Effects of Magnesite Concentrate Powder Additions on Phase Composition and Microstructure of Fused Magnesia

doi:10.19691/j.cnki.1004-4493.2026.01.007

China's Refractories ›› 2026, Vol. 35 ›› Issue (1): 44-50.DOI: 10.19691/j.cnki.1004-4493.2026.01.007

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Effects of Magnesite Concentrate Powder Additions on Phase Composition and Microstructure of Fused Magnesia

SUI Jipeng¹, FENG Yu¹, YOU Jiegang^1,*, ZHAO Xin¹, FENG Dong¹, ZHANG Xiaofang¹, HOU Qingdong¹, LUO Xudong²

1 School of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan 114051, China;
2 Liaoning Institute of Science and Technology, Benxi 117004, China

Online:2026-03-15 Published:2026-03-16
Contact: ^*e-mail: youjiegang@163.com
About author:Sui Jipeng, born in 2000, received a bachelor’s degree in inorganic non-metallic materials engineering from University of Science and Technology Liaoning in 2023. At present, he is a master’s degree candidate in material science and engineering in the same university.

Abstract

Abstract: Adding magnesite flotation concentrate powder in the production of fused magnesia has become an important method for reducing costs and improving the yield. However, the extensive use of concentrate powder also reduces the quality of fused magnesia raw materials, which is a major cause of the reduced slag corrosion resistance and service life of magnesia-carbon refractories. The effects of concentrate powder additions (0, 30%, 60%, and 90%, by mass) on the chemical composition, phase composition, microstructure, bulk density, and apparent porosity of the produced 97-grade fused magnesia were investigated. The results show that as the concentrate powder addition increases, the bulk density first increases and then decreases, while the apparent porosity first decreases and then increases. The crystal size of the fused magnesia increases, and the pores at the grain boundaries become larger. The CaO/SiO₂ molar ratio (C/S ratio) in the fused magnesia increases from 1.17 to 4.17. The bonding phases between the fused magnesia grains change from low-melting-point phases such as CMS (CaMgSiO₄) and C₃MS₂ (3CaO·MgO· 2SiO₂) to high-melting-point phases like C₂S (2CaO·SiO₂), C₃S (3CaO·SiO₂), and CaO, which is beneficial for improving the high-temperature performance of the fused magnesia. However, during production, the volume effects resulting from the polymorphic transformation of dicalcium silicate (C₂S) and the low-temperature decomposition of tricalcium silicate (C₃S) create significant voids around the fused magnesia grains. These voids can provide pathways for slag corrosion in subsequent magnesia-carbon products, which is likely the primary reason for the decline in the slag corrosion resistance and service life of carbon-containing refractories made from this type of fused magnesia.

Key words: magnesite concentrate powder, fused magnesia, phase composition, microstructure

SUI Jipeng, FENG Yu, YOU Jiegang, ZHAO Xin, FENG Dong, ZHANG Xiaofang, HOU Qingdong, LUO Xudong. Effects of Magnesite Concentrate Powder Additions on Phase Composition and Microstructure of Fused Magnesia[J]. China's Refractories, 2026, 35(1): 44-50.

