Precipitation stripping of lanthanum and neodymium

Zieliński, S.; Buca, Marek; Szczepanik, Anna

doi:10.1016/0304-386x(91)90034-j

Cited by 7 publications

(2 citation statements)

References 2 publications

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“…Algunos ejemplos de utilización de esta técnica de separación se tienen en la precipitación de lantano y neodimio de una fase orgánica de DEHPA en queroseno (42). La disolución sulfúrica de reextracción contenía un sulfato (sódico, potásico o amóni-co) como agente precipitante.…”

Section: Precipitación (En Ia Etapa De Reextracción)unclassified

Procesos de separación de las tierras raras

Rodríguez¹

1997

REVMETAL

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Resumen Los elementos pertenecientes al grupo de las tierras raras presentan un comportamiento peculiar, consistente en que sus propiedades parecidas hacen que su separación con los procedimientos convencionales no sea fácil. Este hecho, unido a las condiciones de alta pureza que su uso práctico demanda, han llevado al desarrollo de nuevas tecnologías que permiten la separación y obtención de estos elementos en condiciones de pureza elevada. En el presente trabajo se revisan algunos de los resultados obtenidos con la aplicación se estas tecnologías en la separación y purificación de las tierras raras.Palabras clave: Tierras raras. Procesos de separación. Separation processes in rare earths AbstractThe rare earth elements are unique in its behaviour, its similar properties make very difficult its separation by conventional procedures, this linked to the necessity to obtain high grade final producís, as demanded by modern industry, had led to the develop of new technologies that allow the final goal of the utilization of these rare elements: the separation and obtention of products which cope the demands of its uses are needed for. The present work revised some of the applications of these technologies in the separation and purification of rare earths.Keywords: Rare earths. Separation processes. INTRODUCCIÓNAl grupo de las tierras raras pertenecen una serie de elementos que son muy difíciles de separar mediante las técnicas tradicionales, ya que poseen propiedades químicas muy parecidas.Estas primeras técnicas utilizaban recristalizaciones múltiples y fraccionadas, operaciones que necesitaban la recirculación de muchas corrientes hasta obtener productos con una pureza adecuada.La mayor demanda de estos elementos metálicos en la industria moderna, especialmente para diversas tecnologías avanzadas, ha necesitado la obtención de estos metales en un estado muy puro, imposible de alcanzar con las técnicas convencionales, por lo que se ha llevado a cabo un esfuerzo investigador y de desarrollo importante en los distintos campos sobre obtención y recuperación de las tierras raras de los diferentes recursos minerales que las contienen (como la monacita, bastaensita, xenotima y euxenita), e incluso, sobre el procesado de otros metales de los que es posible obtener estos elementos como productos secundarios (1-5). Las tierras raras presentes en los minerales que las contienen o en otros recursos secundarios se pueden lixiviar en distintos medios acuosos, por ejemplo: en nitrato, sulfato y cloruro. El primer elemento que pertenece a este grupo se descubrió en 1794. La tabla I muestra la lista cronológica del descubrimiento de las distintas tierras raras junto a su radio iónico estimado (6 y 7). PROCESOS DE SEPARACIÓN Separación fotoquímicaMediante esta técnica, se ha estudiado la separación de europio de otras tierras raras (8). Se empleó como fuente de excitación una lámpara de mercurio de baja presión, con una longitud de onda de 185 nm. Las tierras raras estaban presentes en una concentración de 0,01M (como percloratos bi...

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Section: Precipitación (En Ia Etapa De Reextracción)unclassified

Procesos de separación de las tierras raras

Rodríguez¹

1997

REVMETAL

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“…177 Cahill and Burkhart discussed the selective precipitation of uranium peroxide from high-vanadium solutions. 178 Sullivan and coworkers investigated the effect of AI, Mg, and Fe on the solubility of a-calcium sulfate hemihydrate in phosphoric acid solutions at varying concentrations and temperature.…”

Section: Precipitation and Crystallization Processesmentioning

confidence: 99%

Aqueous processing of minerals, metals, and materials

Doyle

Duyvesteyn

1993

JOM

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Authors' Note: This article reviews research published or presented in 1991 and 1992 that we feel is likely to be of interest to those involved in hydrometallurgy and the aqueous processing of materials and industrial minerals. It is beyond the scope of such a review to discuss any of the contributions comprehensively or critically. Instead, we hope that the reader will use this compilation of recent research as an information sourceiand learn more about work that heor she is interested in from the references given here. GENERAL SYMPOSIATwo international symposia held in 1992 covered a comprehensive range of hydrometallurgical research. The Ernest Peters International Symposium on Hydrometallurgy, Theory and Practice, had sessions on leaching of ores and concentrates, hydrometallurgical deSign, simulation and process control, hydrometallurgical process innovation, hydrometallurgy and the environment, hydrometallurgy and precious metals recovery, and solution purification. 1 The Second International Conference on Hydrometallurgy, held in Changsha, China, included ten plenary lectures with an emphasis on Chinese hydrometallurgy, but speakers also addressed aspects of heap leaching, integrated waste management, solvent extraction, and the use of liquid membranes for effluent treatment. The plenary lectures were followed by sessions on general hydrometallurgy (27 papers), leaching (37 papers), precious metals (29 papers), purification and separation (59 papers), and environmental problems (26 papers).2 PHYSICAL CHEMISTRY OF AQUEOUS SYSTEMSThe power of thermodynamic analysis for understanding the behavior of aqueous systems has long been recognized. Over the last few years, however, computational techniques have greatly facilitated such analyses. A recent example is the construction of multicomponent Eh-pH diagrams, using generalized species. 3 However, the computations are only as good as the data that are used as inputto models. Duffield and coworkers discussed the critical appraisal of thermodynamic data for use with computer-based chemical speciation models, the problems associated with selecting formation/ dissolution constants for solids, and the interpretation of c0l!lputed results.+-;;For many systems there is still an urgent need for good thermodynamic data, 46 and recent contributions in this area are particularlywekome. Indu and coworkers developed a scale characterizing the acidity of solutions containing H 2 SO 4 and Na 2 SO/ The activities and osmotic coefficients of various alkali and alkalineearth halide solutions were calculated from vapor pressure measurements,8 freezing pOint data (using a two-parameter equation of the Huckel type),9

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Recovery of lanthanides from kola apatite in phosphoric acid manufacture

Zieliński

Szczepanik

Buca

et al. 1993

J of Chemical Tech & Biotech

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Abstract:The paper presents the results of bench-scale studies for the recovery of lanthanides from Kola apatite in the phosphoric acid production by a two-stage hemihydrate-dihydrate wet-process. The second stage of the process (hydration of hemihydrate) provides the best conditions for the recovery of lanthanides. In the postulated recovery process use is made of solvent extraction for the removal of lanthanides during hydration of hemihydrate, and precipitation-stripping for the removal of lanthanides from the solvent. Lanthanides are recovered in the form of Ln-enriched concentrates with an efficiency of 80435%. The process does not disturb the phosphoric acid production, and additionally purifies the by-product gypsum, so that it can be utilized.

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Precipitation stripping of lanthanum and neodymium

Cited by 7 publications

References 2 publications

Procesos de separación de las tierras raras

Procesos de separación de las tierras raras

Aqueous processing of minerals, metals, and materials

Recovery of lanthanides from kola apatite in phosphoric acid manufacture

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