US1860524A - Manufacture of lead and zinc alloys - Google Patents

Description

Patented May'gl, 1932 7 UNITED STATES PATENT OFFICE JESSE OATMAN BETTERTON, 01? OMAHA, NEBRASKA, ASSIGNOR TO AMERICAN SMELT ING AND REFINING COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY No Drawing. Application filed November This invention relates to aprocess of forming alloys, and more particularly to a process of forming alloys of lead, zinc, magnesium and the alkaline earth metals in which any 5 or all of the above metals are present in any the alkaline earth metals or combinations thereof which is carried out at sufficiently low temperatures to permit the use of standard apparatus.

In accordance with the invention a reagent is added to a bath of lead or zinc under a 'the broad spirit and scope of the invention. "In the following description and in the claims the various steps in the process and the details comprising the invention will be chloride cover slag under such conditions that the lead or zinc forms an alloy with the metal of the reagent or reacts with a metal of the slag which is thrown into the bath by means of the reagent. The slag in the above reaction so'that the process may be carried out at a low temperature and with the use of standard apparatus.

- The invention also consists in'certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following descriptionin which a particular commercial embodiment thereof is disclosed. It will be understood, however, that the processes and the steps thereof'may be modified in various respects without departing from identified byspecific names for convenience application as the art will permit.

but they are intended to be as generic in theirmnnraorunn or LEAD AND zmc aLLoYs 1, 1930. Serial N0. 492,640.

In carrying on the process a bathof one alloy metal, for example, lead or zinc is formed to which is added a cover slag of sodium chloride together with calcium chloride or a chloride of the metal or metals which it is desired to alloy with the bath, and which for ease of description will be termed the alloy forming metals. The bath is maintained at a temperature at which the slag is molten and calcium carbide or a carbide of the alloy forming metal is added thereto.

The slag serves to dissolve any oxide coating which may be formed on the carbide whereby it is permitted to come into intimate contact with the bath, and to prevent oxidation of the metals during the ensuing reaction. An alloy is then formed either from the metal of the carbide or from the metals of the slag which is thrown down by reaction with the carbide. The particular metal which is thusv alloyed depends upon the various metalsemployed for the slag and for the carbide and their relative positions in electro-motive series.

For example, in alloying zinc with lead a slag of zinc chloride and sodium chloride would be employed and calcium carbide would be'used as the reagent. The calcium carbide then reacts with the zinc chloride either directly according to Equation (1),

- thus producing metallic zinc which alloys with the lead for the production ofv a leadzinc alloy, or through the formation of an intermediate compound, liberating zinc and forming calcium chloride and free carbon thereby throwing the zinc into the lead and forming a lead-Zinc alloy in accordance with Equations (2). The sodium chloride serves to reduce the melting point of the slag where by the above reactions may be efiiciently carried ou In forming alloys of lead and magnesium,

for example, a magnesiumchloride slagis used in place of the zinc chloride slag above.

mentioned and a corresponding reaction takes with the metals,

place, throwing down the magnesium and producing a magnesium-lead alloy.

The magnesium-lead alloy may also be formed in still another method by using a calcium chloride, sodium chloride slag and introducing the magnesium into the bath as a magnesium carbide. The magnesium carbide will then ,be dissolved in the bath. releasing carbon and magnesium and causing the latter to alloy with the lead.

The slag will be inert to the magnesium inasmuch as magnesium is lower in the electromotive series than calcium.

