Formation of MgO dense layer and slag resistance of MgO-MA-Al materials

doi:10.3969/j.issn.1001-1935.2021.01.004

Abstract

Abstract:

MgO-MA samples and MgO-MA-Al samples containing 5 mass% metal Al were prepared using fused magnesia,fused spinel and aluminum as raw materials and phenolic resin as the binder.After drying at 110 ℃ for 24 h,some samples were heat treated in a closed sagger at 1 600 ℃ for 5 h to analyze their phase composition and microstructure;the other samples were tested for slag resistance at 1 600 ℃ in nitrogen atmosphere for 5 h.The results show that (1)a MgO dense layer is formed on the MgO-MA-Al sample containing 5 mass% Al since the strong reducing Al promotes the transformation of MgO to Mg gas during the heat treatment in the closed sagger at 1 600 ℃ for 5 h under nitrogen atmosphere;(2)in the process of the slag resistance test at 1 600 ℃ for 5 h in nitrogen atmosphere,the outer layer of the sample is also densified,which improves the slag penetration resistance and the slag corrosion resistance of the samples.

Key words: magnesia-spinel-aluminum composite, magnesia dense layer, oxygen partial pressure, slag resistance

摘要：

以电熔镁砂、电熔尖晶石和金属铝为原料,酚醛树脂为结合剂,制成MgO-MA和含有5%(w)金属Al的MgO-MA-Al试样。在110 ℃干燥24 h后,一部分试样在密闭匣钵中于1 600 ℃保温5 h热处理,分析其物相组成和显微结构;另一部分试样于氮气气氛1 600 ℃保温5 h进行抗钢渣试验。结果表明:1)在密闭匣钵于1 600 ℃保温5 h热处理过程中,含有5%(w)金属Al的MgO-MA-Al试样因强还原性单质Al的存在促进了MgO向Mg(g)转化,从而促进MgO致密层的形成。2)在氮气气氛1 600 ℃保温5 h进行抗渣试验的过程中,同样会发生试样外层致密化的过程。这使试样的抗渣渗透性和抗渣侵蚀性得到提高。

关键词: MgO-MA-Al复合材料, MgO致密层, 氧分压, 抗渣性

CLC Number:

TQ175

Gao Song, Wang Xiaoyu, Zhang Ju, Mu Yuandong, Ye Guotian. Formation of MgO dense layer and slag resistance of MgO-MA-Al materials[J]. Refractories, 2021, 55(1): 17-20.

高耸, 王晓雨, 张举, 穆元冬, 叶国田. MgO-MA-Al材料MgO致密层的形成及其抗渣性[J]. 耐火材料, 2021, 55(1): 17-20.

Figures/Tables 8

Table 1 Chemical composition of main raw materials

原料	w/%
原料	MgO	Al₂O₃	SiO₂	CaO	Al
电熔镁砂	97.54		0.60	0.35
电熔镁铝尖晶石粉	23.36	73.26	0.21
Al粉					99.2

Table 2 Experimental formulation

原料		w/%
原料		试样M0	试样M5
电熔镁砂	5~3 mm	10	10
	3~1 mm	35	35
	≤1 mm	20	20
	≤0.074 mm	20	15
电熔镁铝尖晶石粉	≤0.045 mm	15	15
Al粉	≤0.045 mm	0	5
酚醛树脂(外加)		1	1

Fig.1 Section images of M0 and M5 after heat treatment in closed sagger at 1 600 ℃ for 5 h

Fig.2 XRD pattern of white floccule on surface of M5

Fig.3 XRD patterns of M5(inner and surface) after heat treatment in closed sagger at 1 600 ℃ for 5 h and local magnification patterns

Fig.4 SEM images of M0 and M5 after heat treatment in closed sagger at 1 600 ℃ for 5 h

Table 3 EDS results of micro-regions in Fig.4

区域	x/%
区域	Mg	Al	O	N
1	54.36	1.37	44.27	—
2	16.28	25.46	58.26	—
3	8.46	34.82	22.13	34.59

Fig.5 Cross section images of M0 and M5 after slag resistance test at 1 600 ℃ for 5 h under nitrogen atmosphere

References 9

[1]	CHO M K, ENDE M A V, EUN T H, et al. Investigation of slag-refractory interactions for the Ruhrstahl Heraeus (RH) vacuum degassing process in steelmaking[J]. Journal of the European Ceramic Society, 2012,32(8):1503-1517. DOI URL
[2]	ZHU B H, LIU Q C, KONG M, et al. Effect of interphase forces on gas-liquid multiphase flow in RH degasser[J]. Metallurgical and Materials Transactions B, 2017,48(5):2620-2630. DOI URL
[3]	SUNAYAMA H, KAWAHARA M. Effect of dense layer formation on dissolution rate of MgO-C refractory in molten slag[J]. Advances in Science and Technology, 2006,45:162-166. DOI URL
[4]	CHEN J F, LI N, YAN W, et al. Influence of Ti₃AlC₂ on microstructure and thermal mechanical properties of Al₂O₃-Ti₃AlC₂-C refractories[J]. Ceramics International, 2016,42(12):14126-14134. DOI URL
[5]	LI T Q, LI N, YAN W, et al. Degradation of low-carbon MgO-C refractory by high-alumina stainless steel slags in VOD ladle slagline[J]. International Journal of Applied Ceramic Technology, 2017,14(4):731-737. DOI URL
[6]	LI X C, ZHU B Q, WANG T X. Effect of electromagnetic field on slag corrosion resistance of low carbon MgO-C refractories[J]. Ceramics International, 2012,38(3) : 2105-2109. DOI URL
[7]	于景坤, 刘承军. 镁碳耐火材料表面MgO致密层的形成机理[J]. 耐火材料, 2002,36(3):125-127.
[8]	于景坤, 刘承军. 影响镁碳耐火材料表面MgO致密层形成的因素[J]. 耐火材料, 2002,36(4):190-193.
[9]	李晓明. 镁碳砖致密MgO层形成的热力学计算[J]. 硅酸盐通报, 1988(5):18-21.

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