Although the total amount of boron resources in China is high, the grades of these resources are low. The authors have already proposed a new comprehensive utilization process of boron-bearing iron concentrate based on the iron nugget process. The present work describes a further optimization of the conditions used in the previous study. The effects of CaO on the reduction–melting behavior and properties of the boron-rich slag are presented. CaO improved the reduction of boron-bearing iron concentrate/carbon composite pellets when its content was less than 1wt%. Melting separation of the composite pellets became difficult with the CaO content increased. The sulfur content of the iron nugget gradually decreased from 0.16wt% to 0.046wt% as the CaO content of the pellets increased from 1wt% to 5wt%. CaO negatively affected the iron yield and boron extraction efficiency of the boron-rich slag. The mineral phase evolution of the boron-rich slag during the reduction–melting separation of the composite pellets with added CaO was also deduced.
基于转底炉直接还原工艺,对以碱化甘蔗渣作为黏结剂的含碳球团冷态成型工艺进行探究.首先通过单因素试验考察碱化时间、碱化温度、NaOH质量浓度以及造球压力对球团机械强度的影响.然后采用正交试验方法,确定影响碱化蔗渣黏结性能的这几个因素的主次顺序,得出最佳工艺参数.实验结果对比后发现:含碳球团的机械强度均随着各单因素水平值的上升先增大后减小.通过正交试验获得了较适宜的工艺参数为,NaOH质量浓度为9%,碱化温度为105℃,碱化时间为4 h,造球压力为15 MPa.此时含碳球团的落下强度与抗压强度能达到22.6次/0.5 m和79.3 N.
