THE HYDROXYL FELSPATHOIDS PHASE RELATIONS OF THE HYDROXYL FELSPATHOIDS IN THE SYSTE14 NaAlSiO4-NaOH-H 0 2 By PETER ASCROFT MACKENZIE ANDERSON, B.Se., M.Se. A Thesis Submitted to the Faculty of Graduate Studies in Partial Fulfilment of the Requirements for the Degree Doetor of Philosophy McMaster University May 1968 DOCTOR OF PHILOSOPHY (1968) McMASTER UNIVERSITY (Geology) Hamilton, Ontario TITLE: Phase Relations of the Hydroxyl Felspathoids in the System NaAlSi0 -NaOH-H 0 4 2 AUTHOR: Peter A.M. Anderson, B.Sc. (London University) M.Sc. (McMaster University) SUPERVISOR: Dr. B.J. Burley NUMBER OF PAGES: ix, 78 SCOPE AND CONTENTS: A stUdy was made of the phase relationships in the system NaAlSi0 -NaOH-H 0, at 15,000 p.s.i. and at 450°C, 520°C, 4 2 600°C and 700°C. The following phases were found and characterised: hydroxyl varieties of nosean, sodalite and cancrinite, with formulae approximating to 3NaA1Si04.NaOH.xH20, l6:.xbl.5, sodic nepheline and phase X, apparently a previously unreported phase, with composition approaching Na Al Si 0 • Approximate phase diagrams were deduced 4 2 2 9 for the four temperatures. i1 ACKNOWLEOOEMENTS The writer is very deeply indebted to Dr. B.J. Burley, without whose continued guidance and support, this investigation would have been quite impossible. Drs. C. Calvo and H.P. Schwarcz have also been generous with time and advice, throughout the project. The assist- ance of others, too numerous to mention individually, has been readily given and gratefully accepted; these include most of the members of the Department of Geology. The care and resourcefulness of Mr. J. Muysson, in effecting the chemical analyses under difficult conditions, is greatly appreciated. The essential financial support included research funds from the National. Research Council of Canada, bursaries from the Bickell Foundation, and an Ontario Graduate Fellowship. iii TABLE OF CONTENTS Page CHAPTER I. Introduction, and synopsis of the thesis ••••••••••••• 1 CHAPTER II. Relevant previous information, and design of this investigation ••••••••••••••••••••••••••••••••••••••• 4 A. The felspathoids •••••••••••••••••••••••••••••••••••••••• 4 Nepheline family •••••••••••••••••••••••••••••••••••••••• 5 .' Nosean and 50dalite ••••••••••••••••••••••••••••••••••••• 6 Cancrinite •••••••••••••••••••••••••••••••••••••••••••••• 8 B. The system NaAlSi0 -NaOH-H 0, and its Parts ••••••••••••• 10 4 2 NaOH-H 0 ••••••••••••••••••••••••••••• ~ •••••••••••••••••• 10 2 NaA1Si0 -H 0 •••••••••••••••••••••••••••••••••••••••••••• 11 4 2 NaA1Si04-NaOH ••••••••••••••••••••••••••••••••••••••••••• 11 NaAISi0 -NaOH-H 0 ••••••••••••••••••••••••••••••••••••••• 11 4 2 C. The design of this investigation •••••••••••••••••••••••• 13 The "natural" fe1spathoid system •••••••••••••••••••••••• 14 The minimal felspathoid system •••••••••••••••••••••••••• 14 Specific problems for study............................. 14 Choice of values for experimental parameters, and experimental method •••••••••••••••••••••••••••••••••••• 15 CHAPTER III. Experimental method ••••••••••••••••••••••••••••••••• 17 Hydrothermal synthesis ••••••••••••••••••••••••••••••••••••• 17 Examination of reaction products ••••••••••••••••••••••••••• 18 Optical and x-ray procedures ••••••••••••••••••••••••••••••• 18 Analytical procedures •••••••••••••••••••••••••••••••••••••• 19 Calculation of charge compositions ••••••••••••••••••••••••• 19 iv TABLE OF CONTENTS (continued) Page The use of palladium black in charges ••••••••••••••••••••••• 20 CHAPTER IV. The properties of the phases .......................... 21 Nepheline ••••••••••••••••••••••••••••••••••••••••••••••••••• 21 Hydroxyl nosean ••••••••••••••••••••••••••••••••••••••••••••• 25 Hydroxyl sodalite ••••••••••••••••••••••••••••••••••••••••••• 26 The nomenclature of hydroxyl nosean and hydroxyl sodalite ••• 28 Hydroxyl cancrinite ••••••••••••••••••••••••••••••••••••••••• 29 Phase X ••••••••••••••••••••••••••••••••••••••••••••••••••••• 30 Fluid phase ••••••••••••••••••••••••••••••••••••••••••••••••• 31 CHAPTER V. The general phase relationships •••••••••••••••••••••••• 32 Experimental results in the isothermal sections ••••••••••••• 32 General relationships in the isothermal sections •••••••••••• 32 Quench phases ••••••••••••••••••••••••••••••••••••••••••0.... 33 The inclusion of phases ••••••••••••••••••••••••••••••••••••• 34 Kinetic effect experiments •••••••••••••••••••••••••••••••••• 34 The anomalous occurrence of sodalite •••••••••••••••••••••••• 35 The widespread occurrence of nepheline, at higher temperatures 36 The fluid phase analyses •••••••••••••••••••••••••••••••••••• 38 The pseudo-ternary nature of the plane •••••••••••••••••••••• 41 Specific relationships at the four temperatures ••••••••••••• 42 CHAPTER VI. Discussion •••••••••••••••••••••••••••••••••••••••••••• 43 Equilibrium in the experimental results ••••••••••••••••••••• 43 The relationship of hydroxyl nosean and hydroxyl cancrinite. 