Patented May 1, 1923. 1,45%,562 UNITED SATES P All.‘ bl if" til? . ROBERT E. WILSON, LEON ‘JV. PARSONS, AND STANLEY 1E. OHXSHOLIYI, OF WASHINGTON, DISTRICT OF COLUMBIA. PROCESS THE PRODUCTION OE‘ All‘HALLEAETELMLETAL PERTJIANGANATES. N0 Drawing". Application ?led September 27, 1918. Serial No. 255,975. To (all to]: am it may concern. .' manganate by oxidation or acidification, Be it known that we, Romain‘ E. lllinsou, metatheses into calcium pern'iangamite by LEON “7. Parsons, and STANLEY L. Unis treatment With calcium sulphate or milk at HoLM, citizens of the United States. and sta lime. tioned at ViTashington, District of Columbia, O'li' these four possible methods, (1.) is not 60 in the o?icc of the Director the Chemical a possible large scale method. on account l/Varfare Service, Research Division, have in of its use ot silver; (2) and are elec vented a Process for the ll’roduction oif Al trolytic methods Without a. great deal out kali-Earth-l\letal Permanpjanates, of which promise, and are to be considered elsewhere; ll) the ‘following is a speci?cation. (ll) the principal subject of this applica G3 in The present invention relates to the pro tion. duction oi? alkah» earth metal permangam Three distinct methods for preparing: ba~ nates and especially the permanganates of rium (or strontium) manganate have been calcium and magnesium as these have beenv here investigated. The ?rst of? these meth found to be very ellicient oxidizing agents ods involves heating together barium perox 70 for certain purposes, more e?icient even. than ide, hydroxide, or a salt, such as the nitrate the permanganates of the allmliearth metals. or chlorate,‘ witl an oxide of manganese, as This superiority is shown in the so-called manganese dioxide. Considerable iWOl'l’I has “British soda lime granules.” been done upon fusions ot this type, and More specifically, the object of‘ the inven beautiful green products were obtained, but tion. is the development of a commercial the most tavorable results obtained gave process oiliproducing the alkali-earth metal products containing only FS—lO“-"o milling,“ permanganates, since so tar as We are aware. the rest oi’ the product consistinc,r of residual their manufacture in quantity has never M1102, Ball and the Ball/int), from the been attempted on a large scale or even on thermal decomposition of the mangranate. a small. scale, except in Germany, Where The thorough n'iiningr of such dry sinteringi's they have been produced by a. rather expen is retl'icr :litlicult, but quite necessary; indeed sive electrolytic process starting with potas even the ‘fusions should be stirred to give the sium permanganate (Kb/[1104), best results. 30 lWe have discovered that calcium or map; The second and more preferable of these 00 L1 nesium pern'ianganate cannot be prepared methods involves the reaction of‘ similar mimw directly by ordinary, methods but that indi tures in a- low melt-ins; fused medium. such as rect methods must be used. e. g... by ?rst ‘fused sodium hydroxide, or sodium nitrate forming a. manganate, oxidizing; this, and at temperatures Well below a red heat. The neutralizing the perinauganic acid so termed cooled fused mass is extracted with Water. With barium, calcium or magnesium hydrox the ?ltrate containing chiefly NaOll or ide. _ - NaNUS being; evaporated to dryness, and the Vile have investigated very thoroughly the fusion medium being; returned to the proc possible methods of makingv calcium per ess. The insoluble residue cou'.. s ot a 40 mangana-te and believe that only tour of basic barium manganiunanganate contaiuiiuy 9 5 them are at all workable. These are: 20-32% Bail’lnfh, together with excess i (1) Preparation of silver permansenate MnO.,. etc.‘ This represents a decided grain by crystallization from slowly cooled solu over the first, or dry ‘Fusions. tions of silver nitrate and potassium or so llloth o‘l? these methods7 however, in many dium permanganate. Calcium permanga ways appear less attractive than a. third nate is then forn'ied metatheticallyI by treat method, which consists in boiling _“green ment with calcium chloride. leachings” containing about 8% (2) Selective transference and oxidation 4 tint)‘ and ‘lb-420% NaO'H, With a sol electrolysis of sodium or potassium manga uble barium compound, such as the hydrox note or permanganate and milk of lime or a ide or chloride,?ltering oil and washing the Illij calcium. salt. I insoluble barium manganate precipitate and (3) Electrolysis of term manganese anode evaporating down the ?ltrate to return‘the into solution of a calcium salt. caustic to the process in the “green ash” ‘(4) Preparation of barium manganate by (manganate) fusion. Barium manganate fusion or wet‘methods, conversion to per— precipitates obtained on a small scale in In; 1,453,562 this wet way contained 70—75% Ba-MnO“ most practicable for technical use. Bro the remainder appearing to consist of ab mine is barred. because of its scarcity and sorbed alkali and alkaline salts and barium cost. The use of ozone is entirely too ex carbonate, unless the green liquor has been pensive. ,l?ven electrolytic oxidation meth previously boiled with milk of lime to re ods, relatively much more e?icient than the move the carbonate almost invariably pres ozonizing methods, involve much expensive ent. Even in this case the precipitate gen apparatus. erally contains some carbonate due to ab Chlorination is undoubtedly the best and sorption of atmospheric carbon dioxide dur most economical )rocess of converting ing manipulation of the alkaline barium BaMnO, into Ba(l\ln()4)2 for any purpose 75 mixtures. The use of the barium hydroxide where the large amount of chloride im would probably be preferable to that of a purities could be tolerated. The nitric acid salt such as the chloride as no impurities are process is undoubtedly the next best, and thus introduced into the caustic ?ltrate, to it appears from the data now available that 15 prevent its reuse in the‘ green' ash fusion. by careful removal of the nitrate formed The preliminary removal of carbonate with by crystallization, a product pure enough Ca(OH)2 is preferable to using Ba(OH)2 for certain more special uses may be made. for this purpose. , If still greater purity is required recourse Such mixtures during treatment, should must be had to the carbonation or sulpha not be allowed to evaporate‘ too far, as’ tion methods. Each has some advantages. oxygen is then evolved, with the formation but both have serious disadvantages for of a basic manganrm’anganate similar to practical commercial operation. ‘The ?nal the product mentioned above in connection choice between the two would probably de with the caustic fusions. Thus by evaporat pend on local plant conditions. The 25 ing to pasty-dryness, and thoroughly ex Ca(i\’lnO,,)2 is'made by either of two ways, 90 tracting with water, a dark blue green depending on the process used in oxidizing residue is obtained, in place of ‘the “smalt the BaMnOr If Ba (MnO,)2 is made, the blau’7 manganate, which contains only about calcium salt is made by metathesis with 40% Ba'MnO4. CaS(),, ?ltering off the B2180‘. Owing to To summarize, probably the best method the much greater stability of Ba(MnO,)., as of making BaMnO, is by a preliminary compared with Ca(l\ln(),,)2 all possible puri fusion of NaOH and MnOg, which is ?cation. ?ltration and concentration should bleached, filtered and treated first with be done before the ?nal conversion to Ca(OH)2 to precipitate CaCOm and then Ca(.\1tn(),)2 is made. with. Ba(OH)2 to precipitate BaMnOp \Vhen a solutionv or a suspension of a Ion This gives a. very high purity B'aMnO4 with manganate is acidi?ed, manganic acid. be a minimum amount of BaO used. Consid ing very unstable, breaks down into the rela ering the great saving‘ in the later conver tively much more stable permanganic acid sion of this material to permanganate this and manganese dioxide. Pcrmanganic acid. 40 method is undoubtedly the cheapest. while relatively much more stable than lllii Barium manganate is an intermediate mauganic acid, is, however. quite unstable product in the manufacture of barium, cal‘— except at low concentrations and low tem ciun'i and magnesium permanganates. Ba peratures. Any plan of acid treatment in rium manganate, as prepared by either fu volved in permanganate manufacture must sion or precipitation methods may be con take into account this instability. The ac~ llo verted into barium permanganate either by tion of light is similar but much less ap direct oxidation, as by the use of chlorine preciable than that of heat. or ozone, or by the action of acids, the lib— The action of carbon dioxide, or of nitric erated manganic acid acting‘ as its own ox and sulphuric acid respectively, may be re 50 idizing agent, being itself partially reduced garded as that of typical acids as regards the to manganese dioxide in consequence. The reaction and the products obtained. (‘arbon calcium permanganate may be obtained by dioxide is of course a gas with very slight metathesis with the somewhat soluble cal solubility in water, giving an acid solution cium sulphate, or’ by'n‘eutralizing the acid of exceedingly low hydrogen ion concentra solution‘ of permanganate with milk of tion. and in consequencedrives the reaction lime; . ., to completion, mainly by removing’ insolu Of these" two, methods, direct oxidation, ble equilibrium products. on the one hand, and ‘indirect oxidation, by acids on“ the other harid,_the former appears 60 tov be at. first sightrpreferable, because of its directness and because none of the product This reaction is complete and irreversible isjused up in the process.