for the filling up of large molds without fear of waste resul-ting fro-mtoo high an estimate, which leads him sometimes to under-estimate and I to spoil castings through insuiiiciency of ing from ordinary furnaces as well as for that from electric furnaces.

metal in the ladle.

To refine or make additions to the metal collected inthe ladle it is introduced into the electric circuit, and the removal of slag proceeded with if required, as already described; the current is then regulated so as to considerably reheat the metal to be refined, and the necessary additions are then made to obtain the required quality.

'For example, steel can be manufactured with cast iron from ordinary cupolas by refining this cast-iron by the addition of oxid and, just as in the Martin furnace, one can desulphurize, dephosphorize and deoxidlze. This process therefore permits of transforming anordinary foundry into a steel foundry. This process'c'f refining or mixing can also be employedfor the metal com- The process can also be easily applied to the melting and mixture of steel and iron -waste which it may be required to remelt,

owing to the extreme facility it offers of taking samples, because of the continuous access it permits to the metal in the ladle.

For this purpose a certain quantity of molten metal (iron, steel or cast iron) is firstintroduced into the ladle, and a certaln quantity of ore which covers over the metal. The electric current is then passed into the ladle and the operation having thus commenced, pieces of metal to be remelted and mixed are introduced into the liquid layer. These pieces of metal .could not be v placed in circuit in the empty ladle on acas described. Under these conditions, the

electric working of the apparatus isin no way disturbed and when the melting is complete, the additions can be made and the operation efl'ected according to the usual method of mixing and-refining of metals.

in the metallurgy of iron, the second melting efl'ected as described corresponds to the actual manufacteure in the crucible.

The process above described also permits of transforming the ordinary remelting cupolas into mixed furnaces forobtaining cast iron or steel. As known, some cupolas have a fore-hearth into which the manufactured cast iron arrives; it is this basin which will replace the ladle, for putting this process into practice, which will permit of manufacturing steel with existing apparatus for the manufacture of iron. In this form of application, there is'arranged over the existing or specially constructed fore-hearth g-(as has been described with reference to Fig. 2) a group of vertical electrodes 6, e, which are lowered into it, after receiving the cast iron, and the refining is effected as previously described, after removal ofslag. During tapping the electrodes can be removed or not, and the operation is proceeded with as usual. 7

It is evident that for the refining operations in the case of ladles as well as in cupolas neutral, acid or basic linings are employed, as the case may be. I t

I have in some of the claims referred to iron, by which I desire to be understood either cast iron, wrought or ingot iron or steel.

I claim:

1'. The process of electrically treating, melting and refining metals, consisting in moving a suitable receptacle to two or more furnaces and collecting the products of metallurgical operations in' said receptacle, lowering electrodes into the collected products while in a state of fusion, and subjecting the said products to the action of an electric current of sufficient strength to further heat and refine them.

2.'In the treatment of steel, the process of mixing the products from a number of furnaces, which consistsin introducing them in a molten conditiorT into a single receptacle, and maintaining the mass molten in said receptacle by heat from an electric current, removing portions only of the composite molten contents of the. receptacle without entirely emptying the same, and successively replenishing the receptacle with fresh additions. I

' 3. In the treatment of steel, the process which consists in introducing the steel in a molten condition into areceptacle, and main taining it molten in said receptacle by the heat from an electric current, said process being carried on without the use of a flame or other oxidizing method of heating, whereby desulphuration and conservation of the oxidizable additions are favored.

s 4. In the art of converting cast iron or the produced in any ordinary furnace or opera- I the like into high-grade or crucible steel,

the method which consists in transferring steel produced in any ordinary furnace or operation into an electric furnace, With remox al of the superfluous slag,- and finally transforming it in said electric furnace into the desired product.

6. In the art of electrically treating, melt-' ing or refining metals, the method which consists in moving a receptacle to an apparatus supplying molten metal, charging metal into said receptacle, moving the charged receptacle into proximity to electrodes, and adjusting said electrodes ande stablishing an electric current of suflicient strength through the charge, thereby heating it to the desired temperature.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

CHARLES ALBERT KELLER. Witnesses:

JULIAN CAVERUE, PAUL BACARD.

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