Table of Content

20 February 2011, Volume 11 Issue 1

Previous Issue    Next Issue

流动与传递

Turbulent Characteristics of a Novel Circulating Jet Mixer

YU Yan-fang WU Jian-hua MENG Hui-bo

. 2011, 11(1):  1-8. 

Asbtract ( )   PDF (620KB) ( )  

Related Articles | Metrics

SST k-w turbulence model was employed to simulate the turbulent flow field of a novel circulating jet mixer. The similarity of confined zone jet and the decay of jet axial velocity at various baffle lengths were carried out. The decay of dimensionless jet axial velocity by simulation was in good accordance with theoretical curve for free turbulent jet. The fluid zone in the jet mixer was divided into four sub-regions based on the three-dimension velocities. The fluid circulating flow in the novel jet mixer was studied by vorticity and the average vorticity áw? with different axial positions and phase planes. The results show that the maximum value of áw? is 11.22 at z/H=0.25. áw? is positive at qp<20o, while at other qp it is negative. The maximum value of áw? is 27.22 which is located at qp=16o, and the minimum value of áw? is -100.66 at qp=20o. The simulation result of shear rate reveals that the larger value is located in the trailing vortex. The factors for enhancing the mixing effect are put forward.

Effect of Sieve Plate Structure on Gas Cap Height and Local Gas Holdup in a Multistage Bubble Column Reactor

QIN Ling JIN Hai-bo; YANG Suo-he HE Guang-xiang ZHU Jian-hua

. 2011, 11(1):  9-14. 

Asbtract ( )   PDF (245KB) ( )  

Related Articles | Metrics

The effect of sieve plate structure on the gas cap height and local gas holdup in a f300 mm multistage bubble column was studied using differential-pressure method and double-sensor conductivity probe. The experimental results show that the gas cap height increases with the increase of superficial gas velocity, ug, and decrease of opening area of the sieve plates. The gas cap height increases from 0.01 to 0.06 m while ug increases from 0.04 to 0.24 m/s. Moreover, the radial distribution of gas holdup in the reactor is similar to that in a regular bubble column. The average gas holdups above and under the plate increase with the increase of ug. For the axial distribution of gas holdups, when ug is about 0.027 m/s, the gas holdups above and under the plate are all around 0.05. But when ug becomes 0.11 m/s, the gas holdup under the plate is about 0.3~0.35, which is much higher than the one above plate with around 0.25~0.3.

Numerical Simulation of Mixing Performance in Seed Precipitation Tank with an Improved Intermig Impeller

ZHAO Hong-liang ZHANG Ting-an ZHANG Chao LIU Yan ZHAO Qiu-yue WANG Shu-chan DOU Zhi-he

. 2011, 11(1):  15-19. 

Asbtract ( )   PDF (779KB) ( )  

Related Articles | Metrics

Seed precipitation tank with a new-style improved Intermig impeller was numerically simulated by using the commercial software Fluent 12.0 on parallel computing graphic workstation. The suspension of Al(OH)3 particles and power consumption in the alumina seed precipitator under different conditions of the impeller off-bottom clearance height (C) and blade diameter (D) were numerically simulated by using realizable k-ε turbulence, Eulerian-Eulerian multiphase and multi-reference frame rotating models. The numerical simulation results showed that at a constant rotate speed, enlarging D was good for suspension of Al(OH)3 particles, but bigger D resulted in more power consumption. The optimal value of D/T was 0.6, T was the tank diameter. Too big or too small C was not conducive to the suspension of Al(OH)3 particles, and C had little effect on the stirring power. The optimal value of C/D was 0.55.

Numerical Simulation of Three-phase Flow in an Oxygen Top-blown Convertor

DONG Kai ZHU Rong; HE Chun-lai; WEI Xin-yan LIU Fu-hai

. 2011, 11(1):  20-25. 

Asbtract ( )   PDF (1065KB) ( )  

Related Articles | Metrics

The impingement of supersonic oxygen jets on molten steel and slag in an 85 t top-blown convertor bath was studied and the flow field of molten bath analyzed. The results show that with the oxygen lance rising, the diameters of cavities created by jets in the molten slag and steel increase, whilst the depths decrease. With the lance height rising from 1.2 to 1.8 m, the diameter of cavity in the molten steel increases from 1.359 to 1.566 m, whilst the depth decreases from 0.187 to 0.157 m. At the same time, the maximum velocity of liquid steel decreases from 0.48 to 0.27 m/s 0.2 m under the molten steel surface, whilst the maximum velocity of liquid steel increases from 0.06 to 0.09 m/s 0.8 m under the molten steel surface. High lance position has a positive effect on the homogeneous distribution of liquid steel velocity.

