Separation of Hafnium and Zirconium by Liquid-Liquid Extraction" (1953)
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Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations 1953 Separation of hafnium and zirconium by liquid- liquid extraction Howard Carl Peterson Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Chemical Engineering Commons Recommended Citation Peterson, Howard Carl, "Separation of hafnium and zirconium by liquid-liquid extraction" (1953). Retrospective Theses and Dissertations. 15123. https://lib.dr.iastate.edu/rtd/15123 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. 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ProQuest Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0000 NOTE TO USERS This reproduction is the best copy available. UMI* SEPARATION OF HAFNIUM AND ZIRC0NIUI4 BY LIQUID-LIQUID EXTRACTION W Howard Carl Peterson A Dissertation Submitted to the Graduate Faculty in Partial Fulfillment of The Requirements for the Degree of DOCTOR OF PHILOSOPHY Major Subject: Chemical Engineering Approved: Signature was redacted for privacy. In'Charge dbf Major Work Signature was redacted for privacy. Head of Major Depaittaent Signature was redacted for privacy. Dean! of Graduate College Iowa State College 1953 UMl Number; DP12908 UMI © UMI Microform DP12908 Copyright 2005 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 -ii- TABLE OF CONTENTS Page NOTATION AND DEFINITION OF TERMS V SUmRY 1 INTRODUCTION 3 INVESTIGATION 8 Preparation of Zirconium Nitrate Feed Solution 8 Leaching of fusion mass 9 Dissolution of fusion mass in hydrochloric acid . * . 11 Dissolution of fusion mass in sulfuric acid ..... 13 Dissolution of fusion mass in nitric acid ...... 1$ Fractional Liquid-liquid Extraction 18 Investigation of Extraction Variables ....• 26 Settling time .......... 26 Solvent degradation ..... 27 T^ass transfer and separation 31 Distribution of hafnium and airconiiun Itl Extraction from a cliloride-nitrate solution ..... 1^9 Extraction from sulfate-nitrate solution . $0 Continuous Extraction Runs . .... 52 Continuous run A 58 Continuous run B * 6k DISCUSSION 73 CONCLUSIONS ............ 8U LITERATUr® CITED 8? ACKNOWLEDGIffiNTS 8? APPENDICES 90 -iia- Page Appendix At Analytical Methods 91 Oxide concentration 91 Total acidity 92 Nitric acid concentration 92 Hafnium-zirconim ratio * 92 Sulfate analysis 92 Chloride analysis 93 Silicon analysis 93 Sodium analysis of fusion mass 9U Minor elements 9h Appendix B: Sample Calculation ..... .. 95 Data from experimental work 9$ Aqueous phase calculations ... ... 95 Organic phase calculations 96 Calculation of distribution coefficients 97 Calculation of separation factor . 97 -iil- LIST OF TABLES Page Table 1 Evaluation of Leaching Fusion Mass with Cold Distilled V«'ater 10 Table 2 Analyses of Typical Leached Fusion Masses 11 Table 3 Effectiveness of Water VJashing the Ciiloride Ion from Zirconium t^droxide 12 Table U Effectiveness of V/ater Waslu.ng the Sulfate Ion from Zirconium hydroxide II4. Table $ Silicon Removal by Evaporation to Dryness of Fusion Mass and Nitr!.c Acid I6 Table 6 Physical Characteristics of Tributyl Phosphate Solvent Mixtiires 2Q Table 7 Results of Six-stage Simulated Column Runs ..... 35 Table 8 Mass Transfer and Separation in Six-stage Simulated Column Runs, Variation of Nitric Acid ... 39 Table 9 Mass Transfer and Separation in Six-stage Simulated Column Runs, Variation of Per Gent Tributyl Phosphate ...... ..... UO Table 10 Equilibrim Contacts rath Varying Hafnium-zirconiton Ratios in the Feed Solutions I|2 Table 11 Effect of Ciiloride Ion on Mass Transfer and Separation $0 Table 12 Effect of Sulfate on Mass Transfer and Separation . 53 Table 13 Results of Simulated Column Run I 59 Table lii Analyses of Minor Elements in Ox3.des, Rxin A 66 Table 15 Stagewise Analyses of Run A 67 Table I6 Results of Simulated Column Run II 68 Table 17 Analyses of Minor Elements in Oxides, Run B . 71 Table 18 Stagewise Analyses of Run B 72 Table 19 Preliminary Chemicals Cost Analysis 82 -iv- LIST OF FIGURES Page Figure 1 Schematic Flow Diagram o£ Ames Laboratory Process $ Figure 2 Schematic Diagram of Extraction Column . 