T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
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Vol. 6, No. 3
LDITORIALS
FACTORS INVOLVED IN OPENING UP THE FIELD OF UNUSED ELEMENTS1 I n attempting t o classify t h e accepted elements so t h a t one group, or pseudo-group,contains those elements designated “unused,” or “little used,” one is confronted with many difficulties. T h e prime difficulties involve t h e purpose of t h e classification a n d t h e ext e n t of t h e use. Over one-third of t h e accepted chemical elements have no serious commercial uses a t present as elements or compounds. These are given below, classified according t o t h e periodic system for convenience: 0 He Ne A Kr Xe Nt
ELEMENTSOR COMPOUNDS UNUSEDOR LITTLEUSED 1 2 3 4 5 6 7 8 Unclas Pr Rb Be Sc Ge Cb Se Ru Cs Sr Y Yb Te Rh Nd La Os Sm Ga Eu In Gd Er DY T1 Tm LU
Tb
About one-half of these have been discovered within t h e last t h i r t y years. Those so recently made known are usually classified under t h e two groups of “rare gases” a n d “ r a r e earths.” Attention is directed t o t h e melting points and specific gravities of four of t h e rare-earths. MELTINGPOINTS Ce = 623O C. La = 810’ C. N d = 840’ C. Pr = 940° C. A1 = 660’C.
SPECIFIC GRAVITIES La = 6.15 Pr = 6.48 hTd = 6.96 Ce = 7.01
Cerium has about t h e same density as t i n ( 7 . 3 1 , b u t all four readily oxidize on exposure t o air. Cerium is between lead a n d tin in its physical appearance, b u t harder t h a n t i n ; l a n t h a n u m acts much like metallic calcium, its oxide combining readily with water t o form t h e hydroxide, being air slaked, as is lime. T h e word “ r a r e ” so applied above-as is t h e case with many words of qualification-has changed its meaning in t h e light of very recent investigations, although t h e “ r a r e gases” are found in t h e atmosphere in t h e following proportions: NAME ATOMIC WT. 4.0 Helium. . . . . . . . . . . . . . . . . . . . . h-eon.. . . . . . . . . . . . . . . . . . . . . . 20,O Argon . . . . . . . . . . . . . . . . . . . . . . 39.9 Krypton.. . . . . . . . . . . . . . . . . . . 81.8 X e n o n . . .................... 128,O
1 V O L . IN 2 , 4 5 0 vols. air 808 vols. air
105 vols. air 746,000 vols. air
3,846,000 vols. air
Some of t h e elements mentioned above are b y no means so uncommon now a n d may be h a d in commercial quantities. Below is a table containing these a n d some other elements. Many of these have been known for a long time; they are not now used extensively, b u t invite application. 1 Author’s abstract of an address before the Joint Meeting of the New Yark Sections of the American Electrochemical Society, the American Chemical Society and the Society of Chemical Industry, at The Chemists’ Club, New York. February 6 , 1914.
ELEMENTS h-ow AVAILABLE COMMERCIALLY BUT LITTLEUSED 0
A
1 K
2 Ca Sr Ba Cd
3 B
Y La
4 Si Zr Ce
5 As Cb Ta
6 Se Te
7
8
Br I
Co
Unclas.
