Патент USA US2405580код для вставки
Aug. 13, 1946. c. B. JACKSON 2,405,580 METHOD FOR PRODUCING ALKALI METAL OXIDES 'Filed nec. 14, 1940 INVENTOR. CHREY E. JACKSON BY j.’ ¿if ArroR/VEK Patented Aug. 13, 1946 2,405,580 srArEs PATENT OFFICE Carey‘B.: Jackson,„Forest Hills, Pa., assigner to'. Mine Safetyv Appliances Company; Pittsburgh', Pa'. . Application December 14, 1940", Serì'aLNo. 370,159' 10 Claims'. l This invention relates t'o- a methodl of? manu facture of oxides-of metals, and-more particularly, to a method and apparatus- which may be; used to- produce> uniform-ly andf economically- oxides of rn-et'al's;` such asßpotassium orv sodium ora mixture thereof- and the pro'duct of which is especially (Cl. 23-184J 2 , amount oi'> time i's--stilly needed to complete the reaction and it necessitates the use ci` consider aktieI equipment if the product is to be manufac tured" in- commercial quantities; The physical characteristics of the resulting productl of thisgeneral'methodiis dense and hard adaptable as ' an air purifying' and oxygen'> evolv and unsuitable for' use in respiratory apparatus ing compound; , and no treatment hasbeen found which will make _One of’ the methods heretofore available for the-product ofr ay nat-ure that makes it suitable for oxidizing these-alkali metals to- a high exi-destato- 10 this' purpose. In somel instances, the product andv which method has had some> commercial formed is so'lz‘ardv as to dissolve only slowly in value- consists of vatw'o‘-step or two-stage methodv Water, An air purifying composition,` in order't'o of procedurea In this method, the pure metal i’s be useful iny respiratory-»apparatus must _be-‘of a oxidized iïrst-to a composition- approximatingxthe porous-'nature or have such characteristics that it metal monoxide and' this is accomplished bysub is instantly'reactive with respiredY air by being jecting the surface- of the-pure molten metalto penetratie by 'carbon dioxide and Water to absorb ani oxidizing atmosphere; The oxygen content carbon dioxide and to»y evolve oxygenV to" replace of the ñuid or atmosphere supplied- is limited to to somev extent the; oxygen consumed. less'than l0v per 'cent-because any-'greater amount The-principal- object voi‘this inventionl is to pro Yvoul'd produce an explosive> condition due tothe 20 vide a-'method--off forming' an oxide of a metal' mass' involved the vapori pressure of the and'ì an apparatusA for performing the method metall. The reaction itself> is sufficiently ex' which is continuous, simple in operation, >inex othermic to carry- the: reaction to'com-pletion- and pensive and rapid in- performance and com this provides a‘source of danger 'if too' much mass mercially practicable and which»v is adaptable to invoved at one time’. The high oxide orvper 2. produce potassium or'sodi-u-m- peroxide or a nii-x oxide, which inV the- case of"potassi`um is potas ture thereof of uniformj composition having defisium tetraoxide (K202i)- and in- the case ofl sodium nite physical>> characteristics rendering the prod if's- sodium- peroxide (Na202), is then` formed from uct adaptable- ast an air purifying- composition, the monoxide' by subjecting the surface of the 'lî'l'ie'f-methodî of' my' invention employs the treat-l molten metal' monoxide to- ox-idizing- iiuid. This ment- off' molten metal- W-_hich is-~ to; be reasonably reaction- is not suñiciently exoth'ermic tor` carry puI-‘e-y or at» leastI not' containing- any impurities on the- reaction and heat must besuppliodvr conwhich would interfere with the process or prevent tinuously. One of the principal di-ñîculties in- this its being used for the purpose intended.- The method is the fact that thereaction takes place molten metal is made-to ñ'ow and in an atomized slowly and it isj diiiicult- to produce a uniform» :‘ state to form- a stream of small or minute par--` product. The motivating' force i'n thisI method ticles and thisv stream is- then subjected to an which would provide uniformity of composition oxidizing atmosphere.. This atomization step .in the-reactive mass is the- capillary movement of' renders-the' me tal- i'ncreasingl‘y reactive and suiiî the> materials and it is apparent that this is slow cien-tly so that a substantially uniform oxidized and'v very difficult tocontrol. Furthermore, this 40, product isy produced- in a rapid and inexpensive method is‘ obviously very expensive to perform in manner. In carrying out themethod for produc' commercial quantities- due to the extensive equip ing alkali peroxides, such as potassium peroxide, ment required' in subjecting the surface-of the a small` stream of' molten metal is directed into materi'alè to Aan voxidizing atmosphereY in the two a flow of iluid'` having an oxygen content of at stages of- the method', and, also, in> performing ' least 1'3- per'cent by volume and preferably‘not the second stage of- the