Negative pressure liquid recovery technology has long been employed in the in-situ leaching of ionic rare earth (IRE) deposits. However, traditional systems face persistent challenges such as unstable vacuum maintenance and excessive energy consumption. While siphon-assisted vacuum drainage technology offers a promising solution to these limitations, the leaching characteristics of IRE under ponded infiltration with sustained negative pressure remain poorly understood. To address this knowledge gap, column reactor systems simulating in-situ leaching conditions were utilized to conduct comparative leaching experiments under atmospheric (0 kPa) and negative pressure (−60 kPa) conditions. Comprehensive analyses of solution ion migration, rare earth leaching dynamics, and leaching agent retention yielded the following conclusions: (1) Negative pressure significantly enhanced hydraulic efficiency, achieving 5.7-fold and 6.8-fold increases in infiltration and effluent discharge rates, respectively, while reducing the leaching cycle to 26 % of the atmospheric baseline. (2) Accelerated solute transport under negative pressure resulted in earlier RE3+ breakthrough, with concentration peaks occurring prematurely compared to atmospheric operations. (3) Reduced leaching agent retention was observed under negative pressure, with residual readily desorbable Mg2+ content decreasing by 15.9 % relative to atmospheric conditions. (4) IRE recovery exhibited a parabolic dependence on absolute negative pressure magnitude, peaking at an optimal threshold before declining due to preferential flow development. These findings establish negative pressure as an enhancement strategy for IRE extraction.

中文翻译：

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负压渗透条件下离子稀土浸出和浸出剂滞留行为

负压液体回收技术长期以来一直用于离子稀土 （IRE） 矿床的原位浸出。然而，传统系统面临着持续的挑战，例如真空维护不稳定和能耗过高。虽然虹吸辅助真空排水技术为这些限制提供了一种有前途的解决方案，但 IRE 在持续负压下的积塘渗透下的浸出特性仍然知之甚少。为了解决这一知识差距，利用模拟原位浸出条件的塔式反应器系统在大气压 （0 kPa） 和负压 （-60 kPa） 条件下进行比较浸出实验。对溶液离子迁移、稀土浸出动力学和浸出剂保留的综合分析得出以下结论：（1） 负压显著提高了水力效率，渗透和污水排放速率分别增加了 5.7 倍和 6.8 倍，同时将浸出周期降低到大气基线的 26%。（2） 负压下加速的溶质运输导致 RE3+ 的早期突破，与大气作相比，浓度峰值过早出现。（3） 在负压下观察到浸出剂保留率降低，残留的易解吸 Mg2+ 含量相对于大气条件下降了 15.9%。（4） IRE 恢复表现出对绝对负压幅度的抛物线依赖性，在最佳阈值处达到峰值，然后由于优先流动发展而下降。这些发现将负压确立为 IRE 提取的增强策略。