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By Fang Wu

The paper designs an extraction flow for the total recovery of nickel and cobalt and removing magnesium simultaneously from the cadthodic materials of the spent hydrogen-nickel and cadmium-nickel batteries. The separation of Co, Ni and Mg though P507 extraction .The extraction equilibrium pH is 4.5~5.0, ßNi/Co is 140~180, and ß Ni/Mg is 20~25; nickel and magnesium are scrubbed in two steps, in which the equilibrium pH of nickel and magnesium scrubbing is controlled at 5.0±0.1 and 4.4±0.1 respectively. The stepwise scrubbing technique is adopted to remove 94.5% of magnesium and to recover 99.45% of nickel and 95.35% of cobalt. During the integrated extraction and precipitation process the total recovery fraction of nickel and cobalt are 99.99% and 99.95%, and the recovery fraction of magnesium is 94.02%.The recovered NiSO4 and CoSO4 solution are enriched and crystallized.

Jan 1, 2009

By Christophe Thiébaut

Keywords: Pyrochemistry, Salts Treatment, Distillation The pyrochemical purification of metal generates spent salts. When this metal is an actinide such as plutonium, the slags cannot be discarded and are thus disposed in nuclear facility. In order to handle with these slags, the decision has been taken to reduce stored quantities. The development of a pyrochemical treatment is in progress in the CEA Valduc centre. The feed salt, typically composed of various Pu and Am species contained into monovalent or divalent chloride matrix, is first oxidized to convert the actinides into oxides. Then the chlorides are separated from the actinide oxides by vacuum distillation. Temperatures higher than 750°C for monochloride salts mixture NaCl/KCl and higher than 1100°C for divalent CaCl2 base salts, are required to produce an industrial flow of vaporization. Inactive qualification of the process for NaCl/KCl base salt has been carried out with lanthanide surrogates. Then, a pilot equipment, called distillator has been designed and built for production-scale distillation of NaCl/KCl and CaCl2 oxidized plutonium salts. Industrial flows of vaporization have been obtained with this pilot equipment : about 4 g/cm²/h for NaCl/KCl at 800?900°C and 1 Pa, and more than 1,5 g/cm²/h for CaCl2 base salts between 1000?1200°C at 0.1 Pa. The last step, now in progress, is the integration of the distillator into a glove box.

Jan 1, 2005

By Guangqing Zhang

The paper presents results of a systematic study of synthesis of titanium oxycarbide and its chlorination. Titanium oxycarbide was produced by carbothermal reduction of titania in hydrogen, argon and helium. Formation of titanium oxycarbide started at 1200°C in all gases. The reduction was the fastest in hydrogen. Formation of titanium oxycarbide in hydrogen was close to completion in 120 min at 1300°C, 60 min at 1400°C and less than 30 min at 1500°C. Reduction in argon and helium progressed at a similar rate and reached 90-95% after 300 min at 1400-1500°C. The chlorination of titanium oxycarbide was ignited at 150-200°C. Chlorine partial pressure and gas flow rate strongly affected the chlorination rate. Chlorination of titanium oxycarbide produced with carbon to titania molar ratio 2.5 at 235-400°C was close to 100% in 30 min.

Jan 1, 2009

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 S. Tanaka

The Tamano Smelter of Hibi Kyodo Smelting Co. Ltd. was commissioned in 1972. Since start up, the anode production capacity has increased from 101,000 tpy to 290,000 tpy, as a result of the application of continuous improvements at each phase of the expansion projects. The Tamano Smelter had developed several innovations, including the original coke combustion technology for Flash Smelting Furnace operations (T-FSF), and has also been able to extend the operating life of the Peirce-Smith converters. This paper will present several improvements implemented at the Tamano Smelter, and will discuss relevant P-S converter operation.

