Minerals Engineering最新文献_第6页

Enhancing multi-sphere clump informed by particles geometry via correcting dynamic properties and mechanical interactions in DEM 通过修正DEM中的动态特性和力学相互作用，增强粒子几何形状的多球团块

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-12 DOI: 10.1016/j.mineng.2024.109153

Xuanquan Chen , Shunchao Qi , Yuntao Wang , Yonghao Liu , Jiawen Zhou , Xingguo Yang

Multi-sphere clumps are favored to approximate irregular particles in discrete element model (DEM) due to algorithmic simplicity and efficiency, which, however, leads to approximation errors in dynamical properties and contact forces for motion integration. The latter becomes substantial when cost-effective DEMs are pursued with an acceptable minimum number of subspheres per clump (SPC). This study endeavors to eliminate these errors while maintaining DEM accuracy for low-SPC clumps. Investigations are conducted on a new database where diversely shaped particles are triangulated and stored with local geometries of each vertex. Surface error is defined to quantify the deviation between each boundary subsphere of clump and its surrounding mesh vertices. Errors in dynamic properties are eliminated by optimizing subsphere density distribution via an unconstrained linear system. Contact force errors are alleviated by correcting stiffness via an average curvature radius weighted by local characteristic areas of surrounding vertices, and by correcting penetration depth via a local shape-weighted surface error as an offset approximation. A vertex-subsphere information mapping is established for real-time corrections in DEM. Results show that the enhanced clumps significantly improve DEM accuracy at low SPC. Once SPC

\geq

100, the predicted compression-rebound responses during dynamic collisions and stress–strain-strength behaviors from triaxial tests closely match the converged predictions at SPC = 300. Detailed analysis reveals that the correction of dynamic properties, surpassing the common voxel-grid approximation, achieves machine precisions and is crucial for updating particles motion/orientation in collision dynamics, while the correction of contact forces is more critical for quasi-static simulation by predicting more realistic microscopic force chains. Our findings suggest that the enhanced clumps at SPC = 100 can yield sufficiently high-accurate and cost-effective DEM, being promising for modern large-scale computations.

在离散元模型（DEM）中，多球团块由于算法的简单和高效，有利于近似不规则粒子，但这导致运动积分的动力学性质和接触力的近似误差。当追求具有成本效益的dem并使每个团块（SPC）的子球数量达到可接受的最低数量时，后者就变得非常重要。本研究努力消除这些误差，同时保持低spc团块的DEM精度。研究在一个新的数据库中进行，其中不同形状的粒子被三角化并存储与每个顶点的局部几何形状。定义了表面误差，以量化团块的每个边界子球与其周围网格顶点之间的偏差。通过无约束线性系统优化子球密度分布，消除了动态特性误差。通过由周围顶点的局部特征区域加权的平均曲率半径校正刚度，以及通过作为偏移近似的局部形状加权表面误差校正穿透深度，可以减轻接触力误差。建立了顶点-子球信息映射，实现了DEM的实时校正。结果表明，增强的团块显著提高了低SPC下的DEM精度。当SPC≥100时，动态碰撞过程中预测的压缩回弹响应和三轴试验的应力-应变-强度行为与SPC = 300时的收敛预测非常吻合。详细分析表明，动态特性的修正超越了常见的体素-网格近似，达到了机器精度，对于更新碰撞动力学中的粒子运动/方向至关重要，而接触力的修正通过预测更真实的微观力链而对准静态模拟更为关键。我们的研究结果表明，SPC = 100时的增强团块可以产生足够高精度和具有成本效益的DEM，有望用于现代大规模计算。

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引用次数: 0

QSAR study on molecular design and flotation prediction of collectors for copper sulfide 硫化铜捕收剂分子设计和浮选预测的 QSAR 研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-12 DOI: 10.1016/j.mineng.2024.109152

