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Rare Metals 2014年第6期33卷 754-760页

作者： wen-Cheng Gao Jian-kang wen Biao Wu He Shang National Engineering Laboratory of Biohydrometallurgy General Research Institute for Nonferrous Metals

A novel process of extracting niobium, yttrium,and cerium from a low-grade niobium-bearing ore by the roasting（NH4）2SO4-Na2SO4-H2SO4 system was experimentally studied. The influences of various factors,such as roasting temperature, roasting time, mass ratio of agents-to-ore and particle size fraction on the extraction of valuable metals were comprehensively investigated. It is found that the roasting Na2SO4-H2SO4 system is effective to extract the niobium, yttrium, and cerium. The obtained optimum conditions for the extraction of Nb, Y, and Ce are roasting temperature of 300 °C, roasting time of 3 h, mass ratio of Na2SO4：H2SO4：Ore of 0.5：1.0：1.0, and particle size fraction of-74 lm（~95 %）. Under the optimum condition, the maximum recovery of Nb, Y, and Ce can reach90.53 %, 92.15 %, and 98.04 %, respectively. All the results generated from this study will provide the fundamentals for Nb, Y, and Ce extraction from a niobiumbearing ore with low-grade.

关键词： Extraction Niobium Yttrium Cerium Lowgrade

A novel approach to extract Nb,Y and Ce from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4) system

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Rare Metals 2021年第7期40卷 1979-1986页

作者： wen-Cheng Gao Jian-kang wen Biao Wu He Shang Xue Liu National Engineering Laboratory of Biohydrometallurgy GRIMAT Engineering Institute Co.LtdBeijing 101407China GRINM Resources and Environment Tech.Co. LtdBeijing 101407China

In this work,a novel approach of leaching valuable metals,such as niobium,yttrium and cerium,from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4)system was experimentally *** the work,the effects of roasting temperature,roasting time,mass ratio of agents to ore and the types of leaching agents on the extraction of Nb,Y and Ce were investigated,and the roasting KHSO_(4)-H_(2)SO_(4)-ore system was thought as an effective method to extract these valuable *** was found that the recovery of Nb,Y and Ce can,respectively,reach 90.20%,97.22%and 98.41%in condition of roasting temperature of 300℃,roasting time of 2 h,mass ratio of KHSO_(4)-to-H_(2)SO_(4)to ore of 0.5:1:1,particle size of-74 lm(~95%),leaching solution of oxalic acid(30 g·L^(-1)),leaching temperature of 90℃and leaching liquid-to-solid ratio of 5:*** leaching kinetics of the calcined Nb-bearing ore in oxalic acid solution was successfully modeled by chemical reaction model,and the apparent activity energy was obtained to be14.16 kJ·mol^(-1).The results generated from this work will provide the fundamentals for extracting Nb,Y and Ce from a niobium-bearing ore of low grade and have potential applications value in future.

关键词： Roasting Extraction Niobium Yttrium Cerium Low grade

Sulfuric acid leaching of low-grade refractory tantalum–niobium and associated rare earths minerals in Panxi area of China

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Rare Metals 2015年第3期34卷 202-206页

作者： Biao Wu He Shang Jian-kang wen National Engineering Laboratory of Biohydrometallurgy General Research Institute for Nonferrous Metals

By mineral liberation analyzer （MLA） automated quantitative system, the niobium-tantalum ore in this study was classified as refractory mineral of low-grade which was mainly composed of fergusonite, polycrase, ilmenorutile, and bastnasite. Most of niobium and rare earth metals were dis- seminated in these minerals （particle sizes of 95 % rare earth elements 〈40 μm）, which cannot be concentrated through traditional floatation process and treated by the current hydrofluoric acid leaching in industry application. It is nec- essary to develop a new approach to recovery these valuable metals. In this study, an improved method is proposed to extract these metals, which includes acid roasting and sulfuric acid leaching. The influence of mineralogy, acid concentra- tion, leaching temperature, leaching time, and liquid to solid ratio was experimentally studied. It is observed that after the ground ore （-74 μm） was roasted at 350 ℃ for 2 h with sulfuric acid （18.4 mol.L- 1） in the ore to acid mass ratio of 1：1, and then the roasting residue reacted with 25 % sulfuric acid at 90 ℃ for 2 h, the recovery rate of rare earth elements reaches 〉90 %, and the leaching extent of niobium can reach 84 %.

