纳米Fe粉的制备研究

总结了纳米Fe粉的制备方法,重点介绍了一种新的制备方法——封闭循环氢还原法。该方法以FeSO·47H2O和NaOH为原料,采用沉淀方法制备粒径为30～70nm的Fe2O3粉末,其反应条件为:反应温度50℃,反应终点pH值大于12,陈化时间1h。用封闭循环氢还原法,在400℃下还原Fe2O3得到了Fe粉。其粒径在20～50nm之间,含量为99.16%。     

天津钢管公司DRC直接还原厂生产工艺与自动控制

天津钢管公司DRC直接还原厂将采用英国戴维国际工程公司的DRC煤基直接还原技术,以铁矿石、煤、石灰石为原燃料,用回转窑来生产直接还原铁(DRI)。该厂将由两条回转窑生产线组成,每条生产线的生产能力为15万tDRI/年,回转窑规格为φ5.0m×80m。工厂生产主线将采用计算机集散控制系统(DCS)以实现对生产过程的自动控制。     

Reduction of Stibnite at Moderate Temperature

Reduction of stibnite with hydrogen in the presence of calcium oxide has been experimentally inves-tigated at moderate temperature. The results reveal that the effluent generated in the reduction pro-cess contains much less air-polluting substance H_2S, and that the reaction activation energy is63. 3 kJ/mol. The form of antimony changes considerably when the reaction temperature varies.     

熔融还原炉内二次燃烧和传热

总结了熔融还原炉内二次燃烧和传热的研究成果，对于转炉采用二次燃烧提高废钢比也有借鉴作用。     

Air Filtration and Radon Decay Product Mitigation

Air cleaning as a means of mitigating the risks arising from exposure to indoor radon progeny has been evaluated in a single-family house in the north eastem US. using an automated, semi-continuous activity-weighted size distribution measurement system. The measurements included radon concentration, condensation nuclei count, and activity-weighted size distribution of radon decay products. Measurements were made in the house with and without an operating air filtration system and with various particle sources common to normal indoor activities operating. Aerosols were generated by running water in a shower, candle burning, cigarette smoking, vacuuming, opening doors, and cooking. Using a room model, the changes in attachment rates, average attachment diameters, and deposition rates of the unattached fraction with and without the air cleaning system were calculated. In the presence of active aerosol sources, the air filtration unit typically reduced the concentration of particles within the hour following the end of particle generation. After candle burning, cigarette smoking, and vacuuming in the bedroom, the reductions of PAEC by air filtration are about 60% with the air filtration system operating in the bedroom. During cooking in the kitchen, the reductions of PAEC in the bedroom with the air filtration system were about 40%. However, for all cases the dose reductions were smaller than the particle and PAEC reductions. For those particles that were generated within the bedroom, there was a 20% to 50% reduction in dose. In the case of cooking where the door was open and particles infiltrated from the rest of the house, the dose reduction was only 5% on average and appears to be insignificant. Thus, the dose reductions were h e r than the reductions in activity concentration, but there were no cases where the estimated dose actually increased.     

Two dimensional deformation characteristics of bloom CC with liquid core reduction

A two-dimensional model was applied to simulate the liquid core reduction(LCR) technology of bloom CC using ANSYS software.The deformation characteristics of bloom under different liquid fraction and reducing amount are obtained.The results indicate that the main deformation condition of bloom shell is compressive strain,mainly undertaken by the liquid core,which increases with the enhancement of reducing amount.Solidified shell takes minor deformation.The longitudinal section of bloom appears sunken and the narrow side bulges,which grow serious when the liquid fractionincreases.     

核壳型铁钴纳米复合材料的制备及其性能

采用多元醇还原工艺和自组装技术,在微米级Fe粉表面包覆纳米Co粒子,一步法制备了一种具有核壳结构的复合磁性微球,用SEM表征了其相组成和形貌,用VSM测试了磁滞回线,初步研究了磁学性能。结果表明:用该法制备的核壳型Fe/Co纳米复合材料表面包覆致密,其比饱和磁化强度和矫顽力介于微米铁粉和纳米钴粉之间。     

Insight into the chemical reaction of CH2OH with NO: Formation of N-hydroxy formamide as an isocyanic acid precursor

This study has explored the potential energy surface on the chemical reaction of CH₂OH with NO by using ab initio calculation. We have found the new reaction pathway producing N-hydroxy formamide, which can further decompose to generate isocyanic acid as a reducing agent of hydrocarbons selective catalytic reduction.     

Construction of transmission lines above valuable standing timber

Problems with the construction of transmission lines above a forest are examined. Construction of lines above standing timber makes it possible to shorten the length of the route, eliminate the clearing of a continuous swath along the line, and reduce the volume of in-service work. To implement this solution, it is necessary to introduce changes and supplements to existing regulatory technical documents. __________ Translated from élektricheskie Stantsii, No. 10, October 2007, pp. 48–51.