Alloys of lead with the various alkaline earth metals may be obtained by any of the above methods by substituting the appropriate slags and carbides. Calcium which is high in the electro-motive series is alloyed directly from the carbide with the use of a calcium chloride, sodium chloride cover. The other alkaline earth metals may be alloyed from the carbide thereof provided a cover slag which is inert to those metals is employed or they may be alloyed from a chloride slag containing the metals provide a carbide is employed which stands higher in the electro-motive series than the metal. Thus, barium may be alloyed directly from barium carbide with the use of a slag of calcium chloride and sodium chloride (BaC =Ba+2C) or the barium may be alloyed from a slag of bariumchloride and sodium chloride with the use of calcium carbide as the reagent. (BaCL, CaC CaCl +Ba+2C) Alloys of magnesium and the alkaline earth metals with zinc'may be formed in a c0rresponding manner using a zinc bath and the particular chloride slag and carbide reagent which are adapted to bring about the suitable reaction. It will be noted that the metal of the alloy is obtained from the carbide reagent, unless this reagent is capable of reacting with the slag to release the metal of the,slag. Consequently, when the metal of the carbide is higher in the electro-motive series than the metal of the slag, for example, a calcium carbide reagent and a zinc chloride slag, the carbide metal will react with the chloride and combine with the chlorine therefrom to release the metal of the slag which becomes alloyed with the bath. It is obvious, therefore, that by properly selecting the reagent and the slag any desired alloy of the above mentioned metals may be formed desired proportions.

The slag acts to dissolve any oxide which may be formed onthe surface of the carpresent in substantially any actionis more efiiciently carried out. Furthermore, the presence of the sodium chloride reduces the melting point of the slag to such value that comparatively low temperatures can be employed and standard apparatus can be used without injury.

As a specific example of a manner in which the present process may be carried out, a quantity of lead or zinc may be applied to a standard lead melting kettle, as for'ekample. a kettle having 16 tons capacity and the temperature raised sufliciently to melt the lead or zinc and form a bath. Temperatures of 535 C. to 7 C. are usually suitable for this pur pose. The kettle may, if desired, be covered mechanically for the purpose of conserving heat and for preventing therfinal alloy from coming into. contact with air and suitable stirring means may be incorporated for agitating the bath and forming an intimate mixture of the bath and the reagents.

A dissolving cover slag is then applied to the surface of the bath. -This slag consists of calcium chloride or a chloride of the alloy forming metal or metals, together with so dium chloride. Calcium carbide or a carbide of the alloy forming metal is then added to the bath and rapidly stirred therein.

These carbides pass through the slag before coming into intimate contact with the bath.

Preferably the cover slag is dehydrated before being applied to the bath inasmuch as completely dehydrated chlorides react more efiiciently with the carbides which aresubsequently added to the bath. Dehydration,

may be accomplished by melting the chlorides and heating the same to a temperature of 1200 F. to 1300 F, At this temperature the mass is completely liquefied and a large portion of the water escapes as steam. A quantity of carbide, such as calcium carbide, representing from 5% to 15% of the weight of the fused chlorides is then added and the mixture is stirred by a suitable mixing machine. The carbide then reacts with the water of combination forming acetylene gas which escapes and completes the dehydration.

ing slag is particularly. effective and completely cleans the surface of the carbide particles, whereby a full and complete surface contact is obtained between these particles and the molten bath. Under these conditions the bath will substantially decompose the carbides at the temperature range above men ter thereof. The carbides are then added to this vortex and are rapidly drawn under the surface of the molten'bath, whereby unneces- The action of the above mentioned dissolvsary exposure to the air is avoided and their tendency to oxidize is materially decreased. After the desired alloy has been formed, the slag may be removed from the bath in-any suitable manner. This may be accomplished either by skimming the slag or by pumping or tapping the alloy from the kettle. a It is obvious that the percentages of the various metals may be varied within wide limits and that any combination of the above mentioned metals may be formed into an alloy by suitable selection of the metal of the skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. The" process of forming metal alloys having relatively low melting points which comprises forming a bath of one of said metals with a relatively low melting point, applying to said bath a low melting point slag containing a chloride of the other of said metals and "introducing to said bath a reagent capable of reacting with said chloride for releasing said other metal and causing the same to enter said bath and form an alloy therewith.

