June, 1917
T H E J O C R N A L O F I S D C S T R I d L A N D ENGILVEERI.VG C H E M I S T R Y
(2) combustion with concentrated sulfuric acid , t o which potassium dichromate had been a d d e d ; a n d (3) combustion of t h e residue after moist combustion with cupric oxide in a current of oxygen. Determination of t h e carbonate in t h e soil gave results less t h a n 0.01per cent carbon and this has been ignored as a negligible quantity. I t was originally proposed t o subject t h e residue from t h e treatment with sulfuric acid a n d dichromate after washing and drying t o combustion with cupric oxide, b u t i t was found ‘that this material h a d absorbed a considerable quantity of chromium compounds and gave so much sulfur trioxide on heating t h a t it was not possible t o obtain concordant results for carbon when treated. in this way, and in place another portion of soil was treated with sulfuric acid and potassium sulfate as in a Kjeldahl digestion, heated until all organic matter was destroyed and t h e residue perfectly white, washed, dried and n-eighed. The following results were obtained, all figures being t h e mean of three closely agreeing results. T h e figures obtained on combustion of t h e residue after treatment with sulfuric acid and potassium sulfate m-ere calculated t o original soil.
TOTAL CARBOF Per cent l I o i s t combustion., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.71 Cupric oxide combustion of residue from moist w m bustion, . . . . . . . . . . . . . . . 0.12 I n soil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cupric oxide combustion.. .........................
589
quartz grains proceeds slom4y, and if t h e combustion is stopped a t t h e end of t h e period usually adopted, calcite inclusions can still be found under t h e microscope a n d t h e material will give more carbon dioxide on further heating. Theoretically if the soil n-ere ground so fine t h a t all calcite inclusions were exposed t h e carbon dioxide of such calcite would appear in t h e preliminary carbon dioxide determination and no error would be introduced in t h e subsequent combustion b y t h e cupric oxide method, b u t it does seem possible t o accomplish this in practice. I t is evident t h a t t h e inclusions are exceedingly minute, for the carbon dioxide calculated t o carbon in t h e preliminary carbon dioxide deterniination was less t h a n 0.01per cent, while t h a t obtained from t h e calcite inclusions by cupric oxide combustion n-as 0 . 1 2 per cent, working with a soil ground t o pass a sieve of 80 meshes t o the inch. T h e residue from a moist combustion after washing and drying was ground t o pass a sieve 130 meshes t o t h e inch and then leached with hydrochloric acid, and after this treatment calcite inclusions were still abundant when examined under t h e microscope. I t is, of course, apparent t h a t in a n y coniparison of methods all determinations should be made on samples ground t o t h e same degree of fineness.
s.
L-. DEPARTMENT O F -kGRlCLXTcRE BVREACOF SOILS, ~V-ISHINGTOS
0.83 0.80
-~
.~
SULFATE It is seen from these figures t h a t there is a reasonably close agreement between t h e total carbon obtained b y By R . F. GARDIXERA X D EDMUND C. SHOREP direct cupric oxide combustion of t h e soil, and t h a t Received February 16, 1917 obtained b y adding together t h a t obtained on moist Muscovite, one of t h e micas, is a mineral frequently combustion a n d cupric oxide combustion of t h e resifound in t h e rocks from which soils are formed and is a due. commonly occurring mineral in soils. I n some soil It has been frequently noted that moist combustion series i t is one of the characteristic or predominating methods have given figures for total carbon i n minerals, for instance in a sample of Gloucester stony soils than those obtained with cupric oxicle, and with loam after mechanical separation t h e sands were found the idea that the latter was an absolute method, it has been held that the moist combustion method fie- t o contain j per cent of muscovite and t h e silt 30 per quently gives figures lower t h a n t h e actual amount. cent. I n the same way a Of Perm loam The results obtained indicate that if this discrepancy was found t o contain 6 per cent of muscovite in the sand is found in t