INDUSTRIAL AND ENGINEERING CHEMISTRY
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teated. The velocity at impact and the rate of bending of the eamples are reasonably constant. LITERATURE CITED
(1) Chatten, C. K.,Eller, 9. A., and Werkenthin, T.A., Rubber Age (N. Y.), 54, 429 (1944). (2) Forman, D.B., paper presented at April, 1944,meeting of Division of Rubber Chemistry, A.C.S., New York. (3) Garvey, B. S.,Jr., IND. ENQ.CIEM., 34, 1320 (1942).
Vol. 16, No. 9
(4) Graves, F. L., and Davis, A. R., India Rubber World, 109, 41
(1943). (5) Kemp, A. R., Malm, F. S., and Winspear, G. G., IND.ENQ. CHEM.,35, 488 (1943). (6) Martin, 9. M., Rubber Age (N. Y.),.52, 227 (1942). (7) Morris, R. E., James, R. R., and Werkenthin, T. A., IND.ENQ. CREM.,35, 864 (1943). (8) Selker, M. L.,Winspear, G. G., and Kemp, A. R., Ibid., 34, 157 (1942). PRESENTED before the Division of Rubber Chemistry, AMERICANCHEMICAL SOCIETY, at its New York meeting.
Monel Metal Pouring Plate for Silica Fusions R. S. YOUNG, Rhokana Corporation,
I
N MAKY analytical laboratories, particularly in the mining and metallurgical industries, a large number of silica fusions are carried out daily. These are usually made in platinum crucibles or dishes, using sodium carbonate or a mixture of carbonates as a flux. Fusion may be made on the sample directly or on the insoluble portion after prior acid treatment.
L$m*y,f -A, Figure 1.
Pouring Plate
Since these determinations are generally used for control purposes, speed is essential. If the fusion is allowed to solidify in the crucible, a long time is required to dissolve the contents in the dilute hydrochloric arid usually employed. The practice of allowing the melt t o cool on the sides of the crucible requires careful manipulation, and even then most of the sample solidifies at the bottom. When solution of the solidified melt is slow, more hydrorhloric acid is often added to hasten the action. However, as the resulting solution usually must be evaporated to dryness to remove silica, the increase in bulk prolongs the evaporation period. When a fusion reacts slowly with acid, or adheres to the crucible, there is a temptation t o hasten solution by scraping with a glass rod, which usually results in ultimately deforming or injuring the platinum. The time lost in waiting for cooled fusions in platinum crucibles t o dissolve is particularly important t o those laboratories where a n abundant supply of platinum ware is not available. This difficulty can be overcome by pouring the molten fusion into a depression on a Monel metal plate. The material quickly solidifies in the form of a flat button which is transferred with platinum-tipped tongs to a beaker or casserole, together with the platinum crucible. A few milliliters of dilute hydrochloric acid suffice to dissolve the thin film of solidified melt left in the platinum crucible or dish, which can be washed and removed for another fusion in a minute or two. Owing to its surface, the button rapidly oes into solution in dilute acid. The chilling effect produced %y pouring on the Monel plate gives a product which dissolves more readily than a fusion allowed to cool in the crucible. If necessary, solution of the button may be aided by breaking up with a flat-tipped glass stirring rod. This procedure was first brought t o the writer’s notice some time ago in the laboratories of the International Nickel Company of Canada a t Copper Cliff, Ontario, where i t had been in use for many years. It has since been applied successfully t o a wide variety of products.
Limited, Nkanr, Northern Rhodesia
The plate is illustrated in Figure 1. Molten sodium carbonate under these conditions has no effect on Monel metal. Plates are still in perfect condition after hundreds of thousands of fusions have been poured on them. Tests for copper and nickel with pure carbonate fluxes have shown that the quantities of these elements picked up from the plate are below the limit of quantitative determination. The extreme resistance of Monel to molten sodium carbonate does not extend to peroxide or bisulfate, and fusions of the latter should not be poured onto such a plate. The Monel plate can be cleaned and polished occasionally with any standard metal cleaner and rinsed thoroughly in water t o remove traces of polish. The plate illustrated in Figure 1 is intended for general analytical work where 0.5- to 2.0-gram samples are fused with 5 t o 10 times their weight of carbonate flux. Where other quantities are employed the size of the depression may be altered slightly. The object should be the formation of a slightly rounded button which will fill the depression but not overflow to give a thin layer on the plate. I n the latter case the thin edge of the button may break in several pieces when picked up with the 4 slightly larger plate t o contain two rows of depressions tongs. . may be used where a large number of fusions are carried out as routine determinations. Remove the crucible from gas burner or electric furnace when contents have fused, pour onto plate, place crucible on Transite or Alberene stone table top or on the plate itself, pour the next crucible, place the first solidified button in the corresponding crucible, and transfer to beaker or casserole. It is not ood gractice to put a red-hot platinum crucible on a Monel pyate, ut after the crucible is poured it is almost invariably cool enough to place directly on the plate beside the button if desired. Tip the button from the c,rucible into the beaker and add a little dilute hydrochloric acid to the crucible. Continue pouring in this manner, wash, and remove the crucibles. While the main portion of the fusion contained in the button is dissolving, the platinum crucibles or dishes may be used for further fusions.
Spectrophotometry Two papers have been prepared by the Research Department of the Calco Chemical Division, American Cyanamid Co., and are available through the Advertising Department, Bound Brook, N. J. “Spectrophotometry and the Colorist”, Calco Technical Bulletin 756, prepared by E. I. Steams, discusses interpretation of spectrophotometric data and suggests methods of application to mill production and research problems. “Identification of Organic Pigments by Spectrophotometric Curve Shape”, Calco Technical Bulletin 754, prepared by R. Abbott and E. I. Stearns, illustrates the general method of approach to the problem of identification of organic pigments by their characteristic absorption curve shape.
