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Exfoliation of poly(ethylene glycol)-intercalated graphite oxide composite in water without sonication

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International Journal of Minerals,Metallurgy and Materials 2020年第6期27卷 840-845页

作者： Yang Hu Chun-bao Sun Jue Kou school of Civil and resource engineering University of Science and Technology BeijingBeijing 100083China

A novel method for exfoliating graphite oxide(GrO)was implemented through the mass water absorption of a GrO–poly(ethylene glycol)(GrO–PEG)*** GrO–PEG composite was prepared by intercalating PEG into the lamellae of GrO,and the variation of the basal spacing was measured by X-ray diffraction *** yield of graphene was measured with an ultraviolet–visible spectrophotometer,and the properties of graphene oxide(GO)were characterized by atomic force microscopy,transmission electron microscopy(TEM),Raman spectrometry,and Fourier transform infrared *** intercalation time was found to improve the yield of GO,whereas increasing the PEG molecular weight had the opposite *** GO sheets produced from the intercalation–absorption–exfoliation process were found to be a four-layer *** and Raman analyses indicate that the graphitized structure and oxygen groups of GO were preserved during the exfoliation *** importantly,the results show that good-quality GO could be prepared via a mild method involving water absorption of a GrO–PEG composite.

关键词： graphene oxide poly(ethylene glycol) intercalation exfoliation

Surface for methane combustion:O(^3P)+CH4→OH+CH3

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Chinese Physics B 2020年第7期29卷 286-294页

作者： Ya Peng Zhong-An Jiang Ju-Shi Chen school of Civil and resource engineering University of Science and Technology BeijingBeijing 100083China

Kinetic investigations including quasi-classical trajectory and canonical unified statistical theory method calculations are carried out on a potential energy surface for the hydrogen-abstraction reaction from methane by atom O(^3P).The surface is constructed using a modified Shepard interpolation *** ab initio calculations are performed at the CCSD(T)*** account of the contribution of inner core electrons to electronic correlation interaction in ab initio electronic structure calculations,modified optimized aug-cc-pCVQZ basis sets are applied to the all-electrons *** this potential energy surface,the triplet oxygen atom attacks methane in a near-collinear H-CH3 direction to form a saddle point with barrier height of 13.55 kcal/mol,which plays a key role in the kinetics of the title *** the temperature range of 298-2500 K,our calculated thermal rate constants for the O(^3P)+CH4→OH+CH3 reaction show good agreement with relevant experimental *** work provides detailed mechanism of this gas-phase reaction and a theoretical guidance for methane combustion.

关键词： methane combustion potential energy surface transition state kinetic ab initio electronic structure calculation

High Purity Mullite-Corundum Thermal Insulating Firebricks

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International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 237-241页

作者： Wen Ni Fengmei Liu(resource engineering school, University’ of Sctence and Technology Beijing Beijing. 100083, China) resource engineering school University of Science and Technology Beijing Beijing 100083 China

Laboratory and industrial experiments were carried out to study the possibility of producing high purity purity mullite-corundumthermal insulating firebricks. The results show that by using industrial alumina. natuual powder power, coal gangues and a small amountof additives. high purity mullite-corundum thermal insulating firebrieks can be produced The service. temperature of these brick can beup to 1780 with low. thermal conductivity' and good thermal shock resistance

关键词： mullite corundum thermal insulating firebricks

Effect of additives on iron recovery and dephosphorization by reduction roasting-magnetic separation of refractory high-phosphorus iron ore

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International Journal of Minerals,Metallurgy and Materials 2021年第12期28卷 1908-1916页

作者： Shi-chao Wu Zheng-yao Li Ti-chang Sun Jue Kou Xiao-hui Li school of Civil and resource engineering University of Science and Technology BeijingBeijing 100083China

