Collected Papers on Methods of Analysis for Uranium and Thorium GEOLOGICAL SURVEY BULLETIN 1006 This report concerns work done on behalf of the U. S. Atomic Energy Commission and is published with the permission of the Commission " ^. Collected Papers on Methods of Analysis for Uranium and Thorium Compiled by F. S. GRIMALDI, IRVING MAY, MARY H. FLETCHER, and JANE TITCOMB GEOLOGICAL SURVEY BULLET.IN 1006 This report concerns work done on behalf of the U. S. Atomic Energy Commission and is published with the permission of the Commission UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1954 3 UNITED STATES DEPARTMENT OF THE INTERIOR Douglas McKay, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. Price $1.00 (paper cover) FOREWORD The U. S. Geological Survey has made an extensive investigation of radioactive raw materials in the United States since 1945. This investigation was first undertaken on behalf of the Manhattan District Project and later on behalf of the U. S. Atomic Energy Commission. As a vital part of this program more than 200,000 samples have been chemically analyzed for uranium. These samples included nearly all types of minerals, rocks, and ores; mill, smelter, refinery, and other plant products; and natural waters. From the start of the program it was evident in the Geological Survey and elsewhere that the existing methods of uranium analysis were inadequate, and therefore much work has been done in modify­ ing known techniques and developing new ones. The first stage of this work was based on classical techniques; the second stage led to the development of more rapid methods to meet the constantly expanding analytical load. Work is continuing along both lines. What has been said about uranium analysis applies equally to thorium analysis. No satisfactorily rapid analytical methods for the chemical determination of thorium, especially for very small amounts (less than 1 percent), have been developed. The demand for thorium analyses is always pressing in the Survey program, and research in this field has been and is intense. The analytical methods developed from these investigations have been reported from time to time in U. S. Geological Survey Trace Elements Investigations and Memorandum reports, and many of these have been reproduced by the Technical Information Service of the Atomic Energy Commission at Oak Ridge, Term. These reports have had limited distribution in the Geological Survey and to the Atomic Energy Commission and its contractors, but it is desirable to make them available for wider distribution through formal publication. This bulletin will serve that purpose. The methods herein described include standard ones as well as those requiring the use of rather elaborate and highly specialized instru­ ments. The primary goal has been to develop methods that are of the widest applicability, and some procedures may be unnecessarily long when applied to simple materials. The papers are presented in nearly chronologic order and thus reflect the changing demands on the laboratory. The reports have been kept essentially in their original form except where it has been necessary to bring the material up to date. Some of the earlier methods have, been superseded by those described in later reports; in IV FOREWORD nevertheless, they are presented here because the information they contain is valuable and useful. The authors who compiled this bulletin have prepared a general discussion (part 1) of uranium and thorium analysis that will be most useful to those working in this field. JOHN C. RABBITT, Chief, Trace Elements Section. CONTENTS Page PART 1. Summary of methods of analysis for the determination of uranium and thorium, by F. S. Grimaldi, Irving May, M. H. Fletcher, and Jane Titcomb._____________________________ 1 2. Methods for the complete decomposition of rock and ore samples to be analyzed for very small amounts of uranium and thorium, by M. D. Foster, R. E. Stevens, F. S. Grimaldi, W. G. Schlecht, and Michael Fleischer___________________________________ 11 3. The Geological Survey cupferron precipitation-extraction method for the determination of very small amounts of uranium in naturally occurring materials, by F. S. Grimaldi-___________ 17 4. The Geological Survey carbonate-phosphate-peroxide method for the determination of very small amounts of uranium in natu­ rally occurring materials, by M. D. Foster and R. E. Stevens.. 29 5. Elimination of interference by nickel in the determination of uranium by means of zinc amalgam reductors, by F. S. Gri- maldi_______________________.