Jan 1, 2005

By Tsunehisa Nishimura

Stable operation of the blast furnace needs adequate control of the lower part. To clarify the behavior of the lower part of the blast furnace with accurate consideration of the property of slag and its flow characteristic, a new mathematical model has been developed. Using this model, the effects of the change of operational conditions on the behavior of the lower part of the blast furnace were studied. Further, means to control of the lower part of the blast furnace, especially effective means to maintain adequate temperature, were discussed. And desirable slag property and composition, especially the method to control FeO concentration dripping from the bottom of the cohesive zone to avoid a decrease in temperature of the lower part of the blast furnace was estimated.

Jan 1, 2006

By Elisa Alonso

Recycling is generally a more sustainable alternative to landfilling. Its financial costs however, do not always justify its practice, especially in the short term. As a result, even for precious metals such as platinum, significant amounts can end up unrecovered. In considering risks of materials scarcity for firms that require platinum and platinum products, this paper examines how recycling provides additional benefits as a risk-mitigating strategy against scarcity. The experimental platform for this examination is a System Dynamics simulation model that strives to capture the dynamics of platinum market supply, demand and price. The detailed structures of supply and demand are key features of the model. Results show that since the secondary supply of platinum depends on a supply chain separate from primary extraction, recycling can diversify the risks of primary supply instabilities and reduce the impact of price fluctuations upon firms.

Jan 1, 2009

By Wilson Acchar

The accelerated growth of urbanization processes and current environmental concerns brought to light the existing enormous quantity of construction and demolition waste (C&DW). Considering the frequent lack of adequate landfill areas available for the disposal of these materials, their use in the manufacture of ceramic products has been attracting a growing interest from researchers and is becoming common practice, with the consequent relief in public administration concerns for the C&DW appropriate management. This work describes the study of clay-based products added with C&DW collected directly from the construction industry. Samples containing up to 50 wt.% C&DW were uniaxially pressed and sintered in air in an electric furnace (950-1150 °C, 1 hour). Sintered test pieces were characterized by X-ray diffraction, apparent density, open porosity and flexural strength. The results showed that up to 50 wt.% C&DW can be added to the clay material, with no degradation in the final product properties.

Jan 1, 2009

By M. Hochenhofer

Keywords: desulfurization, mathematical model, slag reaction To produce ferroalloys like ferro-nickel for alloying purposes in a quality that meets the requirements of today?s steel industry, refining processes like desulfurization and dephosphorization are indispensable. The performance of desulfurization-treatment by slag reaction depends on various parameters, such as: sulfide capacity and viscosity of the slag, sulfur distribution between metal and slag, activity of sulfur in melt and movement of melt. Within this work, the combined influences of these parameters on the desulfurization of a ferro-nickel alloy were examined. As a basis for this examination, a mathematical model, based on data from plant trials, was created. This model demonstrates the relationship between desulfurization rate and initial values of the above mentioned parameters. With this model the relevant parameters were evaluated and assessed concerning their influence on desulfurization.

Jan 1, 2005

By Carlos Maurício Fontes Vieira

In the present work a ceramic body, fabricated using a mixture of clays and sand, for roofing tiles, produced in Campos dos Goytacazes, north of the State of Rio de Janeiro in Brazil, was characterized. Characterization was performed by X-ray diffraction, thermo analysis, chemical analysis, particle size distribution determination and plasticity. In addition, technological properties related to water absorption, linear shrinkage and flexural rupture strength were determined in samples fired at 700, 900 and 1100oC. The results showed that the investigated ceramic body has satisfactory plasticity and presents a refractory behavior during firing due to the predominantly kaolinitic nature of the clays.

Jan 1, 2006

By Olga Karabelchtchikova

Keywords: Multipass grinding, Residual stress, Retained austenite, X-ray diffraction The study investigated residual stresses behaviors and their superposition effect in D2 dies for thread-rolling applications. A nested factorial experiment was applied to test hypotheses that the residual stresses profiles change due to combination of heat treatment and multipass grinding operations, and that certain patterns can be derived due to the memory relationship between pre-existing and final residual stresses distributions. The amount of the retained austenite along with residual stresses in variation with depth was measured using x-ray diffraction technique. Statistical analyses indicate that the proposed hypotheses hold. Residual stresses distributions as well as tensile peak location were found to be significantly influenced by the treatment parameters used. Unique characteristic patterns in the residual stresses profiles were observed due to multipass grinding technique across all experimental conditions. This finding suggested a plausible memory relationship between the cutting passes, and the causes of the foregoing results are further proposed and discussed.

