风化壳淋积型稀土矿中阳离子与黏土矿物的交互作用机制

The weathered crust elution-deposited rare earth ore, as the main resources of middle and heavy rare earths in the world, has important industrial value. The rare earths existed as ions are absorbed by clay minerals and present as the ion-exchangeable phase, which can be chemical leached by electrolytes through ion exchange reaction. This essential characteristic is abstracted to the interaction mechanism of clay minerals and rare earths ions, impurity metal ions and leaching agent cations in this project. The Langmuir adsorption theory and the advanced molecular simulation software are applied to analyze the mechanism of clay minerals adsorbing cations to build the adsorption model. The leaching synergies of rare earths ions and impurity cations are illustrated by the Darcy law, so as to discuss the cation penetration law in the clay minerals, and propose a fast leaching technology for weathered crust elution-deposited rare earth ore. A novel leaching experimental scheme will be designed for the content determination of rare earths ions, impurity cations and leaching agent cations in the different layers of clay minerals at different leaching times to reveal the exchange mechanism of the three cations in clay minerals. All the above researches with important theoretical and industrial significances will provide larger amounts of basic theoretical data on the adsorption and leaching of weathered crust elution-deposited rare earth ore, thereby revealing its leaching nature, enriching the metallogeny and mining theories, and guiding the efficient leaching of rare earths.

风化壳淋积型稀土矿是世界中重稀土的主要来源，具有重要的工业应用价值。其特点是稀土以离子吸附于黏土矿物上，通过电解质溶液与稀土离子发生离子交换反应，实现化学浸取采选。本项目将这一本质特点凝练为稀土离子、杂质阳离子和浸取剂离子与黏土矿物的交互作用。通过Langmuir吸附理论和分子模拟软件分析黏土矿物吸附阳离子的作用机制，构建黏土矿物吸附三类阳离子的吸附模型。通过达西定律，阐述杂质阳离子与稀土离子的浸出协同效应，探讨黏土矿物中阳离子渗透规律，提出风化壳淋积型稀土矿快速浸矿工艺。设计新型浸矿试验方案，分析浸矿不同阶段和矿层中稀土离子、浸取剂离子和杂质阳离子的分布变化，揭示阳离子在黏土矿物上的交换作用机制。上述问题的研究和解决提供了风化壳淋积型稀土矿吸附、浸取基础理论数据，从而揭示风化壳淋积型稀土矿浸矿本质，丰富稀土成矿和采选化学理论，指导风化壳淋积型稀土矿的高效浸取，具有重要的理论和和工业意义。

风化壳淋积型稀土矿是世界中重稀土的主要来源，具有重要的工业应用价值。其特点是稀土以离子吸附于黏土矿物上，通过电解质溶液与稀土离子发生离子交换反应，实现化学浸取采选。本项目将这一本质特点凝练为稀土离子、杂质阳离子和浸取剂离子与黏土矿物的交互作用，开展了以下几个方面的研究：（1）探讨了风化壳淋积型稀土矿中典型黏土矿物高岭土、蒙脱土对稀土离子Y3+和La3+的吸附行为及吸附动力学，考察了高岭土、蒙脱土在稀土-铝二元体系中的吸附特性，从而揭示稀土离子与黏土矿物的吸附作用机制，获得杂质铝离子对黏土矿物吸附稀土离子的影响特性。（2）通过达西渗流定律研究浸取剂溶液在高岭土、蒙脱土、伊利石、风化壳淋积型稀土矿上的渗透规律，表征浸取剂溶液界面性质计算浸取剂溶液与矿物表面的黏附功，从而揭示浸取剂溶液浸取渗透机理。（3）设计新型浸矿实验方案，测定并计算浸矿不同浸取阶段和不同矿层中各种状态下的稀土阳离子和杂质铝离子含量变化，从而揭示风化壳淋积型稀土矿浸矿过程中稀土阳离子和杂质铝离子的迁移分布规律。（4）在风化壳淋积型稀土矿渗透性研究中发现，初始含水率可有效提高浸取剂溶液在矿体的渗透速率，从而进一步探讨了初始含水率对浸取过程的影响，提出了一种基于初始含水率的风化壳淋积型稀土矿快速浸矿工艺。（5）对比了甲酸铵、羟丙基甲基纤维素和田菁胶的助浸效果，结果表明甲酸铵的助浸效果较好，不仅可强化稀土浸出，还可降低浸出液中杂质铝离子含量，从而开发了风化壳淋积型稀土矿甲酸铵助浸优化工艺，并从渗透性、浸取动力学、浸取传质过程等方面探究了甲酸铵在风化壳淋积型稀土矿铵盐浸矿中的增效机制。上述研究为风化壳淋积型稀土矿浸取提供了基础理论数据，丰富了稀土成矿和采选化学理论，指导风化壳淋积型稀土矿的高效浸取，具有重要的理论和和工业意义。