scholarly journals Effect of sulfur and sodium sulfate on phase transformation and microstructure on carbothermic reduction of Indonesian ilmenite

2020 ◽  
Vol 833 ◽  
pp. 012092
Author(s):  
Agung Setiawan ◽  
Sri Harjanto
Keyword(s):  
Phase Transformation ◽  
Sodium Sulfate ◽  
Carbothermic Reduction

scholarly journals Carbothermic Reduction and Nitridation Mechanism of Vanadium-Bearing Titanomagnetite Concentrate

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 730
Author(s):  
Wen Yu ◽  
Xiaojin Wen ◽  
Wei Liu ◽  
Jiangan Chen
Keyword(s):  
Phase Transformation ◽  
Carbothermic Reduction ◽  
Titanium Oxides ◽  
Distribution Characteristic ◽  
Reaction Behavior ◽  
Microstructure Transformation ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Roasting Process ◽  
Rate Limiting

In this study, the carbothermic reduction and nitridation mechanism of vanadium-bearing titanomagnetite concentrate are investigated in terms of phase transformation, microstructure transformation, and thermodynamic analyses. The differences in the reaction behavior of titanomagnetite and ilmenite in vanadium-bearing titanomagnetite concentrate, as well as the distribution characteristic of V in the roasted products, are emphatically studied. It is observed that the reaction sequences of titanomagnetite and ilmenite transformations into nitride are as follows: Fe3−xTixO4→Fe2TiO4→FeTiO3→M3O5→(Ti, V)(N, C); FeTiO3→M3O5→Ti(N, C). The reduction of M3O5 to TiN is the rate-limiting step of the entire reaction, and metal iron is an important medium for transferring C for the reduction of M3O5. Titanomagnetite is faster to convert into nitride than ilmenite is, and the reasons for this are discussed in detail. During the entire roasting process, V mainly coexists with Ti and seems to facilitate the conversion of titanium oxides into (Ti, V)(N, C).

Carbothermic reduction of ilmenite concentrate in semi-molten state by adding sodium sulfate

2018 ◽  
Vol 340 ◽  
pp. 354-361 ◽  
Author(s):  
Wei Lv ◽  
Chenguang Bai ◽  
Xuewei Lv ◽  
Kai Hu ◽  
Xueming Lv ◽  
...  
Keyword(s):  
Sodium Sulfate ◽  
Carbothermic Reduction ◽  
Molten State ◽  
Ilmenite Concentrate

scholarly journals Phase Transformation of Alumina, Silica and Iron Oxide during Carbothermic Reduction of Fly Ash for Ceramics Production

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1165
Author(s):  
Qingchun Yu ◽  
Yong Deng ◽  
Yuebin Feng ◽  
Ziyong Li
Keyword(s):  
Phase Transformation ◽  
Fly Ash ◽  
Carbothermic Reduction ◽  
Energy Dispersive Spectrometry ◽  
Intermediate Compound ◽  
Added Value ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reduced Products ◽  
Electronic Microscope

Fly ash is a by-product from burning of coal. Utilization of fly ash by carbothermic reduction is an effective way to recover aluminum, silicon, and iron to enhance product-added value. This work is focused on the phase transformation of Al2O3, SiO2 and Fe2O3 during carbothermic reduction of fly ash in air. A comparative analysis of carbothermic reduction of fly ash in air and in nitrogen was made. Thermodynamics analysis was performed to illustrate the possible reactions for residue and condensate. X-ray diffraction (XRD), scanning electronic microscope (SEM), and energy dispersive spectrometry (EDS) were employed to characterize the phase composition, surface morphology, and microstructure of the reduced products. Results show that Fe3Si and Fe2Si appear sequentially with increasing of temperature. Al5O6N is an intermediate compound. Residue of Al9FeSi3, Al, and Si, and condensate of SiC, AlN and C are obtained. β-SiAlON was not found in the residue. Nitrogen is involved in the reduction of Al2O3 but not in the reduction of SiO2 and Fe2O3. Carbothermic reduction of fly ash in air did not behave the same as fly ash in nitrogen.

Phase Transformation In Ti-6al-4v Alloys

1972 ◽  
Vol 30 ◽  
pp. 584-585
Author(s):  
Shiro Fujishiro
Keyword(s):  
Phase Transformation ◽  
Grain Boundary ◽  
Cryogenic Temperature ◽  
Β Phase ◽  
Heat Treated ◽  
Mixed Microstructure ◽  
Ductile Behavior

The Ti-6 wt.% Al-4 wt.% V commercial alloys have exhibited an improved formability at cryogenic temperature when the alloys were heat-treated prior to the tests. The author was interested in further investigating this unusual ductile behavior which may be associated with the strain-induced transformation or twinning of the a phase, enhanced at lower temperatures. The starting materials, supplied by RMI Co., Niles, Ohio were rolled mill products in the form of 40 mil sheets. The microstructure of the as-received materials contained mainly ellipsoidal α grains measuring between 1 and 5μ. The β phase formed an undefined grain boundary around the a grains. The specimens were homogenized at 1050°C for one hour, followed by aging at 500°C for two hours, and then quenched in water to produce the α/β mixed microstructure.

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