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Carbonation Behavior Assessment of RH Slag Batch after Aqueous Extraction at Environmental Pressure

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Journal of Iron and Steel Research International 2014年第S1期21卷 74-81页

作者： An-jun XU Hui-ning ZHANG dong-feng he State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Metallurgy and Chemical Engineering Jiangxi University of Science and Technology

In order to assess CO2 sequestration amount and carbonation degree for RH slag at surrounding pressure, carbonation process of RH slag batch in lab is investigated, and the parameters of carbonation degree and CO2 sequestration amount are the targets, and the relationship between both and relevant factors, such as CO2 flow, gas bubble size etc. is originally discussed. The carbonation degree increases when temperature increases before 60 oC, then decreases. Particle size has a positive effect on carbonation degree, and carbonation degree for 0.5 L/min is bigger than those for 0.1 L/min and 1.0 L/min. When small gas bubble generator is adopted, carbonation degree and CO2 sequestration amount is improved. The maximum carbonation degree and CO2 sequestration amount is 34% and 178.65 g/kgslag, respectively when 38 μm RH slag batch is carbonated for 90 min at 60 oC under the conditions that CO2 flow is 0.5 L/min and bubble size equals 5 mm. CaCO3 and MgCO3 phases exists through XRD analysis, showing that carbonation process is effective. Carbonation degree model is established assuming carbonation reaction occurs on the active surface of RH slag batch. This model fits very well by comparison between experimental results and model results.

关键词： RH slag carbonation degree CO2 bubble size CO2 sequestration amount

Case-based reasoning model based on attribute w&ghts optimized by genetic algorithm for predicting end temperature of molten steel in RH

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Journal of Iron and Steel Research International 2019年第6期26卷 585-592页

作者： Kai feng An-jun Xu Peng-fei Wu dong-feng he Hong-bing Wang School of Metallurgy and Ecology Engineering University of Science and Technology Beijing 100083 China Beijing Key Laboratory of Knowledge Engineering for Materials Science University of Science and Technology Beijing 100083 China China Minmetals Corporation Beijing 100010 China School of Computer and Communication Engineering University of Science and Technology Beijing 100083 China

Temperature control is the key of Ruhrstahl-heraeus (RH) process in steelmaking plant. The accuracy of RH control model greatly affects the molten steel temperature fluctuation. To obtain RH control model with higher accuracy, an improved case-based reasoning (CBR) model based on attribute weights optimized by genetic algorithm (GA) was proposed. The fitness function in GA was determined according to the prediction accuracy of end temperature of molten steel in RH;then, GA is used to optimize all the attribute weights based on known case base. An improved CBR model that contains the optimized attribute weights was applied to predict end temperature of molten steel in RH, and the prediction accuracy wascalculated. Four methods, CBR based on attribute weights optimized by GA (CBR-GA), ordinary CBR, back propagation neural network (BPNN) and multiple linear regression (MLR) method were employed for comparison. The results show that in the error range of [- 3 ℃, 3 ℃],[- 5 ℃, 5 ℃],[- 7 ℃, 7 ℃] and [- 10 ℃, 10 ℃], the prediction accuracy of CBR-GA was improved by 19.99%, 28.19%, 27.11% and 16.3%, respectively, than that of MLR. Compared with BPNN, the prediction accuracy increased by 3.22%, 7.44%, 5.29% and 2.40%, respectively. Compared with ordinary CBR, the accuracy increased by 5.43%, 5.80%, 4.66% and 2.27%, respectively.

关键词： Case-based reasoning Genetic algorithm End temperature prediction RH process Molten steel

Hybrid Model of Molten Steel Temperature Prediction Based on Ladle heat Status and Artificial Neural Network

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Journal of Iron and Steel Research International 2014年第2期21卷 181-190页

作者： Fei he dong-feng he An-jun XU Hong-bing WANG Nai-yuan TIAN School of Metallurgical and Ecological Engineering University of Science and Technology Beijing State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Computer and Communication Engineering University of Science and Technology Beijing

Aiming at the characteristics of the practical steelmaking process, a hybrid model based on ladle heat sta- tus and artificial neural network has been proposed to predict molten steel temperature. The hybrid model could over- come the difficulty of accurate prediction using a single mathematical model, and solve the problem of lacking the consideration of the influence of ladle heat status on the steel temperature in an intelligent model. By using the hybrid model method, forward and backward prediction models for molten steel temperature in steelmaking process are es- tablished and are used in a steelmaking plant. The forward model, starting from the end-point of BOF, predicts the temperature in argon-blowing station, starting temperature in LF, end temperature in LF and tundish temperature forwards, with the production process evolving. The backward model, starting from the required tundish tempera- ture, calculates target end temperature in LF, target starting temperature in LF, target temperature in argon-blo- wiag station and target BOF end-point temperature backwards. Actual application results show that the models have better prediction accuracy and are satisfying for the process of practical production.

关键词： steelmaking process hybrid model ladle heat status neural network molten steel temperature prediction

Preparation of Copolymer of Salen-crown Ether Complexes and its Catalytic Activation for Molecular Oxygen

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Chinese Chemical Letters 2006年第2期17卷 265-268页

作者： Rong Min WANG Xiao dong LI Yu feng he Gansu Key Laboratory of Polymer Materials Northwest Normal University Lanzhou 730070

A new stable salen Schiff base cobalt and crown ether sodium complex （SalCo-NaB18C6） was prepared through copolymerization. This copolymer complex was applied to catalytic oxidation of hydrocarbon compound with molecular oxygen without reductant, which was shown the higher activity and selectivity for ketone, and reused effectively.

关键词： Copolymeric complexes cyclohexene catalysis salen Schiff base crown ether.

