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Effects of Fe2O3 on the properties of ceramics from steel slag

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International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 413-419页

作者： Yu li li-hua zhao Ya-kun Wang Da-qiang Cang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China China Electronics Standardization Institute Number 1 An-Dingmeng East Road Beijing 100007 China

Ferric oxide is one of the key factors affecting both the microstructure and the properties of CaO-MgO-SiO2-based ceramics. Research on this effect is significant in the utilization of iron-rich solid wastes in ceramics. Ceramic samples with various Fe2O3 contents（0 wt%, 5 wt%, and 10 wt%） were prepared and the corresponding physical properties and microstructure were studied. The results indicated that Fe2O3 not only played a fluxing role, but also promoted the formation of crystals. Ceramics with 5 wt% of Fe2O3 addition attained the best mechanical properties with a flexural strength of 132.9 MPa. Iron ions were dissolved into diopside, consequently causing phase transformation from diopside and protoenstatite to augite, thereby contributing to the enhancement of its properties. An excess amount of Fe2O3 addition（10 wt% or more） resulted in deteriorated properties due to the generation of an excess volume of liquid and the formation of high-porosity structures within ceramics.

关键词： solid wastes ceramics ferric oxide fluxing role augite phase transformation

Control of the precipitation of TiN inclusions in gear steels

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International Journal of Minerals,Metallurgy and Materials 2014年第3期21卷 234-239页

作者： Wen-jun Ma Yan-ping Bao li-hua zhao Min Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

In the 20CrMnTi steel production process, the nitrogen content increased by 19 × 10^-6 and 29 × 10^-6, respectively, during ladle furnace（LF） refining and during the casting process from ladle to tundish. The protective casting is the key to decrease the N content. The results of thermodynamic calculations and a growth kinetics investigation show that TiN formation occurs only when the solidification fraction is greater than 0.533 under the controlled conditions used in this study for the manufacture of 20CrMnTi steel; the radius of TiN particles decreases as the Ti and N contents decrease and as the cooling rate increases. Furthermore, the theory of austenite grains controlled by second-phase particles was analyzed. The elemental analysis results showed that the Ti content was controlled at 0.04wt%–0.06wt% and the N content decreased to 0.005wt%, which satisfy the requirements for grain refinement but can also effectively prevent the precipitation of TiN inclusions in 20CrMnTi steel.

关键词： gear steels titanium nitride inclusions precipitation

Purification and characterization of a novel antifungal protein from Bacillus subtilis strain B29

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第4期10卷 264-272页

作者： Jing li Qian YANG li-hua zhao Shu-mei ZHANG Yu-xia WANG Xiao-yu zhao Department of life Science and Engineering Harbin Institute of Technology Harbin 150001 China Institute of Microbiology of Heilongjiang Academy of Sciences Harbin 150010 China Heilongjiang University Press Harbin 150040 China

An antifungal protein was isolated from a culture of Bacillus subtilis strain B29. The isolation procedure comprised ion exchange chromatography on diethylaminoethyl （DEAE）-52 cellulose and gel filtration chromatography on Bio-Gel P-100. The protein was absorbed on DEAE-cellulose and Bio-Gel P-100. The purified antifungal fraction was designated as B29I, with a molecular mass of 42.3 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）, pl value 5.69 by isoelectric focusing （IEF）-PAGE, and 97.81% purity by high performance liquid chromatography （HPLC）. B291 exhibited inhibitory activity on mycelial growth in Fusarium oxysporum, Rhizoctonia solani, Fusarium moniliforme, and Sclerotinia sclerotiorum. The 50% inhibitory concentrations （IC50） of its antifungal activity toward Fusarium oxysporum and Rhizoctonia solani were 45 and 112 μmol/L, respectively. B29I also demonstrated an inhibitory effect on conidial spore germination of Fusariurn oxysporum and suppression of germ-tube elongation, and induced distortion, tumescence, and rupture of a portion of the germinated spores.

