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By Dennis J. Kemp

Laterite projects are found in the tropical and sub-tropical regions of the world. As a result severe meteorological situations accompany such projects, often in regions of high seismic activity and political uncertainty. Frequently, socio-economic development supported by political interest is a major driver for development, while environmental protection imposes numerous stresses on the project. This paper will review and examine the many social, environmental, technical and financial issues that a mining and extraction process is subject to during development. The options that must be evaluated will be discussed in the context of sustainable development. Issues of project standards and cultural impact through to long-term issues such as greenhouse gasses and climate change will be assessed in redirecting project environmental norms. Although a rationale for sustainable project can be developed many long- term uncertainties around issues remain. Keywords: sustainable development, communities, social issues, standards, energy, waste management, consultation, agreements

Jan 1, 2004

By Thomas Brynjulfsen, Merete Tangstad, Eli Ringdalen

Manganese ore fines cannot be added to the submerged arc furnace directly as they will prevent even gas flow through the burden. Low gas permeability in the burden will lower the degree of pre-reduction of ore subsequently increase the carbon and energy consumption of the process. In order to utilize manganese ore fines in the furnace, they are typically agglomerated into sinter. In this work, the melting and reduction properties of Gabonese sinter and Gabonese ore have been investigated in pilot scale experiments. Two experiments were conducted, one with 100% sinter as manganese source and one with 50/50 sinter and ore. Lime was used to achieve a charge basicity of 0.72 in both experiments. The composition of slag samples from the excavation of the furnace was established using EPMA(WDS), and the composition of the tapped slag and metal was found using XRF. It was found that while the coke-bed size would determine the tapped slag composition, the melting behavior of the Mn source would determine the mixing with lime.

Jan 1, 2014

By Fabio J. Esper, Wildor T. Hennies, Guillermo R. Martín-Cortés, Francisco R. Valenzuela-Díaz, Antonio J. Santana de Araujo, Maria G. Silva Valenzuela

Seeking to replace carbon-black as filler of rubber in the production of vulcanized goods, researchers from University of São Paulo have studied different materials types as minerals, vegetal or wastes agricultural and industry. Results of rubber composites filled with MA1 a waste of mineral treatment provided by Esper Industries are presented. MA1 was characterized through X-ray diffraction; Thermal analysis; Scanning Electronic Microscopy; and others laboratory methods. The composite and shaped masses were evaluated by these methods plus their mechanical properties such as tensile strength, elongation at break and hardness. Exceptional results were obtained in the mechanical properties evaluated, better than those obtained with the traditional carbon-black. Seeing the kind of material used as filler, it can conclude that the environmental benefit is present, as well as economic development, giving credibility to the use of these alternative material in replacement carbon black.

Jan 1, 2015

By T. T. Chen

The manganese oxide scales, consisting mainly of MnO2, characteristically occur in banded colloform structures which adhere to porous layers of PbSO4 and PbO2 that oxidized from the rolled Pb-0.7% Ag anodes. Hydrous Mn oxides, Mn3O4 and amorphous Mn oxides are believed to be also present. Tiny particles of gypsum, PbSO4, SrSO4 and AgCl are entrapped in the colloform masses. The gypsum originated from the Zn electrolyte; strontium carbonate was added to the ZnSO4 solution to control Pb, and silver originated from the anodes. Some of the colloform bands contain minor amounts of Pb, implying a limited degree of dissolution of the Pb during electrolysis. Other colloform bands incorporate trace amounts of Zn. Colloform structures permeated with silica gel are presumably caused by the high silica content of the electrolyte.

Jan 1, 2009

By Hirokazu Narita

The extractability for Pd(II) using MOTDA and DHS and their durability against a mixed solution of HNO3 and HCl was investigated by solvent extraction and FT-IR measurements. Both MOTDA and DHS selectively extracted Pd(II) over Pt(IV) from 0.75 M HNO32.25 M HCl solutions. The extraction rate of Pd(II) with MOTDA was much greater than that with DHS. In the durability test, the extraction percentage of Pd(II) and the FT-IR spectra were measured using MOTDA and DHS after stirring with 0.75 M HNO32.25 M HCl solutions. The extraction percentage of Pd(II) with MOTDA hardly changed during the two-month stirring; however, that with DHS decreased with an increase in the stirring time. The FT-IR spectra showed the sulfoxide formation by the oxidation of the sulfide in DHS, but not in MOTDA. Consequently, it was found that MOTDA is more durable than DHS.

