2001 Vol. 8, No. 1

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Mineral
Study on copper adsorption on olivine
Rolf A. Kleiv, Lei Shao, Kunt L. Sandvik, Wei Wu, and  Cunyi Song
2001, vol. 8, no. 1, pp. 1-5.
Abstract:
The copper adsorption on olivine supplied by A/S Olivine production plant at Aheim in western Norway has been studied. The factors which affect the uptake of copper have been evaluated. The results reveal that the equilibrium PH in aqueous solution has the greatest influence on the copper adsorption thanks to the competitive adsorption between proton and copper ions, and the adsorption of copper to olivine increases rapidly with the pH increasing from 4 to 6. The initial copper concentration and olivine dose also possess significant effect on copper adsorption. The adsorption efficieny of copper increases with the increase of olivine dose or the decrease of initial copper concentration at the same pH. The ionic strength effect on the adsorption has also been investigated, but it owns little effect on the adsorption process of copper due to the formation of inner sphere surface complexation of copper on olivine. The experimental data show that olivine has a high acid buffer capacity and is an effective adsorbent for copper.
Mineral
Fluid Inclusions and Daughter Minerals of Taibai Gold Deposit, ShaanXi Province, China
Yuling Xie, Jiuhua Xu, Dayi Qian, and  Jianping Li
2001, vol. 8, no. 1, pp. 6-9.
Abstract:
A discovery of daughter minerals in fluid inclusions of Taibai gold deposit, Shaanxi province has been focused on, which is a unique breccia-cemented gold-bearing system. The breccia zone strikes NWW-SEE, occurring in Devonian strata of Southern Qinling Mountains. The cement is mainly composed of ankerite, pyrite, calcite and quartz, which may be divided into four main tectonic-mineralizing stages. Gold mainly occurs in pyrite and ankerite of stage II and IV. It is found that three types of fluid inclusions can be distinguished: (1) aqueous inclusions (type B); (2) CO2-rich inclusions (type C); (3) daughter minerals-containing inclusions (type A). LRM. (Laser Raman Micro-probe) analyses shows that the content of CO2 occupies 54.4%-70.7% (mole fraction, so as the follows) in vapor phases of different type fluid inclusions. CH4 (5.2%-7.3%) and H2S (6.0%-12.7%) exist in both vapor and liquid phases. Many daughter minerals in fluid inclusions of ankerite and quartz have been found. Several kinds of daughter minerals, including ankerite, pyrite, arsenopyrite and halite, were determined by using SEM (scanning electron microscope)/EDS (energy dispersive spectrometer) technique. EPMA (electron probe micro-analysis) technique was also applied to study the daughter minerals exposed to the surface of polished thin sections.
Mineral
Relationship between Environmental Pollution of Coal Mine and Spectral Characteristics of Nearby Plants
Liqing Lei
2001, vol. 8, no. 1, pp. 10-14.
Abstract:
Remote sensing technology, as the most advanced method for collecting data, along with the common ways often used in the past on research of environmental science, was integrated to study the relationship between environmental pollution of coal mine and spectral characteristics of nearby plants. With compositive index and mean reflectivity at near infrared, a regression equation was established, and a conclusion was made that spectral reflectivity can be used to distinguish regions with different pollution degree. Through testing with real status of the research region, it is verified that this kind of integration and conclusion not only are helpful for human being in controlling the movement law of pollutants and the corresponding change of coal mine environmental quality but also bring a new way for the research of environment problems of coal mine.
Metallurgy
A Back Look on the Binary Phase Diagrams of Metals from the Mass Action Law and the Coexistence Theory of Metallic Melts
Jian Zhang
2001, vol. 8, no. 1, pp. 15-19.
