镁锆砖的抗RH炉渣侵蚀机制

Corrosion resistance mechanism of magnesia zirconia brick to RH furnace slag

为实现RH炉的无铬化,以电熔镁砂、单斜锆为原料制备了ZrO2质量分数为11%的镁锆砖,并采用回转抗渣法进行镁锆砖和电熔再结合镁铬砖的抗高、低碱度RH炉渣对比试验,并分析了其抗渣机制。结果表明:(1)镁锆砖抗高碱度渣侵蚀性能较再结合镁铬砖强,但其抗低碱度渣侵蚀性能相对较差;在高碱度渣中形成含锆酸钙反应层是镁锆砖抗渣侵蚀性能优越的关键。(2)镁锆砖中的ZrO2吸收渣中的CaO而使渣碱度降低,黏度升高,从而使渣在镁锆砖中的渗透程度降低。(3)镁锆残砖的渣层含微量的ZrO2,从工作面到原砖层,镁锆残砖呈现出明显变质层、轻微变质层和原砖层3个段带,而镁铬残砖只有明显变质层和原砖2个段带;镁锆砖的SiO2含量在轻微变质层中最高,而镁铬砖的SiO2含量从工作面到原砖层逐渐减小。

Magnesia zirconia brick containing 11%（w）zirconia was prepared with magnesia and monoclinic zirconia as starting materials in order to replace the chrome-containing materials for RH furnace.The corrosion resistances of magnesia zirconia brick and fused rebonded magnesia chrome brick to high and low basicity slag of RH furnace were comparatively researched by rotary slag method and their slag resistance mechanisms were analyzed.The results show that：（1）because the reaction layer containing CaZrO3 forms in magnesia zirconia brick,it has better corrosion resistance to high basicity slag than rebonded magnesia chrome brick,however,it has worse corrosion resistance to low basicity slag than rebonded magnesia chrome brick;（2）ZrO2 in the magnesia zirconia brick can absorb CaO in the slag,which makes the basicity of slag decrease and the viscosity of slag increase,so the degree of slag penetration in magnesia zirconia brick decreases;（3）there is little zirconia in the slag layer of magnesia zirconia residual brick;from working face to original brick layer,the magnesia zirconia residual brick shows three zones：obvious deteriorative layer,slight deteriorative layer,and original brick layer,but the magnesia chrome residual brick only shows two zones：obvious deteriorative layer and original brick layer;the SiO2 content of magnesia zirconia residual brick is the highest in the slight deteriorative layer,however,the SiO2 content of fused magnesia chrome residual brick gradually decreases from working face to original brick layer.