溶胶浸渍对镁铬砖性能的影响

Influence of impregnation by solon properties of magnesia-chrome bricks

采用化学法制备出的Cr(OH)_3溶胶和Mg(OH)_2-Cr(OH)_3混合溶胶分别对炼铜炉用镁铬砖进行真空浸渍。透射电子显微镜(TEM)观察发现,两种溶胶中的粒子分散均匀,均呈球形或近球形,平均粒径在50nm左右。对浸渍前后试样的理化性能和孔隙率进行了分析,结果表明:经两种溶胶浸渍后,试样的Cr_2O_3含量增加,耐压强度和体积密度略有升高,显气孔率显著下降;试样的体积中位径由浸渍前的17.45μm分别下降至浸渍后的9.56μm和12.24μm,孔径>12μm的气孔的数量由浸渍前的88.47%分别下降至浸渍后的40.65%和58.92%。SEM和EDS分析显示:两种溶胶浸渍后的试样经110℃处理后,通过镁铬砖的气孔进入并附着在气孔内壁上的纳米级的溶胶粒子均长大;而经1550℃处理后,这些粒子构成了试样的一部分。抗侵蚀试验结果表明,浸渍后试样抗炼铜转炉渣的侵蚀性比浸渍前试样的好。

Two kinds of sols, Cr（OH）3 sol and Mg （ OH ）2 - Cr（OH）3 sol, were prepared by chemical method and impregnated into magnesia-chrome refractory bricks for copper converter. Two particles ,were dispersed uniformly in the sols with spherical shape and average diameter of ones are both about 50 nm which were observed by Transmission Electron Micrograph （TEM）. The results from pore size distribution and physical -chemical analysis show that Cr2O3 contents of specimens increase,cold crushing strength and bulk density of specimens increase a little but apparent porosity decreases markedly after impregnation. Median pore diameters （volume） of specimens after impregnated by two sols reduce to 9.56 μm and 12.24μm respectively from 17.45μm before impregnation and amount of pore with diameter over 12μm reduces to 40.65% and 58.92% respectively from 88.47% before impregnation. The SEM and EDS analysis reveals that sol particles enter into pore inside of magnesia chrome brick and cling on the walls of pore and make up the constituent parts of magnesia chrome refractory brick after firing at 1550℃ for 3h. The corrosion resistance of specimens before and after impregnation to copper slag attack was carried out and the results revealed that the impregnated magnesia chrome brick had better slag corrosion resistance than the unimpreclnated bricks.