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By Li Xi

This paper describes how a back-propagation neural network is built for predicting the properties of engineering materials from their other properties, compositions or processes. A predicted result of the impact toughness of a 12Cr-2Ni-1.5Mo stainless steel from its tempering temperature is presented. Furthermore, the combination of this neural network for prediction is able to supplement the unpredictability of the expert system outside its domain of expertise. An integrated system may perform more intelligently and solve more complex problems as well as human expert, in some case even better.

Jan 1, 1992

By Zhang Chuanfu, Li Shixiong

"In the electrolysis electrodeposition or electroplating of aqueous solution of copper, lead, zinc, nickel, manganese etc, with the increase in cathodic over potential the reducing rate of metal and the cathodic current efficiency increases and the deposit becomes more compact and smooth. According to this principle, a method and equipment of the auto-control of electrolyte quality is invented. The industrial application shows that this method turns the experienced operation into auto-control. The quality and quantity of metal is improved greatly and the consumption of electric energy is reduced.In the electrolysis, electrodeposition or electroplating of aqueous solution of copper, lead, zinc, nickel, manganese etc, usually organic additives are added according to the state of cathodic deposit according to experience. This traditional and experienced operation, often lead to that the quality of additive is not optimum which affects the quality and quantity of metal and increases the consumption of electric energy. To counter the controlling problem of the quantity of additive, the authors have invented a corresponding equipment of the auto-control of electrolyte quality [1], it has found application in industrial practice."

Jan 1, 2000

By G. Cifuentes

The kinetics of the electrolytic oxidation of cyanide to cyanate on PbO2-coated stainless steel anodes have been studied by both experimental and theoretical means. The anodes were based on 316 steel and performed in a satisfactory fashion. The pH of the studied KCN solutions exhibited a constant value about 11. Values for all the kinetic parameters have been determined and a mechanism for the studied reaction is proposed.

Jan 1, 1999

By Jinfu Xu, Youqing Cao, Yuting Lv, Hang You, Peng Jiang

"In present work, we reported the fabrication of composites consisted of M42 powder metallurgy high speed steel and 45 steel at one step via spark plasma sintering (SPS) technology. The interface microstructure, compositions and microhardness with the interface forming mechanism were investigated. The results show that the morphology and microhardness within the M42/45 steel interfaces exhibit a gradient distribution. The interfaces possessed a transition layer up to 10.2 ?m with few distortions and microcracks. The formation of M42/45 steel interfaces were driven by both fusion and diffusion processes. The former one was primary at the early sintering process, while the later one becomes dominant over the followed sintering process.IntroductionPowder high-speed steels have been widely used in cutting tools, cold-hot tools and dies, as well as in cut materials and structure parts with wear resistance and high-temperature resistance, due to its high hardness, good wear resistance, desirable cutting toughness and favorable hot hardness [1-2]. For materials of some parts in practical production, not only the favorable toughness is required to resist the impact action, but also the high hardness and exceptional wear resistance are demanded. According to the functional requirements and working conditions, bimetal composite materials are prepared in a certain mode, proportion and distribution, by designing two metals with different chemical and physical properties [3-6]. Considering the composites exhibit different properties in different positions of the parts with a combination of the advantages of two metals, they can obtain enhanced properties that the single one can not achieve."

Jan 1, 2012

By B. J. Jody

Each year, about 11 million tons of metals (ferrous and nonferrous) are recovered in the U.S. from about 10 million discarded automobiles. The recovered metals account for about 75% of the total weight of the discarded vehicles. The balance of the material or shredder residue, which amounts to about 3 million tons annually, is currently landfilled. The residue contains a diversity of potentially recyclable materials, including polyurethane foams, iron oxides, and certain thermoplastics. This paper discusses a process under development at Argonne National Laboratory to separate and recover the recyclable materials from this waste stream. The process consists essentially of two- stages. First, a physical separation is used to recover the foams and the metal oxides, followed by a chemical process to extract certain thermoplastics. The status of the technology is discussed, and the process economics are reviewed.

