【作者】 李大纲；

【导师】 隋智通；

【作者基本信息】 东北大学 ， 冶金物理化学， 2005， 博士

【摘要】 我国赋含多元素复合矿，比较有代表性的是包头白云鄂博矿和攀枝花钒钛磁铁矿。由于这些复合矿的矿物组成复杂，嵌布粒度细小，属难选、难冶的矿产资源。含铁复合矿开发利用是以冶炼铁元素为主，综合回收其它有价元素。原矿中非铁金属元素绝大部分进入渣相，成为复合矿冶金炉渣。 含稀土高炉渣是包头白云鄂博含铁、稀土、铌和萤石的复合矿直接入高炉冶炼的中间产品。在冶炼过程中，铁、磷、铌等被还原进入铁基的金属相，而稀土几乎不能被还原，留在渣相。 含钛高炉渣，是冶炼钒钛磁铁矿产生的高炉渣。TiO₂约占23-25％，主要分布于钙钛矿、富钛透辉石和攀钛透辉石中。已有的工作表明：对该渣进行氧化改性处理，可使TiO₂富集于钙钛矿相，且钙钛矿相的晶粒度可达50微米，满足选矿分离的要求。本文基于选择性析出原理，研究了含稀土高炉渣中相的构成、铈钙硅石相析出长大和含钛高炉渣中钙钛矿相的单体解离。研究结果如下： 应用扫描电镜（SEM）观察并配合成分能谱分析（EDX）和X射线衍射（XRD）分析的方法，研究了含稀土高炉凝渣的相构成。结果表明：绝大部分的稀土在凝固过程中富集到铈钙硅石（RE₂O₃·CaO·2SiO₂）一相中。凝渣由铈钙硅石、枪晶石（CaF₂·3CaO·2SiO₂）、萤石（CaF₂）和硫化钙（CaS）四相构成。 应用“淬火法”并结合图像分析技术，研究了等温及非等温过程含稀土高炉渣中铈钙硅石相的结晶行为，并讨论了该相析出和长大的动力学规律。实验结果表明：铈钙硅石相的开始析出温度为1310℃；铈钙硅石相的析出、生长与冷却速度α有关，冷却速度小，粗化明显，有利于铈钙硅石相长大。当α=0.5℃／min时，体积分数可达20％，平均半径150-180μm。铈钙硅石相的等温和变温过程析出动力学分别服从JMA和JMAK经验方程。等温准平衡过程铈钙硅石相颗粒平均半径的立方与时间呈直线关系。 含钛高炉渣的氧化改性处理，改变了凝渣的相构成，凝渣由钙钛矿相、硅灰石相及尖晶石相构成。 适当氧化对高炉渣中钙钛矿相的析出、长大和单体解离有利，本文实验条件下，氧化处理4分钟、磨矿细度-38μm钙钛矿的单体解离度可达到72％左右。通过对钙钛矿相单体解离的分析，渣中钙钛矿相的解离以分散解离为主，提高钙钛矿相的粒度仍是首要任务。更多还原

【Abstract】 China is rich in multi-elements and complex mineral resources,such as Baiyue-Ebo deposit in Baotou and magnetite in Panzhihua representatively. Due to complexity and fine grains, it is very difficult to smelt and dress. In general, iron smelting from complex ore is main purpose with comprehensive utilizations of other valuable elements. The majority of value-nonferrous metals components in raw ores were concentrated in molten slag.The blast furnace slag bearing RE elements is the middle product which Baiyue-Ebo ore directly smelt. During smelting process , Fe、P and Nb components were reduced and poured into ferrous phase, but Rare Earths were not reduced and concentrated into slag.The blast furnace slag containing about 25%TiC>2 are produced by smelting V-Ti bearing magnetite. Ti components are dispersedly distributed in perovskite、 rich-titanium diopside and titanic pyroxene. It has been showed that Ti components were concentrated into perovskite phase by oxidization of molten slag.Base on "Selective precipitation" principle suggested by professor Sui, the precipitation and growth of calcium cerite phase in blast furnace slag bearing RE elements and the separation of perovskite phase in blast furnace slag bearing titanium was studied in this dissertation. The results as following:The morphology of the solidified blast furnace slag bearing RE elements was studied by means of SEM observation with the help of EDX qualitative analysis and XRD analysis. The experimental results show that the slag is consisted by calcium cerite （RE₂O₃·CaO·2SiO₂.）、cuspidine （CaF₂- 3CaO·2SiO₂）、 fluorite （CaF₂） and calcium sulfide （CaS） . During slow-cooling process, most rare earths elements in the slag are concentrated into one phase, which was identified as calcium cerite.The isothermal and the non-isothermal precipitation behavior of the calcium cerite phase in RE-bearing blast slag were studied by quenching method. And the kinetics of precipitate process and crystal growth of calcium cerite phase was also analyzed. The experimental results show that the nucleation and growth of calcium calcium cerite phase is related to cooling rate a, i.e. the lower cooling rate can更多还原