铁铝复合矿中非铁元素分离与提取新工艺的基础研究

With the rapid development of the metallurgical industry of our country, the serious shortage of domestic high-quality iron and aluminum resources has become a bottleneck constraining the sustainable development of steel and aluminum industry. However, a reserve of more than 2 billion tons of low grade Fe-Al complex ores with multi-metal intergrowth has not yet been developed and utilized due to the lack of effective technologies. Thus, it is imperative and of great significance to carry out the basic research on the efficient utilization of Fe-Al complex resources. This project aims to create mineralogical conditions for the effective downstream separation by regulating the performance of various constituents resulted from the synergistic effect of additives and solid state reduction roasting, based on the study of process mineralogy of Guangxi high-iron gibbsite bauxite. In order to found the theoretical foundation and technical prototype of components performance regulation - efficient separation of Fe-Al complex ores, the transformation and performance regulation mechanisms among iron, aluminum, silicon and associated elements such as gallium, vanadium, titanium, rare earth during the solid state reduction in the presence of additives, as well as the separation methods are primarily to be investigated by using multi-disciplinary theories and methods along with various micro-testing technologies. It is believed that new theories and methods for the efficient utilization of high-alumina iron ores, high-iron bauxite and alumina red mud will be founded, which would provide technical support for the sustainable and healthy development of China's steel and aluminum industry.

随着我国冶金工业的快速发展，铁、铝矿石短缺的矛盾日益突出，已成为制约我国钢铁和铝工业持续发展的瓶颈。与此同时，我国储量超过20亿吨的低品位、多元素共生铁铝复合资源因缺乏经济有效技术尚未开发利用。要实现此类资源的合理利用必须突破其共生非铁元素的回收问题，开展铁铝复合资源中非铁元素高效分离提取的研究意义重大。本项目以广西高铁三水铝石型铝土矿为对象，以全元素回收利用为目标，以创造高效分离提取的矿物学条件为途径，提出了基于固态还原和添加剂协同作用的组分性能定向转化和调控学术思路。综合运用多学科的原理与方法，重点研究还原与添加剂协同作用下，铁与铝、硅及伴生元素镓、钒、钛、稀土等的物相转化规律、调控机制及分离提取方法，建立铁铝复合矿组分性能调控-高效分离提取的理论基础，构建相应的技术原型，为铝铁复合资源的高效利用提供新理论和新方法，为我国钢铁和铝工业的持续健康发展提供技术支撑。

开展铁铝复合资源中非铁元素高效分离提取的研究，对缓解我国冶金工业铁、铝矿石短缺的矛盾意义重大。本项目以广西高铁三水铝石型铝土矿、赤泥等铁铝复合资源为对象，以全元素回收利用为目标，主要完成了以下几方面工作：（1）建立了添加剂作用下还原焙烧过程中各组分物相转化的热力学基础，揭示了铁铝复合资源中铁与非铁组分高效分离的内在原因；（2）查明了还原焙烧过程中铁、铝、硅等主要组分的物相转化规律及调控机制，探明了添加剂在还原焙烧过程中的作用机理；（3）确定了铁、铝等物相和组分的行为与分离方法，建立了钠化还原焙烧-磁选分离亲铁与非铁元素的适宜条件；（4）探明了富铁产物中镓及非铁产物中铝、硅等主要组分的溶解析出行为及分离回收方法。（5）查明了铁铝复合资源中钛和稀土组分的富集、溶解行为，确立了钛和稀土元素分离回收方法。.焙烧过程中，钠盐会与Al2O3、SiO2优先反应生成各种铝硅酸钠，有效避免了FeO•SiO2的生成，从而有利于铁铝复合资源中铁与非铁组分的高效分离。在Na2CO3用量25%、Na2SO4用量15%、硼砂用量2%、焙烧时间60mim、焙烧温度1050℃、磨矿细度-200目90%，磁场强度975Gs的条件下，直接还原铁粉全铁品位及回收率均达90%以上。镓几乎全部进入富铁产物中，采用NaOH碱法溶出可回收60%镓。酸法/碱法均可回收非铁产物中铝，采用30wt.%硫酸浸出，非铁产物中Al2O3、SiO2和Na2O浸出率分别达到88.34%、90.25%和96.62%，浸出液经活性炭吸附-结晶实现了硅、铝、钠的分步提取。采用27wt.%NaOH溶液高温碱浸，溶出温度200℃，非铁产物中铝相对溶出率达98%。赤泥经钠化还原焙烧-磷酸浸出-NaOH碱浸等分步处理后，钛及稀土一直定向富集在浸出渣中，总体回收率高达85%，经高浓度磷酸浸出，稀土浸出率高达90%左右，98%以上钛保留在浸出渣中。稀土浸出液经P204萃取-NaOH反萃，95%以上钪被有效萃出，且与有害杂质分离效果良好。.本项目突破了传统选矿、冶金工艺路线只考虑铁和/或铝回收的限制，实现了铁、铝、硅、镓和稀土等全元素的分离富集与综合回收，建立了铁铝复合资源中各组分高效分离提取的理论基础，构建了铁铝复合资源全元素利用的技术原型，为我国钢铁工业和铝工业的持续、健康发展提供了技术支撑。