白云鄂博矿铌物相转化与成核生长研究

Study on Phase Transformation and Nucleation Growth of Bayan Obo Niobium Ore

对白云鄂博矿中铌矿物相的高温熔融矿相转化和成核生长行为进行了研究,着重考察了不同的梯度保温机制、碱度(CaO/SiO_(2))以及NaF、CaF_(2)、P_(2)O_(5)等熔渣改性剂对物相转化与成核生长的影响。结果表明:1400℃以上的熔化温度,以及1300℃以下的析晶温度,是高品位铌矿相转化的关键;控制碱度在1.0~1.3之间,有利于形成单一高品位铌相和晶粒的生长;2%左右的NaF添加或2%~5%范围的CaF 2添加有利于提高富铌相的Nb_(2)O_(5)品位和富铌相的晶粒粗化;P_(2)O_(5)虽然有利于铌向单一高品位铌矿物相转化,但过多的P_(2)O_(5)引入,会导致铌相晶粒的急剧细化。

The phase transformation and nucleation growth behavior of niobium mineral phase in Bayan Obo mine under high temperature melting state were studied.The effects of different temperature mechanism,basicity(CaO/SiO_(2))and slag modifiers such as NaF,CaF_(2) and P_(2)O_(5) on phase transformation and nucleation growth were emphatically investigated.The results show that the melting temperature above 1400℃and the crystallization temperature below 1300℃ are the key to the phase conversion of high-grade niobium ore.Control alkalinity between 1.0 and 1.3 is beneficial to the formation of single high-grade niobium phase and the growth of grain.The addition of about 2% NaF or 2%-5%CaF_(2) can improve the grade of Nb_(2)O_(5) and grain coarsening of niobium-rich phase.Although P_(2)O_(5) is conducive to the transformation of niobium into a single high-grade niobium mineral phase,excessive P_(2)O_(5) will lead to sharp refinement of niobium phase grains.