关键词： Niobium-tantalum Rare earth Refractory Low-grade Roasting Sulfuric acid leaching

Predicting roof-surface wind pressure induced by conical vortex using a BP neural network combined with POD

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Building Simulation 2022年第8期15卷 1475-1490页

作者： Fubin Chen wen kang Zhenru Shu Qiusheng Li Yi Li YFrank Chen kang Zhou School of Civil Engineering Changsha University of Science and TechnologyChangsha410082China School of Civil Engineering Central South UniversityChangsha410083China Department of Architecture and Civil Engineering City University of Hong KongKowloonHong KongChina Hunan Provincial Key Laboratory of Structures for Wind Resistance and Vibration Control&School of Civil Engineering Hunan University of Science and TechnologyXiangtan411201China Department of Civil Engineering The Pennsylvania State UniversityMiddletownPA 17057USA

This study aims to examine the feasibility of predicting surface wind pressure induced by conical vortex using a backpropagation neural network(BPNN)combined with proper orthogonal decomposition(POD),in which a 1:150 scaled model with a large-span retractable roof was tested in wind tunnel under both laminar and turbulent flow *** distributions of mean and fluctuating wind pressure coefficients were first described,and the effects of inflow turbulence,wind direction,roof opening were examined *** the prediction of wind pressure,the POD-BPNN model was trained using measurement data from adjacent *** prediction results are overall *** root-mean-square-error(RMSE)between test and predicted data lies mostly within 10%.In particular,the prediction of mean wind pressure is found to be better than that of fluctuating wind *** outcomes in this study highlight that the proposed POD-BPNN model can be well used as a useful tool to predict surface wind pressure.

关键词： wind tunnel test-roof-surface wind pressure conical vortex proper orthogonal decomposition(POD) backpropagation neural network(BPNN)

Numerical simulation of gas-liquid two-phase flow impacting fixed structure by CLSVOF/IB method based on OpenFOAM

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Journal of Hydrodynamics 2021年第6期33卷 1176-1189页

作者： wen-kang Meng Ching-hao Yu Jia Li Rui-dong An State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China

In this paper,a coupled level set and volume of fluid,immersed boundary(CLSVOF/IB)method is proposed and implemented into the interFoam solver of the OpenFOAM to simulate the gas-liquid two-phase flows,involving the gas-liquid and fluid-structure *** the volume of fluid(VOF)method,the multidimensional universal limiter with explicit solution(MULES)approach is used to restrain the volume *** approach for calculating the grid characteristic size for the level set(LS)initial function and the re-initialization equation is proposed in order to make it more applicable to non-uniform grids in the finite volume *** the proposed CLSVOF method,the continuous LS function is used to calculate the gas-liquid interface curvature so that the surface tension term can be calculated *** the immersed boundary(IB)method proposed in this paper,a virtual forcing term is introduced in the momentum equation to deal with the fluid-structure interface by defining a solid volume fraction,which is convenient for the three-dimensional numerical *** the present flow field solver,an improved scheme of the velocity predictor loop of the PIMPLE framework is also *** benchmark cases:the Zalesak’s notched disk and a circular bubble at equilibrium,are simulated first to examine the accuracy of the present CLSVOF ***,the effects of several gas-liquid two-phase flows on different fixed structures are *** simulation results are in good agreement with the published numerical and experimental results.

