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By Xi Dai

The LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode materials for Li-ion battery were synthesized with Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) as Fe sources by high temperature solid-state reaction method. The Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) materials were produced by liquid co-precipitation method and crystal structure and morphology of cathode materials were characterized by X-ray diffraction and scanning electron microscopy. The composition contents and charge-discharge performances were measured by chemistry analysis and charge-discharge apparatus. The XRD patterns showed that LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode material samples were well-crystallized homogeneous olivine-type phase, with only tiny trivalent iron impurities according to chemistry analysis results. Charge-discharge test showed that cathode materials possessed excellent charge/discharge capacities, about 150mAh/g at 0.1C rate and more than 120mAh/g at 0.4C rate. The polarization of cathode in charge-discharge process can be restrained effectively, for the potential offset between oxidative peak and reductive peak of doped LiFePO4 material was only 0.079V, lower than pure LiFePO4 markedly.

Jan 1, 2006

By S. Raghavan

The thermodynamic activities of MgO in the solid solutions that can exist in the system NiO-Mg0-Zn0 are determined by measuring the EMF of the cell: O2 (g), Pt / MgO, MgF2 // MgF2 // x MgO + yNiO + (1-x-y)ZnO / Pt, O2 (g) / MgF2 in the temperature range 1190-1237 K. Equilibrium phases were prepared along the quasi- binary lines MgO/NiO = 0.1765,0.3333, 1.0,3.0 and 5.667 with the ZnO contents being 0.1, 0.2, 0.25, 0.35, 0.5, 0.75 and 0.9. The crystal structures of the phases were identified by X-ray diffraction. Results obtained so far show that a single phase MgO-rich cubic solid solution exists upto 0.2 ZnO content and for compositions above 0.25 ZnO, a second ZnO rich wurtzite phase forms in addition. Activity measurements show that for low MgO and ZnO contents, the MgO activities exhibit ideal to slight positive deviation from ideality and at higher MgO contents, a negative deviation is shown. Further studies are in progress.

Jan 1, 1993

By K. Koike, N. Masuko, Y. Takasaki

At the Zinc & Lead'95 symposium, one of the authors presented several modifications of Pb-Ag-Ca alloy anodes for the zinc electrowinning process, and also, the behavior of some organic additives in the electrolyte. In this study, the mechanical properties of the electrode materials composed by Pb-0.5 wt% Ag-(0~0.8) wt% Ca were studied by the tensile and Vickers hardness methods. Furthermore, experimental research on the influence of rolling and annealing treatments on the electrolytic behavior and mechanical properties of these alloys was carried out. The tensile strengths of the annealed Pb-0.5 wt% Ag-(0.1-0.8) wt% Ca alloys were the same or higher than those of the as-cast Pb-0.9 wt% Ag alloy. The anode potential using the as-cast Pb-0.5 wt% Ag-0.6 wt% Ca alloy decreased compared to the as-cast Pb-0.9 wt% Ag alloy. Moreover, the annealed Pb-0.5 wt% Ag - 0.6 wt% Ca anode after rolling showed a lower anode potential than the as-cast Pb-0.5 wt% Ag - 0.6 wt% Ca anode.

Jan 1, 2000

By R. E. Fanning

"IntroductionThe Aluminum industry is one of many materials industries which strive to make their material the preferred choice for large volume products. In some applications one material has a natural advantage over others, but more frequently several materials compete with one another, each providing one or more advantages and some trade-offs. Customers may design their product with several objectives such as minimum system cost, maximum customer appeal or maximum manufacturing flexibility, choosing materials which best combine cost and performance. In such markets it may become necessary for a material supplier to enhance the attractive features of the particular material to outweigh its disadvantages.It is difficult, if not impossible, to predict how various materials will evolve. Technological breakthrough, government regulations, material availability or sociological issues may redefine the balance between competing materials. In spite of some uncertainty regarding the competitive position of competing materials, there is little doubt that unrelenting pursuit of product quality improvement and cost reduction are essential to future viability of the aluminum industry. It is the intent of this paper to identify some areas where technological improvement would be beneficial. Thus this paper is a collection of briefly described problems that will hopefully stimulate the thoughts and research required for knowledge based solutions. Rolling ProcessA particular example is the beverage can industry where aluminum, steel, glass and plastics vie for a share of the m.arket. The high cost of aluminum relative to steel or glass requires minimizing the amount of metal per can. The high intrinsic value of aluminum has led to extensive recycling of cans although net metal cost is still higher than that of the competing materials. Intensive engineering of the beverage can led to improved design and better understanding of material requirements. These improvements permitted substantial reduction in sheet thickness over the past decade. The downward trend in metal thickness for beverage can sheet is shown in Figure 1."