Wei Xiong , Wenfei Wang , Hong Zhong, Xin Ma, Shuai Wang

The development of flotation collectors is usually time-consuming and costly. Quantitative structure–activity relationship (QSAR) is one of the most powerful methods for designing and modifying molecules. Introducing QSAR into the development of collectors can significantly compensate for the above shortcomings. The molecular structure, conceptual density functional theory (CDFT) and electrostatic potential (ESP) are chosen as descriptors of xanthate in this article. Pearson correlation coefficient is used to filter descriptors to prevent overfitting, and a QSAR model is established for xanthate. The results of the model show that for the common xanthates, hydrophobicity and dipole moment can describe the relationship between their structure and flotation performance (R² = 0.9647). For the amide xanthates, the hydrophobicity, dipole moment, and non-polar region surface area can describe the relationship between their structures and flotation performance (R² = 0.9478). The accuracy of the model was verified using the test set, and the predicted flotation index (FI) values of sodium isobutyl xanthate (SIBX), potassium O-(6-(hexylamino)-6-oxohexyl) xanthate (PHAHX), potassium O-(6-(butylamino)-6-oxohexyl) xanthate (PBAHX) and potassium O-(4-(butylamino)-4-oxobutyl) xanthate (PBABX) were 0.7099, 0.8614, 0.8061, and 0.7631, respectively. And the relative errors with the experimental values were only 7.89 %, 1.85 %, 4.00 %, and 2.57 %, respectively, demonstrating the reliability of the established model. The QSAR model provides a theoretical basis for the subsequent design of collectors with better flotation performance and predicts the collecting capacities of collectors for chalcopyrite and pyrite.

浮选捕收剂的开发通常既耗时又昂贵。定量构效关系（QSAR）是分子设计和修饰最有力的方法之一。将QSAR引入收集器的开发可以显著地弥补上述缺点。本文选择分子结构、密度泛函理论和静电势作为黄原药的描述符。利用Pearson相关系数对描述符进行过滤，防止过拟合，并建立了黄原药的QSAR模型。模型结果表明，对于普通黄原酸盐，疏水性和偶极矩可以描述其结构与浮选性能的关系（R2 = 0.9647）。对于酰胺类黄药，疏水性、偶极矩和非极性区表面积可以描述其结构与浮选性能之间的关系（R2 = 0.9478）。利用试验集验证了模型的准确性，预测异丁基黄药钠（SIBX）、O-（6-（己胺基）-6-氧己基）黄药钾（PHAHX）、O-（6-（丁胺基）-6-氧己基）黄药钾（pbax）和O-（4-（丁胺基）-4-氧己基）黄药钾（PBABX）的浮选指数（FI）分别为0.7099、0.8614、0.8061和0.7631。与实验值的相对误差分别为7.89%、1.85%、4.00%和2.57%，表明所建立模型的可靠性。QSAR模型为后续设计浮选性能较好的捕收剂提供了理论依据，并预测了捕收剂对黄铜矿和黄铁矿的捕收能力。

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引用次数: 0

Investigation into sliding behavior of bubbles on a hydrophilic surface containing discretely distributed hydrophobic patches 研究气泡在含有离散分布的疏水斑块的亲水表面上的滑动行为

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-09 DOI: 10.1016/j.mineng.2024.109149

Zhongren Wu , Ai Wang , Siyuan Yang , Yijun Cao , Chao Li

Flotation of coarse particles with poor mineral liberation, aiming at gangue rejection at early stage, has attracted great attentions. Bubble detaching probability ultimately determines the coarse particle separation efficiency. To date, the bubble detaching behavior from the surface of coarse particles with poor liberation remains unclear. In this study, three sizes of bubbles (650 μm, 900 μm and 1200 μm) were generated to comparatively study their sliding behavior on a hydrophilic quartz substrate containing discretely distributed hydrophobic dots with a diameter of 100 µm and an edge distance of 400 µm. It was found that bubbles experienced stretching phase and sliding phase during the process. The initial three-phase contact line before sliding increased over the bubble size, resulting in greater force required to initialize bubble sliding. During the sliding process, the three-phase contact line remained the same for the bubble of 650 μm, while it exhibited a stepwise increase for the bubbles of 900 μm and 1200 μm, indicating that the sliding could stabilize bubble attachment to some extent for larger bubbles by strengthen the adhering force. Further study showed that the enhanced bubble attaching stability was only valid with the Reynolds number below 6222. The finding indicates that bigger bubbles may be able to benefit coarse particle flotation in a tranquil flow by providing stronger lifting force for particle ascending. It is believed that the outcomes of this study could facilitate the optimization of coarse particle flotation.

