2023 Vol.32, No.3 Date of publication: 15 September 2023

Corrosion of Basic Refractories for Glass Tanks Using Petrol Coke and Countermeasures

Replacing heavy oil with petrol coke can greatly reduce the cost of glass production, but obviously shorten the service life of refractories used in the regenerator checker body of glass tanks. To prolong the service life of the regenerator checker body, the slag chemical composition and alkali-sulfur ratio of glass tanks after using petrol coke and the damage mechanism of the residual magnesia bricks in the regenerator checker body were studied, as well as the corrosion resistance of three magnesia based bricks (direct bonded magnesia chrome bricks, fused rebonded magnesia chrome bricks, and fused rebonded high- purity magnesium aluminate spinel bricks). On this basis, a series of targeted countermeasures were adopted to optimize the configuration of refractories, significantly improving the service life of checker bricks and meeting the requirements of glass industry development.

XU Linlin, LIU Zhao, WANG Jiezeng, CHEN Songlin, LIU Xijun

2023 Vol.32 (3): 1-5. doi:10.19691/j.cnki.1004-4493.2023.03.001

Effect of Ferric Nitrate Loading Mode on Properties of Si₃N₄ Composite MgO-C Refractories Prepared by Nitridation

In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si₃N₄ composite MgO-C refractories prepared by nitridation, fused magnesia, flake graphite, silicon powder, and phenolic resin were used as the main raw materials, and ferric nitrate as the catalyst to prepare refractories by nitriding at 1 350 °C. The effects of different catalyst supports (silicon powder, silicon powder + phenolic resin) on the formation of Si₃N₄ in MgO-C refractories and the properties of refractories were studied. The results show that the silicon powder + resin catalyst support promotes the participation of α-Si₃N₄ in the reaction to generate β-Si₃N₄ and MgSiN₂, and generates more SiC. However, this loading mode causes more gas to escape from the refractories and loosens the material structure, which reduces the mechanical properties. On the contrary, MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.

CHEN Yang, DENG Chengji, DING Jun, YU Chao, LOU Xiaoming

2023 Vol.32 (3): 6-9. doi:10.19691/j.cnki.1004-4493.2023.03.002

Analysis of Corrosion Behavior of ZrO₂-C Slag-line Materials in Continuous Casting

In view of the service failure and low continuous casting production efficiency due to the corrosion of refractories at the slag-line in submerged entry nozzles, a submerged entry nozzle for low-carbon aluminum killed steel continuous casting in one steel plant was sampled and taken as the research object to analyze the causes and the mechanism of refractory corrosion at the slag-line. The results show that the core issue of the corrosion and necking of the slag-line materials is that the slag-line material are eroded, dissolved, and reacted by the mold flux gradually. Therefore, it is important to suppress or avoid the contact and reaction between the mold flux and slag-line materials.

TIAN Chen, ZHI Jianjun, GAN Feifang, FAN Zhengjie, GAO Hua, YUAN Lei, LIU Guoqi, YU Jingkun, LI Hongxia

2023 Vol.32 (3): 10-13. doi:10.19691/j.cnki.1004-4493.2023.03.003

Effect of Al Powder and Si Powder Additions on Structure and Properties of Unburned Magnesium Aluminate Spinel Refractories

Unburned magnesium aluminate spinel refractories were prepared using sintered magnesium aluminate spinel as the main raw material, phenolic resin as the binder, aluminum powder (2%, 4%, and 6% by mass) and silicon powder (when Al powder addition is 4%, Si powder addition varies: 1% and 2%, by mass) as additives. The effects of the Al powder and Si powder additions on the properties and microstructure of the refractories heat treated at different temperatures (1 000, 1 400, and 1 600 ℃ for 3 h) were studied. The results show that the Al powder addition can greatly enhance the cold modulus of rupture of the samples fired at 1 000 or 1 400 ℃, and meanwhile AlN reinforcement phase forms in the matrix, which greatly improves the hot modulus of rupture of the samples at 1 400 ℃; however, the heat treatment at 1 600 ℃ has little influence on the strength; the addition of Al powder and Si powder results in the formation of low melting point phases, greatly reducing the hot modulus of rupture. However, the low melting point phases promote sintering, which enhances the density and the cold modulus of rupture, and decreases the volume change during heating. The samples added with Al and Si all have higher cold modulus of rupture than those added with Al powder only.

