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By A. R. G. Azevedo, G. C. Xavier

"This work has for objective to identify the soil of the neighborhood Codin located in a lacking area of the urban nucleus of the district of Campos dos Goytacazes - RJ, after the identification the best line was determined for the production of soil-cement blocks. In this area it happens habitational deficit and precarious constructions are also verified. The use of soil cement blocks is considered a cheaper constructive method than the conventional (ceramic block or of concrete), because one of the components of the raw material is abundant (the soil) and the constructions can be erect with certain easiness for collective effort regime. Samples of soil of this area were collected for they be characterized with relationship to the physical and chemical characteristics, with I aid of GPS the community's location it was registered. Identified the soil type, the work began the study of lines they to make possible your use in an economical and safe way. For that were made drained blocks in the format 19,5x10x5 cm, with lines containing the addition of 5% and 10% of cement in volume, and as parameter of quality the absorption of water and the resistance to the compression were measured, following the Norms of ABNT.IntroductionWe know that the use of the soil by the humanity come from the antiquity. And ifs confirmed by the archaeology places of the old civilizations of the word. The most remote constructions date from 10.000 years old in Jericoh, in the Jordan River Valley. This work became more intensive at 3.000 B.C. (Before Christ), by people who lived in those valleys with mood areas, a lot of clay and washed by the rivers.Almost all the sectors of engineering of soils choose the stability to use the local soil. Although, artificially treated, offers more economical advantages.The stability of a soil consist of endow it of the condition to resist the deformations and ruptures during the period that it is being used, because these characteristics are necessary in any construction.The application of the natural soil only is possible in places that they are of good quality and attend to the requirements of engineering to the type of previewed application. The granulemeter correction and the chemical stability include cases of inappropriate soils areas, turning the soil able to be used as construction material. Among the stability agents, usually added to the soil for stability ends, the cement is indicated."

Jan 1, 2013

By Katsunori Okaya, Gjergj Dodbiba, Hiroyuki Ono, Toyohisa Fujita, Seiji Matsuo

"In an attempt to raise the copper grade of Printed Circuit board (PCB) by removing other components, carbonization treatment was investigated. The crushed PCB without surface-mounted parts was carbonized under nitrogen atmosphere. After screening, the char was classified by size into oversized pieces, undersized pieces and powder. The copper foil and glass fiber pieces were liberated and collected in undersized fraction. The liberation of copper foil from the oversized pieces was also investigated. The copper foil was liberated easily from glass fiber by stamping treatment. Liberation rate of copper foil was high at high carbonized temperature. The experimental results indicated that 90% of oversized char was liberated and the copper foil recovery from PCB carbonized at 1073K was 110kg/t. The copper recovery from char powder by flotation was also investigated. 15% of the copper grade and 80 % of the copper recovery were obtained, whereas the removal rate of silicon was 55%.IntroductionWaste Electrical and Electronic Equipments (WEEEs) should be recycled because they have many kinds of valuable materials and most WEEEs include Printed Circuit Boards (PCBs). In Japan, about 30 km2 per year of Printed Circuit board (PCB) has been produced [1], PCBs are normally separated from WEEEs and picked up by hand and sold to non-ferrous metal market because PCBs include high grade of copper and other precious metal such as gold, silver and palladium [2]. However, PCB also has impurities such as silicon, aluminum and calcium which are slag materials in non-ferrous smelting process, and other harmful elements such as lead, bromine and antimony. Low grade PCBs are sold after removal of invaluable parts or sometimes land filled without any treatment"

Jan 1, 2011

By Roberto Javier Santiago

The diferent applications of the Calcium Carbide in the steel plants are described in this paper, trying to give advantages in their use.

