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By Akira Yazawa

In the field of pyrometallurgy, the equilibrium evaluation has recently become easy by use of thermodynamic software, but it is strongly desired to estimate the amounts of non-equilibrium minor components to simulate practical processes. However, simple physico-chemical technique can not be applied to evaluate practical non-equilibrium components for many reasons. As an engineering solution for postulated equilibrium system, the activity coefficient is modified and introduced as the simulation parameter referred to as the "adjustment coefficient." This modified thermodynamic calculations were adopted to various sulfide roasting processes where many solid phases are participating and the system is not necessarily in equilibrium. Successful simulation was realized by assigning suitable adjustment coefficients for minor components which form a pseudo solid solution in the calcine. Some examples from sulfation roasting and dearsenizing roasting were discussed. In the smelting system, the loss of copper in slag is caused by equilibrium and non- equilibrium reasons, that is, chemical dissolution and entrainment of copper in slag. The total copper content of slag was simulated by use of the adjustment coefficient for entrained copper.

Jan 1, 1998

By Tailoka F.

Various metallurgical residues from iron and steel making processes have been treated by chlorination in excess air with hydrogen chloride gas generated from the combustion of scrap polyvinyl chloride (PVC). The residues include dust from both the electric arc and blast &maces, hydrocyclone overflow, zinc - lead blast furnace slags and dust rich in zinc and copper from copper refining. Chlorination is achieved either directly by mixing the residues with scrap PVC or indirectly in a two furnace system. In the latter, scrap PVC is combusted between 523 and 573 K in a horizontal furnace and the resulting gases are then reacted with metallurgical residues in a vertical furnace at 1166 to 1329 K. Gas chromatography, thermogravimetric measurements, XRD and AAS have been utilised to study the reactions. The recovery of non ferrous metals is as high as 80 to 90 % and only a negligible amount of iron is carried over. The optimum temperature for combustion is between 518 and 573 K. Above 600 K, the evolution of HCI is so fast that sufficient chlorination is not achieved. Analysis showed that no dioxins were present in the gases, the residues or the chlorides.

Jan 1, 1997

By Shadia J. Ikhmayies

Zinc oxide (ZnO) flowered-fibrous micro/nanowebs were produced as thin films on glass substrates at 350 °C using the low cost spray pyrolysis (SP) method. The films were characterized using the XRD diffraction, scanning electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS). Hexagonal structure was confirmed from X-ray diffractogram, which showed preferential orientation along the (002) line. SEM images showed two dimensional flowered-fibrous micro/nanowebs, and EDS elemental analysis revealed the presence of chlorine in the films in addition to zinc and oxygen. The obtained morphology is important for optoelectronic device industry and solar cells, where it provides large surface area that helps light harvesting.

Mar 1, 2018

By S. N. Monteiro, E. B. Zanelato, J. Alexandre, M. T. Marvila, A. R. G. Azevedo, G. C. Xavier

One of the parameters used in the study of mortars is the adhesion resistance, which indicate show much the mortar adhered to the substrate. The usual study is done at 28 days, to worldwide standardization. Few researchers study the adhesion of mortars to ages other than 28 days. In this scenario, the adhesion strength tests of conventional mortar with a 1:1:6 mass scale (cement, and sand) at 7, 14, 28, 56, 91, 182 and 364 days were performed in order to understand the behavior of this material. The usual characterization tests of the mortars were carried out to correlate the values obtained with the adhesion results. The obtained results demonstrate that the mortar continues to gain resistance with the passage of time. For the trait studied the gain was considerable, indicating that over time the cement continues to hydrate, reacting and contributing to the strength of the material.

Mar 1, 2018

By Chaoying Ni, Dimitry Sediako, Prashant Karandikar, Sean Fudger

Neutron diffraction measurements were performed on steel encapsulated metal matrix composites (MMCs) in order to quantify bulk residual stresses. A coefficient of thermal expansion (CTE) mismatch induced residual compressive stress method is utilized as a means of improving the ductility of the MMCs and overall efficiency of several macro hybridized materials systems. Systems consisting of an A36, 304 stainless steel, or Nitronic® 50 stainless steel shell filled with an Al-SiC or Al-Al2O3 metal matrix composite are evaluated in this work. Upon cooling from processing temperatures residual strains are generated due to a CTE mismatch between each of the phases: steel, aluminum, and reinforcement. The analysis shows variation in the measured strain and stress results due to outer steel thickness, difference in CTE between materials, and relative position within the composite.

