转炉熔渣气化脱磷行为及矿相研究

Study on dephosphorization behavior and mineralogical phase of converter slag by gasification

针对转炉渣循环使用过程中的P元素富集问题,提出在溅渣护炉阶段利用还原剂气化脱除熔渣中的部分P元素。目前工业试验中熔渣气化脱磷率达到接近40%水平,为进一步提高熔渣脱磷率,对熔渣脱磷过程中不同相内P元素的变化规律进行了研究,进而为脱磷工艺操作提供理论指导和优化方向。利用SEM-EDS及XRD检测设备对转炉渣还原前后的矿相进行了分析,研究表明:转炉渣P元素主要富集在大直径颗粒状、板条状的2CaO·SiO_(2)、3CaO·SiO_(2)相中,电镜观测中这些微区内平均w(P)=2.4%,气化脱磷反应主要在这些富磷相中进行,反应后富磷相破裂变小,微区内平均w(P)=0.7%;转炉渣铁酸钙(CaO·Fe_(2)O_(3))相和RO相中的w(P)偏低,平均分布分别为1.1%和1.5%,此部分微区脱磷后两相混合,平均w(P)降低至0.27%;为进一步促进富磷相中的脱磷反应,应从动力学条件入手。

For the cyclic enrichment of P element in converter slag,it is proposed to use reducing agent to remove part of P element in molten slag in the stage of slag splashing.At present,the dephosphorization rate of slag gasification in industrial tests has reached a level of close to 40%.In order to further improve the dephosphorization rate of slag,the change law of P element in different phases in the process of slag dephosphorization was studied,and then the theoretical guidance and optimization direction for dephosphorization process operation were provided.The mineralogical phase before and after the reduction of converter slag were analyzed by SEM-EDS and XRD.The results show that the P element of converter slag is mainly enriched in 2CaO·SiO_(2) and 3CaO·SiO_(2) phase displayed in granular and lath.The average distribution of P element in this micro region observed by electron microscope is 2.4%.The gasification dephosphorization reaction is mainly carried out in these phosphorus rich phases,and the fracture of phosphorus rich phase becomes smaller after the reaction,the average mass fraction of P element in the micro area is 0.7%.The content of P in CaO·Fe_(2)O_(3) phase and RO phase of converter slag is low,and the average mass fraction is 1.1%and 1.5%respectively.After dephosphorization,the two phases are mixed,and the P mass fraction is reduced to 0.27%on average.In order to further promote the dephosphorization reaction in phosphorus rich phase,dynamic conditions need to be improved.