References

[1] Li Yanjing, Sun Jialin, Li Yong, Kang Jian, Ma Shulong, Ma Fei, Gao Changhe, Zhang Jili, Zhang Haibo.Effect of flotation magnesia particles and Al₂O₃ fines on properties of periclase-spinel bricks. Refractories (in Chinese), 2022, 56(1): 6-9.
[2] She Yiming, Wang Peng, You Jiegang, Si Chaowei, Zheng Huaguo.Effect of four kinds of fused magnesia particles on properties of magnesia-carbon bricks. Refractories (in Chinese), 2022, 56(3): 241-246.
[3] Zhao Haixin.Current status of liaoning’s magnesite resources and development suggestions. Refractories (in Chinese), 2009, 43(4): 291-293.
[4] You Jiegang, Zhao Xin, Qian Guohua, Zhang Xiaofang, Zhang Guodong, Ma Beiyue.Development status of fused magnesia in southern Liaoning. Refractories (in Chinese), 2024, 58(4): 357-361.
[5] Xin Zhao, Jiegang You, Jingjing Yue, Xudong Luo, Beiyue Ma.Microstructure and mechanistic analysis of high-calcium fused magnesia molten heap. Journal of the Australian Ceramic Society, 2024, 60: 1529-1539.
[6] Liu Runjing, Xu Kai, Zhang Tengteng.Analysis of the production status of light-burned magnesia, dead-burned magnesia, and fused magnesia in China. Proceedings of Magnesium Compound Industry Annual Conference and Technical Equipment Exchange Meeting (in Chinese), Wuxi, China, 2014: 45-52.
[7] Zhen Li, Dianli Qu, Jijia Li, Xudong Luo, Yuxiang Guo, Chunxin Wang, Yuan Li.Effect of different electrofusion processes on microstructure of fused magnesia. Refractories and Industrial Ceramics, 2022, 62(5): 541-547.
[8] Wang Cong, Zheng Lianying, Wang Yingying, Su Xin, Bai Rongan.Analysis and comparison of magnesia’s microstructure from different processes. Refractories & Lime (in Chinese), 2023, 48(6): 40-44.
[9] Wang Lili, Qin Ying, Zhang Di, Yang Haifeng, Zhang Ronghui.Study on structure and properties of super large crystalline fused magnesia. Proceedings of 2023 National Symposium on Refractory Raw Materials (in Chinese), Zibo, China, 2023: 8.
[10] Luan Jian.Study on microstructure and control of magnesia. Proceedings of the 2^nd Academic Conference on High Temperature Materials, Zhengzhou, China, 2023: 10-15.
[11] Wang Weibang.Technology of Refractory Materials(in Chinese). Beijing: Metallurgical Industry Press, 2007.
[12] Liugang Chen, Annelies Malfliet, Peter Tom Jones, Bart Blanpain, Muxing Guo.Comparison of the chemical corrosion resistance of magnesia-based refractories by stainless steelmaking slags under vacuum conditions. Ceramics International, 2016, 42(1): 743-751.
[13] Zhang Genting, Liu Zhao, Zhou Zhenni, Lyu Baolei, Yu Yanlong.Effect of CaO/SiO₂ in high purity fused magnesia on production and properties of fused magnesia bricks. Proceedings of 2021 National Symposium on Refractory Raw Materials (in Chinese), Chongqing, China, 2021: 9.
[14] Zhao Xin, Yue Jingjing, She Yiming, You Jiegang.Study on the effect of aluminum powder on 95-electrofused magnesia in nitriding atmosphere. Proceedings of 2023 National Symposium on Refractory Raw Materials (in Chinese), Zibo, China, 2023: 8.
[15] Zhu Yening, Xi Zijian, Su Yuqing, Yu Baisong, Tu Junbo, Wei Juncong, Miao Zheng, Wang Yilong.Effect of magnesia grade on microstructure and composition of magnesia carbon bricks. Industrial Heating(in Chinese). 2023, 52(3): 21-25.
[16] Yang Shu, Liu Baikuan, Tian Xiaoli, Li Zhixun, Feng Runtang, Guo Jie.Preparation and micro-morphology of high purity fused magnesia in Sichuan-Tibet. Bulletin of the Chinese Ceramic Society (in Chinese), 2019, 38(9): 2777-2781, 2787.
[17] Xiang Xie, Guimi Lu, Wei Du, Yinxiong Wang.Effect of TiO₂ on melting and crystallization mechanism of fused magnesia. Asian Journal of Chemistry, 2015, 27(5): 1823-1827.
[18] Ma Beiyue, Mu Xin, Gao Zhi, Liu Yuyang, Ma Pengcheng, Ren Xinming.Research progress on thermal shock resistance of low-carbon magnesia carbon refractories. Refractories (in Chinese), 2021, 55(2): 174-177, 181.
[19] Xing Yidan, Liu Xingli, Huang Liang, Zhang Haijun.Research progress on slag resistance of different basic refractory materials. Refractories (in Chinese), 2024, 58(6): 1-13.
[20] Qingdong Hou, Xudong Luo, Zhipenng Xie, Di An, Xiaofang Zhang, Zijun Peng.Effect of magnesia-alumina spinel precursor sol on the sintering property of fused magnesia refractory. Ceramics International, 2019, 45(3): 3459-3464.
[21] Chen Shunlin, Tian Rongzhang.Phase diagram analysis and application(in Chinese). Metallurgical Industry Press, 2007: 116-119.

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