US2489573A

US2489573A - Process of producing chlorates and chlorites of different metals

Info

Publication number: US2489573A
Application number: US647404A
Authority: US
Inventors: Clifford A Hampel
Original assignee: Cardox Corp
Current assignee: Cardox Corp
Priority date: 1946-02-13
Filing date: 1946-02-13
Publication date: 1949-11-29
Anticipated expiration: 1966-11-29

Description

PROCESS OF PRODUCING CHLORATES AND CHIJORITES YOF DIFFERENT METALS Filed Feb.. 15,v 194e Nov. 29, 1949 c. A. HAMPEI. 2,489,573

Patented Nov. 29, 1949 by the absorption of chlorine dioxide by an alkali 5 compound of-"that -metal.- Fori example, -if potassium-chlorate andpotassiunr chlorite -arejao be VnrQducedlil potassiunrl hydroxide, -hasjbeen -em ployed as the-alkaliwcompound; The equation which illustratesD thisfreactiongis:

ThiSprior.knownmroceshw p9SSeSsedevcrel GHLQMQTESLOEDIFFERENTMimes Clifford AxHampeLHarvey, 111;; assign rfyitohQar-w ion-npmiiqnehieagg, Ill-eaepsisetipnpo 5";

which are readily. separahleebyeknewmeommen:f cakfaiilites.ii

Ae.specific.y object .,ofuzthisinyontionaisxatofiproe` vide; a esingle, methodffioi; Sp noducingga..-rch-lorfatc,Lof oneemetalr and iaschlorite v'of aediierent metal., in whichzrione =.or..theeothereisionsiderablyelessf;

solubleeinizthetsametsystemethus Vmaking-theme moreffreadilyeseparablce Another.. speciiic. zobjeet'f.i of,.f.';th'e @invention l=is;. to 5. 10 providefa single processzforzproducing aachlorate i of oneAmetal-.and :aechloritezeofaa ediierent metalp in :which suhstantiallyrall'of ai-'particular-rcationw introduced-into the!` system-,i and whichi ris, cape.. ablefiofttformingtthe chlorate,fgiisautilizeda in. athea inherent disadvantages] For example,A th rre may 15 produotionaof fthechlorate.Ywhi1ef:thechlorite;o1

be numerous commercial and 'economicreaspns why a particular l manufacturerhmayl fwarit. to produce for vuse vor, sale a, chlorateA oflone .metal t and Aa, ychlorte .of I.adifferent metal. Todaccomn plish this desired Y result :'with Ithe prior, knownprocess, it is necessaryto carry out this process twice,V using `one metal alkali ``to -r`produce the desired` chlorateV of that.. metaL in gone .process,;. operation and. using adifferent tmetal?alkali,:in

a differentl metal is formed:

Anotherz.: specific @obj ect of 'the-f: invention; is

to provide@single.fprocesscforethefproduction;of.a@

chlorateon one metal andl'aichlonite ofi.adiierent.,v

20.` metal#:byewhichvvcertain rawz materialsecanzdoe employed for producing onetofethe desired.,f1n-od.;.y uctsfwh'ich: are.differentEmmi-.andless expensive than Vthe Jbase. .wthichiis normally f -ernployedato,,uA produce that product -iThe useiofdessrexpensiye:f.

the second `process `opera-tion.to .prodiice;thedeeVW 25e-materials is made possible-PY: emP-1-051ngthe-.591.113

siredmchlorite of the different meta1.,..,The,refore four products aree` formed,V a1thD11ghonly two really aredesired.'

Another. inherent disadv, antager ofrthepri:or.:`

known processis that itis.extremely difcult and,A 30

oftenimpossibleftoeifect by practicalcommercialmeans ,the separation oi,,the chloratecand- ,the chlorite of thesame metaLi Consequently, after practisingritwo different. :processes to obtainvfour the manufacturer has :been confronted-,With the 1 additional problemV of. separatingr out .theg .two--r desired products.

