Structure, Growth Process, and Growth Mechanism of Perovskite in High-Titanium-Bearing Blast Furnace Slag
- PDF / 2,029,867 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 78 Downloads / 164 Views
INTRODUCTION
THE Panzhihua–Xichang area has abundant vanadium-titanium magnetite ores, which are the source of more than 90 pct titanium resource in China. Currently, after mineral separation and a blast furnace smelting process, more than 50 pct titanium in raw ores finally gathers in the blast furnace (BF) slag, making the titanium content in terms of TiO2 in slag up to 23 pct (Figure 1).[1] The high titanium content has a big influence on the use of the slag, especially the high melting point phase, the rich-titanium phase—perovskite (CaTiO3) affects the slag property and titanium extraction.[2,3] On the one hand, CaO mostly exists as perovskite with TiO2 in high-titanium-bearing BF slag, which in turn makes the slag unsuitable to be used as cement like the normal BF slag. On the other hand, the extraction of valuable secondary titanium resource from the slag always faces challenges. Gathering titanium into LU LIU and YUZHOU XU, Graduate Students, MEILONG HU, Associate Professor, CHENGUANG BAI, Professor, are with the College of Materials Science and Engineering, Chongqing University, Chongqing, 400044 P.R. China. YUNHUA GAN, Associate Professor, is with the School of Electric Power, South China University of Technology, Guangzhou 510640, P.R. China. Contact e-mails: hml@ cqu.edu.cn; [email protected] Manuscript submitted September 3, 2014. Article published online May 27, 2015. METALLURGICAL AND MATERIALS TRANSACTIONS B
perovskite was once considered to be a promising technology.[2] However, the perovskite yield is rather low because of the adverse effects of the fine and uneven perovskite grains on the mineral separation.[4] Therefore, it is necessary to study the crystallization of perovskite in high-titanium-bearing blast furnace slag. A confocal scanning laser microscope (CSLM) has been used successfully to study the high-temperature behavior of slag system. Jung and Sohn[5] observed the crystallization behavior of a calcium-aluminate system with various MgO contents, CaO/Al2O3 ratios, and cooling rates using a CSLM. The results indicated a change in primary phase and crystal morphology from dendrites to faceted crystals to columnar crystals in the composition range. Jung and Sohn[6] also investigated the effect of FeO concentration on the crystallization of high-temperature CaO-Al2O3-MgO-FeO melts with a CSLM. Continuous-cooling-transformation (CCT) and time–temperature–transformation (TTT) diagrams were plotted for melts, and the morphology of the primary crystals formed was determined. Orrling et al.[7] studied the role of alumina particle in SiO2-CaO-Al2O3-MgO slag by CSLM. Semykina et al.[8] observed the crystal growth of liquid FeO-CaO-SiO2 slag during oxidation by using the CSLM. Sridhar and Cramb[9] described the kinetics of Al2O3 dissolution in the CaO-MgO-SiO2Al2O3 slag with a CSLM. The crystallization of perovskite in high-titaniumbearing blast furnace slag during continuous cooling has VOLUME 46B, AUGUST 2015—1751
Fig. 1—The flow direction of titanium in blast furnace process.
been studied in situ b
Data Loading...
