骨料浸渍氧化铝浆体对高炉炭砖显微结构和性能影响

Microstructure and Properties of Carbon Blocks Containing Anthracite Aggregates Impregnated with Al2O3 Slurry

针对炭砖为主要原料电煅煤的多孔结构,采用真空浸渍浆体方法对电煅煤骨料进行处理来改善骨料的致密度,从而优化炭砖的微孔结构,提高炭砖性能。首先对电煅煤骨料进行真空浸渍氧化铝浆体处理,得到浸渍氧化铝电煅煤骨料(以下简称浸渍骨料),然后将浸渍骨料取代电煅煤骨料引入到炭砖中,借助场发射扫描电镜、压汞仪和CT扫描仪等研究了浸渍骨料对高温热处理后炭砖显微结构、微孔结构和性能的影响。结果表明:通过真空浸渍氧化铝方法,氧化铝填充进电煅煤骨料的开口气孔和裂缝中,使骨料更加致密。将浸渍骨料引入到炭砖中,炭砖经不同温度处理后的性能得到明显改善,如经1400℃处理后炭砖的耐压强度提高近50%,平均孔径降低至73 nm,<1μm孔容积率达到80%左右。炭砖性能的改善主要与引入更加致密的浸渍骨料和形成更多的原位陶瓷相有关。

As for the porous structure of anthracite raw materials for carbon blocks, anthracite aggregates were treated by slurry vacuum technology to improve the density of aggregates, thus optimizing the microporous structure and enhancing properties of carbon blocks. Anthracite aggregates impregnated with Al2O3(anthracite/Al2O3 aggregates) was firstly obtained by slurry vacuum infiltration method, which were then used as raw materials to fabricate carbon blocks by replacing normal anthracite aggregates. The effect of anthracite/Al2O3 aggregates on microstructure, micropore structure and properties of carbon blocks fired at elevated temperatures was studied with the aid of SEM, mercury porosimetry and CT scanner. The results show that Al2O3 infiltrate into the open pores and cracks of anthracite aggregates, thus densifying the anthracite aggregates. When introduced the anthracite/Al2O3 aggregates into carbon blocks, the properties of carbon blocks fired at various temperatures are improved remarkably in comparison with reference samples without anthracite/Al2O3 aggregates. For instance, the cold compressive strength of carbon blocks fired at 1400 ℃ is about 50% higher, mean pore diameter decreases to 73 nm and < 1 μm pore volume ratio reaches to 80%. The enhancement of carbon blocks is mainly related to the incorporation of denser anthracite/Al2O3 aggregates and formation of much more ceramic phase.