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Durability and microstructure analysis of the road base material prepared from red mud and flue gas desulfurization fly ash

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International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 555-568页

作者： Emile Mukiza Ling-ling Zhang xiao-ming liu School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China

The present study aimed to investigate the durability and microstructure evolution of road base materials(RBM)prepared from red mud and flue gas desulfurization fly *** durability testing showed that the strength of RBM with the blast furnace slag addition of 1wt%,3wt%and 5wt%reached 3.81,4.87,and 5.84 MPa after 5 freezing–thawing(F–T)cycles and reached 5.21,5.75,and 6.98 MPa after 20 weting–drying(W–D)cycles,*** results also indicated that hydration products were continuously formed even during W–D and F–T exposures,resulting in an increase of the strength and durability of *** observed increase of macropores(>1μm)after F–T and W–D exposures suggested that the mechanism of RBM deterioration is pore enlargement due to cracks that develop inside their ***,the F–T exposure showed a greater negative effect on the durability of RBM compared to the W–D *** leaching tests showed that sodium and heavy metals were solidified below the minimum requirement,which indicates that these wastes are suitable for use as a natural material replacement in road base construction.

关键词： red mud road base material durability microstructure damage mechanism

Hydration kinetics of cementitious materials composed of red mud and coal gangue

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International Journal of Minerals,Metallurgy and Materials 2016年第10期23卷 1215-1224页

作者： Na Zhang Hong-xu Li xiao-ming liu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction University of Science and Technology Beijing

To elucidate the intrinsic reaction mechanism of cementitious materials composed of red mud and coal gangue（RGC）, the hydration kinetics of these cementitious materials at 20°C was investigated on the basis of the Krstulovi？-Dabi？ model. An isothermal calorimeter was used to characterize the hydration heat evolution. The results show that the hydration of RGC is controlled by the processes of nucleation and crystal growth（NG）, interaction at phase boundaries（I）, and diffusion（D） in order, and the pozzolanic reactions of slag and compound-activated red mud-coal gangue are mainly controlled by the I process. Slag accelerates the clinker hydration during NG process, whereas the compound-activated red mud-coal gangue retards the hydration of RGC and the time required for I process increases with increasing dosage of red mud-coal gangue in RGC.

关键词： red mud coal gangue cementitious materials hydration kinetics

Recovery of scandium from bauxite residue——red mud:a review

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Rare Metals 2016年第12期35卷 887-900页

作者： Na Zhang Hong-Xu Li xiao-ming liu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction University of Science and Technology Beijing

Red mud is a slimy caustic residue generated from alumina production. Taking into account the rela- tively considerable content and availability of scandium, red mud can be viewed as an important and promising scandium resource rather than a solid waste. This paper is primarily to review the investigations of scandium recov- ery from red mud based on the most widely used hydrometallurgical processes including acid leaching, sol- vent extraction and ion exchange adsorption. It is thought that recovery of scandium from red mud should be con- sidered as a direct objective rather than a by-product in the development of overall flowsheet. In order to achieve environmentally-friendly processes with high scandium recovery and low cost, more attention is required to be paid to optimizing the selective leaching of scandium to decrease mineral acid consumption and alleviate pollution, and developing new solvent extraction systems and novel ion exchange adsorption materials with high selectivity and recognition for scandium.

关键词： Red mud Scandium Acid leaching Solvent extraction Ion exchange Selectivity

Flow fields control for bubble refinement induced by electromagnetic fields

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Journal of Iron and Steel Research International 2022年第4期29卷 575-587页

作者： Lian-yu Wang Ze-yi liu ming He xiao-ming liu Masamichi Sano Li-jia Zhao Qiang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

Large bubbles seriously reduce the efficiencies of the interactions between the bubbles and the molten steel,such as energy transfer,momentum transfer,mass transfer and chemical *** reduce the size of the bubbles and increase the gas–liquid interface area,a novel non-intrusive method of bubble refinement was proposed,which only depends on the molten steel flow field controlled by the rotating electromagnetic *** flow fields of the molten steel for bubble refinement were analyzed,and the corresponding bubble refinement was *** was found that the molten steel formed obvious rotating turbulent flow for bubble refinement under the unidirectional rotating electromagnetic ***,the large vortex in the center of the molten pool caused by the rotating flow made the bubbles aggregate and coalesce again,resulting in formation of larger bubbles and gas *** suppress the central vortex formation and enhance the bubble refinement,the forward-reverse rotating electromagnetic field for bubble refinement was *** irregular and chaotic flow occurred repeatedly because of alternating forward and reverse rotating in a short period,so that the turbulent kinetic energy and turbulent dissipation of the flow field always remained at a high level which favors bubble *** a result,the bubble diameter can decrease by more than 50%compared to that without electromagnetic ***,it is important that this non-intrusive kind of bubble refinement method completely avoids the introduction of non-metallic inclusions caused by intrusive configuration.