Pd
Th
Now t h a t we have seen t h e field, let us see what are some of t h e factors involved in cultivating it. I n some cases we lay t h e lack of use of t h e elements a t once t o t h e scarcity of known occurrences. Haber has shown t h a t osmium is t h e best catalyzer for making ammonia from its elements, b u t von Welsbach, who devised t h e osmium-filament lamp, has calculated t h a t there are only a few hundred pounds of osmium available in t h e periphery of our globe. When, however, we remember t h a t carbon is b u t 0 . 2 1 per cent while silicon is 2 5 . 3 per cent of t h e crust of our earth for a depth of ten miles, including t h e waters on t h e earth a n d its surrounding atmosphere, according t o Clarke’s calculations, we know t h a t our present utilization of the elements commercially bears b u t little relation t o their total quantity. With some striking exceptions, man has-found more or less ample sources of t h e elements or their compounds when it has been shown t h a t our civilization required them. Tungsten, thorium. vanadium, a n d radium only need be mentioned in illustration. It is not t h e small percentage in which these elements occur, for palladium exists in nickeliferous pyrrhotites in quantities too small t o be detected b y even refined chemical analysis, b u t i t accumulates in t h e slimes of nickel refineries and is thus obtained in some quantity. T h e price fixed by possession is t h e deterrent in t h e development of t h e use of palladium. a fact of no individual immorality-quite human perhaps-but contrary t o t h e laws of economics. Some ten years ago one large corporation possessing a store of palladium was approached b y some technologists, supported b y good repute, with t h e idea of working out uses for t h a t by-product. The owners said they were not interested in spending a thousand dollars on t h e investigation-they did not mind spending t h e money, b u t t h e y would not be a p a r t y t o lowering t h e price of t h e material in their possession, t h e inevitable result of extending its use. This principle is well illustrated in t h e history of metallic aluminum a n d thorium oxide whose market quotations have fallen t o one one-hundredth a n d two one-hundredths, respectively, what t h e y were one generation ago. On account of its great resistance t o atmospheric oxidatio‘n a n d moisture a n d t o t h e effect of sulfuretted gases, palladium has been employed for t h e inner mechanisn of chronometers a n d watches, for t h e construction of fine balance-beams, for t h e division scales of delicate apparatus, a n d for surgical instruments. I t has been used for coating silver goods, and for electroplating searchlight mirrors, for soldering platinum, a n d in dental preparations. Palladinized asbestos, palladium sponge a n d palladium black are most efficient catalytic substances for reducing purposes.
Mar., 1914
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
This well known fact m a y be flashed from t h e housetops without a n y fear of coagulating t h e clouds of litigation hovering over t h e oil-hardening situation in this country, as t h e parties referred t o still own t h e palladium. Some of these “ u n u s e d ” elements will be used, if t h e prices are made more reasonable. A very important factor in reducing t h e market prices of these substances is a n improvement in methods of extraction. This m a y be illustrated in t h e case of t h e rare-earths, not with t h e intention of leading t h e reader into t h a t maze, b u t because i t shows how modern tools have served t h e purpose a n d gives suggestions for needed extension with other elements i n t h a t class of “meta-elements,” as Crookes termed them. Monazite sand is essentially a phosphate of t b e rare earths containing variable amounts of thorium, usually 4-6 per cent. T h e problem of obtaining thorium compounds from t h a t source--g I j,OOo,OoO Welsbach mantles was t h e world’s o u t p u t in 1913-depends upon: ( I ) Solution, usually b y baking, with concentrated sulfuric acid a n d leaching (very fine grinding of t h e sand was a n essential preliminary) ; ( 2 ) T h e rare earths a n d thorium were t h e n thrown o u t as oxalates t o remove t h e last trace of phosphoric acid; (3) T h e mixed oxalates were brought into solution with t h e destruction of t h e oxalic acid a n d t h e thorium precipitated; or, t h e oxalates were treated with ammonium oxalate, whereby t h e nonahydrated-thorium-tetra-ammonium oxalate went into solution. This thorium salt was subsequently converted into nitrate. With all this procedure, t h e price of thorium salts steadily declined until it seemed t o reach a limit. M u t h m a n n a n d Weiss conceived t h e plan of distilling off t h e phosphorus a n d converting t h e metallic elements present into carbides. T h e resultant mass is hard a n d is very expensive t o grind in order subsequently t o dissolve it. T h e writer later produced calcium carbide within t h e mixture of other carbides, using t h e unground monazite sand. This mass when thrown into water crumbled a t once t o a powder from which t h e suspended milk of lime is readily washed. T h e residual mass goes into solution in commercial hydrochloric acid from which t h e thorium