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By Yang Xianwan, Zhu Xiaoyun, Guo Zhongcheng, Zheng Yanping, Zhai Dacheng

"Corrosion resistance of RE-Ni-W-P-SiC composite coating and 3 l6L stainless steel in corrosion media of H2SO4, HCl, H3PO4 and FeC13 solutions at different concentrations by means of immersion methods and anodic polarization curves obtained by DHZ-1 electrochemical synthetic tester and HDV-7 transistor constant potentiometer. Immersion experiment results show that corrosion rate of RE-Ni-W-P-SiC composite coating as-deposited in HCl solutions increases with the rise of HCl concentrations, on the contrary, the corrosion rate of the composite coating after heat treatment decreases with increasing the HCl concentrations the corrosion rates of the coatings as-deposited and after heat treatment in H2SO4 and H3PO4 solutions respectively decrease with the rise.of H2SO4 and H3PO4 concentrations the corrosion rate of the deposit as-deposited in FeC13 solutions decreases with increasing FeC13 concentrations, while the rate of the composite coating after heat treatment increases .with the rise of FeC13 concentrations.In addition, the corrosion rate of 3 l 6L stainless steel in the corrosion media of H2SO4, HCl, H3PO4 and FeC13 solutions at different concentrations increases with rising of concentrations. Furthermore, the corrosion rate of 316L stainless steel in the corrosion media of H2SO4, HCl, H3PO4 and FeC13 solutions respectively is much greater than that of the RE-Ni-W-P-SiC composite coating as-deposited and after heat treatment in the same corrosion media.1. IntroductionAll the materials and their products, when processed, stored and used, it is inevitable that the corrosion, wear, fatigue and crack occur owing to the actions of surroundings. Those early failure and abrasion, through all kinds of departments and profession that corrosion consumes one percent of tens of the steel products of the whole world; and two or four percent of the GDP is lost because of the corrosion."

Jan 1, 2000

By A. Kiziltas, D. J. Gardner, C. W. Mcllwraith, J. W. Bridge, M. L. Peterson

"Dynamic mechanical thermal analysis (DMTA) tests were conducted on high-oil content, paraffin-based wax used in wax-coated granular composites. These composites make up the surface of synthetic Thoroughbred horse racetracks used in North America. The modulus and damping response from the DMTA tests were correlated with the dynamic triaxial shear strength response of the bulk track material taken at two different operational temperatures and at four strain rates. The purpose of these tests is to understand the mechanisms of shear strengthening of the bulk track material as the wax is heated through the first crystalline solid to liquid nominal transition temperature. Previous work using differential scanning calorimetry confirmed that under common operational surface temperatures, the wax coatings undergo distinct thermal transitions. The resulting increase in triaxial shear strength values affects the consistency of the racetrack which, in turn, can potentially affect Thoroughbred racing performance and safety of the track surface.IntroductionSynthetic granular composite materials are being used in nine Thoroughbred horse racetracks in the United States as well as in other tracks around the world. In one case, their use was mandated by the state of California in 2007 due to testimony that these tracks were significantly safer than traditional dirt tracks [1]. Several synthetic tracks have shown substantial reductions in injuries since switching to synthetics; one California track showed a 75% reduction in catastrophic horse injuries during the first year as compared to the previous year racing on a dirt track [2]. The composition of the tracks in the U.S. generally consist of silica sand (>70%), polymer fibers (<5%), and rubber particles (0-15%) all coated with a paraffin-based, high oil content wax [3, 4]. In a recent study of several synthetic racetracks, to include the track location in this study, the oil content ranged from 34 to over 44% by mass [5]."

Jan 1, 2011

By Suresh Sundarraj

A diffusion mass transport model for predicting the microsegregation in a solidifying and coarsening dendritic mushy region of a binary alloy is presented. Two versions of this model are tested; one based on expressing the solute concentration in terms of mole fraction and the other on expressing the solute concentration in terms of mass fraction. On comparing previous model data sets and conditions, used in the analysis of Aluminum-Copper systems, a number of inconsistencies emerge. These inconsistencies are resolved on identifying a single set of data and conditions which take account of compositional density changes, "non-linear" thermodynamics and dynamic coarsening. An additional investigation is carried out to study the effect of assumed cooling mechanisms.