45 The relationship of hydroxyl nosean and hydroxyl sodalite... 47 v TABLE OF CONTENTS (continued) Page The application of these results ••••••••••••••••••••••••••• 48 Summary •••••••••••••••••••••••••••••••••••••••••••••••••••• 49 REFERENCES CITED ••••••••••••••••••••••••••••••••••••••••••••••••• 51 APPENDIX I. Section 1. Experimental method ••••••••••••••••••••••••••••• 56 A. The reactant gels •••••••••••••••••••••••••••••••••••• 56 B. Execution of the reactions ••••••••••••••••••••••••••• 57 C. Treatment of the reaction products ••••••••••••••••••• 59 D. Optical examination of the reaction products ••••••••• 60 E. X-ray examination of the reaction products ••••••••••• 60 F. Analytical p~ocedures •••••••••••••••••••••••••••••••• 62 Section 2. Detailed experimental results ••••••••••••••••••• 65 General ••••••••••••••••••••••••••••••••••••••••••••••••• 65 The compositions and reaction products of the charges ••• 65 The results of the fluid phase analyses ••••••••••••••••• 66 APPENDIX II. Comprises the x-ray diffraction patterns, crystals and other products of experimentation, and is under separate cover. vii LIST OF TABLES Page TABLE 1. Summary of the properties of the crystalline phases •••• 23 2. Comparison between nepheline from charges very rich in NaOH, and those of lower NaOH content ••••••••••••••• 24 App.-l. Analyses of the Reagent Gels •••••••••••••••••••••••••••• 67 App.-2. Analyses of the Synthetic Crystalline Phases •••••••••••• 68 App.-3. X-ray Reflections of the Crystalline Phases ••••••••••••• 69 App.-4. Compositions and Reaction Products of the charges ••••••• 74 App.-5. Results of the Fluid Phase Analyses ••••••••••••••••••••.• 78 viii LIST OF FIGURES Page TIGURE A. The Sodic End of the System NaA1.Si0 -KAlSi0 ............. 4 4 6a 6a C. The Join NaAlSi04-NaOH ••••••••••••••••••••••••••••••••••• l3a D. Photographs of the Phases •••••••••••••••••••••••••••••••• 2la E. Compositions of the Analyses Phases •••••••••••••••••••••• 2ld F. Cell Parameters of Hydroxyl Nosean and Hydroxyl Sodalite.. 26a G. The Experimental Results at 450°0......................... 32a H. The Experimental Results at 520°0......................... 32b I. The Experimental Results at 600°0......................... 32c J. The Experimental Results at 700°0......................... 32d K. The Fluid Phase Analyses • •••••••••••••••••••••••••••••••• 38a L. The Inferred Relationships at 450°0....................... 42a M. The Inferred Relationships at 520°C....................... 42a N. The Inferred Relationships at 600°0....................... 42b o. The Inferred Relationships at 700°0....................... 42b ix CHAPTER I INTRODUCTION, AND SYNOPSIS OF THE THESIS This is the record of an experimental study, concerning those hydroxyl analogues of the felspathoidal minerals, which form in the sys~em NaAlSi0 -NaOH-H 0. The intention was to delineate the pro­ 4 2 perties and stability relationships of these SUbstances, at 15,000 p.s.i. total pressure, and at temperatures from 450°C to 600°c. The chemical compositions of this system range far from those likely to be found in nature, and the connection with natural rocks and minerals is, at first sight, tenuous. Investigation of this system is, however, a logical early step in the experimental study of the fels­ pathoids, the natural forms of which require at least eleven ohemical components for description of their compositions. The system Na20-A1203-Si02-H20 is an obvious starting point for the felspathoids, because it would appear to be the only system of four components in which representatives of all distinct groups of this type of mineral are found. In fact, the compositions of these hydroxyl felspathoids lie on, or near to, the plane NaA1Si0 -NaOH-H 0. Know­ 4 2 ledge of the phase relationships on this plane should be an excellent foundation for extension into more complex systems. 1 2 About two hundred charges, with chemical compositions lying at various points on or near the composition plane NaAlSi0 -NaOH-H 0, 4 2 were held at fixed temperature and pressure for two to three weeks. The crystalline contents of the charges were then examined optically. by x-ray diffraction and by chemical analysis. and the relationships of the crystalline types were studied. The range of the investigation was somewhat extended. to include the temperature of 700°C. and some excess Na 0 in the range of compositions. 2 Five crystalline phases were encountered and characterised. Nepheline. hydroxyl-nosean. hydroxyl-cancrinite and hydroxyl-sodalite were present, as had been expected. A further substance, with compo­ sition approximating