m a y be precipitated a t once in a form readily soluble in nitric acid. T h e cerium m a y be thrown out of t h e solution from t h e thorium precipitate a n d tons of oxalic acid are not destroyed or locked u p in t h e large quantities of rare-earths accumulated awaiting t h e development of uses. M u t h m a n n a n d Weiss a n d Hirsch in this country have applied t h e Hall process for t h e isolation of metallic cerium, whose use is now practically limited t o pyrophoric alloys. T h e price of metallic cerium in Germany has recently fallen from $60 t o $ 5 per kilogram. Very recently i t has been proven t o be distinctly profitable, according t o separate patents of Soddy a n d H a h n , t o separate meso-thorium compounds in t h e process of extracting a n d purifying t h e thoria. Mesothorium rivals -radium in some of its applicatidns i n radio-surgery. T h e three instances cited above are given for another
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reason. T h e ideas were worked out b y three college professors. Laborers must be provided for clearing t h e field, whether t h e toil be t h a t of working out new processes t o so reduce t h e cost of a material as t o a d m i t of its application t o uses already known t o exist, or devise uses not now known for by-products quoted a t fictitious prices, b u t which d o not appear at such supposititious values in t h e annual financial statement. Cndoubtedly t h e best way t o work o u t problems of t h e utilization of “undeveloped elements ” is t o a t t a c k t h e m in such well-equipped a n d splendidly manned research laboratories as are maintained by t h e General Electric Co., t h e General Chemical Co., t h e E a s t m a n Kodak Co., a n d others, b u t their upkeep involves large expenditures. M a n y college a n d university professors would welcome a subsidy f o r work of this character, which should be scientific, dignified, a n d help keep t h e wolf from t h e door. We commend for your perusal t h e amusing “Confessions of a College Professor’s Wife,” in a recent number of The Saturday Eveiting Post. We do not mean t h a t t h e college professor is prepared t o or should go into t h e factory, b u t he can work a t a n idea, which should later be developed, if i t has merit, on a commercial scale b y t h e technical chemist or chemical engineer of t h e works. Elaboration of this proposition, which is not novel with t h e speaker, is not necessary here. Suffice i t to say t h a t one so selected would bring t o t h e problem a degree of ignorance t h a t might be stimulating a n d a freedom f r o m tradition which would admit of a display of imagination necessary t o utilize material which is commercially a b u n d a n t . H. B. Baker has said somewhere, “ S o t h i n g can be of more value t o science t h a n t h e exhaustive s t u d y of one particular action.” Weiss a n d S e u m a n n have f o u n d t h a t compressed zirconium is a conductor, whereas previous statements have been t h a t it was non-conducting. There is need for reviewing many such statements t h a t are handed down in t h e literature. Aluminum is sonorous, according t o so m a n y text books. Yery pure aluminum, such as t h a t used b y t h e late Professor Mallet in t h e determination of its atomic weight, is not sonorous. If aluminum is sonorous, i t is not pure. Stewart in his charming book on “Recent Advances in Physical a n d Inorganic Chemistry,” in referring t o 1887 a n d t h e following years of feverish activity in physico-chemical r e d a r c h , led by Arrhenius, van’t Hoff a n d t h e elder Ostwald, says: “ T o some extent this wave appears t o have spent its force. At t h e present d a y physical chemistry, except in t h e hands of a few exceptional researchers, has degenerated into a means of attacking t h e problems of pure chemistry instead of opening up new fields; a n d consequently there is a certain tendency t o decry t h e subject as a mere means t o a n end, a n d not a living branch of science. This is, perhaps, a n exaggerated view; b u t it cannot be denied t h a t physical chemists of t h e present d a y are not animated b y t h e high hopes which seem t o have inspired Ostwald a n d others in t h e earlier days of t h e subject.” Bancroft acknowledges t h a t there is some t r u t h in this criticism, b u t asserts, “ T h e difficulty is t h a t most people are still struggling under t h e
T H E J O U R N A L O F I N D G S T R I A L A S D ENGIL\TEERI_VG C H E M I S T R Y limitations imposed deliberately a n d consciously b y Ostwald. Once these are broken through, nobody will have a n y cause t o complain of t h e wave having spent its force.” Stewart further says: “ I t is a n extremely f o r t u n a t e coincidence t h a t as t h e first movement declined, a second a n d perhaps more powerful one h a d succeeded it. This second movement rose with even greater rapidity t h a n pure physical chemistry, a n d yet a t t h e present d a y we appear t o have touched only t h e fringe of t h e subject of radioactivity; so t h a t we m a y look forward t o a long career of fruitful investigation still before us in this department of chemistry.” T h e problems of sub-atomic or electronic universe have presented themselves a n d a t once we begin applying