Effect of Spinels on Properties of MgO-Al2O3 Refractories for RH Snorkels

doi:10.19691/j.cnki.1004-4493.2021.03.001

China's Refractories ›› 2021, Vol. 30 ›› Issue (3): 1-6.DOI: 10.19691/j.cnki.1004-4493.2021.03.001

Effect of Spinels on Properties of MgO-Al₂O₃ Refractories for RH Snorkels

ZHAO Huizhong^*(), LI Jingjie

The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China

Online:2021-09-15 Published:2021-11-26
Contact: ZHAO Huizhong
About author:Zhao Huizhong is a professor of Wuhan University of Science and Technology, a doctoral supervisor, and a national model of teacher ethics. He graduated from Wuhan Iron and Steel Institute in 1987 and has been engaged in refractory teaching and scientific research for nearly 35 years. He has participated in the national key scientific and technological projects from the State Key Task 75 to State Key Task 95. His main research directions include refractories for new metallurgical technology, harmless treatment and resource utilization of metallurgical solid waste, etc. He has published more than 100 papers in academic journals including more than 60 papers in SCI.

Abstract

Abstract:

With satisfactory high temperature properties, thermal shock resistance and mechanical properties, refractories in the MgO-Al₂O₃ system have become promising alternative to MgO-Cr₂O₃ counterpart used as RH snorkel lining. High purity dead burned magnesia, fused magnesia and sintered spinel were used as raw materials and sulfite pulp waste as the binder, specimens of the refractories in the MgO-Al₂O₃ system were prepared for the purpose of investigating the influences in terms of the addition of three kinds of spinels, with Al₂O₃ 50%, 66% and 78%, by mass, respectively, and the size of MA50 spinel on properties of the specimens. Relatively superior comprehensive properties can be achieved when 16% of MA50 spinel with sizes under 1 mm is adopted.

Key words: magnesium aluminate spinel, magnesia-alumina refractories, RH snorkel, properties

ZHAO Huizhong, LI Jingjie. Effect of Spinels on Properties of MgO-Al₂O₃ Refractories for RH Snorkels[J]. China's Refractories, 2021, 30(3): 1-6.

Figures/Tables 22

Table 1 Chemical and physical properties of main starting materials

Starting materials	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	IL	True density /(g · cm^-3)	Particle density /(g · cm^-3)
Fused magnesia	2.06	0.25	0.67	1.44	92.88	0.27	3.62	2.86
High purity sintered magnesia	0.78	0.14	0.59	1.44	96.02	0.35	3.60	3.16
MA50 spinel	0.56	50.42	0.48	0.76	46.23	1.18	3.53	3.13
MA66 spinel	0.38	65.60	0.38	0.56	31.53	1.19	3.56	3.46
MA78 spinel	0.28	76.80	0.25	0.44	21.70	0.26	3.50	3.07

Fig. 1 Outlook of adopted spinel

Fig. 2 XRD patterns of three spinels

Table 2 Formulations for investigation of spinel addition effect /mass%

No.	MA50 spinel	High purity sintered magnesia		Fused magnesia fine powder
No.	3-1 mm	5-2 mm	2-0 mm	<0.088 mm
O	0	37	40	23
A	14	30	33	23
B	16	30	31	23
C	18	30	29	23
D	20	30	27	23

Fig. 3 Effect of spinel addition on permanent linear change

Fig. 4 Effect of spinel addition on apparent porosity and bulk density

Fig. 5 Effect of spinel addition on CMOR and CCS

Fig. 6 Effect of spinel addition on HMOR at 1 450 °C

Fig. 7 Effect of spinel addition on thermal expansion coefficients of specimens

Fig. 8 Effect of spinel addition on thermal shock resistance of specimens

Fig. 9 Effect of spinel type on permanent linear change of specimens

Fig. 10 Effect of spinel type on AP and BD of specimens

Fig. 11 Effect of spinel type on CMOR and CCS of specimens

Fig. 12 Effect of spinel type on HMOR at 1450 °C of specimens

Fig. 13 Effect of spinel type on thermal shock resistance of specimens

Table 3 Formulations for investigating influence of MA50 spinel size /mass%

Specimens	MA50 spinel	High purity magnesia		Fused magnesia
Specimens	MA50 spinel	5-2 mm	2-0 mm	<0.088 mm
With <0.088 mm spinel	16	40	37	7
With 1-0 mm spinel	16	31	33.5	19.5
With 1-3 mm spinel	16	30	31	23

Fig. 14 Effect of spinel size on PLC of specimens

Fig. 15 Effect of spinel size on AP and BD of specimens

Fig. 16 Effect of spinel size on cold strengths of specimens

Fig. 17 Effect of spinel size on HMOR at 1 450 °C of specimens

Fig. 18 Effect of spinel size on thermal expansion coefficient of specimens

Fig. 19 Effect of spinel size on thermal shock resistance of specimens

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Effect of Spinels on Properties of MgO-Al₂O₃ Refractories for RH Snorkels

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