Jan 1, 1988

By J. H. Meza

La Caridad copper smelter is located in the magnificent but rugged Sierra Madre Mountains. This project presents unusual challenges that require the utmost in detailed analysis and planning. The smelter, owned by Mexicana de Cobre, S.A. de C.V., has an annual production capacity of 225,000 metric tons of copper and 600,000 metric tons of sulfuric acid. It utilizes only the Flash Smelting process. This project will expand the annual production capacity to 270,000 metric tons of copper and 1,000,000 metric tons of sulfuric acid. Offgases from the Flash Furnace and the Teniente Converter will be sent to a mixing chamber, from which it will be led to two sulfuric acid plants. This project will then produce a high quality sulfuric acid.

Jan 1, 1995

By John W. Lund

The Geo-Heat Center has been investigating the utilization of waste silica from the Cerro Prieto geothermal field for several years. The main objectives of the research were to com-bine silica with various additives to (1) form bricks for low cost housing, and (2) to produce a suitable road surfacing material. The various additives that were tested included hydrated lime, portland cement, plastic fibers, asphalt cement and emulsified asphalt. The silica-cement combination produced the strongest bricks and had the best weather resistance, whereas, the silica-lime combination produced the bricks with the lowest thermal conductivity and specific gravity density. The addition of plastic fibers to the silica-lime mixture improved both strength and weather resistance. The combination of asphalt and silica is not suitable as a road surfacing material, however, silica-cement appears promising.

Jan 1, 2006

By Zhong g. Shui-ping

A new type Pb-Ag (0.8wt%)-Bi (0~5.0wt %) alloy used as anode in electrowinning of zinc from sulphuric acid electrolytes was prepared. The electrochemical properties of this ternary lead alloys have been tested and compared with those of Pb-Ag (0.8wt %) anodes used in industry. Results show the anodic overpotential decreases with the increasing of Bi content in the alloys. When the content of Bi was 1.0 wt% and 5.0 wt%, the anodic overpotential is about 40?50 mV and 60?80 mV lower than that of Pb-Ag (0.8wt %) alloy, respectively. The formation of oxide layers on the surface of these alloys was traced by LSV methods and the composition of the anodic oxide layers was characterized by XRD and SEM analysis. The surface layer on the two type anodes examined is mainly composed of a?PbO2 and ß?PbO2. But different structure of the surface layer was observed, Pb-Ag (0.8wt%)-Bi (1.0wt %) has a more fine-grained structure as compared to Pb-Ag (0.8wt %). But the film on Pb-Ag (0.8wt%)-Bi (3.0wt %) alloy is rather friable, cracked and not tightly attached to the anode.

Jan 1, 2008

By Edwin Adoyi Ali, Zainab Shehu Aliyu, Adele Dzikwi Garkida, Muhammad Dauda

Feldspar from Matari, Nigeria was analyzed using SEM, XRD and XRF techniques for microstructural analysis, mineral phase analysis and chemical composition analysis respectively. Qualitative and quantitative XRD analyses revealed the presence of microcline 59.6%, albite 34.7% and quartz 5.71%. The XRF results showed that the feldspar contains 67.32% SiO2, 17.54% Al2O3, 11.33% K2O, 2.75% Na2O, 0.12% CaO, 0.01% MgO, 0.02% MnO2, 0.10% Fe2O3, 0.00% Ti2O, etc and 0.14% LOI. SEM/EDX analysis shows the presence of microcline feldspar as the dominant phase, exhibiting lamellar twinning. The XRD has also revealed that potash has the highest peak, indicating its high concentration. The 0.10% Fe2O3 present is within the permissible level (0.1-0.3%) for glass making and also within the potash feldspar specifications (0.17%). The Matari feldspar is a microcline type, rich in potash, alumina and silica, enabling it meet the standard specifications for alumino-silicate glass.

Jan 1, 2015

By Ricardo Ponce

In recent years, ENAMI implemented modernisation plans at its two smelters in order to meet the government's environmental regulations introduced in the early 1990s. The modernisation plans defined the new SO2 and particulates emission targets, deadlines for compliance, and the revised treatment capacities of the smelters. At Las Ventanas smelter, the principal process change consisted of eliminating the reverberatory furnace. All the smelter feed is currently processed in a 4m diameter, 14m long Teniente Converter, using up to 34% oxygen enriched air. Dry concentrate is injected into the bath through tuyeres. A fuel oil burner compensates for any process heat deficiency. The Teniente Converter high copper content slag is cleaned in an electric furnace. This furnace is also used to melt internal reverts. This paper will discuss the successful operation of the slag cleaning electric furnace.

