高硅铁废渣直接还原铁晶粒形成与长大

 冶金工业每年会产生大量的高硅铁废渣,铜渣作为一种典型的高硅铁废渣,目前主要以露天堆积方式处理,为了提取铜渣中有价元素,并进行资源化利用,以某厂铜渣为例进行煤基直接还原试验,采用XRD衍射、扫描电镜等分析手段,探究铜渣在直接还原过程中不同阶段以及加入形核剂条件下铁晶粒的形成、长大及分布规律。结果表明,还原时间为30 min时,金属化率最高为78.40%,铁晶粒生长情况最为良好,铁元素分布最集中;还原过程中加入磁铁矿能明显提高金属化率,有利于铁晶粒的生长,当磁铁矿配比为20%时,金属化率最高,为87.59%;磁铁矿作为形核剂加入可降低形核位垒,促进铁晶粒的长大与铁元素的集中分布。

Formation and growth of iron grains in direct reduction process of high silicon and iron waste slag

A large amount of high silicon and iron waste slag was produced every year in the metallurgical industry. Copper slag is a typical high silicon and iron waste slag. Most of the copper slag has not been used effectively. In order to realize the extraction and resource utilization of valuable elements from copper slag, coal based direct reduction experiment was carried out. XRD diffraction, scanning electron microscopy and other testing methods were used. The effect of different stages and nucleating agent addition on the iron grain growth rule and distribution were investigated during the direct reduction of copper slag. The results show that when the reduction time was 30 min, the highest metallization rate was 78.40%, and the iron grain growth was the best, and the Fe element distribution was the most concentrated. Adding magnetite evidently increases the metallization rate in the reduction process. The highest metallization rate is 87.59% when the magnetite proportion ratio is 20%. The addition of nucleating agent magnetite reduced the nucleating barrier and promoted the Fe element concentration.