Mar 1, 2017

By Jun Li, Lingling Zhang, Daqiang Cang, Guizhou Zhao

Pilot trial of direct modification of molten blast furnace slag and production of high acidity coefficient slag wool fibers were investigated nearby a blast furnace. Molten blast furnace slag discharged from blast furnace and then directly flow into specialized modification furnace and quartz was simultaneously added into the molten slag as modification agent. The modified molten slag was electric heated to 1500–1550 °C and then the melt was produced into slag wool fibers through high-speed centrifugation method. Melt with acidity coefficient of 1.2, 1.4, 1.6 and 1.8 were investigated and fibers with corresponding acidity coefficient were produced. Slag wool fibers with shot content of 5.5, 5.8, 6.2, 6.8% and average diameter of 4.5, 4.9, 5.6, 6.4 lm for four samples were successfully produced, respectively. Total energy consumption and production costs decreased by 50–70% compared to traditional cupola furnace method. This method provides an energy-saving and emission-reduction technology for the direct utilization of molten blast furnace slag.

Mar 1, 2018

By James Douglas

A century ago the AIME meeting of 1899 was held at the Palace Hotel in San Francisco California in September. For his presidential address, James Douglas presented this paper which is reprinted in full with the kind permission of the AIME. It presents an interesting comparison relating to events and circumstances in the metallurgical industries at the close of last century. Being on the eve of a new century ourselves, the Editors of this volume of the COPPER 99-COBRE 99 Proceedings considered this paper would be of general interest, hence it is included here. Douglas believed in effective interchange of technical experiences and ideas. He considered the extreme secrecy surrounding the copper works at Swansea, Wales, the world center of copper only years before the time his paper was delivered, as one key reason for its decline, (and eventual closure of all copper plants there). In his paper, the pace of developments in various sectors such as transportation (railroads, the dominant means of I transportation at the time), the iron and steel and copper industries were examined, in much the same way as one might do but on the high technology of today. James Douglas was born in Quebec City, Quebec, Canada and spent his early life there. Forced to move to the United States for family and financial reasons, he went on to become a pioneer in the new Arizona copper industry, and with luck and good judgement with his interest in the new mining properties he also became very wealthy. Douglas was an accomplished mining and metallurgical engineer. He was the first President of Phelps Dodge and helped transform the small trading company of Anson Phelps and William Dodge into a mining giant.

Jan 1, 1999

By Ze-Qiang Xie, Bai-hui Wang, Feng Chen, Ling-zhi Yang, Yu-feng Guo

In this paper, based on the big data in steelmaking process, equation about the relationship between steel composition (especially the oxygen content) and the element yield is established by using mathematical analysis method to analyze the factors influencing yield. Meanwhile, combining the alloy yield data-base that were established based on self-learning of historical data and computer technology in steelmaking process, a method of yield prediction of alloy elements is studied. To provide support for this method, alloying elements yield prediction software is developed to realize the rapid and intuitive site operation guidance, and to realize the precise control of dosage of alloy material.

Mar 1, 2017

By Dong Hoon Han

The sulfation rates of magnesium oxide and calcium oxide (molar ratio 7:3) contained in calcined CMA ( calcium magnesium acetate) by SO2 were measured. The experiments were carried out in the temperature range 700 to 1100 °C and under the SO2 concentrations of 0.3 to I mol % (5 % 02). In the low-temperature range below 830 °C the reaction produced CaSO4.3MgSO4 and unreacted MgO, but no MgSO4 phase. The formation of CaSO4.3MgSO4 phase has a significant implication in that it allows the utilization of MgO for SO2 removal whereas the sulfation of MgO from conventional sources is so slow that it is of no practical interest. Thus, the calcined CMA can remove SO2 at lower temperatures than conventional SO2 absorbents and at a greater capacity. Above 950 °C only CaO reacts with SO2, but at a much greater rate than the calcined Ca(OH)2, which is one of the most reactive SO2 absorbents.

