INDUSTRIAL AND ENGINEERING CHEMISTRY
116
and a stream of water run into the crucible to remove the soluble slag. It was found that the uranium had fused into one mass, which was somewhat brittle and hard and not easily worked. A careful analysis made by the highly trained chemists of a reputable company gave the following results: Uranium Iron Carbon Oxygen
Silicon Calcium Aluminium
99.31 0.57 0.09 0.03
None None Trace
This analysis showed the presence of iron and carbon in objectionable quantities. An examination of the products used indicated that cab cium was the source of these impurities. Therefore, to elim-
Vol. 18, No. 2
inate these substances, the calcium was carefully sublimed before using. While the sublimed calcium itself gave practically no test for iron, the residue contained much iron and carbide. A similar reduction to the one last described was made using sublimed calcium, with the result that a mass of uranium weighing 1500 grams was obtained. I n general, the product resembled the first one except that the ingot possessed a convex surface, was very silvery, and clean, and showed fine crystalline markings. A careful determination showed the iron content to be less than 0.01 per cent. This same process has been applied with success to the preparation of zirconium, beryllium, and thorium, and plans are being made to test it on vanadium, hafnium, etc.
Effect of Sulfur in the Briquetting of Subbituminous Coal' By H. K. Benson, J. N. Borglin, and R. K. Rourke UNlVER5ITY
OF
WASHINGTON, SEATTLE, WASH.
MONG the subbituminous coals of the State of Washington are some that are more commonly designated as lignites owing to the property of "slacking" or disintegration by weathering. This characteristic has limited the commercial use of such coals and has stimulated experimental studies seeking modifications of structure tending toward greater permanency in form. I n this class is the coal mined at Tono, Washington. It is black in color, with a brown streak, is slightly banded in structure, and breaks with a conchoidal fracture. The proximate analysis of the coal is given in Table I.
A
Table I-Percentage
Composition of Tono Coal Laboratory sample Air-dry Pure coal air-dry Per cent Per cent Per cent
C A R SAMPLE'
As received Per cent Moisture 20.2 14.5 Volatiles 31.5 33.5 Fixed carbon 39.9 43.9 Ash 8.4 9.05 Sulfur 0.52 0.56 Nitrogen 1.06 1.14 B. t. U. 9280 9940 a U.S. Geol. Survey, Bull. 474, 75.
44:i) 56.0 0:?3 1.49 13,000
12.3 40.8 39.8 7.1 0.3 1.60 9650
I n a previous investigation2 it was found that the maximum yield of by-products was obtained upon distillation of a retort temperature of 380' C. Approximately 5.5 per cent of low-temperature tar, 54 per cent of solid residue, together with 4400 cubic feet of gas were obtained. The residual coal, aside from a slight silvery luster, was not changed in appearance. Its proximate analysis was as follows: Moisture Volatiles Fixed carbon Ash B. t. u.
Per cent 0.00
14.00
73.00
13.00
12,710
but its physical form was not more favorable for commercial purposes than that of the original coal. I n the present study an attempt was made in a preliminary way to modify the structure of Tono coal, so that its fuel values and its form and structure might alike enhance its commercial use. Attention was directed to the action of sulfur as a temporary intermediate agent in the coking of coal, and various mixtures of sulfur, asphaltic binder, and Tono coal were heated to 700'-950' C. for the purpose of forming a coke-like mass. Experimental The coal was ground to pass 20 mesh and then mixed with pulverized, crude sulfur in varying proportions. This mixture was then poured into molten asphalt obtained from a local briquetting plant, thoroughly stirred until a uniform plastic mass was obtained, and then compressed in a hydraulic press into briquets 3 cm. (1.25 inches) in diameter and 5 cm. (2 inches) long. The briquets were carbonized in cast-iron retorts for 8 hours at temperatures of 700" to 950" C . Some runs were allowed to cool in the retort while others were quenched with water.
Experiment I Run
Table 11-Sulfur and T o n o Coal Sulfur in Sulfur in mixture residue Per cent Per cent Temperatwe, 700' C.
1.95 4.75 8.52
9.10
REMARKS
3.57 6.80
The general effect of low-temperature distillation resulted in an increase of approximately one-third in heating value,
To ascertain the effect of the asphaltic binder, briquets containing 5, 10, 15, and 35 per cent, but no sulfur, were carbonized under the same conditions as above. The residue crumbled under pressure between the fingers.
1 Presented by H. K. Benson and J. N. Borglin before the joint session of the Division of Petroleum Chemistry and the Section of Gas and Fuel Chemistry a t the 70th Meeting of the American Chemical Society, Los Angeles, Calif., August 3 to 8, 1925. Benson and Davis, THISJOURNAL, 9, 946 (1917).
To ascertain the effect of briquetting, a batch was divided into two parts, one distilled unbriquetted and the other briquetted. (Table 111)
*
Experiment II
Table Ill-Sulfur.
'l'ono Coal. and A s o h r l t
without alxuion wliile those csrironiacii without sulfur xerc readily (lisint.egrated ! ~ yslight prcasurc. The lower temi)eratiire of eiirl~oriizritioii-i. e., at 700" C.did not seein to alfcct the cliaraeter of thc rcsidne either in i t s sulfur content or in its physical properties, i~rovidedtlic carbonizat.ion was carried to coinplction Ttie effect of quenching wzs very evident ill the r('ductioii of sulfur content nf the rcsiduc. Theoretical Discussion
E.cperinzent 111 The cfrect US varyin:: the iiriginal cimbcnt of sulfur wit11 approximately thc sann? ijiiantity of himlei is s111iw11 i n Tablr IV. 'fhllle Lv--S"lf"r
Content of Coke
Tlie crperiineotal work above noted is iiot sufticiently exliaustive in character t o permit definite conclusions, and the inve4igntiini is being uorrtiiiued i n tlic form of a sulfur survey of rrll t,he prwluetti of carlmiioation. A number csp1:mLtions iiriglit., hirwcrer, be adv;ii1i:cil ti, rrccount for the cuhiirg effects.
S111i111 i n
Ih