2. The process of vforming metal alloys having relatively low melting points whichv comprises forming a bath of one of said metals with a relatively low melting point, applying thereto a low melting point slag containing a chloride of the other of said metals and adding to said bath a reagent comprising a metal carbide capable ofreacting with said slag to release the metal thereof and cause the same to enter said bath and alloy therewith. v I

3. The process of forming metal alloys having relatively low melting points which comprises forming a bath of one of said metals with a relatively low melting point,

applying thereto a low melting point slag containing a chloride of the other of said metals and sodium chloride, adding to said bath a reagent comprising a metal carbide capable of reacting with said slag to re ease the metal thereof and cause the same to enter said bath and alloy therewith, said sodium chloride acting to reduce the melting point of the slag whereby the process can be carried on at lower temperatures.

4. The process of forming an alloy of lead with a metal of the group comprising zinc,

magnesium and the alkaline earth metals, which comprises adding to'a bath of lead a slag containing a chloride of the metal to be alloyed therewith and applying to said bath a reagent capable of reacting with said chloride to release said metal and causethesame to ellllter said bath and become alloyed therewit 5. The process of forming an alloy of lead with a metal of the group comprising zinc,

magnesium and the alkaline. earth metals,

which comprises adding to a bath of lead a slag containing a chloride of the metal to be alloyed therewith and applying to said bath a reagent comprising calcium carbide and maintaining said bath at a suitable temperature to permit said carbide to react with said slag, whereby the metal of the slag is released and caused to enter said bath and to alloy therewith.

6. The process of forming an alloy of lead with a metal of the group comprising, zinc,

magnesuim and the alkaline earth metals, which comprises adding to a bath of lead a slag containing a chloride of themetal to be alloyed therewith together with sodium chloride, applying to said bath a reagent capable of reacting with said chloride torelease said metal and cause the same to enter said bath and become alloyed therewith, said sodium chloride serving to reduce the melting point of the slag whereby the process can be carried on at lower temperatures.

7. The processof forming alloys of lead with magnesium, zinc'and the alkaline earth metals which comprises forming a bath of molten lead at a temperature range of substTantially 535 C. to 760 0., adding to the surface of said bath a slag containing a chloride of the metal to be alloyed therewith and applyingcalcium carbide to said bath while maintaining the bath at the above temperature, whereby said calcium carbide reacts with said slag to release the metal therefrom and tocause the same to enter said bath and become alloyed therewith.

8. The process of forming an alloy of lead with magnesium, zinc or the alkaline earth' metals which comprises forming a bath of lead and adding thereto a slag containing the magnesium or alkaline earth metal in the chloride form, together with sodium chloride, maintaining the bath at a temperature at which said slag is molten and adding a reagent to said bath capable of reacting with the metal chloride to release the metal there from, whereby said metal enters said bath and becomes alloyed therewith.

9. The process of forming an alloy of zinc with magnesium or the alkaline earth metals which comprises forming a bath of zinc, adding thereto a slag comprising a chloride of the desired alloy metal, and adding to said bath a reagent capable of reacting with said chloride to release said metal and permit the same to enter said bath and alloy therewith. 10. The process of forming an alloy of zinc with a metal of the group comprising magnesium and the alkaline earth metals, which 5 comprises adding to a bath of zinc a slag containlng a chloride of the metal to be alloyed therewith and applying to said bath a reagent comprising calcium carbide and maintaining said bath at a suitable temperature to permit said carbide to react with said slag,

whereby the metal of the slag is released and caused to enter said bath and to alloy therewith.

11. The process of forming an alloy of zinc with magnesium or the alkaline earth metals which COIIIPHSGS forming a bath of zinc and adding thereto a slag containing magnesium or the alkaline earth metals in the chloride form, together with. sodium chloride, maintaining the bath at a temperature at which said slag is molten, adding a reagent to said bath capable of reacting with the metal chloride to release the metal therefrom, whereby i said metal enters said bath and becomes alloyed therewith. m

12. The process of forming alloys of zinc with magnesium and the alkaline earth metals which comprises forming a bath of molten zinc, addirfg to the surfaceof said ath a slag containing a chloride of the meta to be alloyed therewith and applying calcium carbide to said bath, whereby said calcium carbide reacts with said slag to release the metal therefrom and to cause thesame to enter said bath and become alloyed therewith. In testimony whereof I have hereunto set myhand.

JESSE OATMAN BETTERTON.