scholarly journals Removal of Mg and MgO By-Products Through Magnesiothermic Reduction of Ti Powder in Self-Propagating High-Temperature Synthesis

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 169 ◽  
Author(s):  
Sang Hoon Choi ◽  
Jae Jin Sim ◽  
Jae Hong Lim ◽  
Dong-Wook Kim ◽  
Soong-Keun Hyun ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
High Temperature ◽  
Hydrochloric Acid ◽  
Acid Leaching ◽  
Temperature Synthesis ◽  
Vacuum Oven ◽  
High Temperature Synthesis ◽  
Leaching Condition ◽  
Ti Powder ◽  
By Products

Commercial production of titanium involves chlorination using chlorine gas that can be converted to hydrochloric acid by atmospheric moisture and is hazardous to human health. In the titanium production process, self-propagating high-temperature synthesis is one of the process to directly reduce titanium dioxide. In this work, titanium powder was prepared by self-propagating high-temperature synthesis using titanium dioxide as the starting material and magnesium powder as a reducing agent. After the reaction, magnesium and magnesium oxide by-products were then removed by acid leaching under different leaching conditions, leaving behind pure Ti. During each leaching condition, the temperature of the leaching solution was carefully monitored. After leaching, the recovered titanium in the form of a powder was collected, washed with water and dried in a vacuum oven. Detailed compositional, structural, and morphological analyses were performed to determine the presence of residual reaction by-products. It was found that leaching in 0.4 M hydrochloric acid followed by second leaching in 7.5 M hydrochloric acid is the optimum leaching condition. Furthermore, it was also noticed that total volume of solution in 0.4 M hydrochloric acid leaching condition is advantageous to maintain uniform temperature during the process.

Production of Zirconium Diboride Powder by Self Propagating High Temperature Synthesis

2010 ◽  
Vol 63 ◽  
pp. 251-256 ◽  
Author(s):  
Burcu Akkas ◽  
Murat Alkan ◽  
Bora Derin ◽  
Yücel Onüralp
Keyword(s):  
High Temperature ◽  
Acid Leaching ◽  
Zirconium Diboride ◽  
The Self ◽  
Selective Leaching ◽  
Temperature Synthesis ◽  
Technical Grade ◽  
Zro2 Powder ◽  
High Temperature Synthesis

In this study, the self-propagating high-temperature synthesis (SHS) and following acid leaching techniques were carried out to produce zirconium diboride (ZrB2) powder. In the SHS experiments, technical grade ZrO2 powder, and different amounts of B2O3 and Mg powders were used. The SHS products were obtained in the form of black, spongy solid. In the leaching step, the effect of different acid concentrations on selective leaching was investigated by using optimum SHS product to eliminate the impurities such as MgO, Mg3B2O6 and Mg2B2O5. The products obtained were characterized by using XRD, ICP and SEM techniques.

Alumina Whiskers Formation during Self-Propagation High-Temperature Synthesis

2007 ◽  
Vol 280-283 ◽  
pp. 1021-1022 ◽  
Author(s):  
Ling Zhen Zhang ◽  
Chun Chao Zhang
Keyword(s):  
Titanium Dioxide ◽  
High Temperature ◽  
Growth Mechanism ◽  
Raw Materials ◽  
Combustion Process ◽  
The Self ◽  
Combustion Mode ◽  
Temperature Synthesis ◽  
Aluminum Powders ◽  
High Temperature Synthesis

In this paper, the SHS process was accomplished using titanium dioxide and aluminum powders as raw materials. It was found that the combustion process exhibited the self-spiral combustion mode and alumina whisker had formed. The morphology, microstructure and growth mechanism of alumina whisker were investigated.

Self-Propagating High-Temperature Synthesis of Simulated 90SrO-Contained Radioactive Graphite in N2 Atmosphere

2014 ◽  
Vol 525 ◽  
pp. 45-52 ◽  
Author(s):  
Xi Rui Lu ◽  
Si Jin Su ◽  
Meng Jun Chen
Keyword(s):  
Titanium Dioxide ◽  
High Temperature ◽  
Titanium Carbide ◽  
Exothermic Reaction ◽  
The Self ◽  
Cubic Phase ◽  
Temperature Synthesis ◽  
Radioactive Graphite ◽  
Waste Forms ◽  
High Temperature Synthesis

In order to evaluate the performance of the self-propagating high-temperature synthesis (SHS) to treat 90SrO-contained radioactive graphite in N2 atmosphere, waste forms were prepared with the self-developed SHS reactor according to the waste forms formulation designed with a solid-soluted content of 010 wt% (calibrated in mass, hereinafter the same). The waste forms were made with the exothermic reaction (3C + 4Al + 3TiO2 = 2Al2O3 + 3TiC + Q), where, 88SrO (a stable Sr isotope)-containing 88SrO was used to simulate 90SrO. And the raw materials for the waste forms were the powdery materials of graphite (C), aluminum (Al) and titanium dioxide (TiO2). Then, X-ray diffractometer (XRD) and scanning electron microscope (SEM) were used to test and analyze the phase composition and morphology of the prepared waste forms. According to the results in dealing with the treatment with the given exothermic reaction of the 90SrOcontaining radioactive graphite in N2 atmosphere, the SrO solid solubility could be up to 8 wt%. Besides, with a SrO content of 0~2 wt%, the major composition of the waste forms was including: alumina (Al2O3) in diamond scheme, titanium carbide (TiC) in cubic phase, graphite (C), anatase titanium dioxide (TiO2) and aluminum nitride (AlN) in cubic phase. Comparatively, with a SrO content of 3~8 wt%%, the major composition of the waste forms was including: alumina (Al2O3) in diamond scheme, titanium carbide (TiC) in cubic phase, graphite (C), anatase titanium dioxide (TiO2), aluminum nitride (AlN) in cubic phase and rhomboid aluminum titanate (Al2TiO5). Furthermore, diffractive peaks of unidentified phase occurred at 2θ = 7.7°, 15.6°, 19.8° and 24.1° position, whose intensities were increased with the increasing additional SrO content. The grain sizes of the prepared waste forms are mainly within 515μm, majorly exist in pieces.

Hardening of metal surface via self-propagating high-temperature synthesis in thin films

2007 ◽  
Vol 43 (4) ◽  
pp. 239-242
Author(s):  
S. Kh. Suleimanov ◽  
O. A. Dudko ◽  
V. G. Dyskin ◽  
Z. S. Settarova ◽  
M. U. Dzhanklych
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Metal Surface ◽  
Temperature Synthesis ◽  
High Temperature Synthesis
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