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accuracy. The results showed that the Iep ES measurements were within 2.4 % ofthe expected phosphorus concentrations, and 7 % ofthe expected sodium concentrations. Each original sample was diluted to give two aliquots within the range 50-200 ppm in Na and P, and agreement was within ±3 %. The results that were received from ICP-ES analysis were the elemental concentrations (ppm) ofthe diluted samples. Using a Microsoft Excel spreadsheet and the mass dilution factors ofeach diluted sample, the sodium and phosphorus molality concentrations ofeach original sample taken from the stirred reactor were calculated. 2.3.4 Electron Microscopy From the synthesis experiments, the solid reaction products ofspecific interest to this study were analyzed by scanning electron microscopy (SEM) at an accelerating voltage of20 kV in a Hitachi S570 SEM equipped with a Tracor Northern 5500 cnergy dispersive X-ray analyzer and a Microtrace Model 70152 silicon X-ray spectrometer, located in the Department of BiologylMUN. Detector/sample positioning gave an effective takeoffangle of30" and SEM images were recorded on Polariod Type 655 PositiveJNegative film. Samples were placed on double sided sticky tabs on aluminium stubs and carbon coated in a Denton 502A High Vacuum Evaporator before SEM analysis.
2.4 Synthesis and Characterization of Hideout Reaction Products 2.4.1 Experimental Design In the sodium-iron-phosphate study conducted previously in our laboratory (Quinlan, 1996; Bridson et aI., 1998), the Parr 4744 reaction vessel was modified in order to isolate SIHP from the reaction mixture because other workers have reported (Taylor et a!., 1979; Broadbent et aI., 1978; Tremaineet at, 1993) that it is unstable at temperatures lower than 180°C in the presence ofwater. The experimental design ofthe reaction vessel thus prevented the reaction product from coming in contact with liquid water during the isolation step and also prevented dehydration ofthe equilibrium phase. The same experimental design was applied to allihe experiments conducted throughout this study. The experimental procedure is as follows. The sodium-phosphate or ammonium phosphate solution was initially placed in the Teflon liner. Because ofthe thennal expansion effect, the vessels were not overloaded with solution in order to prevent a pressure build up. The solid starting materials were added once the Teflon filter cup was positioned above the level ofthe solution and a Teflon lid was put into place. The Teflon assembly was then placed inside the stainless steel pressure vessel to which a corrosion disc and a rupture disc were added, followed by a stainless steel pressure vessel lid. The lid was hand tightened and tightened a further 1/8 revolution by a specially designed pressure vessel wrench. The vessel was thcn placcd in a high temperature oven at either 200"C or 250"C and inverted. As seen in Figure 2.2, the solution passes through the filter and is allowed to react with the solid starting materials once invened. The vessels
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1"'1 National Library of Canada Bib
Page 8:
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Page 11 and 12:
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Page 15: LIST OF TABLES Table 1.1 Corrosion
Page 21 and 22: single crystals ofquartz (Nacken, 1
Page 23 and 24: phosphate control in the 19&Os was
Page 25: the standard Gibbs energies and ent
Page 36: consist ofortnophospllatcs. The bou
Page 41 and 42: 2 FcIlFc[[J204(S) + 26 Na+(aq) + 12
Page 44 and 45: solubility and phase relations ofpr
Page 46: where 11 equals the ionic state ofh
Page 49: '", g :£ 30
Page 55: 1.10 Project Objectives The objecti
Page 61 and 62: II - "7 /'7"7L 41 J n
Page 65: 2.3.2 Single Crystal X-Ray Dif'frac
Page 69 and 70: Several solid starting materials we
Page 75 and 76: FeUlNTA(aq) + HPOl(aq) + NH/(aq) __
Page 77 and 78: All runs lasted up to to days at a
Page 79 and 80: 0.0 l--l_-L_l-....J.._-L_l-....J..-
Page 81 and 82: dissolution orSNHP and allowed the
Page 83 and 84: (a) (b) Figure 3.1a and b: Scanning
Page 87 and 88: and the equilibrium constant for ma
Page 89 and 90: groups. Oxidizing agents were previ
Page 91 and 92: and reacted with aqueous sodium pho
Page 94 and 95: (al (b) Figure 3.5a and b: Scanning
Page 97 and 98: Figure 3.7: Scanning electron micro
Page 99: Table 3.1: Positional parameters fo
Page 104: Figure 3.10: Scanning electron micr
Page 107 and 108: pattern is listed in Table A.LI3. E
Page 109: 4.0 SOLUBILITY AND REACTION KINETIC
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Table 4.1 Experimental C
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Table 4.3 Standard slale properties
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Table 4.6 HKF equation ofstate coef
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Equilibrium constants are listed in
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Table 4.9 Equilbrium constants for
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Table 4.10 Standard state propertie
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lower NalP04 mole ratio than the re
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Broadbent D., Lewis G.G., and Wetto
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Marshall W.L. (1982) Two-liquid-pha
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Welton E.A.M. (1981) Phase equilibr
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APPENDIX I: Powder X-ray Diffractio
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TABLE A.l.l: X-Ray Diffraction Resu
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TABLE A,I.3 (continued) Quinlan JCP
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TABLE A.1.4 (continued) Quinlan (19
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TABLE A.l.S (continued) JCPDS Quinl
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TABLE A.1.6 (continued) Quinlan (19
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TABLE A.L8 (continued) Boudin JCPDS
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TABLE A.I.9 (continued) Product RGH
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TABLE A.I.IO (continued) Ziemniak a
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TABLE AJ.11 (continued) Zicmniak an
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TABLE A.T.I2 (continued) Zicmniak a
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TABLE A.I.13 (continued) Ziemniak a
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Experimental A colorless irrcg.plal
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Slfuc!ure Solution Refinemenl Funct
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111
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TABLE A.1II.1: Summary of ICP ES Re
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TABLE A.lll.2: KinclicData Time m(N
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TABLE A.III.2 (continued) Time m(Na
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TABLE A.lll.2 (continued) Time m(Na
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TABLE A.lIl.l (continued) Time m(Na
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TABLE A.III.3 (continued) t "C m(p0
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Canada - Memorial University of Newfoundland

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