3t电渣钢9Cr2Mo工艺实践

为进一步提高冷轧辊电渣锭的内(外)质量、降低生产成本的要求,贵阳特钢采用400mm×300mm矩形连铸坯取代(φ)330mm铸锭做为电渣母材,在计算机全过程自动控制下,实现1支自耗电极重熔1支3吨电渣锭9Cr2Mo.电渣冶炼的填充比由初期的0.347提高到0.487,电渣锭成锭率由91.17%提高到96.87%,电渣重熔电耗由1762kWh/t下将到1477 kWh/t.     

电渣重熔渣系对GCr15轴承钢洁净度的影响

针对目前在电渣重熔(ESR)GCr15轴承钢D类夹杂物超标问题,设计不同渣系,并分别借助Factsage软件和经验公式计算了渣系的熔化特性、黏度、电导率等物性参数,采用实验室渣金平衡实验及现场2.5 t电渣重熔实验分析得出：最优ESR渣系为55CaF₂-25Al₂O₃-15CaO-5MgO。使用新渣系平均全氧含量较传统渣系降低41.98%,并且能够降低电渣锭不同位置的全氧含量;对于1～5μm夹杂物个数较原始渣系下降了31.25%。通过渣系对夹杂物调控,改善了GCr15轴承钢中D类夹杂物,评级级别可达到0.5级,能够更好地“净化”电渣锭。     

电渣炉渣参数的优化选择

本文论述了电渣冶炼渣参数优化选择的理论与实践。大生产应用表明,在保证电渣钢质的同时,渣量可减少45％,电耗降低19.4％,具有较显著的经济效益。     

The effect of the framework structure on the chemical properties of the vanadium oxide species incorporated within zeolites

V-silicalite catalysts (VS-1 and VS-2) prepared by hydrothermal synthesis have been studied by ESR, XAFS (XANES and EXAFS) and photoluminescence spectroscopy. The in situ characterization of these V-silicalites shows that vanadium is present within the zeolitic framework as a highly dispersed tetrahedrally coordinated V-oxides, VO₄ unit, having a short V=O bond length. Photoluminescence spectroscopy in static and dynamic mode, as well as XAFS studies allow to detect in the V-silicalites different V species than that present in V-HMS or V/SiO₂, in terms of V=O bond length, vibrational energy, bond angle and lifetime of the excited triplet state. It is suggested that the combined contribution of the neighboring Si---OH group attached to the VO₄ unit and the zeolitic rigid framework structure of V-silicalites cause a more significant and pronounced effect on the chemical properties of the VO₄ unit than the flexible structure of V-HMS or V/SiO₂. Moreover, the dynamic quenching of the phosphorescence by the addition of reactant molecules such as NO or propane indicates that the V species in the excited triplet state can be expected to be the active sites for the photocatalytic reactions.     

雅砻江楞古水电站场址区宋玉断层活动性研究

楞古水电站位于区域构造复杂的雅砻江中游, 场址周边断裂构造较发育, 场址区内发育有较大的宋玉断层, 研 究其活动性对枢纽建筑布置和工程抗震设防措施均具有重要意义。在遥感解译的基础上, 通过野外验证和追踪调 查, 结合断层构造岩石英形貌扫描、 电子自旋共振(ESR) 测龄和近代地震震中分析, 确定了宋玉断裂的活动年代, 得 出了宋玉断层不属于工程活动断层的结论。     

In situ ESR of CrH-ZSM-5 up to 500°C in flowing gas containing O2, H2O,CCl4, NO,NO2, and C3H6