Jan 1, 1994

By C. O. Bounds

The magnetic properties of (NdDy)15Fe78B6 sintered magnets have been evaluated using powder prepared by Inert gas atomization. The atomized powder had a particle size distribution from 1 to approximate 1000 microns. The as atomized powders have been sieved into, coarse, intermediate, and fine fractions; magnetic properties were evaluated for the as produced powder and each fraction. A B, of 11.7 kG, a Hci of 11.0 kOe and a BHmax of 32.5 MGOe was -obtained on a sintered magnet made from the as-atomized powder. The magnet made from coarse powder exhibited a slightly higher B, of 12.1 kG, while that from fine powder showed a decrease in B, to 11.2 kG. Hydrogen decrepitation has been utilized to study its effect on the magnetic properties. Finally, cast ingots with a definite columnar structure have also been used to compare the magnetic properties of magnets of the same nominal, composition but of different alloy preparation process. Hydrogen decrepitation does not appear to improve the magnetic properties of magnets made from thin cast ingots. However, it does show a significant improvement in the Hci of magnets made from the atomized powders. Possible causes for the differences in the magnetic properties on magnets made from each process have been discussed in the paper.

Jan 1, 1992

By John P. Hager

One possible approach for the recovery of mercury from acid plant blow-down sludge in smelters is the use of a vacuum retort reactor for the vaporization of the mercury with subsequent collection of metallic mercury in an attached condenser. An experimental study was undertaken to investigate the vaporization of mercury when present as a compound in the Hg-S-O and Hg-Se systems. A transpiration reactor was modified to operate under reduced pressure and with a continuous flow of inert sweep gas. A water-cooled cold finger was inserted into the exit end of the reactor to provide for the rapid quenching of the exit gases and the collection of the mercury. Rates of vaporization were measured at several temperatures for each compound and were generally found to be constant at a given temperature and reactor pressure. The results were used to determine the minimum operating temperature for 100% vaporization of the compound in 60 minutes. For Hg2SO4, HgSO4, and HgSO/2HgO the required temperatures. for a reactor pressure of 50 Torr. were determined to be 634°, 622°. and 603°C. respectively. For HgO, HgSe, and HgS the required temperatures were 557°. 451°. And 382°C. respectively. For HgS the rate of vaporization was also measured at a reactor pressure of 1 00 Torr. The rate of vaporization was found to be slower resulting in an increased vaporization temperature of 423°C. It was also determined that the mercury vapor present in the exit gas stream can back-react with the other gas species to a significant extent and can result in very little condensed metallic mercury. For the vaporization of both HgS and HgSe. the mercury vapor was found to have back-reacted to the extent that virtually none of the vaporized mercury was collected in metallic form. For the vaporization of Hg2S04? HgS04, and HgSO4*2HgO the amount of metallic mercury recovered varied from approximately 50% for HgS04*2HgO to approximately 10% for Hg2S04 and HgS04. Only for HgO was the recovered mercury in primarily elemental form. The application of the results to the operation of a vacuum retort and condenser system is discussed.

Jan 1, 2001

By Garrett May

We present a periodic technique for measuring the thermal conductivity of thin, disk-shaped samples. In samples of this type, temperature measurements must be made across the sample faces and are therefore subject to large error due to the interface resistance between the temperature sensor and the sample. The technique uses measurements of the amplitude and phase of the periodic temperature across both a reference sample and the unknown material at several different frequencies. Modeling of the heat flow in the sample allows the simultaneous determination of the thermal parameters of the sample as well as the interface resistance. The technique is demonstrated on nanocomposite samples less than 1.0 mm thick.

Jan 1, 2008

By Jafar Safarian, Merete Tangstad, Leiv Kolbeinsen

"Silicon and its binary alloys have several applications in metallurgical, chemical, photovoltaic and semiconductor industries. Silicon goes to its liquid state within its production, refining and when it is alloyed with other elements. Therefore, the characterization of silicon melts thermodynamics is important and useful. The liquidus and activities in several silicon binary systems have been recently calculated by the application of two liquidus constants, which were established using the experimentally determined liquidus data. In the present study, the thermodynamic properties of six silicon binary melts, which are simple eutectics, are calculated by analytical approaches. In this case, the changes in the partial and integral Gibbs free energies and enthalpies of mixing are calculated and compared with the experimental data in literature. The enthalpies are calculated by two methods and the calculation results are compared to the data from the literature. It is shown that thermodynamic properties of silicon binary melts can be accurately predicted without the use of complicated thermodynamic software.IntroductionSilicon and its alloys have several industrial applications. Silicon is used for making aluminium-silicon alloys to produce cast parts, mainly for automotive industry. Silicon in the form of ferro-silicon is used to deoxidize and alloy steel and cast iron. The photovoltaic (PV) industry has had a rapid growth in the recent years and silicon is the dominant material used for the fabrication of solar cells. Silicon is primarily produced through carbothermic reduction of quartz in electric arc furnaces and the produced metallurgical grade silicon (MG-Si) contains around 1 wt% impurities. It is further refined to produce solar grade silicon (SoG-Si) with above 99.9999 wt% Si to fulfil the chemical requirement for PV application. Since molten silicon is processed all along the metallurgical route, obtaining fundamental thermodynamics knowledge about silicon melts is valuable for the related industries."