It. isthefprimaryobject of thisrinvention to provide a. single process. for Athe; production; lofI a C 40if-.KDQWD-1M'HQ1ChlQlftQ chlorate of one metalanda ,ohlorite ora diielentf. metal in which thechlorateand the-chlorite'can-T be selected in accordance Withtheparticulai commercial needs otra given'manuifacturer.-

only.; Begierden; anion@ thefsysierhf meurthe. Laie arid/p produc da following@@eventim-1.:

AS as been@ tedputahoyef andgfas'isnspef @iellyeillusiraed a, it

metal .canI beepmduce .i e .base/,0 fr with.the;present1irmeateniisubsiantiallyetochio:

metrically equivalent quantities vof a chlQrai'e-iV responding-meterme@ .or base,

Afurther primary Object-.refrzthis;;invention isf.. to proifideasingle-.fproeess 10s@v means soie a chlorate of oneimetaland. h1 iteteff-,aediierf A Foreex melee-la chleratebf, the elasscensistneiof, no.

tiuma` orvgmagnesium: A

Byivvayr 2 of exampleg-, it

Qtheri; biecisfaridedyantegsEef,theiinyeniipne Willabecemefeppererlt.during theecquree Qf the-f been In werden@ e ta11,se1ected-fr0ma; iumrsediumflthium; bariimmcalcium, ,.fstxontiummore Iriaigriesi.um.,1:am beeproduced; Vmaacsingle; process .1SililiiltaneQuslyrY use, offt less expensiye mgtegiailsvvihan thef ,e0r 150e with thelproductioni of.afi;vchloriteeof asdiierentx; metal selectedifromthe class;consistingf;Qi/patasv siumesodium.:lithiumcbariumucalcium;;.;stztone t a A gisedesiiied toproducecJ enti-,meint are p rediuedasiixrulteneeuslry andreapbessiumachlratefSimulienewslywmSodiumll:

chlorite, this reaction is illustrated by the following equation:

It will be noted that in this typical reaction substantially all of the potassium appears as the chlorate and substantially all of the sodium appears asthe chlorite. Also, this potassium chlorate and sodium chlorite which are produced can be readily separated by taking advantage of their mutually diierent solubilities in the resultant system. This same condition holds true with the production of any one of the chlorates of the metals enumerated above, simultaneously with the chlorite of Va dierent one of the metals enumerated above. The chlorine dioxide may be absorbed in anlaqueousllmixture of stoichiometric equivalents of two diierent hydroxides of the alkali, the alkaline earth metals and magnesium, such as those mentioned above, until substantial. neutralization is effected. If desired, the chlorine dioxide may be passed first into onev of the` selecte'dalkalis alone until substantially complete neutralization is eiected. Then the other alkali is added and the chlorine dioxide is Acontinued tto be delivered until neutralizationagain occurs. Instead of employing the hydroxides of the metals of the chlorate and chlorite to be formed as the bases involved in Equation b, another compound such as the oxide or carbonate of one of these metals may be employed. vThe term hydroxide as used in the claims embraces the introduction of oxides of the named metals into the system since oxides will inherently. form the hydroxides of the named metals in an aqueous medium.

Instead of employing the alkali compounds such as the oxides, hydroxides or carbonatos as the sources of the metals of both the chlorate and chlorite to be. formed, the discovery has been made that it is possible to employ a salt as the source of the metal oi either the chlorate or the -chlorite being produced. An example of this is given in the following equation:

In this last equation, it will be noted that both stoichiometric,equivalents of the alkali required for the production'of the resultant chlorate and chlorite from chlorine dioxide are furnished by the single base. Additionally, only one of the two stoichiometric equivalents of the metal introduced as the base is used in the formation of the chlorate or chlorite of that metal, while the other stoichiometric equivalent of the metal of the base is used to precipitate the foreign anion introduced asl the salt of the other metal, said precipitated salt'being less soluble than the chlorate and/or chlorite formed and, therefore, being readily separable from the system. Also, the chlorate and chlorite thus produced are readily separable because of their mutually diierent solubilities. Y

