Approaches to improve alumina extraction based on the phase transformation mechanism of recovering alkali and extracting alumina by the calcification-carbonization method

2019 ◽  
Vol 189 ◽  
pp. 105123 ◽  
Author(s):  
Guanting Liu ◽  
Yan Liu ◽  
Ting'’an Zhang
2018 ◽  
Vol 283 ◽  
pp. 23-36 ◽  
Author(s):  
Yothin Chimupala ◽  
Rik Drummond-Brydson

Titanium dioxide (B phase) with 1-D structures was successfully fabricated via a hydrothermal method with a subsequent ion-exchange process and calcination. P25, titanium isopropoxide (TTIP), rutile and also anatase were used as Ti precursors in the alkali hydrothermal system. TTIP promoted an elongation of nanorod morphology whereas the other precursors produced short nanorod structures. The different types of titanium precursors did not have any influence on the phase transformation during the fabrication process. Na2Ti6O13 was the primary intermediate product after washing the hydrothermal sample. H2Ti3O7 was the secondary intermediate phase obtained following proton-exchange of Na2Ti6O13 in HNO3 solution. Finally, the TiO2(B) phase was the product of calcination of the secondary intermediate product at 400°C for 5 hr. A phase transformation mechanism is presented based on an investigation of products at each of the steps. The effects of the synthesis conditions on tailoring of the crystal morphology are discussed. The growth direction of the TiO2(B) nanorods was investigated by HR-TEM and SADP. Finally, the metastable phase of TiO2(B) was shown to be transformed to anatase during thermal treatment at temperatures higher than 400°C.


2019 ◽  
Vol 151 ◽  
pp. 252-259 ◽  
Author(s):  
Ling Tang ◽  
Jingjing Liang ◽  
Chuanyong Cui ◽  
Jinguo Li ◽  
Yizhou Zhou ◽  
...  

2020 ◽  
Vol 196 ◽  
pp. 105771 ◽  
Author(s):  
A.B. ElDeeb ◽  
V.N. Brichkin ◽  
Martin Bertau ◽  
Yu A. Savinova ◽  
R.V. Kurtenkov

2011 ◽  
Vol 295-297 ◽  
pp. 515-519 ◽  
Author(s):  
Qi Wei Chen ◽  
Guo Hui Zhu ◽  
Shu Min Cao ◽  
Ai Min Zhao

A novel processing of quick spheroidizing annealing based on DET(divorced eutectoid transformation) mechanism has been presented in this paper. Spheroidized carbide microstructure could be achieved directly by austenite through phase transformation during cooling processing, which is different from the conventional spheroidization annealing where carbide was spheroidized by carbide lamellar gradually resolved and coarsened.The novel processing of spheroidizing annealing presented here will decrease the annealing time from 10-16 hours in conventional processing to around 2-3 hours, which could save about 50% of the energy consumption, comparing to the conventional annealing processing.


2006 ◽  
Vol 979 ◽  
Author(s):  
Xiao Ma ◽  
R.C. Pond

AbstractOur current understanding of martensitic transformations has been based on the Phenomenological Theory of Martensite Crystallography developed in the 1950s. Recently, a Topological Model of martensitic transformations has been presented wherein the habit plane is a semi-coherent structure, and the transformation mechanism is shown explicitly to be diffusionless. This approach is used here to model phase transformation crystallography of lath martensite in ferrous alloys. A range of network geometries is predicted corresponding to orientation relationships varying from Nishiyama-Wasserman to Kurdjumov-Sachs. Experimental observations from the literature of the dislocation and disconnection arrays, habit plane and orientation relationship are in good agreement with the model.


2020 ◽  
Vol 169 ◽  
pp. 110640
Author(s):  
Ehsan Farabi ◽  
Vahid Tari ◽  
Peter D. Hodgson ◽  
Gregory S. Rohrer ◽  
Hossein Beladi

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