磁化焙烧过程中铁矿物的物相转化及调控机制

Iron ore resources are the major strategic needs of the country, and it is significant to achieve the efficient exploitation and utilization of domestic iron ore resource. Magnetization roasting is the most effective technology for the efficient exploitation and utilization of refractory iron ore resources. However, the magnetization roasting of refractory iron ores is a non-equilibrium process coupling of various iron minerals magnetization. Plenty of problems still exist, for example, the accurate control of iron phase transformation, the uneven quality of roasted ore and the high production costs. This project will focus on the issue of phase transformation and controllable mechanism of iron minerals in magnetization roasting process and carry out related fundamental research. Firstly, the research will systematically study the physical and chemical reaction behaviors of magnetization roasting process under single and multiple iron minerals system, elaborate the thermodynamics and kinetics of magnetization roasting reaction, and find out the interaction laws of multiple iron minerals reaction. Then, further study of crystal formation and growth mechanism of magnetite and maghemite will be carried out, which will reveal the microcosmic mechanisms and growth laws of magnetite and maghemite crystal, and construct the growth kinetic model of crystal. Finally, to achieve the accurate coordination controllable mechanism of iron phase transformation, the theoretical system of iron phase transformation of refractory iron ore in the magnetization roasting process will be established. And the expected results of ferromagnetic minerals conversion rate > 95%, iron concentrate grade > 65% and iron concentrate recovery > 90% will be obtained. This research will provide the theoretical foundation for the further development of the magnetization roasting technology.

铁矿资源属于国家重大战略需求，实现我国铁矿资源的高效开发利用具有重要意义。磁化焙烧是实现复杂难选铁矿资源高效开发利用最有效技术。然而，复杂难选铁矿石磁化焙烧是一个多种铁矿物磁化反应耦合的非均衡过程，铁矿物物相转化难以精准调控，焙烧矿质量不均匀、生产成本高等问题依然存在。本项目紧密围绕磁化焙烧过程中铁矿物物相转化和调控开展基础研究工作，首先系统研究单一和多元铁矿物体系磁化焙烧过程中物理化学反应行为，阐明铁矿物磁化反应热力学和动力学机制，探明铁矿物反应交互影响规律；进一步深入研究磁铁矿和磁赤铁矿晶体的形成和生长机理，揭示磁铁矿和磁赤铁矿晶体形成微观机理和生长规律，构建晶体生长动力学模型；最后建立难选铁矿石磁化焙烧物相转化调控理论体系，实现铁物相精准协调控制，获得强磁性矿物转化率>95%、铁精矿品位>65%、铁回收率>90%的指标，为推动磁化焙烧技术的进一步发展奠定理论基础。

我国铁矿资源储量丰富，但具有品位低、结晶粒度细、矿物组成复杂的特点，开发利用难度大。磁化焙烧是处理复杂难选铁矿最为行之有效的方法之一。然而铁矿石磁化焙烧过程中铁矿物物相转化难以精准控制，常造成产品质量不均匀、生产成本高、碳排放量大等问题，严重制约着磁化焙烧技术的大规模工业化应用。本项目紧密围绕复杂难选铁矿石磁化焙烧过程中铁矿物物相转化精准控制这一关键科学问题开展基础研究。.项目以赤铁矿、褐铁矿、菱铁矿为研究对象，针对单一和多元铁矿物体系磁化焙烧反应进行热力学模拟计算。开展了单一和多元铁矿物体系磁化焙烧反应动力学研究，建立了铁矿物磁化焙烧动力学模型，确定了反应过程的限制性环节。深入研究了铁矿石磁化焙烧过程中物相和微观结构的演变规律，揭示了菱铁矿分解、褐铁矿脱羟基和赤铁矿磁化还原之间的交互影响规律。发现了菱铁矿热分解反应释放出CO可以充当赤、褐铁矿磁化焙烧的还原剂，褐铁矿脱水产生的微观孔隙有利于与还原气反应生成磁铁矿。建立了磁铁矿晶体粒度测量与表征方法，构建了磁铁矿晶体生长动力学模型。查明了铁矿物晶体和表面结构物理化学性质，研究了气体还原剂CO在铁矿物表面吸附和反应过程。构建了新生磁铁矿氧化机理模型，提出了新生磁铁矿冷却氧化工艺。形成了难选铁矿石磁化焙烧物相转化调控技术，针对典型难选铁矿石，获得了磁选精矿铁品位大于65%、铁回收率大于90%的指标。.本项目建立了复杂多元铁矿物磁化焙烧体系中物相转化过程强化及调控技术理论体系，解决了磁化焙烧过程中物相精准控制这一核心问题，为难选铁矿资源磁化焙烧高效分选奠定理论基础。研究成果获辽宁省技术发明一等奖1项；出版国家出版基金资助专著1部；发表学术论文27篇，其中SCI收录19篇；授权国家发明专利12项；培养了优秀青年科学基金获得者1人，兴辽英才计划青年拔尖人才1人，博士、硕士研究生11人。