回转窑内氧化球团物料对耐火材料侵蚀行为的研究

Research on erosion behavior of oxide pellets materials on refractory in rotary kiln

氧化球团回转窑内结圈的形成对耐火材料造成蚀损,本文在实验室模拟现场条件,从铁元素渗透角度研究侵蚀料成分在不同条件下对耐材的侵蚀作用,研究结果表明:含高SiO_2和碱金属的侵蚀料会促进对耐火材料的侵蚀渗透,侵蚀料中SiO_2含量的增加会促进二次莫来石的形成,导致体积膨胀,从而加剧耐材侵蚀及结构破坏,碱金属会促使低熔点物质的形成,并在高温下形成导致体积膨胀的霞石类矿物,破坏耐火材料结构;随着连续高温保持时间的延长,侵蚀料对耐火材料的侵蚀程度加深。建议在采用回转窑工艺生产氧化球团过程中,应尽量采用低硅低碱金属的铁精矿,减少粘结剂膨润土的配加量;采用间歇降温操作,一方面利于减缓结圈物对耐火材料的侵蚀,一方面有助于结圈物的脱落。

Erosion of refractories occurs by ring formation in rotary kiln for oxidized pellets. In this paper, erosion effects of deposits to refractories under different compositions were studied on the view of iron penetration, by monitoring the site conditions in lab. The results show that ： deposits with high contents of SiO2 and alkalis are conductive to the iron penetration to refractory, where SiO2 promotes the formation of secondary mullite, low melting temperature and nepheline materials are accelerated by alkalis, leading to the volume expansion and structural damage of refractory; deeper erosion happens by prolonging holding duration at continuous high temperature. Adviees were proposed to using iron concentrates with low SiO2 and alkalis, reducing the bentonite dosage during production of oxidized pellets by grate-kiln process, and taking intermittent cooling operation to slow clown the erosion of ring to refractory and contribute to the fall off of ring.