贵州省岩风阡铝土矿床成因及成矿模型初探

岩风阡铝土矿是近年来在黔北地区新发现的大型铝土矿床。矿体多呈层状、似层状,赋存在上石炭统大竹园组(C_2d)中下部,产状稳定,厚度变化小。矿石具有碎屑、豆或鲕状、泥、粉晶结构和半土状、块状和致密块状构造等典型沉积组构。结合成矿物质来源、古成矿环境,表明岩风阡铝土矿为沉积型矿床。通过分析成矿过程,建立其成矿模式,认为广西运动使黔北地区上升为陆,韩家店组(S_1hj)页岩在湿热气候条件下,风化形成铝土矿"初始富集"的铁铝质古红土型风化壳,再经晚石炭世海侵作用,形成了含铝岩系的雏形。早—中二叠世的再次暴露,使"初始富集"的含铝岩系再次经历淋滤、富集,进而成矿。     

铝矾土化渣工艺的试验研究及应用

对转炉用新型化渣剂-铝矾土化渣工艺进行了试验研究,试验结果表明,其化渣效果可以替代萤石,改善了熔池反应的动力学条件,在保证转炉脱磷、脱硫能力的同时,减少了炉渣对炉衬的侵蚀和环境污染,降低了化渣剂成本。     

Kinetic Modelling of Different Bauxite Types in the Bayer Leaching Process

Abstract

The dissolution of aluminum hydroxides from bauxite ores constitutes a key process in the aluminum industry. Generally, aluminum minerals in bauxites are present in the form of gibbsite, boehmite or diaspore. Usually, these mineral forms are mixed in bauxite as a boehmite-diaspore or a gibbsite-boehmite mixture with different weight ratios. The Al₂O₃ recovery, as well as the kinetic parameters, during the Bayer leaching process of different bauxite types strongly depends on their mineralogical composition. In this paper an attempt was made to develop a mathematical model which enables calculation of the Al₂O₃ recovery from boehmite-diaspore or gibbsite-boehmite bauxite based on kinetic parameters available for leaching the “pure” bauxite types (containing only diaspore, boehmite or gibbsite as the main alumina bearing mineral form) and the mineral composition of the bauxite mixture.

Résumé

La dissolution des hydroxydes d'aluminium à partir de minéraux de bauxite constitue un procédé clé de l'industrie de l'aluminium. Généralement, les minéraux d'aluminium dans la bauxite sont présents sous forme d'hydrargillite, de boehmite ou de diaspore. Habituellement, ces formes minérales sont mélangées dans la bauxite en un mélange de boehmite-diaspore ou d'hydrargillite-boehmite, avec différents ratios en poids. La récupération de l'Al₂O₃, ainsi que les paramètres de la cinétique lors du procédé de lixiviation de Bayer de différents types de bauxite, dépend fortement de leur composition minéralogique. Dans ce document, on a essayé de développer le modèle mathématique qui rend possible le calcul de la récupération de l'Al₂O₃ à partir de bauxite de boehmite-diaspore ou d'hydrargilliteboehmite, basé sur les paramètres cinétiques disponibles pour la lixiviation des types “purs” de bauxite (contenant seulement du diaspore, de la boehmite ou de l'hydrargillite comme forme minérale principale porteuse d'alumine) et sur la composition minérale de la bauxite mélangée.     

以矾土碎矿和煤矸石合成莫来石均质料

采用Ⅰ等高铝矾土碎矿、Ⅱ等高铝矾土碎矿分别与煤矸石配合,并加入活性Al2O3调整m(Al2O3)/m(SiO2),按照矾土基莫来石均质熟料w(Al2O3)=68%～72%的要求,共配成6个混合料,将混合料湿磨至粒度≤0.044mm以均化化学成分,经成型、干燥后分别在1550℃、1600℃、1650℃和1700℃煅烧3h,冷却后测定其显气孔率和体积密度,以确定它们的烧结温度。结果表明:均质料的烧结温度为1700℃;在1700℃烧结制成的矾土基莫来石均质熟料的Al2O3含量为68%～72%,显气孔率<2.5%,体积密度≥2.75g·cm-3,其莫来石晶体发育良好,构成网络结构。同时,还将部分试样分别在800℃、1000℃、1200℃、1300℃、1400℃、1500℃、1600℃、1650℃和1700℃保温3h,测量其烧后线收缩率和显气孔率,并用XRD分析其相组成,据此分析试样在不同温度下所发生的反应。结果表明,试样在1000～1700℃加热过程中的变化可分为3个阶段:1000～1200℃的一次莫来石形成阶段,1200～1500℃的二次莫来石化阶段,以及1500～1700℃的液相烧结阶段。     

Post-mortem analysis of MgO–Al2O3–C bricks containing bauxite used in steel ladle walls

A serious problem with integrated masonry linings ladle was that the ladle wall bricks were difficult to be partially replaced. Thus, the service life of the ladle was determined by the properties of ladle wall bricks. In this study, the new generation of MgO–Al₂O₃–C bricks with bauxite aggregates was tested in a ladle lining of an integrated steel ladle for 103 cycles, and the corroded microstructure of the used brick was investigated. A multilayered structure of bauxite aggregates could be observed in the used brick, which inhibited the slag penetration along the boundary of the magnesia aggregates and reduced the degree of the aggregates fall off from the used bricks. Besides, during the process of slag penetration, bauxite aggregates could melt into the slag, which increased the viscosity of the slag and weakened the penetration ability of the slag. The MgO–Al₂O₃–C bricks with bauxite addition could improve the service life of the ladle to a certain extent.