A Thermodynamic Model for ZrO2(am) Solubility at 25°C in the Ca2+–Na+–H+–Cl−–OH−–H2O System: A Critical Review

A Thermodynamic Model for ZrO2(am) Solubility at 25°C in the... Zirconium is an important element in the nuclear fuel cycle. Thermodynamic data and models to reliably predict Zr–OH system behavior in various conditions including high ionic strengths are required and currently are unavailable. Most available experimental data are rather old, obtained using inadequate methodologies, and provide equilibrium constant values that differ by many orders of magnitude. Previous reviews have recommended values based on available data. These reviews used all of the available data, including poor quality data, in a global fit to determine these values. This has resulted in recommended thermodynamic models with a large number of polynuclear species and a number of mononuclear species with values of thermodynamic constants for the solubility product of ZrO2(am) and Zr–OH hydrolysis constants that are many orders of magnitude different from those for the reliable analogous Hf reactions. In this critical review, we have evaluated the quality of the available data, selected only those data that are of high quality, and reinterpreted all of the high quality data using SIT and Pitzer models for applications to high ionic strength solutions. Herein for 25 °C we (1) present formation constant values for ZrOH3+, $$ {\text{Zr}}\left( {\text{OH}} \right)_{2}^{2 + } $$ Zr OH 2 2 + , Zr(OH)4(aq), $$ {\text{Zr}}\left( {\text{OH}} \right)_{5}^{ - } $$ Zr OH 5 - , and $$ {\text{Zr}}\left( {\text{OH}} \right)_{6}^{2 - } $$ Zr OH 6 2 - , and the solubility product for ZrO2(am) which are consistent with the Hf system, (2) report a revised value for the formation constant of $$ {\text{Ca}}_{3} {\text{Zr}}\left( {\text{OH}} \right)_{6}^{4 + } $$ Ca 3 Zr OH 6 4 + , (3) show that several hypothetical polynuclear species ( $$ {\text{Zr}}_{3} \left( {\text{OH}} \right)_{9}^{3 + } $$ Zr 3 OH 9 3 + , Zr4(OH) 15 + , and Zr4(OH)16(aq)) proposed in previous reviews are not needed, and (4) show that polynuclear species ( $$ {\text{Zr}}_{3} \left( {\text{OH}} \right)_{4}^{8 + } $$ Zr 3 OH 4 8 + and $$ {\text{Zr}}_{4} \left( {\text{OH}} \right)_{8}^{8 + } $$ Zr 4 OH 8 8 + ) are not important in a very extensive H+ concentration range (0.1–10−15.4 mol·kg−1). Our review has also resulted in SIT and Pitzer ion-interaction parameters applicable to as high ionic strength solutions as 5.6 mol·kg−1 in NaCl, 2.11 mol·kg−1 in CaCl2, and 23.5 mol·kg−1 in NaOH. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Solution Chemistry Springer Journals

A Thermodynamic Model for ZrO2(am) Solubility at 25°C in the Ca2+–Na+–H+–Cl−–OH−–H2O System: A Critical Review

Loading next page...
 
/lp/springer_journal/a-thermodynamic-model-for-zro2-am-solubility-at-25-c-in-the-ca2-na-h-dIWBbGUw7f
Publisher
Springer Journals
Copyright
Copyright © 2018 by Springer Science+Business Media, LLC, part of Springer Nature
Subject
Chemistry; Physical Chemistry; Industrial Chemistry/Chemical Engineering; Geochemistry; Oceanography; Inorganic Chemistry; Condensed Matter Physics
ISSN
0095-9782
eISSN
1572-8927
D.O.I.
10.1007/s10953-018-0766-4
Publisher site
See Article on Publisher Site

Abstract

Zirconium is an important element in the nuclear fuel cycle. Thermodynamic data and models to reliably predict Zr–OH system behavior in various conditions including high ionic strengths are required and currently are unavailable. Most available experimental data are rather old, obtained using inadequate methodologies, and provide equilibrium constant values that differ by many orders of magnitude. Previous reviews have recommended values based on available data. These reviews used all of the available data, including poor quality data, in a global fit to determine these values. This has resulted in recommended thermodynamic models with a large number of polynuclear species and a number of mononuclear species with values of thermodynamic constants for the solubility product of ZrO2(am) and Zr–OH hydrolysis constants that are many orders of magnitude different from those for the reliable analogous Hf reactions. In this critical review, we have evaluated the quality of the available data, selected only those data that are of high quality, and reinterpreted all of the high quality data using SIT and Pitzer models for applications to high ionic strength solutions. Herein for 25 °C we (1) present formation constant values for ZrOH3+, $$ {\text{Zr}}\left( {\text{OH}} \right)_{2}^{2 + } $$ Zr OH 2 2 + , Zr(OH)4(aq), $$ {\text{Zr}}\left( {\text{OH}} \right)_{5}^{ - } $$ Zr OH 5 - , and $$ {\text{Zr}}\left( {\text{OH}} \right)_{6}^{2 - } $$ Zr OH 6 2 - , and the solubility product for ZrO2(am) which are consistent with the Hf system, (2) report a revised value for the formation constant of $$ {\text{Ca}}_{3} {\text{Zr}}\left( {\text{OH}} \right)_{6}^{4 + } $$ Ca 3 Zr OH 6 4 + , (3) show that several hypothetical polynuclear species ( $$ {\text{Zr}}_{3} \left( {\text{OH}} \right)_{9}^{3 + } $$ Zr 3 OH 9 3 + , Zr4(OH) 15 + , and Zr4(OH)16(aq)) proposed in previous reviews are not needed, and (4) show that polynuclear species ( $$ {\text{Zr}}_{3} \left( {\text{OH}} \right)_{4}^{8 + } $$ Zr 3 OH 4 8 + and $$ {\text{Zr}}_{4} \left( {\text{OH}} \right)_{8}^{8 + } $$ Zr 4 OH 8 8 + ) are not important in a very extensive H+ concentration range (0.1–10−15.4 mol·kg−1). Our review has also resulted in SIT and Pitzer ion-interaction parameters applicable to as high ionic strength solutions as 5.6 mol·kg−1 in NaCl, 2.11 mol·kg−1 in CaCl2, and 23.5 mol·kg−1 in NaOH.

Journal

Journal of Solution ChemistrySpringer Journals

Published: May 25, 2018

References

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off