ZHOU Lianzhuo, WANG Zhoufu, WANG Xitang, LIU Hao, MA Yan, QUAN Zhenghuang

2023 Vol.32 (3): 14-19. doi:10.19691/j.cnki.1004-4493.2023.03.004

Preparation of Lightweight Alumina-silica Castables by Replacing Closed-cell Perlite Aggregates with Coal Gangue Ceramsites

Lightweight alumina-silica castables were prepared using closed-cell perlite (2-4 mm), open-cell perlite (4-6 mm) and coal gangue ceramsites (2-5 mm) as aggregates, floating beads (0.3-0.5 mm), sinking beads (0.6-0.8 mm), silica micropowder, α-Al₂O₃ micropowder, zirconia and zircon micropowder as fines, and Secar 71 cement (calcium aluminate cement) as the binder. The effects of the coal gangue ceramsites addition (0, 6%, 12%, 18% and 24%, by mass) on the properties of the as-prepared lightweight alumina-silica castables were investigated. The results show that: (1) the addition of coal gangue ceramsites can reduce the sintering shrinkage of the specimens and help to improve the strength and thermal shock resistance; (2) the samples with the addition of coal gangue ceramsites can produce pores in the matrix of the sintered samples, which provides enough space for the growth of CA₆ complex solid solution and expands the irregular lamellar structure; (3) with the addition of coal gangue ceramsites increasing, the linear shrinkage of the samples heat treated at 1 000 or 1 200 ℃ firstly reduces and then increases, the bulk density increases and the apparent porosity decreases; the cold compression strength and the thermal shock resistance of the specimens heat treated at 1 200 ℃ firstly increase and then decrease. Thus, the optimal addition of coal gangue ceramsites is 18%.

ZAN Wenyu, MA Beiyue

2023 Vol.32 (3): 20-25. doi:10.19691/j.cnki.1004-4493.2023.03.005

Performance of Adsorbents for NO₂ in Furnace Flue Gas

To meet the emission standard of nitrogen oxides (NO_x) in the flue gas of batch furnaces through dry adsorption, a calcium-silica inorganic adsorbent was prepared with limestone and quartz as raw materials. Sample Cu-BTC 1^# was obtained by solvothermal synthesis, drying and purification in vacuum at 120 ℃ using trimesic acid (H₃BTC) and copper nitrate trihydrate (Cu(NO₃)₂·3H₂O) as raw materials; likewise, sample Cu-BTC 3^# was obtained at 200 ℃. Sample Cu-BTC 2^# was obtained by hydrothermal synthesis, drying and purification in air (metal-organic frameworks, 1,3,5-benzene tricarboxylic acid copper). The two types of materials were tested in terms of the NO₂ adsorption, and then the specific surface area, pore volume, NO₂ adsorption performance, phase composition, microstructure and thermal stability of the adsorbent materials were explored via N₂ physical adsorption-desorption, SEM, XRD and TG characterization. The results show that: (1) the Cu-BTC samples have higher adsorption capacity than the calcium-silica adsorbent, in which sample Cu-BTC 3^# has the largest specific surface area and pore volume, thus adsorption capacity for NO₂; (2) the calcium-silica adsorbent has better thermal stability and lower total mass loss during the entire process than the Cu-BTC samples; sample Cu-BTC 2^# has the best thermal stability among the three Cu-BTC samples, and the metal Cu active sites of the Cu-BTC samples can be exposed at least above 150 ℃.

