US1562654A - Method of producing alloys - Google Patents

Description

Patented Nov. 24, 1 925 UNITED sTA as PATENT OFFICE.

; ALADAB racz, or cmvnmmi amen-rs, 01:10.

METHOD OF. PRODUCING ALLOYS.

V w for its general object the provision of a new and improved method of producing alloys especially those wherein the ingredients differ considerably in melting points. From one aspect this invention constitutes an im- 1 provement upon the invention set forth in my copending application filed February 13, l920, Serial No. 358,555, although not restricted to the ingredients therein defined. In that application I have set forth and claimed a method for producing a finegrained, strong alloy of aluminum and silicon containing a larger proportion of silicon than was ever before associated with aluminum in solid solution form. Considering however that the melting point of silicon is about 1400' C. and that of aluminum only about 650 C.,-the alloying of. these sub: stances together offers certain practical difii-. culties which I have avoided by the invention herein described. Furthermore, metallic silicon, although obtainable at the present time at a considerably cheaper rate per pound than aluminum, can be. obtained by means of the process herein described at; at a very low rate, added to which is the fact that my improved process resultsin certain by-products whose value is greatly in excess -.of the ingredients. This process also serves for the ready production of numerous alloys never before available and for the ready reduction of many metals ordinarily very difiicult to obtain in metallic form.

The objects of my invention are the provision of a new and improved process for producing metallic silicon in an alloyed state; with aluminum; the provision of a new method of alloying aluminum with a considerable quantity of silicon at a comparatively low temperature; the provision of a method for utilizing a new and hitherto unused source o'f silicon; the provision of a new and improved method of producing artificial cryolite; the provision of a new and improved method for producing the alloys of action and itself Application filed larch 18, 1920 serial No. ceases.

numerous other metals in conjunction both with aluminum and with other metals; the provision of a new and improved method for producing numerous refractory metals in a pure metallic state; while further objects and advantages of the invention will become apparent as the description proceeds,

For convenience of description "I will die vide the same into four heads, although it will be understood that all of the same are expressions of a single generic idea, said heads being as follows: (1) that wherein the object in view is the'production of an alloy of aluminum and silicon, the latter being produced entirely by reduction at the time; (2) that wherein the object is still the production of an alloy of aluminum and silicon and alpartof the latter is supplied in previously reduced form; (3) thatwherein the method here employed is utilized for the reduction of other metals and their employment either alone or alloyed with aluminum;

(4) that whereinthe base of the alloy is I other than aluminum.

Generically speaking, my invention resides in the reduction by aluminum of a double fluoride of some other metal with an alkali metal-such as sodium, the reaction being er:

formed in the body of a mass of mo ten metal with which the newly reduced metal immediately alloys; oxidation being prevented both by the surrounding body of metal and by the agency of a very fusible flux which is produced as a part'of the reposssses a high value as a by-product. It will be noted in this con nection that under the conditions surrounding this reaction, many metals are replaced by aluminum which are not ordinarily reduced from their oxides by this element.

Firstwconsidering, that specific phase of my invention wherein an alloy of sihcon with aluminunrris desired: I take a quantity of powdered sodium silico-fiuoride (such as is made in rent quantities as a waste. byproduct in t e productionof the fertilizin material known as superphosphate) an mix the same with powdered or blown-metallic aluminum in the proportion of ap proximatel 5 to 1 (564 to 1 08 to exact). I preferably form this, mixture into briquettes or mix the sametogether by means of a suitable binder such as a dilute solution' of sodium silicate, forming the same into bricks,blocks, chunks or pellets of any suitable or convenient size. 'NVhen-these are introduced into a bath of molten alummu the following reaction occurs:

- ing point of silicon, this being doubtless due to the fact that the silicon 1s produced in the atomic or nascent condition. The nonmetallic products of the reaction float upon the metal in the form of a light, clear, readily fusible slag which constitutes a most excellent electrolyte for the tallic aluminum.

The slag and metal are separated in any suitable way, as by" pouring or ladeling, after which the metal is treated with a com pound of fluorine in the reacting condition. In the absence of thisafter treatment, the alloy when cooled segregates into a coarsely crystalline mass having a compartively small tensile strength an elongation.

Inasmuch as the total amount of slag produced by this reaction might easily be much greater than the amount which could be employed as an electrolyte in aluminum production, I prefer in most cases to mix with the ingredients above mentioned a quantity of powdered metallic silicon which when introduced into the bath in company with the remaining ingredients will become quickly absorbed and without the necessity of greatly increasing the temperature of the metal as would otherwise 'be the case. This reaction, therefore, serves not only to incorporate silicon in the bath by reduction production of me .in situ but also serves to facilitate the introduction into the bath of previously reduced silicon, and the latter may be resent in any amount up to about o the total mixture added without necessitating any Inaterialincrease in the bath temperature. Above this amount it becomes necessary to heat the bath to a higher tempera-- ture although I do not exclude the same from my invention. Also when the total amount of added silicon becomes greater than about 30% of the alloy the temperature increases and the yielddecreases. The foregoing constitutes the second aspect ofmy invention. In either case the resulting slag mustbe removed before the fluoride treatment.can be given.

