风化壳淋积型稀土矿浸取过程离子的运移机理

The weathered crust elution-deposited rare earth ore is rich in the middle and heavy rare earth with great commercial value, so its exploitation has been paid wide attention of the world. However, the lack of the ion migration mechanism in the leaching process of weathered crust elution-deposited rare earth ore cause the low leaching efficiency of RE, the high content of impurities and the large consumption of leaching agent. Therefore, based on the previous research, the mineralogy properties of the different ore sample of the weathered crust elution-deposited rare earth ore will be analyzed by the modern analysis and testing technology to obtain the technological mineralogy characteristics of ores. Using the method of column leaching, the effect of the fluid properties on the migration mechanism of rare earth, aluminum and ammonium in the uniform rare earth ore samples will be discussed to explore the equilibrium relationship among ions, and the variation law of ions concentration with the depth of ore samples. Using continuous packing column to simulate the real weathered crust orebody, the effect of the ore properties on the migration mechanism of rare earth, aluminum and ammonium in the weathered crust orebody will be discussed to explore the key factors that affect the migration characteristics of ions, and the variation law of ions concentration. It will benefit to clarify the migration mechanism of ion in the weathered crust orebody, and reveal the leaching mechanism of rare earth and impurities, and the migration mechanism of ammonium ions. This research will optimize the leaching process, improve the leaching efficiency of rare earth, deepen the theoretical basis of weathered crust elution-deposited rare earth ores and provide the theoretical guidance for the exploitation of the rare earth ores with high efficiency, little impurities and low consumption.

风化壳淋积型稀土矿因富含具有巨大商业价值的中重稀土，其开发利用受到全球的广泛关注，但由于风化壳淋积型稀土矿浸取过程中离子运移机理的薄弱，导致稀土浸出率低、杂质含量高和浸取剂消耗大，造成宝贵稀土资源的浪费。因此，本项目在前期研究基础上，拟借助现代分析测试技术分析风化壳淋积型稀土矿不同深度矿样的工艺矿物学，获得矿石的工艺矿物学特征；采用柱浸方式，探索流体性质影响稀土、杂质铝和铵等离子在均匀稀土矿样中的运移过程，探寻离子之间的平衡关系及其浓度随矿石深度的变化规律；利用连续装柱模拟真实风化壳矿体，考察矿石性质对稀土、杂质铝和铵等离子在风化壳矿体中运移特性的影响，探究影响离子运移特性的关键因素和离子浓度的变化规律，阐明离子在风化壳矿体中的运移规律，揭示稀土和杂质的浸出机理和铵根离子的运移规律，优化浸出工艺，提高稀土的浸出率，可深化风化壳淋积型稀土矿的理论基础，为其高效低杂低耗地开采提供理论指导。

风化壳淋积型稀土矿开采过程中，常存在稀土浸出率低、杂质含量高和浸取剂消耗大等问题，造成宝贵稀土资源的浪费。本项目借助现代分析测试技术，探讨了风化壳淋积型稀土矿的工艺矿物学，获得了矿石的工艺矿物学特征，揭示了工艺矿物学规律。原矿和浸出尾矿的扫描电镜图、热重曲线和红外光谱图均基本相同，说明稀土的浸出只是铵根离子与稀土离子之间的离子交换作用。.采用柱浸方式，考察了稀土、铝离子及铵根离子在风化壳淋积型稀土矿浸出过程中的运移规律，发现随稀土矿高度的增加，峰形变宽，保留体积增大，峰值浓度增大，峰面积越大。随着液固比的增大，靠物理作用吸附于黏土矿物上的铵不断减少，而通过离子交换吸附的铵则逐渐增多，即被离子交换下来的稀土和铝的量增多，直至平衡，但黏土矿物对铵的吸附总量却始终约为0.61-0.63 mg/g。尾洗水较难将黏土矿物中的化学吸附铵解析下来。稀土和铝的浸出规律基本相同，但铝的浸出要稍晚于稀土。该结果可深化风化壳淋积型稀土矿的理论基础，为其高效低杂低耗地开采提供理论指导。.根据稀土、杂质和铵根离子的流出规律，可将从矿土底部流出的稀土浸出液分两次收集。当稀土浸出液的体积与浸取剂的体积相同时或当流出的稀土浸出液浓度经一最大值后降低至0.5 g/L以下时，此为第一次收集。后继续收集直至不再有稀土浸出液流出，此为第二次收集。对第一次收集的稀土浸出液进行除杂和沉淀稀土后，与第二次收集的稀土浸出液混合，补加浸取剂，将混合液作为新鲜浸取剂返回稀土矿进行浸取作业。该分步收液循环浸取新工艺可降低水冶作业负荷，减少沉淀剂的消耗，提高稀土回收率，缩短生产周期。.将0.6 wt% DMDACC与2 wt% (NH4)2SO4进行复配，组成新型复合浸取剂对风化壳淋积型稀土矿进行浸取，发现稀土和铝的浸出率分别可达95%和90%以上，且该复合浸取剂能效改善矿体渗透性、缩短开采周期、降低山体滑坡等地质灾害发生的可能性。