Jan 1, 1992

By Xue Ping

Sm2Fe17 alloy is an important precursor for the preparation of Sm2Fe17Nx magnet, which possesses a higher Curie temperature, larger anisotropy field, better resistance to oxidation and thermal stability. In this paper, the wet chemical co-precipitation was developed for synthesis of the Sm-Fe alloy oxide precursor. Based on the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Sm(III)-Fe(II)-NH3-C2O4 2--H2O system at ambient temperature were deduced theoretically and the thermodynamic diagrams of lg[M2+]T (M=Sm, Fe) versus pH at different solution compositions were drawn. Then, the experiments were done to address the various effects on the wet chemical process, including solution pH value, reactant concentration, reaction temperature and aging time, etc. It is found that by precise control of the process, the Sm-Fe alloy oxide precursor was synthesized with fine crystallization and special size &size distribution.

Jan 1, 2008

By Nathan A. Tiner

Sulfuric acid anodizing process is extensively used in many industrial and consumer products to provide corrosion resistance to aluminum alloys. The anodic coatings produced consist of amorphous alhnum oxide with a pornus structure which is easily sealed and colored with dyes. The coatings may contain defects due to surface flaws, canposition and microstructure of the aluminum alloy, and/or due to the anodizing process conditions. This paper will describe the techniques used in anodizing process, various defects which may be produced in anodic coatings and the methods to control them.

Jan 1, 1992

By Matthias Schnitzler, Herbert Pfeifer, Ralf Bolling

"To transform metals high temperatures are usually needed. A fast and efficient heating can reduce the C02 emitted. The fastest way to heat metals is called direct flame impingement (DFI). The flame impinges upon the item being heated. For this method it is important to know the shape and length of the flame. Laser-induced fluorescence (LIF) technology allows measurements of a two-dimensional field without influencing the reaction or the flow. Commonly used is the measurement of OH-radicals, an indicator of the reaction zone.In the presented study measurements of a turbulent diffusion flame are shown. The position of the reaction zone and the influence of the distance between the item being heated and the burner are investigated. Conventional measurements and LIP-measurements are compared and the potential of DFI to increase the efficiency of heating metals is discussed.IntroductionDuring industrial heating processes a fast and efficient heating technology is required. Two important aspects are the NOx emission and the energy efficiency. The direct flame impingement (DFI) technology has the highest heat transfer rate possible with a gas/air flame. The turbulent high velocity flame jet impinges upon the item being is heated [ 1]. Due to the high heat transfer rate furnace and exhaust gas temperatures are lower. Therefore the energy efficiency is increased and the amount of NOx emitted is reduced.Hydroxyl- (OH-) radicals are an intermediate product that is generated during the combustion of hydrocarbons [2]. They are commonly considered as an indicator for the reaction zone and position of heat release. Figure 1 shows the hydroxyl-mole fraction in dependence of the distance along the gas flow. The figure clearly shows how fast the OH-concentration increases in the reaction zone. Figure 1 also shows that OH-radicals are present in the post combustion region, however in smaller concentration [3].The laser-induced fluorescence technology serves to measure the spatial distribution of OH-radicals in a two dimensional cross-section area of the flame. Therefore the flame dimensions and location can be determined with high spatial resolution without influencing the flow or the reaction [ 4,5]."

Jan 1, 2012

By Muhamad Firdaus

There is a growing interest in Magnetoelectric (ME) materials in view of both fundamental understanding and novel desirable applications. The application potential for multiferroic materials with the possibility of reversing the magnetization by applying an electric field (or vice versa) is quite promising especially in data storage application. The rare earth ortho-ferrites (REFeO3), such as NdFeO3, have been studied extensively in recent study in the context of discovery of magneto-electric (ME)/multiferroic nature materials. In this paper a potential high temperature recovery of rare earth elements in the form of REFeO3 from waste permanent magnets using direct oxidation in air was investigated. It was found that REFeO3 (NdFeO3) phase can be separated from the other oxide phases by thermal treatment of NdFeB magnet waste at 1100 °C in air atmosphere. The REFeO3 also found to have different physical characteristic (density) from the other layers and can be separated physically. This paper will include a proposed flowsheet to recover Nd as NdFeO3 through powder separation. The technique can be beneficial and favourable for RE recycling and recovery from waste permanent magnets.

