碱度变化对电炉渣含铁组分回收率的影响规律

 电炉渣相对于转炉渣具有更多的高温余热和更低的含铁组分回收率，但目前还没有合适的处理方法利用其余热回收更多的含铁物质。试验以河沙为改质剂，采用熔态改质方法处理电炉渣，研究在不同改质剂掺量下电炉渣碱度变化对其含铁组分回收率的影响规律，并进一步采用XRD、SEM-EDS等手段分析其中的矿相和结构变化。研究表明，采用熔态改质方法，在电炉熔渣排渣过程中加入改质剂降低其碱度，不仅能够充分利用其余热，还能够提高熔渣固化后的铁质组分回收率和胶凝活性，是电炉渣排渣处理的一条新途径。当改质电炉渣碱度下降到1.6时，随着SiO2的增加，以三价铁形式存在的Ca2Fe2O5和以二价铁形式存在的RO相减少并消失，活性矿物Ca2SiO4和强磁性的MgFe2O4、Fe3O4、FeCr2O4等形成并增加，这有利于铁及铬、锰重金属的回收以及尾渣胶凝活性的提高。在碱度为1.3时，强磁性矿物数量和磁选物质含铁组分回收率达到最大值69.71%，铁品位提高了43.74%。当改质电炉渣碱度小于1.3时，磁性矿相逐渐转变为弱磁性的含铝尖晶石，铁组分回收率下降。

Effects of EAF slag basicity on its recovery rate of iron components

Compared with BOF slag,EAF slag has larger amount of higher-temperature waste heat lower recovery rate of iron components,but there is no suitable treatment method for EAF slag at present. In the current study,EAF slag was disposed by hot modification method with sands as modifier,and the effects of EAF slag basicity on recovery rate of iron components were studied using XRD and SEM-EDS methods to study the change of mineral phase and structure. Results showed that hot slag modification is a new method for EAF slag to not only utilize its waste heat,but also im-prove its cementitious properties and recover more iron components. When the basicity of modified EAF slag decreased to 1.6,Ca2Fe2O5(the presence of ferric iron)and RO(the presence of divalent iron)reduced and even disappeared,ce-mentitious mineral,Ca2SiO4 and some strong magnetic phase(such as MgFe2O4,Fe3O4,and FeCr2O4)generated and in-creased gradually,which would contributed to the improvement of its cementitious properties and recovery rate of iron components. When basicity of modified slag was 1.3,the total amount of magnetic phase and recovery rate of iron com-ponents reached a maximum of 69.71%and its iron grade increased by 43.74%. When the basicity of modified slag was less than 1.3,Fe3O4 gradually transformed to weak magnetic phase(such as aluminum spinel),and the recovery rate of iron components thereby decreased.