From the peculiarities noted above in connection with the process exemplied by Equation c, it will be appreciated that the single base and thesalt that are employed must be so selected that the cation of the base, when combined with the anion of the salt, forms a third compound that is of relatively diierent solubility than the specific chlorateand chloriteselected for production, under the conditions existing in this system. Additionally, when certain chlorates and chlorites .laredesired. to be produced simultaneously,

4 this process exemplied by Equation c offers marked advantages over that set forth in Equation b. For example, when it is desired to produce potassium chlorate and calcium chlorite, the employment of calcium hydroxide and potassium sulfate would entail about one-fourth the present raw. material cost of employing corresponding (stoichiometricallyequivalent) quantities of potassium hydroxide and calcium hydroxide.

To further exemplify this invention, it has been discovered that a chlorate of one metal and a chlorite of a diierent metal can be produced by employing salts of the metals of both the chlorate andthe chlorite desired, in combination with an `alkali of a still different metal.

In this last equation, it will be noted that both stoichiometric equivalents of the alkali required for the production of the resultant chlorate and chlorite from chlorine dioxide'are furnished by the single base, while-'the cation of this alkali is not associated with either the chlorate or the chlorite, but substantially all becomes associated with the anion introduced as the salts of the other two metals. Although the salts of the two metals, which are introducedand subsequently appear as the chlorate and chlorite in the equation presented above, have a common sulfate ion, it is possible to use salts of two different acids, in which case the metal of the alkali introduced will be associated with these two diierent anions.

It further will be noted that in this Equation d, the single base and the salts that are employed must be so selected that the cation of the base, when combined with the anions of the salts, forms a third compound that is of relatively different solubility than the chlorate and the chlorite selected for production, under the conditions existing in this system. Additionally, when certain chlorates and chlorites are desired to be produced simultaneously, the 'process exemplified by Equation d oiers marked advantages over that exemplified by Equation b For example, when it is desired to produce potassium chlorate and sodium chlorite, the employment of calcium hydroxide, potassium sulfate and sodium sulfate would entail about one-half the present raw material cost of employing corresponding (stoichiometrically equivalent) quantities of potassium hydroxide and sodium hydroxide.

It is believed to be desirable at this point to further emphasize the economies that can be effected by means of the processes exemplified by Equations c and d, and the iexibilities of procedure that are made possible by these two methods of operation. For example, if the metal of either the desired chlorate or chlorite is available as a sufficiently inexpensive base, that base can be employed in combination with a metal salt of the other metal involved for producing a chlorate or chlorite `of one of these metals and the chlorite or chlorate of the other one of these metals. On the other hand, when a chlorate of one metal and a chlorite of another metal are desired, and a base of neither one of these metals is available at a suicientlylow cost, it is possible by practising the. process Arepresented by Equation ';l dato' use a low cost third metan lhase-:with a ylow priced salt of. the metalzof eachof" the chlorate` and the chlorite.. desired, im orders to. produce the; chlorate. andthe. chlorite- .of thetwo metals-.- Also, each one of the three modes of operation exemplied by Equations c. andd offers a process whereby the chlorate of one .metal and the chlorite of a diierent metal'may be produced simultaneously with substantially complete. utilization, as a chlorate, of all ofthe metalwhose chlorate is desired and substantially complete utilization, as the chlorite, of all of the other metal whose chlorite is desired.

It' has been pointed out above that in practising the process exemplied'. by" Equation c, the anion of the salt' chosen to supply the one metal must be such that in combination with the metal of the base chosem a salt is formedwhose. solubility is diiferent from the metalr chlorate and the metal chlorite formed, tc- `facilitate their separation by commercially available facilities. Also, in practising the process exempliedby Equation d, these general considerationsreferred to in connection with Equation c apply with reference to the anions of the two salts and the. metal of the base.