h e case of soils containing calcite included and per cent in the ‘Onsidered One Of the most Muscovite is in quartz. t h e facts are quite t h e contrary so far as total stable of soil minerals. Clark says,* “Muscovite, organic carbon is concerned. under ordinary circumstances, is one of t h e least alterof soils containing calcite I n other lvords, i n the able of minerals. T h e feldspar of a granite may be inclusions, t h e carbon dioxide of such calcite will not appear in t h e ordinary carbon dioxide determination completely kaolinized while the embedded plates Of b u t will appear i n t h e cupric oxide combustion and mica retain their brilliancy unchanged*” AfcCaughey a n d F r y say,3 “The micas are persistent b e calculated t o organic carbon. This is not t h e case with the moist combustion method and it m,ould Seem minerals in soils and show b u t little evidence of alterafair t o assume t h a t in case of soils containing calcite tion, a fraying of t h e edges a t times being quite charinclusions the figures obtained for organic: carbdn by acteristic, If alteration of t h e micas has t a k e n place this method are nlore nearly t h e t r u e value t h a n those i t has not influenced their Optical properties* It mould appear t h a t micas are t h e most stable of t h e b y t h e cupric oxide method. potash minerals found in soils except microline.” It should be stated in this connection that in order Johnstone reports t h a t after suspension of mica for a to obtain all the carbon dioxide in combustion of such soils b y the cupric oxide method the heating must be year in water charged with carbon dioxide very little be discerned.’ prolonged much beyond t h e t i m e ordinarily t a k e n for 1 U. S. Dept. Agriculture, Bull. 122 (1914). t h e oxidation of t h e organic matter. It would seem 2 “The D a t a of Geochemistry,” U. S. Geol. Surz’ny, 616, 1916. t h a t t h e decomposition of t h e included calcite a n d t h e Bureau of soils, u, s, Dept, Agr,, Bull. Bi (1913!. escape of t h e carbon dioxide b y t h e rupture of t h e 4 Qiiarterl)’ J . Geol. Soc. London. 45 (1889).
THE
OF SoLUT1oNS OF ON MUSCOVITE
5 90
T H E J O l - R X A L O F I * V D U S T R I r l L AiVD E N G I N E E R I N G C H E M I S T R Y
On t h e other h a n d , Steiger found " t h a t by a very superficial t r e a t m e n t with hydrochloric acid approximately one-third of t h e potassium may be extracted."' I n t h e s t u d y of t h e alteration of soil minerals in this Bureau one of t h e procedures adopted has been t h e subjection of t h e finely ground mineral t o t h e action of solutions of salts, either those known to be present in soils or commonly added t o soils in fertilizers. I n t h e course of this work t h e behavior of finely ground muscovite when treated with a solution of ammonium sulfate was such t h a t while preliminary work only has as yet been done t h e results seem worthy of record. Selected laminae of muscovite f r o m a large sample of this mineral were ground in a n agate mortar t o pass a sieve 1 3 0 meshes t o t h e inch. This material in varying quantities was subjected t o t h e action of I O cc. of a solution of ammonium sulfate varying in concentration from 0 . j t o 1.5 per cent. T h e insoluble material was removed b y filtration a n d t h e total potassium i n t h e solution was determined b y t h e official method for potash i n mixed fertilizers. T h e t o t a l potassium i n t h e original muscovite was determined b y t h e J. Lawrence Smith method. T h e results are shown i n t h e accompanying table. T h e length of t i m e of contact of t h e solution with t h e muscovite was i n all cases 24 hours; I O cc. of t h e a m monium sulfate solution were used i n each experiment. T h e results obtained with orthoclase b y t h e same t r e a t m e n t are also shown. I n additions t o these tests, t w o portions of 0.5 g. of muscovite were heated i n a n autoclave for I hr. a t 160' C., i n one case with water only, a n d i n t h e other with 2 5 cc. of a 4 per cent solution of ammonium sulfate. I n t h e case of water 4.32 per cent of t h e t o t a l potassium as KtO was rendered soluble, a n d i n t h e case of t h e ammonium sulfate t r e a t m e n t 47.3 per cent. I n t h e first three tests, where t h e concentration of t h e 1
