Apr.. 1913
T H E JOL-Ra\-.4L OF I.\-DYSTR19L
from I O per cent. t o 1 . 2 5 per cent. so t h a t the detection of even three per cent. of asphalt is made possible b y the method of fractionation which has been employed in this work. The 3 1 j O C. t o 350’ C. fraction did not give the slightest trace of insoluble products. CONCLUSION
While the above results do not give any absc.lute idea of either the amount or exact nature of the material which has been fluxed with the t a r , the authors feel t h a t the improvement which they have made upon former methods may still prove of value, until a more exact method shall be forthcoming. Specifications for tar-oil or tar-asphalt mixtures will be useless without some method of checking up the material submitted under them. We now think it possible, however, by specifying t h e grade and character of both the t a r and petroleum or asphalt product t o be used, and then obtaining d a t a on similar laboratory mixtures. t h a t we can determine with reasonable certainty whether our specifications are being fulfilled. I n order t o more closely determine the character of the material which has been fluxed with a tar. a volatilization test in conjunction with the dimethyl sulfate test will no doubt prove of great importance, and we feel t h a t some accumulated data on these two tests will place us in a much safer position for specifying and identifying bituminous mixtures which present such difficulty t o the chemist. 1-
s
PUBLIC ROADS WASHINGTON. D. C.
OFFICE O F
T H E DETERMINATION O F OXYGEN I N METALLIC TUNGSTEN POWDER AND SOME NOTES ON THE DETERMINATION O F OXYGEN I N STEEL B y CHARLESMORRIS
A*YD E.VGINEERIA’G C H E - V I S T R Y
295
gen in steel; i. e . , the ignition of the substance in a stream of hydrogen, which method is credited t o Ledebur. The electrically heated furnace introduced b y the author‘ in 1908 for the direct determination of carbon in iron, steel and alloys is utilized in the process which is described in detail in this paper. Walker and Patrick,’ in a paper read at the Eighth International Congress of Applied Chemistry, attack the accuracy of the Ledebur method on the ground. t h a t any oxides of manganese or silicon present in the steel would not be reduced. The author regards the Ledebur method as more practical t h a n the proposed new one2 above noted; even if the former process does not reveal the total oxygen present, i t certainly shows enough of i t t o furnish a basis for judgment of t h e quality of the steel. If the steel is sufficiently dirty and poorly melted in actual openhearth Bessemer or crucible practice t o contain oxides of manganese and silicon, then it would surely contain enough oxide of iron t o condemn i t . .4 P P A R A T U S
The arrangement of apparatus is indicated in t h e drawing and the accompanying notes. The towers (or jars) are the author’s design as are also J , I and C, and were first used as part of a combustion train.3 I n this laboratory four furnaces are placed side by side. By the use of a P tube at t h e outlet of jar F, one train from F t o E: can be made t o serve two furnaces. Of course a separate set of A, B and C is necessary for each furnace. If, after making a large number of determinations, the blank begins t o show a gradual increase, the contents of the various jars must be renewed.
JOHNSON
Received January 22, 1913
11E T H 0 D
I t has been found a distinct advantage both in the manufacture and use of tungsten powders t o know their oxygen content. In one of t h e laboratories
Blank.-Before introducing anything into the electric furnace, close all points marked “screw pinch cock.” At B make a connection with a straight
APPARATUS A-Ignited asbestos and dry stick KOH. B-Glass wool plugs and PzO:, (anhydrous powder) C-Solution of K O H . D-A clamp t o prevent the quartz tube from moving since it was found t h a t results \-aried if the tube moved back and forth. E-Quartz tube. F-Ignited asbestos and P205 in alternate layers. G-Ignited asbestos and dry stick KOH in alternate layers.
under the author’s direction. this determination is a matter of daily routine. The method involves the‘same principle used in the determination of oxy-
H-Asbestos and small lump (size of pea) CaC12 in alternate layers. 1-50 cc. alkaline solution of pyrogallic acid, 5-50 cc. KOH solution. K-Kipp generator ( 2 quart) SOLUT~OSS Potassium hydroxide: 1 gram KOH t o 1 cc. water. Pyrogallic acid: 3 grams pyrogallic acid and 2 cc. water to 3 cc. * KOH solution. Kipp Generator: Use stick zinc and dilute hydrochloric acid ( 1 : 1 ) .
glass tribe instead of the 1
u
tube shown.
Insert
J . A m . Chem. SOC., 30, i73. Proc. 8th Intern. Cong.A p g l . Chrm.,21, 139; alsoTHIs JOURNAL, 4, 799. J . A m . Chem. SOC.,28, 8 6 2 .
