The structurally based viscosity model proposed in our previous study is extended to include more components, e.g. SiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O and K2O. A simple method is proposed to calculate the numbers of different types of oxygen ions classified by the different cations they bonded with, which is used to characterize the influence of composition on viscosity. When dealing with the aluminosilicate melts containing several basic oxides, the priority order is established for different cations for charge compensating Al3+ ions, according to the coulombic force between cation and oxygen anion. It is indicated that basic oxides have two paradox influences on viscosity: basic oxide with a higher basicity decreases viscosity more greatly by forming weaker non-bridging oxygen bond; while it increases viscosity more greatly by forming stronger bridging oxygen bond in tetrahedron after charge compensating Al3+ ion. The present model can extrapolate its application range to the system without SiO2. Furthermore, it could also give a satisfy interpretation to the abnormal phenomenon that viscosity increases when adding K2O to CaO-Al2O3-SiO2 melt within a certain composition range

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High quality ferrovanadium nitride was prepared successfully by carbothermal reduction nitridation process by using V 2 O 5 and Fe as the raw materials. The effects of reaction temperature and C/O molar ratio (content of O is defined as the oxygen in V 2 O 5) on the quality of ferrovanadium nitride were investigated in detail. It was demonstrated that C/O molar ratio had a great influence on the residue carbon, as well as the nitrogen content in the final products. It was found that the nitrogen content of the final product achieved 11.52% when the C/O molar ratio was 90% of the stoichiometric value. However, the nitrogen contents of the final products decreased with the further increase of C/O molar ratio. For the temperature higher than 1773 K, Fe became liquid phase and surrounded the solid V(C, N, O) particles tightly. The formation of liquid Fe was beneficial for the further removal of oxygen atoms left in the V(C, N, O) lattice, since it provided a liquid tunnel for carbon diffusion which greatly enhanced the reaction kinetics. From the results of X-ray diffraction (XRD) and thermodynamic calculations, phase evolution sequence of V 2 O 5 can be obtained as: V 2 O 5 →VO 2 →V 2 O 3 →V(C, N, O). Moreover, the kinetic process from V 2 O 3 to VN was studied and the results shown that the reaction rate can be described by Jander diffusion model with the extracted activation energy of 188.173 kJ/mol.

The present study is aim ed to distinguish the different influences o f CaO and MgO, as w ell as A 1,03 and SiO , on viscosity o f C a O -M gO -A ip.-SiO . melts. It is fo u n d that fo r melt without A l,0 3, viscosity increases m onotonously as CaO is gradually replaced by MgO. The addition o f A 1,03 leads to a complex variation o f viscosity. In different composition ranges, viscosity may exhibit different variation tendencies as changing the relative contents o f CaO and MgO while keeping contents o f other components constant. It is also fo u n d that when replacing SiO , by equivalent mole o f A l,0 3, (i) in CaO-A 1,0,-SiO, system, viscosity increases when A l,0 } content is sm all relative to CaO content (there are enough Car' ions to charge compensate A T 4 ions), but decreases when CaO content is inadequate fo r charge compensation; (ii) in MgO-Al,OsSiO , system, viscosity always decreases as substituting A l,0 3fo r SiO,. The reason fo r this difference fo r two systems may be resulted from the weak charge compensation ability o f Mg1 2* ion fo r Al3' ion relative to Ca2* ion. A ll the viscosity variations can be interpreted well by our new proposed viscosity model. Keywords: Viscosity; C aO -M gO -A l,03-S iO B r id g in g oxygen; Non-bridging oxygen