Z.Z. Guo
,
T.P. Lou
,
L. Zhang
,
L.N. Zhang
,
Z.T. Sui
金属学报(英文版)
The effects of transformation of slag composition and additive agents on the morphology, the precipitation behavior, the crystal growth, and the volume fraction (VF) of perovskite (CaO·TiO2)crystal in the Ti-bearing blast furnace slags were investigated.
As the morphology of perovskite is dispersed in molten slags, the crystal growth mechanism of the melting of fine dendrites and the
coarsening of large grains exist throughout the solidification of molten slags. With the increase of CaO and Fe2O3 content, VF of
perovskite obviously increases. However, high basicity leads to the viscosity of slag, which results in the reduction of the
average equivalent diameter (AED). The experimental results showed that the presence of the additives CaF2 and MnO efficiently
decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promoted its growth.
关键词:
perovskite phase
,
null
李军成
,
郭占成
,
高金涛
稀有金属
doi:10.13373/j.cnki.cjrm.2014.01.014
含钛高炉渣中富钛相因其分散在炉渣的多种矿相中且晶粒细小,常规选矿分离技术难以将富钛相从含钛高炉渣中有效地分离出来.将超重力场引入到CaO-TiO2-SiO2-Al2 O3-MgO熔体,为了在冷却过程中钙钛矿相定向富集,重点探讨了熔体中钙钛矿相在不同重力系数及冷却速率下富集规律.研究结果表明当CaO-TiO2-SiO2-Al2 O3-MgO熔体以v=5K·min-冷却速率在重力系数G≥750进行富集后,试样沿着超重力方向出现明显分层且试样中钙钛矿相沿着超重力方向呈现粒度梯度分布.对分层的试样纵剖后进行光学显微镜观察,熔体中的钙钛矿相在超重力作用下全部富集到试样的中下部区域,而在试样上部区域没有发现钙钛矿晶粒.对本实验条件下熔体中钙钛矿相运动机制进行分析,熔体中钙钛矿晶粒的运动速度与晶粒直径的平方成正比,熔体中大粒径的钙钛矿晶粒比小颗粒晶体在相同的重力系数下具有更大的运动速度,最终富集到试样的底部,而细小的钙钛矿晶粒则富集到式样的中部.假设熔体中的钛以TiO2形式存在,当CaO-TiO2-SiO2-Al2 O3-MgO熔体以v=5 K·min-1冷却速率在重力系数G=750时进行富集后,富集到试样中下部精矿中的TiO2质量分数可达34.8％,而尾矿中TiO2质量分数仅为11.28％.考虑到常重力试样中TiO2质量分数为22.34％,通过离心富集后,精矿中钛的回收率高达77.13％.
关键词:
离心富集
,
超重力
,
钙钛矿相
,
含钛高炉渣
