US705727A - Method of treating metallic oxids in the production of metals and alloys. - Google Patents

Description

No. 705,727. Patented July 29, 1902. F. C. WEBER.

METHOD OF TREATING METALLIC DXIDS IN THE PRODUCTION OF METALS AND ALLOYS.

(Application filed Apr. 15, 1901.)

(No MOdel.)

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UNITED STATES PATENT Grace FREDERICK C. \VEBER, OF CHICAGO, ILLINOIS.

METHOD OF TREATING METALLIC OXlDS IN THE PRODUCTION OF METALS AND ALLOYS.

SPECIFICATION forming part of Letters Patent No. 705,727, dated July 29, 1902.

Application filed April 15, 1901. Serial No. 55,990. (No specimens.)

T0 all whom, it 'ntcty concern:

Be it known that I, FREDERICK O. W EBER, a citizen of the United States, and a resident of Chicago, county of Cook, and State of Illinois, have invented a certain new and useful improvement in Methods of Treating Metallic Oxide in the Production of Metals and Alloys, of which the following is a specification.

The employment of aluminium and the reducing action thereof for the treatment of metallic oxids in the production of metals and alloys has long been known,and various methods of employing aluminium for the purpose stated have been described, some of them a number of years ago, Until quite recently, however, anypractical and successful results have not been derived, owing to the fact that it has been impossible to properly and perfectly control the reaction arising from hindrances and conditions not under the requisite control. One of the first attempts in using aluminium as a reducing agent was by mixing it in a finely-powdered state with a metallic oxid in a crucible and then placing the crucible and its contents in a muffle and subjecting the same to aheat which produced an explosive reaction for the charge in the crucible as soon as the aluminium was melted, with the resultthat the charge, the crucible, and the muffle were generally lost by being scattered and destroyed with the force of the explosion, Another attempt in using aluminium as a reducing agent for metallic oxids Was by preparing a mixture of aluminium fillings and the oxids, which mixture was thrown or deposited upon a bath of molten aluminium contained in a crucible. This method'resulted in an alloy of the aluminium with the metallic oxid employed in the given reaction, and the excess of aluminium was -subsequently removed by placing more of the metallic oxid on the surface of the remelted alloy. Under this method or process there seems to have been no effort made to work by atomic proportions nor to specially prepare the oXids used in any given reaction, so that the resultant product was not perfect in every respect. Still another attempt in using aluminium as the reducing medium for metallic oxids was the employment of such reducing power of aluminium for the production of metallic manganese, and under this method or process the reducing power of aluminium was employed by dissolving manganese oxid in cryolite, and in use the method or process was found to be an effective one. The latest and up to the present time the most effectual method of utilizing the reducing properties of aluminium in operating on metallic oxide is the employment of a method or process in which aluminium and metallic oxide; in the form of a very fine powder have been mixed in atomic proportions and after the mixture has been made to start the reaction by igniting the charge at some one point, generally the surface, by the use of an easily-reducible oxidsuch as, for instance, peroXid-of-barium-the usual practice being to start the ignition by inserting into the peroxid of barium mixture at strip of metallic magnesium ribbon and igniting the metallic magnesium strip or ribbon by means of a common match, and after the reaction has been once started additional mixture-is supplied, making the method orprocess practicallycontinual. This method or process while veryelfective so far as obtaining the benefits of the reducing property of aluminium on the metallic oxide is open to the objection of introducing into the resultant product as an impurity the easily-reducing oxid,and in addition the magnesia formed by the burning of the metallic magnesium strip or ribbon will also be found present in the product as an impurity. These various methods or processes of obtaining the benefits and advantages of the reducing action of aluminium 011 metallic oxids all have a serious defect, which is the entire omission of a special preparation of the oxids, and this lack of preparation will at times cause an explosion of the charge and a consequent eduction of the mixture from the crucible, which sometimes results in injury and loss, and the causes for the explosions may be either from the instantaneous reaction or from the pres" ence of trifle of moisture. The trifle of moisture is due to and derived from the hygroscopic character of some of the oxid usedas, for instance, borontrioxid; but ordina= rily it is due to and derived from the fact that the material is moist when used oractcd upon. There is between the extremes of utilizing finely-powdered aluminium in a crucible heated in a nitride and the igniting of cold and very finely-powdered and at times moist charge a definite mean, which when obtained will result in a method or process by which all the benefits and advantages of aluminium in its reducing action on metallic oxids will be obtained, and the gist of my invention consists in a method or process by which this definite mean between the extremes above named is attained; and the invention consists in the various steps and modes of procedure hereinafter described,and pointed out in the claims.