KONG Yuan, LI Xiang, FU Jie, YANG Lujun, WANG Anxiu, KANG Jialiang, SUO Dong, TIAN Shishuai, MA Chengliang

2023 Vol.32 (3): 26-30. doi:10.19691/j.cnki.1004-4493.2023.03.006

Effect of Porogenic Agents on Properties of Microporous Mullite Aggregates

Microporous mullite aggregates were prepared from bauxite by dry pressing and firing at 1 700 ℃ for 3 h with corn starch, PMMA microspheres or rice husk powder as the porogenic agent. The effects of some porogenic agents and their additions (mass fraction of 0, 5%, 10%, 15% and 20%, respectively) on the properties of the microporous mullite aggregates were analyzed by XRD, SEM and Image-Pro Plus software. The results show that the comprehensive performance of the sample with 10% rice husk powder is the best: the closed porosity is 7.1%; the bulk density is 2.63 g·cm^-3; the compressive strength is 122 MPa; the median pore size is 15.16 μm; and the thermal conductivity at 500 ℃ is 2.30 W·m^-1·K^-1.

JIN Zhishang, SHAN Zhilin, ZHAO Huizhong, YU Jun, ZHANG Han

2023 Vol.32 (3): 31-35. doi:10.19691/j.cnki.1004-4493.2023.03.007

Binder Effect on Properties of Cr₂O₃-bearing Corundum-based Refractory Castables

Cr₂O₃-bearing castables bonded with reactive MgO (RM) or calcium aluminate cement (CAC) were studied to evaluate the binder effect on their performance in corrosive environments. The properties of the as-prepared castables were compared with respect to the differences in phase composition and microstructure. The corrosion behavior of the as-prepared castables by CaO-Al₂O₃-Fe₂O₃-SiO₂-based slag was systematically compared via refractory cup testing at 1 600 ℃ with respect to the differences in phase composition and microstructure. The analysis indicates that RM bonded castables show higher apparent porosity, lower bulk density and strengths after drying at 110 ℃ and firing at 1 300 ℃, and higher permanent linear change after firing at 1 300 ℃, but better slag corrosion and infiltration resistance compared with CAC bonded castables.

ZHANG Hongrui, CHEN Liugang

2023 Vol.32 (3): 36-41. doi:10.19691/j.cnki.1004-4493.2023.03.008

Ultra-high Temperature Ceramic Coatings: A Review on Preparation Technology and Development Prospect

Ultra-high temperature ceramic coatings have ultra-high melting points, excellent mechanical properties and high temperature ablation resistance. These unique performance combinations turn it into a promising material for use in extreme environment structures in rockets and hypersonic vehicles, particularly nozzles, leading edges and engine components. In this paper, various preparation methods of ultra-high temperature ceramic coatings were reviewed, including plasma spraying, chemical vapor deposition, pack cementation, slurry sintering, hot pressing and their research progress. Meanwhile, some new preparation methods of high temperature coatings, such as ion beam deposition, ultrasonic spraying, metal organic frame work coating, and magnetron sputtering, were introduced. The development trend of ultra-high temperature coatings was prospected as well.

LIU Shijie, WANG Li, DONG Binbin, XU Biao, GUO Yusen, MIN Yongchao, GUO Yanyan, WEI Haoyu, ZHANG Keke, YIN Chaofan

2023 Vol.32 (3): 42-49. doi:10.19691/j.cnki.1004-4493.2023.03.009

Abstracts from Naihuo Cailiao (Refractories)

2023 Vol.32 (3): 50-54.

China's Refractories

Corrosion of Basic Refractories for Glass Tanks Using Petrol Coke and Countermeasures

Effect of Ferric Nitrate Loading Mode on Properties of Si₃N₄ Composite MgO-C Refractories Prepared by Nitridation

Analysis of Corrosion Behavior of ZrO₂-C Slag-line Materials in Continuous Casting

Effect of Al Powder and Si Powder Additions on Structure and Properties of Unburned Magnesium Aluminate Spinel Refractories

Preparation of Lightweight Alumina-silica Castables by Replacing Closed-cell Perlite Aggregates with Coal Gangue Ceramsites

Performance of Adsorbents for NO₂ in Furnace Flue Gas

Effect of Porogenic Agents on Properties of Microporous Mullite Aggregates

Binder Effect on Properties of Cr₂O₃-bearing Corundum-based Refractory Castables

Ultra-high Temperature Ceramic Coatings: A Review on Preparation Technology and Development Prospect

Abstracts from Naihuo Cailiao (Refractories)

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