A flow cell was used for the in situ ESR monitoring of the state and reactivity of chromium ions in Cr-ZSM-5. Calcination of Cr(NO₃)₃/NH₄-ZSM-5 in air at 500°C is accompanied by migration of chromium ions inside the zeolitic channels and stabilization ofisolated Cr⁵⁺ cations near lattice A1³⁺ ions. Calcination of Cr-ZSM-5 at 750°C leads to a gradual disappearance of the isolated Cr⁵⁺ cations and formation of -Cr₂O₃ microcrystals. All the Cr⁵⁺ cations are accessible to gas-phase molecules: O₂ strongly broadens the dipole-dipole signal; H₂O sorption increases the local crystal field symmetry; admission of CCl₄ results in a small change of the Cr⁵⁺ local coordination; strongly stabilized complexes on Cr-ZSM-5 are observed upon sorption of either NO or NO₂. The sorption of C₂H₆ on Cr-ZSM-5 at 20°C is accompanied by a gradual reduction of the Cr⁵⁺ sites. At 500°C in [C₃H₆ + O₂ + He] flow, even at a large excess of oxidant, the reduction of a noticeable part of Cr⁵⁺ ions takes place. At 400°C, in the same gas mixtures, a deeper reduction of Cr⁵⁺ occurs. Closer to stoichiometric conditions, in a [C₃H₆ + NO + He] flow with 120% excess of oxidant the Cr⁵⁺ is completely reduced at 500°C. The oxidation of propene is accompanied by coke deposition on the surface of the catalyst. The implications of the results are discussed.     

TiO2／UV／O2和TiO2／UV／N2体系降解水中对氯硝基苯

以商用TiO2P25为催化剂,分别在TiO2/UV/O2和TiO2/UV/N2两种体系下进行降解对氯硝基苯(pCNB)试验.采用ESR对两种体系下光催化反应形成的.OH进行测定,利用LC-MS对两种体系下反应形成的中间产物进行了定性和定量分析,最后对pCNB降解过程中氯和硝基的存在形式进行了研究.结果表明:TiO2/UV/O2体系的催化降解效果要明显优于TiO2/UV/N2体系;两种反应体系都有.OH产生,并且TiO2/UV/O2体系产生的.OH的量多于TiO2/UV/N2体系产生的.OH的量;TiO2/UV/O2体系形成的中间产物的种类要多于TiO2/UV/N2体系形成的,苯环上的氢、氯、硝基均可被.OH取代形成对硝基酚(pNP)、5-氯-2-硝基酚(5-C-2-PN)等酚类物质;两种体系下均有Cl-和NO2-存在,其中Cl-生成势与pCNB的去除势一致,只有TiO2/UV/O2体系中存在NO3-.     

Motional heterogeneity of polystyrene-block-polybutadiene: a spin probe study

Polystyrene-block-polybutadiene copolymers (SB) with 0.5 mass fraction of styrene were studied by electron spin resonance (ESR) of nitroxide spin probes. The influence of the block length ( and ) and the solvation power of casting solvents on the motional dynamics of spin probe were measured over a wide temperature range. Two nitroxide radicals as spin probes were selected: 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl benzoate (BzONO) and 2,2,6,6-tetramethyl-4-hydroxypiperidine-1-oxyl (Tempol). Irrespective of the spin probe used two ESR spectral components differing in their motional properties above the phase transition of polybutadiene blocks (PB) were observed. The fast component was assigned to spin probes located in polybutadiene-rich domains and the slow component to spin probes in polystyrene-rich domains. The range of two spectral components and the phase transition of the slow ESR component, T_5mT, depend on the block length. The influence of the interphase and accumulation of free volume in the interphase on the Tempol probe motion was investigated by changing copolymer morphology in the films casted from selective and nonselective solvents. The analysis of the motional heterogeneity from the ratio of the fast and slow motional component presents evidence that in the selective solvent for polystyrene (PS) blocks (2-butanone) the most irregular structure with a large interphase is formed. The difference in fast motion of spin probes indicates that the motional dynamic is related to the change of domain structure.     

P_2O_5和V_2O_5对CaO－Al_2O_3－SiO_2系统玻璃分相与析

Ｐ＿２Ｏ＿５和Ｖ＿２Ｏ＿５对ＣａＯ－Ａｌ＿２Ｏ＿３－ＳｉＯ＿２系统玻璃分相与析晶行为的影响膝立东，陆德明，甘朝亢（山东轻工业学院２５０１００）ＴｈｅＥｆｆｅｃｔｓｏｆＰ＿２Ｏ＿５ａｎｄＶ＿２Ｏ＿５ｏｎｔｈｅＰｈａｓｅｓｅｐａｒａｔｉｏｎａｎｄＣｒｙｓ...