不同型号镁碳砖对抗富钒钢渣侵蚀性能的影响

Effect of different types of magnesia-carbon bricks on corrosion resistance of vanadium-rich slag

目前,提钒转炉采用镁碳砖作为炉衬,评估不同型号镁碳砖的侵蚀速率以及损毁机理对提高提钒转炉寿命具有重要的实用价值。在电阻炉条件下,采用静态抗渣方法模拟6种镁碳砖侵蚀情况,探讨镁碳砖抗富钒钢渣侵蚀及其机理。结果表明,MT-C12B、MT-C14A试样受熔渣冲刷、侵蚀后减薄较少,其中MT-C12B试样侵蚀面积所占比例为2.98%,MT-C14A试样侵蚀面积所占比例为2.74%。从试样侵蚀情况显微结构看,MT-C12B试样的脱碳层深度最小,对镁碳砖性能影响较小,为提钒转炉最优选择。6种镁碳砖侵蚀机理基本一致,镁碳砖中的石墨与钢渣中的V_(2)O_(3)、Cr_(2)O_(3)、FeO反应生成金属相,造成MgO颗粒的裸露,渣中V_(2)O_(3)随熔渣进入脱碳层并与在此处的MgO反应,在镁碳砖表面形成含钒尖晶石相(MgV_(2)O_(4));另外,液态渣相中的SiO_(2)、CaO等与MgO颗粒反应生成新的低熔点液渣相,进而完成方镁石的溶解过程。含钒尖晶石相在镁碳砖表面的生成可以显著增加脱碳层的致密化程度,阻止渣的进一步渗透,因此材料受侵蚀的速率逐渐下降,最终形成较为缓慢的侵蚀过程。研究结果可为提高提钒转炉炉衬寿命提供依据。

At present,magnesia-carbon brick is used as the lining of vanadium extraction converter.It is of great practical value to evaluate the erosion rate and damage mechanism of different types of magnesia-carbon bricks for improving the service life of vanadium extraction converter.The static slag resistance method was used to simulate the erosion of six kinds of magnesia-carbon bricks under the condition of resistance furnace,and the corrosion resistance and mechanism of magnesia-carbon bricks to vanadium-rich slag were discussed.The results show that MT-C12B and MT-C14A samples are less thinned after erosion by slag.Among them,the erosion area of MT-C12B accounts for 2.98%,and the erosion area of MT-C14A accounts for 2.74%.From the microstructure of the sample erosion,the decarburization layer depth of MT-C12B is the smallest,which has little effect on the performance of magnesia-carbon brick,and is the best choice for vanadium extraction converter.The corrosion mechanism of the six magnesia-carbon bricks is basically the same.The graphite in the magnesia-carbon brick reacts with V_(2)O_(3),Cr_(2)O_(3) and FeO in the slag to form a metal phase,resulting in the exposure of MgO particles.The V_(2)O_(3) in the slag enters the decarburization layer with the slag,reacts with MgO here,and forms a vanadium-containing spinel phase(MgV_(2)O_(4))on the surface of the magnesia-carbon brick.Moreover,SiO_(2) and CaO in the liquid slag phase react with MgO particles to form a new low melting point liquid slag phase,and then complete the dissolution process of periclase.The formation of vanadium-containing spinel phase on the surface of MgO-C brick can significantly increase the densification degree of decarburization layer and prevent the further penetration of slag.Therefore,the erosion rate of the material gradually decreases,and finally a relatively slow erosion process is formed.The research results can provide a basis for improving the lining life of vanadium extraction converter.