US883595A - Apparatus for obtaining metals and alloys. - Google Patents

Description

N0.'883,595, PATBNTBD MAR. 31, 190s.

' E. VIEL.

.APPARATUS FOR OBTAINING METALS AND ALLOYS.

APPLICATION FILED 00T. 29. 1907'.

being treated, and so forth.

- very linelypulverized condition; the` proporwho have taken up this question have failed UMTED sTATirds PATENT omnes.

inirLiirNviEL, or RENNES, ritmes.

` APPARATUS Fon OBTAINING METALS AND ALLoYs.

No."8s3,595.

speiacanon or Letters Patent.

ratented March 31, 1908.

Original application filed Octoberl, 1996, Serial No3-11,494. Divided and this appiicationvfiled October 29, 1907.

' Serial No. 399,696.

T o all whom fit may concern:

Be it known that l, EMILIEN VIEL', oi" Rennes, France, have invented a new and useful Improvement in .Xpparatus for Obtaining;r Metals and Alloys, which improvement is fully set lforth in the following specification.

This is a division of my application i'iled Oei. si, ieee, serial No. 341,494.

T his invention relates to apparatus for obtainii'ig' metals and alloys and in particular' aluminiun'i, silicon, magnesium chromium, ete, by reduction of their oxids,`

llitherto numerous attempts have been made by. scientists and engineers to reduee in tl-e electric furnace the refractory oxids, such as alumina, silica, magnesia, and chromite, efe., for the purpose of obtainiiipr the correspondingl metals. .'l`hese attempts have not been successful because the inventors to realize the necessary conditions in their processes and their apparatus. The vfirst of these conditions is to raise to the formation tennpcrature, that to say ai'iproximately to the decomposition temperature, all the. compounds of the known i'netals, and at this moment to cause the intervention of a bod)Y i, capable. of absorbing the oxygen, if an oxid is being treated, the clilorin, if a ehlorid is l ln the vmost i lgeneral where oxidsfliave to be treated, the appropriate reducing agentis carbon'. In order to comply with this comlition, it is necessary to have an apparatus permittiner of obtaining a sul'i'ieiei'itly high tenii'ierature.

rl`he second condition is to form beforehand with the rei l ueinpr agent, such as carbon, preferably in the. forni of charcoal, as perfect a mixture as possible, which result may lbe obtained by employing these bodies. in a tions of the mixture should then be such as. are indicated by tlze equations of the chemical reaction, forexa m'ple ln the. thii'l paee care should be taken that when the mixturel has been raised to sueh a temperature that deeimiposition vhas i taken place, the metal liberated should immedia (ely be Conducted from the excessively hot decomposition zone into another relatively .cold mme which is at :i temperature l lower than lhe vohiiili'fcation tenfperature of i the separated metal. For example, lin the case of alumina, which is decomposed by carbon at a temperature of about 30000 centigrade and gives aluminium, thc arrznigenient :must be suchfthat immediately after its separation the aluminium is conducted .into a Zone at a temperature lower than S000 C., above which temperature aluminium volatilizes. In this manner, the combination `of the volatilized metal with oxygen andthe formation of .the oxid is avoided.

Finally the addition of the mixture of; oxid and carbon or other reducing agent should take place progressively, that is to say, almost in a eoi'itinuous manner, and in small quantities, so that it is only necessary immediately to raise to the decomposition temi'ierature oi the oxid small quantities of the mixture which is passing into the excessively hot zone, and to eileet the conduction of ther metal into the cold zone very rapidly.

The process in accordance with the present invention therefore consist-s in subjectingI to the decomposition temperature of the oxid or ofthe compound, and this in a continuous manner, small quantities of the mixture, which is very intimate and appropriately proportioned, of the oxid or the compound with the reducing body, the metal or alloy arising fromv the decomposition being immediately conducted in an appropriate manner into asu'lliciently cold zone, that is to say, a zone at a temperature lower than that of' volatilization of' the metal or of the metals of the separated alloys for the purpose of preventing?r combination with the oxygen of the air.

lin the followingV description, a workinfev furnace which satisfies the conditions enumerated' above, is referred to by Way of example and illustrated in thc accon'ipanyinr drawings, in which Figures l and 2 represent the said furnace in cross-section and in longitudinal section rcsiiectively.

The furnace consists essentially of a fusion chamber or crueible o with carbon walls l) provided with a cover c likewise of carbon, and with a sole d havingr a very steep linclination (say, 250 to 30o) this sole havingr rat its lower extremity a water 'circulation e extending for example over about one-third of the sole.` This chamber ory erucible is surrounded by refractory Walls or coverings of. appropriate thickness, wheh may be confinedin a sheet metal jacket g.