In carrying out the method or process of my invention a magnesia-lined crucible is employed havinglocated inits bottom a small flat coil of aluminium wire, above which is placed a suiiicient quantity of very finely-powdered oxid by atomic proportions which it is desired to reduce at the time. Asmall piece of tissuepaper is placed above this finelypowdered oxid, and above this paper is placed a helix of larger aluminium wire, which may be as small in amount as five per cent., if so desired, of the weight of aluminium required to reduce the oxid of the charge. A mixture of ordinary granulated aluminium is prepared, of which a quantity amounting to the remaining or balance of ninety-five per cent. for the complete mixture is combined and arranged in such relation to the upper coil of aluminium wire that the wire Will be distributed evenly and uniformly throughout the mixture as a whole. After the mixture so prepared is placed in the crucible and pressed thereinto an electric current of sufficient intensity to heat the upper coil of aluminium wire is utilized, by which the entire charge will be brought to 'a temperature of about 212 Fahrenheit, or over, or to as much higher temperature as may be wanted. This first heat so applied to the upper coil of aluminium wire operates to evolve or drive off all moisture contained in the charge and to prepare the charge properly for the reaction treatment and will require usually about ten minutes for the purpose. The electric current is then turned off from the upper coil of aluminium wire and transferred to the lower coil, and the current for the lower coil should have an intensity sufficient to melt the aluminium. The melted aluminium of the lower coil at once reacts with the finely-powdered oxid or oxids thereon and thereover, with the result that the entire charge is under full reaction, producing in a few moments molten corundum, which makes its appearance on the surface, while a regulus of the metal of the oxid or alloy which is undergoing reaction forms at the bottom of the crucible. This mode of treatment results in a method or process by which all danger of explosion, and consequent injury and loss, is obviated. It enables a cheaper granular aluminium to be employed in place of finely-powdered aluminium. It does not contaminate the reducing oxids that form material, as the electrical heat employed will not result in introducing into the product any impurities and the material need not be reduced to a fine powder before charging.

The method or process of my invention enables the making of a compound molecule requiring more caloric than that furnished by the alumina reaction to be attained, as any deficiency of caloric will be supplied by electrically-heated wire. This extra supply of caloric from the hot wire enables the intensity of the heat of the reaction to be raised by just as much caloric as can be obtained by raising the temperature on the wire to a pointbelow where the wire would melt, and thus bringing on a premature reaction, it being well known that every chemical molecule requires a definite amount and intensity of caloric for its formation. It will be seen that with the method or process of my invention an almost endless number of metals or metal loids, alloys, and compounds can be obtained, as the heat required can be governed to suit the requirements for successful operation on the oxid to be reduced. The reaction can be further enhanced by the employment of a crucible lined with a spun thimble of sheetaluminium. This aluminium thimble is to be figured in the stoicheiometric calculation, and its use enables the construction of anysized crucible-shaped vessel of plain magnesia brick. The thimble when the method or process above set forth is utilized will melt and react chemically with the mixture on the outside or exterior surface of the charge, with the result of lining the vessel or crucible with corundum, which, owing to its extreme infusibility, enables the vessel or crucible to be constructed of lime, which is the best material that can be used by reason of its being the best-known non-conductor of calorie, and a vessel of this character enables the prod uction of a very solid regulus from any of the most refractory metals, such as chromium, uranium, tungsten, and others.

In the drawings, which illustrate a crucible or Vessel adapted for conducting the process and the manner of charging the crucible or vessel in carrying out the process, Figure l is a sectional elevation of the crucible or vessel, showing an outer containing vessel of metal, an inner crucible-shaped lining of lime or graphite, a lining of mineral wool and mag* nesia or mineral wool and finely-powdered lime, with a spun thimble of aluminium against the inner face of the mineral-wool lining, and showing also a coil of aluminium Wire with a finely-powdered oxid, a helix of aluminium wire within the charge of coarser material, and a sheet of tissue-paper between the coil and helix, and showing also sources of energy and connecting-wires for transmitting an electric current to the coil and helix; and Fig. 2, a cross-sectional plan view on line 2 of Fig. 1 looking in the direction of the arrow.

A represents the outer wall or vessel of the crucible; B, thelining oflime or graphite, also of a crucible shape; 0, a lining of mineral Wool and magnesia,or mineral wool and finelypowdered lime, or mineral wool alone; D, a source of energy, such as a dynamo; E, anothersource of energy, such as a dynamo.

a is a coil of aluminium wire located in the bottom of the crucible or Vessel and having its ends in the arrangement shown extended above the top of the crucible or vessel.

1) is a helix of aluminium Wire placed within the vessel above the coil and having its ends extending above the top of the crucible or vessel; c, a spun thimble, of sheet-aluminium, placed in the crucible in contact with the lining of mineral WOOl or mineral wool and a neutral oxid.

01 represents conducting wires from the source of energy D to the ends of the coil of aluminium wire.

6 represents conducting- Wires from the source of energy E to the ends of the helix of aluminium Wire.

fis a sheet of tissue-paper placed between the coil and helix over the finely-powdered oxid for preventing the displacement of the finely-powdered oxid in charging the crucible or vessel with the coarser oxid.

g is the finely-powdered oxid.

h is the coarser oxid, which is to be treated.

