Dec., 1914
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T H E JOCRLVVdL O F I N D C S T R I A L A N D E , V G I A V E E R I N G C H E M I S T R Y
effect, but with the cooperation of the American chemist, the process is likely to play an important part in the American technology of beet sugar. H . C. MEYER FOOIE MINERALCo., PHILADELPHIA November 14, 1914
THE EFFECT OF STEAM UPON MAGNESITE BRICK OR CALCINED MAGNESITE Editor of the Journal of Industrial and Engineering Chemistry: Carbonate of magnesia or magnesite is found chiefly in Greece, Austria-Hungary, Africa, India, and in California in the United States. The deposits of Greece and California are of the white massive character and as a rule of very pure quality. They are not as suitable for refractory purposes in metallurgical processes as the Austro-Hungarian magnesite, on account of composition and high cost of preparation. The white magnesites are used principally in paper manuficture, in caustic form as flooring cement, and for the manufacture of carbonic acid gas, the carbonate as mined containing approximately 50 per cent of Con, which may be driven off a t a comparatively low temperature. A few refractory brick are made from white magnesite, but difficulties of manufacture and high cost render the demand very slight. It is with the Austro-Hungarian magnesite that the users of magnesite in this country are most interested. The material occurs in a crystalline formation and is gray in color with tinges of brown. I n comparison with the white magnesite it differs in composition and formation. The chemical composition is the most important difference. Comparative analyses of the two kinds of magnesite, calcined, are as follows: AustroHungarian . . . . . . . . . . . . . . . 2.75 . . . . . . . . . . . . . . . 0.50
Silica (SiOz) Alumina (AI? Iron oxide (FenOs) ..................... Lime (CaO). . . . . . . ...... Magnesia (MgO) , . ...... Loss on ignition.. . . . . . . . . . . . . . . . . . . . . .
7.00 2.50 87.00 0.75
White 2.50 0.25 1.00 2.25 93.00 1
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The impurities in the Austro-Hungarian render it less refractory, and it will frit more readily a t operating temperatures, which is a very important property, especially in open hearth steel practice in building the bottom and repairing the slag line. I n the calcined form, for commercial uses, Austro-Hungarian magnesite has a rich brown color and white magnesite is either white or a very light brown, depending on the thoroughness of calcination. The chief uses of magnesite brick are in open hearth steel furnaces, copper converters, reverberatories and settlers, and electric furnaces. Their use is spreading considerably where strong basic slags, mill cinder and strongly metallic slags are encountered, such as the bottoms of forging, heating and welding furnaces. It is an interesting fact, and one of importance to all users of magnesite, that when subjected to the action of steam, magnesite in calcined form, or even the most thoroughly burned brick, will hydrate, similarly t o the action of calcined lime when water is added. This hydration takes place t o equal degree in all brands of magnesite brick made in the United States or Europe. The effect of the hydration is disintegration t o a n almost impalpable powder. It does not seem to bear any relation t o the content of lime or other impurities, as the tests showed the same results for the Austro-Hungarian as for the white or very pure Grecian magnesite. Tests were conducted by placing brick in a steam-tight cylinder and subjecting to steam a t I O O lbs. pressure for a period of two hours, all brick tested showing hydration to the same degree, though it is reasonable t o conclude t h a t the action would be somewhat retarded under lower pressure or less severe conditions.
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Difficulties of this nature have been experienced in open hearth furnace bottoms by laying the brick and magnesite bottom over a bed of refractory materials mixed with water. Upon heating up, steam is formed and the bottom may be very badly damaged by hydration of the magnesite. This fact, which has not been well established until recently, no doubt accounts for a number of similar troubles which have occurred in years past. I t also explains cases of disintegration of burned magnesite brick which have been in contact with steam leaking from coils or steam-heated floors used in manufacturing magnesite brick. It should be made a matter of common knowledge, therefore, so that users of magnesite will be able to guard against trouble of this kind, especially during the initial heating period. R. H . YOUNGMAN HARBISON-WALKER REFRACTORIES Co. PITTSEIIJRGH, September 15, 19 14
CONVERSION TABLE FOR GLUES I n connection with the use of the Weinhagen Glue Hydrometer, which reads percentage by weight of air-dry glue, it is necessary to calculate the number of pounds of glue in a gallon of the dry product, as well as t o determine the capacity of tanks and other glue containers in terms of air-dry or bone-dry glue. I n determining the following values by experiment, a hide glue was used and the methods employed were of a degree of accuracy commensurate with technical use. The percentages selected are those generally dealt with in commercial glues. Per cent air-dry glue (Hydrometer) 0.0 0.5 1
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1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 13.0 13.5 14.0 14.5 15.0 15.5 16.0 16.5 17.0 17.5 18.0 18.5 19.0 19.5 20.0
Corresponding percentage bone-drv . d -u e 0.000 0.424 0.848 1.270 1.690 2.200 2.550 2.970 3.390 3.820 4.240 4.660 5.080 5,520 5.940 6,360 6.780 7.210 7,620 8.060 8.490 8.900 9.340 9.750 10.180 10.600 11.020 11.450 11.870 12.300 12.720 13.150 13.570 14.000 14.410 14.850 15.270 15.700 16.100 16.550 16.970
BAEDER,ADAMSON & Co. PHILADELPHIA, August 1, 1914
LBS. PER GALLONWHEN Air-dry 8.3360 8.3550 8.3650 8.3750 R...... . .iufin
8.3970 8.4080 8.4190 8.4300 8.4410 8.4515 8.4625 8.4730 8.4840 8,4950 8.5050 8.5160 8.5270 8,5380 8.5480 8.5590 8.5700 8.5800 8.5910 8.6015 8.6130 8.6230 8.6340 8.6450 8.6550 8.6660 8.6770 8.6880 8.6990 8,7090 8.7200 8.7310 8.7420 8.7530 8.7640 8 7740
Bone-dry 8,3360 8.3570 8.3690 8.3810 8 3930 8,4060 8.4190 8.4320 8 4440 8.4570 8,4700 8.4820 8.4945 8 .. m o
8.5210 8.5330 8.5460 8.5590 8.5715 8.5840 8.5970 8.6100 8.6225 8.6340 U. 6460 8.6600 8.6715 8,6840 8.6970 8.7100 8.7225 8.7360 8,7490 8.7610 8.7740 8,7870 8,8000 8.8130 8.8260 8.8390 8.8520
ISMAR GINSBERC
CAP FOR BUNSEN BURNER USED WITH NATURAL GAS Editor of the Journal of Industrial and Engineering Chemistry: Special burners adapted for natural gas are already in much use. But Bunsen burner and other modifications of this can be rendered serviceable for natural gas by providing caps made of ordinary wire gauze, say about 2 2 mesh. A cap made of wire gauze and put on a Bunsen burner or this type of burner gives a steady flame, not extinguishable even by a strong air draught. Such a cap can easily be made by pressing a piece of