I
U. S. Geol. Survey, Part I, Bull 600, 236.
Vol. 9, No. 6
(NHcM0.r SoluPer PER CENT tion Approx . cent Kz0 EXTRACTBD wt. Per Temp. Kr0 in -On Basis ofNO. used, G . cent O o C. Mineral Mineral Total KnO I . . . . . . . .. . . . . 0.15 0.5 20 8.40 1.68 20.00 2 . . . . . . . .. . . . . 0.15 1.0 20 8.40 1.67 19.98 3 . . . . . . . .. . . . . 0 . 1 5 1.5 20 8.40 1.87 22.26 4 . . . . . . . .. . . . . 0.15 1.0 40 2.20 34.00 6.47 1.0 40 5 ........ . . . . . 0 . 1 5 6.47 2.20 34.00 6. . . . . . . .. . . . . 0 . 1 5 1.0 40 6.47 3.73 57.65 7 . . . . . . . .. . . . . 0 . 2 0 1.0 40 6.47 1.55 23.96 8 . ....... . . . . . 0 . 4 0 1.0 40 6.47 1.75 27.05 1.0 40 9 . . . . . . . .. . . . . 0 . 6 0 6.47 1.65 25.50 10. ....... . . . . . 0.15 1.5 40 6.47 1.87 28.90 1 1 . . . . . . . .. . . . . 0 . 1 5 1.5 65 2.07 6.47 21.98 1 2 . . . . . . . .. . . . . 0.15 1.5 2.33 80 6.47 36.01 13. ....... . . . . . 0 . 2 0 1.5 80 2.95 6.47 45.60 14 ..... 0 . 4 0 1 . 5 80 6 . 4 7 2 . 8 0 43.28 15.. ........... 0.60 1.5 80 6.47 2.33 36.01 ... 1 ............. 0 . 2 0 1.5 65 7.78 0.25 3.23 2 ............. 0 . 4 0 1.5 65 7.78 0.13 1.68 3 ............. 0 . 6 0 1.5 65 7.78 0.08 1.03
MINER4 L Muscovite
........
..
ammonium sulfate was increased while t h e q u a n t i t y of muscovite a n d temperature remained constant, t h e differences in K 2 0 extracted were slight with n o straight increase with increase of concentration of ammonium sulfate. I n Nos. 4, j, a n d 6, where t h e conditions were approximately t h e same, there was absolute agreement between Nos. 4 a n d 5, with No. 6 very much higher. I n t h e case of Nos. 7, 8, 9 a n d IO, with t h e q u a n t i t y of muscovite variable a n d other conditions constant, t h e differences i n q u a n t i t y of K 2 0 extracted are not significant in view of t h e variation noted where t h e q u a n t i t y of muscovite was constant. T h e remaining tests, while suggestive of increased extraction a t higher temperatures, are suggestive only. Throughout this work t h e temperature control was approximate only a n d i t would appear from t h e results t h a t other factors are operative a n d not sufficiently controlled. T h e only conclusion t h a t stands o u t clearly is t h a t a t temperatures above 20' C. (room temperature) more K 2 0 is extracted b y this t r e a t m e n t . So far no results have been obtained throwing a n y light on t h e chemical changes involved or t h e process b y which t h e potassium is rendered soluble. DIVISION OF CHEMICAL INVESTIGATIONS BUREAU O F SOILS, W A S H I X G T O N , D. c.
1
LABORATORY AND PLANT NEW ALLOYS TO REPLACE PLATINUM By F. A. FARRENWALD Received May 1 1 . 1917
T h e development of materials t o t a k e t h e place of platinum i n m a n y of i t s applications has become not so much a m a t t e r of economic desire, as one of actual necessity. T h e present phenomenal activities i n chemical research a n d manufacturing enterprises have resulted i n a continually increasing consumption of this material, while statistics show t h a t t h e world's production has been on t h e decline. At t h e present time a n actual scarcity of metal is a matter of greater importance t h a n its consequent high cost. PRODUCTION-The following figures t a k e n from a report b y t h e United States Geological Survey, "Platinum a n d Allied Metals i n 191j," give estimates of production i n t r o y ounces during t h e period from 1912 t o 1915,for t h e principal mining countries of t h e world.
COUNTRY
Borneo and Sumatra.. ............
.........................
Canada Colombia ....................... New South Wales and Tasmania.. Russia .......................... United States..
.
..................
1912 200 30 12,000 778 300,000 721
1913 1914 2,000 50 30 15,000 17,500 1,275 1,248 250,000 241,200 483 570
...
1915
.. 100 18,000 303 12,400 742
During 1914,t h e United States imported platinum t o t h e extent of a b o u t j 5 , o o o t r o y ounces, a n d i n 1915 about 65,000 ounces. A n additional 65,000 ounces of new metal were recovered b y refiners of gold bullion a n d blister copper, while about 40,000 ounces of metal were derived from refining of various forms of scrap, chiefly from jewelry a n d dental work. MARKET-The price of platinum throughout a period of years has shown a steady increase, a n d there seems small likelihood of a near future r e t u r n t o greatly lowered quotations. T h e following figures give average prices per t r o y ounce for platinum ingots a t various times since 1874.