关键词： Volume of fluid(VOF)method level set(LS)method immersed boundary method gas-liquid interface fluid-structure interface

Biological Cycles of Mineral Elements in a Young Mixed Stand in Abandoned Mining Soils

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Journal of Integrative Plant Biology 2007年第9期49卷 1284-1293页

作者： Da-Lun Tian wen-Hua Xiang wen-De Yan wen-Xing kang Xiang-wen Deng Zhu Fan Research Section of Ecology Central-South University of Forestry & Technology Changsha 410004 China

Phytoremediation as a sustainable and inexpensive technology based on the removal of pollutants from the environment by plants is becoming an increasingly important objective in plant research. In this study, biological cycles of five nutrient elements （N, P, K, Ca, and Mg） and eight heavy metal elements （Fe, Cu, Zn, Mn, Cd, Ni, Pb and Co） were examined in young paniculed goldraintree （Koelreuteria paniculata Laxm） and common elaeocarpus （Elaeocarpus decipens） mixed stands in an abandoned mining area. We found that after vegetation restoration in abandoned mining areas, the organic matter and concentrations of nutrient elements were significantly increased and the heavy metal elements were significantly decreased, the annual retention, uptake and return were 75.0, 115.4, and 40.3 kg/hm^2 for nutrient elements, and 1 878.0, 3 231.0 and 1 353.0 g/hm^2 for heavy metal elements, respectively, with the utilization coefficient, cycling coefficient and turnover rate of 0.92, 0.35 and 0.32 for nutrient elements, and 1.24, 0.42 and 1.92 for heavy metal elements, respectively. Our results suggested that the vegetation restoration in abandoned mining areas had significant effects in improving environmental conditions, enhancing soil available nutrients, and ensuring human health.

关键词： abandoned mining areas biological cycle common elaeocarpus (Elaeocarpus decipens) heavy metal elements mixed stand paniculed goldraintree (Koelreuteria paniculata).

Effect of adding Lactobacillus plantarum and soluble carbohydrates to swine manure on odorous compounds, chemical composition and indigenous flora

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Journal of Environmental Sciences 2006年第1期18卷 201-206页

作者： HUANG Can LI Ji kang wen-li TANG Xin-yan College of Resources and Environment Sciences China Agriculture University Beijing 100094 China College of Animal Sciences Zhejiang University Hangzhou 310029 China

Manure odor, which results in the increasing complaints and lawsuits, has increased the tension among swine producers and surrounding residents. The effects of Lactobacillus plantarum and different rates of soluble carbohydrates additions to swine manure on odorous compounds, chemical compounds and indigenous flora were evaluated. Additions were calculated on dried manure weight basis. Variables monitored included ammonia （NH3）, hydrogen sulfide （H2S）, odor offensiveness, pH, ammonium nitrogen（NH4^＋-N）, volatile fatty acids （VFAs）, urease and indigenous flora. The results indicated that the combination of L. plantarum and soluble carbohydrates dramatically reduced manure pH. Lower pH resulted in the reduction of NH3 volatilization （34.6%-92.4%, P〈0.01）, the increases of H2S （P〈 0.05） and NH4^＋-N （5.3%-17.5%, P〈0.05）. In addition, L. plantarum and soluble carbohydrates additions significantly reduced odor offensiveness, those VFAs related to malodor indicators（valeric acids, 12.3%-47.7%, P〈 0.05; iso-valeric, 3.5%-23.8%） and the main microorganisms responsible for odor production, with the number of Eubacteria in swine manure reducing by 4.9%, 11.6%, 17.4%, 34.1% and 32.2% respectively.