296
quickly into the quartz tube ( a t the point marked E ) the porcelain boat t h a t has been kept a t 1 0 j O C. in a n air bath. Push the boat into the center of the furnace with a heavy copper wire which is marked to show how to place the boat in the hottest part of the furnace. Stopper the tube as quickly and tightly as possible. Open all four pinch cocks and turn on the hydrogen slowly until i t passes through the apparatus a t the rate of about seventy (70) bubbles per minute. Allow the hydrogen to pass shrough the cold furnace for thirty minutes. Close all the pinch cocks a n d replace the glass tube a t B by the U tube. Open all cocks and let hydrogen run for another half hour t o fill the weighing apparatus with this gas. Close all pinch cocks and the glass cocks on the U tube. Remove the TJ tube and weigh i t quickly. Insert the U tube again, open all cocks and start the hydrogen flow: t u r n on the electric current in the furnace and bring up the temperature to 9 j 0 - 1 0 0 0 ° C. After reaching this temperature keep the heat on for two hours with the hydrogen passing continually. Close all pinch cocks, shut off the hydrogen, and close Dethe glass cocks on the weighing apparatus B. tach and weigh B . The difference between this weight and the first weight represents the blank to be deducted from all determinations. Sanzp1e.-Dry the finely ground powder of the tungsten metal t o constant weight a t 105' C . P u t two or three grams of the powder into a porcelain boat t h a t has been dried a t r o j o C. Place this in the cold furnace and stopper tightly a t E . Using the glass connection a t B, open the pinch cocks and allow hydrogen t o pass through the cold furnace for one-half hour to remove whatever air entered when the charge was inserted. Close all pinch cocks and replace the glass tube by the weighed U tube a t B. Open all cocks, adjust the hydrogen flow t o 7 0 bubbles per minute and turn on the electric current, heating the furnace to 9 j o - 1 0 0 0 ~ C. Maintain this temperature for two hours with the hydrogen passing. Close all cocks and turn off the hydrogen. Remove and weigh the U tube. The increase in weight minus the blank gives the amount of water formed by the reduction of the metallic oxides to metal. This result multiplied by 16 and divided by 18.016 is equivalent t o the weight of oxygen which is c6nverted into percentage by the usual calculations. S T A K D A R D I Z AT I O S 0 F .IP P .\ R .\ T US JVITH c . P. T U N G S T I C oxIDE.-This material is prepared as follows: Treat five grams of 96-98 per cent. tungsten powder in a platinum dish with I O cc. C. P. hydrofluoric acid. Pour on this mixture very slowly 30 cc. of concentrated nitric acid. This produces considerable heat, and the material is dissolved as clear as water. Now add I j cc. of concentrated sulfuric acid, evaporate to thick fumes, cool, add I O t o 2 0 cc. c. P . hydrochloric acid, boil three to four minutes, a d d j o cc. of water, heat, filter, and wash free from iron and sulfates by decantation in a 600 cc. beaker. Transfer to a platinum dish, ignite a t a bright red heat in a muffle, a n d put in a glass-stoppered bottle. Before using a n y of this material for a test, ignite a portion
of i t a t a blast-lamp temperature. Immediately after the blasting put one gram of the oxide in a porcelain boat dried a t 105' C., and charge i t a t once into the furnace. I t will require a t least six hours treatment a t 9j0-1000° C. to reduce this amount of oxide and carry all of the water formed over into the weighing apparatus. W I T H F E R R I C oxIDE.-~isso~ve I O grams of lowcarbon steel of very low phosphorus, sulfur and silicon content in roo cc. hydrochloric acid in a liter beaker. Transfer this to a No. 7 porcelain dish and evaporate to I O cc. Add I O O cc. nitric acid and evaporate t o 20 cc. Add j o cc. of concentrated nitric acid. and evaporate to dryness. Place the dish in a muffle and heat to redness. Cool, dissolve in j o cc. hydrochloric acid, add j o cc. of water ; evaporate to small volume, filter out insoluble matter. such as silicic acid, and precipitate with filtered ammonia. Wash t h e precipitate b y decantation until free from chlorides, dry in a porcelain dish, heat t o redness, and place in a stoppered bottle. Blast a portion of this for three or four minutes, transfer I gram quickly t o a porcelain boat, and place a t once in the reduction furnace. Pass hydrogen for six hours after the furnace reaches 9 j 0 - 1 0 0 0 ° C. TABLEI-RESULTS
OBTAINEDBY APPARATUS DESCRIBED
Pure WOa. 1 gram gave 0 . 2 5 0 gram gave 0 . 5 0 0 gram gave
2 0 . 69 20.70 2 0 80 20 3 0
per cent. oxygen per cent. oxygen per cent. oxygen per cent. oxygen
~
Average. 2 0 6 0 per cent. plus Pure FezOs, 30.05 per cent. oxygen 0 , 5 0 0 gram gave 3 0 . 1 6 per cent. oxygen Blanks, 0 0030 and 0 0 0 3 6
THE
OF
EFFECT
FREE
CARBOS
OS
THE
METHOD
I t is a n advantage t o have some excess of free carbon in finished tungsten powder, and, a t times, in the process of manufacture, it is necessary to know the amount of oxygen present in a powder t h a t contains as much as three or four per cent. of charcoal. Some tests were made to see if the reaction WO, + 3C = W 3CO might not occur a t the same time with the de6H = W 3H,O. Table I1 sired reaction WO, shows t h a t the presence of excessive amounts of free carbon caused no material error in the case of the pure tungsten oxide, but did cause low results when the carbon content exceeded five per cent. in the iron oxide. A curious feature is t h a t thirty per cent. of free carbon caused practically no lower result than the addition of ten per cent.
