A New Synthetic Route to Pseudo-Brookite-Type CaTi2O4

Rogge, Matthew P.; Caldwell, John H.; Ingram, Dale R.; Green, Caryn E.; Geselbracht, Margret J.; Siegrist, T.

doi:10.1006/jssc.1998.7932

Cited by 36 publications

(24 citation statements)

References 12 publications

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“…It was shown that equimolar or titanium rich mixtures were needed to form the compound. Rogge et al [18] also observed that when the titanium powder oxidised to TiO, CaTi 2 O 4 was not formed, indicating that the comproportionation reaction probably has a small positive ∆G. Figure 3 shows that the formation of CaTi 2 O 4 at the inner layers closely coincides with the formation of titanium in the outer layers (0.6, -0.9 and 1.2 mm).…”

Section: Resultsmentioning

confidence: 88%

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In situ synchrotron diffraction of the electrochemical reduction pathway of TiO2

et al. 2010

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Despite over ten years of research into the low-cost electrowinning of titanium direct from the oxide, the reduction sequence of TiO 2 pellets in molten CaCl 2 has been the subject of debate, particularly as the reduction pathway has been inferred from ex-situ studies. Here, for the first time white beam synchrotron X-ray diffraction is used to characterize the phases that form, in-situ during reduction and with ∼100 µm spatial resolution. It is found that TiO 2 becomes sub-stoichiometric very early in reduction facilitating the ionic conduction of oxygen ions, that CaTiO 3 persists to nearly the end of the process and that, finally, CaO forms just before completion of the process. The method is quite generally applicable to the in-situ study of industrial chemical processes. Implications for the industrial scale-up of this method for the low-cost production of titanium are drawn.

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Section: Resultsmentioning

confidence: 88%

“…The conditions required to form CaTi 2 O 4 have been studied by Rogge et al [18]. CaTiO 3 and titanium metal powder were combined with a CaCl 2 flux at 1000 • C to form CaTi 2 O 4 .…”

Section: Resultsmentioning

confidence: 99%

In situ synchrotron diffraction of the electrochemical reduction pathway of TiO2

et al. 2010

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“…However, the excess amount of CaO may form the Ca-containing complex oxide with the residual oxide, such as CaTiO 3 and Ca 2 TiO 4 as the intermediate products [23][24][25] . Note that Ca 2 TiO 4 contains trivalent Ti and it can be grown only in CaCl 2 melt with metallic Ti 26) . The appearance of these Ca-containing complex oxides in the way of reduction is one of the proofs that the calciothermic reduction (OS process) is working.…”

Section: Reduction By Calciummentioning

confidence: 99%

Reduction of CaTiO<sub>3</sub> in Molten CaCl<sub>2</sub> - as Basic Understanding of Electrolysis

et al. 2017

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Electrochemical decomposition of CaTiO 3 at the cathode was examined in a scheme of titanium metal production from natural deposit, Ilmenite (TiFeO 3 ). Based on the possible precipitation of CaTiO 3 from TiFeO 3 , the electrochemical decomposition of CaTiO 3 is here examined using combination of the calciothermic reduction and the electrolysis of CaO in the same molten salt. Inhomogeneous reduction in the cathodic basket is related with buoyancy of Ca and insuf cient dehydration. By optimizing the cooling conditions, CaO content in the molten salt, and dehydration method, an industrial level of 0.42 mass%O could be achieved as powder form.

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“…CaTi 2 O 4 crystallizes in the orthorhombic space group Bbmm: a = 0⋅9718 nm, b = 0⋅9960 nm and c = 0⋅3140 nm with four formula units per unit cell (Rogge et al 1998). The structure is built up from edge-sharing chains of TiO 6 octahedra that condense to form one-dimensional tunnels in which the calcium atoms are located.…”

Section: Introductionmentioning

confidence: 99%

“…Single crystals of the ternary oxide, CaTi 2 O 4 , containing trivalent titanium ions were grown by Rogge et al (1998) by reduction of CaTiO 3 with Ti metal powder in a CaCl 2 flux under nitrogen at 1273 K. The structure of CaTi 2 O 4 is pseudo-brookite-type. CaTi 2 O 4 crystallizes in the orthorhombic space group Bbmm: a = 0⋅9718 nm, b = 0⋅9960 nm and c = 0⋅3140 nm with four formula units per unit cell (Rogge et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Phase diagram of the system Ca-Ti-O at 1200 K

Jacob

Gupta

2009

Bull Mater Sci

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Phase relations in the system Ca-Ti-O have been established by equilibration of several samples at 1200 K for prolonged periods and identification of phases in quenched samples by optical and scanning electron microscopy, XRD and EDS. Samples representing 20 compositions in the ternary system were analyzed. There was negligible solid solubility of Ca in the phases along the binary Ti-O, and of Ti in CaO. Four ternary oxides were identified: CaTiO 3 , Ca 4 Ti 3 O 10 and Ca 3 Ti 2 O 7 containing tetravalent titanium, and CaTi 2 O 4 containing trivalent titanium. Tie-lines link calcium titanite (CaTi 2 O 4 ) with the three calcium titanates (CaTiO 3 , Ca 4 Ti 3 O 10 and Ca 3 Ti 2 O 7 ), CaO, oxygen excess TiO 1+δ and stoichiometric TiO. Tie-lines connect CaTiO 3 with TiO 2-x , Magneli phases Ti n O 2n-1 (28 ≥ n ≥ 4), Ti 3 O 5 , Ti 2 O 3 and TiO 1+δ . CaO was found to coexist with TiO, and Ti-O solid solutions α and β. The phase diagram is useful for understanding the mechanisms and kinetics of direct calciothermic reduction of TiO 2 to metal and electrochemical reduction of TiO 2 using graphite anode and molten CaCl 2 electrolyte.

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A New Synthetic Route to Pseudo-Brookite-Type CaTi2O4

Cited by 36 publications

References 12 publications

In situ synchrotron diffraction of the electrochemical reduction pathway of TiO2

In situ synchrotron diffraction of the electrochemical reduction pathway of TiO2

Reduction of CaTiO<sub>3</sub> in Molten CaCl<sub>2</sub> - as Basic Understanding of Electrolysis

Phase diagram of the system Ca-Ti-O at 1200 K

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