Nov.,
I913
T H E J O U R N A L OF IATDUSTRIAL A N D ENGINEERING C H E M I S T R Y
and trolley transportation. The plant operation requires nothing in the way of special experience, skill or supervision. Raw materials are always a t hand and the success of briquetting is independent of special conditions of the flue dust. I n the Scoria process no air drying is necessary and this distinguishes it from all other briquetting processes. Savings in space and handling are also considerable factors in its economical advantages. The hydraulic binder gives the body the necessary consistency a t a minimum consumption of binding material, and, being in the nature of a hydrosilicate, leaves the oxides freely accessible to the top gases. It is not necessary in the case of the Scoria binder to have enormous pressure on one side of the briquette to produce a n actual flow of gas through the structure. Also the temperature necessary for the destruction of the hydrosilicates is above t h a t where sintering commences, so that there is no possibility of the briquettes crumbling away prematurely. I n practice, a very important coke economy will result from the use of the Scoria process. Working with a homogeneous and naturally piled stock column, gases can circulate and pass up under equal pressure, while combustion will be far more complete and the production of carbon monoxide will be lessened; i t has been proved by actual operation in Germany that a saving of from 15 to 20 per cent of coke has been effected. The inventor of the process feels confident t h a t it is quite possible to perfect operating conditions so as t o produce one ton of iron per day for every cubic meter of blast-furnace volume. The Scoria plant may be used to produce excellent slag building brick, and could alternate their manufacture with the production of flue-dust or fine ore briquettes a t a moment’s notice, the operations being almost identically the same, except that the flue dust or fine ore is left out of the mixture. Such bricks have shown ample strength for all purposes, not only under severe laboratory tests, but also in actual use for building purposes during a number of years. Cost of production (not counting the slag as having a value) in Germany, on a two-press installation capable of furnishing 24,000,000brick per year, is about $1.25 per thousand. -__
EXPOSURE TESTS OF COPPER, COMMERCIAL ALUMINIUM AND DURALUMIN A paper on the above subject, read by Prof. E. Wilson, before the British Association a t Birmingham, described a continuation of tests upon the influence of exposure in London on the electrical conductivity of light aluminum alloys, reports of which have been made from time to time. Each specimen is in the form of wire 0.126in diam. and 70 feet long. After two years’ exposure, the percentages increase of electrical resistance taken on the values in 1911a t 15’ C.are as follows: High conductivity copper . . . . . . 2.0 Commercial aluminum.. 4.4 Duralumin. ................................ 8.2
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Duralumin is a copper-manganese-magnesium alloy of high tensile strength and exposure has apparently made it more brittle. ELECTROLYTIC COATING OF IRON AND STEEL WITH LEAD According t o The Electrician for September 26, 1913, a n English company has acquired a process devised by Mr. Sherard Cowper-Coles for coating iron and steel with lead electrolytically. It is stated that lead can thus be economically deposited up t o a thickness of one-eighth inch, and that the method is suitable for protecting iron and steel from corrosion, and for the lining of pipes, tubes and chemical vessels for containing corrosive liquors. Steel plates coated by this process are much smoother than the ordinary terne plate and there is no reduction in tensile strength or ductility. The process can also be used for the
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coating of earthenware and wood and for the protection of ornamental iron work. The cost is stated to be low. TANNIC ACID FROM SPENT SULFITE LIQUOR According to T i d s k r i f t for Papirindustri as reported in Paper 13, h-0. 4, 23 (Oct. 8, 1913),Hans Lundmark, Drammen, Norway, has succeeded in reclaiming tannic acid suitable for tanning leather, from waste sulfite liquors. The acid ought, however, to be used only in admixture with some other material, as i t is said the tanning process then takes less time. The tannic acid from waste sulfite liquor is said to be very cheap. Some important tanneries in England are now trying out this acid. Mitscherlich and other chemists have, as is generally known, experimented considerably with the preparation of tanning material from the above source, but with indifferent success.
A NEW DESULFURIZING METHOD The Engiizeering and Mining Journal, July 5 , 1915, describes the Hall process of desulfurizing sulfide ores with eradication of noxious smelter fumes as entirely novel, being based upon the principle of removing the “fixed” sulfur atom of a sulfide by distillation, without permitting any considerable portion of the sulfur thus discharged to pass into any combined forms, such as SO%or SOa. The distillation of both fixed and free sulfur as such constitutes the advantage this method has over the other sulfurrecovery processes. Eliminating the sulfur as oxide with subsequent reduction means t h a t a large amount of free oxygen must be taken care of before the sulfur reduction begins, thus requiring extra expense for reducing agents, while the fuel expense of removing oxygen combined with sulfur from such association is greater than the fuel expense of direct distillation. Tests have been made to determine how complete a desulfurizing could be produced in this process; many analyses show less than I per cent of total sulfur remaining in the cinder. The distillation is obtained by the direct application to the ore of a burning gas flame of slightly reducing or, a t least, non-oxidizing character, accompanied by Hg0, either in the shape of water of formation (from the combustion of hydrogen) or of extraneous water in the shape of steam which is decomposed by the hot ore. The nascent oxygen goes t o the metal and the nascent hydrogen combines with any free oxygen t h a t may enter the furnace by means of the atomizer through which the gases are admitted, thus creating a sort of cycle of H20 decomposition and water formation from the combustion of the hydrogen so derived. When the furnace burners are properly adjusted, the final discharge of hydrogen appears to be all in the shape of water vapor, i. e., complete balances are easily maintained so that there is substantially neither SO?, SOS, COS nor HzS in the discharge, tests being made on samples taken within a distance of six inches from the furnace. A large variety of ores have been worked, including pyrites, various pyrrhotites, copper concentrates, crude blende and zinc concentrates. The action appears to be the same on each. I n order t o prove that the “fixed” atom is removed by distillation, the furnace has been operated on chemically pure FeS; no SO2 or H2Swas discernible in the discharge, but only yellow elemental sulfur vapor. The analyses of the cinder show it to be a mixture of FegOs and Fe304. The temperature maintained in the furnace must be slightly above 700’ C., as that is about the distilling point of the sulfur of a metallic sulfide, and it must be maintained below goo’ C., the fusing point-a large margin of safety. Although undoubtedly the reaction is somewhat exothermic, no allowance has been made for this in the fuel calculations, fuel required being calculated as if the reaction were entirely endothermic; on such a basis, allowing amply for radiation
