碱性全钒钛球团矿冶金性能试验及质量评价

Metallurgical performance test and quality evaluation of alkaline all-vanadium-titanium pellet

为充分利用钒钛矿资源,改善球团矿的性能并提高其在高炉中的占比,本文通过加入生石灰调节钒钛球团矿的碱度,研究碱性全钒钛球团矿的冶金性能,及其与碱度、膨润土配比、物相组成和微观结构的关系,并采用分层综合评价方法对球团矿的质量进行评价。结果表明:在预热温度为950℃,预热时间为20 min,焙烧温度为1230℃,焙烧时间为25 min的条件下,所得球团矿的抗压强度大部分高于2000 N/P,最大为3340 N/P;试样的RDI_(+3.15 mm)均高于96%;55%以上球团矿的RI高于70%,最高可达89.9%;自由膨胀指数均低于13%。分层综合评价结果显示,碱度为0.6、0.8和1.0的球团矿,当分别配入2.0%、1.5%和1.8%的膨润土后,综合性能最佳。综合考虑,建议生产球团矿的碱度为0.8,膨润土配比为1.5%。

In order to make full use of vanadium and titanium ore resources and improve the performance of pellets and increase their proportion in the blast furnace,the metallurgical properties of alkaline all-vanadium and titanium pellets and the its relationship with alkalinity,bentonite ratio,physical phase composition and microstructure are researched by adding quicklime to adjust the alkalinity of vanadium and titanium pellets,and the quality of pellets is evaluated by using a stratified comprehensive evaluation method.The results show that:under the conditions of preheating temperature of 950℃,preheating time of 20 min,roasting temperature of 1230℃ and roasting time of 25 min,the compressive strength of most obtained pellets is obove 2000 N/P and the maximum is 3340 N/P;the RDI_(+3.15 mm) of the specimens is higher than 96%.The RI of more than 55% pellet is higher than 70%,up to 89.9%;the free swelling index is all lower than 13%.The stratified comprehensive evaluation results show that the pellets with alkalinity of 0.6,0.8 and 1.0 have the best overall performance after adding 2.0%,1.5% and 1.8% bentonite,respectively.On balance,it is suggested that the alkalinity of pellets production should be 0.8 and the ratio of bentonite should be 1.5%.