Jan 1, 1999

The paper concerns an unconventional, yet promising, use of waste magnesite dust and fines. In India a significant amount of this dust is generated from some of the integrated iron and steel industries, refractory and cement plants, during calcination of raw magnesite. However. it is possible to utilize this dust, which is normally a waste, conveniently and economically for the production of magnesium. chemicals. A bench scale study was carried out to determine the rate of formation of sulfated com¬pounds of Mg.Ca,and Fe, inter alla, present in the dust system containing MeO constituents (in which Me=Mg.Ca,Fe,Si,Al etc.) Effects of various process parameters, which affect the reaction rate as also the purity of the product ,were also studied. Some work carried out to develop the process flow charts involving the salient steps to produce magnesium chemicals commercially is reported in the paper .

Jan 1, 1992

By K. B. Shedd

Questions regarding possible adverse health effects from exposure to zeolites arose when the inhabitants of two villages in Turkey were found to have high incidences of mesothelioma, a disease generally identified with exposure to asbestos. No asbestos deposits are known in the area, but some fibrous zeolites have been found. Further investigations have resulted in conflicting opinions as to whether fibrous zeolites are related to the high incidence of mesothelioma in Turkey. The U.S. Department of the Interior, Bureau of Mines examined the habits of domestic zeolites by scanning and transmission electron microscopy. Only erionite and mordenite particles possessed acicular to fibrous habits. With the exception of a rarely occurring woolly erionite sample, the fibrous zeolites were not dimensionally equivalent to asbestos.

Jan 1, 1982

By K. Yarnaguchi

In the Mitsubishi Continuous Copper Converting Furnace, calcium femte slag is used. Due to its extremely high basicity, the improvement of corrosion resistance of the refractory lining is in need. In order to clarify the corrosion mechanism and to search for a new corrosion resistant material, first, the surface snuctures of bricks corroded in molten slags were observed by EPMA. Second, the dissolution behaviors of sintered MgO-based pellets containing various oxide additives were examined. It was found that the formation and the dissolution of magnesiofemte at the surface of the bricks play an important role in their corrosion and an addition of NiO, Mn02, or Ti02 to MgO is effective in stabilizing the magnesio-femte and improving the corrosion resistance of MgO.

Jan 1, 1994

By Sergio N. Monteiro

Fibers extracted from the ramie plant have been traditionally used in textile and are now being considered as polymeric composite reinforcement owing to their superior strength. Recently the mechanical behavior of ramie fiber reinforced polyester composites was investigated but no significant improvement was found. Therefore, the objective of this work was to carry out a similar investigation by changing the type of polymeric matrix. Specimens with up to 30% in volume of ramie fibers incorporated into epoxy were bend-tested until fracture. The results showed a moderate improvement with a tendency of decreasing stress for higher amounts of ramie fibers due to the weak interface developed with the epoxy matrix.

Jan 1, 2009

By Egil Krystad, Merete Tangstad, Kai Tang, Gabriella Trenell

"A new UMG-Si refining concept has been proposed in this paper. Liquid Si and another liquid metal phase (Me) were separated by the molten slag spontaneously based on their different physicochemical properties. Two metal/slag distribution reactions are able to occur in the system simultaneously. Experimental investigation on the B and P distribution equilibria among Si/slag/Me was carried out in the graphite resistance furnace under the inert atmosphere. The B and P doped silicon was in equilibrium with either the SiO2-CaO or SiO2-CaO-l0%CaF2 slags at 1600 and 1650°C, respectively. The pure Fe and Cu metals were used in order to ""capture"" B and P in the slag phases. B and P in samples were determined by the ICP-MS. B and P distribution coefficients for the Si/slag/Me equilibria were compared with the theoretical calculations. The possible kinetic barriers for the Si/slag/Me three-layer equilibria have been analyzed. The metal contaminations in the three-layer equilibria were also examined. The present study provides a new approach for the refining of MG-Si.IntroductionMost of the impurities in the metallurgical silicon (MG-Si) are rather ""dilute'', ranging from few to several thousand ppms. However, the target impurity levels for upgrade metallurgical silicon (UMG-Si) feedstock are often far below the level of ppm. In such extreme case, the conventional refining technologies face the great technical challenges. B removal by slagging has already been implemented industrially. Removal of Pis frequently carried out by the vacuum distillation. The separating treatments for B and P removals lead to increase refining cost, total CO2 emission and longer pay-back time of solar cell module.It is well known that the phosphate capacities of slags in equilibrium with liquid silicon are extremely lower. However, if we introduce another phase that possesses high ""phosphor capacity"" into the Si/slag system, one would expect to continuously remove P from Si through molten slag to the new ""phosphor capturer"". The so-called three-layer refming concept is thus proposed in the present study. Liquid Si and another liquid phase (Me) are separated by the molten slag spontaneously based on their different physicochemical properties. Two metal/slag distribution reactions are able to occur in the system simultaneously."