Mathematical Simulation for Velocity and Temperature Fields of Molten Steel in a 5-strand Tundish

ZHONG Liang-cai WANG Ming-an ZHOU Xiao-bin LIU Le-dong TENG Li-hong

. 2011, 11(1):  26-30. 

Asbtract ( )   PDF (480KB) ( )  

Related Articles | Metrics

Velocity and temperature fields of molten steel in a 5-strand tundish with different baffles were investigated by mathematical simulation. The calculation results showed that liquid steel directly moved to the outlets of tundish with original baffle after it flowed out from the holes in the baffle, and there was a large dead zone above the first outlet. Temperature distribution in the original tundish configuration was not uniform. The temperature difference between high temperature zone and low one on the liquid surface outside the pouring zone was 10.7℃ and the temperature difference among the outlets of the tundish 4℃. With the improved baffle, molten steel mainly flowed in the upper layer of tundish bath after it departed from the holes in the baffle. The flowing route of liquid steel became long and dead zone small in the tundish. Temperature field of liquid steel turned uniform and temperature of steel flowing out from the tundish outlets was the same.

Simulation of Slag Splashing in a 210 t Top-Bottom Combined Blowing Converter

LIAO Guang-fu CHEN Min LI Guang-qiang ZHANG Hao XIAO Zun-hu SU Feng-guang

. 2011, 11(1):  31-35. 

Asbtract ( )   PDF (378KB) ( )  

Related Articles | Metrics

Simulation experiments with water as slag on slag splashing in a 210 t top-bottom combined blowing converter were carried out. By measuring the amount of water taken as slag splashed onto the lining, the effects of operating parameters on slag splashing were examined, the optimal parameters were obtained as follows: top-blown gas flow rate was 50000 Nm3/h, lance height around 3680 mm, nozzle angle 15°, amount of slag remained for splashing 21 t, layout A1 of bottom tuyeres and bottom flow rate about 900 Nm3/h.

Water Model Study on a 210 t Top-Bottom Combined Blown Converter

CHEN Min LIAO Guang-fu LI Guang-qiang YUAN Gang XIAO Zun-hu SU Feng-guang

. 2011, 11(1):  36-39. 

Asbtract ( )   PDF (235KB) ( )  

Related Articles | Metrics

The impacts of bottom tuyeres layout, flowrate of top blowing, lance height and other factors on mixing time, penetrating depth and cavity diameter in a 210 t top-bottom combined blown converter were studied using water model. The effects of different factors on the mixing time, penetrating depth and cavity diameter were not consistent. The operating parameters of the shortest mixing time were obtained as follow: layout A3 of bottom tuyeres, flowrate of top blowing 50000 Nm3/h, flowrate of bottom blowing 1000 Nm3/h, lance height 1700 mm, and nozzle angle 17°.

Mathematical Modeling of Fluid Flow in an AOD Converter Bath under Conditions of Combined Side and Top Blowing: Application of the Model to Combined Side and Top Blowing Process and Results

WEI Ji-he HE Yuan SHI Guo-min

. 2011, 11(1):  40-43. 

Asbtract ( )   PDF (343KB) ( )  

Related Articles | Metrics

The fluid flows in the bath of a 120 t AOD converter and its water model with a 1/4 linear scale in the combined side and top blowing have been treated and analyzed from the superposition of the computed results of those during the simple side and top blowing processes respectively by the side and top blowing components of the mathematical model developed for the molten steel flow in an AOD bath under the conditions of combined blowing. The results demonstrate that the mathematical model can be used to simulate the fluid flow in an AOD bath with the combined blowing. The liquid flow in the bath with the combined blowing results from the gas side blowing streams under the influence of a gas top blowing jet, the gas side streams play a governing role for it, and the liquid is equally in vigorous stirring and circulatory motion during the combined blowing also without obvious dead zone in the whole bath. Compared with those in a simple side blowing, the impinging of a gas top blowing jet does not change the essential features of gas agitation and fluid flow in the bath, but can make the local flow pattern of the liquid vary evidently. The changes in the angle between each tuyere and the tuyere number have similarly not altered the basic characteristics and patterns of gas stirring and liquid flow and turbulent kinetic energy distribution in the bath. However, at a given tuyere number and gas side blowing rate or a given angular separation between each tuyere and gas side blowing rate, the variation of the number or the angle can change locally them. Using 6 tuyeres with 27° for blowing can reach more uniform flow field and turbulent energy distribution of the liquid in the AOD bath with the combined blowing than that taking 7 tuyeres with 18° or 22.5° and 6 tuyeres with 22.5°.

