硅酸盐学报

H₂/CO条件下氧化钛-氧化铁对莫来石质耐火材料稳定性的影响

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柯文丽 ¹ , 廖宁 ¹ , 颉付博 ¹ , 李亚伟 ¹ , 蔡国庆 ² , 秦建涛 ²

硅酸盐学报 | 碳中和与耐火材料专题—研究论文 2025,53(9): 2586-2596

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硅酸盐学报 |碳中和与耐火材料专题—研究论文 2025 , 53 (9) : 2586 -2596

H₂/CO条件下氧化钛-氧化铁对莫来石质耐火材料稳定性的影响

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柯文丽¹, 廖宁¹, 颉付博¹, 李亚伟¹, 蔡国庆², 秦建涛²

作者信息

^1．武汉科技大学，先进耐火材料全国重点实验室，武汉 430081

^2．山东耐材集团鲁耐窑业有限公司，山东淄博 255200

通讯作者:

廖宁（1988—），男，副教授。

作者简介:

柯文丽（2001—），女，硕士研究生。

Effect of Titanium Oxide/Iron Oxide on Stability of Mullite-Based Refractories Under H₂+CO Conditions

Wenli KE¹, Ning LIAO¹, Fubo XIE¹, Yawei LI¹, Guoqing CAI², Jiantao QIN²

Affiliations

^1.Wuhan University of Science and Technology, State Key Laboratory of Advanced Refractories, Wuhan 430081, China

^2.Shandong Refractories Group Lunai Kiln Refractory Co., Ltd, Zibo 255200, Shandong, China

Corresponding Author:

LIAO Ning (1988-), male, Master Candidate. E-mail: liaoning@wust.edu.cn

KE Wenli (2001-), female, Master Candidate. E-mail: 2893520757@qq.com

出版时间: 2025-09-20 doi: 10.14062/j.issn.0454-5648.20250085

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摘要

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针对氢基竖炉炉衬在强还原环境下的安全长寿服役需求，重点研究了氧化铁-氧化钛赋存形态对莫来石质耐火材料还原稳定性的影响机制。通过构建H₂/CO（体积比5：2）强还原环境，考察了不同预处理工艺对材料结构稳定性的作用规律。结果表明：不预烧的氧化钛-氧化铁复合试样在950 ℃处理后呈现显著结构劣化，表现为基质中形成大量微米级孔隙及骨料-基质界面结合弱化，导致耐压强度峰值仅38.6 MPa，强度衰减率高达17.3%~26.5%。预烧处理的氧化钛-氧化铁复合试样在1050 ℃还原后保持良好结构完整性，当TiO₂与Fe₂O₃质量比>2.0时，材料耐压强度最低值仍达71.9 MPa，显微结构分析显示试样未出现明显裂隙，强度衰减率控制在10%以内。作用机理在于：不预烧复合物引入试样中形成的Al₂TiO₅与Fe₂O₃复合相难以有效抑制Fe₂O₃还原反应，导致金属铁析出和体积收缩；而预烧形成的Fe₂TiO₅在还原过程中优先转化为亚铁化合物FeTiO₃相，通过构建Fe—O—Ti协同稳定结构，显著提升材料抗H₂/CO还原侵蚀能力，为开发高稳定性氢基竖炉耐火材料提供了理论依据。

关键词

氢基竖炉 / 氢气/一氧化碳气氛 / 氧化钛-氧化铁复合氧化物 / 莫来石质耐火材料 / 还原稳定性

Abstract

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Introduction

The global imperative to reduce carbon emissions has catalyzed the development of hydrogen-based metallurgical technologies, with hydrogen shaft furnaces emerging as a promising low-carbon alternative for ironmaking. These reactors demand refractory linings with an exceptional stability to withstand synergistic thermal, chemical, and mechanical stresses when operating under extreme reducing environments (i.e., H₂/CO atmospheres at 1050 ℃, 0.5-1.0 MPa). Conventional aluminosilicate refractories, while widely used, suffer from deleterious reactions in H₂-rich atmospheres, including silica volatilization, carbon deposition via the Boudouard reaction, and structural degradation induced by iron oxide (Fe₂O₃) reduction. Recent studies highlight that co-doping Fe₂O₃ with TiO₂ can mitigate these issues, yet systematic investigations into the role of TiO₂/Fe₂O₃ phase chemistry and pretreatment strategies remain scarce. This study was to elucidate the impact of TiO₂/Fe₂O₃ composite oxides on the reduction stability of mullite-based refractories under simulated hydrogen shaft furnace conditions (i.e., H₂/CO = 5∶2). We were to investigate the phase evolution and microstructural engineering influence resistance to H₂/CO induced degradation via varying the TiO₂/Fe₂O₃ molar ratio (0.5-4.0) and employing pre-sintering treatments.