Effect of FeO on the formation of spinel phases and chromium distribution in the CaO-SiO_2-MgO-Al_2O_3-Cr_2O_3 system

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International Journal of Minerals,Metallurgy and Materials 2013年第3期20卷 253-258页

作者： Jian-li Li An-jun Xu dong-feng he Qi-xing Yang Nai-yuan Tian State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Division of Sustainable Process Engineering Lule University of Technology

Synthetic slag samples of the CaO-SiO2-MgO-A1203-Cr203 system were obtained to clarify the effect of FeO on the formation of spinel phases and Cr distribution. X-ray diffraction （XRD） and scanning electron microscopy （SEM） equipped with energy-dispersive spectroscopy （EDS）, as well as the thermodynamic software FactSage 6.2, were used for sample characterization. The results show that the addition of FeO can decrease the viscosity of molten slag and the precipitation temperatures of melilite and merwinite. The solidus temperature significantly decreases from 1400 to 1250℃ with the increase of FeO content from 0wt% to 6wt%. The addition of FeO could enhance the content of Cr in spinel phases and reduce the content of Cr in soluble minerals, such as merwinite, melilite, and dicalcium silicate. hence, the addition of FeO is conducive to decreasing Cr leaching.

关键词： stainless steel slags spinel phase chromium leaching ferrous oxide

Improvement in the Hit Ratio of the Yield Strength of HRB400D Reinforced Bar

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Journal of Iron and Steel Research International 2014年第S1期21卷 28-33页

作者： dong-feng he Peng XUE Jin-bao CHANG Shuang-wu LI You-bing XIANG State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgy and Ecology Engineering University of Science and Technology Beijing Tangshan Iron and Steel Company of hebei Iron and Steel Group

The hit ratio of the yield strength of HRB400 D reinforced bar(Tangshan Iron and Steel Co.) is low. In this study, the effects of [C], [Mn], [Si], and [V] on the yield strength and mechanism were investigated. The HRB400 D reinforced bar with a specification of 22 spiral was chosen. A narrow composition control was achieved by reducing the lower limit of the Mn content and the amount of the alloying elements; moreover, the hit ratio of the reinforced bar yield strength increased from 65.54% to 96.27%, enhancing product stability. The cost of the steel alloy reduced by 8.86 RMB/ton, improving the market competitiveness of the product.

关键词： HRB400D narrow composition control yield strength hit ratio

The BMO_L Space and Riesz Transforms Associated with Schrdinger Operators

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Acta Mathematica Sinica,English Series 2010年第4期26卷 659-668页

作者： Jian feng dong he Ping LIU LMAM School of Mathematical Sciences Peking University Beijing 100871 P. R. China

Let L =△ ＋ V be a SchrSdinger operator in Rd, d ≥ 3, where the nonnegative potential V belongs to the reverse HSlder class Sd. We establish the BMOL-boundedness of Riesz transforms З/ЗxiL-1/2, and give the Feffe... 详细信息

关键词： BMO space reverse HSlder class Schr5dinger operator Riesz transform

Temperature Holding Hood for Hot Charging of Continuous Casting Slab in Tangshan Iron and Steel Company

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Journal of Iron and Steel Research International 2014年第S1期21卷 34-38页

作者： dong-feng he Xiao-nan YU Jin-bao CHANG You-bing XIANG Zong-yu XUAN State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgy and Ecology Engineering University of Science and Technology Beijing Tangshan Iron and Steel Company of hebei Iron and Steel Group

To improve the charging of high-temperature billets, it is crucial to produce them with zero defects and achieve effective insulation during their hot delivery. A mathematical model was developed based on the heat transfer characteristics of the billet during its hot delivery. The accuracy of the model was established by studying the thermal performance of the cover of the roller conveyer for small billets in Tangshan Iron and Steel Company. The results show that the cover of the roller conveyer of the continuous casting billet can effectively reduce the heat loss during the hot delivery of the billets, and the hot loading temperature was increased by 51.6 °C. The uniformity of the temperature of the casting billet section increased substantially. The temperature difference in the casting billet section was reduced by 120 °C. The heat preservation effects of temperature holding hoods of different materials were compared. It was found that the material of the temperature holding hood has slight effect on the heat preservation.

关键词： billet hot charging temperature holding hood temperature energy saving

Carbothermic Reduction of Zinc and Iron Oxides in Electric Arc Furnace Dust

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Journal of Iron and Steel Research International 2014年第4期21卷 427-432页

作者： Hui-ning ZHANG Jian-li LI An-jun XU Qi-xing YANG dong-feng he Nai-yuan TIAN School of Metallurgy and Chemical Engineering Jiangxi University of Science and Technology Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and Technology Metallurgical and Ecological Engineering School University of Science and Technology Beijing Division of Extractive Metallurgy Lule University of TechnologyLule SE-971 87Norrbottens LnSweden

The reduction of zinc and iron oxides from electric arc furnace dust （EAFD） by carbon was investigated at temperatures between 800 and 1300℃. The analytic technique employed includes chemical analysis, X-ray fluores- cence spectroscopy （XRF）, X-ray powder diffraction （XRD）, scanning electron microscopy （SEM） equipped with X-ray energy dispersive spectrometry （EDS）, and thermodynamic database FactSage 6.2. It was found that the reduction of zinc and iron oxides depends largely on Boudouad reaction. At 900℃, zinc exists in tested samples as ZnO, which is reduced in the temperature range of 1000--1 100℃. At 1 100℃, 99.11% of the zinc is evaporated. The metallization ratio of Fe is 79.19% at 1300℃, as the content of Fe2＋ is still 9.40%. A higher temperature is thus required for a higher reduction degree of Fe oxides by solid or gaseous carbon.

关键词： electric arc furnace dust reduction ZnO ZnFe204