为分析水泥回转窑用MgO-FeAl2 O4砖的侵蚀机制，采用荧光光谱、扫描电镜对水泥窑烧成带用MgO-FeAl2 O4砖原砖和用后砖的疏松层、过渡层、类原砖层进行了分析，推测了其在使用中的物理化学变化。结果显示，除水泥熟料与砖的作用外，硫、氯、钾等组分的渗透以及由此引起的物理化学作用，是造成砖损毁的重要原因。疏松层存在多种化合物包括简单的硫酸盐和硅酸盐以及成分复杂的铝方柱石类，由于它们不匹配的热膨胀系数，使该层变得尤其疏松、易剥落；氧化钾是过渡层中的最大有害物质，它能侵蚀镁砂和尖晶石颗粒；类原砖层中只有少量氯化钾和含氟杂质，冷端与原砖层的杂质成分近似。在残砖的整个厚度区域都发现钾盐，说明其渗透能力远超过其他组分，耐火砖一旦遇冷，这些钾盐便成为裂纹的诱发剂，降低砖的使用寿命。
To analyze the wear mechanism of MgO-FeAl2 O4 bricks,the original brick,and loose layer,transi-tion layer,and quasi-original layer of the used brick were investigated using X-ray fluorescence spectrome-try (XRF),scanning electron microscope (SEM)and energy dispersive spectroscopy (EDS)to deduce the physicochemical changes during service.The results show that:(1 )besides the interaction between the cement clinker and the brick,the more severe damage of the brick originates from the penetration of sulfur, chloride and potassium,etc.and the aroused physicochemical changes;(2)in the loose layer of the used brick,there exist various compounds including simple sulfate salt and silicate salt,and complex gehetinite, whose unmatched thermal expansion coefficients result in the formation and easy spalling of the loose lay-er;in the transition layer,potassium oxide is the main hazardous substance which reacts with magnesia or spinel;the harmful substances in the quasi-original layer and the cold end are similar:a little potassium chloride and fluorine-containing compound;(3 )the potassium salt discovered in the whole depth of the used brick means the penetration ability of the potassium salt is ahead of the other substances;when the brick is cooled,the potassium salt induces the cracks,reducing the service life.
参考文献
| [1] | Liska M;Danek V .Computer calculation of the phase diagrams of sil-icate systems[J].Silik,1990,34(03):215-218. |
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