Jan 1, 2006

By Michael Stelter

Lead alloys are a typical material for anodes in technical electrowinning processes. The life time of those anodes differs from 2 years to more than 5 years in tankhouse practice depending on the type of alloy, the mechanical damaging and last but not least the chemical corrosion in the electrolyte. Different types of alloys, such as PbSb, PbCa, PbAg, PbSnCa or PbAgCa have been developed and used in the past, their rate of corrosion being more or less a philosophic discussion. Comparable investigations on the corrosion behavior in dependence of the concentrations of alloying metals, the grain structure and the mechanical and thermal treatment during production have not been conducted before. In the last years the Institute for Nonferrous Metallurgy and Purest Materials of the TU Bergakademie Freiberg investigated the corrosion behavior of the typical lead alloys for metal electrowinning under comparable conditions. Correlations between different alloys, mechanical treatments like rolling or thermal treatment like annealing to the rate of corrosion were made, leading to the conclusion that grain structure and grain size are of eminent importance for the rate of corrosion in technical electrolytes. From these results new and optimized lead alloy anodes can be produced with an increase in life time of the factor 3 ? 5. The optimized lifetime in terms of corrosion stability can not protect from mechanical damaging in tankhouse practice, but with a careful practice the increase in lifetime can save a lot of money and problems.

Jan 1, 2006

By Bernhard J. Ralph

In refractory gold ores much of the gold occurs in sub-microscopic form in sulfide minerals, most commonly pyrite and arsenopyrite Bacterial leaching is being developed as a pretreatment for these minerals to aid the liberation of gold and a variety of extracting reagents. This paper reviews the nature of the principal micro-organisms involved, the effects of various physico-chemical factors on the rate and extent of extraction, and likely mechanisms involved.

Jan 1, 1989

By Johan Sundström

Anhydrous DyC13 was prepared by dehydration of DyCl3?6H20 in a fluidized bed using both batch- wise and continuous feeding. A gas mixture with varied composition of argon and HCl was used. The productivity was high, reaching values of 0.25 mol H20/m2-st during the reaction step 6- 1 and 0.062 mol H2O/m2.s during the reaction step 1-0. The product was free from hydrolytic compounds, such as DyOCI, if control of inlet gas composition versus temperature was achieved. From the results of various experiments, some relations between HCI-concentration and temperature in order to avoid hydrolysis have been deduced. The fluidization process efficiency decreases drastically after the dehydration has proceeded down to about 10 mol% of remaining water. Therefore, in a final treatment the last traces of water were removed by slowly purging gas through a packed bed. The water content could thereby be reduced to less than 1 mol%.

Jan 1, 1997

"The pyrometallurgical method of recycling car batteries suffers from a potential for air pollution violations, which prompts the desire for a viable hydrometallurgicaJ alternative. Several Processes have been proposed, including leach-electrowinning routes using HBF4 and/or HzSiF6 based electrolytes, along with anodes of PbO2 on inert substrates.A study has been carried out to evaluate the proposed systems, with the intention of demonstrating a six month life of an electrolyte-anode combination. The work, which focused on the use of HzSiF6, has indicated that there was no acceptable anode, and has lead to the development of a technique to produce smooth, glassy, adherent coatings on graphite, and to the development of an anode composed of a series of copper cored graphite rods.The paper will present results on leaching and electrowinning experiments, as well as the description of a flowsheet for a pilot plant that will be used to produce one tone per day of refined lead from spent battery paste."

Jan 1, 1997

By Michael Heximer, Dominic Verfielst, Timothy Moore

"Teck's Trail Operations recently installed new pressure filters in the cold stage purification step in the zinc leaching plant. Alloy 2205 duplex stainless steel was chosen as the material of construction as it was in use in the hot stage purification operation. Within a year of commissioning, an unacceptably high rate (greater than 1 mm/y) of corrosion was observed on the weld heat affected zone (HAZ). Laboratory and field tests were conducted to establish the conditions under which the corrosion was occurring. The tests isolated the aggressive conditions to a unique combination of materials present during the filter regeneration stage. Furthermore, the change of the duplex grain structure of the alloy during welding resulted in the HAZ being more susceptible to the corrosive environment. A new material of construction was recommended as a result of the investigation.IntroductionThe sulphide leaching plant uses four horizontal tank pressure leaf filters to remove solids precipitated in the cold stage electrolyte purification process. The current filters were installed in 2007, and replaced a bank of filter presses. The material of construction for the filters - alloy 2205 duplex stainless steel - was selected based on its successful use in similar service areas of the leaching plant. However, within the first year, unexpected and rapid corrosion of the filter tank material was observed. Although moderate general corrosion was noted throughout the filters, the attack was particularly aggressive in the areas where intense heat was applied during fabrication, observed at the HAZs caused by welding, and on the exposed edge grain of the duplex plates. On the inaugural annual inspection of the filters in the first year of operation, a corrosion penetration rate of 1.0 to 1.5 mm/y was observed at the HAZs. The parent plate of the pressure tank was a minimum of 6 mm, with a minimum allowable thickness of 3 mm under the ASME pressure tank design rules. Therefore, the projected useful life of the filters could then be roughly calculated to be two to three years. Urgent action was required to understand and correct this problem."

