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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2024, Vol. 43 ›› Issue (2): 719-726.

Special Issue: 耐火材料

• Refractory Materials • Previous Articles     Next Articles

Effect of MgCl2·6H2O Solution on Properties of Periclase-Magnesia Alumina Spinel Refractories

WANG Xin1, HAN Bingqiang1, MIAO Zheng2, CHEN Junfeng1, YAN Wen1   

  1. 1. The State Key Laboratory of Refractory and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China;
    2. Hebei Guoliang New Materials Co., Ltd., Tangshan 063022, China
  • Received:2023-08-22 Revised:2023-09-27 Online:2024-02-15 Published:2024-02-05

Abstract: Fused magnesia and fused magnesia alumina spinel were used as raw materials to prepare periclase-magnesia alumina spinel refractories, with three different concentrations of MgCl2·6H2O solution at 18 °Be′, 24 °Be′ and 30 °Be′ and phenolic resin as bonding agent. The effect of MgCl2·6H2O solution on cold modulus of rupture, cold crushing strength, sintering properties and thermal shock resistance of refractories was investigated by using phenolic resin as control group. The mechanisms of MgCl2·6H2O solution action on refractories were elucidated. The results show that MgCl2·6H2O solution reacts with magnesia to generate magnesium oxychloride cement (MOC) at room temperature, and the microstructure of MOC is interwoven interlocked whiskers, which makes the refractories show supervise mechanical strength after drying. The cold crushing strength of refractories reaches 79.1 MPa when the fire temperature is 1 700 ℃ and the solution concentration is 24 °Be′,which is 58.2% higher than that of phenolic resin. The apparent porosity of refractories reduces to 16.8% when the firing temperature is 1 700 ℃ and the solution concentration is 18 °Be′, which is 13.4% lower than that of phenolic resin. The increase of MgCl2·6H2O solution concentration is beneficial to improve fracture toughness of material. MOC and Mg(OH)2 decompose to produce reactive MgO during firing process, which promotes the sintering of refractories. In addition, the quasi-spherical MgO produced by decomposition disperses and fills in the internal cracks of magnesia particles, forming a microporous structure inside refractories, which is conducive to mitigating thermal stress impact during thermal shock.

Key words: MgCl2·6H2O solution, periclase-magnesia alumina spinel, magnesium oxychloride cement, quasi-spherical MgO, sintering densification, thermal shock resistance

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