Jan 1, 2006

By R. Dekkers

Non-metallic inclusions in liquid steel are mainly formed during killing. As far as these particles are not captured by the slag, they are found in the cast steel where they can deteriorate the mechanical properties. Inclusions may also disrupt the continuous casting process, affecting thus directly the quality of the steel and the production capacity. Steel pin samples from the Sidmar plant (Belgium) were taken in different steps of several ladle treatments and in the tundish. Also slab samples were studied. All samples concern the same type of low alloyed aluminium killed steel. The non-metallic inclusions were isolated from the steel matrix and investigated with scanning electron microscopy and energy dispersive spectrometry. The evolution of the non-metallic inclusions is described by their number, size, shape and elemental composition. The main non-metallic inclusions present are aluminium oxides and spinel type compounds.

Jan 1, 1999

By David Rees

Tomago Aluminium, a 400,OO tonnes per annum primary aluminium smelter in Australia, has installed Ozone for biological control of its process water. The system was designed in Australia by Ionics Watertec Engineering, whilst ANCO Australia monitors the water quality and provides technical support for the project. The motivation was initially to reduce operating costs, however investigations indicated that there were substantial environmental benefits to be achieved by the elimination of a part, or all of, the chemicals being used to control the system. Also the existing chemicals appeared to be losing their ability to control biological growth in the system, in particular, the legionella bacteria. Ozone water treatment commenced in January 1998 and after a short transition period has operated without chemical addition since. There appears to be no doubt that the biological control is effective, the clarity and purity of the water has improved and initial testing indicates that the corrosion control rate is acceptable, although some chemical corrosion control may be introduced after further testing around the total circuit to guarantee protection

Jan 1, 1999

By Nils Eivind Kamfjord, Mari K. Næss, Gabriella M. Tranell

"In oxidative ladle refining (OLR) of silicon, the metal surface is oxidized resulting in the formation of a condensed silica fume (SiO2). In the current work, industrial measurement campaigns were performed aiming to measure the fume generation during OLR. A thorough discussion of the possible mechanisms has been included in order to improve our understanding of the Si(1)-O2(g) system.The measurement campaigns were performed at the Elkem Salten plant in Norway. In addition to fume generation from OLR, the metal temperatures and ladle purge gas amount were recorded. The results of this work suggest that fume generation during OLR results from splashing of the metal and/or oxidation of the metal surface, with oxygen transport to the metal surface being the limiting factor. Other mechanisms of SiO2 formation were investigated, however insignificant.IntroductionOne of the main environmental and economical challenges facing the metallurgical industry is fugitive emissions of both materials and energy. In the production of metallurgical grade silicon (MG-Si), refining of the silicon generally takes place through an oxidative ladle treatment (purging with an air-O2 mixture). In the refining process, exposure of silicon to air results in the formation of condensed silica fumes (SiO2) – one of the main sources of fugitive emissions in silicon production plants. The oxidation of liquid silicon, as opposed to solid silicon, has not been widely studied and described in the literature [1], thus a thorough investigation of the oxidation mechanisms, and factors affecting the oxidation reaction rate are essential in order to deal with the problem. In the current work, the rate of liquid silicon oxidation has been studied through industrial measurements of fume generation from refining adles, where the purge gas rate and composition have been varied. The results from these measurements were discussed in light of existing models describing the liquid silicon oxidation kinetics."