Abstract:
According to the mass action law and the coexistence theory of metallic melts, the mass action concentrations of Cu-Mg, Bi-Tl and Ni-Al melts involving compound formation have been calculated. The calculated results show that, except the ultimate case of pure element, when two elements are present in the melts, all structural units (atoms and molecules) without exception will be present in the melts, i.e., their concentrations may change from great to small, but they will not vanish into nothing, and only under such conditions, the calculated results both agree with practice and obey the law of mass action. In view of that over considerable wide composition range, the activities of both elements of the three solid binary alloys mentioned above have been measured, this seems in contradiction with the present relevant phase diagrams, in which the structural units are determined by composition range, so the latter needs further investigation and consideration.
Metallurgy
A New High Quality EAF Charge
Jianliang Zhang, Yuquan Liu, Zongwang Zhang, Jinlin Jia, and  Yongmei Zhang
2001, vol. 8, no. 1, pp. 20-21.
Abstract:
In order to solve the problem of the shortage of scrap, especially high quality scrap, granular pig iron, a new substitute for scrap or DRI (direct reduction iron) has been developed. The technical process of decarbonized granular pig iron has been evaluated. The result shows that this new process is superior to direct reduction process in product quality, construction investment, operation flexibility, production efficiency etc. Decarbonized granular pig iron (DGPI) not only can be used as conventional scrap but also can be charged into EAF as high purity burden equivalent to heavy scrap.
Metallurgy
Experiment Study on Castex Process of AS Wire
Zhiyuan Shi, Wanjun Wang, Jinglin Wen, and  Xinhua Wang
2001, vol. 8, no. 1, pp. 22-24.
Abstract:
In order to optimize the Castex process of AS wire, the systematic experiments have been done for different process parameters with self-made DZJ-II 350 Castex machine. The parameters, such as casting temperature of aluminum, flow of cooling water, extrusion ratio and the gap between the surface of wheel and that of the mould, have been mainly studied. The results show that with the increase of casting temperature or rotating speed of wheel the measured length of liquid metal zone increases too. However, the length of liquid metal zone decreases with the increase of the flow of cooling water. Moreover, the relationship between the extrusion ratio and the extrusion power is studied.
Metallurgy
Study on Oxygen Content, Inclusions and Fatigue Properties of Bearing Steels Produced by Different Processes
Deguang Zhou, Jie Fu, Xichun Chen, and  Jing Li
2001, vol. 8, no. 1, pp. 25-27.
Abstract:
The metallurgical properties and fatigue life of bearing steel processed by electric furnace (EAF), ladle refining (LF-VD), continous casting (CC) and electroslag remelting (ESR) have been investigated. The main results obtained are as follows: (1) Due to low oxygen content and dispersion inclusions in steel, the fatigue Life of LF-VD-IC or CC is three times as high as that of EAF steel; (2) The oxygen content in steel produced by CC process is about 9.0×10-6, the carbon segregation (C/C0) is from 0.92 to 1.10 and the fatigue life of CC steel is equal to that of ladle refining ingot casting steel; (3) Although the amount of inclusion and oxygen in ESR steel is higher than that of LF-VD-IC or CC steel, the fatigue life of ESR steel is higher than that of the latter because of its fine and well dispersed inclusions.
Materials
Preparation and High Temperature Oxidation Properties of Micro-crystalline MGH754 ODS Alloy Coatings
Huibub Qi, Hongmei Pang, Yedong He, Deren Wang, and  Wei Gao
2001, vol. 8, no. 1, pp. 28-34.
Abstract:
A special coating technique, electro-spark deposition (ESD), was developed to produce micro-crystalline ODS MGH754 alloy coatings on a commercial 1Cr18Ni9Ti stainless steel and a cast Ni20Cr alloy substrates. The coatings have a very fine grain structure and metallurgical bonding with the substrates. The isothermal oxidation tests at 1000 ℃ in air showed that the micro-crystalline ODS alloy coatings had a much reduced oxidation rate and improved scale spallation resistance compared with the uncoated alloys. The selective oxidation of Cr was greatly promoted to form protective and continuous Cr2O3 scales on the alloy surface. Micro-crystallization and oxide dispersions have synergistic effects on the improvement of oxidation resistance. The beneficial effects were discussed based on the experimental results.