Jan 1, 2012

By Guo Jun

In this study, BaTiO3 ultrafine particles surface-modified with stearic acid were synthesized by the hydrothermal method in a system of BaCl2-TiCl4-NaOH. The effects of NaOH/TiCl4 molar ratio, Ba/Ti ratio and time on structure and morphology of BaTiO3 ultrafine particles were investigated experimentally. The formation mechanism of different crystalline BaTiO3 particles was discussed, and it is considered that in a hydrothermal system, the main factors determining BaTiO3 crystalline are H+ replacement of Ba2+ causing H+ deficiency and anatase growth units involving in crystal growth, which clogs the axial channel for Ba2+ transference. By means of increasing the alkalinity of system and barium content, H+ deficiency and involvement of anatase growth units in crystal growth could be effectively controlled. The results show that when molar ratio of NaOH to TiCl4 is 9 and ratio of Ba to Ti 1.5, and time 8 hours, high purity tetragonal BaTiO3 ultrafine particles with a narrow grain-size distribution and nonpolar surface are obtained at 240oC. The particles have excellent flowability, which is ascribed that the surface polarity of barium titanium powder modified with stearic acid is changed and the interaction between the particles is weakened.

Jan 1, 2006

By A. D. Neuman, C. C. Davis, M. R. Lopez, A. C. Martinez, T. A. Nothwang, S. L. Voit

"One of the thrust areas for the Global Nuclear Energy Partnership (GNEP) program is the development of actinide bearing fuels for transmutation in a fast reactor. Mixed Oxide (MOX) fuel has an extensive fast reactor irradiation history and thus is being considered for use as a baseline composition from which minor actinides (MA) can be incorporated for use as a transmutation fuel. This study involves characterization of precursor powders and pellets to be inserted into the Advanced Test Reactor in Idaho. These pellets will have three compositions: one standard MOX composition, (U80Pu20)O1.98, and two compositions of MA-MOX with oxygen to metal ratios (O/M) of (U75Pu20Am3Np2)O1.98 and (U75Pu20Am3Np2)O1.95. The precursor powders, which consisted of, highly enriched uranium oxide, HEUO2, depleted uranium oxide, DUO2, neptunium oxide, NpO2, americium oxide, AmO2, and plutonium oxide, PuO2, were characterized using a field emission gun scanning electron microscope (FEG-SEM) for particle morphology, size, and size distribution prior to pellet production.IntroductionThe Global Nuclear Energy Partnership (GNEP) was created in order for “fuel-cycle supplier” nations to provide assured supplies of nuclear fuel to “fuel-cycle customer” nations. The customer nations would utilize the fuel for electricity generation and subsequently return it to the supplier nation after it is spent. This spent fuel would then be reprocessed by the supplier nation in order to recycle the actinide constituents, mainly uranium and plutonium, in advanced nuclear power reactors, and thus reducing waste volumes [1, 2]. Nuclear materials would also be strictly controlled through the International Atomic Energy Agency. One of the thrust areas for the GNEP program is the development of these actinide bearing fuels for transmutation in a fast reactor under the U.S. Advanced Fuel Cycle Initiative (AFCI) in order to transmute long-lived transuranic actinide isotopes into shorter-lived fission products [3]."

