5) Beijing Research Institute of Chemical Engineering Metallurgy,Beijing,101149,China Corresponding author,E-mail:heavenlil@163.com ABSTRACT To deeply understand the capillary diffusion and seepage hysteresis behavior of the leaching solution in the unsaturated ore heaps,this paper builds a capillary seepage model suitable for the unsaturated ore heap,uses COMSOL Multiphysics finite element numerical platform to carry out the capillary seepage visual simulation study,and uses the Time Domain Reflector (TDR)to in-situ, real-time detect the liquid holdup changes of unsaturated heap,explores the multi-factor response regulations of capillary seepage process based on Design Expert,and discusses the potential connection mechanism among the liquid holdup,capillary suction, porosity and irrigation rate of unsaturated ore heaps.The research results show that the heap porosity has an obvious impact on the heap liquid holdup than the irrigation intensity,and the increases convergence of liquid holdup improve with the spraying time,and ore heap with a small porosity takes longer time to reach steady status of liquid holdup.When the effect of liquid irrigation is not considered,the heap iquid holdup is positively correlated with the porosity ratio and hydraulic coduEspecially in the initial stage of irrigation period(0~20 s),the effects of irrigation rate,hydraulic conductivity and porosity ratio onore heap liquid holdup is more significant,an unsaturated ore pile solution capillary seepage model considering gas-liquid two-phase migration is preliminarily constructed;The capillary suction is more sensitive in the ore heap with a smaller porosity;The larger the irrigation rate and the smaller the porosity,the greater the capillary suction at the bottom of the ore heap,and it is easie ore heap to reach a steady-state of liquid holdup. KEY WORDS unsaturated ore heap:fluid flow behavior,seepage hysteresis apillary suction;liquid holdup;COMSOL multiphysics 堆浸技术凭借其基建周期短、投入成本低、作业安全性高等优势，被广泛应用于低品位硫化铜矿、砂 岩型金矿等战略矿产资源回采作业，。其中，堆浸是子种汽、固、液多相介质并存、渗流场、温度场、化 学场等多场耦合的复杂反应体系)；该体系中，溶液是溶准氧、Cu/Cu、Fe+Fe3#等有价金属离子等溶 质赋存的重要媒介，直接影响着反应传质过程与浸矿效率。因此，能否有效表征堆内溶液毛细扩散、流 动与分布规律是制约矿物浸出效率的重要因素。作为之种非饱和多孔介质中多相流，溶浸液的滞后现象是 普遍存在且十分复杂的阿。己有研究发现堆内溶液流动主要有两种形式6，刀：重力驱动的优势流和微观力驱 动的毛细扩散流。其中，由毛细管力驱动的毛细扩散过程，对溶液渗流迟滞行为的影响是十分显著的网。 毛细扩散过程不仅是影响矿堆渗流迟滞行为，更重要的会影响传质过程与浸矿效率，需要进一步深刻理解 和认识。 目前，针对非饱和堆内溶液渗流迟滞行为规律，特别是毛细扩散过程，国内外专家学者主要从物理实 验、 无损探测与数值模拟三介层面展开。其中，英国帝国理工大学Ilankoon等9，o开展矿堆溶液渗流迟滞 实验，利用持液率、残余稳念特液率对非饱和矿石颗粒堆的持液行为进行了研究：王雷鸣等立足于制粒 矿堆，基于自主研发的待液猴为原位监测系统实现了对不可动液、可动液的量化表征：毛细扩散过程对非 饱和堆（如破碎矿堆、制粒矿堆等）持液行为的影响不可忽略，毛细入渗率与毛细速率、含水率呈正相 关3，：随着多种无扰动探测设备技术的进步与引入，对溶液渗流的研究逐渐步入了微细观层面(，英 国剑桥大学Faga等利用核磁共振技术(Magnetic Resonance Imaging,.MRI)对堆内溶液扩散和溶液优势 流形成过程进行了研究，薛振林等s利用粒子图像测速技术(Particle Image Velocity,.PIV)对矿堆结构内溶 液渗流场进行了无损探测，有效实现了饱和溶液渗流场的可视化等。然而，单纯的实验研究与无扰动探测 存在实验误差大、瞬态短时、随机性强等劣势，难以实现对溶液渗流过程进行有效的预测。对此，多类数 学表征模型与渗流模拟软件逐渐被提出应用：国外Dixon、Petersen和Bouffard等l920合作研发了堆浸模拟 程序HeapSIM,可以对工业堆浸喷淋、矿物浸出实现过程监测与结果预测：我国W等2，利用COMSOL Multiphysics数值模拟软件和计算机断层扫描技术(Computed Tomography,CT)构建非饱和矿堆网格模型 并对堆内溶液渗流过程模拟，证实了堆内优势流动区与溶液停滞区：此外，马丹等2训聚焦裂隙岩体渗流， 利用Fluent开展了数值模拟研究，实现了破裂砂岩内的溶液流动规律。 