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By Terence Makanyire, Animesh Jha

The dissolution and chemical properties of vanadium, zirconium, and niobium in rutile lattice are analyzed by comparing the octahedral site preference energies, with respect to Ti4+ ion in the solvent phase. The oxides are often present in rutile lattice and interfere in achieving the quality of pigment grade TiO2 due to favourable Gibbs energy for dissolution in the solvent rutile matrix. Binary mixtures of V2O5 { TiO2; Nb2O5 { TiO2 and ZrO2 { TiO2 with compositions of 80, 85, 90, 95 and 97 wt% TiO2 were made, pelletized and sintered at 1100 °C for 24 hours. The solidsolution mixtures were then cooled and leached in 2M NaOH for 3 hours at 60 °C. Phase and lattice parameter characterizations, and microstructural and compositional analyses were then carried out using X-ray diraction and SEM/EDX, respectively. The leachates were analysed by Atomic Absorption Spectroscopy (AAS), using which the solute dissolution model for oxides were investigated.

Jan 1, 2014

By Min Chen, Nan Wang, Zhen Tian, Yingying Shen

"The enrichment behavior of phosphorus in CaO-SiO2-FeOx-P2O5 slag was studied by making an investigation on the distribution of phosphorous content in slag and 2CaO·SiO2 phase. The research results showed that the existing 2CaO·SiO2 solid particles in slag were the sites for the phosphorous enrichment. The enrichment process of phosphorus in CaO-SiO2-FeOx-P2O5 slag can be recognized as: mass transfer of phosphorus from bulk slag toward the surface of 2CaO·SiO2 particle, superficial dissolution reaction of phosphorus to 2CaO·SiO2 and diffusion of phosphorus through the product layer of 2CaO·SiO2-3CaO·P2O5 solid solution to the inner of 2CaO·SiO2 particle. Compared to the 2CaO·SiO2 particles with larger size (500µm to 1000µm), the completion time of enrichment was shorter for the particles with smaller size (less than 50µm).IntroductionDuring ironmaking and steelmaking, significant amounts of slag are produced. Contrast to the high utilization of ironmaking slag, the treatment of steelmaking slag is more difficult and challengeable, and therefore, an alternative approach is to recycle the steelmaking slag inside the ironmaking and steelmaking process itself. The main limitation to the reuse of steelmaking slag inside the process is that the refining process may be aggravated caused by the phosphorous accumulation if it is used in the blast furnace burden [1]. At the same time, the phosphorous content of steelmaking slag (approximately 1%~5% P2O5) is too low for it to be used as raw material for fertilizer [2, 3]. Moreover, owing to the diminishing supply of global iron ores with low phosphorous content, the control of phosphorus in iron and steelmaking processes has become an increasing problem, and as a result, more amounts of high phosphorus containing steelmaking slag are produced. Therefore, a valuable approach is quite appreciated in which the steelmaking slag is recycled within the ironmaking and steelmaking process and at the same time, the high phosphorus-containing phases in the steelmaking slag, suitable for use as fertilizer can be separated and recycled effectively [4]."

Jan 1, 2011

By Haydar Güneş

In this study, a hydrometallurgical process was evaluated for the recovery of Nd from a Nd-Fe-B magnet. Each leaching test was performed at the solid (weight) to liquid (volume) ratio of 1:50 and was mixed at 400 rpm at ambient temperature. The effects of 3 different acids (HCl, HNO3, and H2SO4) on the extraction of Nd were investigated and H2SO4 was found to be more effective than other acid solutions. Under the optimal conditions, pregnant leach solution was produced with H2SO4 for subsequent Nd precipitation testing. Each precipitation test was carried out using 100 mL of feed solution mixed at 600 rpm at 25°C. NaOH and H2C2O4 were used for Nd precipitation. The highest Nd was precipitated as Nd2(C2O4)3, 10H2O with C2H2O4 at 20 min.

