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Publication numberUS1970136 A
Publication typeGrant
Publication dateAug 14, 1934
Filing dateMar 1, 1932
Priority dateMar 1, 1932
Publication numberUS 1970136 A, US 1970136A, US-A-1970136, US1970136 A, US1970136A
InventorsGummert James S, Hutchinson John E
Original AssigneePennsylvania Salt Mfg Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Protection of molten baths
US 1970136 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Fatented Aug. 14, 1934 warren stares PATENT orrica Hutchinson,

Pittsburgh, Pa.,

assignors to Pennsylvania Salt Manufacturing Company, Pittsburgh, Pa", a corporation oi Pennsylvania No Drawing. Application March l, 1932,

Serial No. 596,148

13 Claims.

This invention relates generally to a method of protecting molten baths from oxidation and also conserving the heat of the bath by covering the surface of the bath with a material con- 5 taining aluminum oxide as its predominant constituent.

Although the invention is useful in protecting metal baths in general, whether the baths are used as galvanizing baths, baths for tempering or heat treatment of articles in general, or for other purposes, it is particularly useful in protecting a spelter bath used in galvanizing from oxidation and also conserving the heat of the oath.

Galvanizing baths of spelter are now either left entirely unprotected or in some cases are covered with a material which provides insufficient protection from oxidation and also allows the loss of a large proportion of heat which may be and it also acts as a heat conserving cover,

thereby reducing the fuel cost. The decreased oxidation of a bath protected by such a covernecessary to remove the oxides formed. The aluminum oxide is preferably added to the bathv in granular or powdered form, the amount being dependent upon the surface area of the bath and the temperature of the bath. The oxide of aluminum is substantially iniusible at the temperature of the galvanizing. bath and, therefore, acts as a better heat insulation than is the case where more easily fusible materials are used.

The invention contemplates not only adding oxide of aluminum to the bath, but extends to the use of materials which will be converted at the temperature of the bath into oxide of aluminum. Thus, hydrate of alumina or other suitable material may be employed. The hydrate of alumina is converted by contact with the molten-metal either partially or wholly intooxide of aluminum which has high heat insulating and oxidation resisting properties. In the converconserved by providing a cover of material in acing reduces the skimming which is ordinarily sion of the hydrate of alumina into the om'de of (C1. it-76.2)

aluminum, it passes through the stage of monohydrate of alumina which has very high heat insulating propertiesf The extent of the conversion will depend upon the particular temperature used, in some cases the conversion be- 69 ing complete while in others the covering layer If a material is used which contains aluminum not in the form of oxide of aluminum, but which is converted after addition to the bath into oxide of aluminum, tlieadded material should contain 75 -a sumcient amount of aluminum so that after it is converted into oxide of aluminum, the oxide of aluminum will constitute the predominant constituent of the covering layer.

We have found from experiments that when a galvanizing bath is protected by a covering of aluminum oxide, a saving of 58% of the fuel may be effected. The saving in fuel is an additional advantage over the saving in 'spelter because of the reduced oxidation of the bath due to the covering layer.

The covering may be put on the top of molten metal in an ingot mold for the purpose of keeping the top hot until the rest of the ingot has solidified.

Although the invention has been describedparticularly in connection with a spelter bath. used for galvanizing, the protective covering containing aluminum oxide as its predominant constituent may be used for protecting other metallic baths, and the invention may be otherwise embodied or practiced within the scope of the :iol-x lowing claims.

We claim:

1. The method of insulating and protecting molten baths from oxidation, which comprises adding to the bath a material which contains free aluminum oxide as its predominant constituent. z

2. The method of insulating and protecting 105 molten metallic baths from oxidation, which comprises adding to the bath a material which contains free aluminum oxide as its predominant constituent.

3. The method of insulatingand protecting 110 molten baths from oxidation, which comprises adding aluminum oxide to the bath.

4. The method of insulating and protecting molten metallic baths from oxidation, which comprises adding to the bath a covering of material containing free aluminum oxide as its predominant constituent and which is substantially infusible at the temperature of the bath.

5. In the method of coating articles by dipping them in a molten bath, the step comprising adding to the bath a material which contains free aluminum oxide as its predominant constituent.

6. In the method of coating articles by dipping them in a molten bath, the step comprising adding to the bath a material which contains free aluminum oxide as its predominant constituent, and which is substantially iniusible at the temperature of the bath.

7. In the method of galvanizing wherein a molten bath of spelter is used, the step comprising covering the surface of the bath with a material which contains free aluminum oxide as its predominant constituent.

8. In the method of galvanizing wherein a molten bath of spelter is used, the step comprising covering the surface of the bath with a material which contains free aluminum oxide as its predominant constituent and which is substantially infusible at the galvanizing temperature of the bath.

9. The method of insulating and protecting molten baths oi. metal from oxidation, which comprises adding to the bath a material which contains hydrate of alumina, and converting the hydrate of alumina into oxide of aluminum, the material added to'the bath containing hydrate of alumina in such amount that the oxide of aluminum formed therefrom constitutes the predominant constituent.

10. The method of insulating and protecting molten baths of metal from oxidation which comprises adding to the bath a material containing hydrate of alumina as its predominant constituent, and converting the hydrate of alumina into the monohydrate of alumina.

11. The method of insulating and protecting molten baths from oxidation, which comprises adding to the bath a material consisting substantially entirely of aluminum oxide.

12. In the method of galvanizing wherein a molten bath. of spelter is used, the step comprising covering the molten bath with a material consisting substantially entirely of aluminum oxide.

13,. The method of insulating and decreasing oxidation of baths which are free from substantial amounts of aluminum, which comprises covering the bath with a material which contains free aluminum oxide at its predominant constituent.

JAR ES S. GUMMERT. JOHN E. HUTCHINSON.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2578977 *Mar 10, 1950Dec 18, 1951Tennessee Coal Iron And RailroMethod and composition for reducing the amount of dross floating on spelter bath
US4033762 *Jun 3, 1976Jul 5, 1977Kozo SatoMethod for preventing oxidation of melted metal
Classifications
U.S. Classification427/433, 75/663, 75/414
International ClassificationC23C2/30
Cooperative ClassificationC23C2/30
European ClassificationC23C2/30