矿物解离性差的粗粒浮选，以早期截留脉石为目标，已引起人们的广泛关注。气泡分离的概率最终决定了粗颗粒的分离效率。迄今为止，气泡从松散的粗颗粒表面分离的行为仍不清楚。在本研究中，制备了三种尺寸（650 μm、900 μm和1200 μm）的气泡，对比研究了它们在含有直径为100 μm、边缘距离为400 μm的离散分布疏水点的亲水石英衬底上的滑动行为。结果表明，气泡在此过程中经历了拉伸阶段和滑动阶段。滑动前的初始三相接触线大于气泡尺寸，导致初始气泡滑动所需的力更大。在滑动过程中，650 μm气泡的三相接触线基本不变，而900 μm和1200 μm气泡的三相接触线逐渐增大，说明对于较大的气泡，滑动可以通过增强黏附力在一定程度上稳定气泡的附着。进一步研究表明，仅在雷诺数低于6222时，气泡附着稳定性增强才有效。研究结果表明，较大的气泡可以为颗粒上升提供更强的升力，从而有利于粗颗粒在静流条件下的浮选。研究结果对粗颗粒浮选工艺的优化具有一定的指导意义。

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引用次数: 0

Direct flotation recovery of malachite using a novel N-substituted hydroxamic acid: Adsorption mechanism and DFT calculation 使用新型 N-取代羟肟酸直接浮选回收孔雀石：吸附机理和 DFT 计算

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-09 DOI: 10.1016/j.mineng.2024.109133

Kangjing Wu , Yuxi Lu , Shuai Wang , Xin Ma , Hong Zhong

The weak collection ability of conventional benzohydroxamic acid (BHA) impedes its widespread application in the direct flotation of copper oxide minerals. Conversely, octyl hydroxamic acid (OHA) with enhanced hydrophobicity demonstrated superior collecting ability while exhibiting weak selectivity in malachite flotation. In order to achieve a balance between collecting ability and selectivity, we synthesized a novel N-cyclohexyl-N-hydroxyacetamide collector (ECHA) that featured similar structure of hydroxamate compounds and improved selectivity for the direct flotation of malachite. The bench-scale flotation results demonstrated that ECHA exhibited stronger collecting ability and excellent selectivity, 14.66% and 15.17% of copper recoveries increased than sodium butyl xanthate (SBX) and BHA, respectively. Contact angle tests, Zeta potential tests and solution chemistry analysis revealed that the interaction intensity of ECHA with malachite was significantly stronger than that of calcite and quartz. FTIR and XPS analysis showed that the reaction sites of ECHA were primarily located on the [–N(OH)CO–] group, suggesting possible chemisorption on the malachite surface. Additionally, DFT calculations indicated that the ECHA anion could potentially form a five-membered structure chelate complex with a Cu atom on the malachite surface through its [–N(OH)CO–] functional group. ECHA proved to be promising as an attractive collector in the direct flotation of malachite.

常规苯甲羟肟酸（BHA）的捕收能力较弱，阻碍了其在氧化铜矿物直接浮选中的广泛应用。相反，疏水性增强的辛烷基羟肟酸（OHA）在孔雀石浮选中表现出较强的选择性，但具有较好的捕收能力。为了在收集能力和选择性之间取得平衡，我们合成了一种新型的n -环己基- n -羟基乙酰胺捕收剂（ECHA），该捕收剂具有与羟酸酯化合物相似的结构，并提高了孔雀石的直接浮选选择性。实验结果表明，ECHA具有较强的捕收能力和良好的选择性，铜的回收率比丁基黄药钠（SBX）和BHA分别提高14.66%和15.17%。接触角测试、Zeta电位测试和溶液化学分析表明，ECHA与孔雀石的相互作用强度显著强于方解石和石英。FTIR和XPS分析表明，ECHA的反应位点主要位于[- n (OH)CO -]基团上，可能在孔雀石表面发生了化学吸附。此外，DFT计算表明，ECHA阴离子可能通过其[- n (OH)CO -]官能团在孔雀石表面与Cu原子形成五元结构的螯合物。ECHA是一种很有前途的捕收剂，可用于孔雀石的直接浮选。

