Table of Content

20 August 2014, Volume 14 Issue 4

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流动与传递

Comparison of Flow Characteristics of Draft Tube-lifted Gas-Solid Air Loop Reactor with Free Fluidized Bed Reactor

SHEN Zhi-yuan YANG Li-jun LIU Meng-xi LU Chun-xi

. 2014, 14(4):  541-548. 

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Flow characteristics were investigated and compared between a draft tube-lifted gas-solid air loop reactor (GSALR) and a free fluidized bed reactor (FFB) based on the same operating conditions. The results show that the radial heterogeneity index in the draft tube region of GSALR is smaller 27%~36% than that in FFB at axial height h=112~512 mm. The local heterogeneity index is smaller 20%~59% and the overall heterogeneity index is smaller 17%~43% in the draft tube region of GSALR than those in FFB. Compared with FFB, GSALR is superior in the fluidization quality. Gas back mixing characteristics were studied in GSALR and FFB, and the one-dimensional axial dispersion model was established. The tracer gas concentration and axial diffusion coefficient are smaller in the draft tube region of GSALR than those in FFB. The absolute value of Peclet number is smaller 12%~58% in FFB than that in the draft tube region of GSALR when the superficial gas velocity is 0.2~0.4 m/s, demonstrating that the gas back mixing is weaker in the region. The upward macro-flow in the draft tube region could effectively restrain the axial gas-back mixing.

Flow and Entrainment Characteristics of Jet from Different Shape Nozzles

YU Yan-fang LI Chun-xiao MENG Hui-bo WANG Yan-fen SONG Ming-yuan WU Jian-hua

. 2014, 14(4):  549-555. 

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The entrainment characteristics of five different shape nozzles, circular, elliptic, square, cross and triangular, were simulated by using CFD ANSYS Fluent 6.3, their jet axial velocity and streamwise velocity contour maps under different Reynolds number values were analyzed and compared. The results showed that the jet axial velocity decayed by power exponent with the axial location, and the jet axial velocity values of triangular nozzle were the maximum among the five nozzles. The multiple linear relationships between jet penetration and Reynolds number and Froude number were regressed. It could be seen from the contour maps of streamwise velocity of five different nozzles that the shapes of jet cross-section were in accordance with corresponding shape nozzle in jet initial region, and the border of jet cross-section was transformed gradually into circular shape with increasing of the axial location. The half-width of the jet axial velocity increased linearly with increasing of the axial position. Moreover jet entrainment and mixing characteristics were analyzed by comparing half-velocity widths and entrainment ratios of five different nozzle shapes. The jet entrainment ratio of triangular shape nozzle was 1.92~2.32 times than that of cross shape nozzle.

Axial Distribution and Development of Solids Hold-up in a Fluidized Bed-Riser Coupled Reactor

CUI Gang LIU Meng-xi LU Chun-xi

. 2014, 14(4):  556-561. 

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The axial distributions of cross-sectional averaged density of FCC particles were measured in a large scale cold model turbulent fluidized bed-riser coupled reactor. The results showed that the flow behaviors of FCC particles in the coupled reactor presented fairly different characteristics with changing of superficial gas velocity. The flow behavior could be divided into three types based on superficial gas velocity. A steady flow was observed in the reactor for superficial gas velocity below 0.58 m/s, while a back-mixing zone in the top of the riser appeared as the superficial gas velocity varied between 0.7~1.04 m/s. When superficial gas velocity was greater than 1.16 m/s, the riser concentration reforming and accelerating zones occurred in the bottom of the reactor, with the fully developed zone appearing in the middle of the reactor, and the back-mixing zone was enhanced in the top of the reactor. The cross-sectional averaged density increased with the increase of superficial gas velocity. The static bed height had no obvious effect on the axial local solids hold-up in different cross-sections. The critical superficial gas velocity responsible for the appearance of the riser concentration reforming zone was smaller for the higher static bed height than that for the lower static bed height. Furthermore, an empirical model for estimating the axial distribution of averaged cross-sectional solids hold-up was established based on the experimental data and theoretical analysis, respectively, which agreed with the experimental data.