By Marie-Aline Van Ende, In-ho Jung

A thermodynamic database for the oxyfluoride system CaO-MgO-Al2O3-SiO2-Na2O-K2O-Li2OMnO- FeO-F has been developed based on the critical evaluation and optimization of all available experimental thermodynamic and phase diagram data. The developed database can be used for phase diagram and equilibrium solidification calculations for multicomponent systems and for understanding the solidification behavior of mold fluxes. Based on this thermodynamic database, a simple kinetic model was developed to simulate the interactions between the mold flux and molten steel using effective equilibrium reaction volumes combined with the thermodynamic database.

Jan 1, 2014

By Yasumasa Hattori

An extensive study including fluid dynamic calculations, cold model tests, pilot plant tests as well as measurements in a commercial flash furnace was carried out in order to develop a new Sumitomo flash smelting concentrate burner. The pressure measurements in the commercial burner indicated that the premixing of the concentrate and reaction air in a burner was insufficient. Pilot plant tests showed that enhancement of the premixing of the concentrate and reaction air is very effective for improving the burner performance. Using the additional pressure drop of the reaction air as an indicator of the premixing, a new type Sumitomo premixed concentrate burner was developed.

Jan 1, 2003

By Klaus Gamweger

"This paper introduces an innovative solution to open and close the tap hole of different furnace types in the copper industry with a slide gate system. Two plates with defined drilled holes are slid against each other, which enables effective starting and stopping of the copper flow as well as throttling. Typically, the copper is poured via a tap hole into a launder system by rotating the furnace into an appropriate position. Control of the casting rate is also performed in this manner. Or, in case of stationary furnaces the tap hole is opened by oxygen lancing and closed manually with a clay- or copper-cone. These procedures show a lot of disadvantages including splashing, oxygen pick-up, and energy losses as well as a severe danger for the working staff. All these problems can be overcome with an appropriate slide gate system.IntroductionThe control of the casting rate of a copper anode furnace usually is performed by rotating the furnace into an appropriate position. This implies that the taping starts with the tap hole at a very high position. Copper splashing and an uncontrolled oxygen pick up are - with several more disadvantages - the consequences. RHI AG has developed an innovative solution for copper applications to open and close the tap hole with a slide gate system which allows also an accurate control of the flow rate. By using this system it is possible to start the casting procedure with the tap hole at the deepest position, directly above the launder. This paper presents this new slide gate system in detail and shows the advantages in production and safety issues."

Jan 1, 2012

By J. Boitano

This paper discusses the study, design and implementation of the new gas handling system for the Caletones Smelter of Cbdelco..Chile. A discussion on design conditions for a Mure Sulphuric Acid Plant using Teniente Converter.gases.is also included. The old system which started to be modified in 1985 and relied on natural draft and used balloon flues, resulted in a limited .gas handling capacity for operation under Mure process conditions. This system also caused excessive fugitive gases in the smelter working areas. The new system permits handling of process gases from the higher capacity Teniente converters installed in 1987-1989 Improving the gas handling of the reverberatory furnaces and Peirce-Smith converters as well as the environmental conditions of the smelter. This system utilises improved converter gas hoods, evaporative cooling and electrostatic precipitators gas cleaning, and is based on natural draft.

Jan 1, 1992

By G. Hanko, A. Lebleu, M. Sibony, J. Lecadet

The New Jersey distillation process is today the most important pyrometallurgical method for the production of zinc of very high purity. The flexibility of the pyrometallurgical zinc production process, especially its ability for recycling, makes it competitive, although it is energy intensive. A deeper knowledge of the New Jersey process is necessary to further increase its technical performance by ensuring its global safety. A project, integrated in the European research program EUREKA, has been started in order to define the process chemistry of distillation. Experimental measurements have been carried out with a column at the laboratory scale, and the results, linked with industrial measurements, support the development of a model based on material and thermal balances. The first conclusions indicate that the key parameters for process optimization are the column geometry and the distribution of the thermal losses.

