High-temperature heat capacity and thermal expansion of the MnTa2O6

Recycling of metallic values from discarded tantalum capacitors

“…Hence, pre-concentration of the Ta values by selective separation of the sintered core was not achieved. The XRD analysis (Figure 4(a)) revealed the formation of brittle Ta-oxide (Ta 2 O 5 ) and a complex phase of Mn-Ta-O (MnTa 2 O 6 ) which agreed with previous findings (Mineta and Okabe 2005; Gulyaeva et al 2020). The complex phase formations are undesirable for individual metal recoveries and hinder the downstream processing separation.…”

Pressure-Induced Phase Transition in Mn(Ta,Nb)2O6: An Experimental Investigation and First-Principle Study

“…The families of oxide compounds with the general formula AB 2 O 6 (A-Fe, Mn, Mg, Zn, Ca, Co, Ni; B-Ta, Nb, V, Pb) have attracted much interest because of their important use in technological applications. − The high permittivity and low dielectric loss at microwave frequencies make these materials suitable for use as resonators in the fields of satellite communications, supercapacitors in electric cars, ceramics in microwave technology, and many other electric devices. − The AB 2 O 6 compounds are also used as important intermediates for the synthesis of perovskite structure related materials . Among AB 2 O 6 compounds, (Mn,Fe)­(Nb,Ta) 2 O 6 with A and B sites mainly occupied by Mn 2+ or Fe 2+ and Ta 5+ or Nb 5+ , respectively, deserves special attention due to its potential applications …”

“…In a stable state, manganotantalite shows a columbite-type structure that crystallizes in orthorhombic symmetry with space group of Pbcn , in which edge-sharing [AO 6 ] and [BO 6 ] octahedra chains run parallel along the c -axis. , There are other four synthetic polymorphs of MnTa 2 O 6 formed at different temperatures and pressures, which have trirutile, wolframite, wodginite, and modulated α-PbO 2 structures, respectively . Previous studies have focused on the properties of (Mn,Fe)­(Nb,Ta) 2 O 6 compounds at ambient and high-temperature conditions. − It is reported that the changes in thermal expansion coefficients of unit cell parameters revealed anisotropic expansion behaviors of FeNb 2 O 6 , FeTa 2 O 6 , and MnTa 2 O 6 with temperature. ,, The thermodynamic research shows that FeNb 2 O 6 undergoes a phase transition from orthorhombic to tetragonal structure at 1630 K …”

“…5 Among AB 2 O 6 compounds, (Mn,Fe)(Nb,Ta) 2 O 6 with A and B sites mainly occupied by Mn 2+ or Fe 2+ and Ta 5+ or Nb 5+ , respectively, deserves special attention due to its potential applications. 10 In the natural state, (Mn,Fe)(Nb,Ta) 2 O 6 compounds are found in granitic pegmatites or highly differentiated granite bodies enriched in volatile elements. 11 The (Mn,Fe)-(Nb,Ta) 2 O 6 family of compounds encompass two different solid solution series, named tantalite-columbite with orthorhombic structure and tapiolite-mossite with tetragonal structure, the compositional fields were presented in literature, of which the manganotantalite Mn(Ta,Nb) 2 O 6 belongs to tantalite−columbite series.…”

“…16−18 It is reported that the changes in thermal expansion coefficients of unit cell parameters revealed anisotropic expansion behaviors of FeNb 2 O 6 , FeTa 2 O 6 , and MnTa 2 O 6 with temperature. 10,19,20 The thermodynamic research shows that FeNb 2 O 6 undergoes a phase transition from orthorhombic to tetragonal structure at 1630 K. 18 High pressure has been employed as an efficient tool for improving the understanding of the properties of functional materials. For instance, structural transition and lattice distortions induced by pressure in α-Co[N(CN) 2 ] 2 alter the superexchange interactions and correlate with the ferromagnetic-antiferromagnetic crossover.…”