Prediction of Ultrasonic Attenuation in Liquid-Solid Particulate Two-phase System with Monte Carlo Method

GUO Pan-pan SU Ming-xu CHEN Li CAI Xiao-shu

. 2014, 14(4):  562-567. 

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For the study of complex sound scattering phenomena, the Monte Carlo method was investigated to establish a novel particle size characterization model in concentrated particulate two-phase flow. Starting from the single particle scattering theory, the numerical simulation was carried out to predict the acoustic attenuation characteristics in the two-phase system of glass bead/water with different particle sizes, concentrations and ultrasonic frequencies. Through the comparison of ECAH model of single scattering theory, it was found that they met each other well at the concentration of 1%(j), while clear divergence occurred with the increase of the concentration. At the same time, the simulation results were compared with experiment result from literature. It was shown that the attenuation in the particle radii of 35 and 90 mm in two-phase system predicted by Monte Carlo method agreed well with experiments. The proposed Monte Carlo method could be used for calculating the attenuation in high particle volume concentration of 50% and numerical modeling of particle size measurement in the complex scattering condition.

Study on Liquid Hold-up of Rotating Zigzag Bed

LU Yong-sheng LI Yu-min YU Yun-liang LIU Xue-jun WANG Hong-jun

. 2014, 14(4):  568-572. 

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A mathematical model on the liquid hold-up of a rotating zigzag bed (RZB) was proposed on the basis of division of the bed into several liquid-flow regions, from which the flowing time of liquid film on the walls of stationary and rotating baffles and flowing time of liquid droplets in the gap between the stationary and rotating baffles were calculated. Using air-water system the experiment was carried out in the bed with a rotor of 300 mm diameter and 51 mm height to measure the liquid hold-up with and without gas flow. The model parameters were obtained by regression based on the experimental data. The results showed that the liquid hold-up increased with increasing of liquid flow rate and gas flow rate, but decreased with increasing of rotor speed, and the influence of the gas flow rate decreased significantly at high rotor speeds. The liquid hold-up of RZB without gas flow was 2.35%~3.68%, which was 1.32~2.06 times of the common wire mesh rotating packing bed.

反应与分离

Extraction of Valuable Metals from Smelting Slag of Carbon Ferrochrome by (NH4)2SO4 Roasting and Leaching

FENG Qiang CUI Wen-wen ZHANG Ying ZHENG Shi-li WEI Chang FAN Gang WANG Shao-na

. 2014, 14(4):  573-579. 

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The carbon ferrochrome smelting slag was roasted with (NH4)2SO4 and leached for recovery of valuable metals. The effects of roasting temperature, dosage of (NH4)2SO4 and roasting time on the leaching rate of valuable metals and phase transformation were studied. The TGA-DSC results indicated that obvious mass loss occurred between 250 and 450℃, which reached 65.5% due to the release of NH3, H2O, SO3 and volatilization of (NH4)2SO4. The optimum roasting conditions were obtained as mass ratio of (NH4)2SO4 to slag 5:1, roasting temperature 350℃ and roasting time 3.5 h. In the roasting, the valuable metals were transformed into their corresponding ammonium metal sulfates, and they coexisted with the decomposed products of ammonium sulfate. When the roasted slag obtained at the optimum roasting conditions was leached for 1 h at 90℃, the leaching rate of Mg, Al, Cr and Fe reached 92%, 80%, 82% and 93%, respectively. It was estimated that the flaky aggregate of ammonium metal sulfates should probably be the resistance preventing the reaction of the interior of carbon ferrochrome smelting slag with (NH4)2SO4.

Flotation and Leaching Process of a Copper Oxide Ore from Turkey

SONG Chao GAO Li-kun DAI Hui-xin QI Peng

. 2014, 14(4):  580-586. 

