Experimental Crystallization of Synthetic V-bearing Steelmaking Slag with Al2O3 Doped

The phenomenon of crystallization was implemented in the synthetic V-bearing steelwork slag based on the composition of factory slag from the Masted Co., and the possibility of undercooling as a technique to precipitate V-concentration phase was demonstrated. The effect of 20wt% Al2O3 additive introduced into the slag on intensifing the precipitation was also investigated. X-ray diffraction analysis ( XRD ) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) were used to investigate the slag after heat treatment. It is demonstrated that gehleaite and grossite are the major crystalline phases. Whitlockite with a high content of V2O5 ( called V-concentration phase hereafter) nucleates homogeneously and hetergeneously and grows with decreasing undercooling. At 1548 K, the crystals of V-concentration phase grow up as the duration of time, with a medium grain size of 25μm at 300 rain holding time.     

Structure transition of nano-titania during calcination

1　INTRODUCTIONTitaniahasthreecrystallines :brookite ,anataseandrutile .Theirbasicstructuralunitisthesame[TiO6 ]octahedron ,buttheirlatticestructuresaredifferent .Forexample ,brookitebelongstorhombiccrystallo series ,whilerutileandanatasebelongtosquarecrystallo series .Thoughrutileandanatasearethesamecrystallo series ,theirsymmetricalelementsandunit cellparametersaredifferent[1] .Inrecentyears ,muchattentionhasbeenpaidtophasetransformationoftitaniaparticle ,especiallytothetemperatureofph…     

Regulation mechanism of EM parameters in natural ferrite and its application in microwave absorbing materials

1 Introduction Microwave absorbing materials (MAM) refer to a kind of materials that can be used to absorb the emitted electromagnetic (EM) energy and to minimize the wave reflected in the direction of an energy radar receiver. When the EM wave incidents into MAM, it is readily absorbed, attenuated, and changed into heat or other energy. MAM are functional materials that possess special performance for absorbing EM wave. Along with the advancement in radar and microwave technologies, MA…     

Microwave Synthesis of Cathode Material LixMn2O4 for Lithium-ion Battery

LixMn2O4 was synthesized rapidly by microwa heaing,the product phases of the microwave synthesis and comventional solid-solid-state synthesis were comparatively inesitigated,The capacity of microwave synthesis product decreases relatively slow,The lithium ion can be inserted into and extracted from the spinel framework structure fluently after cycling .But the capacity of the conventional solid-state synthesis product is more remarkably lowered.The spinel framework structure was destroyed which hindered the lithium ion from inserting and extracting,Tehe influential factors of the process parameters are discussed such as heat preservation time,pre-heating at 400℃ for 24 h and coupled agent.     

Synthesis, characterization and bioactivity evaluation of diallyl disulfide

1 INTRODUCTIONGarlic , one of the most frequently usedspices , has been known for its diverse biologicalactivities ,such as antithrombosis , antiatheroscle-rosis ,anti mutagenesis ,and antibacterial[1 2].It isrecently knownthat diallyl disulfide ,a major orga-no-sulfur compoundin garlicinhibits the growth ofhuman tumor cells from colon, lung, skin, andbreast origins[3 6].Smoll et al[7]reportedthat iodo-niumand allyl mercaptan could form diallyl disul-fide . Moreover , Challenger et al[8]r…     

Microwave absorbing characteristics and temperature increasing behavior of basic cobalt carbonate in microwave field

The microwave absorbing characteristics of basic cobalt carbonate, cobalt oxide (Co₃O₄), and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation, their temperature increasing curves were measured, and their ability to absorb microwave energy was also assessed based on the temperature increasing behavior of the material exposed to microwave field. Analyses of spectrum attenuation and relative frequency shift show that basic cobalt carbonate has weak capability to absorb microwave energy, while cobalt oxide has very strong capability to absorb microwave energy. It is feasible to thermally decompose basic cobalt carbonate though addition of small amount of cobalt oxide in microwave fields. The capability to absorb microwave energy of sample increases with an increase in mixing ratio of Co₃O₄.     