Jan 1, 2000

By Ledjane Barreto, Tulio Flávio Accioly de Lima e Moura, Wilson Acchar, Antonio Carlos Silva da Costal

"Clays are common ingredients in pharmaceutical products both as exclplents and active substances. Clay minerals are naturally cationic exchangers and they may undergo ion exchange with basic drugs in solution. Smectites, and montmorillonite have been studied due their high cation exchange capacity as compared to other silicates. Recently a patented study reports the use of attapulgite as the encapsulating agents both for the protecting the active substance and modulating release into the body. Some clays such as kaolinite, smectites, talc, etc are also used as dermatological protectors. Sepiolite and smectites have the ability to form complexes with organic compounds with absorb ultra-violet radiation, enabling them to be used in sun screens with protection factors. The objective of this work is to characterize the attapulgite in order to study the potential use of this clay material in the human health.IntroductionSince the begimling of time, nature has served humanity as a source of various raw materials. Among these, clays such as kaolinite and ilitte are common ingredients in the tile production. Recently, special clay materials have been investigated in order to identifY new potential uses of these class of materials. Clay materials are natural raw material and have excellent properties such as low toxicity, good biocompatibility, making them a good material to be used in biological applications. Attapulgite (paligorskite) and sepiolite is so called special clays. These special clay materials are very sin1ilar and have a great potential to be used in some technological areas due their special catalytic, sorptive and colloidal-rheological properties [1-8]. Recently some works have reported the use of these special clays materials for many applications such as drug delivery, wound dressing, oil absorbent, pesticides, fertilizers [9-12]. Brazil has a significant reserve of attapulgite located in Piaui state, making the study of the potential of this mineral in special areas, very attractive. Attapulgite is classified a fibrous alluminous silicate material and shows the presence of micro pores and channels, fine particle size and high surface area making this material a good candidate alternative material to be used in many industrial applications [6,8,9,11,12]. The objective of this work is to characterize the physical and microstructure of attapulgite."

Jan 1, 2012

By Tobias Pröll, Bernhard Kronberger, Joachim Rohovec, Werner Hölt, Hermann Hofbauer

"As this is only a first draft, more precise explanations as well as detailed schemes, figures and plots will be included in the final draft. The description og the 100 kW test rig will also be mor detailed as construction is ongoing and will be finished during the summer. Furthermore simulations are to be finished shortly; so details on combustibles and gas concentrations will also be included in the final draft.AbstractOxyFuel combustion is a key technology for the efficient separation of CO2 from fuel combus¬tion (especially coal). Since coal plays a minor role in the Austrian energy mix the application of OxyFuel towards other fuels (biomass, waste fuels) is interesting to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alter¬native fuels is also interesting from a strategic point of view in order to generate knowledge for operation of capture ready cofiring and waste/sludge-incineration plants. OxyFuel uses a synthetic mixture of 02 and recycled exhaust gas where the 02 content may vary. This supplementary degree of freedom allows improved operation especially for low calorific fuels. Heavy fuel oil addition for low calorific combustibles can be omitted when using OxyFuel combustion. Application of alternative fuels (wood, waste wood, municipal waste, sewage sludge) in a 100-kW CFB plant is investigated in combination with process simulation.IntroductionOxyFuel combustion is discussed as one of the key technologies for the efficient separation of CO2 from combustion of fossil fuels (especially coal). Since coal plays only a minor role as primary energy source in Austria, the broadening of the scope towards OxyFuel of other fuels like biomass or waste fuels is necessary to reduce greenhouse gas emissions from Austrian energy sector. The investigation of OxyFuel technology for alternative fuels besides the large coal-oriented projects is interesting also from the strategic point of view. The presented project aims at the generation of knowledge in order to design and operate capture ready cofiring and waste/sludge incineration plants."

Jan 1, 2008

By S. Ikenobu

This paper describes a method for processing high-silicate zinc concentrates by hydrometallurgical zinc refining. Silica in concentrates reacts to form zinc silicate during roasting. The zinc silicate readily dissolves and slowly precipitates in sulfuric acid solutions during leaching. However, if proper operating parameters are not maintained, the colloidal silica may form an unfilterable gel. That is, according to the investigation results obtained, the silica concentration in the reactor has to be maintained at 5 g/1 or less (preferably 2 g/1 or less) by promoting the precipitation reaction. The proposed method has made it possible to precipitate silica in a form having excellent solid-liquid separation characteristics, without the need for facilities having a high filtration capacity, and to maintain a low silica concentration in the reactor by feeding a composition containing pre-adjusted silica contents.