process, a large amount more than 35~ per» cent.' Within these limits of of heat mustV be continuously added tothe massÍ oxygen content, the- method can be carried on to to oxidize' the metal> to the highestV availableV the best advantage relative to _the rate of pro oxide. -iuction, uniformityA and protection of apparatus; In orderV tra-expedite this type -ofoxidi’zing pro» 50 Since the constituency of* ordinary- atmosphere cedure, it has been suggested to supply the-molten`V i's- Withinl the designate-d limits, it is suitable for metal inv theform of'y thin layersI and then subject the practice' of this method. By i-ntroducin'gja these'- layers to the oxidizing atmosphere: Such procedure would, no doubt, improve the uni formity of the composition prepared‘, a great streaml of' themolten'metal into a- iioW of air, fine sphericalï-like‘particles‘ or globules of material are .fortified and suspended in the> flow, and an in 2,405,580 3 stantaneous or at least immediate oxidation oc device in a thin or ñne stream of the molten curs to the metal and this is carried directly and quickly to the highest state of oxidation of the metal. The oxygen content in air is ample to oxidize the metal to the desired state for metals like potassium provided sufñcient volume is sup metal and which when being directed into the will be hereinafter described as atomization. For the purpose of collecting the o-xidized metal, a re plied for mixingkwith the metal .in its atomized ceiving chamber 8 is directly- connected to the fluid ñoW is dispersed so as to form finely divided particles of the molten metal, which operation atomizing device and it has a vent ilu/connected to the atmosphere so that an ordinary atmos state. The fact that the overall reaction is exothermic in these oxidation reactions and to a .pheric condition exists within the chamber and relatively large value, sufûcient heat is available , Va discharge 8b is provided in its lower extremity. to carry the reaction of all> the metal to com pleticn by this continuous process. ,7, . .y i “The op-eration of this device is not described in 'detail nor is the apparatus since it is a device ‘ wellv known inthe art and its principle of opera the atomization of such reactive metal as potas sium and sodium would be dangerous in that the l5 tion is likewise well' known. In the use of such a device for the practice of mixture of the metal with atmosphere would be my method, the molten metal contained in the dangerously explosive and thus> any such hazards i ’ receptacle 5 is drawn into the passage 4 of the would render the method impractical for com housing proper by the flow of oxidizing fluid, in mercial purposes. It has been found that by con trolling the oxygen content Within the limits set 20 troduced into the passage 3, over the opening of the passage 4 or in such relation that the molten forth above, any such dangers are eliminated _metal is discharged from the device in a small sufliciently provided some care is taken in the stream readily dispersable and into the stream practice of the method and it can be and is being of oxidizing iiuid producing the suction and car performed on a commercial scale, with inexpen sive apparatus and at a low cost of operation. 25 rying the formed metal particles or atomized stream of metal into the »receiving chamber 8. In order to prevent the oxide from becoming The metalparticles are intimately mixed with hard and of a high density, it is cooled quickly the oxidizing fluid and because of this and the by the flow of air and reduced below the fusion molten state of the metal as well as the heat temperature of the oxide. Ordinarily, atomlzed molten metal when oxidized appears to burst 30 evolved, an instant reaction oi the metal and the iiuid is caused to oxidize the metal completely open or explode .the spherical shape or globule to its highest state. No means or medium is re type of particles, and when cooled it reassurnes quired to initiate the reaction, since the molten this globule shape due to the surface tension of metal Vparticles in the oxidizing i‘luid flow are in the material. This immediate cooling of the re acted material appears to Vcause it to remain in 35 stantaneously reactive. The heat evolved also accelerates the reaction and the excess of oxygen the bursted condition,rit being what might be present causes the oxidation to be rapidly carried termed frozen in this condition, and this physi to completion. , y _ cal condition is of an aborescent, or fluffy, nature In employing this process in a commercial in structure and because of this property is espe It was thought that any method based upo ` For the purpose of aiding in giving a full and complete description of the method, an appara mannerto produce potassium tetra-oxide, it be ing understood that any reference to peroxide is to be-construed to mean the highest state of ox tus is illustrated anddescribed which has been used for producing potassium tetra-oxide in com mercial quantities. Referring to the drawing, the use, the oxidizing ñuid flow is produced by con necting thepassage 3 o-f the housing to a source cially adaptable for respiration apparatus. 