By Takeshi Nagano

Copper pyrometallurgy in Japan has experienced quite fundamental changes in last fifteen years. The severe environmental restriction coupled with increase of energy costs accelerated the development work of the new continuous process in Mitsubishi Metal Corporation. After several years of pilot plant test work the commercial plant was put into operation at Naoshima Smelter in 1974, the design capacity of which was 4,000 tonnes of copper per month. Many modifications and improvements have been incorporated into the process and 7,200 tonnes per month of copper production was achieved in 1983, proving that continuous process was much more economical than conventional process. It is now possible to design and operate the continuous process in wide range of capacity. This paper will review the process and describe the progress of the process in these 10 years. 311

Jan 1, 1985

By Scott W. Jorgensen

Hydrogen storage research has a long history, with a recent surge of new materials and new concepts. Important progress has occurred in the area of solid phase materials for storage, tank materials and engineering, and new types of materials. More importantly, an understanding of these materials is beginning to allow prediction of hydrides with improved properties. The performance of these new hydrogen storage systems begins to approach that of physical containment methods. The next step is to directly target performance that will permit commercialization.

Jan 1, 2006

By Wayne Bell, Matthew Andriese, Shuqian Xie, Jiann-Yang Hwang, Zhiwei Peng

"Pyrolyzed carbons are generally known as good microwave absorbers and their dielectric properties still remain to be fully explored. In the present study the dielectric properties and dielectric polarization-relaxation phenomenon of a typical activated carbon was investigated. The experimental results indicate the complex permittivity is highly dependent on temperature and frequency. The decrease of permittivity with increasing temperature from room temperature to ~100 °C is probably ascribed to the release of the water vapor adsorbed on the surface of activated carbon, and the variations of permittivity with temperatures between 100 °C and 450 °C in the frequency range of 300 MHz to 3000 MHz are mainly attributed to the decreased relaxation time of dielectric polarization.IntroductionPyrolyzed carbons have been identified as excellent microwave absorbers owing to their high dielectric and electrical loss under microwave irradiations. Among them, activated carbon continues to attract more and more attention from researchers. Due to its special physical properties, the production, modification and regeneration of activated carbon with the assistance of microwave have been widely studied over the last few decades [1-6]. However, only few attempts have been applied to explore the dielectric properties of such materials due to the complexity and variability of their organic precursors and activation processes [7,8]. In order to shed a light on this problem, a typical sample, Norit® A Supra USP powdered activated carbon, was adopted to perform dielectric characterization, which may provide useful information for its wide application in the fields of purification, energy (hydrogen) storage and so on."

Jan 1, 2011

By Jianhua Xin, Min Chen, Lei Xu, Haohua Deng, Nan Wang

A mathematical model of converter slagging and steelmaking process by replacing part of lime with limestone is established. The rate equations of oxidation reactions and lime dissolution in converter under the limestone substitution proportion increasing from 25 to 50% can be obtained and the effects of limestone substitution proportion on the variations of the composition of hot metal, slag and converter gas during the steelmaking process are investigated. In the process of converter slagging and steelmaking by replacing part of lime with limestone, increasing the hot metal temperature and the lance height could be favor to increase the content of FeO in the slag and accelerate the limestone decomposition and dissolution. With the limestone substitution proportion increasing from 25 to 50%, the maximum of oxygen supply ratio increases from 10.7 to 19.7% and the temperature drop of converter bath is 8–60 °C.