Jan 1, 2005

By Theo Lehner

Turning matte into anodes continues to be an area to watch: for visitors to see pyrometallurgy in action; for metallurgists to keep up with modern smelting furnaces and ever increasing production rates; for management to remain profitable using more tools than taught in school; and for environmentalists to detect the last small clouds from the ever cleaner smelter. Current converting practices have been screened and analyzed, and today, converting and casting is a modern industry. An impressive, though typical learning curve of converter productivity may be detected. Local conditions such as availability and type of raw materials, products extracted, cost factors, etc., have stimulated the development of add-ons or even alternatives to the still dominant method of converting by Peirce-Smith technology. Turning blister copper into anodes follows a similar path, namely increased productivity and improved quality. We dare to predict that development will continue.

Jan 1, 2005

By Junji Shibata

Keywords: Synergistic effect, Solvent extraction, Nickel ion, extractant mixture Waste solution from the Ni non-electric plating process contains 4.0 kg/m3 Ni (II), 0.1 kg/m3 Fe (III), 0.01 kg/m3 Zn (II), 48 kg/m3 SO42-, 98 kg/m3 HPO32- and 31 kg/m3 lactic acid as a typical composition. Solvent extraction, cementation, ion exchange resin and precipitation methods may be used for the treatment of this kind of solution. In this study, solvent extraction of Ni (II) is investigated by using two kinds of extractants in order to clarify the relationship between extraction equilibrium (static synergistic effect) and extraction rate (dynamic synergistic effect) for several extractant mixtures. The static synergistic effect does not take place significantly for the extractant mixtures of acidic extractants and neutral organphosphorous compounds, while a large static synergistic effect is confirmed when the extractant mixtures of acidic extractants and nitrogen-containing compounds are used. Nickel ions can be extracted in the wide pH range of 3.0-8.0 without any pH adjustment by using the several extractant mixtures. At the same time, the extraction rate remarkably increases by using the extractant mixtures of acidic extractants and nitrogen-containing compounds.

Jan 1, 2005

By Chang-Dong Li

Cadmium ingot and nickel powder were prepared by high-temperature distillation, solvent extraction and liquid phase reducing method with spent Cd-Ni batteries as raw material. The impacts of the temperature in the distilling stage, the concentration of H2SO4 in the leaching stage, the pH value in the extracting stage and the dosage of hydrazine in the reducing stage were discussed respectively. The as- prepared samples were characterized by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic absorption spectrometry (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The results showed that the recovering efficiencies of Cd and Ni reach 99.5% and 99.3%, and the purities of Cd ingot and nickel powder were higher than 99.90% and 99.80%, respectively.

Jan 1, 2009

By Emmanuel N. Zevgolis Ismene-Polyxeni Kostika

Keywords: reduction, kinetics, laterites, rotary kiln, dust In this work, the reduction kinetics of dust from nickeliferous Greek laterites is investigated. The dust is a by-product from laterite treatment in rotary kilns and it comes from washing towers, electrostatic filters and polycyclones. Laboratory made pellets from this dust were also examined. Reducibility was studied in the temperature range of 700°C to 850°C in a laboratory tube furnace. Kinetic analysis of the results showed that at lower temperature values the mixed kinetic model verifies the experimental results of dust and pellet samples. At higher temperatures (800° and 850°C) diffusion becomes the rate controlling mechanism. The calculated activation energy values verify also the above mentioned results.

