低品位硼铁矿有价组元强化迁移规律与分离理论研究

Aiming at low-grade ludwigite resources characteristics and the advantages and disadvantages of the existing separation technology in our country, and surrounding key scientific issues of the strengthening migration and separation of beneficial components in the process of comprehensive utilization of ludwigite resources, with improving the valuable components, such as Fe,B,Mg, recovery rate as our mission, the basic research on the strengthening migration rules and separation theories of beneficial components minerals in ludwigite are carried out by using the micro and the macro-scale experimental methods. The main research contents include: (1)The phase structure transition behaviour of valued components in the separation and extraction processes; (2)The interphase reaction kinetic law and influential factors in the hige-efficiency separation process of valuable components; (3)The strengthening and synergy of external fields on the transfer and separation of valuable components. Based on these studies, mineral sructural evolution and interphase migration rule of benificial components such as Fe,B,Mg in the heterogeneous complicated systems will be revealed and the synergy and strengthening mechanism between valuable components transfer and reaction processes in the field and molten salts conditions will be clarified. All the research above will enrich and perfect the strengthening migration rules and efficient separation theories of beneficial components and then propose new methods to improve their utilization ratio.This study will provide important theoretical and experimental support to strengthen higher efficiency and clean utilization of low-grade ludwigite.

本项目针对我国低品位硼铁矿资源特点和现有分离工艺的利弊，围绕低品位硼铁矿综合利用过程中有价组元强化迁移与高效分离的关键科学问题，以提高硼铁矿中铁、硼镁有价组元回收率为目标，开展从微观到宏观尺度的有价组元强化迁移规律及分离理论的基础研究，主要包括：（1）硼铁矿中有价组元高效分离提取过程的矿相演变规律；（2）有价组元高效分离提取过程的相间反应动力学；（3）外场对有价组元迁移与分离的强化与协同作用。在此基础上，揭示多相复杂体系中铁、硼、镁有价组元矿物结构演变规律和相间迁移规律，阐明外场及熔盐介质条件下有价组元传递与反应过程的协同强化机制，丰富和完善硼铁矿有价组元强化迁移规律和有效分离理论，提出旨在提高我国硼铁矿资源有价组元利用率的新方法，为我国低品位硼铁矿资源的清洁高效利用奠定理论和实验基础。

由于硼铁矿复杂的矿物组成和结构特点，现有传统的磨矿工艺在硼铁矿矿物磨细、有价组元有效解离过程中存在能耗高、效率低的弊端；硼铁矿矿物的分选产物硼精矿具有较低的活性，导致现有工艺难以清洁高效浸取硼元素。基于此，本项目着重对硼铁矿磨选矿工艺及其选分产物硼精矿浸取有价组元工艺进行优化，并且对这些过程中矿相演变规律、有价组元的分离强化迁移规律和界面化学反应演变规律进行了研究，通过引入微波场强化矿物的磨选和有价组元的浸取，通过焙烧过程添加钠盐使得钠化和活化同时进行，并且初步探讨了机械场对矿物活性的影响，同时通过矿物物理化学性质以及界面反应的变化探讨外场强化作用机制。主要结论为：（1）微波加热后硼铁矿表面产生许多宏观裂纹以至于破裂成很多小碎屑，矿石内部产生缺陷，裂纹的产生有利于矿石的磨细并且减少了细碎矿物过程中的能量消耗及机器的磨损。同时，采用难选矿石的微波预处理方法，有效强化了矿石磁性，利用后续硼铁矿的磁选分离，提高了硼铁矿的铁精矿品位和元素回收率。（2）采用微波能对硼精矿进行活化焙烧，可加快硼精矿的升温速率，在最优处理条件下，硼精矿的活性由64.68%提高至86.73%。微波焙烧有助于提高硼精矿的表面能，增大粉体的亲水性；同时，与传统焙烧相比，微波焙烧对硼精矿表面电性的影响更为显著，硼精矿微波条件下焙烧产物的ζ电位下降15.28mV~17.07mV，吸附OH-的能力明显增强。以Na2CO3、NaOH、NaOH-Na2CO3分别为钠化剂时，水浸两小时后，浸出率分别可达86.27%、89.83%、87.19%。钠化焙烧产物水浸滤液，通过加入盐酸调节pH至9左右，经过滤取出SiO2后，滤液再结晶克制的硼砂制品。（3）采用机械力场提高硼精矿活性，使硼精矿颗粒细化比表面积增大，同时形成晶格缺陷，降低表面化学键的稳定性，可以在短时间内将硼精矿的活性提高至89.47%。