Jan 1, 2008

By C. J. Lewis

This presentation concerns calcium oxide-better known as high calcium quick lime High calcium quicklime is produced by calcining high calcium limestone, mostly in the many rotary kilns located throughout the United States and Canada. This paper presents suggestions on the handling of lime based on field experience. The subjects covered are chemical analyses, transporta¬tion, lime storage, lime slaking to form a water slurry of calcium hydroxide solids, slurry transportation, slurry viscosity, and scaling of lime slurries. It is hoped that the comments on the foregoing areas will be of use to those designing or operating lime systems.

Jan 1, 1992

By B. Holleis, M. Potesser, D. Spoljaric, H. Antrekowitsch, A. Hengelmolen

"During the past only an optimization of metallurgical furnaces were done without attention on the burners. Nevertheless, furnaces without burners are impossible to use in the primary and secondary nonferrous metallurgy in an economic way. Since the energy cost is increasing and the environmental protection is becoming a global issue, the burners are in the focus of several investigations and optimizations. One possible way is the combustion by oxygen. By using oxygen, the flame temperature increases and therefore, fuel accordingly money could be saved by having a low amount of harmful substances like NOx in the off gas. This paper describes a new burner system which combusts fuel with oxygen or air by diluted combustion, hence low pollutants in the off gas. Furthermore the effectiveness of the burner characterized by off gas analyses and simulation in the new development chamber, but also practical tests at an aluminum smelter are described.IntroductionIn 2005, Messer Group established a technology competence centre for metallurgy in Gumpoldskirchen (Austria), with the aim to develop oxygen burners which satisfy today’s and upcoming standards of legislation as well as customer requirements. With the assistance of the Development Sponsorship Fund (FFF) of Austria, cooperation with the University of Leoben was agreed on. With the long term experience of the Gas-Wärme-Institut “GWI” in Essen (Germany) and the University of Leoben, different new burners have been developed."

Jan 1, 2008

By C. Sui

A common objective in many Cu/Zn concentrators is to reduce the loss of Zn to the Cu-concentrate. One suspected source of the problem is accidental activation of sphalerite by heavy metal ions such as lead. One method of quantifying surface metal ion concentration is extraction with ethylene-diamine-tetra-acetate (EDTA). This was used to survey Cu-rougher flotation at three Cu/Zn concentrators: Les Mines Selbaie, Falconbridge's Kidd Creek division, and Hudson Bay Mining and Smelting Although all have less than 0.2% galena in the ore, Pb ions proved an abundant extractable metal. From a laboratory study a model of surface coverage of lead species generated by an ore was combined with an estimate of surface concentration of lead required to activate sphalerite to explore the possibility of accidental activation. Ores with Pb-grade as low as 0.1% can produce sufficient Pb to be a potential problem.

Jan 1, 1999

By P. K. Narasimhargahavan

This paper discusses briefly the major reasons associated with the growth and its impact on the energy requirement and Environmental imbalance. A projection based on the present global Alumina and Al requirement indicate a substantial further growth of at least 30% over the next 10 years. It is indicated that the main factors which are likely to influence investments are the environmental factors such as the Climate Change and global response to the growing energy prices and sustainable development. Each of the developed / developing nations must find response to the GHG emissions which will encourage the Al Industry to make an effective contribution to global warming while preserving the international competitiveness of the industry - a challenging task. The efforts shall concentrate on improving energy efficiency in the industry possibly of the order of 25% over the next 10 to 20 years. The developments in this line are discussed.

Jan 1, 2010

By Etsuro Shibata

For the treatment of huge amounts of the sulfur which is from the earth by both natural and man-made activities, a harmonized sulfur cycle was presented. The man-made sulfur cycle which includes sulfur circulation from oil, coal and ore was analyzed in detail based on the recent world sulfur trend. Then the man-made cycle was compared with the natural sulfur evolution such as volcano. Finally, the harmony in both natural and man-made sulfur cycles was discussed.