关键词： Bubble refinement Electromagnetic field Flow field Forward-reverse rotating Bubble Sauter

Relationship between the microstructure and reaction performance of aluminosilicate

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 108-115页

作者： xiao-ming liu Heng-hu Sun Xiang-peng Feng Na Zhang School of Resource and Safety Engineering China University of Mining ＆ Technology Beijing 100083 China School of Engineering and Computer Science University of the Pacific Stockton CA 95211 USA Shougang Environmental Protection Industry Department Beijing 100041 China Department of Civil and Environmental Engineering University of Wisconsin Madison W153706 USA

A systematic study was conducted to comprehend the mechanism of thermal activation of silica-alumina materials by using ^29Si and ^27Al magnetic angle spinning nuclear magnetic resonance （MAS NMR） spectroscopy. The reaction performance of silica-alumina-based materials with different molar ratios of Si/Al, which were thermally activated, was also investigated. With the increase in calcining temperature, the coordination of Al in metakaolin becomes four, five, and six firstly, and then transforms completely to four and six. It is indicated by identical coupled plasma optical emission spectroscopy （ICP） and NMR that, the reaction performance of monomeric silicate anions is better than that of polymeric silicate anions which are primarily cross-linked in the alkali solution. Moreover, it also shows that the thermal activation temperature, cooling method, and the molar ratio of Na/Ca have remarkable effects on the reaction performance.

关键词： calcination aluminosilicate reaction performance microstructure, nuclear magnetic resonance

Electron probe microanalysis for revealing occurrence mode of scandium in Bayer red mud

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Rare Metals 2017年第4期36卷 295-303页

作者： Na Zhang Hong-Xu Li Hui-Jing Cheng xiao-ming liu School of Metallurgical and Ecological Engineering Universityof Science and Technology Beijing Beijing 100083 China Beijing Key Laboratory of Rare and Precious Metals GreenRecycling and Extraction University of Science and TechnologyBeijing Beijing 100083 China State Key Laboratory of Advanced Metallurgy University ofScience and Technology Beijing Beijing 100083 China

Red mud is a bauxite residue generated during the process of alumina production. In this research, the occur- rence mode of scandium in the Bayer red mud was investi- gated mainly by electron probe microanalysis （EPMA）. The Bayer red mud used in this work is composed of 21.47 wt% hematite, 12.13 wt% goethite, 8.86 wt% gibbsite, 5.02 wt% perovskite, 9.70 wt% quartz, 3.23 wt% anhydrite, 29.92 wt% Na_2Al_2Si_5O_14 and 9.67 wt% Al_3Fe_5O_12. Besides, the scandium content in the Bayer red mud is 84.32 × 10-6, indicating that this Bayer red mud is an important scandium resource deserving exploitation. The EPMA results show that the scandium within the Bayer red mud is mainly occurring in the iron minerals of hematite and goethite with the isomorphism form, but its distribution is not homogeneous in these iron minerals with the Sc_2O_3 content between 330 × 10-6 and 2040 × 10-6. This study provides a theoretical base for the further experimental work on the scandium extraction from this Bayer red mud.

关键词： Scandium Occurrence mode Bayer red mud Electron probe microanalysis

Automatic recognition and intelligent analysis of central shrinkage defects of continuous casting billets based on deep learning

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Journal of Iron and Steel Research International 2023年第5期30卷 937-948页

作者： Gong-hao Lian Qi-hao Sun xiao-ming liu Wei-miao Kong ming Lv Jian-jun Qi Yong liu Ben-ming Yuan Qiang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina Shandong Iron and Steel Group Co. Ltd.Jinan 271105ShandongChina HBIS Material Technology Research Institude Shijiazhuang 050023HebeiChina Special Steel Business Department of Shandong Steel Laiwu Branch Jinan 271105ShandongChina