It is of advantage that the third compound formed as described above in the reactions exempliiied by Equations c and d be appreciably less soluble than either the chlorate and/or the chlorite produced. In this case, it can be substantially completely removed from the system to leave remaining only amixtureof the chlorate and chlorite. of the alkaline earth metalsv is employed as the base, suitable metal salts, usedto. introducethe metal or metals of the chlorate and chlOrite, would include such saltsas the sulfate, fluoride, phosphate, silicate, fluorosilicate and arsenate. Further, if a magnesium alkali: isI employed as the source of the base, suitablemetal salts', used to introduce the metalormetals ofi the. chlorate and chlorite, would includesuch salts* asvthe iluoride, phosphate, silicate andar-senate,

The use of salts which ,decomposeA chlorites under the conditions. of; the processi is to be avoided. For example,. if potassium. dihydrogen phosphate were addedto a substantially neutral solution containing calcium. chlorite,. the resulting acidic solution wouldv decompose. the calcium chlorite. If, howeversuflicient alkaline material were present or added to neutralizeftheacid;salt, the acid salt could beused to. introducefthe phosphate ion.

Although it has been pointed out above that the third compound formedf'under the reactions exemplified Iby Equations cand d should. besuch that its solubility differs from. the solubility of the chlorate and chlorite to facilitateready separation of this third' compound.from.the other components of the system, it is recognized that a commercially valuable chlorate or chlorite. product would be produced, if the aforementioned third compound were left associated with either the chlorate or the chlorite. When. this is the case, the metal of the base andthe anion of the salt or salts selected` need' only be such that the third compound is selectivelyl soluble with reference to only one of the major products, namely, the chlorate or the'chlorite.

To exemplify the above noted. innovation to the processes represented. by 'Equations c.y and d, it is possible to use alkali metal bases. as well as. the alkali earth metal and magnesium.bases,A andv also to use such additionalV salts as the chlorides.

For example, if. an alkali of onev 6i andi nitrates: to introduce.Y the: metals! of; the` chloirateandi the chloritel.v An example .illustrating this'. mode of opera-tion is that of the. production oa' mixture of potassium chlorate, sodium chlo-` rite and sodium'. sulfate; mixturey can be. obtained: by thel reaction shown inthe following. equations:

In the procedurex shown by- Equation e, the potassium chlorate content of this mixture can besubstantially removedy byf evaporation andcrystallization to leave an essentially stoichiometrically equivalent mixture of sodium chlorite andi sodiumr sulfate. These latter two compoundsfcan bey recoveredtoge'ther te yield a sodium chlorite product containing sodium sulfate as a diluent.

It will be appreciated thata mixture of chio-` rites, for example, rather than a single chlorite,

could be produced by this invention simply bythe.

use of: twoA or more alkali compounds, o1' by the use of one alkali. .compoundl and the salts` .oftwo .or .more metals, Inthis way, the necessary metals for the formation of the mixture of chlorites are introduced.

It will 4be appreciated that the invention as fully exemplified above, canbe practiced so-that the various components required. need not. be introduced into the system in any particular sequence so. long as they all enter the system to. effect the reaction desired.

Although the oxides, hydroxides and carbonates. of the alkali metals, the alkaline. earth. metals andmagnesium have-been mentioned as .the alkali. compounds useful for the operation of thev invention,y the reaction rate is much. slower when carbonates are used than it is when oxides .orv hydroxides are employed. It is for this reason that the oxides and hydroxides are the preferred. alkalimaterials.

In carrying out the process of this inventionv in the preferred manner, chlorine dioxide, as. a dilute gas in the presence of such a diluent as. air or nitrogen, is reacted withan aqueous; slurry or. solution, as the case may be, of the desired alkali materials or the desired salt or salts and the alkali material. duced as a dilute gas to prevent the decomposition of the-chlorine dioxide. tration of chlorine. dioxide. in the gas phase is about 5% by volume. This concentration depends somewhat upon the temperature employed in the reaction, the lower thek temperature, the higher the safe concentration of chlorine dioxide which can be allowed. The temperature of the reaction can be varied5 from the freezing point to 100 C., a suitable temperature being ,50 C. The reaction rate increases with higher temperatures. However, thev preferred upper limit is about C.