Materials
TEM Study on Hydrogen-Induced Cracking of Fe3Al Alloy
Biao Gu, Lijie Qiao, and  Wuyang Chu
2001, vol. 8, no. 1, pp. 35-38.
Abstract:
Hydrogen-induced cracking (HIC) of Fe3Al alloy was studied by in situ transmission electron microscope (TEM). Electron transparent specimens were mounted onto a constant displacement device. Stress was applied to the specimen by using a bolt through the device. The results showed that hydrogen enhanced the dislocation emission and motion in Fe3Al alloy. A dislocation free zone (DFZ) was formed following the dislocation emission. Microcrack initiated in the DFZ or at the main crack tip when the emission reached a critical extension. Hydrogen played an important role in the process of brittle fracture of Fe3Al alloy.
Materials
GTA Welds of Iron-Aluminide Based Alloys
Dechun Gao, Wangyue Yang, Min Dong, Jihua Huang, Yuanding Huang, and  Zuqing Sun
2001, vol. 8, no. 1, pp. 39-42.
Abstract:
The weldability of two Fe3Al-based intermetallic alloys and one Fe-16%Al-based (atom fraction) alloy has been investigated for gas tungsten are (GTA) welding on sheets with a thickness of 2 mm. The results indicated that pre-heating and post-annealing treatment were important procedures for retarding cold crack initiation and the propel selection of filler could effectively improve the weldability. For the same alloys with the same welding filler, it is better to choose lower welding current, in another word, lower heat input.
Materials
Oxidation of O'-SiAlON-ZrO2 Composite Ceramics
Xidong Wang, Hong Bao, and  Wenchao Li
2001, vol. 8, no. 1, pp. 43-47.
Abstract:
The oxidation kinetics of O'-SiAlON-ZrO2 composite ceramics in the temperature range of 1373-1773K has been studied. The oxidation experiments with powder and plates of O'-SiAlON-ZrO2 composite ceramics in air have been carried out. The overall activation energy of oxidation reaction is 263.69 kJ/mol. The products and structures of O'-SiAlON-ZrO2 oxidation layer have been analysed by XRD (X-ray diffraction), SEM (scanning electron microscope) and AFM (atomic force microscope).
Materials
Design and Synthesis of Ti-ZrO2 Functionally Graded Materials
Lidong Teng, Fuming Wang, and  Wenchao Li
2001, vol. 8, no. 1, pp. 48-52.
Abstract:
Functionally graded materials (FGMs) based on titanium-zirconia system have been prepared by powder metallurgical method. The graded interlayer number and the compositional distribution have been designed by elastic finite element method. The interfacial microstructure between layers, the combining state of phases between Ti and ZrO2 have been investigated by means of XRD (X-ray diffraction), SEM (scanning electron microscope), EDS (energy dispersive spectrometer) and so on. The co-existing region of Ti and ZrO2 has been determined by thermodynamic calculation to control the sintering atmosphere. The experimental results show that the joint between Ti and ZrO2 phases is physical in this composite and ZrO2 mainly exists as tetragonal phase. The microstructure of Ti-ZrO2 system FGM exhibits a transition from a zirconia particle dispersion in a titanium matrix to an inverse dispersion of titanium in zirconia. The gradient structure of titanium and zirconia can relieve thermal stress.
Materials
Relationship between Ballistic Coefficient and Static Mechanical Properties for Armor Materials
Junpin Lin, Yong Zhang, Zhi Lin, and  Guoliang Chen
2001, vol. 8, no. 1, pp. 53-54.
Abstract:
The relationship between the ballistic coefficient and the static mechanical properties of armor materials was studied. The results show that the ballistic coefficient is determined by the strength, hardness and the toughness of materials. According to the Martel rule, the equation of the relationship between ballistic coefficient and static mechanical properties satisfies the following formula: \[{W_{\rm{s}}} = M(1 + N\frac{{{K_{{\rm{IC}}}}}}{\rho }){H_{\rm{T}}}\]. From the mixture law of composite, the prerequisite, for which ballistic coefficient has maximum to reinforcement volume fraction, is obtained by the following equation: \[\frac{{{\rm{d}}{W_{\rm{S}}}}}{{{\rm{d}}f}} = b({K_1}{\rho _0} - {K_0}{\rho _1})\frac{H}{{{\rho ^2}}} + (a\frac{K}{\rho })({H_1} - {H_0})\].