The effect of CaCO_(3),Na_(2)CO_(3),and CaF_(2) on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe_(3)PO_(7) and apatite was *** results revealed that Na_(2)CO_(3) had the most significant effect on iron recovery and dephosphorization,followed by CaCO_(3),the effect of CaF_(2) was *** mechanisms of CaCO_(3),Na_(2)CO_(3),and CaF_(2) were investigated using X-ray diffraction(XRD),scanning electron microscopy and energy dispersive spectrometry(SEM-EDS).Without additives,Fe_(3)PO_(7) was reduced to elemental phosphorus and formed an iron-phosphorus alloy with metallic *** addition of CaCO_(3) reacted with Fe_(3)PO_(7) to generate an enormous amount of Ca_(3)(PO_(4))_(2) and promoted the reduction of iron ***,the growth of iron particles was *** the addition of Na_(2)CO_(3),the phosphorus in Fe_(3)PO_(7) migrated to nepheline and Na_(2)CO_(3) improved the reduction of iron oxides and growth of iron ***,the recovery of iron and the separation of iron and phosphorus were the *** contrast,CaF_(2) reacted with Fe_(3)PO_(7) to form fine Ca_(3)(PO_(4))2 particles scattered around the iron particles,making the separation of iron and phosphorus difficult.

关键词： alloy phosphorus separation

Dynamics of the CH4+ O(~3 P) → CH_3(ν= 0) + OH(■= 0) reaction

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Chinese Physics B 2018年第6期27卷 262-267页

作者： Zhong-An Jiang Ya Peng Ju-Shi Chen Gui Lan Hao-Yu Lin school of Civil and resource engineering University of Science and Technology Beijing Beijing 100083 China

The dynamics of the ground-state reaction of CH4＋ O（~3P） → CH3（ν = 0）＋ OH（ ν= 0） have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensive quasi-classical trajectory calculations of the vibrational distributions on a unique full-dimensional ab initio potential energy surface for the title reaction, at the collision energy of relevance to previous crossed molecular beam experiments. The surface is constructed using the all electrons coupled-cluster singles and doubles approach plus quasi-perturbative triple excitations with optimized basis sets. A modified Shepard interpolation method is also employed for the construction. Good agreement between our calculations and the available experimental results has been achieved, opening the door for accurate dynamics on this surface.

关键词： quasi-classical trajectory calculation vibrational distribution product-scattering distribution combustion reaction

Anti-adsorption mechanism of ion-adsorption type rare earth tailings

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Rare Metals 2023年第4期42卷 1420-1426页

作者： Wan-Fu Huang Hao Wu Xin-Dong Li Jia-Cai Ou Xiao-Lin Huang school of resource and Environmental engineering Jiangxi University of Science and TechnologyGanzhou341000China

To investigate the process of RE^(3+)anti-adsorption on ion-adsorption type rare earth tailings,the thermodynamics,adsorption kinetics and infrared spectroscopy of these materials were *** results indicate that the initial reaction rate of anti-adsorption of rare earth tailings is fast,but it reaches a balance in 6 *** formula 1-2a/3-(1-a)2/3=k_2t(k represents rate constant of the reaction,a represents anti-adsorption rate of rare earth ore,t represents anti-adsorption time)of internal diffusion can be used to predict the kinetics of anti-adsorption in IATRE ***ΔH0(ΔH,ΔG,ΔS represent change of enthalpy,Gibbs free energy and entropy,respectively),the anti-adsorption of RE^(3+)on ion-adsorption type RE tailings is a spontaneous physical adsorption *** effects of ligand exchange and strong chemical bond are not found in this *** the anti-adsorption process is exothermic,heating will inhibit the reaction and decrease the anti-adsorption *** to the infrared spectrum analysis,there are no significant changes in the mineral surface after *** on these findings,the anti-adsorption of rare earth tailings is physical adsorption.

关键词： Ion-adsorption type rare earth tailings Anti-adsorption Adsorption thermodynamics Adsorption kinetics

HR-TEM and FIB-SEM characterization of formation of eutectic-like structure from amorphous GdAlO_3-Al_2O_3 system

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中国有色金属学会会刊：英文版 2012年第S3期22卷 579-584页

作者： Y.H.HAN Y.HARADA J.F.SHACKELFORD Jaehyung LEE K.KAKEGAWA school of Materials science and engineering Yeungnam University Department of Chemical engineering and Materials science University of California at Davis graduate school of engineering Chiba University