The spun thimble of sheet-aluminium c renders it possible to use a material in the form of a thin casing or lining C on the outside of the spun aluminium thimble, which may be mineral Wool alone or mineral mixed with a neutral oxid--that is, an oxid neutral to the charge operated upon-with the result that the reaction causes the aluminium of the thimble to combine with and reduce the thin layer of neutral oxid in the mineral wool, or in the event a neutral oxid is not used the aluminium of the thimble will react with that fractional portion of the charge directly in contact therewith and form corundum, which cools as it is formed and attaches to the lining of the crucible, and thereby prevents the contamination of the product of the charge by the mineral composing the lining of the crucible, by which a clean uncontaminated regulus and its corundum slag is formed. The preparatory heating is not intended to designate a simple drying only, as it combines four separate and distinct objects:

First. The preparatory heating effects the drying, as a matter of course.

Second. The preparatory heating at the temperature of red-hot aluminium, which is short of fusion, renders the boric-acid molecule no longer stable. The water of the boricacid molecule is driven off and the boric acid remains as anhydrous boron tricxid, this as an illustration of breaking up of aqueous molecules by the preparatory heatin This This pre paratory dehydration enables the formation of crystalline molecules where at the lower temperature amorphous molecules only are possible.

Third. The preparatory heating having driven off all hydroscopic and combined Water, the reactions are carried on at the temperature of the alumina reaction and of the alumina reaction plus that of the added caloric, there being no water present to absorb caloric to be rendered latent by the change of state from liquid to gaseous.

Fourth. The preparatory heating and treatment enables the entire charge to be heated to a temperature short of that of the fusingpoint of aluminium by the radiation of heat from the helix for the formation of molecules impossible of forming at the intensity of heat of the alumina reaction alonefor instance, ternary molecules of boron, titanium, and iron or silicon, chromium, and boronWhich molecules are incapable of being formed at a temperature of the alumina reaction alone and are essential to such reactions by en-= abling the heat of the reactions to be as much higheras the caloric added to the entire charge by the hot wire.

What I regard as new, and desire to secure by Letters Patent, is

1. The method of treating metallic oxids with aluminium in the production of metals, metalloids and alloys and their compounds, which consistsin subjecting the entire charge, comprising aluminium in admixture with a metallic oxid reducible by aluminium, to a drying and preparatory treatment by heat, whereby the charge is brought into a condition for reaction by eliminating all the mois ture, rendering the charge wholly anhydrous, and thereafter subjecting the mixture to a temperature sufficient to effect reaction, sub" stantially as described.

2. The method of treating metallic oxids with aluminium in the production of metals and alloys which consists in placing the to-be treated charge, comprising aluminium in ad mixture with a metallic oxid reducible by aluminium, in a crucible, subjecting the same therein to a drying and preparatory treatment by electric heat at the time the reaction is to be undergone, for the preparatory treatment to eliminate moisture, break up the molecules containing Water of crystallization and drive on the water of crystallization and bring the charge into a condition for reaction, then raising the temperature to a degree sufficient to effect reaction and adding to the intensity of the reaction temperature the temperature of the preparatory heating, thereby increasing the effective heat by the added caloric of the preparatory treatment, substantially as de scribed.

8. The method of treating metallic oxids with aluminium in the production of metals and alloys which consists in placing a charge, comprising aluminium in admixture with coarsely powdered metallic oxide. reducible IIO by aluminium, in a crucible, subjecting the chargein the crucible to a drying and preparatory treatment by electric heat for the preparatory treatment to eliminate the moisture, break up the molecules containing Water of crystallization and'drive off the Water of crystallization and bring the charge into a condition for reaction and then igniting the charge by electric heat to cause reaction and have the intensity of the reaction heat increased by the added caloric of the preparatory treatment, substantially as described.

4:. The method of treating metallic oxids with aluminium in the production of metals and alloys which consists in placing the to-betreated charge, comprising aluminium in admixture With a metallic oxid reducible by aluminium,in acrucible,subjecting the charge therein to an electric heat and a preparatory treatment for drying the oxid, breaking up the molecules containing water of crystallization, driving off the Water of crystallization, eliminating all moisture and bringing the charge into a condition for reaction and then igniting the charge by electric heat and increasing the intensity of the heat by the added caloric of the preparatory heat giving an increased heat for the production of chemical compounds, substantially as described.

5. The method of treating metallic oxids With aluminium in the production of metals and alloys and their compounds which consists in placing a quantity of finely-powdered oxid reducible by aluminium in the bottom of a crucible with a small coil of aluminium Wire and passing an electric current through the Wire of sufficient intensity to melt the aluminium wire and produce a reaction with the finely-powdered oxid, substantially as described.

G. The method of treating metallic oxids with aluminium in the production of metals and alloys which consists in placing a charge of finely-powdered oxid reducible by aluminium in the bottom of a crucible With a small coil of aluminium wire, placing the to-betreated charge, comprising aluminium in admixture With a metallic oxid reducible by aluminium, around an upper coil or helix of aluminium Wire, passing an electric current through the upper coil or helix of aluminium Wire to dry and raise the temperature of the charge and add additional caloric to the heat of the reaction and then passing an electric current through the lower coil of sutlicient intensity to melt the coil and produce a reac tion with the finely-powdered oxid for such reaction to transmit reaction to the dried and prepared charge which is to be reduced substantially as described.

FREDERICK C. WEBER.

Witnesses:

SAMUEL W. BANNING, THOMAS E. MCGREG-OR.

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