(1. 北京科技大学 金属矿山高效开采与安全教育部重点实验室，北京 100083;
2. 北京科技大学 土木与资源工程学院，北京 100083；
3. 江西离子型稀土工程技术研究有限公司，赣州 341000；
4. 国家离子型稀土资源高效开发利用工程技术研究中心，赣州 341000)
摘 要: 为揭示风化壳淋积型稀土矿浸出前后孔隙演化规律，对重配比矿样开展室内柱浸实验，分析柱浸过程溶浸液的渗出速率。基于CT无损探测技术及图像分析软件，研究在4%(质量分数)(NH4)2SO4的条件下风化壳淋积型稀土矿颗粒浸出前后孔隙结构微细观特征及其演化规律，得到浸出前后稀土矿体孔隙率在纵截面各分段的变化关系。结果表明：浸出液渗流速率与累计浸出时间呈负指数函数关系，渗流速率降幅在累积时间12 h前最为明显，之后其幅度减缓，累计时间24 h后其值趋于稳定，稳定速率为7.193×10-4 cm/s。浸出后反应器内的矿体高度减小0.866 cm，矿体发生了沉降，且矿物颗粒尺寸有所减小，孔隙不均匀分布程度提高，局部出现“泥化”现象，矿体浸出后孔隙率减小16.35 %。机制分析认为，矿物颗粒迁移和溶液化学作用是影响风化壳淋积型稀土浸矿孔隙结构演化的2个主要因素。
关键字: 风化壳淋积型稀土矿；柱浸；孔隙结构；CT 扫描；图像处理
（1. Key Laboratory of Ministry of Education for High-Efficient Mining and Safety of Metal, University of Science and Technology Beijing, Beijing 100083, China;
2. School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, China;
3. Jiangxi Ionic Rare Earth Engineering Research Co., Ltd., Ganzhou 341000, China;
4. National Engineering Research Center for Ionic Rare Earth, Ganzhou 341000, China）
Abstract:In order to reveal the regularity of pore evolution before and after leaching of weathered crust elution- deposited rare earth ore, laboratory column leaching experiment of reallocated ore sample was carried out, and the infiltration rate of the solution was analyzed. Based on non-destructive detection of CT and image analysis software, the micro-mesoscopic characteristics and evolution of pore structure before and after leaching in the presence of 4% (mass fraction) (NH4)2SO4 were disclosed. The relation of rare earth orebody’s porosity was also obtained in different longitudinal sections. The results show that the infiltration rate of the leaching solution is negatively exponentially related to the cumulative leaching time, and the rate decreases with time. The decrease of the infiltration rate is the most obvious in accumulated time of 12 h, and then the amplitude is slowed down. The seepage rate tends to a stable value after cumulative time of 24 h, and the rate is 7.193×10-4 cm/s. After leaching, the height of the ore body in the reactor reduces by 0.866 cm, the subsidence also occurs in the orebody, the particle size of the minerals is reduced, the uneven distribution of pores increases significantly, and some areas occur “muddy” phenomenon. The porosity decreases by 16.35% after the leaching of ore sample. The mechanism analysis shows that the migration of mineral particles and the chemistry of solution are two main factors influencing the evolution of leaching structure of weathered crust elution-deposited rare earth.
Key words: weathered crust elution-deposited rare earth ore; column leaching; pore structure; CT scanning; image processing