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A copper oxide ore from Turkey with copper grade 2.09% was treated by flotation and leaching. The ore contained useful minerals of malachite, azurite and chrysocolla, as well as a small amount of copper sulphide, and had high oxidation rate and fine dissemination of useful minerals, which was easily muddy. The copper sulphide and part of malachite and azurite were enriched by flotation. The concentrate grade of copper from flotation was 25.04% with the recovery rate of 57.25%. The azurite and chrysocolla that remained in the tailings were leached by sulfuric acid, and the grade of copper decreased from 0.94% to 0.05%, the leaching rate of copper was 94.68%, leading to the high recovery rate of useful minerals.

Separation of Polymethylene Polyphenyl Polyisocyanate (PMPPI) from the PMPPI-Chlorobenzene Pyrolysis Liquid Using Molecular Distillation

LONG Shi-liang CAO Yan LI Hui-quan CHEN Jia-qiang WANG Li-guo HUANG Ke-lin

. 2014, 14(4):  587-592. 

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Molecular distillation was used to separate polymethylene polyphenyl polyisocyanate (PMPPI) from PMPPI-chlorobenzene pyrolysis liquid via orthogonal experiments using an OA25(45) design, the optimal separation conditions of the simulated PMPPI- chlorobenzene solution were determined as feed flow rate 2 mL/min, distillation temperature 100℃, wiper rotating speed 120 r/min and distillation pressure 4.0 kPa. Under the optimal conditions, the purity of PMPPI reached as high as 99.65%. Finally, the real PMPPI- chlorobenzene pyrolysis liquid was separated using the above optimal conditions, chlorobenzene could not be detected in the final product with HPLC analysis, indicating that the purity of PMPPI approached to 100%.

Magnetic Reduction Roasting and Magnetic Separation of Oolitic Iron Ore

CHEN Li-qun CHEN Min YAN Hao-tian CUI Shaung-shuang ZHANG Yan-juan

. 2014, 14(4):  593-598. 

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Magnetic reduction roasting and low intensity magnetic separation accompanied at different temperatures were carried out for the beneficiation of an oolitic iron ore from in the west of Hubei Province. The effects of magnetic roasting time on magnetic separation, phase transformation of iron minerals and composition of oolitic iron ore were investigated with microscopic observation and statistic data of roasted particles, combined with XRD analysis. The results indicate that the mineral particles containing iron are mainly composed of different oolitic concentric shells from 1 to 2 mm and closely enwrapped tiny particles at about 10 mm. An iron ore concentrate with total iron content of 56.34% at the recovery rate of 88.05% can be obtained by magnetic tube separation under the roasting conditions of 800℃ for 60 min and slight reduction atmosphere for separation. The effect of roasting time on magnetization roasting is obvious. The magnetic roasting of oolitic iron ore can be accomplished in iron phase transformation, but the configuration of oolitic particles has not changed. Magnetization transformation is mainly controlled by solid-state diffusion from surface to interior. The reduction degree increases with roasting time. The phase transformation of wustite FeO hardly appears in less than 30 min, and a little FeO exists after then. Fe2SiO4 is seldom confirmed experimentally. The minerals containing P and Si have changed to some extent in phase transformation in different periods of roasting time.

Separation of Zn with As from Water Leaching Solution of High Arsenic Content Flue Dust

WANG Qian-qian LIU Jing-chong ZHU Yuan-yuan GUO Jiu-ji ZHAO Wei ZHAO Hui YU Ping QI Tao

. 2014, 14(4):  599-604. 

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The separation process of Zn with As from the water leaching solution of high arsenic content flue dust was studied. Based on the results of ferric sulfate route and calcium oxide route, a ferric sulfate-calcium oxide coupled separation route of Zn with As was proposed. The results show that under the optimal conditions of pH value 2, molar ratio of H2O2/As3+ 1.3:1, Fe3+/As5+ 1:1.5, Ca2+/As5+ 1.5:1, reaction temperature 70℃ and time 1.5 h, the As removal rate reaches more than 80% while the loss of Zn nearly is zero. The effective separation of Zn with As has been achieved in this new route.

Deacidification of Vacuum Gas Oil by Using Ethanolamine Based on Principle of Ionic Switch

WANG Yu-hai FU Yu'e

. 2014, 14(4):  605-609. 