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引用次数: 0

A comprehensive multiscale review of shaft furnace and reformer in direct reduction of iron oxide 竖炉和转炉在氧化铁直接还原中的多尺度综合评述

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-07 DOI: 10.1016/j.mineng.2024.109123

Masih Hosseinzadeh , Norollah Kasiri , Mehran Rezaei

The direct reduction of iron (DRI) process plays a pivotal role in the ironmaking and steelmaking industry and has emerged as a promising solution for reducing CO₂ emissions. This intricate process spans metallurgy and chemical engineering, encompassing multiple scales (macroscale, mesoscale, microscale, nanoscale) and various reaction systems, including catalytic gas–solid (reformer) and non-catalytic gas–solid (shaft furnace) processes. The shaft furnace operated as a multiscale moving bed reactor including iron oxide pellets where a complex interplay of 17 non-catalytic gas–solid reactions and several gas reactions is observed. This review covers all relevant fields of gaseous-based DRI and introduces essential mathematical models for shaft furnaces and reformers. Key non-catalytic gas–solid and shaft furnace models developed over the last century are compared and analyzed. The effects of crucial parameters such as solid structure, gas phase conditions, clustering, carbon formation, and lattice defects are discussed. In addition, the reformer in the DRI unit functions as a bottom-fired furnace, comprising a combustion chamber and tubes that carry three types of heterogeneous catalysts, operating as a fixed bed reactor. Diverse radiative and kinetic models have been discussed to characterize the combustion chamber and reactions in detail. Finally, the review discusses potential artificial intelligence (AI) applications in this context and identifies research gaps for future investigations.

直接还原铁（DRI）工艺在炼铁和炼钢工业中起着关键作用，并已成为减少二氧化碳排放的有前途的解决方案。这个复杂的过程跨越冶金和化学工程，涵盖多个尺度（宏观、中尺度、微观、纳米尺度）和各种反应系统，包括催化气固（重整炉）和非催化气固（竖炉）过程。竖炉作为包括氧化铁球团在内的多尺度移动床反应器运行，其中观察到17种非催化气固反应和几种气体反应的复杂相互作用。本文综述了基于气体的DRI的所有相关领域，并介绍了竖井炉和转化炉的基本数学模型。对上个世纪发展起来的主要非催化气固炉和竖炉模型进行了比较和分析。讨论了固体结构、气相条件、聚类、碳形成和晶格缺陷等关键参数的影响。此外，DRI装置中的重整器作为底燃炉，包括燃烧室和携带三种多相催化剂的管道，作为固定床反应器运行。讨论了各种辐射和动力学模型，以详细描述燃烧室和反应。最后，本文讨论了人工智能（AI）在这方面的潜在应用，并确定了未来研究的研究空白。

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引用次数: 0

Ex-situ mineral carbonation process challenges and technology enablers: A review from Australia’s perspective 非原位矿物碳酸化过程的挑战和技术推动因素：从澳大利亚的角度回顾

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-06 DOI: 10.1016/j.mineng.2024.109124

Dia Milani , Robbie McDonald , Phillip Fawell , Haftom Weldekidan , Graeme Puxty , Paul Feron

While reacting CO₂ with sub-surface mafic/ultramafic phases potentially captures greenhouse gas emissions, low porosity and very slow kinetics makes this problematic. Mineral processing tailings and mining wastes offer distinct particles with exposed surfaces that enhance reactivity, and Australia’s mining sector has numerous prospective tailings streams. Passive carbonation of such tailings is known, although reactivity is still usually low. This review evaluates the potential of accelerated mineral carbonation (AMC), engineered routes to facilitate mafic/ultramafic tailings carbonation.

The state-of-the-art of AMC technologies are evaluated in terms of operational principles, advantages, process challenges and environmental impacts. After providing a snapshot of Australia’s current mining industry, the best carbonation routes/practices for favorable rock types (e.g. wollastonite, serpentinite, olivine) are reviewed, highlighting their key Australian deposits or operations. Major challenges facing technology scale-up (CO₂ source, particle size and associated environmental risks) are analyzed. Integrating AMC with direct air capture (DAC) provides an adjacent pure, pressurized CO₂ stream to raise the viability of both technologies, while breakthroughs in secondary metal recovery or marketing carbonated end-products can also bolster business models. However, in the absence of supporting regulatory frameworks, major companies have been reluctant to adopt early-stage research, design and development to elevate AMC technologies toward commercialization.