综合已有研究不难发现，以往研究通常利用短时、瞬态可视化表征手段、数值模拟软件与相似物理渗5) Beijing Research Institute of Chemical Engineering Metallurgy, Beijing, 101149, China  Corresponding author, E-mail: heavenli1@163.com ABSTRACT To deeply understand the capillary diffusion and seepage hysteresis behavior of the leaching solution in the unsaturated ore heaps, this paper builds a capillary seepage model suitable for the unsaturated ore heap, uses COMSOL Multiphysics finite element numerical platform to carry out the capillary seepage visual simulation study, and uses the Time Domain Reflector (TDR) to in-situ, real-time detect the liquid holdup changes of unsaturated heap, explores the multi-factor response regulations of capillary seepage process based on Design Expert, and discusses the potential connection mechanism among the liquid holdup, capillary suction, porosity and irrigation rate of unsaturated ore heaps. The research results show that the heap porosity has an obvious impact on the heap liquid holdup than the irrigation intensity, and the increases convergence of liquid holdup improve with the spraying time, and ore heap with a small porosity takes longer time to reach steady status of liquid holdup. When the effect of liquid irrigation is not considered, the heap liquid holdup is positively correlated with the porosity ratio and hydraulic conductivity. Especially in the initial stage of irrigation period (0~20 s), the effects of irrigation rate, hydraulic conductivity and porosity ratio on ore heap liquid holdup is more significant; an unsaturated ore pile solution capillary seepage model considering gas-liquid two-phase migration is preliminarily constructed; The capillary suction is more sensitive in the ore heap with a smaller porosity; The larger the irrigation rate and the smaller the porosity, the greater the capillary suction at the bottom of the ore heap, and it is easier for ore heap to reach a steady-state of liquid holdup. KEY WORDS unsaturated ore heap; fluid flow behavior; seepage hysteresis; capillary suction; liquid holdup; COMSOL multiphysics 堆浸技术凭借其基建周期短、投入成本低、作业安全性高等优势，被广泛应用于低品位硫化铜矿、砂 岩型金矿等战略矿产资源回采作业[1, 2]。其中，堆浸是一种气、固、液多相介质并存、渗流场、温度场、化 学场等多场耦合的复杂反应体系[3]；该体系中，溶液是可溶性氧、Cu2+/Cu+、Fe2+/Fe3+等有价金属离子等溶 质赋存的重要媒介，直接影响着反应传质过程与浸矿效率[4]。因此，能否有效表征堆内溶液毛细扩散、流 动与分布规律是制约矿物浸出效率的重要因素。作为一种非饱和多孔介质中多相流，溶浸液的滞后现象是 普遍存在且十分复杂的[5]。已有研究发现堆内溶液流动主要有两种形式[6, 7]：重力驱动的优势流和微观力驱 动的毛细扩散流。其中，由毛细管力驱动的毛细扩散过程，对溶液渗流迟滞行为的影响是十分显著的[8]。 毛细扩散过程不仅是影响矿堆渗流迟滞行为，更重要的会影响传质过程与浸矿效率，需要进一步深刻理解 和认识。 目前，针对非饱和堆内溶液渗流迟滞行为规律，特别是毛细扩散过程，国内外专家学者主要从物理实 验、无损探测与数值模拟三个层面展开。其中，英国帝国理工大学 Ilankoon 等[9, 10]开展矿堆溶液渗流迟滞 实验，利用持液率、残余稳态持液率对非饱和矿石颗粒堆的持液行为进行了研究；王雷鸣等[11]立足于制粒 矿堆，基于自主研发的持液行为原位监测系统实现了对不可动液、可动液的量化表征；毛细扩散过程对非 饱和堆（如破碎矿堆、制粒矿堆等）持液行为的影响不可忽略[12]，毛细入渗率与毛细速率、含水率呈正相 关[13, 14]；随着多种无扰动探测设备技术的进步与引入，对溶液渗流的研究逐渐步入了微细观层面[15, 16]，英 国剑桥大学 Fagan 等[17]利用核磁共振技术（Magnetic Resonance Imaging, MRI）对堆内溶液扩散和溶液优势 流形成过程进行了研究，薛振林等[18]利用粒子图像测速技术（Particle Image Velocity, PIV）对矿堆结构内溶 液渗流场进行了无损探测，有效实现了饱和溶液渗流场的可视化等。然而，单纯的实验研究与无扰动探测 存在实验误差大、瞬态短时、随机性强等劣势，难以实现对溶液渗流过程进行有效的预测。对此，多类数 学表征模型与渗流模拟软件逐渐被提出应用：国外 Dixon、Petersen 和 Bouffard 等[19, 20]合作研发了堆浸模拟 程序 HeapSIM，可以对工业堆浸喷淋、矿物浸出实现过程监测与结果预测；我国 Wu 等[21, 22]利用 COMSOL Multiphysics 数值模拟软件和计算机断层扫描技术（Computed Tomography, CT）构建非饱和矿堆网格模型 并对堆内溶液渗流过程模拟，证实了堆内优势流动区与溶液停滞区；此外，马丹等[23, 24]聚焦裂隙岩体渗流， 利用 Fluent 开展了数值模拟研究，实现了破裂砂岩内的溶液流动规律。 综合已有研究不难发现，以往研究通常利用短时、瞬态可视化表征手段、数值模拟软件与相似物理渗 录用稿件，非最终出版稿