硫酸渣直接还原焙烧提铁降硫影响因素研究

对硫酸渣直接还原过程中脱硫剂的种类与用量、焙烧温度、不同升温方式、焙烧时间等因素对焙烧过程的影响进行了研究。确定的最佳工艺条件为: 还原剂用量为30%, 脱硫剂SH用量为15%, 随炉升温, 焙烧温度为1 200 ℃, 焙烧时间为60 min。在此条件下可得到铁品位为90.13%、铁回收率为95.06%、硫含量为0.040%的还原铁。X射线衍射和扫描电镜分析结果表明, 硫酸渣中的硫与脱硫剂反应生成了硫化钙, 且焙烧温度的升高和随炉升温都有利于硫化钙的生成; 通过磨矿-磁选方法可将硫化钙与金属铁分离, 从而达到脱硫目标。

Study on Influencing Factors for Increasing Iron Grade and Reducing Sulfuric Content by Direct Reduction Roasting with Sulfur Acid Residues

The effects of types and dosages of desulfurizer, roasting temperature, heating ways and roasting time on roasting during direct reduction process with sulfur acid residues were studied. Under the following optimum process conditions: with the dosage of reductant being 30%, dosage of the desulfurizer SH being 15%, temperature increased with that of the furnace, 60 mins for roasting at a temperature of 1 200 ℃, the direct reducted iron can be obtained at a grade of 90.13%, with recovery of 95.06% and sulfur content of 0.040%. The X-ray diffraction and SEM analysis showed that the sulfur in sulfur acid residues reacted with desulfurizer to generate calcium sulfide, which also benefits from an increase in roasting temperature and furnace temperature. The generated calcium sulfide can be separated from metallic iron by grinding-magnetic separation process for desulfurization.