反应与分离

Removal of Fluoride from Aqueous Solution by Modified Al-Zr Pillared Bentonite

LONG Min TANG Yan-kui TONG Zhang-fa LIANG Da-wen

. 2011, 11(1):  44-49. 

Asbtract ( )   PDF (469KB) ( )  

Related Articles | Metrics

Microwave-aided synthesized Al-Zr pillared bentonite (MAZPB) was applied to remove fluoride from aqueous solution. MAZPB was characterized by SEM and XRD. The influences of pH value, adsorbent dose and presence of other anions on fluoride adsorption on MAZPB were investigated. The results showed that MAZPB efficiently adsorbed F- in a wide pH range (3.5~10), and its removal rate remained above 89%. The presence of other ions such as ferric ion and carbonate affected the adsorption of fluoride significantly, indicating the selective nature of the adsorbent. The kinetic parameters of the adsorption showed that the adsorption kinetics followed a pseudo-second-order model. The Freundlich model yielded a much better fitting than the Langmuir model, indicating that the physical adsorption was predominant. Used MAZPB could be regenerated by alum, and the removal rate of fluoride reached 81.93%.

Experimental Study on Rational Technology of Dephosphorization Pretreatment for High Phosphorus Content Hot Iron

ZHOU Dong-jin BI Xue-gong WU Jie HUANG Zhi-cheng WEN Zhi-jun XIONG Wei LI Yong-bo JIN Yan

. 2011, 11(1):  50-55. 

Asbtract ( )   PDF (238KB) ( )  

Related Articles | Metrics

The effects of oxygen supply method and flux consumption on temperature drop during the dephosphorization process and efficiency of high phosphorus hot iron with about 0.6%(w) phosphorus were studied in laboratory. The results revealed that by using pure solid form oxygen the slag volume was big, temperature drop great, and phosphorus oxidation rate was fast, the reaction was basically completed for 2 min with dephosphorization rate up to 89.45% while by partially replacing solid form oxygen with gaseous oxygen, slag volume was smaller, temperature drop less, but the treatment time was longer and the final dephosphorization efficiency was negatively affected. Dephosphorization rate was only 51.13% when gaseous oxygen content reached 75%. The rational dephosphorization pretreatment technology for high phosphorus hot iron should be close control of solid dephosphorization agent consumption, replacement of solid form oxygen with proper amount of gaseous oxygen at about 25% and control of shorter pretreatment time.

Recovery of Valuable Metals by Leaching of Roasted Jarosite Residue

XUE Pei-yi JU Shao-hua ZHANG Yi-fei WANG Xin-wen

. 2011, 11(1):  56-60. 

Asbtract ( )   PDF (267KB) ( )  

Related Articles | Metrics

A new process of roasting-ammonium chloride leaching-alkali leaching for recovery of valuable metals and iron in jarosite residue generated during zinc hydrometallurgy was studied by experiment. After roasting of jarosite at 650℃ for 1 h, the main phase of KFe3(SO4)2(OH)6 containing Pb and Zn was decomposed into Fe2O3, ZnSO4 and PbSO4. When the roasted jarosite residue was leached by 5 times with aqueous solution of 6 mol/L ammonium chloride at 105℃ for 2 h, over 95% of Zn, Pb and Cd in the jarosite was leached and the iron content was raised from 22% to 40%. The leached residue was further leached with 23.08%(w) NaOH solution at 160℃ for 1 h, Fe content in the final residue was 54%, which could be used as qualified iron concentrate.

Extraction Kinetics of Mn(II) by the Sodium Salt of P204

XING Peng WANG Chen-yan

. 2011, 11(1):  61-64. 

