^7:22 ^^.ASSIFIED UNCLASSIFIED BNL-2396 Subject Category: CHEMISTRY UNITED STATES ATOMIC ENERGY COMMISSION NOTES ON THE EFFECT OF MAGNESIUM ON PROCESSING By J. Weisman ■sh \ December 7, 1954 Brookhaven National Laboratory Upton, New York Technical Information Service, Oak Ridge, Tennessei Work performed under Contract No. AT-30- 2-Gen-l6. Date Declassified: November 16, 1955* This report was prepared as a scientific account of Govern- ment-sponsored work. Neither the United States, nor the Com- mission, nor any person acting on behalf of the Commission makes any warranty or representation, express or implied, with respect to the accuracy, completeness, or usefulness of the in- formation contained in this report, or that the use of any infor- mation, apparatus, method, or process disclosed in this report may not infringe privatelyowned rights. The Commission assumes no liability with respect to the use of, or from damages resulting from the use of, any information, apparatus, method, or process disclosed in this report. This report has been reproduced directly from the best available copy. Issuance of this document does not constitute authority for declassification of classified material of the same or similar content and title by the same authors. Printed in USA, Price 15 cents. Available from the Office of Technical Services, Department of Commerce, Wash- ington 25, D. C. -1- NOTES ON THE EFFECT OF MAGNESIUM ON PROCESSING By J. Weisman "Hiis memo reports the results of a number of experiments involving magnesium. Although only preliminary results have been obtained, it is felt that they should be placed on record. I - Effect of Marniesium on the Solubility of Uranium in bism uth The effect of magnesium on uranium solubility at 500°C vas investigated. Initial runs were made as follows: Approximately 10 grams of purified bismuth, 1 em of uranium plus the required amount of magnesium were placed above a coarse pyrex frit. The bismuth was melted under high vacuum, equilibrated at 50C°C, and then filtered by application of helium pressure. This procedure was not satisfactory because the magnesium reacted with glass. To prevent this, a graphite cup was inserted in the tube above the frit. To prevent bypassing of gas in filtration the glass was shrunk around the graphite. Holes which were small enough to retain the bismuth until gas pressure was applied, were drilled in the bottom of the cup. The molten metal was thus in contact with glass only for the few seconds required for filtration. TIsing the graohite sleeves the data shown in fig. 1 were obtained. It is seen that magnesium has a small but appreciable effect on uranium solubility. More data should be obtained, particularly at low magnesium concentrations. _?_ II - Reduction of tT ranium and Thorium Compounds by Magnesium The presence of large quantities of uranium oxide in Loop C, -iespite the addition of magnesium, indicates that at 500°C magnesium does not reduce HOj. Th02 also appears stable with resnect to magnesium. In one experiment Th and. TJ were oxidized into the salt phase by adding L10H to the salt. Thi3 salt was then contacted with bismuth containing 4900 ppm Mg. Although there were 930 ppm of U and 430 ppm of Th in the salt, no more than 10 ppm of T J and Th were detected in the metal. In contrast to this, the chlorides of U and Th are reduceable. The results of two runs are given below. With 54 ppm of Mg in the metal, only a slight reduction is obtained. However, with 450 ppm of Mg, good reduction is obtained, T^irthermore, the reduction of uranium proceeded to a far greater extent than that of thorium. In this run a separation factor of about 22 was obtained. It may be possible to base a blanket processing scheme on the selective reduction of uranium and thorium chlorides. TARLK I Results ?un No. Procedure ^ismuth °alt []^V 787 Th and TJ present in salt as oxides 4.0 ppm U 930 ppm TJ or hydroxides. Salt then contacted 10 ppm Th 4?0 ppm Th with bismuth containing magnesium. 4-900 ppm Mg /"Th and TJ added to salt as chloridea.\ 1,060 ppm Th 2,250 ppm Th Salt then contacted with Bi con- I 1,600 ppm U 157 ppm II taining Mg. / 450 ppm Mg 920 / ( 60 ppm r J 230 ppm TJ 4.7 ppm Th 280 ppm Th 54 ppm Mg III - The Reduction of ^are Earth Chlorides If the molten salt is thrown away after it is used for fission product extraction, its cost may be a considerable item. A cheap method of recovery and reuse of the salt would thus apoear desirable. -3- Previous experiments have shown that the rare earths may be extracted from the salt into molten bismuth by adding Mg to the metal. Since; in this case the bismuth acts only as an inert carrier, it should be possible to substitute lead for it. This will, of course, result in a considerable saving as the price of lead is less than 1/10 that of bismuth. Preliminary experiments have been carried out by J. Speirs using mixtures of lead and bismuth. Cerium was first transferred into the salt by contacting the salt with molten Bi containing Ce metal. The salt was then removed and contacted with a molten Pb - Bi alloy containing Mg. The results obtained are as follows: TABLE II PPM Ce in PPM Ce in Mg added to Run No. Metal 67.7 Salt metal initially 500 ppm ~\ 982 HI Mg analysis of 983 64.7 171 1000 ppm V metal after filtration and 984 62.7 H7 1000 ppm \ contact not available. Final value probably much less than that added. The results obtained indicate that cerium can be transferred to lead. They of course do not establish the capacity of the lead for fission products since the runs were carried out at low reductant concentrations. The capacity should be quite large since it is not necessary to retain the fission products in solution. If a large excess of reductant is used, the fission products should be extracted from the salt after their solubility in the metal is ex- ceeded. The limiting concentration would probably be set by heat removal considerations. Further experiments should be run using much larger excesses of the re- ducing agent. Both calcium and magnesium should be tried. IV - Tlse of Variable Oxidation Potential in Fuel Processing Scheme Several chemical processing loops are now being planned by the Fuel ,. Processing Group. In order to intelligently develop pumps, instrumentation and other components it is necessary to have some idea of the size of equipment which might eventually be used in an LMFR. A preliminary flow sheet has therefore been drawn up. The flow sheet proposed in fig. 2, has used as a design basis those parameters developed by 0. E. Dwyer in BML D-2S20. The flow sheet differs from that shown in D-2320 in that a closed salt cycle is used. It was also assumed that it was desirable to operate all columns continuously. This limits the minimum flow rate of any stream to abo'jt 2/20 of a gnu, (smallest flow in D-2320 was 1/5 gal/hr). "The use of larger flows necessitated the addition of another uranium stripping column in order to avoid excessive TT losses. -5- utn/u&jff .1 53 a *. $ **s \> 15 \l\ r > f < < V n H a 2 11 n 5 ■» S so ; I." = «-?i 1 J 3; ■i 1 E _ "J «9 a 3 st-i* •? g- I * £ <3 4 (J 3 e ■L, % C J J a < * < * 5 F n ^ i B ^ c