Enhancing the Oxidation Resistance of Al2O3-SiC-C Castables via Introducing Micronized Andalusite.

Xiaoyu Wang,Ruijie Zhao,Chris Parr,Saixin Wang,Yuandong Mu,Guotian Ye,Qingfeng Wang

doi:10.3390/ma14174775

Xiaoyu Wang, Ruijie Zhao + Show 5 more

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https://doi.org/10.3390/ma14174775

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Abstract

Additions of andalusite aggregates (19 wt%) were shown in previous literature to enhance the antioxidation of Al2O3-SiC-C (ASC) castables. This work aims to investigate whether micronized andalusite has a greater influence on antioxidation improvement than andalusite aggregates. Various low contents (5 wt% and below) of micronized andalusite (≤5 μm) were introduced as a substitute for brown fused alumina in the matrix of ASC castables. The antioxidation of castable specimens was estimated by the oxidized area ratio on the fracture surface after a thermal shock test. The microstructure and phases of micronized andalusite and the castable specimens were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The results suggest that the antioxidation effects of ASC castables with a low addition of micronized andalusite are effectively enhanced. The heat-induced transformation of andalusite produces SiO2-rich glass, favoring the sintering of the castable matrix and impeding oxygen diffusion into the castable’s interior. Therefore, the castable antioxidation is enhanced without deteriorating the hot modulus of rupture.

Highlights

IntroductionAl2 O3 -SiC-C (ASC) castables are widely employed in blast furnace runners for their excellent thermal shock resistance and erosion resistance [1,2]
D8 advance, Bruker, Karlsruhe, The antioxidation effect of ASC castables is evaluated through photographs and the many) wasindex applied to detect the micronized andalusite phasecross-sections compositions after firing at oxidation
ASC castables evaluated through photographs and the specimen F1, and the oxidized thickness is declines with the elevated micronized anspecimen

Summary

Introduction

Al2 O3 -SiC-C (ASC) castables are widely employed in blast furnace runners for their excellent thermal shock resistance and erosion resistance [1,2] These favorable properties are mainly obtained from SiC and carbon/graphite (C) additions, which have a low wettability to molten iron and slags and provide thermal shock resistance [3,4]. Antioxidants are generally added to inhibit the oxidation of carbonaceous materials in castables. In this regard, the effect of various antioxidants (such as Si, B4 C, Si2 BC3 N, etc.) on the oxidation resistance of ASC castables has been widely studied [5,6,7]

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