Solubility of NaNd(CO3)2.6H2O(c) in Mixed Electrolyte (Na-Cl-CO3-HCO3) and Synthetic Brine Solutions

Rao, Linfeng; Rai, Dhanpat; Felmy, Andrew R.; Novak, Craig F.

doi:10.1007/978-1-4419-8690-0_9

Cited by 4 publications

(10 citation statements)

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“…The generated precipitate was confirmed to be NaNd(CO 3 ) 2 (see Section 2.1.4 and the FTIR result in Figure 6). According to the solubility product of NaNd(CO 3 ) 2 (log K sp was −21.39), 15 for the reactionunder the experimental condition, the concentration of sodium carbonate was 1, 1.5, and 2 mol·L –1 and the activity coefficient of sodium carbonate was calculated to be 0.236, 0.205, and 0.188 via Pitzer theory, 19 respectively. Then, the corresponding concentration of Nd 3+ in equilibrium was evaluated, and it should be 1.563 × 10 –19 , 1.911 × 10 –19 , and 2.450 × 10 –19 g·L –1 .…”

Section: Results and Discussionmentioning

confidence: 99%

“…Moreover, the ionic strength of the carbonate solution could also affect the dissolution process of the rare earth. Rao et al 15 investigated the chemical balance behaviors of Nd 3+ in the solution system of Na + –Cl – –CO 3 2– –HCO 3 – and found that at the same concentration of sodium carbonate, the dissolution amount of rare earth was enhanced with the existence of impurity salt sodium chloride, compared to without sodium chloride. The higher the concentration of sodium chloride, the more is the amount of rare earth dissolved.…”

Section: Introductionmentioning

confidence: 99%

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Metastable Dissolution Regularity of Nd³⁺ in Na₂CO₃ Solution and Mechanism

Yang

Zhang

et al. 2019

ACS Omega

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The carbonate solution-dissolved rare earth showed some metastable chemical characteristics. In this paper, the systematic investigation of metastable dissolution regularity of Nd 3+ in Na 2 CO 3 solution was carried out. The results showed that Nd 3+ has an instantaneous saturated solubility in Na 2 CO 3 solution. When the amount of the dissolution Nd 3+ did not reach the instantaneous saturated solubility, the solution was in a stable-state period. Once the concentration of Nd 3+ exceeded the instantaneous saturated solubility, the solution was no longer in the metastable state and generated the neodymium double salt of carbonate precipitates rapidly. The molecular dynamics simulation of the solution in the metastable state was carried out. In high concentration Na 2 CO 3 solution, dissolved Nd 3+ had a coordination reaction with the CO 3 2– . Also, there was a stronger interaction between Na + and CO 3 2– , which caused the effective concentration of free CO 3 2– which could react with Nd 3+ to become lower. Thus, these reasons make the solution exhibit a metastable state. In that metastable period, the dissolved Nd 3+ becomes steady and hard to generate the neodymium double salt of carbonate precipitates.

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Section: Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Metastable Dissolution Regularity of Nd³⁺ in Na₂CO₃ Solution and Mechanism

Yang

Zhang

et al. 2019

ACS Omega

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“…The suspensions containing the PuO 2 (am) were centrifuged, and the supernatant solutions were removed. The precipitates were washed with 20-mL aliquots of distilled deionized water and suspended in 30 suspensions were adjusted to a range varying from about 3 to 10. The centrifuge tubes containing the suspensions were capped tightly and shaken continuously at room temperature (21 ± 2 • C) until they were analyzed.…”

Section: Methodsmentioning

confidence: 99%

“…For this purpose, PuO 2 (am) solubility was determined under N 2 (gas) atmosphere in a synthetic solution (ERDA6B with 5.31 m NaCl as the major component; described by Rao et al [30]), which is representative of a brine from the Waste Isolation Pilot Project (WIPP). A close agreement exists between our predicted, using the data in Table 1 and other assumptions discussed in the paper, and measured Pu concentrations [log(C Pu(V) /mol kg −1 ) values of − 5.94 and − 5.83 measured after 8 days of equilibration, and − 5.93 and − 5.78 predicted, for pc H + values of 6.46 and 6.38, respectively], indicating the usefulness of the model de- Table 1 and other assumptions discussed in the text.…”

Section: Final Modelmentioning

confidence: 99%

Thermodynamics of the PuO₂⁺-Na⁺-OH^--Cl^--ClO₄^--H₂O system: use of NpO₂⁺Pitzer parameters for PuO₂⁺

