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T H E J O U R N A L OF I I V D U S T R I A L A.YD E N G I N E E R I X G C H E X I S T R Y .
metals are present, each particular alloy is distinguished by a prefixed addition to the class name, for example, the so-called “Aich metal” would be termed “iron brass” and “manganese bronze” would be known as “manganese brass.” Bengough, in a paper on the “Properties of Alloys at High Temperatures,” gives determinations, through ranges of temperature up to their melting-points, of the influence of temperature on the breaking tensile stress and elongation of copper and aluminum, alloys consisting of ’a single, simple, solid solution (coppernickel, 70 : 30 brass), and alloys consisting of two solid solutions or other phases (Muntz metal; lorn-copper brass). I n every instance the author finds that the tensile strength diminishes as the temperature rises, although there is generally a change of direction in the curve representing this, most marked in the puremetals (copper, 650’ C.; aluminum, 395’ C.). Above these temperatures the metals resemble very viscous fluids, possessing little strength, being very ductile, and greatly influenced in their tensile strength by the duration of the application of stress. Stress also causes them to emit a cry like “tincry.” There are no thermal critical points a t these temperatures, and Bengough suggests t h a t in a pure metal the crystals are normally held together by Beilby’s “amorphous material,” stronger than themselves, in a more or less continuous sheet or cellwork, and that above the “temperature of recuperation” this is no longer capable of existing, and the crystals accordingly come in contact with one another. Fracture now occurs, no longer through the crystals, but along the crystal faces. When a metal is worked a t a temperature above the point of recuperation, “amorphous material,” if formed, cannot exist permanently, and no effect is produced on ‘the mechanical properties of the metal: this is “hot work.” “Cold work,” conducted wholly or partially below this temperature, produces “amorphous material” and strengthens the metal. Bengough shows the difference between rolled and cast material in strength by diagrams, and i t is seen t o vanish a t the temperature of recuperation. I n the‘case of pure metals, the elongation may increase, diminish, or remain almost constant, up t o the point of recuperation, but there it greatly increases, and remains high until near the melting point. Turner presents a study of the “Behavior of Certain Alloys when Heated in z~ucuo.” He has found t h a t zinc and other metals are entirely removed from brass and other copper-zinc alloys when the latter are heated in a vacuum. With brass, the separation of the zinc is quantitative provided-the temperature does not exceed 1200’ C. and the heating is not too prolonged. A sample of “poisoned” brass was subjected to this treatment, and i t was found t h a t all the zinc, lead and arsenic, and a little of the tin, were removed at 1200’ C. Zinc was readily volatilized from 60/40 and 70/30 brass a t temperatures of 520’ and 550’ C., respectively; and when “hard zinc,” the residue from galvanizing baths, containing about 5 per cent. of iron, was heated to 500’ C., in a vacuum, the zinc was completely volatilized, the iron remaining entirely in the residue. This paper is of great importance on account of the suggested application of the principle to the refining of crude copper, ’ brass scrap, hard zinc, etc.
SILOXIDE “Siloxide” is a name which has been given to products prepared by fusing pure anhydrous silica with oxides of elements of the silicon-carbon group, as titanium dioxide or zirconium oxide. The new glass is said to be formed by the solution of these refractory oxides of an acid character in silicic acid, and i t is stated to be more easily worked than pure quartz glassin fact, it can be worked by the ordinary methods employed in glass manufacture (see French Patent 432,786, July 31,
April,
1912
191I, of Wolf-Burckhardt and Borchers). 2-siloxide, or zirconium glass, and T-siloxide, or titanium glass, are now being manufactured a t Frankfurt a/M, Germany. While 2-siloxide and T-siloxide are said to lack the silky luster of quartz glass (“vitreosil”), yet it is stated [Thomas, Chew.-Zlg., 36, 25 (1912)]t h a t they possess distinct advantages over the latter with respect to strength, resistance to devitrification, and resistance to the action of alkalies. The best Z-siloxide with respect to strength is said to contain I per cent. of zirconia, while t h a t containing 0.5 per cent. has the most satisfactory thermal properties. It is said t h a t zirconium glass has a softening point not much different from that of quartz glass, but t h a t it resists deformation better at high temperatures because of its greater viscosity. The manufacturers state t h a t zirconium glass crucibles are far superior t o those made of quartz material in their ability to resist the action of “oxide-bearing metals” during smelting operations; t h a t zirconium glass can be used five or six times; and t h a t i t displays only in a very small degree the disagreeable property, inseparable from quartz material, of devitrifying a t temperatures exceeding 1300’ C. It is supplied in the form of tubes, slabs, concentrating vessels, crucibles, flasks, boxes, muffles, archedtubes, balls, calottes, etc. The titanium glasses (0.1to 2 per cent. of titanium) are said to have a somewhat lom-er resistance to compression than quartz glass, but t o resist transverse fracture better than the latter. The T-siloxide now being marketed is said t o be superior to even Z-siloxide x i t h respect t o thermal properties-to be more satisfactory when temperatures up to 1500’ C. are to be used. Its properties are said to be otherwise the same as those of 2-siloxide. While it is stated by the manufacturers t h a t zirconium glass may be had either transparent or opaque, no information on this point as to titanium glass was secured.
EXTRACTION WITH NAPHTHALENE. Naphthalene has been known for some time as a solvent for gums and resins (see, for example, English Patent, 14,554, June 30, 1903,t o Terrisse), and as a substitute for benzine and benzene, and similar solvents, for spreading purposes in the manufacture of rubber goods (see French Patent, 393,186, August IO, 1908, of the Rutgerswerke-Akt.). Qqite recently, a Magdeburg-Sudenburg, Germany, firm has placed on the market a plant for the extraction of bones, plants, fish residues, asphalt, etc., with naphthalene. . As is well-known, naphthalene is volatilized by means of steam; it is this property, in fact, which makes i t advantageous as a n extractive medium. Temperatures from the melting point, 80’ C., to almost the boiling point, nearly 218’ C., are said t o be applicable; and if this is correct, it is possible to work within wide limits. Further advantages are said to be that the solvent can be recovered from the solutions a t relatively low temperatures in comparison with other solvents with similar boiling points; that i t is not necessary to employ closed vessels with reflux condensers; and that the use of pressure, generally necessary for dissolving copals, may be dispensed with in the apparatus. The naphthalene extraction process is said to be particularly applicable for the extraction of bitumen, as “larger quantities of a product of higher melting point are extracted by naphthalene from asphalt-sand or Montan-wax than if one of the ordinarily known extraction substances is used.” In one test, 90 per cent. benzene was used, and 19 per cent. of bitumen with a softening point of 70’ was obtained; while with the naphthalene process, 23 per cent. of bitumen with a softening point of 81’was obtained from the same material in a shorter period. It is said that for the extraction of asphalt, the low price of the raw material is a consideration. I n addition, i t is stated t h a t no losses are
