Pengcong Du, Renyu Geng, Jinming Jiang* , Huiliang Zhang, Jianwei Sun,Bin Du, Yanbo Zhang, Ruiyan Yu, Xuguang Wang, Weijun Gao
Utilization of ultra-fine fraction of gold tailings in autoclaved aerated concrete: Effects of mix design on mechanical properties and microstructure
https://doi.org/10.1016/j.dibe.2026.100882
金尾矿超细组分因粒径细小、比表面积大且黏土含量高,难以实现资源化利用。本研究提出一种新型节能利用方法:直接将 300–12000 目的金尾矿超细组分(UGT)作为硅质原料,替代蒸压加气混凝土(AAC)中的石英砂,从而省去能耗较高的球磨工序。本研究系统探究了石灰水泥比、钙硅摩尔比、水固比、铝粉掺量等关键配合比参数对浆体流变性能、力学性能及微观结构的影响规律。在最优配合比条件下,所制备的金尾矿超细组分蒸压加气混凝土(UGT-AAC)抗压强度达 4.33 MPa,干密度为 587 kg/m³,满足 A3.5、B06 等级标准要求。微观结构分析表明,材料强度发展主要依赖于托贝莫来石与水化硅酸钙凝胶形成的致密孔壁骨架结构,这一结果证实了金尾矿超细组分高值化利用的可行性。
The ultra-fine fraction of gold tailings is difficult to utilize due to their tiny size, large surface area, and high clay content. This study proposes a novel and energy-efficient approach by directly utilizing the ultra-fine fraction of gold tailings (UGT, 300–12,000 mesh) as a siliceous raw material to replace quartz sand in autoclaved aerated concrete (AAC), thereby eliminating the energy-intensive ball milling process. The effects of key mix design parameters, including the lime-to-cement ratio, calcium-to-silicon molar ratio, water-to-solid ratio, and aluminum paste dosage, on slurry rheology, mechanical properties, and microstructure were systematically investigated. Under the optimal mix proportion, the prepared UGT-AAC achieved a compressive strength of 4.33 MPa and a dry density of 587 kg/m3, meeting the A3.5 and B06 requirements. Microstructural analyses indicate that strength development is governed by a dense pore-wall skeleton formed by tobermorite and calcium silicate hydrate gels, demonstrating the feasibility of high-value utilization of UGT.
Shize Cai, Jinming Jiang* , He Wang**, Shiteng Tan, Yanbo Zhang, Ruiyan Yu,Xiaodong Wang, Koji Takasu, Weijun Gao
Environmental and economic assessment of coal fly ash flotation for sustainable unburned carbon recovery
https://doi.org/10.1016/j.dibe.2026.100882
Incorporating coal fly ash (CFA), a byproduct of coal combustion, into cementitious materials is a promising strategy for reducing the consumption of natural resources and mitigating environmental burdens. Although flotation effectively lowers the unburned carbon content in CFA to enhance its recyclability, the associated carbon emissions and economic costs necessitate rigorous sustainability evaluations. This study evaluates the environmental-economic trade-offs of CFA flotation at a Technology Readiness Level (TRL) 6 (pilot scale), utilizing integrated life cycle assessment (LCA) and life cycle cost analysis (LCCA). Instead of static modeling, a Calorific-Based Economic Valuation (CBEV) framework is introduced to optimize process parameters by coupling market pricing mechanisms with flotation grade-recovery. The results revealed that kerosene and turpentine oil dosages critically influenced system performance: overuse caused economic losses, whereas optimal conditions (1 % kerosene + 0.1 % turpentine oil per ton of CFA) achieved a carbon benefit of 94.29 kg CO2-eq (247.70 % improvement) and a net benefit of 0.986 USD/t (4.69 % return). Sensitivity analysis reveals that the adoption of electric vehicles yields synergistic environmental and economic benefits. In contrast, a 50 % increase in transport distance reduces economic returns by 3.6 %, despite a marginal variation in carbon footprint (<5 %), highlighting the importance of logistics optimization. Based on industrial scale-up principles, these results represent a conservative baseline for informing future industrial applications. This study establishes a dual-perspective framework for assessing the feasibility of CFA flotation and provides quantitative insights to support sustainable process intensification.