虽然CO2与地下基性/超基性相反应可能会捕获温室气体排放，但低孔隙率和非常缓慢的动力学使其成为问题。矿物加工尾矿和采矿废物提供独特的颗粒，其暴露的表面增强了反应性，澳大利亚的采矿部门有许多潜在的尾矿流。这种尾矿的被动碳酸化是已知的，尽管反应性通常仍然很低。本文综述了加速矿物碳酸化（AMC）的潜力，以及促进基性/超基性尾矿碳酸化的工程路线。

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引用次数: 0

The synthesis of a novel flotation collector for bastnaesite, 5,5′-methylenedisalicylic acid, based on salicylhydroxamic acid molecular structure 基于水杨基羟肟酸分子结构的新型氟碳铈矿浮选捕收剂5,5′-亚甲基二水杨酸的合成

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-06 DOI: 10.1016/j.mineng.2024.109147

Peng Liu, Jianhua Kang, Weidi Zhang, Wei Sun, Mengjie Tian

In oxide mineral flotation, salicylhydroxamic acid (SHA) is a frequently employed collector renowned for its commendable selectivity. Nevertheless, SHA manifests an insufficient collecting efficacy in bastnaesite flotation. In response, the paper synthesized a novel collector, 5,5′-methylenedisalicylic acid (MDSA), by tethering two SHA molecules with a methylene group. In the flotation separation of bastnaesite and fluorite, MDSA collector exhibits an excellent selectivity. The synergistic application of MDSA collector and sodium alginate (SA) inhibitor effectively accomplishes the flotation separation of these two minerals. Zeta potential experiments and X-ray photoelectron spectroscopic tests consistently reveal that, with same MDSA doses in bastnaesite and fluorite slurries, MDSA possess heightened adsorption capacities on bastnaesite surface in contrast to fluorite. Consequently, in flotation experiments, the use of MDSA collector yields superior recoveries of bastnaesite compared to fluorite. Furthermore, the prior attachment of SA to fluorite interferes with the subsequent MDSA adsorption, whereas the initial SA binding to bastnaesite surface exerts a diminished influence on the subsequent adsorption of MDSA. First-principles calculations elucidate that MDSA can engage with two neighboring surface Ce³⁺ ions of bastnaesite through its two N-hydroxy amide groups, creating two pentacoordinate chelate rings and facilitating its adsorption onto bastnaesite surface. Furthermore, MDSA demonstrates a diminished adsorption energy on bastnaesite in contrast to fluorite.

在氧化物矿物浮选中，水杨基羟肟酸（SHA）是一种常用的捕收剂，以其优良的选择性而闻名。但在氟碳铈矿浮选中，SHA的捕收效果并不理想。为此，本文用一个亚甲基拴住两个SHA分子，合成了一种新型捕收剂——5,5′-亚甲基二白杨酸（MDSA）。在氟碳石和萤石的浮选分离中，MDSA捕收剂表现出良好的选择性。MDSA捕收剂与海藻酸钠抑制剂的协同应用，有效地实现了这两种矿物的浮选分离。Zeta电位实验和x射线光电子能谱测试一致表明，MDSA在氟碳石和萤石浆料中剂量相同时，MDSA在氟碳石表面的吸附能力比萤石高。因此，在浮选实验中，与萤石相比，使用MDSA捕收剂可获得更高的氟碳石回收率。此外，SA先前附着在萤石上干扰了随后的MDSA吸附，而SA最初附着在氟碳纳米管表面对随后的MDSA吸附的影响减弱。第一性原理计算表明，MDSA可以通过其两个n -羟基酰胺基团与相邻的两个碳纳米管表面Ce3+离子结合，形成两个五配位螯合环，促进其在碳纳米管表面的吸附。此外，与萤石相比，MDSA在氟碳石上的吸附能降低。

