<abstract xmlns="http://www.w3.org/1999/xhtml">

Search for inexpensive and efficient methods of critical raw materials recovery is of great importance across the world due to growing demand for green technologies. Formation and detailed characterization of new Pb- and Light Rare Earth Elements (LREE)-containing phosphates, compared to already described Pb- or LREE-containing phosphates, was described in this work. These phases were precipitated at experimental conditions similar to these used in a newly proposed coprecipitation route for REE recovery from aqueous solutions. The formation of La, Ce, Pr and Sm phosphates from aqueous solutions proceeded differently in the presence of Pb than in its absence. No rhabdophane group minerals, (REE,Ca,Th)(PO4)·<italic>n</italic>H2O were formed, which were the product of crystallization in the absence of Pb, as evidenced by the PXRD analysis of the control LREE phosphates. Instead, a new, distinct phase was formed, which is neither a ‘phosphoschultenite’, PbHPO4, with La, Ce, Pr or Sm substitution nor a rhabdophane with Pb substitution. This showed that PbHPO4 structure did not accept isomorphic substitutions of LREE elements and rhabdophane structures are reluctant to accept Pb substitutions. At the same time, the formation of a hitherto unknown crystalline phase was found to be a mixed (LREE,Pb)-phosphate. A lower pH caused higher crystallinity of phases, as confirmed by SEM and PXRD. FTIR spectroscopy showed the hydrous nature of the obtained phases, which was additionally confirmed by thermal analysis. Decreasing pH of the reaction solution resulted in a higher crystalline water content. Moreover, La-bearing phases contained more chemically bound water than other phases. A combined EDS analysis and ICP-OES led to the chemical composition of new Pb phases with La, Ce, Pr and Sm that can be expressed as La2Pb3(PO4)4·3.5H2O, Ce2Pb3(PO4)4·3.3H2O, Pr2Pb3(PO4)4·3.1H2O and Sm2Pb3(PO4)4·3.3H2O, respectively. These results give a better understanding of potential novel recovery pathways of REE from phosphate mineral sources or wastes.
</abstract>

Search for inexpensive and efficient methods of critical raw materials recovery is of great importance across the world due to growing demand for green technologies. Formation and detailed characterization of new Pb- and Light Rare Earth Elements (LREE)-containing phosphates, compared to already described Pb- or LREE-containing phosphates, was described in this work. These phases were precipitated at experimental conditions similar to these used in a newly proposed coprecipitation route for REE recovery from aqueous solutions. The formation of La, Ce, Pr and Sm phosphates from aqueous solutions proceeded differently in the presence of Pb than in its absence. No rhabdophane group minerals, (REE,Ca,Th)(PO4)·nH2O were formed, which were the product of crystallization in the absence of Pb, as evidenced by the PXRD analysis of the control LREE phosphates. Instead, a new, distinct phase was formed, which is neither a ‘phosphoschultenite’, PbHPO4, with La, Ce, Pr or Sm substitution nor a rhabdophane with Pb substitution. This showed that PbHPO4 structure did not accept isomorphic substitutions of LREE elements and rhabdophane structures are reluctant to accept Pb substitutions. At the same time, the formation of a hitherto unknown crystalline phase was found to be a mixed (LREE,Pb)-phosphate. A lower pH caused higher crystallinity of phases, as confirmed by SEM and PXRD. FTIR spectroscopy showed the hydrous nature of the obtained phases, which was additionally confirmed by thermal analysis. Decreasing pH of the reaction solution resulted in a higher crystalline water content. Moreover, La-bearing phases contained more chemically bound water than other phases. A combined EDS analysis and ICP-OES led to the chemical composition of new Pb phases with La, Ce, Pr and Sm that can be expressed as La2Pb3(PO4)4·3.5H2O, Ce2Pb3(PO4)4·3.3H2O, Pr2Pb3(PO4)4·3.1H2O and Sm2Pb3(PO4)4·3.3H2O, respectively. These results give a better understanding of potential novel recovery pathways of REE from phosphate mineral sources or wastes.

New synthetic [LREE (LREE = La, Ce, Pr, Sm), Pb]-phosphate phases

Mineralogia

This work is licensed under the Creative Commons Attribution 4.0 International License.

{"article-title":"New synthetic [LREE (LREE = La, Ce, Pr, Sm), Pb]-phosphate phases"}

Search for inexpensive and efficient methods of critical raw materials recovery is of great importance across the world due to growing demand for green...

New synthetic [LREE (LREE = La, Ce, Pr, Sm), Pb]-phosphate phases

Article Category: Original Paper

Publié en ligne: 19 déc. 2023

Pages: 58 - 68

Reçu: 30 mai 2023

Accepté: 13 nov. 2023

DOI: https://doi.org/10.2478/mipo-2023-0006

Mots clés
REE phosphates, lead phosphates, rhabdophane, ‘phosphoschultenite’, monazite

© 2023 Kacper Staszel et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

New synthetic [LREE (LREE = La, Ce, Pr, Sm), Pb]-phosphate phases

Article Category: Original Paper

Publié en ligne: 19 déc. 2023

Pages: 58 - 68

Reçu: 30 mai 2023

Accepté: 13 nov. 2023

DOI: https://doi.org/10.2478/mipo-2023-0006

Mots clésREE phosphates, lead phosphates, rhabdophane, ‘phosphoschultenite’, monazite

© 2023 Kacper Staszel et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Mots clés
REE phosphates, lead phosphates, rhabdophane, ‘phosphoschultenite’, monazite