The quantity of. water used for the reacting slurry or solution is not vital to the operation of the invention and may be varied over a. wide range. In general, sufficient water shouldl be. present at the end of the operation, and lbefore the products are separated, to keep the chlorate and chlorite in solution. and thereby prevent their precipitation along with the precipitation of the third compound, providing that it be desired toallow the third compound to be precipitated for removal from the` chlorate-chlorite. solution. If the invention is to be operated according, tol the This chlorine. dioxide is intro-.

A suitable concene process exemplied by Equation b, wherein only a chlorate and a chlorite are produced, it will be evident that it is only necessary to have sulcient water present to keep these two compounds in solution. However, if potassium chlorate be one of the compounds produced, for example, the amount of Water present may be reduced so as to cause the precipitation of some of the potassium chlorate. It further will be realized that should a compound, which it is desired to keep in solution, be inadvertently precipitated, additional water may be added to re-dissolve it.

In general, the amount of water in the reaction vessel wherein chlorine dioxide is being absorbed, should be enough to make the gas-liquid contact emcient. If too thick a slurry is used, diiiculty may be experienced in retaining a uniform suspension and in obtaining proper contact between the chlorine dioxide gas and the absorbing medium. Design of the apparatus for the adsorption of chlorine dioxide will dictate to a large degree the optimum thickness of slurry and, therefore, the quantity of water to be used. For most purposes, a suitable concentration of reactants is about 15% by Weight in the water slurry or solution. This quantity of water, for example, will keep all of the potassium chlorate of a solution containing equal moles of potassium chlorate and sodium chlorite in solution at 25 C.

After the reaction has been completed, the mixture of nal products is removed from the reactor for further treatment to separate the desired products. Inasmuch as the reactants and the products have been selected, as previously described, because of their mutually diilerent solubilities in any given system, the separation of the various products will entail the use of such common chemical engineering unit operations as evaporation, crystallization, washing and filtration.

Related subject matter is disclosed in applicants copending application, Serial No. 659,403, led April 2, 1946, which is directed to that specic embodiment in which chlorine dioxide and a single base are substantially completely reacted, and thereafter Without separation of the reaction products, a salt is introduced into the system.

Reference is here made also to applicants copending applications, Serial Nos. 736,113, led April 20, 1947, and 756,542, 756,543, 756,544, led June 23, 1947, which applications are directed to processes for the separation of various specific products which may be produced by the process of this application or the process of application 659,043.

This invention can be illustrated further and explained by the following examples:

Example I A slurry comprising 37 parts of calcium hydroxide, and 43.5 parts of potassium sulfate in 675 parts of water was reacted with 67.5 parts of chlorine dioxide While the slurry was kept at 50 C. Calcium sulfate in the amount of 34 parts precipitated and Was removed by filtration. The nal ltrate contained 61.2 parts of potassium chlorate and 43.7 parts of calcium chlorite and 684 parts of Water.

Example II A slurry comprising 37 parts of calcium hydroxide, 35.5 parts of sodium sulfate and 43.5 parts of potassium sulfate in 675 parts of water was reacted with 67.5 parts of chlorine dioxide while the slurry was kept at 50 C. Calcium sulfate in the amount of 68 parts precipitated and was removed by filtration. The iinal filtrate contained 61.2 parts of potassium chlorate and 45.2 parts of sodium chlorite and 684 parts of water.

Example III To a slurry of 20.16 parts of magnesium hydroxide, 43.6 parts of potassium sulfate and 27.5 parts of lithium sulfate in 675 parts of water were added 67.5 parts of chlorine dioxide. The resultant substantially neutralized solution then contained 60.2 parts of magnesium sulfate, 61.2 parts of potassium chlorate and 37.2 parts of lithium chlorite in 684 parts of water. These three components were separated from the system by appropriate physical separation methods. The potassium chlorate content was rst recovered, followed by a separation of the lithium chlorite and magnesium sulfate.