Jan 1, 2012

By S. Eckert, G. Gerbeth, K. Timmel, B. Willers, T. Wondrak, N. Shevchenko, M. Röder

The quality of the produced steel in the continuous casting process is significantly governed by the melt flow in the mold. However, direct flow measurements in liquid metals are still rather scarce. In order to investigate these flow phenomena, three experimental facilities operating with low melting liquid metals were installed at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The melt flow in the models is measured by the Ultrasonic Doppler Velocimetry (UDV) or the Contactless Inductive Flow Tomography (CIFT), multi-phase flows can be visualized by X-ray imaging. The obtained measurement results are primarily used for validation of numerical models. In this paper we will investigate the fluid flow in the mold and the behavior of the surface of the liquid metal using flow measurements by UDV and surface profile measurement by a laser scanner, respectively. Strong fluctuations and deviations of the free surface were observed in case of a static magnetic field

Jan 1, 2016

By Cheng Pan, Qiugang Yuan, Xuewei Lv, Mei Liu, Enguang Guo

Land-based nickel resources include nickel sulfide and nickel laterite. With the consumption of high grade nickel sulfide, use of nickel laterite has received more and more attention. The mineralogy and sintering behavior of limonitic nickel laterite with high iron and low nickel and silica was studied to offer technical support for producing ferronickel through sintering–blast furnace route. The mineralogy results showed that the main phases in this kind of nickel laterite are goethite (FeO(OH)), gibbsite (Al(OH)3) and NiFe2O4. The TGA (Thermogravimetric Analysis) and DSC (Differential Scanning Calorimetry) revealed hydroxide minerals in addition to absorbed water. After the sintering experiments the chemical composition, phases present (XRD analysis) and physical properties of the sinter were studied. The content of FeO in the sinter increased with increasing basicity up to 1.3, and then decreased with further increase in basicity. The yield of sinter increased (from 73% to 80%) with increase in the basicity from 1.1 to 1.7, and then the yield decreased with the further increase in basicity. Mg(Ni)(Fe,Al)2O4 is the main phase in the sinter while MgCaSiO4 and Fe2SiO4 is the main binder phase when the basicity is 1.1~1.5, and MgCaSiO4, Fe2SiO4 and SFCA is the main binder phase when the basicity is 1.7~2.1.

Jan 1, 2014

By Kaixi Jiang, Lan Li, Bang Wei, Haibei Wang, Yaping Feng

"China is currently the world's largest copper producer. In the last five years, 950 kt/y of smelting capacity was commissioned. Currently, about 1200 kt/y smelting capacity is under construction and about 2000 kt/y smelting capacity is under feasibility study. Ausmelt/ISA smelting and flash smelting technologies were commonly adopted in China. After the double-flash-smelter was first adopted in 2004, three new double-flash-smelters are scheduled. Recently, two new copper smelting technologies were developed in China. One is an improved bath side-blown smelting process, and another is the SK.S bottom blowing process. Both technologies have been in practice for over three years and have achieved good technical performance. Approximately 500 kt/y new smelting capacity in China and India will adopt these technologies. Both technologies have the advantages of low investment cost, low energy consumption and high flexibility for complex raw materials. This paper reviews ""green"" copper smelting projects in China and introduces the practices of the two new Chinese smelting technologies.IntroductionPresently, China is the largest copper producer in the world. As far as the smelting of copper is concerned, there are many smelting processes applied in industrial production, such as flash smelting, Noranda smelting, Ausmelt smelting, Isa smelting, the Mitsubishi process, Vanukov smelting, silver copper-smelting, SKS smelting, both side-blown smelting, traditional blast furnace smelting, electric furnace smelting, reverberatery smelting and so on . Except the last three traditional processes that are eliminated because of their failure to meet the requirements for environmental protection, all of the other above-mentioned methods are advanced smelting processes adopted nowadays."