Mar 1, 2018

By Junji Shibata

Through-hole copper plating is performed to make a multi-layer printed circuit board. The through hole plating is first carried out by Pd catalyst treatment, followed by copper non-electric plating. The amount of Pd catalyst used in one plant is about 0.25-2 m3/month (8 g/dm3 PdCl2 base) depending on the plant scale, and the cost of the catalyst reaches 17,000¬I35,000 US$/month. In this study, the flow and material balance of a Pd in Pd catalyst treatment process was investigated. About 60% of Pd catalyst adheres on the through-hole and other part of setup, while 25% is released into the washing liquor. Pd in the washing liquor should be collected by a suitable method like a pressure filtration using diatomite. The material balance of Pd in Pd catalyst treatment process and the recovery method of Pd from waste solution containing Pd catalyst was investigated.

Jan 1, 2003

By P. D. Nolan

Smelters operating under pollution control orders have become increasingly dependent upon the reliable operation of sulphuric acid plants and no factor affects the long term reliability of those plants more than efficient gas cleaning. The sources and characteristics of contaminants in smelter of fgases and the conventional approaches to removing these contaminants to accepted levels are discussed. New technology is described which offers advantages of lower capital cost, lower operating cost and reduced space requirements over the conventional approaches. This new technology has been developed by LAB s.a. and is licensed for metallurgical gas applications by Chemetics International Company.

Jan 1, 1983

By Leonid M. Lerner

High temperature aluminum Alloy 8009 is a rapidly solidified/powder metallurgy aluminum-iron-vanadium-silicon alloy. This alloy in combination with hard oxide aluminum film has unique engineering properties which may recommend its use in compressors and impellers for aerospace applications. Various anodizing processes (including Sanford Low Voltage DC+AC Process) for these task will be evaluated and normal chemical composition, physical properties, and macrostructures of 8XXX aluminum alloys will be presented.

Jan 1, 2006

By Liping Gu, Gordon A. Irons

"A 1/3 scale ""thin-slice"" model of an electric arc furnace was developed so that gas could be injected to simulate foaming gas evolution. The influence of arc jets, oxygen lancing and bottom bubbling was also simulated. Liquid velocities were measured by a white light particle image velocimetry system. Numerical simulations of some of these effects were made using commercial CFD packages. Comparisons with measured results show that considerable care is required to select the appropriate model and to interpret the computational results.INTRODUCTIONDuring recent years electric arc furnaces (EAF) have captured a significant share of steel production, partially due to increased productivity through the introduction of advanced technology such as oxygen injection, slag foaming and long-arc operation, process automation and post-combustion. However, systematic analysis of the process and these effects on heat transfer and fluid flow in the furnace is still in its infancy. Most investigationsl1 6l have been restricted to a specific application such as oxygen lancing or bottom stirring. In addition, it is very difficult to make comparisons between these computed results and experimental/industrial results. In this work a 1/3-scale ""thin-slice"" model of Dofasco's 190 ton EAF was built. The fluid flow in the bath due to the arc jets, bottom stirring, oxygen lancing and CO evolution was simulated. The velocity distributions in the bath were measured using Particle Image Velocimetry (PIV) System. In addition, numerical simulations of bottom stirring and CO evolution were carried out using two commercial CFD packages (Fluent and Phoenics). The objective of this work is to validate the mathematical models so that they can be applied to the full-scale furnaces."

Jan 1, 1999

By Bing Ji Yan, Cui Wang, Ya Peng Zhang, Chuan Hui Li, Hong Wei Guo, Jian Liang Zhang

There are a lot of research of the chlorine element’s influence on blast furnace, and mainly pay close attention to the harm to gas pipes and equipment. There are three kinds of chloride in the blast furnace gas, including HCl, NH4Cl, and NaCl (or KCl, ZnCl, etc.). This paper mainly analyzes all kinds of phenomenon of the chlorine element overflowing blast furnaces in Jinan Steel, and puts forward some different viewpoints, which are that the chloride overflowing out of blast furnace in the types of HCl, NH4Cl, or NaCl (KCl) not only has much to do with raw materials of chlorine load level, at the same time with the blast furnace burden distribution. On this basis, comes up with countermeasures for the different situation, such as adjusting the burden distribution matrix to guarantee the central gas flow smooth and changing the kind of raw materials to reduce the chlorine quantity, which will be helpful to prevent the harmful influence of chlorine element.