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引用次数: 0

Mechanism of synergistic effect of aluminum ions and water glass on talc flotation depression 铝离子与水玻璃协同抑制滑石浮选的机理

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-05 DOI: 10.1016/j.mineng.2024.109127

Tao Long , Qubing Li , Wei Yang , Sha Deng , Xiangyu Peng , Jianping Jin

Talc, a prevalent gangue mineral in sulfide ores, poses a significant challenge in the flotation process due to its good floatability. The application of water glass as a standalone reagent has been found to be less effective in suppressing talc. In this study, we delve into the synergistic inhibitory mechanism of Al³⁺ in conjunction with water glass on talc through a series of micro-flotation tests, wettability tests, ICP-MS tests and FTIR spectroscopy tests. Our findings demonstrated that the presence of Al³⁺ significantly enhanced the adsorption capacity of water glass on talc surface. Talc recovery was 23.34 % with the addition of both inhibitors, which was lower than the recovery of 55.82 % with the addition of water glass only. DFT calculation revealed that the adsorption of H₄SiO₄ and [H₃SiO₄]⁻ on the talc surface is relatively weak, with adsorption energies of −7.71 kJ/mol and −23.15 kJ/mol. Following the adsorption of Al³⁺ onto the talc surface, the adsorption energies of H₄SiO₄ and [H₃SiO₄]⁻ were further decreased to −78.41 kJ/mol and −119.63 kJ/mol. The presence of Al³⁺ significantly enhanced the interaction between water glass and the talc surface. This enhancement was attributed to the formation of hydrogen bonds between water glass and the Al³⁺ water complex–Al(OH)₃·H₂O, which augmented the interaction with the talc surface.

滑石是硫化物矿石中常见的脉石矿物，由于其良好的可浮性，给浮选工艺带来了很大的挑战。用水玻璃作为单独的试剂抑制滑石的效果较差。本研究通过一系列的微浮选试验、润湿性试验、ICP-MS试验和FTIR光谱试验，探讨了Al3+与水玻璃对滑石的协同抑制机理。研究结果表明，Al3+的存在显著增强了水玻璃在滑石表面的吸附能力。添加两种抑制剂时，滑石回收率为23.34%，低于仅添加水玻璃时的55.82%。DFT计算表明，H4SiO4和[H3SiO4]−在滑石表面的吸附较弱，吸附能分别为−7.71 kJ/mol和−23.15 kJ/mol。Al3+在滑石表面吸附后，H4SiO4和[H3SiO4] -的吸附能进一步降低至- 78.41 kJ/mol和- 119.63 kJ/mol。Al3+的存在显著增强了水玻璃与滑石表面的相互作用。这种增强是由于水玻璃与Al3+水络合物- al (OH)3·H2O之间形成氢键，增强了与滑石表面的相互作用。

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引用次数: 0

Extraction of precious metals from waste printed circuit boards using alkaline ferricyanide solutions: An exploratory study 用碱性铁氰化溶液从废弃印刷电路板中提取贵金属：探索性研究

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-05 DOI: 10.1016/j.mineng.2024.109144

Huan Li , Elsayed Oraby , Jacques Eksteen , Wenhao Xie , Jing Gu , Haoran Yuan

Precious metals leaching using conventional processes presents challenges due to the use of toxic, expensive, and complex leaching systems, such as cyanidation, thio-systems, and halide systems comprising both lixiviant and oxidant. The present study employed a simple leaching system of alkaline ferricyanide solution with dual functions of leaching and oxidization, to extract precious metals from waste printed circuit boards (PCBs). The ferricyanide concentration, pH and temperature were found affecting Au extraction considerably. The selective extraction of Au, Ag and Pd over base metals reached 68.3, 93.0 and 74.0 % (10 g/L ferricyanide, pH 11 and 80℃), respectively. The recovery of precious metals from leachate using carbon adsorption and the regeneration of ferricyanide from barren solutions employing ferri/ferrocyanide redox cycle were shown feasible. Around 91.7 % ferricyanide could be regenerated by oxidising ferrocyanide using potassium permanganate. Finally, conceptual flowsheets were proposed to extract and recover precious metals and to regenerate and reuse the only reagent introduced ferricyanide. The study proved the feasibility of the simple leaching method, paving the way for future development of the new process.

