横向注液条件下离子吸附型稀土堆体渗透特性模型试验研究

Test Study on Permeability Characteristics Model of Ion-Adsorbed Rare Earth Piles under Lateral Liquid Injection Conditions

针对传统离子吸附型稀土堆浸工艺顶部注液延迟植被修复的难题,提出了一种横向注液、适应植被修复的新型堆浸结构,并采用室内模型试验研究了横向注液条件下离子吸附型稀土的颗粒运移规律及渗透特性,分析了堆置时不同粒径颗粒组合对堆体渗透特性的影响。结果表明,横向注液条件下,离子吸附型稀土矿细颗粒的迁移和渗出导致稀土堆体的渗透性呈现“两端大、中间小”的空间分布不均匀性;随着浸矿液注液压力逐渐增加,渗透系数呈现出稳定、逐渐增大、再稳定和再次增大的变化过程;不同粒径颗粒组合对横向注液条件下离子吸附型稀土堆体的渗透性具有显著的影响,粗-细颗粒组合情况下细颗粒易发生迁移且难以沉积,易形成优势渗流通道,不利于稀土离子浸取,反之,中-细颗粒组合对离子吸附型稀土堆体的浸取最为有利。

During the traditional heap leaching of ion-adsorbed rare earth minerals,the top of the rare earth pile is covered with leaching liquid.This delays the time of vegetation restoration on the top of the pile.In order to solve this problem,a novel heap leaching structure with lateral liquid injection that is suitable for vegetation restoration is proposed.Aiming at the novel heap leaching structure,the particle migration and permeability characteristics of ion-adsorbed rare earth minerals under lateral liquid injection conditions are studied by laboratory tests.The effect of rare earth particle combinations at different particle sizes on the permeability characteristics of the pile is investigated.The results show that under lateral liquid injection conditions,the migration and exudation of the fine rare earth particles result in uneven distribution of the permeability in the pile.Specifically,the permeability is higher at both ends and lower in the middle of the rare earth pile.As the injection pressure of leaching liquid increases,the permeability coefficient shows a varying process of stability,gradual increase,re-stability and reincrease.The particle combinations at different particle sizes have an important effect on the permeability of the rare earth pile under lateral injection conditions.The combination of coarse particles and fine particles facilitates migration of the fine particles,and furthermore,those migrated fine particles are difficult to deposit.In this case,preferential flow paths of leaching liquid are easy to form,which is detrimental to rare earth ion leaching.On the contrary,the combination of fine particles and medium particles is most advantageous.