Methods

High purity electromelting mullite (Al₂O₃ >70% (in mass fraction), 3-1 mm, 1-0 mm and 200 mesh), plate corundum (Al₂O₃ >99.5%, 325 μm), α-Al₂O₃ (Al₂O₃ >99.5%, 2-5 μm), Fe₂O₃, TiO₂ powder (analytically pure), silicon powder (2 μm), and high viscosity yellow dextrin (200 μm) were used as raw materials. Fe₂O₃ and TiO₂ powder were proportioned according to the mass ratio m(TiO₂):m(Fe₂O₃) of 0.5, 1.0, 1.5, 2.0, 3.0, and 4.0, respectively, and were placed into a planetray ball mill according to a mass ratio of m(zirconium ball):m(water):m(mixed powder) of 2∶1∶1, The ball mill was operated at 300 r/min for 3 h. After milling, the slurry was taken out and put it in an oven for drying at 110 ℃ for 24 h. The ground sample was screened by a sieve with 200 mesh, thus obtaining the composite oxide of titanium oxide and iron oxide without pre-burning. The sample of φ50 mm×10 mm was prepared with the sifted powder at 100 MPa, and then heated in air at 1300 ℃ for 3 h. After cooling to room temperature, pre-burned titanium-iron oxide composite oxide was obtained.

The dextrin aqueous solution was prepared according to a ratio of m(dextrin):m(warm water) of 1∶1. The mixture was trapped at 25 ℃ for 12 h, and the cylindrical sample was shaped into φ50 mm×50 mm at 150 MPa, and dried in an oven at 110 ℃ for more than 24 h. Finally, the dried sample was heated in air to 1600 ℃ for 3 h, obtaining the titanium-iron oxide composite mullite refractory. The temperature increasing rates of this experiment were 5 ℃/min at 0-1000 ℃, 3 ℃/min at 1000-1400 ℃, and 2 ℃/min at 1400-1600 ℃, respectively.

Results and discussion

A large amount of Al₂TiO₅ and a small amount of Fe₂TiO₅ are formed in mullite refractory via the introduction of non-pre-fired titanite composite powder, which is not a dense Mosaic structure. In particular, the porosity increases during the formation of Al₂TiO₅, weakening the protective effect of iron oxide under reduction conditions, and resulting in more pores and cracks formed after the reduction atmosphere treatment. The stability cannot improve as TiO₂/Fe₂O₃ ratio increases. After reduction, the compressive strength of the sample is only 32.2-38.6MPa, showing a significant downward trend, and the attenuation rate is as high as 17.3%-26.5%.

Fe₂TiO₅ solid solution is formed in the pre-fired powder at 1300 ℃, and a large number of titanium oxide is coated iron titanate complex, forming a dense Mosaic structure in the corundum mullite matrix. Fe₂TiO₅ is formed during a progressive reduction of ferrous compound FeTiO₃, greatly inhibiting the reduction of iron oxide. Thus, the anti-reduction stability of the material is significantly improved. When the mullite refractory with m(TiO₂):m(Fe₂O₃) > 2.0 is added, the reduction stability is improved. The compressive strength remains 74.3-84.5 MPa at the reduction temperature of 1050 ℃, and the compressive strength attenuation rate at room temperature is only 2.6%-5.8%.

Conclusions

The results indicated that non-pre-sintered titanium-iron oxide composite samples exhibited a significant structural degradation after being treated at 950 ℃. This degradation was characterized via the formation of numerous micron-sized pores in the matrix and a weakening of the aggregate-matrix interface, leading to a peak compressive strength of only 38.6 MPa and a strength decay rate of 17.3%-26.5%. In contrast, pre-fired titanium-iron oxide composite samples maintained a good structural integrity after reduction at 1050 ℃. When a molar ratio of TiO₂/Fe₂O₃ exceeded 2, the compressive strength remained at 71.9 MPa. The microstructural analysis revealed little cracks in the samples, and the strength attenuation rate was controlled within 10%. In the non-pre-sintered titanium-iron oxide composites, the composite phase of Al₂TiO₅ and Fe₂O₃, which was introduced without pre-firing, could not effectively inhibit the reduction reaction of Fe₂O₃. This resulted in the precipitation of metallic iron and subsequent volume shrinkage. However, in the pre-fired composites, Fe₂TiO₅ was preferentially transformed into the ferrous compound FeTiO₃ during the reduction process. The resistance of the material to H₂/CO reduction erosion was enhanced via constructing a cooperative stable structure of Fe—O—Ti. This finding could provide a theoretical basis for the development of high-stability refractories for hydrogen-based shaft furnaces.

Key words

hydrogen-based shaft furnace / hydrogen/carbon monoxide atmosphere / titanium-iron oxide composite oxide / mullite-based refractories / reduction stability

引用本文

柯文丽, 廖宁, 颉付博, 李亚伟, 蔡国庆, 秦建涛. H₂/CO条件下氧化钛-氧化铁对莫来石质耐火材料稳定性的影响. 硅酸盐学报, 2025 , 53 (9) : 2586 -2596 . DOI: 10.14062/j.issn.0454-5648.20250085

Wenli KE, Ning LIAO, Fubo XIE, Yawei LI, Guoqing CAI, Jiantao QIN. Effect of Titanium Oxide/Iron Oxide on Stability of Mullite-Based Refractories Under H₂+CO Conditions[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (9) : 2586 -2596 . DOI: 10.14062/j.issn.0454-5648.20250085

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国家自然科学基金联合基金重点项目(U22A20127)

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2025年第53卷第9期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250085

接收时间：2025-02-12
首发时间：2026-10-21
出版时间：2025-09-20

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收稿日期：2025-02-12
修回日期：2025-03-04

基金

国家自然科学基金联合基金重点项目(U22A20127)

作者信息

^1．武汉科技大学，先进耐火材料全国重点实验室，武汉 430081

^2．山东耐材集团鲁耐窑业有限公司，山东淄博 255200

通讯作者:

廖宁（1988—），男，副教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250085

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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