Effect of heat treatment method on microstructure of tailings glass ceramics

Abstract

A Cao-Mgo-Al₂O₃-SiO₂ quaternary system was established with the main crystal phase design based on Diopside, and the effect of once-through sintering heat treatment on microstructure of iron tailings glass ceramics was studied by using DTA, SEM along with measurement of microhardness and volume density. The experimental results show that, when the total amount of FeO and Fe₂O₃ exceeds 10wt%, a large number of fine nuclei are produced in the annealing process, and the phenomenon of nucleus resorption happens during the process of nucleation heat treatment, which is unfavorable for preparing iron tailings glass ceramics through once-through sintering method. When the annealing temperature from 1250 °C to 830 °C, setting crystallization time for 4h, without heat treatment, crystals are well grown with arrangement and interlocking in glass phase. At 830 °C the crystals are well developed, well distributed and of good size; with crystallization time of 4 h the crystals with radial shape have high content and regular arrangement.

Keywords

one-time sintering / heat treatment / glass ceramics / microstructure

References

[1] Cheng J., Li H., . Glass Ceramics[M], 2006. Beijing: Chemical Industry Press.

[2] Macmillan P. W. Glass Ceramics[M], 1998. Beijing: China Building Industry Press.

[3] Cheng T. W., Cheng Y. S. On formation of Cao-Al₂O₃-SiO₂ Glass-ceramics by Vitrification of in Cinerator Fly Ash [J]. Chenosphere, 2003, 51: 817-824.

[4] Wang Wenju. Effect of Cooling Process on Strength and Thermal Expansion Property of Cao-Al₂O₃-SiO₂ Glass-ceramics[J]. Journal of Tsinghua University, 2006, (2):6–9

[5] Yu Jianxin, Song kaixin, Liu Xuli. Investigation of Niobium Tantalum Tailings Heat Treatment by Orthogonal Experiment Method[J]. Bulletin of the Chinese SERAmIc Society, 2003, (6): 30–33

[6] Xing J., Song s., Liu w., . Study on Controlled Crystallization of Mgo-Al₂O₃-SiO₂ Glass Ceramics[J]. Journal Of Northeatern University, 2000, 21(5): 558-561.

[7] Shi P., Wang y., Zhang d., . Effect of Crystallization Process on Glass Ceramics Microstructure[J]. Journal of Northeatern University, 2007, 28(5): 668-671.

[8] Tian Y. Development and preparation of Cao-Mgo-Al₂O₃-SiO₂ Glass Ceramics by Using Iron Tailings[J]. Journal of Beijing University of Technology, 2002, 28(3): 369-373.