Solvothermal preparation and characteristics of Sn-doped In2O3

Sn-doped In2O3 （ITO） nanopowders were prepared in ethanol solvent by solvothermal process. The effects of the solvothermal temperature, coprecipitation pH value and SnO2 content on the products phase and microwave absorption were investigated by X-ray diffractometry and microwave reflectance. ITO nanopowders with cubic structure can be respectively prepared at 250 and 270 ℃ for 6 h. The prepared product is InOOH or the mixture of InOOH and In3Sn4O12 when the solvothermal temperature is below 250℃. With rising solvothermal temperature and prolonging time, the absorption of the ITO powders gradually decreases. The products are ITO nanopowders by coprecipitating at pH=9 or 11, but ITO powders with Sn3O4 at pH=6. The absorption of powders prepared at pH=6 is better than that at any other pH value. The products are all ITO nanopowders and crystal size reduces with increasing SnO2 content. The microwave absorption of ITO nanopowders with SnO2 content of 8% （mass fraction） is the best among samples with different SnO2 contents.     

Densification and sintering dynamics of 10NiO-NiFe2O4 composites doped with CaO

The effects of CaO content in the range from 0 to 4.0%, and sintering temperature on the phase composition, relative density and electrical conductivity of 10NiO-NiFe2O4 composites doped with CaO were studied. The results show that there is no change of structure for NiO or NiFe2O4; there is apparent oxygen absorbing and releasing behavior during the heating process in air for 10NiO-NiFe2O4 composites. Introduction of CaO can accelerate the densification of 10NiO-NiFe2O4 composites. The maximum value of relative density is 98.75% for composite doped with 2.0% CaO and sintered at 1 200 ℃, which is beyond about 20% for the undoped composites. The sintering activated energy of sample containing 2% CaO decreases by 15.87 kJ/mol, compared with that of the undoped sample.     

Dielectric tunable properties of BaTi<Subscript>4</Subscript>O<Subscript>9</Subscript>-doped Ba<Subscript>0.6</Subscript>Sr<Subscript>0.4</Subscript>TiO<Subscript>3</Subscript> microwave composite ceramics

BaTi₄O₉-doped Ba_0.6Sr_0.4TiO₃ (BST) composite ceramics were prepared by the conventional solid-state reaction and their structure, dielectric nonlinear characteristics and microwave dielectric properties were investigated. The secondary phase of the orthorhombic structure Ba₄Ti₁₃O₃₀ is formed among BST composite ceramics with the increase of BaTi₄O₉. At the same time, a duplex or bimodal grains size distribution shows fine grains in a coarse grain matrix. The degree of frequency dispersion of dielectric permittivity below T _m is increased initially and then decreased with respect to BaTi₄O₉. As the BaTi₄O₉ content increases, the tunability of composite ceramics decreases, while the Q value increases. Interestingly, 70 wt% BaTi₄O₉-doped BST has a tunability ∼4.0% (under 30 kV/cm biasing) versus a permittivity ∼68 and quality factor ∼134.1 (at ∼3.2 GHz). Supported by the Ministry of Science and Technology of China through 973-project (Grant No. 2009CB623302), the Cultivation Fund of the Key Scientific and Technical Innovation Project, Ministry of Education of China (Grant No.707024), Shanghai Committee of Science and Technology (Grant No. 07DZ22302), and Shanghai Foundation Project under 06JC14070     

金红石型TiO2/锐钛矿型TiO2/SiO2三元复合薄膜的合成

采用水热法,以钛酸正丁醑为初始原料,在FTO基底上沉积了金红石型TiO2纳米棒阵列,然后利用锐钛矿型TiO2纳米粒子及无定形SiO2对纳米棒进行了表面修饰,获得金红石型TiO2/锐钛矿型TiO2/SiO2三元复合薄膜.扫描电镜及X射线衍射分析结果表明,在FTO表面上沉积的TiO2为金红石型单晶纳米棒,其尺寸随反应时间的增加而增大.电化学测试结果表明,随着纳米棒尺寸的增大,相应复合薄膜的电化学反应电荷转移阻力增大.2种TiO2晶型混合引起的电子-空穴分离效应及混合的均匀程度直接影响到复合薄膜的光催化活性.水热反应7h得到的纳米棒阵列相应的复合薄膜显示了较好的电化学性能及光催化活性.     

