煤灰渣在Cr_2O_3-Al_2O_3-ZrO_2砖表面润湿与渗入行为的研究

Coal ash slag wettability on Cr_2O_3-Al_2O_3-ZrO_2 bricks and its penetration behavior

将灰分(w)为6.81%,挥发分(w)为32.68%的煤制成煤灰后,压成圆柱形的煤灰柱放在Cr2O3(w)含量约为90%的Cr2O3-Al2O3-ZrO2砖上,再推入管式加热炉中,在Ar气氛下,通过升温试验(升温至1200℃)和保温试验(升温至1165℃保温20min),考察了煤灰渣在Cr2O3-Al2O3-ZrO2砖表面的润湿与渗入行为。结果表明无论是升温试验还是保温试验,煤灰柱的变化过程完全一致,都经历了变形、熔融和润湿等一系列的变化。对升温试验过程中煤灰柱变化的观察和照片的处理结果均表明煤灰柱在1100℃时局部凹进去形成不规则形状;在1165℃时煤灰完全熔化,煤灰柱变成半球形;在1180℃时接触角<90°,煤灰渣开始在Cr2O3-Al2O3-ZrO2砖表面发生润湿。对升温试验后的Cr2O3-Al2O3-ZrO2砖表面和渣表面的化学组成分析表明有大量Fe堆积在煤灰渣与Cr2O3-Al2O3-ZrO2砖表面接触处,而邻近处几乎没有发现Fe,可能是由于Fe与Cr2O3-Al2O3-ZrO2砖中的一些组分形成了某种晶相,使得Fe很难进入Cr2O3-Al2O3-ZrO2砖;接近煤灰渣的Cr2O3-Al2O3-ZrO2砖表面组成中出现了Ca,说明熔融灰渣中的Ca渗入Cr2O3-Al2O3-ZrO2砖;同时,煤灰渣中出现了Cr,表明在熔融灰渣渗入Cr2O3-Al2O3-ZrO2砖的同时,砖中的Cr也熔入了熔渣中。

The coal composed of 6.81% of ash and 32.68% of volatiles was burned into coal ash and shaped into a cylinder.The ash cylinder was then placed upon chrome corundum bricks and pushed into the tube furnace.In the Ar atmosphere,by rising-temperature test （temperature was raised to 1 200 ℃） and maintained-temperature test（the temperature was raised to 1 165 ℃ and held for about 20 min）,the wettability and the penetration of coal ash slag on chrome corundum bricks was investigated.The results showed that the ash cylinders in both tests experienced the coincident change sequence as.deformation, melting and wetting. By observing those changes and analyzing the photographs,the coal ash cylinder is partially depressed to form an irregular shape at 1 100℃. While at 1 165℃,the coal slag was fully molten and the cylinder changed into a semi-spherical shape. When the contact angle 〈 90°at ：1：180℃,the coal slag began to wet the brick surface. By analyzing the chemical compositions of the brick surface and slag surface after rising-temperature test, a large deal of iron content was found concentrated at the joints between slag and brick. But no Fe was found nearby probably because some crystal formed by reaction between Fe and components in the brick prevented the Fe from penetrating. Calcium was found in the brick surface close to the slag ,which shows Ca in the molten slag penetrated into the brick. Also chrome was found in the slag, which indicated that the Cr element in the brick melted into the slag simultaneously when the slag penetrated into the brick.