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According to the principle of ionic switch, the deacidification process of vacuum gas oil was studied by using ethanolamine ethanol solution. The process conditions and reaction kinetics were obtained. It was showed that under the conditions of ratio of deacidification agent to oil at 4:15, reaction temperature 60℃ and reaction time 50 min, the deacidification rate of vacuum gas oil could reach more than 70%. After the deacidification, the treated oil quality was significantly increased, the acid value of naphthenic acid obtained from the treated oil was 157 mg KOH/g. The conditions of deacidification process were mild without emulsification phenomenon, waste water and residue, and the deacidification agent could be reused, which shows a good economy.

过程与工艺

Treatment of Turpentine Processing Wastewater by Combined Process of Fe/C Microelectrolysis-Fenton Oxidation-Coagulation Sedimentation-Biochemical Technology

NIE Li-jun ZHOU Ru-jin ZHONG Hua-wen QIU Song-shan MI Shi-wu

. 2014, 14(4):  610-616. 

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The combined process of Fe/C microelectrolysis-Fenton oxidation-coagulation sedimentation and biochemical technology is adopted to treat the turpentine processing wastewater. Firstly, through the signal factor and orthogonal experiments, the optimal operating conditions of Fe/C microelectrolysis, Fenton oxidation and coagulation sedimentation are determined, and the removal efficiency of chemical oxygen demand (COD) and the change of BOD5/CODCr value are investigated. The improvement of biodegradability of the wastewater is then discussed. Secondly, by the treatment of biological aeration filter (BAF), the influential parameters can be defined, and the feasibility of wastewater discharging standard is then investigated. The results show that when the dosage of iron chips is 100 g/L, Fe/C ratio 1.5:1, dosage of H2O2 40 mL/L and dosage of PAM 8 mg/L, respectively, the COD value is 200~450 mg/L, the COD removal efficiency 98% and the BOD5/CODCr value can be improved from 0.13 to 0.64, meeting the requirements for the successive biochemical treatment unit. Thus BAF is used for the biochemical treatment unit. The indices of COD, fats and oils, and chroma of treated water are 50~90, 3~10 and 30~50 mg/L, respectively, under the conditions of hydraulic retention time for 5 h and concentration of DO at 2~3 mg/L. The output water quality meets the first grade standard in Comprehensive Discharging Standard for Wastewater (GB8978-1996).

Release Models of Chloride and Alkali-metal Hydroxides during Coal and Biomass Combustion and Their Effects on NO Emission

KANG Hong Sun Shu-feng GUO Xiao-feng WEI Xiao-lin;

. 2014, 14(4):  617-623. 

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Based on the chemical kinetics, a model is proposed to describe the release rate of chloride and alkali-metal hydroxides in combustion of biomass and coal, which is validated through the comparison of calculating and experimental results of chloride. In the simulation of biomass reburning, the model is extended into detailed reaction mechanism, which is applied to analyze the effects of chloride and alkali-metal hydroxides on NO reduction rate at different temperatures and concentrations. The results show that the effect of alkali-metal hydroxides is more obvious than that of chloride; the effect of NaOH is more obvious than that of KOH. These compounds may affect NO emission via the effect on the concentrations of some radicals. Taking Datong coal as an example, the effects of temperature (T) and concentration (C) of alkali-metal hydroxides on the NO reduction rate (hNO) can be expressed as hNO=AT-BT2+DC-E.

Experiment and Mathematical Simulation on Magnetization Reduction Roasting of Limonite Particles with CO at Low Temperature

DAI Tao GONG Zhi-jun LI Bao-wei WU Wen-fei

. 2014, 14(4):  624-630. 

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The magnetization reduction roasting process of limonite particles in conversion of Fe2O3 into Fe3O4 with CO at low temperature (673~893 K) was studied by experiment and mathematical simulation. The established model included the heat transfer and mass transfer equations in the particles, and a changing pore of random pore reduction equation. By numerical simulation and experiment, the reduction degree data of limonite particles with time under different CO concentrations and temperatures were obtained. The results showed that the reduction process was controlled by chemical reaction, gas diffusion and particle pore changing. The limonite particles with the size of 100 mm at the porosity of 0.5 and CO concentration of 10%(mol) were reduced within 15 min at 673 K when the reduction degree was 1.