20 Figure 3 Location of Operating Lines 21 Figure 1; Transition between Operating Lines at Feed Point . 21 Figure 5 Hyi^othetical Equilibrium Diagrams 23 Figure 6 Flow Pattern for Six-stage Simulated Column Run ... 32 Figure 7 Effect of Nitric Acid on Oxide Distribution 37 Figure 8 Effect of Diluent on Oxide Distribution 30 Figure 9 Effect of Hafnium on Distribution of Hafnium-zirconium Oxide 1^3 Figure 10 Effect of Hafnium on the Distribution of Zirconium . iUt Figure 11 Effect of iiirconium on the Distribution of Hafnium . Figure 12 Effect of Hafnium on Zirconium Distribution Coefficient F3.gure 13 Effect of Zirconium on Hafnium Distribution Goefficxexit ..................... i4-7 Figure lU Effect of Hafnium on the Separation Factor 1+8 Figure 15 Effect of Chloride Ion on Mass Transfer of Hafnium-zirconium Oxide 51 Figure 16 Effect of Sulfate Ion on Mass Transfer of Hafnium-zirconium Oxide 5k Figure 17 Arrangement of Stages in Countercurrent Extraction Operation ......... 56 Figure 18 Oxide Equilibrium Line from Simulated Column Run I . 60 Figure 19 Modified McCabe-Thiele Diagram for Run A 62 Figure 20 Schematic Flow Sheet of Rim A 65 Figure 21 Oxide Equilibriiam Line from Simulated Column Run II 69 NOTATION ANT) DEFINITION OF TERMS Aqueous product. The aqueous stream leaving the stripping unit, containing liafniura-free zirconium. Column. Any piece of equipment vjhich contacts two liquids in a counter- curr-ent fashion. Distribution coefficient. The ratio of the concentration of a component in the organic phase to its concentration in the aqueous phase. Extract, The organic stream leaving the extraction apparatus, contain ing hafnium-free zirconium. Extraction apparatus. The equipment consisting of both the extraction and scrub sections. l;)xtraction section of the colvunn. The stages in wliich the aqueous volume consists of the scrub and feed volmes. The organic solvent enters tlie extraction section and the raffinate stream leaves the extraction section. Feed. An aqueous solution of hafnium and zirconium nitrates, normally in the ratio Hf x lOO/Zr 2.2-2.5. Fusion Mass. Reaction product of zircon sand and caustic soda. Krr^.* Distribution coefficient of hafnium, ofg* Hf gm. Hf/1. aq. Kr, , Distribution coefficient of zirconium, gm. Zr/l. aq. Nitric acid concentration. The result of the following analyses of the solution: total acidity - 2(molarity of hafnium and zirconivm). Oxide concentration. Concentration of hafnium-zirconium oxides, weight per unit volume. Q. Volume rate of flow, volume per unit time, Raffinate. The aqueous stream leaving the extraction section, contain ing a high ratio of hafnium to zirconium. Scrub, An aqueous solution of nitric acid introduced to the extraction apparatus to remove the small amount of hafnium in the organic solvent. -Ti- Scrub section of the column. The stages in which the aqueous volume consists of the scrub volume and in which the organic phase contains oxide mth low hafnium-zirconium ratios. The extract leaves the scrub section. Separation factor. An index of purification, equal to (Ht X 100/Zr)jq. Stage. The contacting and separating of the organic and aqueous phases in such a manner that the two exit streams are in eqviili- brium. Stripping unit. An extraction apparatus used to remove the hafnium- free zirconium frora the extract phase with distilled water, TBP, Tributyl phosphate. Total acidity. The total amount of standard base required to neutralize the free acid and to precipitate the hafnium and zirconium in solution. A phenolphthalein indicator was used, X, Concentration in the aqueous phase, y. Concentration in the organic phase, 3, Separation factor. SubscriptsJ A» Aqueous phase E, Esrtract F, Feed R, Raffinate S, Scrub T, Organic solvent -1- SU1«4ARI A liquid-liquid extraction process has been developed which produced an aqueous solution of airconium nitrate containing less than 100 parts of hafnium per million parts of zirconium. An