由于使用有毒、昂贵和复杂的浸出系统，例如氰化、硫代系统和包含浸出剂和氧化剂的卤化物系统，使用传统工艺浸出贵金属带来了挑战。采用一种具有浸出和氧化双重功能的碱性铁氰化溶液的简单浸出系统，从废弃印刷电路板（pcb）中提取贵金属。铁氰化物浓度、pH和温度对金的提取有较大影响。在10 g/L铁氰化物、pH 11和80℃条件下，Au、Ag和Pd对贱金属的选择性萃取率分别达到68.3、93.0和74.0%。采用碳吸附法回收渗滤液中的贵金属，采用铁/亚铁氰化物氧化还原循环从贫液中再生铁氰化物。用高锰酸钾氧化亚铁氰化物可再生约91.7%的铁氰化物。最后，提出了贵金属的提取和回收以及铁氰化物的再生和再利用的概念流程。研究证明了简单浸出法的可行性，为今后新工艺的发展铺平了道路。

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引用次数: 0

Dynamics of gas dispersion in a rising bubble plume in presence of surfactant 表面活性剂作用下上升气泡羽流中气体分散动力学

IF 4.9 2区工程技术 Q1 ENGINEERING, CHEMICAL

Minerals Engineering

Pub Date : 2024-12-05 DOI: 10.1016/j.mineng.2024.109145

Abdullaziz Glabe Zakari, Mohammad Mainul Hoque, Peter Ireland, Geoffrey Evans, Subhasish Mitra

Understanding dispersion behaviour of bubbles emitting from a sparger is a critical element of mineral flotation process. This aspect was investigated in the present study involving a bubble plume in a semi-batch rectangular column in the presence of an anionic surfactant. First, high-speed imaging was used to visualise the bubble plume behaviour at different air flow rates (0.1 – 0.5 L/min). An image processing code was developed to determine the mean bubble diameter which indicated a decrease in the mean bubble diameter from ∼ 0.60 mm to 0.51 mm with increasing gas flow rates. A transient 3D Eulerian-Eulerian multiphase CFD model with a bubble population balance sub-model was also developed to quantify the gas holdup and turbulence energy dissipation rate distribution in this system utilising the experimentally measured mean bubble size. Experimentally, it was observed that symmetry of the bubble plume was disrupted at higher gas flow rates leading to larger dispersion of gas bubbles towards the top of the column. This observation was explained by the CFD model which predicted asymmetric transverse velocity profiles that increased in the axial direction. The model also predicted increasing gas holdup in the system (∼0.02 to 0.11) with increasing gas flow rates. The corresponding turbulence energy dissipation rate increased from ∼ 0.014 to 0.076 m²/s³ with maximum turbulent energy dissipation rate occurring near the gas distributor zone. Also, a transition from a bubbly to a distinct foam zone was noted at the free surface in the higher gas flow rate cases which was explained by the turbulence energy dissipation rate in the system.

了解喷淋机中气泡的分散行为是矿物浮选过程的关键因素。这方面的研究，在本研究涉及一个气泡柱在半批矩形柱在阴离子表面活性剂的存在。首先，使用高速成像来可视化不同空气流速（0.1 - 0.5 L/min）下的气泡羽流行为。开发了一个图像处理代码来确定平均气泡直径，该代码表明随着气体流速的增加，平均气泡直径从0.60 mm减少到0.51 mm。建立了含气泡种群平衡子模型的瞬态三维欧拉-欧拉多相CFD模型，利用实验测量的平均气泡尺寸量化系统中的气含率和湍流能量耗散率分布。实验结果表明，在较高的气体流速下，气泡羽流的对称性被破坏，气泡向塔顶弥散较大。这一现象可以用CFD模型来解释，该模型预测了不对称的横向速度分布在轴向增加。该模型还预测，随着气体流速的增加，系统中的气体含率也会增加（~ 0.02 ~ 0.11）。相应的湍流能量耗散率从~ 0.014增加到0.076 m2/s3，最大的湍流能量耗散率出现在气体分布区附近。此外，在高气体流量的情况下，自由表面由气泡区过渡到明显的泡沫区，这可以用系统中的湍流能量耗散率来解释。

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