Frontiers of Materials, Chemical and Metallurgical Technologies

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Authors: Liang Chen, Tian Ming Chen, Yong Chen, Yao Xian Zeng, Ping Fan Li
Abstract: In consideration of inclusion control in smelting drilling steel SAE4137 by convert process, the software FACTSAGE is applied on the deoxidation technology, composition of ladle slag and calcium treatment technology. The tests show that the deoxidation technology is reasonable and the oxygen content of molten steel is not more than 5×10-6 and 3.2×10-6 on average. The inclusion of bar is less and like a ball. The effect of calcium treatment is good. The inclusion is transformed in refining process, the absorbing ability to inclusion of ladle slag is strong. The level of any type of inclusion is not more than 1.5. The mechanical performance of SAE4137 bar meets the requirements, and the inclusion control technology does not influence the mechanical performance of bars.
861
Authors: Chen Liu, Hang Jun He, Duo Qiang Liang, Han Huang, Lu Man Man, Yu Song, Si Qiang Luo
Abstract: Zinc neutral leaching residue from conventional roast-leach-electrowin often contains a considerable content of germanium. In two-stage leaching process (weak acid leaching and hot acid leaching), dissolution yield of germanium as well as zinc is low due to the compact structure of the residue. In the paper, an attempt of increasing their dissolution yield was made by pretreatment of mechanical activation. The experimental results obtained show that the activated residue has much faster leaching kinetics, and that according to current technical standard operating in Yunnan Chihong Zinc & Germanium Co., Ltd, dissolution of germanium and zinc is increased by 18.12% and 22.93%, respectively. The increase may mainly be due to the structure deformation of the residue by further investigation.
868
Authors: Yong Cheng
Abstract: With the utilization of hydrofluoric acid and nitric acid, vanadium oxide samples such as V2O5 and V2O3 are digested by the way of high-pressure closed microwave heating and 22 impurity elements with concentration of 0.0001% ~ 0.5% including Nb, Zr, Ti, W, Si, Al, Mo, Co, Cr, Ni, Cu, Pb, Cd, As, P, Fe, Mn, Ca, Mg, Na, K and B are directly and simultaneously determined by inductively coupled plasma mass spectrometry (ICP-MS). The optimum microwave digestion conditions, combination and ratio of the digestion reagents, optimization of detection conditions, matrix effects, mass interferences and other influencing factors are investigated; in order to eliminate the mass spectrum interference from vanadium matrix isobars and polyatomic ion formed by combination of these isobars and Ar, O, H and other atoms, isotopes of the test elements with high abundance sensitivity and little interference are selected for analysis of elements; the analyte is divided into two mass regions, respectively using Sc and Rh as internal standard for the correction of matrix effects. The results show that: V2O5, V2O3 and impurities contained in the matrix can be quickly and completely digested, thus, insoluble oxides or volatile impurities such as Nb, Zr, Ti, W, Si, Al, Cr and As can be digested without a loss; the stability and precision of continuous determination is significantly improved by Sc and Rh internal standard correction method, and matrix effects, interface effects and other effects generated in high vanadium-based matrix are effectively eliminated. The test also boosts a detection limit of 0.01 ~ 0.89μg /L, correlation coefficient r ≥ 0.9991, recovery rate of 90% ~ 113% and RSD <5%. This method can meet the need to simultaneously determine 22 kinds of micro, trace and ultra-trace impurities of various normal or high-purity V2O5, V2O3 and other vanadium oxides.
873
Authors: Lei Cao, Xue Tong Li, Shu Jian Liu, Min Ting Wang
Abstract: A new groove design method of uniform strong strain of bar rolling was proposed based on the principle of strong plastic deformation to manufacture ultra-fine grain(UFG), and flat-oval groove type with the characteristics of big crushed and multidirectional deformation was set up. The numerical analysis model of hot continuous bar rolling process was created using nonlinear finite element method. The study of the law of plastic strain distribution after each rolling pass of the caliber series indicated that the caliber can satisfy with the precise size and shape, and can also better introduce the plastic strain to the center of cross section and get uniform strong strain. The largest strain was more than 5.0 in the center of cross section, in which condition ultra-fine grain can be fabricated. Therefore, this study provides important theoretical basis for the ultra-fine grain of bar rolling development.