Jan 1, 2012

A strategy is presented for a relatively. "low-tech" means for decontamination of streams . containing .low concentrations of toxic metals. Metal ion solutions were . circulate through fluidized beds of activated carbon which support bio-films ?of bacteria .that naturally excrete exopolysaccharides. The attached 'biomass is shown to significantly enhance nickel, cadmium and silver extraction from dilute solutions (5- l00mg/l). By heat treating (at 300º C) the metal/biomass/carbon particles, bio-sorbed silver was subsequently fixed to the carbon surface. This approach to metal decontamination may therefore also provide a route for dispersing and fixing catalytic metal particles over an activated carbon surface.

Jan 1, 1991

By Ehsan Khajeh

In this study, the permeabilities of Al-15.5wt%Cu and Al-19.5wt%Cu have been determined by solving the full Navier-Stokes equations on 3D geometries of interdendritic channels obtained by X-ray microtomography (XMT). The samples for XMT were sectioned from different positions in directionally solidified cylinders in order to obtain a variety of microstructures for each composition. The flow has been solved using a 2nd-order accurate Finite Volume Method (FVM) approach. The effect of employing uniform or unstructured mesh on the calculated permeability has been studied. The Marching-cube triangulation method was necessary to extract accurate surfaces for unstructured volume meshing. Calculated values of permeability for this range of solid fractions show partial agreement with previous experiments. Observed deviations are attributed to the difficulties of experimental permeability measurements.

Jan 1, 2009

By Denise Corrêa de Oliveira

Common dry batteries use zinc as the negative electrode. Producers commonly use additives such as mercury to prevent corrosion and to increase the mechanical resistance of the zinc anode. Alkaline batteries also contain it, as an anti-corrosive agent. When mixed with the common municipal solid waste, heavy metals as zinc and mercury pollute soil and ground water supplies, moving to the food-chain and affecting human health. Due to these possible damages, this kind of waste must be properly disposed, or recycled. Thus, even in low amounts (ppm) in batteries, mercury has to be eliminated or, at least, its content should be reduced. This work presents the use of pyromettalurgical processes, to reduce mercury content and recover zinc. The tests involved batteries treatment at temperatures from 300° to 1000°C. Mercury is eliminated up to 650°C, and zinc is evaporated at higher temperature treatment. C

Jan 1, 2001

Steel Ladle in Bhilai Steel Plant, SAIL, India, passes through VAD & LF-RH route and this exposes refractory lining to a severe operating conditions. Ladles are lined with in-house manufactured MgO-C refractories. Lining life used to be 35 heats, out of which 18-20 heats were through VAD/LF-RH, hence, ladle availability had become a constraint. Laboratory studies were carried-out to optimize granulometry and composition. Granulometry was developed by adopting Andearssen packing model. A suitable plasiticiser was identified to eliminate inconsistency caused due to variation in resin quality and weather condition. It reduced variation in green bulk density from 6 to 1.3%. Abrasion and slag erosion studies were conducted, which shows that with increase of carbon, abrasion resistance decreases and corrosion resistance improves. Based on these studies, graphite in slag zone was increased from 10 to 12.5% and in metal zone it was reduced to 7.5%. Different process parameters of brick making were optimized to make MgO-C bricks of maximum bulk density with reduced coke porosity. Modified bricks have bulk density of 2.99-3.02 g/cc and coke porosity of 9.5-10.5%. Further, shape of the bricks were changed from side arch to mini keys and thickness was increased from 80 to 100 mm. Mini key bricks are pressed from sides, thus eliminating variation in thickness which is critical dimension for dry joints. These modifications improved average lining life of steel ladles to 64 heats, which includes 37-40 secondary heats. Maximum life obtained is 87 heats.

Jan 1, 2006

By L. H. Gevantman

A program for the compilation of evaluated physical and chemical numerical properties data is being pursued at the National Bureau of Standards within the Office of Standard Reference Data. This program is being sponsored by the Department of Energy and managed by the Battelle Office of Nuclear Waste Isolation in Columbus, Ohio. The intent is to assemble a reliable body of numerical properties data concerning candidate mineralogical materials in which high-level radioactive wastes are to be buried. The ready accessibility of the data to site designers and the credibility achieved through the evaluative process are designed to help assess and compare the feasibility of each candidate material for use as a disposal site. Both generic and site-specific data are to be assembled. To date, generic rock salt properties have been assembled and published by the NBS as NBS Monograph 167. Details of the effort to produce this book are discussed.