+
+
TABLE 11-RESULTS OBTAIXED Grams of mixture _ _ h -
U'Oa 0 0 0 0
Charcoal
+
OXIDES AND CHARCOAL Percentage Percentage Carbon Oxygen found present
WITH >fIXTURES O F
Percentage Oxygen theore tical
0 060
20.69 20.69 20.69 20 69
2 0 57 19 .SO 20.32 20 5 3
26 23 16 10
0 0 0 0 0 0
30.05 30.05 30.05 30.05 30 05 30 0 5
2 v . n ~
None
27,35 28.68 27 53 29.95 27 . 3 2
30 5 23 3
544
0 201
300 400
0 090 0 080
500
6 0 7 7
Fez03
o
5785 473 400 300 500 0 500
0 0 0 0
000 208 122 089
025 050
23 0 4 7 9 ;
Apr
~
19i3
T H E JOL-RIVAL OF I,\-DL-STRIAL
A N D E-YGISEERI-YG CHE-IIISTRE-
’97
The following table shows the amounts of oxygen found in t h e various brands of tungsten powders made both in t h e U. S.and abroad. Each numeral represents a different make.
THE DETERMINATION OF PHOSPHORUS I N FERROTUNGSTEN, METALLIC TUNGSTEN POWDER, TUNGSTEN OXIDE AND TUNGSTIC ACID BY DIRECT SOLUTION
The reduction was particularly poor in the second ‘lot received from the German manufacturer designated as I1 ( N o . z in his second shipment). When so much oxide is present i t can be easily detected b y t h e eye, being equivalent t o 10.92 per cent. of tungstic oxide. Such so-called metal has a distinct brown color.
The author found in the course of an investigation t h a t the practice of decomposing tungsten-bearing materials by fusing them with a mixture of sodium carbonate and potassium nitrate, leaching out t h e fusion, acidulating with hydrochloric acid, removingthe tungstic acid by several evaporations t o dryness, and then using the filtrate and washings from t h e tungstic acid for the determination of the phosphorus, gave f a r less of t h e latter element t h a n was actually present. He then devised the following method which he has found t o give near enough t o the true phosphorus for technical purposes.
TABLE111 Imported or domestic
Oxygen found Per cent. Consignment
German German German German German American hmerican American American american .-2merican American THE .4
DECARBOSIZATIOK
OF
1 02
..
1.10 2.26 0 18 0 53
so. 1 No 2
0.37
No. 1
0.47 1 24 0 80 0 45 0.08 0 07
?io. 2
STEEL
..
.
....
F ERR 0 - T US G S T E S .
,.. . , . . . .. .
..... IGSITED
IK
STREAM O F HYDROGEK FOR T H E O X Y G E N TEST
I n 1909 the writer called attention t o the fact t h a t hydrogen will produce a bark, or decarbonized surface, on steels when the latter are heated in a current of this gas. Supplementing this statement’ t h e following tests were made on three steels t h a t were analyzed for oxygen: TABLEIV Percentage carbon Grams of content m drillings taken No. of hours 7 for the ignited in, Before After oxygen test hydrogen ignition ignition ?ample I . , . . . 9 6 3’i2 1.04 0.90 Sample I1 . . . . . 1 6 . 0 3’/2 1.08 0 83 Sample111 . . . . . 1 9 . 5 3’/2 0.83 0 io
I n the foregoing method, no preheating furnace or tube is used such as was recommended b y Ledebur in his ‘