Preparation and photocatalytic application of high temperature stabilized ZrSiO4@TiO2 hybrid nanostructure

A new ZrSiO4@TiO2 hybrid nanostructure was prepared by a heterogeneous flocculation method. Phytic acid was introduced to modify the surface charging of the components for hybrid assembly. The obtained powder was coated on ceramic tiles and fired at 900 ℃ to fabricate photocatalytic ceramic. Experimental results show that anatase TiO2 in the composite powder has high thermal stability until 1 200 ℃. ZrSiO4 matrix prevents the mass transfer of anatase TiO2 at high temperature and greatly retards the phase transition of anatase to rutile. Besides, the photocatalytic ceramic shows apparent activities for the degradation of methyl orange under ultra-violet irradiation.     

Microstructures and properties of WC-2OCo-1Y2O3 cemented carbide by hot-press and liquid phase sintering

Ultrafine tungsten carbide and fine cobalt as well as nano yttrium oxide powders were used as the raw materials. The effects of hot-press below the eutectic temperature and conventional liquid phase sintering on the structures and properties of WC-20Co-1Y2O3 cemented carbide were studied. It is shown that hot-pressed alloy has the character of isotropic properties and microstructure with homogeneous and ultrafine WC grains. However, the ultrafine and fully-densified structure is developed at the cost of the presence of large amount of cobalt-lake (uneven-ly distributed binder phase), and thus lower strength. Yttrium oxide in the alloy cannot play the role of grain growth inhibitor fully when cemented carbide with high content of cobalt and ultrafine raw materials is sintered at high liquid phase sintering temperature. Peculiar platelet-enhanced bi-model structure is formed in WC-20Co-1Y2 O3 cemented carbide by conventional liquid phase sintering, which points out that yttrium oxide in the alloy facilitates the formation of plate-like WC grain.     

Determination of trace multi-elements in coal fly ash by inductively coupled plasma mass spectrometry

The contents of Cr, Cu, Ni, As, Cd and Pb in coal fly ash were determined by a high resolution inductively coupled plasma mass spectrometry method. The sample digestions were performed in closed microwave vessels with HNO3, HClO4 and HF. The optimum conditions for the determination were obtained. The applicability of the proposed method was validated by the analysis of coal fly ash reference material (NIST SRM 1633a). The results show that most of the spectral interferences can be avoided by measuring in the high resolution mode (maximum mass resolution R=9 000). The detection limit is from 0.05 to 0.21 μg/g, and the precision is fine with relative standard deviation less than 4.3%.     

Photocatalytic activity of lanthanum and sulfur co-doped TiO<Subscript>2</Subscript> photocatalyst under visible light

A novel lanthanum and sulfur co-doped TiO2 photocatalyst was synthesized by precipitation- dipping method, and characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM） and UV-Vis diffuse reflectance spectroscopy. Compared with the S-doped TiO, La-doped TiO2 and the standard Degussa P25 photocatalysts, the lanthanum and sulfur co-doped TiO2 photocatalyst （the molar percentage of La is 3.0%） calcined at 450 ℃ for 2 h showed the strongest absorption for visible light and highest activities for degradation of reactive blue 19 dye in aqueous solution under visible light（λ〉400 nm） irradiation. It was also discovered that the co-doping of lanthanum and sulfur hindered the aggregation and growth of TiO2 particles, and the doping of lanthanum reduced slightly the phase transition temperature ofTiO2 from anatase to rutile.     

Nanocomposite films of V<Subscript>2</Subscript>O<Subscript>5</Subscript>−MoO<Subscript>3</Subscript> xerogel with poly ethylene oxide intercalation

Poly ethylene oxide (PEO)_x−V₂O₅−V₂O₅−MoO₃ (x=0, 0.5, 1) films were prepared by the sol-gel method. The synthesis and structure of the films were investigated by XRD, TG-DTA, FTIR, etc. The results show that V₂O₅−MoO₃ xerogel has a layered structure and its interlayer space increased from 1.3181 nm at x=0 to 1. 7898 nm at x=1 after the nanocomposite films were dried, and PEO in the interlayer changes the interface structure by forming hydrogen bonds with V=0 bands. CV measurement indicates that the intercalation of PEO improves insertion/extration properties of Li⁺ ions in the interlayer. ZHENG Jin-xia: Born in 1976 Funded by the National Natural Science Foundation of China (No. 50172036) and Natural Science Foundation of Hubei Province(No. 2001ABB083)     

Thermodynamics calculation on the oxidation and sulfur removal abilities of slag in EAF dust pellet reduction process

