酸溶-浮选-水解法分步回收拜耳法赤泥铁铝钛金属组元机制

To realize selective separation and recycling of valuable components, it is very significant to conduct the fundamental investigation on recycling and utilization of metal components in red mud, which will promote the harmonious development of non-ferrous metal industry. Aimed at same scientific issues of separation of elements in Bayer red mud, the study on mechanism of stepwise recycling of Fe, Al and Ti based on acid extration-flotation-hydrolysis process is carried out in this project. The key science problem of controllable releasing and stepwise recycling of metal components is the controlling degree of molecular behavior and dynamics metal ions during the process of beneficiation and extractive hydrometallurgy. Based on technical superiority of the existing reagents and techniques, the main contents are mainly included as follows: (1) the dissolving and releasing behaviors of metal components in red mud under the acidic ionic liquid leaching system, and the stable controlling mechanism based on solution chemistry; (2) molecular behaviors of selective oriented transformation of the dissolved metal components-chelating agents, and the static stability controlling of properties of flotation targeted particles under the flotation system; (3) the dynamic stability controlling and strengthening mechanism of particle flowing separation process in flotation targeted particles under the flotation system; (4) enhancing chemical stabilization of chemical environment and controlling product properties of dissolved metal components in hydrolysis reaction system. This project will provide the supports for the development of acid extration-flotation-hydrolysis technology of metal components in red mud, and the foundation of a theory and method for the full cycling of red mud.

开展赤泥中宏量金属组元选择性分离与回收基础研究，实现有价组分资源化利用，对有色金属工业和谐发展意义重大。针对拜耳法赤泥中物质/元素分离过程共性科学问题，本项目提出开展酸浸-浮选-水解法高效分离与分步回收铁铝钛机制的研究。金属组元分步回收能否成功的关键在于分离过程分子行为与动力学调控程度。依托现有药剂与技术优势，本项目围绕如下内容进行研究：（1）酸性离子液体浸出体系下赤泥金属组元的溶解释放行为及其溶液化学稳定调控机制；（2）浮选体系下溶解态金属组元-螯合药剂选择性定向转化的分子行为及其浮选靶点颗粒产物性质静态稳定性调控；（3）浮选体系下金属组元浮选靶点颗粒流动-分离过程的动态稳定性调控与强化机制；（4）水解反应体系下溶解态金属组元化学环境稳定强化及产物性质调控。本项目成功实施，将为建立基于酸溶-浮选-水解法的赤泥有价组分高效分离技术原型奠定基础，为实现大宗赤泥的资源化利用提供理论与技术支撑。

赤泥具有碱性高、粒度细、组成复杂等特点，综合利用难度大。赤泥中含有大量的有价金属钛、铁、铝元素，开展赤泥中金属组元的高效分离回收技术研究具有十分重要的意义。本研究针对拜耳法赤泥中物质/元素分离过程共性科学问题，开展了酸浸-浮选-水解法高效分离与分步回收铁铝钛机制的研究。研究内容如下：酸浸体系下赤泥金属组元的溶解释放行为及其溶液化学稳定调控机制；浮选体系下溶解态金属组元-螯合药剂选择性定向转化的分子行为及其浮选靶点颗粒产物性质静态稳定性调控；浮选体系下金属组元浮选靶点颗粒流动-分离过程的动态稳定性调控与强化机制；水解反应体系下溶解态金属组元化学环境稳定强化及产物性质调控。研究结果表明在最优浸出工艺条件下，赤泥中钛、铁和铝的浸出率分别为64.32%、52.43%和93.65%。浸出动力学研究表明，钛和铁的浸出过程表观活化能为48.64 kJ/mol和46.84 kJ/mol，符合化学反应控制模型；铝的浸出过程表观活化能为4.049 kJ/mol，符合扩散控制模型。浮选体系中以N-亚硝基苯胲胺为金属离子螯合剂，螯合剂投加量为14 mmol/L，反应时间为30 min，反应温度为30℃，溶液pH值为1，钛铁的螯合沉淀率分别为99.98%和99.79%，铝的螯合沉淀率仅为5.62%。以CTAB为表面活性剂，溶液pH为1.0，CTAB投加量为1.5 mg/L，钛和铁浮选去除率高达99.89%和99.96%，铝浮选去除率仅为3.43%。浮选螯合过程机理表明，螯合剂中的吸附位点可与钛铁离子同时发生螯合反应生成不规则的絮体，随着螯合剂投加量的增加，螯合沉淀颗粒的平均粒径逐渐增大，利于浮选分离。水解反应体系中还原剂的加入可以促进两种金属组元的水解分离，在溶液pH值为3，反应温度为20℃，反应时间为1h，钛铁分离回收效果良好。本研究为建立基于酸溶-浮选-水解法的赤泥有价组分高效分离技术原型奠定了基础，为实现大宗赤泥的资源化利用提供了理论与技术支撑。

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