Passing now to the third aspect of my invention suppose it be desired to alloy. the aluminum with some substance other than silicon, I startwith a double fluoride of .sodium and the desired metal; in. other words, substitute for the double fluoride of sodium and silicon the double fluoride of sodium with boron, beryllium, scandium,

columbium"; ytterbium, yttrium, lanthanum,

tltan um, zlrconium, cerium, thorlum, vana dium, niobium, tantalum,-chrom1um, iron,

manganese, cobalt, nickel, copper or uranium, whichever 1s desired to be alloyed with the metal of the bath. Possibly other metals could be employed but these I have tried successfully and while I know that certain others like zinc can be treated in this way I apprehend no practical value outside of the list given. This double fluoride is reduced to powdered form, mixed with aluminum powder in the necessary proportion, agglomerated into lumps, preferably with the use of a binder, and mtroduced into a bath of molten aluminum in the manner heretofore described, whereupon the metal in question becomes reduced and alloyed with the aluminum with the production of the same identical slag as before. In this way it is possible to ;produce an alloy of any complexity desired having aluminum as a base, it being merely necessary to mix the fluorides in the proper proportions.

This reaction may further be utilized for the production of the metals themselves; for example, a" double fluoride of zirconium and sodium is mixed with aluminum and added to a bath of aluminum up to as large a quantity as the bath will accommodate, which depends in large measure upon the fusibility of the resulting alloy. The aluminum is alterwards dissolved out, for example by hydrochloric acid or sodium hydroxide, or other solvent, such a reagent being chosen as will dissolve the one and leave the other. 7 i

The method herein described can also be employed for the introduction into the alloy of other metals in addition to silicon, merely by the addition to the silico fluoride mixture of such other metal or metals in the finely divided form. For example, a quantity of tungsten or molybdenum can be mixed with the sodium silico-fluoride and aluminum, with 01' without an additional quantity of metallic silicon, and in this way be introduced into the bath at a temperature far lower than would serve for the incorporation of these substances by ordinary methods. This method is not confined to the introduction of the metal in connection with the silico-fluoride but maybe employed in connection with any double fluoride one of whose components is replaceable by the reducing metal under the conditions set forth. For example. it is very difiicult under ordinary conditions 'to secure an alloy of aluminum and nickel owing to their widely dissimilar melting points; but by adding to a bath of molten'aluminum a mixture of sodium nickel double fluoride, aluminum powder, and powdered nickel, this absorption and solution takes place at a comparatively low temperature almost quant1tatively, with the greatest of ease and the pro;

duction of a perfectly fusible and easily Separated sla Passing now to the fourth aspect of my invention above enumerated, this process is not limited to the production of alloys hav ing an aluminum base but is equally applicable to the production of alloys of any metal with any other metal, although I conceive it will have its greatest importance in connection with alloys whose ingredients differ greatly in melting point. Thus to alloy zirconium with iron, .the sodium zirconium double fluoride is mixed with aluminum and introduced into a bath of molten iron. If care be taken to briquette or agglutinate the ingredients properly the reaction will be almost perfectly quantitative, substantially all the zirconium being reduced and substantially none of the aluminum being dissolved in the bath. Likewise to alloy molybdenum, tungsten, uranium or vanadium with cast iron or any such metal as can readily be secured in metallic form, or in the form of a ferro-metal, I mix a quantity of the double fluoride of iron and sodium with the requisite amount of aluminum powder and the desired amount of the metal to be incorporated. \Vhen this mixture is introduced into the bath of molten iron the desired effect is produced. I have suggested the iron double fluoride in order to prevent contaminating the alloy with any third metal, although any double fluoride can be used which contains a metal not injurious to the finished product, such as manganese. ployed in the production of any alloy but oii'ers some of its greatest advantages in connection with the preparation of alloys oi the are earth metals which are ordinarily extremely dillicult to produce because of-thc difliculty of their independent reduction which is here entirely avoided.

It will be understood that a great. many modifications and combinations of the steps and procedures above outlined can be made and all such I claim and assert as a part of my invention limiting myself in nowise except as specifically recited in the'claims hereto annexed.

Having thus described my invention, what I claim is: a

1. The process of producing alloys which contains the step of treating with aluminum a double fluoride of sodium with one of the component metals in a molten bath of the other component metal, whereby the aluminum replaces the first named component metal from its compound with the fluorine.