关键词： Laetobaeillus plontarum soluble carbohydrates swine manure odorous compounds indigenous flora

Magnesium-rich gangue dissolution in column bioleaching of chalcopyrite

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Rare Metals 2015年第5期34卷 366-370页

作者： Xue Liu Jian-kang wen Biao Wu Shuang Liu National Engineering Labortory of Biohydrometallurgy General Research Institute for Nonferrous Metals

This study is to assess the effect of magnesiumrich gangue dissolution on the ore containing chalcopyrite and carrollite from Democratic Republic of the Congo （DRC）. The ore contains 11.0 wt% magnesium and 2.4 wt% copper. When Mg^2＋ concentration is over 20 g·L^-1 after 2 months in column bioleaching, the redox potential of leachate keeps stable, much less than that when Mg2＋ concentration is below 20 g·L^-1. Meanwhile, the extractions of Cu^2＋ and Co^2＋ from chalcopyrite with carrollite obviously inhibited by Mg^2＋ concentration of over 20 g·L^-1 were investigated. The extraction of cobalt depends on chalcopyrite dissolved in column reactor. The growth and oxidation activity of bacteria are affected by high Mg^2＋ concentration （〉20 g·L^-1） in leachate of column reactor. As the rate of gangue dissolution depends on the amount of sulfuric acid, the decrease of the particle size relates to the increase of the total particle surface area and acid consumption. Therefore, the operation of pre-leaching for magnesium removal is not the most effective and economical way to solve the problem of magnesium-rich gangue minerals dissolution.

关键词： Magnesium-rich Column bioleaching Chalcopyrite Carrollite

Experimental research on the instability propagation characteristics of liquid kerosene rotating detonation wave

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Defence Technology（防务技术） 2020年第6期16卷 1106-1115页

作者： Quan Zheng Hao-long Meng Chun-sheng weng Yu-wen Wu wen-kang Feng Ming-liang Wu National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing210094China

In order to study the instability propagation characteristics of the liquid kerosene rotating detonation wave(RDW),a series of experimental tests were carried out on the rotating detonation combustor(RDC)with *** fuel and oxidizer are room-temperature liquid kerosene and preheated oxygenenriched air,*** experimental tests keep the equivalence ratio of 0.81 and the oxygen mass fraction of 35%unchanged,and the total mass flow rate is maintained at about 1000 g/s,changing the total temperature of the oxygen-enriched air from 620 K to 860 *** different types of instability were observed in the experiments:temporal and spatial instability,mode transition and *** interaction between RDW and supply plenum may be the main reason for the fluctuations of detonation wave velocity and pressure peaks with ***,the inconsistent mixing of fuel and oxidizer at different circumferential positions is related to RDW oscillate *** phenomenon of single-double-single wave transition is *** the transition,the initial RDW weakens until disappears,and the compression wave strengthens until it becomes a new RDWand propagates *** increased deflagration between the detonation products and the fresh gas layer caused by excessively high temperature is one of the reasons for the RDC quenching and re-initiation.

关键词： Rotating detonation wave Liquid kerosene Oxygen-enriched air Instability propagation characteristics Compression wave

Chemical leaching mechanism of chalcopyrite with difference mineralization

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Rare Metals 2013年第1期32卷 63-66页

作者： Jing Bai Jian-kang wen Song-Tao Huang Biao Wu National Engineering Laboratory of Biohydrometallury General Research Institute for Nonferrous Metals

This paper presents the effect of mineralization on chalcopyrite chemical leaching in very simple H2SO4 solution systems at pH 1.0, with 5 % chalcopyrite con- centrate at 65 ~C. The copper extractions after 12 days leaching of marine volcanic and porphyry chalcopyrite were 85.7 and 66.6 %, respectively. It was found that sulphur element formed on the surface of two samples as a result of XRD and SEM-EDAX, which was very porous that did not inhibit chemical leaching reaction. Meanwhile, （Cu, Fe）12As4S13 formed on the surface of porphyry type chalcopyrite, which may cause low leaching ratio of por- phyry type chalcopyrite as passivation. （Cu, Fe）12As4S13 may be one kind of the polysulphide compounds.

关键词： Chalcopyrite Chemical leaching Passivation Mineralization