关键词： Bacillus subtilis Antifungal protein Purification

Optical Properties of Plasmon Resonances with Ag/SiO2/Ag Multi-Layer Composite Nanoparticles

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Chinese Physics Letters 2010年第6期27卷 107-109页

作者： MA Ye-Wan ZHANG li-hua WU zhao-Wang ZHANG Jie School of Physics and Electric Engineering Anqing Teachers College Anqing 246011

Optical properties of plasmon resonance with Ag/SiO2/Ag multi-layer nanoparticles are studied by numerical simulation based on Green＇s function theory. The results show that compared with single-layer Ag nanoparticles, the multi-layer nanoparticles exhibit several distinctive optical properties, e.g. with increasing the numbers of the multi-layer nanoparticles, the scattering efficiency red shiRs, and the intensity of scattering enhances accordingly. It is interesting to find out that slicing an Ag-layer into multi-layers leads to stronger scattering intensity and more ＂hot spots＂ or regions of stronger field enhancement. This property of plasmon resonance of surface Raman scattering has greatly broadened the application scope of Raman spectroscopy. The study of metal surface plasmon resonance characteristics is critical to the further understanding of surface enhanced Raman scattering as well as its applications.

关键词：复合纳米粒子等离子体共振光学性能表面增强拉曼散射银纳米粒子格林函数理论散射强度共振拉曼散射

Oxidation-extraction desulfurization of model oil over Zr-ZSM-5/SBA-15 and kinetic study

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Frontiers of Chemical Science and Engineering 2014年第2期8卷 203-211页

作者： Chuanzhu LU Hui FU Huipeng li hua zhao Tianfeng CAI School of Petrochemical Engineering Liaoning Shihua University Fushun 113001 China

ZSM-5/SBA-15 composite molecular sieves were synthesized using post-synthesis method and characterized by X-ray diffraction and N2 adsorption-desorption. The oxidative-extration desulfurization of model oil was investigated by using hydrogen peroxide as the oxidant, tetrabutyl ammonium bromide as phase transfer catalyst, dimethyl sulfoxide as extractant, and Zr-ZSM-5/ SBA-15, Ag-ZSM-5/SBA-15, Ce-ZSM-5/SBA-15 as catalyst. Under the optimal conditions, the desulfurization rate decreases in the order： Zr-ZSM-5/SBA-15 〉 Ce-ZSM- 5/SBA-15 〉 Ag-ZSM-5/SBA-15. The highest desulfuriza- tion rate is 84.53% under the catalysis of Zr-ZSM-5/SBA- 15. Kinetics analysis shows that the reaction is pseudofirst-order with the activation energy of 44.23 kJ/mol.

关键词： composite molecular sieve oxidation desul-furation extraction kinetic

Coordinated control of carbon and oxygen for ultra-low-carbon interstitial-free steel in a smelting process

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International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1252-1259页

作者： Min Wang Yan-ping Bao Quan Yang li-hua zhao Lu lin State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing National Engineering Research Center of Flat Rolling Equipment University of Science and Technology Beijing

Low residual-free-oxygen before fmal de-oxidation was beneficial to improving the cleanness of ultra-low-carbon steel. For ultra-low-carbon steel production, the coordinated control of carbon and oxygen is a precondition for achieving low residual oxygen during the Ruhrstahl Heraeus （RH） decarburization process. In this work, we studied the coordinated control of carbon and oxygen for ultra-low-carbon steel during the basic oxygen furnace （BOF） endpoint and RH process using data statistics, multiple linear regressions, and thermodynamics computations. The results showed that the aluminum yield decreased linearly with increasing residual oxygen in liquid steel. When the mass ratio of free oxygen and carbon （[O]/[C]） in liquid steel before RH decarburization was maintained between 1.5 and 2.0 and the carbon range was from 0.030wt% to 0.040wt%, the residual oxygen after RH natural decarburization was low and easily controlled. To satisfy the requirement for RH decarburization, the carbon and free oxygen at the BOF endpoint should be controlled to be between 297 × 10^6 and 400 × 10^-6 and between 574 × 10^-6 and 775 × 10^-6, respectively, with a temperature of 1695 to 1715℃ and a furnace campaign of 1000 to 5000 heats.