40 apparatus is simply a iluid spray device such as is used to apply paints or other coating on to surfaces and which has been found to be adapt able to discharge a thin or ñne stream o_f metal, idation attainable and suitable» for commercial ` ot ordinaryv atmosphere or airat a'suiiiciently high pressure. In one instance, which has proven to be a commercial application, the air is at about 20 pounds pressure and at a temperature of about this being controlled by an adiustment which 50 75° C. YThe potassium metal is heated to a molten state and maintained in this state during the forms a part of the device. The stream is diverted performance of the method and is preferably at into an air flow which effects an atomization of the metal, _ The device is made of a metal material which is not affected by the temperatures involved in > this method and comprises a housing I having a passage 3 and a passage 4. These passages are connected to suitable tubes, which in turn are connected to a source of oxidizing iluid and to the molten metal, respectively. A vented re ceptacle 5 contains the molten metal and a tube 4a connected to the passage 4 is inserted there in. An opening ‘I is provided in the housing for a temperature several degrees aboveits melting point. In> any event, the temperature should be such that a slight reduction would not cause a solidiñcation or Aany thickening of the molten metal and prevent its being readily and efficiently atomized or discharged in a stream atomized by impingement against a stream of air. For some purposes, it maybe advisable to provide some form of an'inert atmosphere over the surface ofthe metal contained in the receptacle 5 in order to prevent any contamination of the metal before it is introduced into the atomizing device. the passage 4, while Van opening E Which is aligned By heating the compressed air to a tempera With the opening 1 isprovided for the passage 3. ture of >about 75°C., the metal within the hous The oxidizing :duid under pressure is intro ing I, or specifically within the passage 4, is main» duced into the housing through the passage and tained in a molten state while passing through completely encircles the passage 4 containing the. the device. However, this function of the air molten metal and by being discharged at a rela-Y tively high velocity at the opening-5 and over. 70 more or less ancillary because in using air for the practice of my method the oxygen of the airis the opening 1 is effective tol draw the molten the source supplied for oxidizing lthe potassium. metal up into the passage and against a needle While the nitrogen of the air, inert to potassiumV adjustment 9. This adjustment controls the dis or the formed oxide, cools the peroxide in a pref charge of the metal particles from the device and by such the metal is discharged from the scribedmanner. ` 2,405,580 8 supplied is for the purpose of keeping the metal an amount such as to' provide an excess of OXY gen `over that theoretically necessary forA >said oxidation and such, relative to its temperature, in a molten state at the time of discharge into the stream of oxidlizing iiuid. The heat in the molten as to quench the oxideV below its melting point the Vheat evolved bythe reaction accelerates the Ul substantially as rapidly as it is formed, and thereby-producing the peroxide in a iiuiiy and metal is adequate to initiate the-oxidation and rate." ' . » ' . ‘ - In> all cases of application of my method, the uniformly oxidized form of low apparent density chemical properties of the selected metal‘must be considered in adapting my ìnventionto the metal. The properties of the metal upon' which> the method depends are'known and the adaptation of and of high reactivity with exhaled air. ' ` 4. A method according to claim 3, said atmos->-phere being air. " " " V ' » 5. That method of making alkali' metal per' oxide which comprises atomizing molten alkali those skilled in the art. By proper control of the metal at a temperature above but close to its dow of the molten metal and the oxidizing fluid, melting point into a current of air heated to a the`desir'ed oxidation product can be produced; 15 temperature -to maintain the metal particles molten and'thereby rapidlyv oxidizing the metal However, the metal to be oxidized must be such my method to the selected metal can be made by that it can be atomized in a molten state and in-V particles to peroxide, and supplying said current termixed in 'an oxidizing iiowand which by atom of air in an amount such as to provide an excess ization' becomes suiliciently reactive within the apparent limits of the invention to form the de sired oxidation product. ' . ‘ of oxygen over that-theoretically necessary for said oxidation and such, relative to its tempera ture, as to quench the oxide below- its melting ` One of the conditions that appears to lessen point substantially as rapidly as it is formed, and the hazards that exist in treating the highly re therebyproducing the peroxide in a iluiïy and active alkali metals is the vacuum that is utilized uniformly oxidized form of low apparent density in atomizing the molten metal. It is apparent 25 and of high reactivity with exhaled air. ' that if a positive pressure sufficient to move the 6. 