Jan 1, 2005

By Zhendong Tao, Wei Huang, Zhongxi Yang, Hang Guo, Haoran Geng, Jingxiang Yao

"CaSO3.0.5H2O typed Flue Gas Desulfurization (FGD) gypsum is a by-product formed in flue gas desulfuration by double-cycle fluid bed method, its composition is different remarkably from that of gypsum yield by normal desulfuration methods, and few studies using it as cement retarder have been carried out. In this paper, the experimental study using CaSO3•0.5H2O typed FGD gypsum as cement retarder was carried out. The experimental results indicate that, when FGD gypsum is added solely into cement, the retarding action is not satisfactory because of its slow dissolution rate; The composite retarder composed of FGD gypsum and natural gypsum can regulate efficiently setting time of cement over a wide range of addition and rate of both each other, and the mechanical property of cement can be improved significantly.Fire-power plants have discharged a lot of harmful gases such as SO2 etc., which has resulted in serious pollution on the environment. To reduce harmful gas containing sulfur in the flue gas, various flue gas desulfuration (FGD) techniques have been developed. At present, the FGD method used widely is to add desulfuration agents such as limestone powder or other calcareous-contained materials during the coal burning or in the flue gas so that the components containing sulfur react with them to form solid sulfate or sulfite and to be separated from the flue gas by collectors. CaSO3•0.5H2O and CaSO4•2H2O typed FGDgypsum can be obtained respectively by dry and wet FGD process[1,2]. As a by-product of fire-power plant, features of of FGD gypsum and its applications have been paid great attention. Pavel Tesa'rek et al [3] presented in full the characters and properties of FGD gypsum; Zofia Konik et al[4] prepared expansive additive used to cemnent industry by using FGD gypsum and aluminate clinker; A. K. Alva et al [5] investigated the effects of FGD gypsum and fly ash on soil properties and found the growth of seedlings of either rootstock improved significantly in soils amended with FGD gypsum and fly ash. FGD gypsum also can be used in gypsum binders, plasters and plasterboard manufacture [2.6]. C. S. Poon et al [7] investigated the effects of FGD sludge on the pozzolanic reaction of reject-fly-ash-blended cement pastes. Many studies using CaSO4•2H2O typed FGD gypsum as cement retarder has been reported[2,8-12]. Howevere, few studies using FGDG as retarder were reported so far. In present study, the chemical compositon, phase composition, structure and features of CaSO3•0.5H2O typed FGD gypsum have been analyzed, and its application characters used as cement retarder have been investigated experimentally."

Jan 1, 2008

By J. C. Huyhua

The effect or various oxidants on gold and silver dissolution in thiourea solutions (0.05 M in H2SO4) was studied using the rotating disc technique, a.t 2s c and 600 rpm. These studies were carried out at constant (4:1) initial molar ratio or thiourea to oxidant concentrations, to produce 50 % thiourea. oxidation. The initial dissolution rate of gold was approximately four times higher in the presence. of ferric sulfate (5.37 x 10-3mg cm-2 s-1) than in the presence of hydrogen peroxide (H2O2), potassium persultate (K2S2O3), or monopersulfa.te (KHS06). The dissolution rates for silver were considerably lower than gold for the same oxidants. Oxidation of thiourea in the presence of peroxygen and persulta.te compounds is a. fast reaction and it is completed in less than ten minutes. On the other hand, the oxidation or thiourea with? ferric.sulfate is slow, yielding a second-order reaction rate constant k = 6.09 I mol-1 h-1. Sulfur formation in the ferric thiourea system begins when ferric ion reduction approaches to completion. With hydrogen peroxide, sulfur is observed at lower thiourea concentration than ferric. Suifate. The presence of a large excess or free thiourea i.e., s to 20 % thiourea oxidation) retards sulfur formation and maintains favorable dissolution rates. Finally, carbon-in-leach experiments indicate that thiourea solutions a.re stable for several days, with ferric sulfate or hydrogen peroxide. The dissolution rates of gold and silver doubles in the presence or activated carbon when hydrogen peroxide is used as oxidant.

