T H E JOURNAL OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
May, 1922
DETERMINATION O F SULFURIC ACID MIST I N as-The gas is aspirated through a filter of well-carded, blue fiber, purified asbestos, the asbestos extracted with water and the extract titrated with standard alkali.
FIG.2
APPARATUS-An ordinary 1.25-in. filter tube funnel (see Fig. 3) with long stem, to permit a sample being drawn directly from the flue, may be used. If the gas is supersaturated with moisture it is advisable to use the form of apparatus shown in Fig. 4, the bottle serving as a condensing chamber t o avoid water condensation on the asbestos. Occasionally it is necessary to pass the gas through two such chambers to remove the condensed moisture from warm moist gases. The funnel is packed first with a layer of glass wool, followed by a two-inch layer of well-carded, purified, blue asbestos. and finallv a second laver of elass wool. The glass wool "prevents t h i asbestos plugging the inlet and exit openings. Perforated disks may be used in place of the glass wool. The asbestos is the blue African form. White asbestos will not give accurate results, as this is attacked slightly by dilute sulfuric acid and decidedly so by strong sulfuric. The blue form is not appreciably attacked, so that the acid may be extracted as free acid by water. The asbestos is purified by digesting with nitric acid, followed by a second digestion with hydrochloric acid. The material is now thoroughly washed to remove the acids and is dried. The dry asbestos is placed in widemouthed bottles until required. Before using it is carded or fluffed out by means of a pick and then placed loosely in the funnel to be used in the test. Asbestos Blue African White Canadian White Italian
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THE TEsT-The gas is aspirated through the filter at the rate of about 5 cu. ft. per min., the gas being measured by a dry gas meter following the apparatus. When a volume of 10 to 100 cu. ft. of gas has been aspirated, the amount depending upon the amount of acid mist present in the gas, the asbestos filter is placed in a beaker. (If SO2 is present in the gas, as is the case in contact sulfur gases, air is first passed through the asbestos to remove the SO2.) The tube is rinsed out, and the rinsings poured on the asbestos. The contents of the the beaker are now transferred to a 2-in. Buchner funnel in position on a half-liter capacity suction bottle. The water is drawn out of the asbestos and the filtrate passed
433
through the mat, thus formed, to remove the asbestos fibers. The mat is washed withsmall portions of pure water until free of acid, and the extract, transferred to a beaker, is titrated with standard alkali (0.05 N has been found to be satisfactory). Methyl orange is used as an indicator. DETERMINATION OF ARSENIC IN aas-The test is the same as the one described for determining sulfuric acid. An aliquot portion of the water extract is taken for a Gutzeit determination of arsenic. Arsenic in purified contact gas is carried in the acid mist. DETERMINATION OF CHLORIDES--~ portion of the water extract, obtained by the procedure described under the test for acid in gas and filtered through paper if necessary, is examined for chloride by the turbidity test by addition of nitric acid followed by silver nitrate reagent. Comparison is made with a standard using either Nessler tubes or a colorimeter. If the amount of chloride is too great for a turbidity test a gravimetric determination should be made, or the aliquot portion taken should be sufficiently diluted with water to enable the turbidity test to be made. The standard should contain the same amount of sulfuric acid as the sample. The extract should be free of asbestos fiber.
Liquid Oxygen Explosives Although the use of liquid oxygen explosives has not yet made much headway in the United States, experiments made with such explosives by a metal-mining company a t Pachuca, Mexico, operated by American capital promise quite satisfactory results, according to observations made by a representative of the United States Bureau of Mines. From the beginning of the entrance of the United States into the World War, efforts have been made by George S. Rice, Chief Mining Engineer of the Bureau of Mines, to haveliquid oxygen explosives tried out practically in this country. Owing to the fact, however, that no manufacturer in the United States makes oxygen liquefying plants, the use of these explosives in America has been quite limited. The development of this innovation so far has been largely German, and in Germany oxygen liquefying plants are manufactured in various sizes in complete units of apparatus and containers. Since the war the only extensive development outside of Germany has been in the Lorraine iron mines where the Germans installed apparatus, and additional apparatus has been put in by the French. One company in Lorraine is mining its entire annual output of 1,500,000tons of iron ore by the use of these explosives. This company has developed a cartridge of its own on which it has received patents, and has applied for others. It is claimed that the cartridge is an improvement on the German cartridge. The Germans use for brisant effects, soot; and for slow heavingeffects, wood pulp. Either fuse or electric detonators can be used for igniting the charge. The Germans have now developed a method of placing the electric detonator in t h e bottom of the hole in a special container and have been able to fire large rounds, it is claimed as high as twenty-eight shots a t a time
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FIG.4
Fastness of Dyes The National Council of Dyes and Colors held a meeting in Xew York City on March 20 and elected Mr. David N. Mosessohn of, the Associated Dress Industries of America, permanent chairman. The secretary, Dr. J. Merritt Matthews, proposed that something of a definite and concrete nature should be undertaken by the Council and proposed that each of the industries interested and associated with the Council should definitely formulate the various staple fabrics in which they are particularly interested and state what qualities of colors with respect to fastness or other properties should normally be expected on these fabrics, so that data would be available regarding the commercial requirements for colors on fabrics. As a result, a motion was passed instructing the secretary to write to the representatives of the various industries to secure definite data as t o the qualities of fastness required on the different staple fabrics and to present a report a t the next meeting of the Council if possible. It was also voted to distribute 4000 reprints of Mr. Haynes' report on certain tests made on colored fabrics..
