Nano Al2O3 and MgO composite ceramic bonded spinel-magnesia fireproof casting material and preparation method thereof

Abstract

The invention relates to a nano Al2O3 and MgO composite oxide ceramic bonded spinel-magnesia fireproof casting material and a preparation method thereof. Al(OH)3 and Mg(OH)2 composite sol suspension is used as a nano ceramic bond, directly added into a mixture and subjected to in-situ synthesis reaction to form a nano structural matrix using spinel and magnesia as main components so as to form the nano spinel-magnesia fireproof casting material. The mixing materials of the casting material are characterized in that the spinel is used as aggregate or proper amount of sintered magnesia of less than or equal to 5 millimeters is added into the spinel aggregate to improve the total MgO content of the casting material; and the matrix material consists of a nano ceramic bond system, magnesia, little AlO3 with different properties and admixture, wherein after the synthesis reaction of the secondary spinel, the matrix material swells and is densified under constraint so as to cause the improvement of macrostructure and microstructure, improvement of performance and enhancement of durability and form the spinel-magnesia casting material with more excellent corrosion resistance and soakage resistance. The casting material is used in slag lines in integral secondary refining ladles, and obtains good using effect.

Description

technical field [0001] The invention belongs to the technical field of refractory materials, and in particular relates to a nano-composite oxide ceramic bonded spinel-magnesia refractory castable for an integral ladle used in secondary refining of steelmaking. Background technique [0002] In recent years, the main trend in the development of refractory technology is to continuously increase the use of monolithic materials or unshaped refractory materials, especially refractory castables. The output of castable materials in many countries has exceeded more than half of the total output of refractory materials, especially in The use of castables in the Japanese iron and steel industry has reached 70%. "P303-309]. This is mainly due to the fast and easy mechanized furnace building and its more excellent performance and good use effect with shaped products. From the perspective of steelmaking and refining technology, the fundamental purpose of implementing the overall ladle i...

AI Technical Summary

Problems solved by technology

However, with the increase of the secondary refining ratio, the load on the ladle lining is larger than before. The current situation is that with the increase of treatment time and temperature, and the high alkalinity of the treatment slag, the aluminum-spinel The service life of stone refractory castables is significantly reduced, which brings certain difficulties to the implementation and development of secondary refining technology

On the other hand, this aluminum-spinel castable itself has some defects in performance, the main reaction is that the resistance to slag erosion and slag penetration is relatively poor, so cracks, peeling, and falling off often occur in actual use. Blocks and other damage forms lead to a further reduction in service life and a situation that does not meet the requirements of secondary refining. Therefore, the secondary refining integral ladle lining increasingly requires new materials with high durability.

[0004] Nano-Al of the present invention 2 o 3 The main technical characteristics of the spinel-magnesia refractory castable combined with MgO composite oxide ceramics are as follows: First, the castable is made of Al(OH) 3 and Mg(OH) 2 The composite sol is used as a nano-ceramic binder, and is directly added to the mixture to form a spinel-magnesia refractory castable with a nanostructure matrix mainly composed of spinel and magnesium oxide through an in-situ synthesis reaction; In terms of castables for ladles, a new variety of high-durability spinel-magnesia refractory castables has been developed, which has significantly improved both slag erosion resistance and slag penetration resistance, and solved the problem of aluminum-spinel refractory castables used in the past. There is a contradiction between the slag erosion resistance and slag penetration resistance of stone castables, that is, in aluminum-spinel castables, when the content of MgO and spinel is increased, although the slag erosion resistance can be improved, However, the resistance to slag penetration is significantly reduced, which eventually leads to cracks and spalling damage.

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