Jan 1, 2000

By Jerome P. Downey

Technologies developed within the field of extractive metallurgy to recover, concentrate, and purify metals and industrial minerals from ores, have served as the foundation for all of the subsequent environmental remediation, materials recycling, and waste management technologies. This paper discusses the application of classical extractive engineering principles to the development of a thermal process for the recovery of mercury from solid wastes. Process development is presented as a series of logical stages, which begin with a thorough characterization of the site-specific waste, move on to bench and pilot scale testing of the process options, and end with a functional process flowsheet. This paper also presents thermodynamic data on many mercury species of interest to the minerals, power, and chemical industries. These data can be used to model the speciation and recovery of the mercury as a function of various process parameters.

Jan 1, 2003

By Jyri Talja, Shaolong Chen, Hannu Mansikkaviita

"For optimum smelting results, proper treatment of the feed is needed to ensure favourable conditions for ignition characteristics, heat balance, mass balance with tolerable impurity levels, and overall process economics. Feed preparation consists of physical treatments before drying (blending), chemical treatments before drying, (roasting, if required), drying itself and physical treatments after drying (fractioning, if required).Effects of fluctuation on mineralogy and moisture should be minimized by blending the concentrates in a bedding plant prior to drying. As an alternative to drying, additional treatments such as roasting for impurity removal may be needed for part of the concentrate.Sustainability, energy efficiency, utilization of waste energy, low gas and dust emissions, product quality, availability and occupational exposure reduction are decisive criteria in drying today. These criteria are best met by the Kumera steam dryer, which has the best energy efficiency, zero CO2 emission, lowest operational and maintenance expenses, and superior availability and product quality.IntroductionFeed preparation plays a crucial role in having a smooth smelting operation and also the overall smelting economics in metal production. Therefore, it is of significant importance for all copper, nickel and lead smelter operations in which sulphide concentrates are fed to the primary smelting furnace. Generally speaking, the higher the metal content in the matte after primary smelting, the more important the feed preparation. This is of particular importance in the direct blister (DB) process for copper production and direct oxygen nickel (DON) for nickel production.Bedding is the first stage in feed preparation. This is very important for the sake of smoothing the mineralogical fluctuation in the feed for better smelting control. Its importance increases as the number of concentrates available for the feed mix decreases."

Jan 1, 2012

By Donald J. Hallbom

Limonitic nickel laterites slurries exhibit complex rheological properties including time dependency that varies from thixotropy to rheopexy. Chronic problems may occur if plant designers and operators fail to take time dependency into account. Stress decay tests indicate that laterite slurry takes roughly two minutes to approach steady state after a step change in the shear rate. As a result, most rheometer measurements are taken at a non-equilibrium state, making evaluation difficult. Two minutes is also long relative to the time that a unit of slurry in a processing plant is at any given shear state, so the slurry may never reach equilibrium. This paper presents a method to describe the rheology of laterite slurry using a Flow Array, which describes the rheology using an array of instantaneous flow curves crossed by an equilibrium flow curve. A rate equation for structural change in non-equilibrium conditions allows time dependence to be efficiently modeled. This flow array allows the flow behavior of time- dependent slurry to be predicted in non-equilibrium conditions using a simple time-step methodology. Keywords: Rheology. nickel laterite, hydraulic transport, pressure acid leach, flow array

Jan 1, 2004

By Brian Lightfoot

Ausmelt technology is a versatile bath smelting technology with application in many waste treatment fields at low capital and operating cost. Heavy metals extracted from wastes may be recycled to mainstream use and the slags produced will be inert and suitable for use as aggregate, shotblasting grit or other applications.

Jan 1, 1994

By Helmut Attlfellner

The selection of the best process for the oxygen generator for a metallurgical process requires the determination of all aspects which impact the economics of this facility. Concepts and features of modern air separation plants will be presented based on installed facilities for various metallurgical processes. The special features of advanced automation' of oxygen generators with load following and optimization of power consumption, automatic restart and unattended remote controlled operation will be investigated.