--------._---._-_-___ 37 6. The visual fluorimetric determination of uranium in low-grade ores, by F. S. Grimaldi and Harry Levine____-_---________- 43 7. A volumetric filtering pipette, by F. S. Grimaldi-_____________ 49 8. A study of critical factors in the "direct" fluorimetric determi­ nation of uranium by Mary H. Fletcher___________________ 51 9. A direct fluorimetric method for the determination of small amounts of uranium in the field and laboratory, by F. S. Grimaldi, F. N. Ward, and Ruth Kreher Fuyat. _ _____ 69 10. An improved fluorimeter for the determination of uranium in fluoride melts, by Mary H. Fletcher and Irving May__-____- 77 11. A transmission fluorimeter for use in the fluorimetric method of analysis for uranium, by Mary H. Fletcher, Irving May, and Morris Slavin___---____---__---__-_----__----___-_-____ 85 12. The design of the Model V transmission fluorimeter by Mary H. Fletcher, Irving May, and J. W. Anderson_________________ 93 13. A battery-powered fluorimeter for the determination of uranium, by Irving May and Mary H. Fletcher____________,_________ 97 14. Short routine direct method for the fluorimetric determination of uranium in phosphate rocks, by F. S. Grimaldi and Norma S. Guttag._________-_-____--_--_------_-._------_-_- _. 105 15. Fluorimetric determination of uranium in shales, lignites, and rnonazites after alkali carbonate separation, by Norma S. Guttag and F. S. Grimaldi--________-__________ 111 16. Noninterference of arsenate ion in the volumetric determination of uranium using the Jones reductor, by Jack J. Rowe______ 121 17. The fluorimetric determination of uranium in nonsaline and saline waters, by Audrey Pietsch Smith and F. S. Grimaldi-_ 125 18. The Geological Survey phosphate-fluoride-iodate method for the determination of very small amounts of thorium in naturally occurring materials, by F. S. Grimaldi and J. G. Fairchild___ 133 V VI CONTENTS Page PART 19. The Geological Survey carbonate-iodate-iodine method for the determination of small amounts of thorium in naturally occur­ ring materials, by J. J. Fahey and M. D. Foster.___________ 153 20. The determination of thorium in high-grade and low-grade ores, by F. S. Grimaldi and Charlotte Marsh Warshaw___________ 169 21. Mesityl oxide extraction method for thorium analysis, by Harry Levine and F. S. Grimaldi _ _____________________________ 177 ILLUSTRATIONS [Plates 3-8 in pocket] Page PLATE 1. Assembly of Model II transmission fluorimeter______________ 62 2. Model II transmission fluorimeter__-______________-_______ 63 3. Rear-view assembly and expanded details of the modified fluorimeter. 4. Fluorimeter assembly. 5. Cutaway view, cross section, and details of parts of "fluorimeter". 6. Details of parts of fluorimeter assembly shown in plate 4. 7. Details for construction of shield. 8. Details for construction of type-B phototube housing. FIGURE 1. Volumetric filtering pipette._______________-______------__ 50 2. Details of volumetric filtering pipette______________________ 50 3. Effect of fusion conditions on fluorescence of blank samples. _ _ 57 4. Effect of fusion conditions on fluorescence of standard samples. 57 5. Effect of fusion conditions on sensitivity..---.______________ 58 6. Equipment--_-_____-___________--______--___-_-__-____- 62 7. Effect of fusion conditions on fluorescence of standard samples as shown in new data__________________________________ 66 8. Effect of fusion time and type of platinumware on fluorescence of standard samples.-.-----------.--------------------- 68 9. Complete assembly of the modified fluorimeter______________ 79 10. Standardization curves for 3.0-g discs prepared by fusion in 30-mlcrucibles_______________________-_____________.__ 80 11. Standardization curves for 1.5-g discs prepared by fusion in crucible lids.____-_______--_------------------------- 81 12. Calibration curves for routine work.__._____-______-.___.__ 83 13. Schematic diagram of a "reflection"-type fluorimeter_________ 86 14. Schematic diagram Of a transmission-type fluorimeter________ 87 15. Lamp circuit used in the instrument-______________________ yy 16. Reflecting support for the lam.p_______________ ____________ 101 17. Power circuit for the photomultiplier tube_.________________ 101 18. Standard CUrV6..______. ._ . - 102 19. Platinum dish used for fusions.-..----------.-------------- 103 20. Working curve_-_.__________________--------_---_-__ 109 21. Spectral transmittancy curve for the determination of thorium with p-dimethylaminoazophenylarsonic acid________._...-- 150 CONTENTS VII FIGURE 22. Fisher electrophotometer readings for the photometric de­ termination of thorium with p-dimethylaminoazophenylar- sonic acid___-_________-_-_-_______--_--_-----__--_-__ 151 23. Spectral transmittancy curve of iodine in carbon tetrachloride. 164 24. Transmittance-concentration curves of iodine in carbon tetra­ chloride -___-__________------__-___--_--_____---______