关键词： low carbon steel smelting decarburization cleanness

Synthesis of steel slag ceramics: chemical composition and crystalline phases of raw materials

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International Journal of Minerals,Metallurgy and Materials 2015年第3期22卷 325-333页

作者： li-hua zhao Wei Wei Hao Bai Xu Zhang Da-qiang Cang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Two types of porcelain tiles with steel slag as the main raw material （steel slag ceramics） were synthesized based on the CaO-A1203-SiO2 and CaO--MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite, a-quartz, magnetite, and pyroxene crystals （augite and diopside） in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction （XRD） and electron probe X-ray microanalysis （EPMA） results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag.

关键词： ceramic materials synthesis steel slag chemical composition crystalline phases solid waste recycling

Model prediction of the effect of in-mold electromagnetic stirring on negative segregation under bloom surface

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International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 319-327页

作者： Yu-kun Huo li-hua zhao Hang-hang An Min Wang Chang-dong Zou State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China National Engineering Research Center of Flat Rolling Equipment University of Science and Technology BeijingBeijing 100083China Institute of Research of Iron and Steel(IRIS)of Shasteel of Jiangsu Province Zhangjiagang 215625China

Aiming at the problem of negative segregation under a bloom surface, a coupling macrosegregation model considering electromagnetic field, flow, heat, and solute transport was established based on the volume average method to study the effect of in-mold electromagnetic stirring(M-EMS) on the negative segregation under the bloom surface. In the model, the influence of dendrite structure on the flow and solute transport was described by the change of permeability. The model was validated by the magnetic induction intensity of M-EMS and carbon segregation experiment. The results show that the solute C in the solidified shell in the turbulent zone of the bloom undergoes two negative segregations, whereby the first is caused by nozzle jet, and the second by the M-EMS. The severities of the negative segregation caused by M-EMS at different currents and frequencies are also different, and the larger the current is, or the smaller the frequency is, the more serious will be the negative *** the M-EMS, the solute C distribution in the liquid phase of the bloom is more uniform, but the mass fraction of C in the liquid phase is higher than that without M-EMS.

关键词： continuous casting in-mold electromagnetic stirring bloom negative segregation numerical simulation

High-temperature mechanical properties and deformation behavior of high Nb containing TiAl alloys fabricated by spark plasma sintering

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 354-359页

作者： Xin Lu li-hua zhao Lang-ping Zhu Bin Zhang Xuan-hui Qu State Key Laboratory for Advanced Metals end Materials School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Beijing Institute of Aeronautical Materials Beijing 100095 China

A high Nb containing TiA1 alloy was prepared from the pre-alloyed powder of Ti-45Al-8.5Nb-0.2B-0.2W-0.02Y （at%） by spark plasma sintering （SPS）. Its high-temperature mechanical properties and compressive deformation behavior were investigated in a temperature range of 700 to 1050℃ and a strain rate range of 0.002 to 0.2 s 1. The results show that the high-temperature mechanical properties of the high Nb containing TiA1 alloy are sensitive to deformation temperature and strain rate, and the sensitivity to strain rate tends to rise with the deformation temperature increasing. The hot workability of the alloy is good at temperatures higher than 900℃, while fracture occurs at lower temperatures. The flow curves of the samples compressed at or above 900℃ exhibit obvious flow softening after the peak stress. Un- der the deformation condition of 900-1050℃ and 0.002-0.2 s 1, the interrelations of peak flow stress, strain rate, and deformation tempera- ture follow the Arrhenius＇ equation modified by a hyperbolic sine function with a stress exponent of 5.99 and an apparent activation energy of 441.2 ***-1.

关键词： titanium-aluminum alloys spark plasma sintering (SPS) mechanical properties deformation activation energy