Jan 1, 1992

By Kiyoshi Shibata, Jun-ichi Hayashi

"Steel making technology poses strong potentials for environmental protection in three direction. One is pollution control on steel making process itself. Japanese steel industry has cut down various type of emission drastically since 1970's. Secondary, those process technology can be applied to reduce environmental burden in other industrial sectors. One of the successful examples is municipal waste treatment facility. Thirdly, development of high performance steel products, such as high strength steel for automobile body, can contribute to improve environmental performance during their use, based on the concept of life cycle assessment. Some examples of the successful development and future task is discussed.IntroductionsStack and smoke used to be a symbol of energy intensive industry such as steel making. But, scenery of steel works and its surroundings have been completely changed, and steel products have been changing, as well. The steel making industry consumes huge quantities of energy and resources. Variety of technical development have been carried out to reduce the pollutant release. The steel industry in Japan has been making direct and indirect contributions to reducing of various kinds of environmental impacts through development of high-performance process and products: Its potential technical capability accumulated in steel making is fundamental and essential infrastructure for the vein systems of our society. In this paper, the activity of steel making industry for better environment is discussed"

Jan 1, 2000

By Anjali Talekar

Low temperature heat capacities of pentaerythritol [PE: C(CH2OH)4], pentaglycerine [PG: (CH3)C(CH2OH)3], and 2-amino-2-methyl-1,3-propanediol [AMPL: (NH2)(CH3)C(CH2OH)2]have been determined by adiabatic calorimetry from 3 K to 300 K. To the best of our knowledge, this is the first reported heat capacity measurement below 280 K for PE and AMPL. The Debye temperatures for these organic crystals have also been determined and compared with other alcohol derivatives of neopentane.

Jan 1, 2006

By Leo Brewer, Kazuyoshi Shimakage, Mamoru Mitomo, Toshiyuki Nishimura, Yoichiro Uemura, Shinji Hirai

"In the synthesis process of ß -La2S3 via the sulfurization of La2O3 powder using CS2 gas, La2O2S was formed. This occurred at an initial stage of the reaction for sulfurization temperatures below 973K, and ß -La2S3 was also formed at a shorter period for higher sulfurization temperatures. It was found that the oxygen content in ß -La2S3 powders decreased gradually with an increase in sulfurization temperature. On the other hand, the carbon content in these powders increased gradually with an increase in the sulfurization temperature. Though it has been reported that ß -La2S3 was transformed to Y -La2S3 at 1723K± 50K, the sintered compact of double-phase Y -La2S3 and ß. -La2S3 was formed at a rather higher temperature of 1973K when the synthetic powder of ß -La2S3 containing a high amount of oxygen was used. However, phase transformation of -La2S3 to Y -La2S3 progressed preferentially with a decrease in the oxygen content of synthetic ß -La2S3 powder. The Seebeck coefficient of the sintered double-phase Y -La2S3 and -La2S3 was higher than that of the single-phase Y -La2S3, reported previously.Introduction La2S3 exists in three polymorphic forms that are similar to a series of Ce2S3, Pr2S3 and Nd2S3: a, ß , and Y'. The a -La2S3, which is stable at low temperature, is irreversibly transformed to ß -La2S3 of various compositions in the solid-solution range between La2S3 and La3S4, at 923 ± 50K. The -La2S3 may also be an oxysulfide of La10S14O2. Moreover, the ß .-La2S3 phase is transformed to Y -La2S3 ,which has a Th3P4 structure, at 1573 ± 100K. The melting point of Y -La2S3 is 2398 ± 30K where this temperature is similar to those of common refractory materials such as silica and alumina. Therefore, it can be predicted that y -La2S3 which has a high melting point and a thermodynamic stability due to the strong affinity of La for S, would have &high refractory character and chemical inertness in many molten metals. The y -La2S3, colored vivid faint yellow is stable up to 623K in air, where oxidation starts. y -La2S3 is frequently used as pigments for plastics and paints3. Furthermore, Y -La2S3 which is a semiconductor, is considered to be useful as a thermoelectric conversion materials, because it has a high Seebeck coefficient."

Jan 1, 2000

By Hongbo Zhao, Jun Wang, Wenqing Qin, Guanzhou Qiu

Jan 1, 2015