The crystallization process of the eutectic composition of GdAlO_3-Al_2O_3 from the amorphous phase prepared by rapid-quenching of melt that leads to the formation of a cantaloupe skin-like microstructure was investigated using focused ion-beam scanning electron microscopy (FIB-SEM) and high-resolution transmission electron microscopy (HR-TEM).The amorphous films were heat-treated at temperatures between 1000 °C and 1500 °C for up to 30min to form the eutectic phases of GdAlO_3 and Al_2O_*** GdAlO_3 and Al_2O_3 crystal phases that formed from the amorphous phase were identified by FIB-SEM and *** components began to crystallize and grow from the amorphous phase separately at different *** formation process of these crystal phases was different from that of the ordinary eutectic microstructure solidified from the GdAlO_3-Al_2O_3 ***,the observed structure is termed "eutectic-like" for *** microstructures formed from the amorphous phases at sufficiently high temperatures consisted of ultra-fine microstructures of individually crystallized components and were similar to ordinary eutectic *** heat-treating the amorphous films at 1500 °C for either 2 min,8min or 30min,the ultra-fine components of GdAlO_3 and Al_2O_3 were found to crystallize following a eutectic-like stage after 8min of heat treatment.

关键词： eutectic amorphous GdAlO3-Al2O3 eutectic-like HR-TEM FIB-SEM Crystallization

Formation of calcium titanate in the carbothermic reduction of vanadium titanomagnetite concentrate by adding CaCO3

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International Journal of Minerals,Metallurgy and Materials 2020年第6期27卷 745-753页

作者： Xiao-hui Li Jue Kou Ti-chang Sun Shi-chao Wu Yong-qiang Zhao school of Civil and resource engineering University of Science and Technology BeijingBeijing 100083China

The formation of calcium titanate in the carbothermic reduction of vanadium titanomagnetite concentrate(VTC)by adding CaCO3 was *** analysis was employed to show the feasibility of calcium titanate formation by the reaction of ilmenite and Ca CO3 in a reductive atmosphere,where ilmenite is more easily reduced by CO or carbon in the presence of *** effects of CaCO3 dosage and reduction temperature on the phase transformation and metallization degree were also investigated in an actual roasting *** increase of CaCO3 dosages and reduction temperatures were found to be conducive to the formation of calcium titanate,and the optimum conditions were a CaCO3 dosage of 18 wt%and a reduction temperature of 1400°***,scanning electron microscopy–energy dispersive spectrometry(SEM–EDS)analysis shows that calcium titanate produced via the carbothermic reduction of VTC by CaCO3 addition was of higher purity with particle size approximately 50μ***,the separation of calcium titanate and metallic iron will be the focus in the future study.

关键词： vanadium titanomagnetite concentrate calcium carbonate carbothermic reduction metallic iron calcium titanate

Vibration reduction technology and the mechanisms of surrounding rock damage from blasting in neighborhood tunnels with small clearance

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International Journal of Mining science and Technology 2023年第5期33卷 625-637页

作者： Xiaodong Wu Min Gong Haojun Wu Guangfeng Hu Sijie Wang school of Civil and resource engineering University of Science and Technology BeijingBeijing 100083China

Interlaid rock is an important component in the construction of neighborhood tunnels that supports and reinforces the area between two ***,the blasting load during excavation can sometimes damage the interlaid rock and threaten the stability of a tunnel’s *** paper presents a case study of the small clearance section of the Liantang highway tunnel project in Shenzhen,China,where the minimum distance between the two tunnels involved is only 0.5 *** reduce the damage to the interlaid rock caused by blasting loads,we proposed a four-part excavation method with a vibrationcushioning rock layer in the following tunnel of neighborhood *** simulation was used to model the damage prevention mechanism of the vibration-cushioning rock layer and to better understand the propagation of cracks in the interlaid ***,based on the simulation results,combined microseismic controlled-blasting technology was implemented,using innovative blasting patterns combined with different charge structures and blasting equipment designed according to the varying thickness of the interlaid ***,this implementation succeeded in protecting interlaid rock during blasting operations.

关键词： Neighborhood tunnels Interlaid rock Rock damage Blasting design Ground vibration