At the lower part of the wall situa-ted at the lowest part of the sole, a tapping hole h of appropriate dimensions is formed, to permit of the dischar e of the metal; there may also be provided a ove this tapping hole a second hole h which is ordinarily stopped'by a plug g of 11efractory-material having a carbon extremity, which hole may be used for `inspection purposes and for cleaning the sole.

Two electrodes i i of circular or rectan ular or other cross-section enter the cham er or crucible horizontally in line one with the other, or inclined, these electrodes passing through appropriateapertures j formed in the walls f, considerable play being left between the walls of these apertures andthe electrodes, the said apertures being covered with a protecting layer k of magnesia. These electrodes't i, a're supported by appropriate bearings or supports l, mounted in slideways in such a manner that the electrodes may be caused to advance or recede by appropriately rotating theendless screws 'm by means of handl wheels a. The object of this arrangement is to permit of a general regulation of the arc, and in particular in accordance with the wear of the electrodes to which the current is conducted and which it leaves at the terminals o o. In the wall opposite the wall in which the tapping hole 'is formed, a charging orifice (1 is provided,

and in continuation of it a conduit r surmounted by a hopper s in which an Archimedean screw p rotates; this screw is operated4 by hand, or controlled mechanically in any appropriate manner when the furnace acts with a continuous feed. In the median plane perpendicular to the vertical 'plane passing through the electrodes Aand above the carbon cover c, two inclined and symmetrical electromagnets t are jointed on legs u which rest upon projecting bearings on the supports Z. These two electromagnets which may be fed with current in parallel with that of the electrodes, or from an independent source, are wound in such a manner that both of them exert a repelling effect upon the arc, so as to blow it and bring it nearer to the sole. As will be understood, the two effects of vthese electromagnets combine themselves in such a manner as to exert a resultant effect, the direction of which may be varied either by acting upon the inclination ofv one of the electromagnets or of .both at once, or by placing a greater or smaller number of ampere turns in circuit in one of the-electromagnets by means of an appropriate commutator. In this manner it is possible to direct the blown arc for the purpose of locating it in a predetermined zone of the sole, which zone should always be com-- YWised between the points y marked on the drawing', that is to say, outside the cold rione, which is situated above the water circulation e.

The' reduction process in accordance with this invention is then carried out with this special furnace in the following mannen- The hopper g is charged with the appropriately roportioned and pulverized mixture of car onand oxids or compounds to be reduced, and the said mixture is charged continuously or in small quantities on t'o the sole by rotating the screw p. The mixture falls upon the inclined sole at its upper extremity,

and at once reaches the zone of the blown arc the temperature of which may be taken as about- 30000 C. Under the infiuence of this high temperature, the oXid fuses and decomis advisable to preliminarily heat the furnace until the desired temperature is obtained.

During the iirst operation the liberated metal may combine with the carbon of the sole in such a manner as to form a refractory carbid sole. v

lt will be understood that by means of the furnace which has been described, it is possible to realize the conditions of the process because a continuous or almost continuous admission of the mixture may be obtained, and owing to the'very vigorous blowing of the are by means of exceedingly powerful electromagnets, it may be concentrated in a given zone as close to the sole as desired and a very high temperature obtained, and further that owing to the inclination ofthe sole the metal when once it has been-separated immediately passes away from the exceedingly hot zone and reaches another relatively cold zone which is obtained as has been indicated by coolingvby a water circulation. As stated above, this process and this apparatus permit of reducing not only alumina, but also ehromite, magnesia and silica. In this latter case, the o )eration takes place more readily because the volatilization temperature of silicon is 1650O C., that is to say, much higher than that of aluminium, and the difference betweenthe volatilization temperature of silicon and the decomposition tcmperature (25000 C.) of silica is much less.`

With this' apparatus it is also possible to treat silicates or analogous compounds in order to obtain compounds or alloys, such as Silico-aluminium, ferro-chromium, etc. In order to obtain pure aluminium and silicon from Silico-aluminium, it is necessary to heat the Silico-aluminium to 7 00O upon the sole of a reverberatory furnace; the aluminium separates and the silicon remains as residue.

The aluminium thus formed still contains 3% of silicon; in order to obtain it pure, the silicon is burned like carbon ina Bessemerretort.

The process herein described forms the subject-matter of the description and claims of my original, application, Sr. No. 341,494, filed Oct. 31, 1906, and is not herein claimed.

What i'sclaimed is: y

In a furnace of the character described, the combination of a crucible having a steeply inclined sole down which the ore charge moves by gravity, oppositely disposed and adjustable electrodes mounted above said sole and in line ofthe moving ore charge,

hinge-su' ported electromagnets havin the axes of t eir coils in planes at right ang es to the vertical plane assing throughzsaid electrodes andadapted), when energized, to blow thearc towards the sole of the furnace, and.

'means for cooling the sole beyond the heated zone.`

In testimony whereof4 'I have signed this specification inthe presence of two subscrib-

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