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The Use Op Cobalt-60 As a Radiotracer in a Study Op

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The Use Op Cobalt-60 As a Radiotracer in a Study Op THE USE OP COBALT-60 AS A RADIOTRACER IN A STUDY OP THE ANALYTICAL CHEMISTRY OF COBALT DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By DARNELL SALYER, B. S. The Ohio State University 1956 Approvec by: Adv^rer Department of Chemistry ACKNOWLEDGMENT The author would like to express his sincere appre­ ciation to Dr. T. R. Sweet for his guidance and advice during the period of this research. The author’s wife, Octavia Elizabeth Salyer, has been a source of help and encouragement during the con­ clusion of this work and the oreparation of the manuscript. Most of this work was completed while the author held graduate fellowships from the Cincinnati Chemical vVorks (1954-55) and the Central Division of the Allied Chemical and Dye Corporation (1955-56). The aid provided by these fellowsnips is gratefully acknowledged. ii Table of Contents Page INTRODUCTION ................................................ 1 THE ANODIC DEPOSITION PROBLEM........................... 9 Theory of Anodic Deposition ...................... 9 Conditions for the Deposition of C o b a l t ......... 13 Promising Methods, A Qualitative Study........... 16 Reproducibility, A Quantitative Study ........... 17 Nature of the Deposits................. ........... 27 Ignition of Deposits............................... 33 Summary of Optimum Conditions for Plating and Weighing...................................... 34 Preparation of the Standard Curve ................ 37 Interference Study.................................. 41 DETERMINATION OF SMALL AMOUNTS OF COBALT BY THE ISOTOPE DILUTION-ANODIC DEPOSITION' METHOD . 4 6 Separation of Cobalt from Iron............... 49 Conclusion................................... 49 A STUDY OF THE CATHODIC ElECTRODEPOSITION METHOD FOR oOBALT »»»»»••••»»»..»»•».»• 31 Previous W o r k ...................................... 53 Experimental. Examination for Residual Cobalt. 55 Measurement of the Rate of Deposition.......... 61 Explanation of Results.......... ................. 68 A Test for the Formation of Surface Compounds . 73 Determination of Residual Cobalt. » ............. 76 S u m m a r y ............................................. 79 ill Table of Contents (cont’d) Page THE PRECIPITATION OP COBALT AS COBALTINITRITE......... 81 The Reaction........................................ 82 Interfering Elements............................... 83 The Rate of Precipitation of Potassium Cooaltinitrite.................................... 84 Measurement of Rates............................... 86 Procedures........................................... 87 Results and Discussion............................. 89 Other Studies of Cobalt Precipitation ........... 100 Pot as slur Determinations........................... 109 S u m m a r y ............................................. 112 SOLUBILITY LOSSES DURING GRAVIMETRIC DETERMINATIONS. 116 The Potassium Cobaltlnitrite Separation ......... 116 The Double Ammonium phosohate Method............. 122 RADIOMETRIC TITRATIONS .................................. 129 Previous v.ork...................................... 129 Experimental........................................ 130 Discussion.......................................... 133 Results of the Study............................... 135 Conclusions........................................ 140 THE SOLUBILITIES OP COBALT ANTHRANILATES ............. 142 The Measurement of Solubilities .................. 143 Exoerinental........................................ 144 Results............................................. 152 iv Table of Contents (cont'd) Page SUMMARY................................................... 158 APPENDICES............................................... 160 BIBLIOGRAPHY ............................................. 189 AUTOBIOGRAPHY............................................. 197 v List of Tables Number Page 1 Comparison of Plating Methods ................... 13-19 2 Reproducibility Study I .......................... 21 3 The Use of Sand-Blasted Anodes............... 22 4 Reproducibility Study II...................... 24 5 Reproducible Deposits ............................ 26 6 Deposits from a Bicaroonate-HgCO^ Buffer. 28 7 A Titration Method for Per Cent Co In D e p o s i t s ................................. 32 8 A Check for the Codeposition of Sodium...... 36 9 Preparation of the Standard Curve ............... 39 10 Determinations After Separations. Interference Study.......................... 43 11 The Analysis of Kickel Alloys and Steels. 50 12 Conditions for the Electrodeoosition of Cobalt. 56 13 Results of Cobalt DeterminetIons by Several Methods........................... 