2. The process of producing alloys which This method can be em molten bath of onset the component metals a double fluoridewith an alkali metal of the other component metal mixed with suflicient powdered aluminum to replace such other metal from. the fluoride. x

' The process of reducing metal which resides in the partial reduction by aluminum of adouble fluoride with sodium ofthc metal to be produced, in the body of a mass of molten metal at a ten'iperature at least as high as the melting point of aluminum, whereby the metal is reduced within the body of such molten metal and becomes im mediately alloyed therewith.

4:. The process of producing an alloy of two metals of dissimilar melting points which contains the step .of treating with aluminum a double fluoride of an alkali metal with the less fusible metal in a molten bath of the more fusible metal. a

5; The, process of producing an alloy of two metals of dissimilar melting points which contains-the step of introducing into a'. molten bath of the more fusible metal a double'fluoride with an alkali metal of the less fusible metal 'mixed with sufficient powdered aluminum to replace-such last metalqtrom the fluoride, the temperature of the bath being maintained below the melting point of said last metal.v

6. The process of p'roducin alloys which contains the step of introducing into a molten bath of one of the component metals an intimate mixture of the othen component metal in powdered form together with powdered aluminum and the double fluoride with sodium of a metal which aluminum will replace the aluminum being present in substantially the correct quantity to replace such last mentioned metal molecularly.

v7. The process of producing binary alloys which contains the step of introducing into a molten bath of one ofthe metals an intimate mixture of the other component metal in powdered form with powdered aluu'unum and the double 'I'hioride'with, an alkali metal surface of a molten metal which is capable.

of alloying with such first metal under circumstances which prevent the segregation of the mixture, and finally separating the components of said alloy.

, 9. The process of producing a metal which contains the steps of preparing a double fluoride of such metal with an alkali, mixing such double fluoride intimatelywith a secand in quantity sn cient to replace the first metal, and elevating the temperature of the mixture to the reaction point under fconditions which prevent the access of air;

10. The process of producing an alloy of aluminum and silicon which contains the step of introducing into a bath of molten aluminum an agglomeratedmixture of sodium silico-fluoride and aluminum powder.

11. The process of producing an alloy of aluminum and silicon which contains the step ot'subjectingsodium silico-fluoride to the reduction effect of an excess of metallic aluminum at a temperature above the melting point of aluminum.

12. The process of producing an alloy of aluminum and silicon which contains the step of introducing into a bath of molten aluminum an agglomeratedmixture of so dium silicofluoride, aluminum powder and metallic silicon. I 13. A composition of matter for use in making alloys of aluminum and silicon consisting essentially of sodium fluo-silicate mixed with the amount ofpowdered aluminum requisite to the reduction of the silicon, said mixture agglomerated into-lump form. ll. A composition of matter for use in making alloys of aluminum and silicon consisting essentially of sodium fluo-silicate' mixed with the amount ofpowdered aluminum requisite to thereduction of the sili= con and w1th an addedamount of powdered silicon the whole being agglomerated into lump torm.

15. The process of producing an alloy of a metal whose oxide is refractory which consists in forming a double" fluoride of the same with sodium, pulverizing such fluoride,- mixing the same with the quantity of powdered aluminum necessary to replace the metal first mentioned and adding the Same to a molten bath of the metal with which the first metal is to 'be alloyed.

1.6. In the process of preparing alloys, by adding to a molten bath of one component metal a mixtureof powdered aluminum together wlth a fluoride of the other component metal which aluminum will reduce with in adding to such mixture 2, quantity of' powdered metal and agglomeratiug the whole mass before adding-it to the molten bath. 4 4

18. The process of producin alloys which contains the steps ot' first proc ucing a mixture of fluorides, one of which contains one ot' the ingredients of the alloy and-another of which -is such a fluorideas will combine with aluminum fluoride to produce a't'uslble slag, mcorporatmg therewlth enough pow- 'dcred aluminum to displace such first metal,

mixing therewith a quantity of .powdered metal which 1s-to constitute one of the lngredicnts of the alloy, and adding such mixture to a molten bath of one of the ingredients of the alloy. 4 a

19. The method of producing alloys which consists in fusing the metal of lowestmclting point and introducing therein the other metal in finely divided condition mixed with a double fluoride of an alkali metalnnd some other metal and enough powdered aluminum to replace said last mentioned metal.

20. The method of. reducing the metals whose oxides'are refractory which consists in producing thedouble fluoride of such metal combined with an alkali metal such assodium. mixing such double fluoride with an amount of powdered aluminum sufficient to reduce thc tirst mentioned metal, agglome1'at1ng the mixture into lumps, and adding the same to a bath of molten aluminum. i In testimony whereof, I hereunto alilx my signature.

ALADAR PACV.