Jinming Jiang* , Renyu Geng **, Pengcong Du , Huiliang Zhang,Ruiyan Yu, Weijun Gao, Xi Meng
Comparative analysis of phase change composites based on circulating fluidized bed boiler fly Ash and pulverized coal-fired boiler fly Ash: Microstructure and thermal properties
https://doi.org/10.1016/j.jobe.2025.114569
粉煤灰是煤炭燃烧产生的副产物,作为一种低成本、热稳定性良好的载体,用于制备定形复合相变材料(SSCPCM)已受到广泛关注。然而,不同类型粉煤灰对复合材料性能的影响尚未得到系统对比研究。本研究旨在对比循环流化床粉煤灰(CFBFA)与煤粉炉粉煤灰(PCFFA)对定形复合相变材料微观结构及热学性能的影响。本研究中,研究人员对循环流化床粉煤灰和煤粉炉粉煤灰分别进行浮选、氢氧化钠活化及盐酸处理,随后以其为载体负载月桂酸 – 硬脂酸(LA-SA)共晶相变材料。通过扫描电子显微镜(SEM)、比表面积(BET)分析、X 射线衍射(XRD)、差示扫描量热法(DSC)及热重(TG)分析,对复合材料的结构与热学行为进行表征。结果表明:经氢氧化钠活化的循环流化床粉煤灰,尤其是浮选活化粉煤灰(MCFBFA),具有介孔结构与高比表面积,可实现相变材料的高效封装,其潜热值超过 84 J/g,且相变温度区间狭窄;相比之下,以煤粉炉粉煤灰为基材的复合材料结构致密、孔隙连通性有限,潜热值显著偏低,均低于 65 J/g。所有定形复合相变材料均表现出良好的热稳定性,起始分解温度均高于 120 ℃。上述研究结果证实,以浮选活化循环流化床粉煤灰为基材的复合材料与有机相变材料的相容性更优,在高效建筑储能领域展现出强劲的应用潜力。
Fly ash (FA), a byproduct of coal combustion, has attracted attention as a low-cost and thermally stable support for shape-stabilized composite phase-change materials (SSCPCM). However, the influence of different FA types on composite performance has not been systematically compared. This study aims to compare the effects of Circulating Fluidized Bed Boiler Fly Ash (CFBFA) and Pulverized Coal-Fired Boiler Fly Ash (PCFFA) on the microstructure and thermal properties of SSCPCM. In this study, CFBFA and PCFFA underwent flotation, NaOH activation, and HCl treatment, and were then used to support a lauric acid-stearic acid (LA-SA) eutectic phase change material. The structural and thermal behaviors were characterized using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric (TG) analysis. The results show that NaOH activated CFBFA, particularly its floated form (MCFBFA), provides a mesoporous structure and high surface area that allows for efficient PCM encapsulation, achieving latent heat values exceeding 84 J/g and narrow phase-change temperature ranges. In contrast, the PCFFA-based composites exhibited dense structures, limited pore connectivity, and significantly lower latent heat values below 65 J/g. All SSCPCM exhibited thermal stability, with decomposition onset temperatures above 120℃.These findings demonstrate that MCFBFA-based composites offer.superior compatibility with organic PCM and strong potential for high-efficiency building energystorage applications.
Shiteng Tan , Jinming Jiang * , Yuang Guo * , Hao Tang, Yali Gao, Shize Cai, Pei Li,Chao Liu *
Gender differences in sleep quality under summer thermal conditions: a case Study in a Qingdao dormitory
https://doi.org/10.1016/j.dibe.2026.100882
Thermal environments significantly influence sleep quality, yet gender-related differences under real summer conditions in cold climate zones remain underexplored. The present study conducted a field experiment in university dormitories in Qingdao, China, involving 30 healthy adults (15 males, 15 females) during summer 2024 and 2025. Indoor air temperature(Ta), relative humidity(RH), and CO₂ levels were continuously monitored, while mean skin temperature (MST)and sleep quality indicators were recorded using iButton sensors and Fitbit wristbands. Subjective thermal sensation and preference were assessed before sleep and after awakening. Statistical analysis included t-tests and multiple regression with interaction terms. Results showed that females had higher MST (34.62 ◦C) than males (34.42 ◦C) throughout the night and required higher neutral temperatures in Experimental Periods I (ΔT ≈ +0.87 ◦C) and Experimental Periods III(ΔT≈+0.02 ◦C). An increase of 1 ◦C in indoor Ta reduced deep sleep duration by 9.23 min for males and 10.58 min for females. Higher RH was associated with increased wake after sleep onset in females (+1.14 min/%RH) and reduced rapid eye movement duration in males (–1.80 min/%RH). These findings highlight gender-specific thermal comfort differences during sleep under air-conditioned summer conditions, with practical implications for energy-efficient indoor climate control and the design of personalized sleeping environments.