Jan 1, 2013

By Lucas Lopes da Costa, Sergio Neves Monteiro, Rômulo Leite Loiola

"Composites with DGEBA/TETA epoxy matrix reinforced with thinner and continuous bamboo fibers stripped from culms were mechanically characterized by tensile tests. Specimens with up to 30% in volume fraction of aligned fibers were tensile ruptured at room temperature. The results showed a steady increase in both the ultimate strength and the elastic modulus of the composites with the amount of incorporated bamboo fibers. The fractographic analysis by scanning electron microscopy showed evidence of moderate adhesion between the bamboo fiber and the epoxy matrix. This fiber/matrix adhesion by interaction mechanism apparently justifies the improved tensile properties of the composites.IntroductionIn recent years polymer composites reinforced with natural fibers, mainly those lignocellulosic obtained from plants, have been subject to extensive research works [1-5]. Environmental, economical, societal and technical advantages of these composites are motivating their substitution for similar polymer composites reinforced with synthetic fibers. In particular, R & D efforts have been conducted aiming to replace glass fibers composites that are comparatively more abrasive to equipments, non-recyclable, more expensive, heavier and toxic [6]. Among the many lignocellulosic fiber composites being investigated, those fabricated with bamboo stripped fibers, i.e., fibers longitudinally cut from the culm, still need information to support possible industrial applications. Several works, however, have been dedicated to bamboo stripped fibers as possible reinforcement of polymer composites [7-17]. These works reported mechanical properties that could markedly vary with the type of polymer matrix, the fiber disposition (if continuous, aligned, short-cut, mat interlayered, etc) and the test condition."

Jan 1, 2011

By Lucas Barbosa de Souza Martins, Felipe Perissé Duarte Lopes, Nathalia Carneiro Garcia Rosa, Lucas Lopes da Costa, Sergio Neves Monteiro, Rubén Jesus Sanchez Rodriguez

"The fibers extracted from the stem of the banana plant are relatively stronger and have been used as reinforcement of polymer matrix composites. In addition to quasi-static mechanical properties, there is a need to characterize the dynamic behavior of banana fiber composites subjected to thermal and mechanical constraints. In this work, the temperature variation of the dynamicmechanical parameters of polyester composites incorporated with up 30% in volume of banana fibers were investigated by DMA tests. The storage and loss moduli as well as the tangent delta were measured from 20 to 200°C in a TA Instrument operated with the flexural mode at 1 Hz. The results showed that the incorporation of banana fibers tends to increase the viscoelastic stiffness of the polyester matrix. It was also observed changes in the T g and the structure dumping capacity of the composites with increasing fraction of banana fibers.IntroductionNatural fibers with high amount of cellulose, also known as lignocellulosic fibers, have been used from primeval times by our civilization. In the last century, synthetic fibers such as nylon, carbon, aramid and glass fibers gained interest owing to superior strength and precise dimensional control. Natural fibers were then replaced by synthetics in many fields such as textiles and appliances. In the past decades, however, environmental issues drawn, once again, the attention to lignocellulosic fibers as possible substitute for intensive energy-consuming and long term polluting synthetics, specially the glass fiber [1]. In particular, research works have disclosed the potential advantages associated with the use of lignocellulosic fibers as the reinforcing phase in polymer composites [2-7]. Among the advantages it is worth mentioning the renewability, recyclability, biodegradability and the fact that natural fibers are neutral with respect to C02 emissions responsible for global warming. Moreover, as compared to synthetics, lignocellulosic fibers present lower density and cost as well as reduced wear caused to the processing equipment. On the other hand, in terms of composite reinforcement, hydrophilic lignocellulosic fibers present drawbacks such as weak adhesion to hydrophobic polymeric matrices in addition to dimensional limitations and non-uniform properties."