Asbtract ( )   PDF (190KB) ( )  

Related Articles | Metrics

The extraction kinetics of Mn(II) from sulfate medium by the sodium salt of P204 (Na-P204) was studied using a modified Lewis cell. The effects of stirring speed, temperature, interfacial area, and concentrations of Na-P204 and of Mn(II) on the extraction rate of Mn(II) were investigated. The extraction rate increased with increasing of stirring speed, temperature and interfacial area. The extraction rate remained constant with further increase of stirring speed when it was above 104 r/min. The apparent activation energy of Mn(II) extraction by Na-P204 was 23.50 kJ/mol. The rate determining step of Mn(II) extraction by Na-P204 was chemical reaction at the interface. The extraction rate was proportional to the concentrations of Mn(II) in the aqueous phase and Na-P204 in the organic phase. The effect of concentration of Mn(II) on the extraction rate is less pronounced than that of Na-P204. The extraction rate could be represented by the following equation under the conditions of 18℃ and interfacial area 21.19 cm2: r=2.06′10-2[NaA](O)1.35[Mn2+]0.41.

过程与工艺

Study on Smelting Reduction Ironmaking of Copper Slag

LI Lei HU Jian-hang WANG Hua

. 2011, 11(1):  65-71. 

Asbtract ( )   PDF (246KB) ( )  

Related Articles | Metrics

According to the mechanism of smelting reduction, the process of smelting reduction ironmaking from copper slag was studied. The effects of slag basicity, holding temperature, holding time and CaF2 addition (mass ratio of CaF2 to CaO) on the iron yield and sulfur, phosphorus removal efficiency from the molten iron were examined. XRD analysis results indicated that the iron phases in the copper residue were mainly 2FeO×SiO2 and Fe3O4. In N2 atmosphere, the iron yield of 89.28%, sulfur content in hot metal of 0.039%, and phosphorus content of 0.087% were obtained in the conditions of basicity 1.6, holding time 30 min at 1575℃ and CaF2/CaO 10%. The study worked out the problem of high sulfur content in the iron from smelting reduction.

Thermodynamic Analysis and Experimental Study on Alkali-roasting Treatment of Limonitic Laterite Ore with Sodium Carbonate

GUO Qiang QU Jing-kui HAN Bing-bing WEI Guang-ji QI Tao

. 2011, 11(1):  72-78. 

Asbtract ( )   PDF (320KB) ( )  

Related Articles | Metrics

Thermodynamic analysis and experimental study on the treatment of limonitic laterite ore by sodium carbonate roasting have been performed. Thermodynamic analysis results show that in the range of 500~1500 K, the decomposition of goethite and gibbsite can take place easily whereas chromite is decomposed spontaneously at high temperature. The formation reaction of sodium chromate during the alkali-roasting treatment process is feasible, and the thermodynamic trend FeO×Cr2O3>Cr2O3. Increasing the roasting temperature increases the leaching rate of Cr. And high temperature favors the production of sodium aluminate and sodium silicate, and increasing the roasting temperature improves the leaching rates of Al and Si in 1123~1273 K. However, with the further increase of temperature, the preferential generation of sodium alumino-silicate precipitates by the reaction between sodium aluminate and silicon dioxide can result in loss of soluble Al, Si, and Na. Experimental results show that the leaching rates of Cr, Al, and Si are 99.7%, 82.8%, and 40.4%, respectively, under the roasting temperature of 1273 K, roasting time of 2 h, and mass ratio of Na2CO3 t ore of 0.6.

Effect of Pulsed Electric Field on Solidification Process of Fe-C-P System Alloy

HONG Peng WANG Hai-chuan LI Xin LI Jie LIAO Zhi-you QIAN Zhang-xiu

. 2011, 11(1):  79-84. 

Asbtract ( )   PDF (614KB) ( )  

Related Articles | Metrics

Imposing of pulsed electric field can effectively reduce the grain boundary segregation and improve the solidification structure Fe-C-P alloy during solidification of its melt, but it can also cause the migration and redistribution of elements, in which element P migrates from the anode to the cathode, the migration law of element C is similar to P. As the voltage increases, the standard deviation of P segregation is decreased from 1.67 to 1.26, and that of C from 1.03 to 0.65. After processing, the inclusions are mainly distributed in the central region, but phosphorus-containing inclusions can not be observed, there is a small amount of MnS and Al2O3 inclusions.

Assessment of Oxygen Concentration Unit from Measured Oxygen Activity by Oxygen Sensor Based on Metallurgical Thermodynamics

YANG Xue-min SHI Cheng-bin ZHANG Meng LI Dao-ming

. 2011, 11(1):  85-90. 