Rai¹,

Moore²,

Felmy³

et al. 2001

Radiochimica Acta

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PuO 2 (am) / Radiolysis / PuO 2 + / PuO 2 2+ / Solubility / Thermodynamics / Pitzer model / Actinides Summary. Obtaining reliable thermodynamic data for Pu(V) is difficult because of its redox and/or disproportionation reactions in most aqueous systems. The known stability of Pu(V) in PuO 2 (am) suspensions in slightly acidic to near neutral conditions was used to study the solubility of PuO 2 (am) in 0.4 and 4.0 M NaCl or NaClO 4 solutions ranging in pc H + values from 4 to 9 as a function of time. The close agreement between the observed solubility and the predicted solubility using Pitzer ion-interaction parameters of Np(V) with Cl − or ClO 4 − for Pu(V) indicates that Pu(V), as expected, behaves in an analogous fashion to Np(V) and confirms the value of using Np(V) data to model Pu(V) behavior.

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“…In addition, it was also found that the concentration of NH 4 + influenced the dissolution behavior of rare earth in the solution system in that a higher concentration of NH 4 + could enhance the solubility of rare earths. Reference to research on the equilibrium hydrochemical behavior of neodymium in a Na + -Cl − -CO 3 2− -HCO 3 − solution system [11], shows that there is a relationship between the solubility of rare earth in a carbonate solution and the concentration of the NaCl salt as an impurity, and the dissolved amount of rare earth increases with increasing concentration of NaCl in the solution. High concentration of NaCl results in high ionic strength of the solution.…”

Section: Introductionmentioning

confidence: 99%

Maintenance of the Metastable State and Induced Precipitation of Dissolved Neodymium (III) in an Na2CO3 Solution

Yang

Zhang

et al. 2021

Minerals

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Rare earths dissolved in carbonate solutions exhibit a metastable state. During the period of metastability, rare earths dissolve stably without precipitation. In this paper, neodymium was chosen as a representative rare earth element. The effects of additional NaCl and CO2 on the metastable state were investigated. The metastable state can be controlled by adding NaCl to the Na2CO3 solution. Molecular dynamics studies indicated that the Cl− provided by the additional NaCl partially occupied the coordination layer of Nd3+, causing the delayed formation of neodymium carbonate precipitation. In addition, the additional NaCl decreased the concentration of free carbonate in the solution, thereby reducing the behavior of free contact between carbonate and Nd, as well as resulting in the delay of Nd precipitate formation. Consequently, the period of the metastable state was prolonged in the case of introduction of NaCl. However, changing the solution environment by introducing CO2 can destroy the metastable state rapidly. Introduction of CO2 gas significantly decreased the CO32− content in the solution and increased its activity, resulting in an increase of the free CO32− concentration of the solution in the opposite direction. As a result, the precipitation process was accelerated and the metastable state was destroyed. It was possible to obtain a large amount of rare earth carbonate precipitation in a short term by introducing CO2 into the solution with dissolved rare earths in the metastable state to achieve rapid separation of rare earths without introducing other precipitants during the process.

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Solubility of NaNd(CO3)2.6H2O(c) in Mixed Electrolyte (Na-Cl-CO3-HCO3) and Synthetic Brine Solutions

Cited by 4 publications

References 20 publications

Metastable Dissolution Regularity of Nd³⁺ in Na₂CO₃ Solution and Mechanism

Metastable Dissolution Regularity of Nd³⁺ in Na₂CO₃ Solution and Mechanism

Thermodynamics of the PuO₂⁺-Na⁺-OH^--Cl^--ClO₄^--H₂O system: use of NpO₂⁺Pitzer parameters for PuO₂⁺

Maintenance of the Metastable State and Induced Precipitation of Dissolved Neodymium (III) in an Na2CO3 Solution

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Solubility of NaNd(CO3)2.6H2O(c) in Mixed Electrolyte (Na-Cl-CO3-HCO3) and Synthetic Brine Solutions

Cited by 4 publications

References 20 publications

Metastable Dissolution Regularity of Nd3+ in Na2CO3 Solution and Mechanism

Metastable Dissolution Regularity of Nd3+ in Na2CO3 Solution and Mechanism

Thermodynamics of the PuO2+-Na+-OH--Cl--ClO4--H2O system: use of NpO2+Pitzer parameters for PuO2+

Maintenance of the Metastable State and Induced Precipitation of Dissolved Neodymium (III) in an Na2CO3 Solution

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Metastable Dissolution Regularity of Nd³⁺ in Na₂CO₃ Solution and Mechanism

Metastable Dissolution Regularity of Nd³⁺ in Na₂CO₃ Solution and Mechanism

Thermodynamics of the PuO₂⁺-Na⁺-OH^--Cl^--ClO₄^--H₂O system: use of NpO₂⁺Pitzer parameters for PuO₂⁺