Jan 1, 1998

By Zvi Rivlin

Classical nucleation theory states that in first order phase transformations, such as liquid to solid transition, nucleation of the product phase starts with the formation of small, unstable clusters (embryos). When the thermodynamic barrier to nucleation is overcome, the embryos grow and attain a critical size, beyond which they are stable, i.e. they become nuclei. If nucle- ation does not occur, the parent, liquid phase remains in metastable equilibrium. At temperature lowers, undercooling increase and atomic mobility decreases. The viscosity change in the undercooled liquid may result in the formation of glassy state. As demonstrated in previous papers [I-21, in solidification involving surface nucleation of the product phase, as the case is in rapid quenching by melt-spinning, both nucleation temperature and nucleation time depend upon the number of atoms available at the isothermal surface in contact with the substrate. As a result of the thinness of the melt-spun ribbons, the embryo clusters that form at the freezing temperature may not be supplied by the amount of atoms necessary for their growth to critical nuclei sizes. In such extreme conditions, the liquid does not crystallize, it forms a metallic glass. A numerical simulation method is proposed for the reactions involved in embryo cluster formation and growth, at the atomic level. The simulation enables the caIcuIation of either the nucleation or the glass transition temperatures. Calculations made for the well-known glass forming CuZr and FeB systems afford prediction of the geometrical and thermodynamically conditions necessary for the formation of either crystalline or amorphous ribbons in melt-spun ribbons.

Jan 1, 1994

By Yue Yu, Hangyu Zhu, Jianli Li, Di Wang

Thestainlesssteelslagastheby-productofsteel-makingplantscontains 2–10 wt% Cr O , and the potential elution of hexavalent chromium impedes the 2 3 utilization as a secondary resource. The reduction of chromium oxide in steel- making slag containing Cr O by FeSi at 1550 °C was investigated in the labora- 2 3 tory. The experiments were performed in a carbon-tube furnace, and the samples collected during tests were analyzed using X Ray Fluorescence (XRF) and Scanning Electron Microscope (SEM) equipped Energy Dispersive Spectroscopy (EDS). The results show that the FeSi addition could efficiently enhance the reductionandrecoveryofchromium.WhentheamountofFeSirangedfrom2upto 9 wt%,therecoveryincreasedfrom65.60%to84.19%.Theoccurrenceofresidual chromium was metal particles, which dispersedly distributed in silicate phases owing to the size limitation. The sufficient FeSi could easily reduce chromium oxidesintometal,butthecriticalfactorofchromiumrecoveryistheprecipitationof suspending metal particles from the molten slag. Thus, some measures should be proposed in order to make sure that the suspending particles are adequate to aggregate into bigger ones. (cid:1) (cid:1) (cid:1) (cid:1)

Mar 1, 2018

By Tatsuzo Kitamura

The tank house of Tamano refinery, that started its operation in January, 1972, was constructed incorporating the application of Periodic Reverse Current (P.R.C.) from the outset of design works. In 1973, the production of electrolytic copper came up to 8,000 mtpm, a sharp increase ds compared with the designed capacity of 7,000 mtpm, and successful operation has been achieved up to the present. P.R.C. has been employed for the purpose of raising productivity level and reducing copper inventories. Since there were various problems in P.R.C. application to such a large sized cathode as 1 m x 1 m, special attentions were paid to the following items: -Development of a unique bus bar to make an electrolytic current to each electrode as uniform as possible. -Improvement of circulating method of electrolyte. -Application of high-performance equipment to realize a uniform spacing between anode and cathode. Owing to these creative technical developments mentioned above, technical level for operation up to 350 amp per sq m of cathode current density has been established. The quality of electrolytic copper, which was a matter of interest, has been proved to be as excellent as those of conventional electrolysis products through a long term supply to the field of SCR and Dip forming where high levels in quality are required.

Jan 1, 1976

By Susumu Imashuku

A pseudoternary phase diagram of the BaO?ZrO2?ScO1.5 system is established and the conductivities of the scandium-doped barium zirconate are measured in wet conditions. According to the phase diagram, the molar fraction of scandia in the barium zirconate phase that equilibrates with the cubic zirconia (ZrO2) and scandia (Sc2O3) phase is 0.03. On the composition line, where the molar fraction of barium oxide (BaO) is 0.50, the solubility of scandia into barium zirconate is 0.27 as a molar fraction of scandia. At around 500 °C, the conductivities of scandium-doped barium zirconate are estimated to be almost same as that of yttrium-doped barium zirconateThe activation energies for bulk proton conduction in scandium-doped barium zirconate (0.57 eV for BaZr0.90Sc0.10O3-d) are higher than that of yttrium-doped barium zirconate (0.44 eV for BaZr0.90Y0.10O3-d). In addition, the bulk conductivity of scandium-doped barium zirconate in this study is 10 times higher than the reported conductivities in the temperature range of 75 °C to 300 °C.

Jan 1, 2006

By Jan Petter Maehlen

Solid H-absorbing materials are in focus of ongoing R&D to offer viable solutions for the hydrogen storage and supply systems aimed on use of hydrogen as energy carrier for automotive transportation. Low operating pressures, combined with high gravimetric and volumetric efficiencies, together with fast kinetics of hydrogen release at ambient temperatures (providing conditions for a low energy loss due to decomposition), are the most important features of the ?ideal? H storage material. Hydrides of the light elements are the only possible candidates to build systems with an overall efficiency similar to those accommodating liquid or compressed (700 bar) hydrogen. One promising material from this point of view is aluminium trihydride, alane AlH3 with a gravimetric storage capacity of 10 wt.% H. This work was focused on studies of the crystal structure and thermal decomposition of alane by application of powder synchrotron X-Ray diffraction.

Jan 1, 2006

By Ragnhild E. Aune, Mark William Kennedy, Shahid Akhtar, Jon Arne Bakken

"To determine the heating rate of billets using ‘short coils’, an appropriate correction factor must be applied to the theoretical relationship. In 1945, Vaughan and Williamson published a semi-empirically modified Nagaoka coefficient applicable for moderate frequency induction heating processes (10 kHz). Recently it was demonstrated that the method of Vaughan and Williamson gives <10% error in the estimated power when heating aluminum billets at 50 Hz.In the present study, experiments have been conducted on aluminum billets in order to verify an empirical frequency corrected ‘short coil’ equation. Measurements of electrical conductivity (<± 0.5%), current (± 1%), heat (± 1-3%), and magnetic flux density (± 1-2%) have been performed. The results are compared with 1D analytical calculations, and 2D axial symmetric FEM modeling using COMSOL 4.2®. The frequency corrected equation has proven to provide accurate predictions of power (<4% error) within the frequency range 50 Hz to 500 kHz.IntroductionInduction heating is commonly applied to the re-heating of billets before forging or extrusion processes. The resistive heating produced by eddy currents in the solid or semi-solid work piece during this procedure, is driven by the time varying magnetic flux density in the air-gap between the work piece and the coil. The flux in the air-gap is created by the current flowing in the induction coil, i.e. the magneto-motive force. In Figure 1 it can be seen that the currents present in the work piece are concentrated in the outer ‘shell’, or the first electromagnetic penetration depth (dw), and flow in a direction which opposes the magnetic field produced by the induction coil."

Jan 1, 2012

By S. N. Monteiro, L. G. Pedroti, D. P. Santos, M. S. Peixoto, G. C. Xavier

The Baixada Campista is a region located in the municipality of Campos dos Goytacazes and is known as an important pole producing ceramic artifacts in Brazil. The clay used in this production is usually extracted from different layers of the region itself undergoing a pretreatment process. The objective of this work was to characterize the different soils (A, B and C), from different layers of the reservoir, in order to characterize the different physical and chemical characteristics (granulometry, determination of Atterberg limits, moisture and chemical analysis). To optimize, using the simplex methodology, properties such as mechanical strength, porosity and linear retraction. The results pointed to an optimum proportion of the clays studied so that the properties meet the Brazilian technical norms, being the proportion of 30% of soil A, 30% of soil B and 40% of soil C well.

Mar 1, 2018

By Wen-long Zhan, Zhe Ning, Jun-hong Zhang, Ji-hui Liu, Zhi-jun He, Qing-hai Pang

The influence of microwave irradiation and ultrasonic vibration on granularity of 0.074 mm pulverized coal was investigated in this research. It is indicated in the results that the granularity of coal decreased after microwave treatment, which led to the increased in specific area of pulverized coal in combustion reaction and consequently optimized the kinetic condition of combustion reaction. Higher ultrasonic power may lead to better performance of PC in combustion. The optimum condition for ultrasonic treatment is 10 min under 350 W microwave power.