Asbtract ( )   PDF (207KB) ( )  

Related Articles | Metrics

Taking Celox￠s oxygen sensor from Heraeus Electro-Nite Shanghai Company Limited as an example, the measured oxygen activity by the sensor has been compared with the reported oxygen activity from literatures, the calculated oxygen activity of aluminum-killed molten steel during a 210 t LF refining process based on [Al]-[O] equilibrium and the calculated oxygen activity of molten steel at steelmaking end-point in an 80 t top-bottom combined blown converter based on [C]-[O] equilibrium. The comparison results show that the measured oxygen activity from Celox oxygen sensor as a representative of commercial oxygen sensors is based on 1%(w) solution as standard state and one part per million, [10-6 O] as oxygen concentration unit, but not 1%(w), [%O] as oxygen concentration unit. Therefore, the magnitude of measured oxygen activity by the sensor must be treated as 10-4, rather than the displayed 10-6 in the display device of Celox oxygen sensor under the condition of applying 1%(w), [%O] as oxygen concentration unit.

Experimental Investigation on Direct Reduction of Iron Ore Powder by Pulverized Coal in a Circulating Fluidized Bed

FAN Li-juan; LU Qing-gang NA Yong-jie YU Kuang-shi;

. 2011, 11(1):  91-96. 

Asbtract ( )   PDF (599KB) ( )  

Related Articles | Metrics

The effect of reaction temperature on the reduction degree and microscopic structure of reduced products, and the reduction process of iron ore powder by Datong pulverized coal in nitrogen was examined in a circulating fluidized bed in the reaction temperature range from 800℃ to 950℃. The metallization and reduction degrees of reduced products increase as the reaction temperature increases. There is a larger increase at 800~850℃, moderate increase at 850~900℃ and the greater increase at 900~950℃. The metallization and reduction degrees can reach 63% and 87%, respectively, when the reaction temperature ascends to 950℃. Compared with the raw iron ore powder, the specific surface area and total pore volume of reduced products are increased at 800℃, while reduced at the other temperatures, the corresponding variation of the average pore size parameters is opposite.

Experimental Study on Assimilation of Iron Ores at Home and Abroad

ZHANG Jian-liang SU Bu-xin CHE Xiao-mei LIN Xiang-hai KONG De-en GUO Hong-wei

. 2011, 11(1):  97-102. 

Asbtract ( )   PDF (245KB) ( )  

Related Articles | Metrics

Assimilation of 7 kinds of iron ores from Australia, Brazil, India, South Africa and China was evaluated and analyzed. The results show that the ores with different types or from different places are apparently different in assimilation. Among them, the assimilation of India ore is the highest, of which the lowest assimilation temperature is 1235℃, the content of SiO2 9.52%, and content of crystallized water 5.67%; except these, the ore is hematite, showing as crumbly particles. The lowest assimilation ore is South Africa ore, of which the lowest assimilation temperature is 1355℃, the content of MgO up to 2.37%, and content of crystallized water 0.05%, except these, the ore is construction-compact magnetite. The assimilation of the ores has negative correlation with MgO content and binary basicity, while it has positive correlation with porosity and the content of SiO2, Al2O3, and crystallized water. The iron ores with small crystalline size and microstructure looseness have relatively higher assimilation.

Study on Technological Conditions in Preparation of Anhydrous Cerium Chloride

WU Jin-xiu LI Mei LIU Zhao-gang HU Yan-hong WANG Mi-tang

. 2011, 11(1):  103-106. 

Asbtract ( )   PDF (275KB) ( )  

Related Articles | Metrics

Technological conditions in preparation of high purity anhydrous cerium chloride with ammonium chloride as chlorinating agent to chlorinate cerium oxide in argon atmosphere were studied. The reaction temperature and time, and dosing ratio of reactants by orthogonal experiments for optimization of the preparation conditions were examined, and its product was characterized by XRD. The results showed that by chlorinating cerium oxide for 30 min with ammonium chloride dosage in a molar ratio of n(NH4Cl):n(CeCl4)= 12:1 at 300℃, the chlorinating rate of oxide reached 99.6%, the impurity in the anhydrous cerium chloride product was less than 5%.

生化工程专栏

Preparation of Hollow Silica Microspheres with Synechocystis sp. PCC 6803 as Bio-template

ZHANG Bo REN Tian-rui WU Qing-hai WANG Quan-xi FENG Hao

. 2011, 11(1):  107-112. 