Example IV A solution of 56.1 parts of potassium hydroxide and 40 parts of sodium hydroxide in 640 parts of water was reacted with 135 parts of chlorine dioxide, the chlorine dioxide being introduced as a 5% by volume mixture with air. The 122.5 parts of potassium chlorate and the 90.5 parts of sodium chlorite were separated from the thus formed solution by evaporation of the solution to a point at which the solution was saturated with respect to sodium chlorite. About of the potassium chlorate content of the original solution was precipitated at 25 C., ltrated 01T and dried. The filtrate, containing all of the sodium chlorite and the residual potassium chlorate, was dried to give a solid sodium chlorite product.

Example V A solution saturated with respect to potassium sulfate and containing 80 parts of sodium hydroxide and 87 parts of potassium sulfate was reacted with parts of chlorine dioxide, the chlorine dioxide being in the form of a dilute gas in air, such that the chlorine dioxide concentration was approximately 30 mm. Hg. 'I'he 122.5 parts of potassium chlorate in the resultant solution were substantially separated by evaporation and filtration from the 90.5 parts of sodium chlorite and 7l parts of sodium sulfate. The remaining solution of sodium chlorite and sodium sulfate was reduced to a dry product by evaporation. The product thus formed contained about 55% sodium chlorite by weight.

Eample VI To a solution of 80 parts of sodium hydroxide and 77 parts of potassium silicate in 1500 parts of water were added 135 parts chlorine dioxide until the solution was substantially neutral. The 122.5 parts of potassium chlorate formed thereby were removed by evaporation and ltration from the sodium chlorite and sodium silicate also formed. The filtrate from this separation, containing 90.5 parts of sodium chlorite and 61 parts of sodium silicate, was evaporated to dryness to yield a product containing about 59% sodium chlorite by weight.

Ezcample VII This particular example is illustrated by the accompanying gure to indicate a useful iow sequence for the production of sodium chlorate and calcium chlorite from lime, sodium sulfate. and chlorine dioxide.

A slurry of 7.4pa'rts of calcium hydroxide and 71 parts of sodium sulfate irl-about 1500 fparts of ...Water was treated in absorber lwith .135parts of ;ihl'orinev dioxide,` the chlorine dioxide being in- Ltrodu'cedat about 5% concentration inI air -until 'lthe'"slurry 'was substantiallyneutralized. r The u"`slurry"of productsbparts'oi calcium sulfate, 106.5 partsl of-sodium chlorate and 87.5 parts oi ...calciumichlorite was filtered in iilter ii to remove #fthe-precipitatedcalcium sulfate. vFiltrate from 2,

containing the sodium chlorate and calcium chloriteplus a trace of vcalcium sulfate, :was evapof irated in evaporator to `aconcentration'suiiicient to keepall of the sodium chlorate in solution at 25 C. Considerable calcium chlorite precipitated during the evaporation and was removed in filter 4. The filtrate, now containing sodium chlorate in major quantity, was cooled in crystallizer to cause sodium chlorate to precipitate. Mother liquor from the crystallizeil 5, containing the unseparated sodium chlorate and calcium chlorite, was returned to the absorber I for recirculation.

What I claim is:

1. A process for producing a chlorate of a metal selected from the group consisting of lithium, sodium, potassium, calcium, barium, strontium and magnesium, and a chlorite of a diierent metal selected from said group which comprises reacting chlorine dioxide with a compound selected from the class of hydroxides and carbonates, and at least one soluble salt other than a carbonate as an additional reactant, the metals of said compound and said salt being different ones selected from the aforementioned group, said salt being present in approximately half the amount of said compound on a stoichiometrically equivalent basis, said compound and said salt being so selected that the metal oi the former reacts with the anion of the latter to form as a third product a salt of relatively different solubility than at least one of the desired products.

2. A process according to claim 1 in which the metal of the chlorate produced is furnished by said salt whereby substantially all of said metal present appears as the chlorate.