Influence of Particle Size on the Performance of Cu-based Oxygen Carrier

ZHENG Xiao-ming SU Qing-quan MI Wan-liang SHAO Jia-xing PAN Lu

. 2014, 14(4):  631-636. 

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Based on a new chemical looping combustion (CLC) process, the effects of sizes of oxygen carrier particles, Cu powder and γ-Al2O3 powder on the performances of oxygen carrier were investigated in a fixed bed reactor. The results show that reduction and oxidation rates of oxygen carrier increase as the size of Cu powder decreases. For Cu powder with the mean size below 63 mm, the reduction and oxidation rates of oxygen carrier reach above 95% and 93%, respectively. In the reduction step, a small amount of CH4 is generated, and it decreases as the size of Cu powder decreases. For Cu powder with the mean size below 32 mm, the amount of CH4 is decreased to below 1%. When the size of oxygen carrier is close to the size of γ-Al2O3, the performances of oxygen carrier are significantly reduced. Only when the particle size of γ-Al2O3 is significantly smaller than the particle size of oxygen carrier, the γ-Al2O3 can effectively disperse the particles of active component, and then inhibit its sintering.

Modeling and Numerical Simulation on Magnetization Reduction Characteristics of Porous Limonite

ZHU Chao GONG Zhi-jun LI Bao-wei WU Wen-fei

. 2014, 14(4):  637-642. 

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Based on the actual situation of magnetization reduction roasting of limonite particles in a fluidized bed, a microscopic kinetics model of gas-solid reduction reaction was established. The model included the unsteady heat transfer equation within the particles, gas transport equation in pores and heterogeneous chemical kinetic equation based on the improved random pore model describing the pore size distribution. Finite difference method with implicit formulation was applied to solve the set of governing equations. The results of numerical simulation were consistent with the experimental TG results. It was indicated that if the temperature was raised 50 K, the reduction time would be shortened by 36%. The roasting reactivity was nearly proportional to the CO concentration. The roasting time could be shortened to 60 s when the roasting temperature was 870 K and CO concentration 2.624 mol/m3.

生化工程专栏

Simulation and Pilot Test of Xylose Production Using Oxalic Acid-saturated Continuous Steam Explosion of Corncob

PAN Yu-qing ZHANG Hong-jia QIU Xue-liang OUYANG Xian-hong WANG Wen-ya LI Shuang-xi ZHANg Qiu-xiang YUAN Qi-peng

. 2014, 14(4):  643-648. 

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The effects of steam explosion parameters of oxalic acid-saturated corncob on xylose production and the effect of enzymatic hydrolysis of resulting explosive residue on glucose were investigated. The results indicate that the optimized conditions of steam explosion were pressure 1.0 MPa, time 5 min and oxalic acid/dried corncob ratio 45 g/kg. Based on the optimized conditions, a process model of oxalic acid-saturated continuous steam explosion (OSCSE) was developed by SPSS statistics and the correlation coefficient (R2) of equations was greater than 0.9, which indicated that they can be applied to predict the productivity of xylose. The pilot scale test showed that 415.50 g xylose could be produced with 3.81 kg dried corncob, i.e., 1 t of xylose could be produced from 9.17 t of dried corncob, which meets the demand of industrial production. The enzymatic hydrolysis of explosive residue indicated that the glucose productivity from OSCSE was higher than that from H2O-saturated steam explosion of corncob and that from the control by 32.30% and 214.8%, respectively.

Expression and Anti-agiogenesis Activity of Human and Mouse Endostatin

YANG Yi-jin LU Jun-jia QIN Xia CHANG Rong-ni LAI Qing-niao HUA Rong FANG Ling WU Hua-yu HOU Wei WU Fei-xiang XIE Tong YUAN Zhi-gang SHU Wei

. 2014, 14(4):  649-654. 

