Two of the routine analyses performed on the uranium salts are the determination of oxides by refluxing with am-
monium oxalate solution and the determination of total fluoride content by pyrohydrolysis in platinum tubes
LABORATORY OF THE MONTH
N e w Laboratory Smooths Plant Start-Up Y ^ h e n Allied Chemical Corp.'s General Chemical Division brought its multimillion dollar uranium hexafluoride plant to full production recently, one of the major factors in effecting smooth start-up was the plant's $600,000 control and development laboratory. That it is operating smoothly is evident in the fact that the 10 millionth pound of U F e has recently been produced—and this with only about one third of AEC allowable impurities. Located at Metropolis, 111., the plant is the first privately-owned facility awarded a contract by the Atomic Energy Commission to produce refined uranium salt. The 7500-square-foot laboratory is devoted to analytical, control, and development functions, plus a library, two offices, and a dispensary. Stainless steel laboratory furniture is used throughout, not for the beauty it imparts, but to eliminate problems associated with uranium contamination. This includes the use of 19 hoods, three of them of the walk-in variety. A staff of more than 50 persons, 40 of them having college degrees or equivalent training, is used in performing the many types of analyses needed. The latter include laboratory control checks of the uranium as it passes through its various process phases;
analysis of the final product, which has a purity requirement better than that usually associated with a reagent grade chemical ; control of the gaseous fluorine process steps; and analysis of liquid fluorine. Aside from these needs, there are others which arise from the nature of uranium itself. Analyses carried out for health reasons involve air sampling, checking of effluent samples, urinalysis for uranium, and radioactivity surveys. To meet these needs effectively, the Metropolis Laboratory has fitted its air-conditioned building with a large array of the latest equipment available. In those cases where even the latest would not serve, the company's Morristown (N. J.) Research Laboratory was called upon to design and adapt the necessary instruments for Metropolis' peculiar requirements. Determinations in the near infrared are made with a recording ratio spectrophotometer. The I R spectrophotometer is used for accurate and rapid analyses in the multicell operations that produce liquid fluorine. An x-ray spectrograph is used to determine percentage of uranium in the various steps of uranium production, and a 3-meter 20-inch camera emission spectrograph is used to determine the majority of (he impurities in the uranium hexa-
fluoride as end product. Throughout all these processes, speed and accuracy are both essential, since percentage composition-limits critically affect all the steps in plant operation. Every effort was made in design and equipment to ensure smooth and efficient operation. Automatic titrators are used, for example, in determining the total hydrofluoric acid content of the potassium bifluoride melt in the fluorine cells. Metal lattice mounts are used for temporary laboratory set-ups. All control sections have their own a.c. line-operated pH meters and colorimeters. Recording densitometers are used to supplement the use of emission spectrographs. There are six semi-automatic balances and much other equipment for auxiliary use, such as a moisture monitor to improve the accuracy of moisture determination on uranium ores. Determination of uranium in the order of thousandths of a microgram is routine. The method used is based on the fluorescence of uranium. Consequently, one of the features of the new building is a separate laboratory containing only two fluorometers and an automatic calciner. This room has double doors and is equipped with its own air-conditioning and humidity control svstem. VOL. 32, NO. 9, AUGUST 1960
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91 A
Lab of Month The automatic recording freezing point apparatus is company-designed. The sample of uranium hexafluoride is melted in its nickel freezing point cylinder, and then placed in a constant temperature bath where it is cooled slowly until crystallization takes place. A thermistor is used as the sensing element. The cooling curve is plotted on the recorder
Much of the time required for quantitative separations is saved by use of the mercury cathode electrolysis instrument. Four of these are kept in daily use, removing interfering elements from uranium solutions •
The thermo balance is one of the pieces of equipment designed by General Chemical's Research Laboratory at Morristown, N. J. With its specially adapted Sartorius balance, this unit can process a uranium concentrate sample through the stages of reduction, hydrofluorination, and fluorination, recording all weight changes. It is extremely useful in setting up plant conditions
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