Hydrolysis, formation and ionization constants at 25/sup 0/C, and at high temperature-high ionic strength

Phillips, S.L.; Phillips, Christine A.; Skeen, J.

doi:10.2172/5911914

Cited by 16 publications

(20 citation statements)

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“…Significant differences among the three cases simulated can be seen at early times when Eh values are close to the initial value assumed for the spatial domain. Tables Table 1. Composition of initial and influent solutions H20=H++OH--13.99 [6] ,.…”

Section: Resultsmentioning

confidence: 99%

“…10.09 [6] uo~+ + 2coi-= uo2(C0 3 )~-17.13 [6] uo~+ + 3Coi-= uo2(C0 3 );-20.64 [6] U02(0Hh · H20( c)+ 2H+ = UO~+ + 3H20 5.40 [7] Ca(U0 2 h(Si0 3 0H) 2 (c) + 6H+ = Ca 2 + + 2UO~+ + 2Si(OH)~ 17.21 [7] U02C03(c) = uo~+ + coi--14.29 [6] CaU04( c) + 4H+ = Ca 2 + + Uo~+ + 2H20 15.00 [8] USi04(c) + 2H20 = Uo~+ + Si(OH)~ + 2e--18.54 [7] U02(c) ·= uo~+ + 2e--13.19 [6] used in case 1: 2UO~+ + Coi-+ 3H20 = (U0 2 hC03(0H)3 + 3H+ -1.92 [6] uo~+ + e-= uot 2.11 {6]…”

Section: Resultsmentioning

confidence: 99%

“…Instead, reliance was placed on existing compilations (6,7,8] of equilibrium constants for reactions of interest, supplemented by a selection of data from the more recent literature. In order to keep the sensitivity analyses relatively uncomplicated, 1 attention was focused on equilibria involving the aqueous species U(OH)~, U(OH)5, uot, · (U0 2 hC03(0H)3, U02(C0 3 )~-, and U(C0 3 )~-.…”

Section: Some Differences In Uranium Data Basesmentioning

confidence: 99%

“…The older literature, compiled in [6], contains formation constants for a series of hydrolysis products of U(IV) including U(OH)~ and U(OH)5. The work [9,10] upon which these constants are based, as well as the existence of U(OH)5, has been questioned [11].…”

Section: Some Differences In Uranium Data Basesmentioning

confidence: 99%

“…When necessary, published values of equilibrium constants have been corrected to zero ionic strength by use of an extended Debye-Hiickel equation [6].…”

Section: Some Differences In Uranium Data Basesmentioning

confidence: 99%

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Some Effects of Data Base Variations on Numerical Simulations of Uranium Migration

Carnahan¹

1988

Radiochimica Acta

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Numerical simulations of migration of chemicals in the geosphere depend on knowledge of identities of chemical species and on values of chemical equilibrium constants supplied to the simulators. In this work, some effects of variability in assumed speciation and in equilibrium constants were examined, using migration of uranium as an example. Various simulations were done of uranium migration in systems with varying oxidation potential, pH, and major component content. A simulation including formation of aqueous species UO~+, U02COg, U02(C0 3 );-, U02(C0 3 )~-, (U0 2 ) 2 C03(0H);, UOt, U(OH)~, and U(OH)~ is compared to a simulation excluding formation of UOt and U(OH)~. These simulations relied on older data bases, and they are compared to a further simulation using recently published data on formation of U(OH)~, (U0 2 hC03(0H);, U02(C0 3 )~-, and U(C0 3 )~-. Significant differences in dissolved uranium concentrations are noted among the simulations. Differences are noted also in precipitation of two solids, USi0 4 (c) (coffinite) and CaU0 4 (c) (calcium uranate), although the solubility products of the solids were not varied in the simulations.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Some Differences In Uranium Data Basesmentioning

confidence: 99%

Section: Some Differences In Uranium Data Basesmentioning

confidence: 99%

“…When necessary, published values of equilibrium constants have been corrected to zero ionic strength by use of an extended Debye-Hiickel equation [6].…”

Section: Some Differences In Uranium Data Basesmentioning

confidence: 99%

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