超细微晶石墨对电煅煤基高炉炭砖显微结构和性能的影响
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摘要
以电煅煤和活性α-Al_2O_3微粉为主要原料,硅粉和铝粉为添加剂,在埋碳条件下经1200℃和1400℃焙烧处理后制备出电煅煤基高炉炭砖(以下简称炭砖)。在炭砖中添加超细微晶石墨,借助X射线衍射仪、场发射扫描电子显微镜、激光导热仪和压汞仪研究了超细微晶石墨的引入对炭砖物相组成、显微结构、导热性能及孔结构的影响,并与引入相同量鳞片石墨的试样作对比。结果表明:实验所用超细微晶石墨晶粒尺寸细小,并且呈现出薄片状结构,与电煅煤相比具有更高的反应活性。在炭砖中引入超细微晶石墨,促进了材料中碳化硅晶须的生成,提高了材料的耐压强度和导热系数,增大了材料中<1μm气孔的孔容积率。与添加相同含量鳞片石墨的试样相比,含超细微晶石墨试样的导热系数和平均孔径与其相当,耐压强度更优,在炭砖中具有很好的应用前景。
Electrically calcined anthracite based carbon blocks( hereinafter abbreviated to carbon blocks)were prepared by using anthracites,α-Al2 O3,Si and Al as main raw materials and fired at 1200 ℃ and1400 ℃ in coke bed. The effect of addition of ultrafine microcrystalline graphite on the phase composition, microstructure, thermal conductivity and micropore structure of carbon blocks was investigated with the method of XRD,SEM,laser thermal conductivity meter and mercury porosimetry.Same amount of graphite flake was also introduced into carbon blocks as a contrast. The result shows that ultrafine microcrystalline graphite consisted of very small particles and mainly presents as sheet-like structure,which has higher reactivity than anthracite. When incorporated into carbon blocks,ultrafine microcrystalline graphite accelerates the formation of SiC whiskers,thus the cold compressive strength and thermal conductivity is improved and < 1 μm pore volume ration of carbon blocks is increased. Compared to carbon blocks with same addition amount of graphite flake,the thermal conductivity and mean pore diameter of carbon blocks containing ultrafine microcrystalline graphite is about the same,but the cold compressive strength is better,indicating that ultrafine microcrystalline graphite has promising application prospects in carbon blocks.
Electrically calcined anthracite based carbon blocks( hereinafter abbreviated to carbon blocks)were prepared by using anthracites,α-Al2 O3,Si and Al as main raw materials and fired at 1200 ℃ and1400 ℃ in coke bed. The effect of addition of ultrafine microcrystalline graphite on the phase composition, microstructure, thermal conductivity and micropore structure of carbon blocks was investigated with the method of XRD,SEM,laser thermal conductivity meter and mercury porosimetry.Same amount of graphite flake was also introduced into carbon blocks as a contrast. The result shows that ultrafine microcrystalline graphite consisted of very small particles and mainly presents as sheet-like structure,which has higher reactivity than anthracite. When incorporated into carbon blocks,ultrafine microcrystalline graphite accelerates the formation of SiC whiskers,thus the cold compressive strength and thermal conductivity is improved and < 1 μm pore volume ration of carbon blocks is increased. Compared to carbon blocks with same addition amount of graphite flake,the thermal conductivity and mean pore diameter of carbon blocks containing ultrafine microcrystalline graphite is about the same,but the cold compressive strength is better,indicating that ultrafine microcrystalline graphite has promising application prospects in carbon blocks.
引文
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[5]李亦韦,桑绍柏,李亚伟.支持向量机算法对电锻煤基炭砖导热性能的优化及预报[J].硅酸盐通报,2015,34(1):43-49.
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[7]何月德,刘洪波,洪泉,等.酚醛树脂炭包覆对天然微晶石墨电化学性能的影响[J].功能材料,2013,44(16):2397-2400.
[8]梁雄,李亚伟,张雨,等.提纯土状石墨对铝碳材料显微结构和力学性能的影响[J].硅酸盐学报,2014,42(3):357-365.
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[10]王恒,李亚伟,桑绍柏,等.镍负载超细微晶石墨对铝碳耐火材料显微结构和力学性能的影响[J].人工晶体学报,2014,43(7):1815-1822.
[11] Wang X,Gai G S,Yang Y F,et al. Preparation of natural microcrystalline graphite with high sphericity and narrow size distribution[J]. Powder Technology,2008,181(1):51-56.
[12] Li Y W,Wang Q H,Fan H B,et al. Synthesis of silicon carbide whiskers using reactive graphite as template[J]. Ceramics International,2014,40(1):1481-1488.