硫化焙烧法可较好地脱除锡铁精矿中锡,且可实现铁物相的预还原,有利于后续工艺中铁资源的高效回收。以热力学分析为基础,结合化学分析和X射线衍射分析,对锡铁精矿的硫化焙烧过程进行了研究。结果表明:无烟煤用量增加时,锡脱除率呈先增加后降低趋势,其添加量(无烟煤与锡铁精矿质量比)超过10%,部分锡物相被还原成金属锡,并与铁结合形成硬头,锡挥发脱除率下降;焙烧过程中铁物相由Fe3O4转变为FeO,实现了铁的预还原;以高硫煤对锡铁精矿进行还原-硫化复合焙烧,在氮气流量0.6 L/min、焙烧温度1 273 K、焙烧时间40 min和高硫煤(含硫量3.07%)添加量(高硫煤与锡铁精矿质量比)10%试验条件下,可将精矿含锡降至0.043%,该研究为高硫煤的清洁利用提供了一个新途径。
Tin can be removed effectively from tin-bearing iron concentrates with sulfidation roasting, and the iron phase is pre reduced, which are beneficial for the iron recovery. Based on the thermodynamic analysis, the process of tin removal was studied. The results show that tin removal rate increases first and then deceases with the increase of anthracite addition amounts (mass ratio of anthracite and tin-bearing iron concentrates). When the addition amounts increases over 10%, metallic tin and iron generate, and they combined forming hardhead, as a result of which the tin removal rate is reduced. Fe3O4 being reduced into FeO in the roasting process, pre-reduction of iron phase is realized. The tin content is decreased to 0.043%under the conditions of N2 flow rate 0.6 L/min, roasting temperature 1 273 K, holding time 40 min, and high-sulfur coal (S content of 3.07%) addition amount (mass ratio of high-sulfur coal and tin-bearing iron concentrates) 10%. This work supplies a new approach for the clean use of high-sulfur coal.