Formation of titanium phosphate composites during phosphoric acid decomposition of natural sphene

Journal Article · Mon Dec 15 00:00:00 EST 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.09.007· OSTI ID:21212145

Maslova, Marina V ^[1]; Rusanova, Daniela ^[2]; Naydenov, Valeri ^[3]; Antzutkin, Oleg N ^[2]; Gerasimova, Lidia G ^[1]

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1. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials, Kola Science Centre, Russian Academy of Sciences, Fersman st. 26a, Apatity, Murmansk Region 184209 (Russian Federation)
2. Division of Chemistry, Department of Chemical Engineering and Geosciences, Lulea University of Technology, 97187 Lulea (Sweden)
3. SunPine AB, Box 76, 941 22 Pitea (Sweden)

Decomposition of mineral sphene, CaTiOSiO{sub 4}, by H{sub 3}PO{sub 4} is investigated in detail. During the dissolution process, simultaneous calcium leaching and formation of titanium phosphate (TiP) take place. The main product of decomposition is a solid titanium phosphate-silica composite. The XRD, solid-sate NMR, IR, TGA, SEM and BET data were used to identify and characterize the composite as a mixture of crystalline Ti(HPO{sub 4}){sub 2}.H{sub 2}O and silica. When 80% phosphoric acid is used the decomposition degree is higher than 98% and calcium is completely transferred into the liquid phase. Formation of Ti(HPO{sub 4}){sub 2}.H{sub 2}O proceeds via formation of meta-stable titanium phosphate phases, Ti(H{sub 2}PO{sub 4})(PO{sub 4}).2H{sub 2}O and Ti(H{sub 2}PO{sub 4})(PO{sub 4}). The sorption affinities of TiP composites were examined in relation to caesium and strontium ions. A decrease of H{sub 3}PO{sub 4} concentration leads to formation of composites with greater sorption properties. The maximum sorption capacity of TiP is observed when 60% H{sub 3}PO{sub 4} is used in sphene decomposition. The work demonstrates a valuable option within the Ti(HPO{sub 4}){sub 2}.H{sub 2}O-SiO{sub 2} composite synthesis scheme, to use phosphoric acid flows for isolation of CaHPO{sub 4}.2H{sub 2}O fertilizer. - Graphical abstract: A new synthesis scheme for preparation of composite titanium phosphate (TiP) ion-exchangers upon one-stage decomposition process of natural sphene with phosphoric acid is presented. Syntheses of {alpha}-TiP-silica composites proceed via formation of meta-stable titanium phosphate phases. The concentration of H{sub 3}PO{sub 4} determines the porosity of final products and their sorption affinities.

• OSTI ID: 21212145
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 12; Other Information: DOI: 10.1016/j.jssc.2008.09.007; PII: S0022-4596(08)00484-2; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CALCIUM SILICATES
DECOMPOSITION
ION EXCHANGE
LEACHING
NUCLEAR MAGNETIC RESONANCE
PHOSPHORIC ACID
SCANNING ELECTRON MICROSCOPY
SILICA
SILICON OXIDES
SORPTION
STRONTIUM IONS
SYNTHESIS
THERMAL GRAVIMETRIC ANALYSIS
TITANITE
TITANIUM PHOSPHATES
TITANIUM SILICATES
X-RAY DIFFRACTION