Mar 1, 2017

By Chu Yong Cheng

Manganese is one of the main impurities in the recovery of base metals from their ores. This is especially true when laterite ores are processed using the pressure acid leach (PAL) process. The use of intermediate precipitation, solids/liquid separation and re-leach in the three Western Australian nickel laterite plants to separate nickel and cobalt from manganese and other impurities makes these processes complicated and costly in capital and operation. The research work carried out by the solvent extraction (SX) group at the A J Parker Cooperative Research Centre for Hydrometallurgy (CSIRO Minerals) has led to the development of direct solvent extraction processes to separate nickel and cobalt from manganese and other impurities. The simplicity of the process flowsheets and the expected savings in capital and operating costs are the major advantages of the new direct solvent extraction processes over the existing processes. By using a new synergistic organic system, Versatic 10 / dccyl-4-pyridinccarboxylatc ester, with a pilot plant leach solution from BHP¬Billiton (after iron precipitation), the metal values (Ni and Co) together with zinc and copper were separated from manganese and other major impurities (Mg, Ca and Cl) in the first SX circuit. The co-extracted manganese, magnesium and calcium were easily scrubbed out. The extraction and stripping kinetics of the metals with the new synergistic organic system were very fast and the synergistic system was found to be chemically stable. pH-extraction isotherms of metals with D2EHPA showed that the extraction order as a function of pH50 was Zn2+ > Ca2+ > Mn2+ > Cu2+ > Co2+> Ni2+> Mg2+. Semi-continuous test work with a cobalt pilot plant leach solution from Peko Rehabilitation Project Pty Ltd and a synthetic solution to simulate a concentrated laterite leach solution from BHP-Billiton showed that manganese, together with calcium, copper and zinc can be separated from nickel, cobalt and magnesium. This led to the development of another direct solvent extraction process to separate manganese and other impurities from nickel and cobalt and to recover nickel and cobalt from leach solutions. A project was initiated by HiTec Energy Ltd to recover manganese from waste laterite leach solutions using SX technology and to further purify it to produce high purity electrolytic manganese dioxide (EMD) for the high quality alkaline battery industry. Batch tests were conducted to select a suitable organic system for the extraction of manganese in terms of selectivity and extraction and stripping kinetics. A total of eight organic systems were tested using waste laterite processing solutions. A Versatie 10 / synergist system showed very promising results. By using the synergistic system, high manganese recovery would be obtained, fewer SX stages would be required and a higher A:O ratio could be used in extraction, resulting in a smaller organic inventory and lower capital costs. The risk of gypsum formation is also minimised with the synergistic system. Keywords: Solvent Extraction, Manganese, Laterite, Synergist

Jan 1, 2004

By Xiao Hong, Zhang Wenqiang, Gao Bing

The characteristics of top charging coke (coke 1) and stamp charging coke (coke2) were investigated. The weight loss ratios of two kinds of cokes with and without alkalis were measured after reacting with CO under the temperature of 2 900, 1000, 1100 and 1200 °C respectively. The microstructures of original cokes were observed by SEM. The experiment results show that, with no addition of alkali, the weight loss ratios of coke 1 and coke 2 were nearly the same under the temperature of 900 and 1000 °C. While the weight loss ratio of coke 2 was much larger than coke 1 under the temperature of 1200 °C. With alkali-rich, the weight loss ratio of the two cokes was almost the same at 1100–1200 °C.

Mar 1, 2017

By M. X. Huang, Y. Z. Li

The titanium diboride (TiB2)-reinforced steel composite, designed for automotive applications, exhibits a combination of high isotropic Young’s modulus and low density as compared to existing advanced high strength steels (AHSS). The steel-based composite is produced by in situ precipitation of TiB2 particles during eutectic solidification followed by hot rolling, and its microstructure displays a homogeneous distribution of both large primary TiB2 and small eutectic TiB2 particles in the ferrite matrix. Instead of interfacial debonding, particle cracking is the primary mode of damage, revealing very high interfacial strength. To investigate the intrinsic interfacial strength, a hybrid method combining both nanoindentation and finite element analysis (FEA) was used. A micron-sized sample containing a single crystal TiB2 attached to the ferrite matrix was fabricated by focused iron beam (FIB), and was compressed using nanoindentation with a flat indentation tip. By combining the compression and FEA results, the interfacial strength was therefore determined.

Mar 1, 2017