THE BINARY AND TERNARY SYSTEMS FORMED BY CALCIUM FLUORIDE, LITHIUM FLUORIDE AND BERYLLIUM FLUORIDE; PHASE DIAGRAMS AND ELECTROLYTIC STUDIES By John L. Speirs A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry 1952 ProQuest Number: 10008473 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10008473 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 ACKNOWLEDGMENT The writer wishes to express his sincere appreciation of the patient guidance of Dr. Laurence L. Quill in all phases of the investigation. Thanks are also due to Dr. Elmer Leininger for his helpful advice on analytical pro­ cedures . **• -X - 345842 THE BINARY AND TERNARY SYSTEMS FORMED BY CALCIUM FLUORIDE, LITHIUM FLUORIDE AND BERYLLIUM FLUORIDE: PHASE DIAGRAMS AND ELECTROLYTIC STUDIES By John L. Speirs AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Chemistry Year 19^2 Approved John L. Speirs THESIS ABSTRACT Production of elemental fluorine from calcium fluoride by a direct method involving electrolysis of fused fluoride mixtures was considered. A ternary mixture was required to obtain the lowering in the melting point of calcium fluoride essential to give the possibility of fluorine recovery after electrolytic evolution. Lithium and beryllium fluorides were chosen from among the limited number of possible additives for the purpose. The binary system phase diagrams were determined for the component systems* calcium fluoride— lithium fluoride, calcium fluoride—beryllium fluoride and lithium fluoride—beryllium fluoride. For the latter system the results were compared with the conflicting reports of two earlier investigations. Methods of synthesis of two compounds occurring in these systems were discussed and X-ray examinations reported for calcium fluoberyllate, CaB.eF4, and lithium fluoberyllate, LigBeF^ The phase diagram of the ternary system calcium fluoride—lithium fluoride—beryllium fluoride was determined. A region of suitably low temperature was located in which, however, the calcium fluoride content was very small. Electrolyses of mixtures in this composition region of the ternary system produced inconclusive results. Evolved fluorine reacted with the anode preventing any recovery of gaseous product. It was not possible to demonstrate the cathodic deposition of calcium and thus determine whether, effectively, calcium fluoride was being decomposed rather than one of the additive substances. TABLE OF CONTENTS PAGE INTRODUCTION.......................................................................................................................... 1 GENERAL AND THEORETICAL........................................................................................ 5 Sources of Fluorine and Methods of Production .............................. 5 Theoretical and Practical Problems of Fused Salt Electrolysis 8 Relative Decomposition Potentials and Choice of Components.. 16 Effect of Liquid Metal Cathodes on Potential ................................ 27 Available Information on Phase Relations and Anticipated B ehaviour .................................................................................................. 31 The Phase Rule ............................................................................................ 33 EXPERIMENTAL............................................................................................................... bZ Preparation of M aterials ...................................................................... h2 Equipment ..................................................................................................... $1 General Procedure ..................................................................................... 56 THE SYSTEM CALCIUM FLUORHJE-LITHIUM FLUORIDE....................................... 67 Phase Diagrams ............................................................................. .................69,70 THE SYSTEM CALCIUM FLUORIDE-BERYLLIUM FLUORIDE.................................. 7h Phase Diagram .................................................................... 78 THE SYSTEM LITHIUM FLUORIDE-BERYLLIUM FLUORIDE................................. 86 Phase Diagrams (re suits of this work) ......................................... 91,93,9k Comparison with Previously Reported Results .............................. 97 Phase Diagrams (results of earlier workers) ...........................101,103 THE TERNARY SYSTEM CALCIUM FLUORIDE-LITHIUM FLUORIDE-BERYLLIUM FLUORIDE..........................................................................................................109 P a rt A — G eneral .................................................................. 109 Part B — The LiF-Rich Portion of the Ternary System ........... 116 Phase Diagram (partial) ....................................................117 Part C — The BeF2-Rich Portion of the Ternary System ......... 121 Phase Diagram (partial) ....................................................122 Part D — The LigBeF^Rich Portion of the Ternary System.... 127 Phase Diagram (partial) ....................................................130 TABLE OF CONTENTS - Continued PAGE Part E — The System CaF2-LiF-BeF2 as a Whole ....................................Ik8 Phase Diagram .................................................................................. Ik9 ELECTROLYTIC INVESTIGATIONS IN THE TERNARY SYSTEM......................................153 SUMMARY AND CONCLUSIONS.............................................................................................165 APPENDICES........................................................................................................................ 166 1. Summarized References on Phase Relations of Calcium Fluoride, Lithium Fluoride, Beryllium Fluoride and Analogous Compounds ............................................. ................ 166 2. Physical and Thermal Properties of Calcium Fluoride, Lithium Fluoride and Beryllium Fluoride ..........................................170 3. Summarized Information on Fluoberyllates and Analogous Compounds ...................................... 176 k. Information on Alloy Systems .................................................................178 5. General Phase Relations in Ternary Systems ...................................180 6. Sample Numbering Systems .......................... ............................................ 201 7. Results of Thermal Analyses of CaF2-LiF System .......................... 203 8. Results of Thermal Analyses of CaF2-BeF2 System ........................205 9. Results of Thermal Analyses of LIF-BeF2 System .......................... 209 10. Calcium Fluoberyllate; Results of Wet and Dry Syntheses, Optical and X-ray Data ..................................................... 217 11. Lithium Fluoberyllate; Results of Syntheses of Mono- lydrated and Anhydrous Compounds, X-ray Data ...............................227 12. Results of Thermal Analyses of CaF2-LiF-BeF2 System ...................23k 13. Qualitative X-ray Data for Ternary System Samples ......................2k9 lk. Analytical Methods .......................................................................................257 15. Analytical Results ..................................................................................... 266 Part A — Analysis of Calcium Fluoride ................................. 266 TABLE OF CONTENTS - Continued PAGE Part B — Analysis of Beryllium Fluoride and "Beryllium Carbonate" ................................................268 Part C — Analysis of Ammonium Fluoberyllate Preparations ................................................................... 270 Part D — Analysis of Beryllium Basic Acetate Preparations ................................................................... 271 Part E — Analysis of LiaBeF4.lH20 Preparation and Determination of Solubility of Li2BeF4 273 Part F — Discussion of Analytical Accuracy and Correction of Calculated Compositions 277 Part G — System CaF2-LiF Analyses .......................................... 279 Part H — System CaF2-BeF2 Analyses ........................................ 282 Part I — System LiF-BeF2 Analyses .......................................... 287 Part J — System CaF2-LiF-BeF2 Analyses ................................297 Part K — Analysis of Electrolytic Samples ....................301 16. Conductance Measurements ................. 30lt LITERATURE CITED.........................................................................................................307 v i LIST OF FIGURES FIGURE PAGE 1 ............................................................................................................................ 69 2 ...........................................................................................................................