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Human endostatin (HE) and mouse endostatin (ME) cDNA sequences were determined based on the reports and NCBI database. Their 554 bp HE and 565bp ME cDNA sequences were obtained through DNA synthesis, respectively. Prokaryotic expression plasmids pGEX-4T1-HE and pET-32a-ME with different protein labels of GST and TrxA were constructed, then expressed through induction in Escherichia coli BL21(DE3), HE and ME recombinant proteins were obtained and their anti-angiogenesis activity was analyzed by chick chorioallantoic membrane (CAM) test. The human and mouse endostatin gene expression vectors with different labels were successfully constructed and used in induced expression in Escherichia coli. CAM testing results indicated that the purified refolded recombinant protein had a strong anti-angiogenesis activity. The human and mouse ES recombinant proteins were obtained successfully. TrxA and GST labels showed no difference in the increase of soluble expression of recombinant ES, both of the recombinant protein with different labels mainly existed in inclusion body.

Effects of Calcium Ion on the Morphology of Rhizopus oryzae and Production of L-Lactic Acid

WU Yu-jie HONG Lu SUN Xiao-long FU Yong-qian

. 2014, 14(4):  655-659. 

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The effects of calcium ion on morphology of Rhizopus oryzae pellets during preculture and L-lactic acid production in fermentation were studied. The results showed that the addition of calcium ion could induce the pellet formation. The smaller pellets precultured with low concentration of soluble calcium (CaCl2) were beneficial to the production of L-lactic acid. By contrast, the larger pellets (1.5 mm) precultured with high concentration of insoluble calcium (CaCO3), except 8.0 g/L CaCO3, were beneficial to the production of L-lactic acid, the highest L-lactic acid productivities of 1.22 g/(L×h) and 58.6 g/L were achieved, which was better than those with CaCl2 at 1.02 g/(L×h) and 57.2 g/L. The excessive CaCO3 could envelope the pellets, and decreased its productivity when precultured with 8.0 g/L CaCO3.

Effect of Sucrose and Glucose as Cosubstrate on 1,3-Propanediol Fermentation by Recombinant Klebsiella pneumoniae

WU Jia-xin WANG Feng-huan WANG Zheng TAN Tian-wei LIU Pei-yi

. 2014, 14(4):  660-663. 

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The effects of glucose and sucrose as two kinds of cosubstrate on fed-batch fermentation of 1,3-propanediol by recombinant Klebsiella pneumoniae were investigated, and the scale-up of fermentation technology and optimization of feeding strategy also studied. The results showed that glucose as cosubstrate was better than sucrose. The final yield and productivity of 1,3-propanediol were 85.2 g/L and 0.63 mol/mol in 30 L fermentor by exponential feeding strategy with glucose, respectively. Compared with only glycerol as the carbon source, the yield and productivity of 1,3- propanediol were raised by 37.35% and 25.00%, respectively.

材料工程专栏

Viscosity and Melting Property of Low Titanium-containing Blast Furnace Slag

YUAN Xiang ZHANG Jian-liang MAO Rui LIU Zheng-jian ZHU Guang-yue

. 2014, 14(4):  664-670. 

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RTW-10 integrated instrument for measurement of melt properties was used to measure the variation of viscosity of CaO-SiO2-MgO-Al2O3-TiO2 slag system with temperature, its melting temperature calculated, and the high-temperature metallurgical properties of the slag were studied. The results showed that when TiO2 content in the slag increased from 1.0% to 2.2%, both the melting temperature and viscosity decreased. With increasing of the Al2O3 content, the melting temperature and viscosity of the slag increased, but in high temperature range, the slag viscosity was less than 0.7 Pa·s, it still had good fluidity. When the MgO content increased from 8.5% to 10.5%, the slag melting temperature decreased, but the slag viscosity slightly changed. For industrial production with lower TiO2 content blast furnace slag, increasing the use of titanium-containing raw material could provide the protection of furnace operation.

Preparation of Cationic CPDAC Gel Microspheres via Inverse Suspension Polymerization and Their Adsorption Characteristics to Toxic Anion Species

XU Rui GAO Bao-jiao YANG Qing

. 2014, 14(4):  671-676. 