Jan 1, 2006

By Pranav Deshpande

The wear behavior of metal matrix composites differs from that of the monolithic metallic counterparts because composite materials have multiple constituents in their structures and these constituents wear at different rates. It was observed that under low wear stresses, abrasive wear prevailed. As the wear stress increases, pullout of reinforcement occurs and both abrasive wear and wear due to pullout contribute to the overall composite wear. A model of wear taking into account both types of wear has been developed. A critical pullout wear stress was suggested for each composite. Below the critical wear stress, no pullout of reinforcement occurs. It turns out that the critical wear stress simply equals to the ratio of the interfacial strength between the matrix and the reinforcement to the friction coefficient between the reinforcement and the wear counter surface. The critical wear stress is independent of the particle size of the reinforcement. From data on wear of 53% WC composites, the equation of wear for 32% WC composites was obtained. Experimental results agreed well with the predicted wear rate of this composites. This provides an excellent verification of the wear model developed by Lin and Deshpande. Wear data from Modi et al. in the literature were also perfectly fitted with the model.

Jan 1, 2006

By Victor Bredykhin

The reasons of formation low quality cathode deposits and conditions of the anode passivation in electrorefining of copper silver alloys with increased (more then 5%) silver content in electrolyte, g/l: Cu - 40; H2SO4-50; 150 and 250; T= 401C have been investigated. As it is shown, increased acidity, anodic current density and silver content in anodes favor passivation. The assumption is made that the ingress of silver on cathodeis the most probable reason of growing dendrites on cathode. We have determined that addition of ethylene carbonic acid to electrolyte in the amount of 3,5 ÷ 10 ml/l suppresses the dendrite formation.

Jan 1, 2006

By L. Y. Zhang

The current status of metal hydride alloys for NiMH batteries was systematically reviewed. Extensive application-oriented research and development has successfully made the NiMH battery an important part, with growing potential, among rechargeable batteries. The rare earth based metal hydrides (AB5) have been considered the best alloy material for use in the negative electrode in NiMH batteries. However, being in demand for high performance electronic markets, the still young NiMH industry is facing serious technical challenges in developing better products. Among all the efforts to respond to the challenges, advanced AF3, alloys are in great demand: the capacity enhancement race requires new or improved alloys possessing higher volumetric capacity; price competition mandates MH materials with low cost; high performance under severe service environments calls for alloys with high corrosion resistance when subjected to electrochemical cycling; and finally, high power service requires the negative electrode to deliver current at high rates.

Jan 1, 1997

By Cyro Takano

This paper is a contribution to fundamentals data on the equilibrium metal/slag for refining silicon in relation to Ca and Al as impurities. Silicon containing 0.1% Al and no Ca was placed in contact with a slag of various contents of CaO, SiO2 and Al2O3. Slag Al2O3 contents were 11.4%, 25.1% and 29.6%, keeping the ratio %CaO/%SiO2 constant and equal to ~0.53. The experiments were conducted at 1550oC, in a graphite crucible with argon atmosphere. The equilibrium was observed with low and medium content of Al2O3. The derived activities coefficients of Ca and Al in dilute solution of Si presented good correlation with those of the literature. Parallel reactions with formations of SiO(g) and CO (g) were also observed.

Jan 1, 2006

By Sung Wng Kim

The binary antimonide compounds with the skutterudite structure have a potential for thermoelectric applications because of the high carrier mobility, high thermoelectric power, and relatively low thermal conductivity due to the complex crystal structure. However, the room temperature thermal conductivity of these skutterudite materials is as high as about IOW/mK with an estimated 80-90% contribution from the lattice thermal conductivity. Because the lattice thermal conductivity of related ternary skutterudite compounds can be substantially reduced due to the additional phonon scattering, a study of thermoelectric properties of these compounds is of interest. The binary IrSb3, ternary Ir1.xRuxSb3 and Ir(MxSb1.x)3(M=Ge, Sn) compounds were prepared by hot pressing of pre-reacted powders. We have measured the electrical resistivity, thermoelectric power, and thermal conductivity, in a temperature range from room temperature to 973K. The binary IrSb3 compound is found to have P-type electrical properties exhibiting a good Seebeck coefficient (up to 225µV/K around 773K), electrical resistivity(5x10-5Ohm M around 933K), and relatively low thermal conductivity(6W/mK around 950K). The lattice thermal conductivity, K[2] was calculated from the Wiedemann-Franz relationship.

Jan 1, 2002