US2564037A

US2564037A - Method of removing skulls from metal receptacles

Info

Publication number: US2564037A
Application number: US782532A
Authority: US
Inventors: George V Slottman
Original assignee: Air Reduction Co Inc
Current assignee: Airco Inc
Priority date: 1947-10-28
Filing date: 1947-10-28
Publication date: 1951-08-14
Anticipated expiration: 1968-08-14

Description

Aug. 14, 1951 I 5, v SLQTTMAN 2,564,037

METHOD OF REMOVING SKULLS FROM METAL RECEPTACLES Filed 001,. 28, 1947 ATTORNEYS Patented Aug. 14, 19 51 METHOD OF REMOVING SKULLS FROM METAL RECEPTACLES George V. Slottman, New York, N. Y., assignor to Air Reduction Company, Incorporated, New York, N. Y., a corporation ol' New York Application October 28, 1947, Serial No. 782,532

2 Claims. 1

This invention relates to the treatment of ladles, mixers, and other receptacles employed in the handling of molten metals and particularly to a method of preventing formation of and of removing skulls from such receptacles.

In the production of metals and alloys and especially in the steel industry, receptacles gen-' erally referred to as ladles, mixers and the like are employed in transferring molten metal and in other operations. From each successive charge of molten metal delivered to the receptacle, a portion chills and solidifies upon the bottom and walls. Gradually, accretion df metal forms a so-called skull which eventually reduces substantially the capacity of the receptacle. Where considerable quantities of molten metals are handled, this loss of capacity may reduce seriously the efllciency of operation.

Many attempts have been made heretofore to remove skulls from ladles, etc. The procedure usually involves chipping, which is expensive and often destructive to the lining of the receptacle. Attempts have been made also to employ an oxyacetylene torch or lance to melt and burn the accretions, but the results are not satisfactory. Damage to the lining of the receptacle frequently involves expensive and time-consuming repairs.

It is the object of the invention to provide a method whereby receptacles for molten metal may be so treated periodically as to prevent the formation of or to remove skulls resulting from accretion of solid metal therein.

It is a further object of the invention to provide a method which may be applied to receptacles of a variety of shapes and sizes and without deleterious action upon the lining materials.

Other objects and advantages of the invention will be apparent as it is better understood by reference to the following specification and the accompanying drawing, which illustrates in section a receptacle and the means for eliminating the skull therefrom.

In accordance with the present invention, the skull is eliminated from the receptacle by the application of intensive heat, sufllcient to melt the material forming the skull. The heat is applied by introducing oxygen to molten material, within the ladle, containing oxidizable constituents. It is not necessary that the composition of the skull and of the molten material be the same. Skull formations usually comprise various constituents including metal and slag. The molten material may be a part of the charge which the ladle or other receptacle is handling, or it may be special material introduced for the 2 purpose. Any material having sufiicient quantities of oxidizable constituents and adapted to attain the necessary temperature may be used. All ferrous materials contain silicon, manganese, carbon and iron, which are oxidizable in the presence of oxygen. Molten iron from a blast furnace is ideal for the purpose of the present invention, since it contains high percentages of impurities such as silicon, manganese and carbon. The iron itself is readily oxidizable in the presence of oxygen. Hence, when oxygen is introduced in sufficient quantity into the molten material, a high temperature is developed with the resulting meltin of the skull. The molten contents, at the completion of the operation, may be discharged from the receptacle, leaving it clean and suitable for further use.

Obviously, the method may be practised in such a way as to prevent substantial accretions and the formation of skulls by treating the receptacle after each third or fourth operation, that is, after it has been used in the ordinary manner as a container for molten metal. If, however, a substantial skull has formed, it may be eliminated readily in the manner described.

Referring to the drawing, 5 indicates a ladle of the usual type which consists of a steel shell of sufficient strength to withstand the stresses to which it is subjected. Trunnions 6 permit the ladle to be lifted by a crane or other apparatus adapted to facilitate transportation. A lining I of suitable firebrick or other heat resistant material is disposed within the receptacle. The shape and design of the receptacle may vary, depending upon the particular purpose for which it is intended.

The skull 8 forms, as shown. in the bottom and on the sides of the receptacle 5. If the material is permitted to accumulate, it will eventually fill the receptacle, which thereafter will be useless. Obviously, the formation of the skull reduces the capacity of the receptacle.

To prevent the formation of such a skull or to eliminate it, a mass 9 of molten material containing oxidizable constituents is permitted to remain in the receptacle or is added thereto. Oxygen, from a suitable source, is introduced through a pipe I 0 which may be connected by a hose l I to the source of supply. The oxygen may be substantially pure, that is to say, the oxygen of commerce, but it is not necessarily free from other gases such as nitrogen. Thus, a'mixture of nitrogen and oxygen containing 35% or more of oxygen will serve the purpose of burning combustible elements in the molten mass 9. thus rapidly producing temperatures suflicient to melt the material forming the skull 9.

When the skull has been melted, the molten material may be poured from the receptacle which is then clean and free for further use. The operation as indicated may be repeated at intervals to prevent accretion of material in the receptacle and the formation of a skull.

It is evident that the method as described may be applied easily to ladies and mixers without the necessity of removing them from operation and that receptacles of almost any size or shape are adapted to the treatment. The invention is particularly useful in types of receptacles having relatively small outlets so that the interior thereof is not readily accessible.

Various changes may be made in the procedure as described and in the apparatus employed without departing from the invention or sacrificing the advantages thereof.

Iclaim: i

1. The method of treating receptacles for molten metal to remove accretions of solid materials therein which comprises adding molten pig iron to the receptacle and injecting oxygen into the molten pig iron to increase its temperature and thereby melt the accretions.

2. The method of treating receptacles for 4 molten metals, which receptacles have accretiont of solid materials therein, which comprises introducing a mass of molten material comprising ferrous metal containing oxidizable constituents into the receptacle and injectin oxygen into the molten material to increase the temperature thereof and thereby melt the accretionsfi GEQRGE V. SLO'I'I'MAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 714,565 Dunford Nov. 25, 1902 936,981 Brautigam Oct. 12, 1909 1,484,465 Billings Feb. 19, 1924 1,756,054 Crum Apr. 29, 1930 FOREIGN PATENTS Number Country Date 112,199 Great Britain Jan. 3, 1918 OTHER REFERENCES Mellor: "Modern Inorganic Chemistry," revised edition. 1939, pages 807 and 808. Iongmans, Green and 00., New York.