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The crosslinking copolymerization (CP) of acryloxyethyltrimethyl ammonium chloride (DAC) and N,N′-methylene bisacrylamide (MBA) was performed via inverse suspension polymerization method, and 200~300 mm CPDAC gel microspheres were prepared with cyclohexane as dispersion medium and Span-60 as dispersant. The effects of main factors on the balling performance and grain diameter of CPDAC were examined, and CPDAC characterized. The adsorption (anion exchange) characteristics of CPDAC were studied. The results show that in order to prepare CPDAC, the dispersion phase (water) must be added in the manner of dropwise adding, Span-60 is a suitable dispersant, and the grain diameter of CPDAC decreases with increasing of the amount of Span-60. The volume ratio of oil phase to water phase can not be smaller than 2:1, the grain diameter of CPDAC decreases with increasing of the volume ratio. The agitating rate can not be below 250 r/min, the grain diameter decreases with increasing of the rate. Through the strong ion exchange action and electrostatic interaction, CPDAC possess strong adsorption to four anionic species, CrO42-, MoO42- and acidic dyes Reactive Brilliant Red and Reactive Yellow, with the adsorption capacities of 213, 275, 1850 and 1690 mg/g, respectively. The adsorption capacity decreases with increasing of temperature.

Adsorption of Cd(II) on Polyamino-functionalized SBA-15 Material

ZHANG Chun-hua CHEN Man-sheng XU Jin-sheng YI Zheng-ji LI Wei KUANG Yun-fei

. 2014, 14(4):  677-682. 

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The triamino-modified porous SBA-15 (3N-SBA-15) adsorbent was prepared by posting-graft hydrothermal synthesis with Pluronic P123 as template agent and tetraethyl orthosilicate as the silicon source, and characterized. The effects of experimental conditions such as contact time, pH value, initial Cd2+ concentration and temperature on the adsorption were studied. The adsorptive results showed that the adsorption equilibrium well fitted to Langmuir equation, the maximum adsorption capacity of Cd2+ onto 3N-SBA-15 was 0.93 at 20℃, 0.97 at 30℃ and 1.05 mmol/g at 40℃. And the adsorption equilibrium reached within 90 min when 150 mg/L adsorbent was added into 50 mL solution containing of 100 mg/L Cd2+ at pH 4.5, the maximum adsorption capacity of 3N-SBA-15 was 1.05 mmol/g. The thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Moreover, its adsorption mechanism and regeneration of 3N-SBA-15 were also explored.

Catalytic Performance of N-Hydroxyphthalimide-immobilized Cross-linked Polystyrene Microspheres in Oxidation of Toluene and Cyclohexanol

HUANG Jian-long GAO Bao-jiao YANG Xiao-lin

. 2014, 14(4):  683-688. 

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The immobilized N-hydroxyphthalimide (NHPI) catalyst was prepared with cross-linked polystyrene (CPS) microspheres as matrix by molecular design. The chloromethylated cross-linked polystyrene (CMCPS) microspheres were first prepared, and then phthalic anhydride (PA) was bonded onto them through the esterification reaction between the chloromethyl groups on the microspheres and carboxyl group of trimellitic anhydride (TMA), obtaining CPS-PA microspheres. Finally, the bonded PA reacted with hydroxylamine hydrochloride, resulting in CPS-NHPI microspheres, on which NHPI groups were immobilized. The CPS-NHPI microspheres were characterized, and used in the oxidation of toluene and cyclohexanol with molecular oxygen, respectively. The catalytic activity of CPS-NHPI was examined, and catalytic oxidation mechanism investigated. The results show that the reaction of CMCPS microspheres with TMA is a key step, which can be carried out smoothly with triethylamine as acid-binding agent and polar solvent N,N-dimethylacetamide at 110℃, the conversion rate of chloromethyl on CMCPS microspheres can reaches 73%, and the CPS-NHPI microspheres with a NHPI immobilized capacity of 2.25 mmol/g can be gained. The combinatorial catalyst system constituted by CPS-NHPI microspheres and a little of Co(OAc)2 displays fine catalytic activity in the oxidation reactions of toluene and cyclohexanol with molecular oxygen as oxidant, and the catalytic oxidations may undergo the mechanism of free radical chain reaction.