Jan 1, 1982

By Lev Levin, Sergei Lesokhin

"The formation of titanium carbide during hot filament assisted carburizing of NiTi alloy was investigated. Phase content and morphology of the diffusion zone were examined by X-ray diffraction, X-ray microanalysis, SEM, and Auger electron spectroscopy. The growth of stable and adherent TiC film was observed. A non-planarity of interphase boundary was noticed. The applicability of the chemical diffusion approach to the analysis of the experimentally observed interface instability is discussed. A criterion, taking into account the influence of growth stresses on the stability of the flat interface, is developed by means of linear perturbation analysis.Introduction.Equiatomic intermetallic NiTi belongs to a class of materials exhibiting the shape-memory effect. The unusual property of this compound promotes its application in many fields, from aerospace technologies to medicine. The relatively high ductility ofNiTi also permits its use as a matrix material in metal-ceramic composites. The objective of this work was to investigate the possible incorporation of a ceramic material (titanium carbide) into NiTi by gas carburizing.Free energy calculations indicate the potential to obtain TiC by carburizing Ni-Ti binary phases. The main obstacle to such a process is the high affinity of titanium to oxygen. At moderate temperatures the formation of TiC is preferable to titanium oxidation only if the partial pressure of oxygen is extremely low [1]. This problem was overcome in this work by the use of hot filament assisted gas carburizing. Due to chemical reactions occurring near the hot filament, the gas mixture, initially consisting of methane and molecular hydrogen, was enriched by atomic hydrogen [2], drastically decreasing the content of free oxygen in the carburizing atmosphere.The second part of this article concerns the theoretical analysis of reasons that lead to the development of the experimentally observed morphology of the diffusion zone. In particular, the influence of the growth stresses on the morphology of an interphase boundary is investigated."

Jan 1, 1996

By Liyuan Chai, Bing Peng, Ji Peng, Di Yu

"Electric arc furnace (EAF) stainless steel dust has been classified as a hazardous waste by various government regulatory agencies as it releases heavy metals to environment. The solidification of EAF dust is to stabilize the hazardous components to the amorphous silica-alumina-based clays. The process of solidification is investigated and the softening temperatures of dust and additive clay mixtures are measured for economical thermal treatment. The results indicate that the mixture of dust and local clay with the ratio of 1:1 has the lowest softening temperature 1100 °C and it could pass the toxicity characteristics leaching procedure (TCLP) test for the environmental regulatory limits after thermally treated at softening temperature for 15 min. Major phases of thermal solidification product clinker are CaAl2Si2O8, (Fe, Cr)2O3, (Fe, Mg)(Cr, Al)2O4 and Al6Si2O13.IntroductionThe yield of stainless steels in China arrived to 10 million tons in 2006 and more than 0.2 million tons of stainless steel dust are produced annually. Approximately 1-2 wt.% of scrap charged to an electric arc furnace (EAF) enters the off-gases and then is converted into the dust and reported to the bag-house. The disposal or landfill of the dust becomes a serious environmental problem in China due to the increased production of stainless steels in recent years. The dust contains elements such as chromium (Cr), nickel (Ni), lead (Pb), zinc (Zn), cadmium (Cd) and their solubility in leaching media exceeds the environmental regulatory limits [1]. Even though easily feasible for low-grade MgO, it is not appropriate to stabilize the heavy metals from the heavily contaminated soils after the dust landfill [2]. Several dust treatment technologies have been developed and they can be divided into two types. One is to recover the metals from the dust [3, 4] and another is to stabilize hazardous components present in the dust [5, 6]. Recycling of the dust generated in EAF is a remediation option for cleaner production. Direct recycling of EAF stainless steel dust was developed to recover the metal value from the dust and protect the environment [7], but it was only suitable for the dust with high contents of Ni, Cr and Fe. As for the dust with low valuable metal content, thermal solidification is an appropriate choice for the dust treatment."

Jan 1, 2012

By Bowen Li

Copper vermiculite is a special nanomaterial with excellent antibacterial and antifungal performance. By means of ion exchange, copper vermiculite containing up to 5.8wt% copper was prepared. The chemical and mineralogical characterization of the material was investigated in this study based on the XRD, AAS, TEM and EDS analysis, as well as the calculation of crystalline parameters and crystal chemical formula. Cu2+ and Mg2+ have similar atom radius and same electrovalence. Correspondingly, the structure character of copper vermiculite is very close to that of standard Mg-vermiculite. Most of the CU21 may have occupied the interlayer cationic positions in the form of hydrate in vermiculite. However, some may have entered into octahedral coordinate positions. The values of au and bo of the copper vermiculite crystal cell have no obvious change compared to that of original vermiculite micropowder, but the Co value decreased slightly, which is desirable for the stabilization of the Cu2+ in copper vermiculite.

Jan 1, 2003