Asbtract ( )   PDF (1020KB) ( )  

Related Articles | Metrics

Silica particles with different morphologies were prepared using cyanobacteria Synechocystis sp. PCC 6803 as a biotemplate via a sol-gel route. The Synechocystis sp. PCC 6803 and as-prepared silica were characterized. The reaction conditions of selective synthesis of monodisperse silica and hollow silica microspheres were established. The formation mechanism of different morphologies was discussed. The results indicated that the silica microspheres had an amorphous structure with an average diameter of 1.5 mm, and retained the original morphology of the cells. SiO2 nanoparticles could be uniformly coated on the surface of cells to form the hollow SiO2 microspheres, which had uniform wall thickness and could maintain the original morphology of cells. It was confirmed that the formation mechanisms of SiO2 hollow spheres and SiO2 microparticles were based on the difference between adsorption and penetration.

Production of Coenzyme Q10 in Fed-batch Fermentation by Agrobacterium tumefaciens

JIN Sai; XU Jian; ZHANG Liang; DING Chong-yang; SHI Gui-yang;

. 2011, 11(1):  113-116. 

Asbtract ( )   PDF (223KB) ( )  

Related Articles | Metrics

The production of coenzyme Q10 by Agrobacterium tumefaciens Q14 was studied under fed-batch fermentation by adding restrictive nutrient substances in a 15 L fermentor. The best process of fed-batch fermentation was obtained by stepwise optimization in order to maintain glucose concentration between 5 and 15 g/L and phosphorus concentration between 50 and 120 mmol/L. 5%(j) fresh medium was added at 30 and 50 h, respectively, to satisfy the growth of cells. The results showed that the fermentation period was 84 h, a highest biomass of 87.2 g/L, coenzyme Q10 production of 2166.2 mg/L and productivity 25.9 mg/(L×h) which increased 7.8 times compared with batch fermentation.

材料工程专栏

Preparation of Nano-TiO2/Attapuleite Composite and Its Photocatalytic Kinetics

LIU Liang LU Jun LI Yun LIU Jia-qin WU Yu-cheng

. 2011, 11(1):  117-123. 

Asbtract ( )   PDF (732KB) ( )  

Related Articles | Metrics

XRD, HRTEM, EDS and SEM were used to analyze the formation of nano-TiO2/attapulgite photocatalytic composite prepared by sol-gel method. XRD analysis showed that the composite was the mixture of anatase and rutile. HRTEM and SEM images showed that a uniform layer of TiO2 particles was loaded on the surface of attapulgite. The effects of calcination temperature, dosage of catalyst and adsorption properties on the photocatalytic properties of the composite were examined. The results showed that the grain size of TiO2 prepared at 600℃ was 16 nm and the phase content of anatase 87%. The composite had a stronger adsorption to methyl orange, and the adsorption equilibrium constant Ka=0.00896 L/mg. The kinetic equations of photocatalysis were in accord with Langmnir-Hinshelwood model, second-order kinetic equations could describe the degradation well and photocatalytic kinetic equation was lnCt+0.00896Ct=0.418-0.0197t.

Influence of Heat Treatment on Microstructures and Properties of Nanosized Zirconia Powder and Coating

YAO Xing-he; ZHU Yong-ping ZHANG Wei-gang

. 2011, 11(1):  124-130. 

Asbtract ( )   PDF (782KB) ( )  

Related Articles | Metrics

The effects of high-temperature sintering, plasma torch and plasma flow heat treatments on the properties of ZrO2-8%mol Y2O3 (8YSZ) spherical powder and plasma sprayed coating were investigated. The results show that the plasma sprayed coating derived from plasma torch treated powder of 8YSZ has the highest bonding strength of 25 MPa and the best thermal shock resistance of 41 thermal cycles which is under water cooling after treatment at 1200℃ for 5 min. The coating fabricated by plasma flow treated 8YSZ has very low bonding strength of 11 MPa and poor thermal shock resistance of 17 thermal cycles. The coating prepared by sintering treated 8YSZ relies on the temperature and time of treatment, and the best mechanical properties are obtained when 8YSZ powder is treated at 1200℃ for 2 h, the average is 21 MPa and 38 thermal cycles.