879
Authors: Shi Long Tian, Zhi Li Yang
Abstract: By establishing finite element mathematical model for heat transfer in the ladle to simulate transient temperature distribution field, this paper, with typical value method and energy conservation method, studies effect of ladle preheating temperature and insular linings of the ladle on molten steel temperature drop in the 210 t ladle used by Chongqing Iron & steel Co., Ltd. Furthermore, decrease rate of molten steel temperature is forecasted under different working conditions. These predicted results are compared to those obtained by temperature measurements on the site, which shows that ladle preheating temperature affects the rate of molten steel temperature drop a lot, and the decrease rate of molten steel temperature in casting state is greater than in holding state of molten steel. Actual temperature decrease rate of molten steel on the site is between one obtained by energy conservation method and one obtained by typical value method. These studied conclusions provide good reference for molten steel temperature control in Chongqing Iron & Steel Co, Ltd.
883
Authors: Yi Xing, Fan Zhao, Chen Hong, Guang Wei Yu, Cheng Sheng Yue, Yan Xiao Si
Abstract: This paper discusses the feasibility of the lime-mediated sewage sludge replace the fuels and flux as metallurgy ingredients, the influence of lime-mediated sewage sludge used in metallurgy sintering process to the sinter performance. The calorific value of the sludge was 4.67MJ/kg. The X-ray diffraction (XRD) showed that the main existing form of Calcium in the lime-mediated sewage sludge is CaCO3 at 550°C, and almost is CaO at 1100°C. This provided the basis to the sludge used as sintering ingredients. Sintering cup experiment results showed that Lime dry sludge have a positive impact on sintering, the sinter quality indexes are improved. When sludge ratio is 3.00%, the vertical sintering burning rate is 21.28mm/min, the yield is 72.62%, the utilization coefficient is 1.455T/m2•h, fuel consumption from 65.65kg/T fall to 59.16kg/T, then concluded that the flux and fuel ratio replaced by lime-mediated sewage sludge were 43.3%, 13.3% respectively.
888
Authors: An Lin Li, Xin Teng Liang, Yong Chen, Jian Hua Zeng, Gui Jun Li, Sen Xiang Yang
Abstract: Focus on such problems as low supplying capacity, short furnace life and poor smelting effect during extracting vanadium using combined blowing converter, the structure optimization of bottom blowing brick used to ventilating was studied, the system used to supplying gas was implemented, and the crafts of extracting vanadium with combined blowing technology was developed as well as the protecting technology of brick used to ventilating was applied. The results show that strength of gas supplying of BOF is increased to at least 0.10m3/ (min•t). The combined blowing lifetime is extended, especially reaches to 7455 heats. The proportion of multiple blowing is reached to 100%. The quality o f vanadium slag is improving obviously.
895
Authors: Long Kui Jiang
Abstract: Based on feature of low-sulphur steel smelting in PanGang, in terms of optimizing desulfurization technology, reducing resulfurization in converter steelmaking, optimizing desulfurization in LF molten steel refining process and developing RH molten steel refining desulfurization technology. The sulphur content of hot metal can be controlled no more than 0.003%, and that of terminal molten steel can also be controlled no more than 0.005%, which makes the production of low-sulphur steel come true, and the technology route of such steel smelting be established.
899
Authors: Wei Gao, Cheng Yan Wang, Fei Yin, Yong Qiang Chen, Wei Jiao Yang
Abstract: The present paper reviews the situation and technology progress of lead smelting in China. According to the new lead smelting processes, this paper also presents a lead oxygen-enriched flash smelting technology, whose intellectual property rights are completely owned by China,it points out that lead smelting processes develop as follow: lower environmental pollution, higher metal recovery rate, more effective for complex low grade lead-bearing ore materials, lower energy consumption and higher automation degree.
904
Authors: Xi Yuan Shuai, Chao Wu
Abstract: Experiments were carried out by rolling pure iron at ultra high rolling speed. Results showed that the grain size of the rolled products in certain areas is corresponded by the grain size of the matrix. The deformation of rolled metal does not only occur at the surface, but also penetrate to the center when rolling speed is set >100m/s with the corresponded strain rate >2800 S-1. The grain size of the rolled products fits well with the matrix (billet) if distributed evenly. The longitudinal section parallel to rolling direction is analyzed by optical microscope. The grains near the center were stretched in vertical direction, while the ones around the surface were compressed. This is determined by the unique character of groove rolling.
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