Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate
Thermodynamic modelling of a leaching system that involves concurrent precipitation depends on an understanding of how the metals distribute into the precipitate before an assessment of solubility can be made. It has been suggested in the past that a pair of rare earths (A and B) in solution will se...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2020-08-01
|
| Series: | Minerals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-163X/10/8/712 |
| _version_ | 1797558788406902784 |
|---|---|
| author | Harry Watts Yee-Kwong Leong |
| author_facet | Harry Watts Yee-Kwong Leong |
| author_sort | Harry Watts |
| collection | DOAJ |
| description | Thermodynamic modelling of a leaching system that involves concurrent precipitation depends on an understanding of how the metals distribute into the precipitate before an assessment of solubility can be made. It has been suggested in the past that a pair of rare earths (A and B) in solution will separate from each other by oxalate precipitation according to a logarithmic distribution coefficient (<inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula>), determined by the kinetics of the precipitation. By contrast, the present study hypothesises that <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula> may be approximated from thermodynamic terms, including the solubility product (K<sub>Sp</sub>) of each rare earth oxalate and the stability constant (<inline-formula><math display="inline"><semantics><mrow><msub><mi mathvariant="sans-serif">β</mi><mn>1</mn></msub><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> for the mono-oxalato complex of each rare earth. The proposed model was used to calculate <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula> between pairs of rare earths. An experimental study was conducted to determine <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula> between selected pairs using homogenous precipitation through the hydrolysis of an oxalic acid ester, with fairly close agreement to the values under the proposed model. Though this model requires more thorough testing, as well as application to other organic salts, it may provide insight into distribution factors of a precipitate formed by a sequence of organic complexes. |
| first_indexed | 2024-03-10T17:35:16Z |
| format | Article |
| id | doaj.art-33051a7d7bf442a6bfa833a0b7e07a37 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-10T17:35:16Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-33051a7d7bf442a6bfa833a0b7e07a372023-11-20T09:51:42ZengMDPI AGMinerals2075-163X2020-08-0110871210.3390/min10080712Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed OxalateHarry Watts0Yee-Kwong Leong1Department of Chemical Engineering, University of Western Australia, Crawley, WA 6009, AustraliaDepartment of Chemical Engineering, University of Western Australia, Crawley, WA 6009, AustraliaThermodynamic modelling of a leaching system that involves concurrent precipitation depends on an understanding of how the metals distribute into the precipitate before an assessment of solubility can be made. It has been suggested in the past that a pair of rare earths (A and B) in solution will separate from each other by oxalate precipitation according to a logarithmic distribution coefficient (<inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula>), determined by the kinetics of the precipitation. By contrast, the present study hypothesises that <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula> may be approximated from thermodynamic terms, including the solubility product (K<sub>Sp</sub>) of each rare earth oxalate and the stability constant (<inline-formula><math display="inline"><semantics><mrow><msub><mi mathvariant="sans-serif">β</mi><mn>1</mn></msub><mo stretchy="false">)</mo></mrow></semantics></math></inline-formula> for the mono-oxalato complex of each rare earth. The proposed model was used to calculate <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula> between pairs of rare earths. An experimental study was conducted to determine <inline-formula><math display="inline"><semantics><mi mathvariant="sans-serif">λ</mi></semantics></math></inline-formula> between selected pairs using homogenous precipitation through the hydrolysis of an oxalic acid ester, with fairly close agreement to the values under the proposed model. Though this model requires more thorough testing, as well as application to other organic salts, it may provide insight into distribution factors of a precipitate formed by a sequence of organic complexes.https://www.mdpi.com/2075-163X/10/8/712rare earthsdistribution factorselective precipitationoxalatesorganic complexes |
| spellingShingle | Harry Watts Yee-Kwong Leong Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate Minerals rare earths distribution factor selective precipitation oxalates organic complexes |
| title | Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate |
| title_full | Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate |
| title_fullStr | Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate |
| title_full_unstemmed | Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate |
| title_short | Predicting the Logarithmic Distribution Factors for Coprecipitation into an Organic Salt: Selection of Rare Earths into a Mixed Oxalate |
| title_sort | predicting the logarithmic distribution factors for coprecipitation into an organic salt selection of rare earths into a mixed oxalate |
| topic | rare earths distribution factor selective precipitation oxalates organic complexes |
| url | https://www.mdpi.com/2075-163X/10/8/712 |
| work_keys_str_mv | AT harrywatts predictingthelogarithmicdistributionfactorsforcoprecipitationintoanorganicsaltselectionofrareearthsintoamixedoxalate AT yeekwongleong predictingthelogarithmicdistributionfactorsforcoprecipitationintoanorganicsaltselectionofrareearthsintoamixedoxalate |