Mar 1, 2017

By Xueming Lv, Xuewei Lv, Jie Qiu, Lunwei Wang

Non-isothermal multiple scanning rate analysis method was used to analyse the solid-state reduction of nickel laterite by carbon. According to the TG curves, the activation energies were calculated and the most probable mechanism functions were determined by the Malek method. The results show that the process can be divided into three stages according to the reaction degree (a): 0–40%, 40–70%, 70–100%, respectively. In the stage of 0 a 0.40, the most probable mechanism function fits the chemical reaction order function. In the stage of 0.40 a 0.70 and 0.70 a 1.0, the process may not be exactly described by one mechanism function.

Mar 1, 2017

By Shusen Cheng, Dongdong Zhou

The high temperature distribution in ironmaking and steelmaking industry is very important to control the smelting process. Although equipment is available to measure the temperature in the smelting process, in general it could just measure one certain point or only at discrete times. The real time temperature distribution in ironmaking and steelmaking is important because it could reflect reaction information and help to control the operation parameters. In this paper, a new method to detect the temperature distribution in ironmaking and steelmaking through the application of digital imaging system based on the color CCD was studied. In addition, the two-color method and partial least square method were used in the calculation model to improve the accuracy. The results agreed well with the measured temperature.

Mar 1, 2017

By R. E. Sundell, S. M. Correa

"A mathematical model is developed for the fluid flow in tungsten-inert gas weld pools. The fluid is taken to be incompressible, viscous, electrically conducting, and confined within a pool of specified shape. The flow is driven by surface-tension gradient (thermocapillary), electromagnetic, and buoyancy forces generally in this order of importance. Analysis indicates that the electromagnetic field may be calculated a priori and so decoupled from the nonlinear fluid mechanics and heat-transfer problem. The resulting set of equations is solved numerically by a line relaxation process. Computational errors caused by truncation in finite-difference schemes and by inadequate grid distributions are considered. The model is used to study several cases of differing heat and current input to the pool with and without surfactant-induced thermocapillary forces. The principal conclusions are that the thermocapillary flow, when present, is dominant with surface velocities on the order of 1 m/s. The heat transfer, as deduced from isotherms within the pool, is crucially dependent on the flow. Also, flow velocities and weld-pool surface temperatures were measuredand agree well with the model.2. IntroductionThe requirements of improved control and of automation in the TIG (tungsten-inert gas) welding process have led to the development of mathematical models for the heat transfer to the workpiece. It is now widely recognized that the fluid flow in weld pools sufficiently distorts the conduction heat transfer pattern to warrant inclusion in a process model. The experiments of Woods and Milner (1), among others, demonstrated that TIG weld pools could be driven by the electromagnetic J x B body forces present, J being the current distribution and B the induced magnetic field. Atthey (2) calculated that in typical pools the buoyancy force was about an order of magnitude less important - despite the large temperature gradients present - and neglected it in a computational study of the magnetohydrodynamic (MHD) flow. This work also reviewed many earlier studies of MHD flow caused by a source of current at a fluid surface, including analytical studies by Shercliffe (3), Sozou (4), and Sozou and Pickering (5), and a numerical study by Andrews and Craine (6). These works establish the importance of the electromagnetic force in the weld-pool flow."

Jan 1, 1986

By Saskia Duyvesteyn

For many applications in hydrometallurgy and water treatment it would be advantageous to use ion-exchange resins in stirred reactors. However, attrition of the resin may lead to significant losses of both resin and metal values and prevent water quality goals from being reached. We have studied the recovery of fine resin particles by froth flotation, using the model copper - Dow XFS4195 chelating resin system. As the functional group on the resin is a bis-picolylamine, the resin should be amenable to flotation by anionic collectors, such as sodium dodecylsulfate and sodium dodecylsulfonate. The kinetics of copper loading from dilute aqueous solutions in an agitated vessel were studied as a function of copper concentration, pH and resin bead size. The flotation of unloaded resin was investigated for different types of collector, collector concentration, conditioning time, and resin bead size. Potential applications are discussed.

Jan 1, 1995