2025年10月11-12日,由亚洲城市环境学会与西安交通大学联合主办,联合国教科文组织气候教育办公室、世界工程组织联合会(WFEO)、亚洲低碳设计学会国际建筑环境学会、陕西省环境科学学会、陕西省土木建筑学会、陕西省人居环境科学学会、陕西地建-西安交大土地工程与人居环境技术创新中心等单位共同协办的“第22届亚洲城市环境学会国际会议”在西安交通大学创新港校区召开。本次会议以“气候适性城市与建筑设计”为主题,汇聚了来自全球的专家学者,共同探讨如何构建更具韧性与可持续性的气候适应性城市。
研究室吴晓灵同志与刘岩同志分别在会议上发表论文演讲,其中吴晓灵同志获得最佳汇报奖,热烈祝贺!!!!!!!
Jinming Jiang, Yanbo Zhang, Deao Kong, Ruiyan Yu, Shize Cai, Weijun Gao
Road Performance and Economic Benefits of Flotation-Modified Fly Ash for Stabilizing Collapsible Loess
Cement and Concrete Composites. https://doi.org/10.1016/j.cemconcomp.2025.106159
粉煤灰(FA)可部分替代水泥改善湿陷性黄土,降低水泥用量并推动可持续建设。本研究对循环流化床粉煤灰(CFBFA)、煤粉炉粉煤灰(PCFFA)及其浮选改性品(MCFBFA、MPCFFA)进行对比,掺量为10%,20%,30%并配合5%水泥。结果表明,浮选改性显著提升力学与耐久性能,其中30% MCFBFA效果最佳:28天UCS达5.26 MPa,CBR达46.9%,冻融损失仅12.17%,在OMC+2%条件下UCS升至5.91 MPa。经济分析显示,该方案较15%水泥对照组更具成本优势,并具浮选回收价值。综上,浮选改性FA为黄土稳定化提供经济、低碳的解决方案。
Fly ash (FA) can partially replace cement to improve collapsible loess, reducing cement consumption and promoting sustainable construction. This study compared circulating fluidized bed FA (CFBFA), pulverized coal furnace FA (PCFFA), and their flotation-modified products (MCFBFA, MPCFFA), incorporated at 10%, 20%, and 30% with 5% cement. Results show that flotation modification significantly enhanced mechanical and durability performance, with 30% MCFBFA performing best: 28-day UCS reached 5.26 MPa, CBR reached 46.9%, UCS loss after eight freeze–thaw cycles was only 12.17%, and at OMC + 2% the 28-day UCS increased to 5.91 MPa. Economic analysis indicated that this scheme is more cost-effective than the 15% cement control and also provides flotation recovery benefits. In summary, flotation-modified FA offers an economical, low-carbon solution for stabilizing collapsible loess.
Jinming Jiang, Ruiyan Yu, Renyu Geng, Shaochun Li ,Weijun Gao
Rheological behavior and mechanical performance of cement paste incorporating mixed flotation-modified fly ash
Journal of Building Engineering .Rheological behavior and mechanical performance of cement paste incorporating mixed flotation-modified fly ash – ScienceDirect
循环流化床锅炉飞灰(CFBFA)与煤粉炉飞灰(PCFFA)是我国主要的两类飞灰(FA),二者在颗粒形态与反应活性方面存在差异。尽管单独使用时均存在局限性,但它们的互补特性使其具备协同应用潜力。为提升性能并去除未燃尽碳,本研究采用泡沫浮选法对CFBFA与PCFFA进行协同处理。 本研究对水泥替代率为30%–50%、CFBFA/PCFFA配比为5种(10:0至0:10)的水泥浆体进行了性能评估。结果表明:纯PCFFA浆体及CFBFA/PCFFA配比为3:7的浆体,其屈服应力均低于88 Pa,流动性能得到改善;而替代率为50%的浆体则表现出更高的阻力,屈服应力超过118 Pa。在混合飞灰替代率为30%时,浆体的抗压强度达到最高,且高于纯CFBFA浆体。配比为1:1的混合飞灰(S5-M5)表现出显著的火山灰活性,能有效消耗氢氧化钙(Ca(OH)₂)并促进致密微观结构的形成。 X射线衍射(XRD)、扫描电子显微镜(SEM)、热重分析(TG)及压汞法(MIP)测试结果,证实了混合飞灰体系的协同水化行为。本研究为经浮选改性的混合飞灰提出了合理利用策略,该策略既可提升性能,又能推动混合飞灰在低碳建筑领域的可持续利用。