Materials
Recrystallization of High Carbon Steel during High Strain Rate
Di Tang, Qingwu Cai, Yueqin Li, Yumei Pu, and  Yuzhou Zhu
2001, vol. 8, no. 1, pp. 55-58.
Abstract:
The recrystallization of high carbon steel during high temperature and high speed rolling has been studied by analyzing the stress-strain curves and the austenite grain size. Isothermal multi-pass hot compression at high strain rate was carried out by Gleeble-200D. The austenite grain size was measured by IBAS image analysis system. The results show that static recrystallization occurred at interpass time under pre-finish rolling, and at the finish rolling stage, due to the brief interpass time, static recrystallization can not be found.
Materials
Thermal Behaviors of Work Roll in Finishing Trains of Hot Rolling
Anrui He, Jie Zhang, Chen Zhang, Qingdong Zhang, Gangcheng Wei, and  Siqing Huang
2001, vol. 8, no. 1, pp. 59-62.
Abstract:
In order to analyze the thermal field and thermal contour of work roll in finishing trains of hot rolling in rolling process, a quasi two-dimension implicit finite difference model is developed. To improve the calculating speed and precision, some special solutions are introduced, including the development of this model, the simplification of boundary conditions and the computation of heat transfer coefficients. The results show that these solutions of thermal behaviors of work roll are very much efficient and the model can be used as an on-line profile and fatness control model of large industrial mills.
Information
A New Genetic Algorithm Based on Niche Technique and Local Search Method
Jinwu Xu and  Jiwen Liu
2001, vol. 8, no. 1, pp. 63-68.
Abstract:
The genetic algorithm has been widely used in many fields as an easy robust global search and optimization method. In this paper, a new generic algorithm based on niche technique and local search method is presented under the consideration of inadequacies of the simple genetic algorithm. In order to prove the adaptability and validity of the improved genetic algorithm, optimization problems of multimodal functions with equal peaks, unequal peaks and complicated peak distribution are discussed. The simulation results show that compared to other niching methods, this improved genetic algorithm has obvious potential on many respects, such as convergence speed, solution accuracy, ability of global optimization, etc.
Information
Rolling Element Bearing Diagnostics by Combination of Envelope Analysis and Wavelet Transform
Ying Tang and  Qiao Sun
2001, vol. 8, no. 1, pp. 69-74.
Abstract:
Rolling element-bearing diagnostics has been studied over the last thirty years, and envelope analysis is widely recognized as being the best approach for detection and diagnosis of rolling element bearing incipient failure. But one of the on-going difficulties with envelope technique is to determine the best frequency band to envelop. Here, wavelet transform technique is introduced into envelope analysis to solve the problem by capturing bearing defects-sensory scales (i.e. frequency bands). A modulated Gaussian function is chosen to be the analytical wavelet because it coincides well with bearing defect-induced vibration signal patterns. Vibration signals measured from railway bearing tests were studied by the proposed method. Cases of bearings with single and multiple defects on inner and outer race under different testing conditions are presented. Experimental results showed that the proposed method allowed a more accurate local description and separation of transient signal part, which were caused by impacts between defects and the mating surfaces in the bearing. The combination method provides an effective signal detection technique for rolling element-bearing diagnostics.
Information
Synthetical Control of AGC/LPC System Based on Neural Networks Internal Model Control
Hu He, Xiaodong Luan, and  Yikang Sun
2001, vol. 8, no. 1, pp. 75-77.
Abstract:
One synthetical control method of AGC/LPC system based on intelligence control theory-neural networks internal model control method is presented. Genetic algorithm (GA) is applied to optimize the parameters of the neural networks. Simulation results prove that this method is effective.