'A method of making potassium tetroxide metal to the point of discharge and then dis according to claim 5, said metal being potassium, charge it at a sufliciently high velocity is applied and the potassium and air being heated to about tothe >metal and the metal under pressure in ’75° C. troduced into a iiow of oxidizing ñuid that'some 7. That method ofv making alkali metal per conditions might be created for certain metals oxide- which comprises providing a body of at which would result in avery hazardous condition' least one metal of the group consisting of sodium of operation. Consequently, this method of dis and potassium in the molten state, continuously charge of the metal is preferred although it is atomizing the molten metal with a stream of gas' apparent that it is not indispensable in the prac 35 under pressure and containing from about 13 to tice of the method. This vacuum also eliminates about 35 per cent of oxygen and substantially all of the remainder inert to said metal, said gas being heated to a temperature to maintain said any premature firing or ignition of _the metal. .~'It'is `intended that this detailed ‘description of my method vas speciñcally‘applied to the oxi metal molten, and regulating said stream to pro dation of alkali metals, and particularly of po 40 vide an excess of oxygen over that theoretically tassium metal, discloses the principle involved necessary to convert said metal to the~ peroxide and the exemplary ' vapparatus by which- the methody can be carried on satisfactorily are what state and such, relative to its temperature, as to I now consider to be the best application lof 'my invention, but it is intended that the invention beV . stantially as rapidly as it is formed, and there by producing the peroxide in a fluffy and uni limited only by the scope of the appended ~claims._ formly oxidized form of low apparent density and ofhigh reactivity with exhaled air. quench the peroxide-below its melting point sub ' I claim: '1. That method of :making alkali metal ox-l 8. A method according'to claim 7, said metal being postassium and said peroxide being po . .ide which comprises spraying'molten alkali metal into a current of an "atmosphere containing oxy- i gen and a gas inert to’said metal and thereby tassium tetroxide. - - » - Y 9. A method according to claim 7, said metal oxidizing the metal rapidly, and supplying said atmosphere in an amount such as' to'provide an excess of oxygen over that theoretically neces sary -for 'said oxidation and such, relative to its" being potassium, said peroxide Vbeing potassium tetroxide, and said current of air being supplied in an amount such as to provide from about `5 „ to about l5 times the amount of oxygen theo retically necessary for oxidizing the metal. ' temperature, as to quench the' oxide below its melting point substantially as rapidly as it is formed, and thereby producing the oxide in a iiuiîy and uniformly oxidized form of low appar ent density. GO . 10. That method of making peroxide of metal of the group consisting oi sodium and potassium which comprises spraying the molten metal in > 2. A method according to claim l, said atmos a current of an atmosphere of gas inert to the metal and containing oxygen into a chamber phere being heated prior to contact with said heated only by the heat liberated therefrom, sprayed metal to a temperature to maintain said alkali metal molten during oxidation. ' 3. That method- of making alkali metal perox-~' ide which comprises atomizing molten alkali metal into a current of an 4atmosphere contain ing about 13 to about 35 per >cent of oxygen and a gas inert to said metal and heated tov a tem- perature to maintain said metal molten and thereby oxidizingthe particlesof'metal rapidly to peroxide, and supplying said atmosphere in supplying said atmosphere in an amount such as to provide oxygen in excess of that necessary for - said oxidation and such, relative to its temper ature, as to quenchv the peroxide formed below its melting point substantially as rapidly as it is formed, and thereby producing said oxide in a highly porous andA reactive form of low appar ent density. ` , _ . . CAREY B. JACKSON.