Crystallization Process of AlOOH Nano-particles with Different Shapes in Hydrothermal Systems

HAO Bao-hong FANG Ke-ming

. 2011, 11(1):  131-136. 

Asbtract ( )   PDF (1014KB) ( )  

Related Articles | Metrics

The model of growth unit was established for synthesis of AlOOH in hydrothermal systems, and the transfer process of growth unit deduced. The crystallization process of substances was analyzed from the angle of motion of growth units for the first time. The influential mechanisms of different hydrothermal environment systems on crystallization process and final morphology of heteromorphic AlOOH particles were discovered from the perspective of atomic aggregates. Emphasis was focused on the mechanisms of growth unit at various pH values in acidic medium, and characteristics of Al3+ tripolymers, ([Al3(OH)4(OH2)9]5+, [Al3(OH)5(OH2)8]4+ and [Al3(OH)6(OH2)7]3+) of nano-AlOOH. The formation process of the aggregates determined by various coordinate bonds of Al3+ tripolymers and the essence of oriented growth of AlOOH were discovered. The established model was directly proved with the experimental samples. Furthermore, the existence of polymers and motion of growth unit were proved right by means of detecting the infrared spectrogram. Various pH values determine different growth units, different growth units determines diverse successive transfer process, and finally determines one-dimensionally oriented growth of the crystal into different morphologies.

Preparation of Nano-Al2O3 Particles via H2/Air Flame Synthesis and Their Dispersion Performance

DING Hong-qiu; HU Yan-jie LI Chun-zhong

. 2011, 11(1):  137-142. 

Asbtract ( )   PDF (1020KB) ( )  

Related Articles | Metrics

Nano-Al2O3 particles were prepared via H2/air flame synthesis in a multi-jet reactor with anhydrous AlCl3 as precursor, the morphology, structure, crystallinity, size and specific surface area of the prepared nanoparticles were investigated, and the influences of flame configuration and maximum temperature in the reaction zone on their properties characterized. The results showed that the size of particles increased with the flame temperature increasing, and their morphology changed from irregular chain-like aggregates to well dispersed spherical nanoparticles. At the same time, a simple γ-phase was gradually transformed to δ and δ* phases. Dispersion of nano-Al2O3 particles had strong stability. The growth mechanism of particles and aggregates at rapid high-temperature reaction was discussed. The morphology and particle size of prepared nanoparticles depended on the competition among the key influential factors.

Study on Synthesis of TiO2 Powder Doped with Sm by Sol-Gel Method and Its Photoluminescent Properties

SONG Jin-ling ZHOU Chang-cai HOU Zhi-peng LI Xia CAI Ying ZHANG Yin

. 2011, 11(1):  143-147. 

Asbtract ( )   PDF (315KB) ( )  

Related Articles | Metrics

The influences of way and quantity of water adding, reaction temperature and inhibitor on the gelatification of sol are studied. The optimal conditions have been finally selected. The adding way of water is dripping, volume ratio of tetrabutyl titanate to water 5:1, reaction temperature 30~35℃ and inhibitor nitric acid. Under the optimized conditions, the TiO2 powder and TiO2 powders doped with different contents of Sm3+ are prepared by the sol-gel method, and their structures and luminescent properties characterized by XRD and photoluminescence spectra, respectively. The results indicate that the structure of prepared TiO2 powder is anatase, and doping ion Sm3+ can restrain the growth of TiO2 crystals. The doped Sm causes the changes of new emission peaks and their intensities under different Sm3+ doping quantities, achieving the minimum value of intensity at 4.0%(w). The morphologies of the TiO2 powder are particles with the diameters of 5~10 nm.

Catalytic Activity of Low-loading Pd and Pt Supported Catalysts for Combustion of Dimethyl Ether

WANG Yuan-yuan XU Hang FENG Dong-mei WANG Jin-fu

. 2011, 11(1):  148-152. 

Asbtract ( )   PDF (217KB) ( )  

Related Articles | Metrics

In order to select desirable catalysts for combustion of dimethyl ether (DME), a series of low-loading Pd and Pt catalysts were prepared by impregnation on g-Al2O3. The effects of loading amount and sequence of the metals on catalytic performance were investigated, and the effect of loading molar ratio of the metals. Using 0.025%(w) Pt-loaded catalyst, DME was completely converted to CO2 and H2O at 190℃. The catalyst with Pd and Pt loaded together [Pd:Pt=2:1(mol), Pt 0.025%(w), Pd 0.027%(w), Pt first-loaded] had better performance, by which DME was completely converted at 175℃. Catalytic activity of these two catalysts was decreased by less than 5% after 200 h reaction.