3. A process according to claim 1 in which the said third product formed is a relatively insoluble salt.

4. A process for producing a chlorate of a metal selected from the group consisting of lithium, sodium, potassium, calcium, barium, strontium and magnesium and a chlorite of a different metal which comprises reacting chlorine dioxide with a compound selected from the class consisting of hydroxides and carbonates, and as additional reactants two soluble salts other than carbonates, the metals of said compound and said two salts each being different ones selected from the aforementioned group, said two salts each being introduced in approximately half the amount of said compound on a stoichiometrically equivalent basis, said compound and said salts being so selected that the metal of the former reacts with the anions of the latter to form compounds of relatively different solubility than the desired chlorate and chlorite whereby the chlorate of the metal of one salt and the chlorite of the metal of the other salt is produced.

5. A process according to claim i in which the said salts have a common anion which combines with the metal of said compound to form a relatively insoluble salt.

6. A process according to claim 4 in which the said salts have a common anion.

7. A process for producing potassium chlorate and a chlorite of a metal selected'froni thegr'oup consisting of lithium, sodium; calciurri,"barium,

" strontium and magnesium, 'which' comprises referentones selected from' the group consisting of lithium, sodium, potassium, calcium, barium,

i vstrontium and magnesium and one of the metals being potassium, saidsalt being present inap proximately half the"amount of said compound on a stoichiometrically.equivalent basis, and said compound and said salt being so selected that the metal ofthe'iormer reactswith thefanion of the latter to form as a third product a-saltfoifrelatively different solubility than at least one of the desired products.

8. A process according to claim 7 in which the potassium is introduced in the form of said soluble salt whereby substantially all of the potassium appears as the chlorate.

9. A process according to claim 7 in which the soluble salt is a potassium salt having an anion which combines with the selected metal of said compound to form a relatively insoluble salt as the third product.

10. A process for producing potassium chlorate and a chlorite of a metal selected from the group consisting of lithium, sodium, calcium, barium, strontium and magnesium, comprising reacting chlorine dioxide, a compound selected from the class consisting of hydroxides and carbonates, and as additional reactants two soluble salts other than carbonates, the metals of said compound and said salts each being different ones selected from the group consisting of lithium, sodium, potassium, calcium, barium, strontium and magnesium, the metal of one of said salts being potassium and the metal of the other salt being that of the desired chlorite, each of said salts being introduced in approximately half the amount of said compound on a stoichiometrically equivalent basis, said compound and said salts being so selected that the metal of the former reacts with the anions of the latter to form additional salt products of relatively different solubility than potassium chlorate and the desired chlorite.

11. A process according to claim 10 in which the said two salts have a common anion which combines with the metal of said compound to form a relatively insoluble salt.

l2. A process according to claim 10 in which the said two salts have a common anion.

13. A process for producing a chlorate of a metal selected from the group consisting of lithiurn, sodium, potassium, calcium, barium, strontium and magnesium, and a chlorite of a different metal selected from said group which comprises reacting chlorine dioxide with a compound selected from the class consisting of hydroxides and carbonates, and as a third reactant a soluble salt other than a carbonate, the metals of said compound and said salt being diierent ones selected from the aforementioned group, said salt being present in approximately half the amount of said compound on a stoichiometrically equivalent basis, said compound and said salt being so selected that the metal of the former reacts with the anion of the latter to form as a third product a salt of relatively different solubility than at least one of the desired products.

14. A process according to claim 13 in which potassium chlorate is produced and in which po- 1l tassium is the metal of the salt present as the third reactant.

15. A process for the production of potassium chlorate and calcium chlorite which comprises reacting chlorine dioxide in aqueous medium with calcium hydroxide in the presence of potassium sulfate, said sulfate being present in about half the amount of the hydroxide on a stochiometrically equivalent basis whereby is formed potassium chlorate, calcium chlorite and calcium sulfate, and separating the chlorate and chlorite from the precipitated calcium sulfate.

CLIFFORD A. HAMPEL.

REFERENCES CITED The following references are of record in the me of this patent:

OTHER REFERENCES Mellor, Comprehensive Treatise on Inorganic and Theoretical Chemistry, 1922, vol. 2, pp. 282, 283 and 284.

Seidell, Solubilities of Inorg. and Org. Compounds, vol. I, D. Van Nostrand & Co., New York,

1919, pp. 513 and 639.