59-60 14 Calibration of the Apparatus Used In the Rate Stud ies ........................ 65 15 Per Cent Cobalt Deposited vs. Tine of Electrolysis............................ 65 16 Residual Cooalt In Solutions from the Rote Studies................................. 66 17 Time Required for the Quantitative Deposition of Cobalt........................ 67 IS Cobalt Losses during the ./ashing of Deposits. 69 19 A Test for the Formation of Surface Compounds . 75 20 The Use of Spot Plate for Determining Cobalt in Electrolytes............................ 73 vi List of Tables (cont'd) Number Page 21 The Effect of Time on Cobalt Precipitation under Various Conditions. Volume Varied. 90 22 The Effect of Time on Cobalt Precipitation under Various Conditions. Temperature Varied................................... 92 23 The Effect of Time on Cobalt Precipitation under Various Conditions. The Amount of Cobalt Varied ................................ 97 24 The Effect of Time on Cobalt Precipitation under Various Conditions. The Amount of KNOg Varied ............................. 98 25 The Effect of Time on Cobalt Precipitation under Various Conditions. The Presence of Other Materials. ........... 101 26 Per Cent Cobalt Precipitated vs. Time. Kallmann’s Method. The Effect of Other Metals............................. 102 27 Per Cent Cobalt Precipitated vs. Time. Kallmann's Method. The Amount of Cobalt Varied ................................ 103 28 A Comparison of KNOg and KNOg + NaN02 as Reagents for Cobalt.................. 105 29 The Kffect of Organic Liquids on the Precipitation of Cobaltinitrite ...... 107 30 The Precipitation of Dipotassium Sodium Cobaltinitrite in Potassium Determinations. Ill 31 The "solubility" of Potassium Cooaltinitrite in water at 25° C ........................ 118 32 Losses of Potassium Cobaltinitrite on Washing with water and 10% Potassium Acetate ....................... 120 33 Solubility losses of Cobalt in Cobaltinitrite Determinations........................... 121 34 Solubility Losses of Cooalt in Determinations by the Double Phosphate Method......... 125 vii List of Tables (cont'd) Number Page 35 Losses of Cobalt Ammonium Phosphate on Washing with Different Solutions .... 128 36 Radiometric Titration Data........... 136-137 37 Preparation of the Cobalt Compounds of Anthranllic Acid and Several of its Derivatives .................................. 148-149 38 The Effect of Agitation Time on the Water Solubility of Cobalt Anthranilate at 25° C. 151 39 Standardization Data for the Active Cobalt Solution Used in the Solubility Studies • • 153 40 The Solubilities of the Cobalt Compounds of Anthranllic Acid and Several of its Derivatives .................................. 154-155 viii List of Figures Number Page 1 Drying Curve for Cobaltic Oxide.................... 25 2 Standard Curve for the Anodic Deposition-Isotope Dilution Method. • • • 40 3 Apparatus Used in the Electrodeposition Rate S t u d y ....................62 4 The Effect of Time on the Precipitation of Potassium Cobaltinitrite. Temperature Varied. 93 5 The Decomposition of KNOg with Time. ...............95 6 The Effect of Time on the Precipitation of Cobalt as Potassium Cobaltinitrite. The Presence of Organic Liquids..................... 108 7 The Effect of pH on Solubility Losses of C0NH4 PO4 ........................................ 126 8 Apparatus Used for the Radiometric Titrations. 132 9 Radiometric Titration of Cobalt with l-NItroso-2-Naphthol.............................138 10 Radiometric Titration of Cobalt with 1-Nitroso-2-Naphthol. The Effect of Nickel. 139 11 liquid Counter Apparatus ............................. 173 12 Response of the Liquid Counter ................ 177 ix INTRODUCTION The purpose of this investigation is to obtain infor­ mation concerning the analytical chemistry of cobalt which will be of value to the analyst and the analytical chemist. Radiotracer techniques are used in the study and in a broader 3ense the work will illustrate how radiotracer methods may be applied to analytical chemistry In general. The development of new methods for the analysis of cobalt, a critical examination of some of the standard methods, and a study of certain problems which have plagued previous Investigators are Included in the present work. 1 2 Cobalt - Its History, Occurrence, Abundance and Uses Although metallic cobalt was first prepared by Brandt In 1735 and the first significant chemical studies were made in 1802 by Thenard, the effects of cobalt, particularly its production of blue color In glasses and glazes, had been noticed and applied In early civilizations,1 Certain poisonous effects suffered by mine workers are responsible for the name of the metal, supposed to be from the German kobold, meaning goolin or gnome. In a monograph on cobalt, Young2 has described in detail
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