Synthesis of Biodiesel Catalyzed by SO3H-functionalized Quaternary Ammonium Ionic Liquids

ZUO Shuang LIN Jin-qing SUN Ya-fei FANG Guo-yang

. 2011, 11(1):  153-157. 

Asbtract ( )   PDF (308KB) ( )  

Related Articles | Metrics

4 kinds of SO3H-functionalized quaternary ammonium ionic liquid were prepared by two-step method. Their IR and NMR spectra showed that their structures were in accordance with their theoretical structure. Their decomposition temperatures shown by TG were higher than 200℃, so they were enough stable as the catalyst in synthesis of biodiesel. Biodiesel was synthesized with triolein and methanol catalyzed by the 4 kinds of ionic liquid prepared. Their catalytic activity was related to their anion structure, and [n-But3N(CH2)3SO3H][CH3SO3] showed the best catalytic activity. The effects of reaction time, molar ratio of methanol to triolein and catalyst amount on the yield of fatty aid methyl ester were investigated when [n-But3N(CH2)3SO3H][CH3SO3] was selected as the catalyst of transesterification reaction. Under the conditions of molar ratio of methanol to triolein at 12:1, mass fraction of ionic liquid 7%(w), reaction temperature 65℃ and reaction time 24 h, the yield of fatty aid methyl ester reached 89.65%, and the ionic liquid was stable during the reaction and could be reused.

Preparation and Characterization of Iron-Nickel Alloy Nanoparticles

YUAN Ming-liang TAO Jia-hua YU Liang SONG Cong QIU Guan-zhou

. 2011, 11(1):  158-161. 

Asbtract ( )   PDF (1696KB) ( )  

Related Articles | Metrics

In ethanol-water system, Fe-Ni alloy nanoparticles were prepared by reduction of the mixture solution of FeSO4 and NiSO4 in the presence of surfactant with liquid-phase reduction method. Their samples were characterized by XRD, SEM and VSM, respectively. The results indicate that single FeNi3 alloy phase could be obtained under the optimized conditions of solution composition of molar ratio of FeSO4/NiSO4 at 1:3, 4 g NaOH and 15 mL N2H4×2H2O at 150℃ for 2 h, the values of saturation magnetization and coercivity were 121.36 A×m2/g, and 1.42 A/m. Besides, the influences of synthesis conditions on the magnetic properties of Fe-Ni alloy nanoparticles were also examined.

综述

Research Progress in the Modeling Theory of Airlift Loop Reactor

ZHANG Li-ying HUANG Qing-shan

. 2011, 11(1):  162-173. 

Asbtract ( )   PDF (292KB) ( )  

Related Articles | Metrics

The hydrodynamic models for bubbly flow in airlift loop reactor are reviewed. In addition to the classification of two-fluid models according to the averaging methods, the estimation models of bubble-induced turbulence are also categorized. Furthermore, the inter-phase forces commonly used and some techniques of solving the bubbly flow are summarized and evaluated. It is pointed out that Favre averaging two-fluid model combined with the k-e model, in which the bubble induced turbulence is considered with the Sato model, is a useful tool for the design and scaling-up of airlift loop reactor at the present stage. Moreover, the problems and topics of interest in the future work are suggested on the basis of analysis of state-of-the-art theory of bubbly flow.

Recent Research Development in Resolution Kinetics of Racemic Menthol by Lipase

NIAN Bao-yi HUANG Zhi-hua LUO Ju-xiang NIU Yu

. 2011, 11(1):  174-180. 

Asbtract ( )   PDF (331KB) ( )  

Related Articles | Metrics

A condensed review of the potential offered by lipase for resolution of racemic menthols for the past 10 years is presented. Especially, recent applications of the lipase catalytic approach and industrialization of unit operation to the preparation of the most important flavor, l-menthol, are comprehensively covered by analyzing their processes of transesterification, hydrolysis reaction and influential factors. The potential industrial processes based on lipase-catalytic methods are discussed in the terms of their advantages over classical ones. The optimal pathway of resolution is achieved by analyzing resolving routes of menthol and alternative of acyl agent for transesterification of menthol. And a vista of the future investigations is opened up for new realms from macro-kinetics of menthol resolution for the industrial processes.