ＥＡＦｄｕｓｔｈａｓｂｅｅｎｃｌａｓｓｉｆｉｅｄａｓｈａｚａｒｄｏｕｓｗａｓｔｅ ,ａｎｄｉｔｉｓｈａｒｍｆｕｌｉｎｔｈｅｃｏｎｖｅｎｔｉｏｎａｌｌａｎｄ ｆａｌｌｄｕｅｔｏｃｏｎｔａｉｎｉｎｇｈｅａｖｙｍｅｔａｌｓ[1] .Ｍｏｓｔｒｅｃｙ ｃｌｉｎｇｍｅｔｈｏｄｓ[2 8] ｄｅｖｅｌｏｐｅｄｆｏｒｔｈｅｄｕｓｔｓａｒｅｏｎｌｙｆｏｒｔｈｅｒｅｃｏｖｅｒｙｏｆｌｅａｄ ,ｚｉｎｃａｎｄｃａｄｍｉｕｍ .ＴｈｅＥＡＦｄｕｓｔｆｒｏｍｓｔａｉｎｌｅｓｓｓｔｅｅｌｍａｋｉｎｇｍａｉｎｌｙｃｏｎ ｔａｉｎｓｎｉｃｋｅ…     

Thermodynamic calculation on the smelting slag of direct recycling of electric arc furnace stainless steelmaking dust

1　ＩＮＴＲＯＤＵＣＴＩＯＮＥｌｅｃｔｒｉｃａｒｃｆｕｒｎａｃｅ (ＥＡＦ)ｄｕｓｔｈａｓｂｅｅｎｃｌａｓｓｉｆｉｅｄａｓａｈａｚａｒｄｏｕｓｗａｓｔｅｄｕｅｔｏｉｔｓｈｉｇｈｃｏｎｔｅｎｔｏｆｓｏｍｅｈｅａｖｙｍｅｔａｌｓｌｅａｃｈａｂｉｌｉｔｉｅｓｓｕｃｈａｓｚｉｎｃ ,ｌｅａｄ ,ｃａｄｍｉｕｍａｎｄｃｈｒｏｍｉｕｍ ,ｓｏｉｔｈａｓｂｅｅｎｂａｎｎｅｄｆｒｏｍｌａｎｄｆｉｌｌｓｉｎｍａｎｙｃｏｕｎ ｔｒｉｅｓ .Ａｎｅｓｔｉｍａｔｅｄ 1 % 2 %ｍａｓｓｆｒａｃｔｉｏｎｏｆｔｈｅｓｃｒａｐｃｈａｒｇｅｄ…     

Carburization of ferrochromium metals in chromium ore fines containing coal during voluminal reduction by microwave heating

Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O):n(C) (molar ratio) as 1.00:0.84 and n(SiO₂):n(CaO) as 1.00:0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0–10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio. Foundation item: Project(50474083) supported by the National Natural Science Foundation of China; Project supported by the Baoshan Iron & Steel Co. Ltd. of China     

Effect of Rare Earth Oxides on the Microstructure and Microwave Dielectric Properties of CaO-MgO-Nb2Os-TiO2 System Ceramics

La2O3 and SrO-doped CaO-MgO-Nb2O3-TiO2 system ceramics were prepared by solid-state ceramic technique.The microstructure and microwave dielectric properties of CaO-MgO-Nb2O5-TiO2-La2O3 cermics can be adjusted by varying the amount of La^3＋ or Sr^2＋ ions respectively.The replacement of Ca^2＋ by La^3＋ at A-site of the ceramics increases the quality factor Q value（ at 7.6GHz）as well as the temperature coefficient of resonant frequency τf and decreases the dielectric constant εr and the substitution of Sr^2＋ at A-site in this ceramics system exhibits opposite characteristics.The microwave properties of La^3＋,Sr^2＋-doped CaO-MgO-Nb2O5-TiO2 system ceramics depend on the degree of octahedral distortion inside materials.     

Preparation of V-doped TiO2 photocatalysts by the solution combustion method and their visible light photocatalysis activities

A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO2 crystal lattice mainly in the form of V5＋ and causes a phase transition from anatase to mille. V doping can widen the light absorption range of TiO2, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO2 powders were evaluated by the photocatalytic degradation of methyl orange （MO） under visible light irradiation. It is found that V doping enhances the photoeatalyilc activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO2.