烧结法赤泥的物质组成与颗粒特征研究

运用X射线荧光光谱仪、电感耦合等离子体质谱仪、X射线粉晶衍射仪(XRD)、透射电子显微镜和激光粒度分析仪等手段,对贵州烧结法赤泥主量元素和微量元素的化学组成、物质组成、微观形态和粒度分布等基本特征进行系统研究,并将烧结法赤泥的组成与拜耳法赤泥进行对比。结果表明,烧结法赤泥的主要化学成分是CaO、Al2O3、SiO2、Fe2O3、TiO2、Na2O、K2O和MgO,与拜耳法赤泥相比具有高钙低铝的特征。透射电子显微镜分析烧结法赤泥中部分矿物的颗粒形态与特征,XRD分析其主要物相有硅酸二钙、铝酸三钙、方解石、钙钛矿等,还有少量分散的含铁矿物、黏土类铝硅酸矿物。根据微观形态的不同,将烧结法赤泥的组成矿物划分为三类:薄片状或者大块状聚集体;片状、柱状、颗粒状等规则形态;毛发状、细丝状聚集体。通过激光粒度分析仪测量烧结法赤泥的粒径分布情况,表明粒径细小是赤泥的重要特征,同时也是影响赤泥在选矿等领域综合利用的重要因素之一。通过对赤泥物相组成与粒度特征的综合分析,为烧结法赤泥综合利用提供了必要的基础资料和科学依据。

Study on Material Composition and Particles Characteristics of Red Mud from the Sintering Alumina Process

Red mud can be derived from the processing of bauxite using different methods. The chemical composition of red mud varies greatly with respect to the types of bauxite ore and processing parameters. The characterization of red mud with sintering alumina process from Guizhou, China, was investigated using X-ray Fluorescence Spectrometry (XRF), Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Malvern Mastersizer 2000 laser scattering particle size distribution analyzer in this study. The results show that red mud consists of eight main chemical compositions of CaO, Al₂O₃, SiO₂, Fe₂O₃, TiO₂, Na₂O, K₂O and MgO, and multiple trace elements. Calcium silicate, tricalcium aluminate, perovskite, calcite, amorphous mass and other phases such as iron-bearing minerals and clay minerals were identified in red mud by XRD. TEM analysis showed that mineral phases in Guizhou red mud used in this paper had different micro shapes: thin sheets and aggregation of small particles; regular shapes such as flake, column, and grain; aggregation of filamentous or trichoid shapes. The small size of red mud particles related to comprehensive utilization of red mud and was one of its distinctive characteristics or attributes revealed by a Mastersizer 2000 laser scattering particle size distribution analyzer. The purpose of this investigation is to establish the relationship between the properties of red mud from sintering alumina process and its usage, so as to provide necessary data and a scientific base for its comprehensive utilization.