改性石墨对Al_2O_3-SiC-C质铁沟浇注料性能的影响

Effect of modified graphite on properties of Al_2O_3-SiC-C castables for BF trough

为了解决鳞片石墨因密度小、润湿性差和分散困难而难以在浇注料中使用的问题,首先采用硅烷偶联剂KH-560对≤0.178和≤0.074 mm的鳞片石墨分别进行改性处理,得到两种粒度的改性石墨;然后在传统Al2O3-SiC-C质铁沟浇注料配方(w):电熔致密刚玉62%、SiC粉24%、α-Al2O3微粉5%、纯铝酸钙水泥4%、SiO2微粉3%、球状沥青(≤1 mm)2%的基础上,分别用0.5%(w)的改性前后的石墨等量取代球状沥青,以研究KH-560硅烷偶联剂改性鳞片石墨对Al2O3-SiC-C铁沟浇注料性能的影响。结果表明:与原石墨相比,改性后石墨的分散性明显改善,浇注料的需水量大幅降低,且加入≤0.178 mm改性石墨的试样分散效果较好;含石墨试样的常温物理性能均有所下降,但加入≤0.178 mm改性石墨的试样强度和体积密度都明显高于加入其他石墨的,仅略低于无石墨的;加入石墨的试样抗渣性能明显得到提高,且加入≤0.178 mm改性石墨试样的抗渣性能最佳。综合考虑浇注料的各项性能,认为经硅烷偶联剂改性的鳞片石墨可部分取代球状沥青,且最佳粒度为≤0.178 mm。

Two modified graphites with different particle sizes were prepared using silane coupling agent KH - 560 treated flake graphites （ ≤0. 178 and ≤0. 074 mm） in order to solve the problem that the flake graph-ite cannot be used in castables due to low density, poor wettability and poor dispersibility. Based on the formulation of traditional Al2O3-SiC-C castables for trough （62% dense fused corundum （in mass, the same hereinafter） ,24% SiC powder,5% α-Al2O3 micropowder,4% pure calcium aluminate cement,3% sili-ca fume and 2% ball pitch （ ≤1 mm））,0.5% of flake graphites before and after modifying were used to replace the equivalent ball pitch, respectively. Effects of the modified flake graphites on properties of Al2O3 -SIC-C castables for iron trough were researched. The results show that, compared with the original graphites, the dispersibility of the modified graphites improves obviously, the water demand of the castables decreased greatly, and the specimen with the modified graphite （ ≤0. 178 mm） performs the best dispersibility;all the cold physical properties of the specimens with the original graphites decrease, the specimen with the modified graphite （ ≤0. 178 mm） performs higher strength and bigger density than the other specimens ,except for the specimen without graphite;the slag resistance of the specimens with graphite is improved,and the specimen with the modified graphite （ ≤0. 178 mm） performs the best slag resistance. Considering the properties of the castables,the modified flake graphite treated by the silane coupling agent KH-560 can partially replace the ball pitch, and the optimal particle size of the modified graphite is ≤0. 178 mm.