Synthesis and Upconversion Luminescence Properties of NaY(WO4)2:Dy3+ Phosphor

WANG Ya-jing SHI Zhong-xiang LIU Xiao-chuan XIAO Lin-jiu XIE Ying;

. 2014, 14(4):  689-693. 

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Single Dy3+ doped NaY(WO4)2 up-conversion luminescence phosphor was prepared by hydrothermal method, and its properties were characterized by XRD and SEM. The effects of doping concentration of Dy3+, pH value, reaction temperature and roasting temperature on its structure, morphology and luminescence properties were investigated. The optimum synthesis conditions of NaY(WO4)2 with the best luminescent properties were obtained as the concentration of Dy3+ at 0.5%, pH=8, reaction temperature 180℃ and roasting temperature 800℃. Under 776 nm excitation of NaY(WO4)2:Dy3+, the blue emission peak at 480 nm and yellow one at 577 nm were observed. The blue emitting light resulted from the transition of 4F9/2→6H15/2 of Dy3+, and yellow one from the transition of 4F9/2→6H13/2 of Dy3+.

综述

Research Advances in Electrochemical Window of Ionic Liquids

QI Can-can HUA Yi-xin XU Cun-ying LI Jian ZHANG Qi-bo LI Yan

. 2014, 14(4):  694-707. 

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Based on the status quo of the application of ionic liquids and their electrochemical window, a large number of electrochemical window data from domestic and foreign research sources of ionic liquids are summarized, including chloroaluminate systems, imidazolium, quaternary ammonium salts, etc. The electrochemical windows of ionic liquids depend on their cations and anions, working electrodes and reference electrodes. Through analyzing the above factors, it is obtained that the cathodic limiting potential of ionic liquids decreases in the following order? ammonium " phosphonium > pyrrolidinium > piperidinium " morpholinium > azepanium " imidazolium > sulfonium>pyridinium. The anodic limiting potential of

Research Progress in Systematic Energy Saving-oriented Monitoring and Simulation Technologies of Metallurgical Processes

NAN Jian RAO Zheng-hua LIU Xiao-jun HE Hui-min LIAO Sheng-ming

. 2014, 14(4):  708-714. 

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The current advances in the systematic energy saving-oriented monitoring and simulation technologies of metallurgical processes, including the research and application of energy management system, numerical simulation method in metallurgical processes, are reviewed. The process simulation of metallurgical processes, computational fluid dynamics (CFD) simulation of key metallurgical equipment and their integration are mainly analyzed, and the application and limitation of numerical simulation technology for systematic energy saving of metallurgical processes discussed. The results show that the process simulation can analyze parameter variation of a whole metallurgical production process, while ignoring physical characteristics of the unit operation and space changes. CFD simulation can be used to analyze the mechanism and optimize the operating parameters of single metallurgical equipment, however it can not realize the relevance of operating parameters between upper and lower processes. The integration of process and CFD simulations by using time series method can combine the advantages of both, which will be an important direction in investigation of the systematic energy saving of metallurgical processes.

Research Progress in Replacement of CH4 from Methane Hydrate with CO2

ZHANG Xue-Min LI Jin-ping WU Qing-bai WANG Chun-long NAN Jun-hu

. 2014, 14(4):  715-720. 

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The current exploitation methods of natural gas hydrate domestically and oversea were comprehensively summarized with focus on the research progress in the exploitation methods of CO2 replacement. Then the feasibility of replacement between CO2 and CH4 hydrate was theoretically analyzed based on reaction kinetics and thermodynamics, respectively. However, previous research mainly focused on the free saturated water system, and natural gas hydrate distributed in sediment of seafloor and permafrost region. Therefore, it is necessary to study the dynamic process and reveal the intrinsic mechanism of replacement reaction. Finally, the potential problems and development direction in the future were point out in research on exploitation methods of CO2 replacement of natural gas hydrate.