these new ideas t o utilitarian purposes. T h e cryogenic laboratories have accumulated fractions from tons of liquefied air. Collie found t h a t t h e neon. obtained t h u s incidentally, luminesces under t h e influence of t h e Hertzian waves. A t u b e of neon serves as a detector of t h e nodes a n d loops, glowing brilliantly under t h e influence of t h e latter, as if it were excited b y a n induction coil. Claude’s tubes of neon t h u s excited, offer a most pleasing light a n d perhaps later on will prove t o be a n economical source of artificial illumination. Quantities of argon are now available from liquefied air. There are indications t h a t , on account of i t s inertness, we m a y shortly see tungsten incandescent lamps, as Whitney p u t s it, with “ t h e vacuum jam-full of argon” instead of nitrogen. Troost a n d Onvrard have stated t h a t t h e y h a d succeeded in causing argon t o combine with magnesium vapor. Neither Rayleigh, Ramsay, nor Moissan were able t o secure a n y evidence of t h e formation of compounds of argon, however. M a n y reactions unobserved on t h e laboratory scale are found t o occur when dealing with large quantities of substances, through long periods of time. If this were n o t t r u e we should h a v e even greater difficulty in accounting for t h e occurrence of such inert gases as helium in malacome, clevkite a n d thorianite. It is t h u s barely possible t h a t in time we shall find compounds of argon produced in t h e large scale operations of burning t h e nitrogen of t h e air, as carried on so successfully in Korway
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a t present. h use of compounds of argon m a y t h e n be found. T h e development of radioactivity has projected us into a n undreamed of realm of thought a n d new interests. T h e phenomena of radiology are closely allied t o those of radioactivity. T h e use of Rontgen rays in medicine has been attended b y not a few difficulties. Among t h e m t h e so-called “hardness” a n d “softness” of t h e rays. T h e former are penetrating a n d affect tissues far below t h e surface, sometimes favorably a n d sometimes unfavorably. The “ s o f t ” rays affect t h e epidermis. I n t h e use of “ h a r d ” Xrays tubes for deep t r e a t m e n t , i t is necessary t o screen t h e skin with various thicknesses of aluminum, or lead, etc. For treatment of skin affections only, there have been no satisfactory means for screening out t h e penetrating rays, consequently a problem has been t h e production of “ s o f t ” rays with a minimum of “ h a r d ” rays. X-ray t u b e glass is usually a potash or sodalime silicate. Lindemann found t h a t b y substituting lithium for potassium t h e rays were “softer.” H e then substituted beryllium for calcium, a n d finally boron for silicon. Lithium-beryllium-boron-glass shows over t h i r t y per cent reduction in t h e empirical molecular ireight. Windows of this glass let into X-ray tubes give t h e “ s o f t ” rays desired. It would be interesting t o see t h e effect with a potassium-barium-zirconium-glass. Application of t h e newer electronic conceptions of valence, especially when associated with residual affinity with t h e development of methods for changing valence according t o our wishes, will unquestionably cause m a n y of these unused elements a n d m a n y of those now most used t o assume new properties. A t tention m a y be directed t o one qualitative illustration. Pure lead does not plate on iron. When molten lead is caused t o flow t o a n d fro as a conductor of a lowvoltage high-amperage alternating current for variable periods of time, usually several hours, i t t h e n plates iron, as m a y be seen from samples very recently so plated under t h e supervision of t h e writer. While t h e process is not perfected, it points a way which m a y serve as a hint in seeking uses for such elements as cadmium, selenium, a n d tellurium. C H A R L E SBASKERVILLE
ORIGINAL PAPERS PAINT FILMS A S PROTECTIVE COATINGS FOR CONCRETE. By E. E. WARE A K D S. M. S C H O T T ~ Received December 9, 1913
T h e extensive use of concrete as a building material for all types of construction has naturally been accompanied b y numerous failures of greater or less importance. These examples have been seized upon b y manufacturers of competitive material a n d have been brought t o t h e attention of t h e public through wide publicity, causing a d o u b t t o arise in t h e minds of some as t o t h e permanence of concrete construction. 1 Holder of Paint Fellowship, Acme White Lead and Color Works, 1911-1912.
However, with t h e better understanding of t h e possibilities a n d t h e limitations of this material, it has been possible t o very nearly eliminate t h e causes of failure t h a t were mainly responsible for t h e difficulties experienced b y t h e pioneers in t h e use of concrete construction. B u t we are confronted b y a cause of disintegration still little appreciated b y t h e concrete engineer-lack of constancy of volume in concrete after setting. Although t h e tendency t o failure from this cause is more, apparent in stucco a n d other light construction, where mixtures rich i n cement are used, monolithic work is b y n o means free from t h e effects of this lack