The internal quality inspection of the continuous casting billets is very important,and mis-inspection will seriously affect the subsequent production *** UNet-VGG16 transfer learning model was used for semantic segmentation of the central shrinkage defects of the continuous casting *** automatic recognition accuracy of the central shrinkage defects of the continuous casting billets reaches more than *** use the minimum circumscribed rectangle to quantify the geometric dimensions such as length,width and area of the central shrinkage defects and use the threshold method to rate the central shrinkage defects of the continuous casting *** results show that all the testing images are rated correctly,and this method achieves the automatic recognition and intelligent analysis of the central shrinkage defects of the continuous casting billets.

关键词： Central shrinkage Deep learning Image segmentation Circumscribed rectangle Automatic recognition

Composition evolution and deformation of different non-metallic inclusions in a bearing steel during hot rolling

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Journal of Iron and Steel Research International 2022年第4期29卷 552-562页

作者： Nan liu Gong Cheng Li-feng Zhang Wen Yang Ying Ren Guo-cheng Wang xiao-ming liu School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Steelmaking Plant Baotou Steel Union Co.Ltd.Baotou 014010Inner MongoliaChina Engineering Technology Co. Ltd.WISDRI Engineering and Research Incorporation LimitedWuhan 430223HubeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

The composition evolution and deformation of different non-metallic inclusions in a bearing steel during hot rolling were investigated by the automatic detection and the improved non-aqueous electrolysis *** sulfide,MnS–TiN,and liquid CaO–Al_(2)O_(3) inclusions were elongated while TiN and MgO-Al_(2)O_(3) were fractured during hot *** CaS–MnS phase in the MgO–Al_(2)O_(3)–CaS–MnS inclusion was separated from the inclusion,leading to the formation of CaS–MnS type ***,the CaS and MnS contents in oxide-containing inclusions decreased while the MgO and Al_(2)O_(3) contents increased after hot *** deformability of different inclusions in the bearing steel was quantitatively compared and discussed.

关键词： Bearing steel Hot rolling Composition evolution Deformability Inclusion

Rare earth element geochemistry in soils along arid and semiarid grasslands in northern China

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Ecological Processes 2022年第1期11卷 386-399页

作者： Yi‑Wen Cao xiao‑ming liu Chao Wang Edith Bai Nanping Wu CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China Department of Earth Marine and Environmental SciencesUniversity of North Carolina‑Chapel HillChapel HillNC 27515USA Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains School of Geographical SciencesNortheast Normal UniversityChangchun 130024China Institute of Deep‑Sea Science and Engineering Chinese Academy of SciencesSanya 572000China

Background:Rare earth elements(REE)are a group of trace elements that behave geochemically *** fractionation patterns normalized to reference materials provide a powerful tool for documenting *** processes are particularly difficult to illustrate with respect to contemporary and past climate *** this study,we characterize the rare earth element(REE)contents in bulk soils and respective geochemical fractions(e.g.,exchangeable,carbonate‑bound,reducible,and oxidizable fractions)and to decipher the relationships between REE geochemistry components and climatic factors across a large‑scale northern China transect(NCT).Results:Across the NCT,bulk REE concentrations ranged from 55.2 to 241.1μg g^(−1)with a main portion in the residual fraction(49–79%),followed by oxidizable fraction(2–40%),reducible fraction(3–22%),carbonate‑bound fraction(0.1–16%),and negligible exchangeable *** REE contents of geochemical components(carbonate‑bound,reducible,and oxidizable)in topsoils correlated to climate factors(mean annual precipitation,mean annual temperature,potential evaporation,and aridity index(AI)).The normalized abundances to the upper continental crust(UCC)composition show that the middle REE was generally enriched than the light REE and heavy REE in topsoils along the *** overall UCC‑normalized bulk REE patterns in topsoils and subsoils were similar,characterized by weak negative Ce anomalies and positive Eu ***:Our data in topsoils and depth profiles collectively suggest that cycling of REE was primarily regulated by abiotic processes in area with AI*** similar UCC normalized patterns in topsoils suggest that the REE was originated from a common source with limited influences from other sources(e.g.,atmospheric dusts and anthropogenic contribu‑tions).Our results to some extent provide evidence for

关键词： Rare earth elements Soil Grassland Northern China Aridity index