Jan 1, 1989

By Sayavur Bakhtiyarov

Keywords: Rheology, Viscoelastic, Oil In this paper we present the results of the rheological property measurements on viscoelastic composite materials used in oil industry. Laboratory experiments were carried out to determine important thermophysical, rheological and mechanical properties of the test materials using both the standard commercial and in-house made equipment. The composites with the paramagnetic particles (?-iron oxide) are exhibited a significant magnetic memory after magnetic treatment. The measured value of the yield stress after the magnetic treatment increased almost twice in comparison with the yield stress value of the magnetically untreated composite. The yield stress of the composite material exponentially decreases with time and reaches its magnetically untreated value after 15 hours. The yield stress also increases with the amount of the paramagnetic powder additive, and it reaches a maximum value at 8 wt-% of this additive. The obtained results provide valuable information for computer modeling of the viscoelastic fluid flow in pipes of complex geometry.

Jan 1, 2005

HW Process Technologies, Inc. (HWPT) has developed a patented membrane-based ion fractionation system, which specifically separates copper from gold and silver species in a cyanide matrix. This Engineered Membrane Separation (EMS?) system was pilot demonstrated on the 82,000 liters of pregnant leach solution' (PLS) generated from tailings, via thin layer leaching, at a mine site in Durango State, Mexico. The EMS? recovered ~90% of the gold-silver cyano-complex to a 90% volume permeate (based upon an EMS? feed stream of 100% volume) while rejecting -90% of the copper cyano-complex to a \0% (by volume) concentrate. The EMS? technology combines pore-size specific electro-statically charged membranes with engineered materials of construction and application-specific operational design that reject multi-valent, ionically charged species to the concentrate and transmit mono-valent species through the membrane to the permeate. The 850 ppm Cu PLS contained approximately 0.8 gil free NaCN with, the copper cyano-omplex principally in the CU(CN)3 and CU(CN)4 forms. The gold grade of the PLS was -2 ppm Au. The ~LS calcium concentration at -700 ppm Ca was reduced to ISO ppm.Ca (± 50 ppm) by sodium cycle ion exchange pre-treatrnent prior to EMS? processing.

Jan 1, 1998

By Leonardo Mota, Felipe Perissé Duarte Lopes, Marcelo Gomes da Silva, Sergio Neves Monteiro, Helion Vargas

"Natural fibers, as a class of material, are attracting the interest of engineering sectors owing to specific advantages such as comparatively reduced cost and lower density as well as environmental benefits associated with renewability and biodegradability. For industrial applications, thermal properties, among others, are required. These are major requirements, especially in the case of an insulating natural fiber. In the present work, thermal properties of the curaua were investigated by photothermal techniques, i.e., the open photoacoustic cell and a method based upon the monitoring of the temperature evolution as a function of time. This investigation, in tum, permitted to evaluate two important thermal properties: the thermal diffusivity and the specific heat capacity of the curaua fibers. Indirectly, by means of simple mathematical relations, the thermal conductivity was also obtained. The results were compared with other materials and characterize the curaua fiber as an efficient insulator.IntroductionMaterials are gaining attention in recent years owing to their benefits for the environment as compared to synthetics. Being biodegradable, yearly renewable and recyclable, the natural planted-based are considered fully sustainable [1]. In particular, their life-cycle, from growing to industrial processing, absorbs as much C02 as it is emitted and makes them neutral with respect to greenhouse gases responsible for global warming [2]. Typical examples of these environmentfriendly materials are the lignocellulosic fibers that have been used in simple items such as ropes, baskets, textile, modest roofing, etc, since the beginning of our civilization [3]. In the past few decades, these natural fibers have been extensively investigated [ 4-1 O] as a possible reinforcement phase of polymer composites in substitution for synthetic fibers. In fact, engineering application of lignocellulosic composites are today in the market, especially in the automobile industry [11-13]. Out of the hundreds available natural fibers, only part of them exhibits superior properties to be qualified for composite reinforcement."

Jan 1, 2011