Jan 1, 2011

By Jiling Wang, Xuefeng Liu, Haojian Duan, Lifeng Zhang, Ying Ren, Wen Yang

"In order to study the influence of MgO-C refractory on steel cleanliness and inclusions during steelmaking process, and to understand the reaction mechanism deeply, laboratory deoxidation and equilibrium experiments were respectively performed in MgO crucibles at 1873K. In the former experiment, after Al addition, steel samples were taken at different holding time. In the latter experiment, different slag components and different contents of carbon and aluminum in steel were considered respectively. The inclusion characteristics of each experiment were analyzed. The results showed that with the increasing of holding time after deoxidation by Al, MgO existed in the small inclusions firstly, and then in the large ones such as the clusters. The MgO content in the inclusions increased with the increasing of holding time, indicating that the MgO in crucible could be individually reduced by the aluminum in the molten steel. The reaction could occur within nine minutes.IntroductionNon-metallic inclusions would have positive or negative effect on steel quality depend on the quantity, size and composition of inclusions. Large inclusions are always detrimental. From the point of view of inclusion property, plastic inclusions are required by steel cord, while hard inclusions are preferred by pipeline steel. One of the most important ways to increase the steel quality is reducing the inclusion size and controlling the inclusion composition in steel. Nowadays, MgO based refractory is used as ladle glaze material with more and more frequency, which results in different inclusion characteristics in molten steel, for example, the inevitable generation of MgO contained inclusions during ladle treatment of steel. In other words, the inclusions in this type ladle will influence on the steel cleanliness and the product property. Thus, keeping an eye on the inclusion formation behavior in the steel with MgO-C ladle glaze is important for the steel industry. There have been a few studies in this regard. Li et al[l] studied the reactions between MgO-C refractory, molten slag and metal using a high temperature X-ray radiographic apparatus. They found that the local corrosion was regarded as due to the cyclic dissolution of MgO and graphite in the refractory into slag and metal phase. The gas bubbles formed according to the reaction of (FeO)+C(s)=Fe(l)+CO(g) greatly influenced the corrosion. On an industrial scale, Du[2] found that ladle glaze is a major source of inclusions in the ladle. An experimental study has been performed by Lehmann in order to estimate the importance of the reaction between a MgO-based tundish refractory and an Al-killed steel[3]."

Jan 1, 2014

By Edward Peters

Scandium (Sc) has unique properties and is one of the more valuable elements in the periodic table. Scandium can be used in solid oxide fuel cells and to produce high strength aluminium alloys of value, for example, in the aerospace industry. Scandium is often grouped together with the rare earth elements (REE). Amongst others, scandium can be found in bauxite residues, so called red mud. It is possible to extract and enrich scandium from red mud by leaching and solvent extraction. Scandium can then be recovered from the pregnant strip liquor by crystallization. The strip liquor will however still contain certain impurity elements. In the present work, a method for obtaining a pure scandium solid phase by direct crystallization from the strip liquor is evaluated. It was found that Fe and Ti co-precipitate with Sc under the conditions employed.

By Yurniko Nakamura

Hydriding properties and crystal structure of a Ti-V- Mn solid solution alloy have been studied by P-C isotherm measurements and neutron and X-ray powder diffraction. The absorption P-C isotherm at 298K shows two plateau regions at 0.01MPa and 1MPa. The X-ray diffraction data have demonstrated that three phases with a BCC, a pseudo-cubic FCC and an FCC structure form subsequently with increase of the hydrogen content. Crystal structure of the latter two phases has been determined by Rietveld refinement of the neutron diffraction data. The FCC phase is the di-hydride of CaF2 type with hydrogen occupation in the T sites. The pseudo-cubic FCC phase is the mono-hydride of NaCl-type with hydrogen occupation in the 0 sites, which has not been reported so far. The lattice constants of the mono-hydride (Ti1.0V1.1Mn0.9)H_2.7 are a'=0.407 nm for two axes and c'=0.390 nm for the third axis. The a'axis is shorter by 4% than the c'axis. This pseudo-cubic FCC lattice is formed by contraction of 5% of the a axis and expansion of about 30% of the c axis from the original BCC lattice.

Jan 1, 2002

By Sudhir C. Dhara

An attempt has been made on the concentration of Platinum Group Metals (PGM) from the converter matte material by microbial .leaching. Biological oxidation of base metal sulfides such as iron, copper, nickel and free sulfur present in the matte material using Thiobacillus ferrooxidans is an alternative method to concentrate the PGM-and gold. The method which produces a platinum group metals concentrate is comparable to chemical processes and electrochemical process.

Jan 1, 1995