caa a22 4500 378927256 CHVBK 20180305123620.0 cr unu---uuuuu 161128e20041101xx s 000 0 eng 10.1524/ract.92.9.537.54983 doi (NATIONALLICENCE)gruyter-10.1524/ract.92.9.537.54983 Solubility and colloid formation of Th(IV) in concentrated NaCl and MgCl2 solution [Elektronische Daten] [M. Altmaier, Volker Neck, Thomas Fanghänel] The solubility of crystalline ThO2(cr) and amorphous hydrated Th(IV) oxyhydroxide ThOn(OH)4-2n·xH2O(am) has been measured in dilute to concentrated NaCl and MgCl2 solutions equilibrated with magnesium hydroxide or hydroxychloride at 22±2°C. The contributions of colloids to the total thorium concentrations observed in both over- and undersaturation experiments with amorphous Th(IV) precipitates have been analysed by ultracentrifugation. The solubility increasing effect of long-time stable Th(IV) eigencolloids, previously investigated in 0.5M NaCl solutions, is also observed in concentrated 5M NaCl. Ionic strength and chloride concentration have no effect on the stability of these hydrophilic Th(IV) oxyhydroxide eigencolloids, which are the predominant species in solution. They cause relatively high total thorium concentration in neutral to alkaline steady state solutions, independent of ionic strength: log[Th]tot≈log[Th]coll=-6.3±0.5. In concentrated MgCl2 solutions saturated with magnesium hydroxychloride colloids, the formation of pseudocolloids, i.e., Th(IV) sorbed onto Mg2(OH)3Cl·4H2O(coll), leads to a further increase of the total thorium concentration up to 10-5M. The present results are discussed with regard to maximum Th(IV) and Pu(IV) concentrations in performance assessment calculations. © 2004 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Altmaier M. aut Neck Volker aut Fanghänel Thomas aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/9-11/2004(2004-11-01), 537-543 0033-8230 92:9-11/2004<537 2004 92 ract https://doi.org/10.1524/ract.92.9.537.54983 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.92.9.537.54983 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Altmaier M. aut NATIONALLICENCE 700 1- Neck Volker aut NATIONALLICENCE 700 1- Fanghänel Thomas aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/9-11/2004(2004-11-01), 537-543 0033-8230 92:9-11/2004<537 2004 92 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter