Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Recovery of rare earth elements from nitrophosphoric acid solutions
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.ORCID iD: 0000-0002-3239-5188
2017 (English)In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 169, p. 253-262Article in journal (Refereed) Published
Abstract [en]

In the present study, the recovery of rare earth elements (REEs) from an apatite concentrate in the nitrophosphate process of fertilizer production has been studied. The apatite concentrate has been recovered from iron ore tailings in Sweden by flotation. In the first step, the apatite is digested in concentrated nitric acid, after which Ca(NO3)2.4H2O is separated by cooling crystallization. The solution is then neutralized using ammonia whereby the REEs precipitate mainly as phosphates (REEPO4.nH2O) and together with calcium as REEn Cam (PO4)(3n + 2m) / 3. In this work, the degree of rare earth coprecipitation during seeded cooling crystallization of Ca(NO3)2.4H2O has been studied. The solubility of calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) in acidic nitrophosphoric acid solutions in the temperature range of − 2 °C to 20 °C has been determined. For the neutralization step, it is shown that the calcium concentration and the final pH play an important role in determining the concentration of REEs in the precipitate. It is found that reaching maximum recovery of REE with minimum simultaneous precipitation of calcium requires careful control of the final pH to about 1.8. It is further observed that the precipitation yield of REEs and iron is favored by a longer residence time and higher temperature. Finally, the effect of seeding with synthesized REE phosphate crystals as well as a mixture of REE and Ca phosphates on the precipitation rate and the composition of the precipitate was studied.

Place, publisher, year, edition, pages
Elsevier, 2017. Vol. 169, p. 253-262
Keywords [en]
Cooling crystallization, Nitrophosphate process, REE, Seeded precipitation, Selective precipitation, Apatite, Calcium, Cooling, Flotation, Iron ores, Metal recovery, Ore tailings, Ore treatment, Phosphate minerals, Phosphates, Rare earth elements, Rare earths, Recovery, Calcium nitrate tetra-hydrate, Concentrated nitric acid, Nitrophosphate, Rare earth elements (REEs), Simultaneous precipitation, Precipitation (chemical)
National Category
Materials Engineering
Identifiers
URN: urn:nbn:se:kth:diva-207347DOI: 10.1016/j.hydromet.2017.01.008ISI: 000401878200031Scopus ID: 2-s2.0-85011958720OAI: oai:DiVA.org:kth-207347DiVA, id: diva2:1097315
Funder
Swedish Foundation for Strategic Research , IRT 11-0026
Note

QC 20170522

Available from: 2017-05-22 Created: 2017-05-22 Last updated: 2017-06-19Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Alemrajabi, MahmoodRasmuson, Åke C.Korkmaz, KivancForsberg, Kerstin

Search in DiVA

By author/editor
Alemrajabi, MahmoodRasmuson, Åke C.Korkmaz, KivancForsberg, Kerstin
By organisation
Transport Phenomena
In the same journal
Hydrometallurgy
Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 285 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf