Optimization of Properties for Alumina-Spinel Refractory Castables by CMA (CaO-MgO-Al2O3) Aggregates.

Hai Tang,Wenjie Yuan,Bruno Touzo,Chunxue Li,Jianying Gao,Chunfeng Liu

doi:10.3390/ma14113050

Abstract

Aiming at optimizing properties of alumina-spinel refractory castables, coarse corundum particles were replaced partially with the particles of a novel porous multi-component CMA (CaO-MgO-Al2O3) aggregate in the same size. Properties including the bulk density, apparent porosity, strength, slag corrosion resistance, thermal shock resistance and thermal fatigue resistance of alumina-spinel refractory castables containing CMA aggregates were evaluated contrastively. The results demonstrated that the incorporation of CMA aggregates can significantly improve thermal shock resistance and thermal fatigue resistance of castables, although companying with slight decrease in the bulk density and strength. Moreover, slag penetration resistance of castables can also be enhanced by CMA aggregates with appropriate particle size. The influence of CMA aggregates on properties of alumina-spinel refractory castables depended strongly on their particle size.

Highlights

Alumina-magnesia and alumina-spinel castables have been widely used in steel ladle linings below the slag zone, the well block of purging plugs, and injection lances due to their excellent slag resistance and mechanical properties [1,2]
The exploitation of novel porous aggregates successfully broke the traditional concept, and it became a hot topic in refractories [3,4,5,6,7]
The corrosion mechanism of aluminaspinel castables with CMA aggregates addition has been demonstrated by Wöhrmeyer et al The results indicated that a thin densified zone formed and blocked the slag penetration into the porous matrix and the porous aggregates [16]

Summary

Introduction

Alumina-magnesia and alumina-spinel castables have been widely used in steel ladle linings below the slag zone, the well block of purging plugs, and injection lances due to their excellent slag resistance and mechanical properties [1,2]. In view of the increasing ratio of scrap to steel, higher working temperature, and prolonged refining time, the enhanced properties of materials, especially for the slag resistance and thermal shock resistance are required to adapt tougher service condition. The slag penetration is reduced by using dense aggregates and designing the matrix with lower porosity through filling with fine powders. The dense aggregates and matrix are hardly to release the thermal stress under the great temperature gradient. It is necessary to optimize the slag resistance and thermal shock resistance simultaneously. The exploitation of novel porous aggregates successfully broke the traditional concept, and it became a hot topic in refractories [3,4,5,6,7]

Objectives

Methods

Conclusion