Jan 1, 2011

By Minge Zhao, Yuandong Pei, Zhixing Zhao, Zejun Ma, Lili Ban

"Confocal scanning laser microscope (CSLM) has been applied to carry out the in-situ observation of melting and solidifying characteristics during iron ore sintering process, accompanied with TG-DSC test. It can be found that apparent Liquid phase forming temperature(LFT) and ending solidifying temperature(EST) is about 1190? and 1160?, respectively. Forming liquid phase during sintering process goes through four courses, these are shrinking, expanding, shrinking and expanding coexisting and expanding totally. For Yandi fine, the corresponding temperature of these four courses is about 1120-1160?, 1190-1196?, 1218-1220? and 1233-1270?, respectively. Although CAJ fine has more difficulty in forming initial liquid phase, but when liquid phase expands, it may have better fluidity and easier for liquid phase formation. Adding enough CaO, CAJ fine takes on high fluidity like Yandi fine, because liquid phase during sintering process is formed mainly by reaction between CaO and Fe2O3.IntroductionConfocal scanning laser microscope (CSLM for short) has been applied to carry out the in-situ observation of metallurgical phenomena, especially in steelmaking process. Recently, many researches on ironmaking process were conducted with CLSM. While for high temperature properties during sintering process, there are limited reports on in situ observation1-2). In this paper, melting and solidifying characteristics of iron ore were observed with CLSM under simulated sintering temperature, and high temperature properties of iron ore during sintering process was clarified based on the in situ observation results and TG-DSC research."

Jan 1, 2012

By D. C. Azubike

Wolframite (FeWO4) usually having cassiterite (SnO2) as a major impurity is a primary source of tungsten. Its direct reduction/carburisation with carbon in the temperature range 1000-1400°C, and with hydrogen at 600-900°C followed by carburisation with CO at 900°C are described. Depending on the conditions and reactants employed, Fe, Fe2W, B-Sn,WC, W2C, Fe3W3C and Fe6W6C are the products. Tin was found to inhibit the overall reduction and carburisation reactions significantly. The potential for either efficient separation of iron and tungsten or a one-stage production of an iron-based metal carbide composite is discussed.

Jan 1, 1992

By Daniel E. Groteke

This paper describes a new technology which allows aluminum drosses to be processed at the generating melting furnace to recover available metallic values. The systems, offered in both manual and automatic modes, are capable of processing quantities ranging from 15 to 200 lb. per cycle, and recovering up to 90% of the aluminum with a combination of agitation and chemical reactions. In the automatic mode, the separation of molten alloy and de-metallized dross is achieved in less than five minutes process time. The recovered alloy, of largely unchanged composition, may then be returned while at elevated temperature to the original melting furnace to achieve an additional saving of energy.

Jan 1, 2000

By M. E. Coleman, G. Money

"Clyde Materials Handling is an established customer-driven solutions provider, which utilizes its knowledge, expertise and technologies to transform the production processes of its customers, who operate in the ferrous and non-ferrous metals industries.With over 30 years experience in the process improvement industry, Clyde Materials Handling has helped their global customer base transform the way in which they operate their processes, which has enabled them to generate sustainable economic benefit and maintain their positions as leaders in their respective markets.Clyde Materials Handling has supported operators within the metals market by developing and deploying pneumatic conveying and pneumatic injection technologies. These environmentally supportive and sustainable solutions have been used to transport raw materials within operating facilities, from storage to silo, as well as injecting these materials directly into the heart of production processes.Clyde Materials Handling has worked closely with their customers, such as Codelco in Chile, where their pneumatic solutions have been used to inject a consistent, pulseless and accurate flow of copper concentrate into a bath smelter, which has helped to fuel the operational capacity, availability and productivity.This paper will discuss and highlight the ways in which pneumatic injection technologies, created by Clyde Materials Handling, and applied in partnership with their customers, have helped to improve the operational performance of the production processes of operators across the non-ferrous metals markets with specific reference to applications in the Peirce Smith Converter.Clyde Materials Handling has applications injecting Electronic Scraps, Dusts, Reverts, and other additives to the Peirce Smith Converter. They also have experience of modified PS Units used for Slag Cleaning. There experience with the Codelco Teniente Converter is also directly related to this area of operation."

Jan 1, 2009

By C. Dresen

This paper discussed the reaction kinetics of the reduction of industrial phosphate pellets for P4 production. In the reduction process of various phosphate ores, the following parameters were investigated: Diffusion of the phosphorus oxide and other gaseous products from the reaction mixture after having been reduced on the reductant (coke) surface. Influence of silica on reaction kinetics. Temperature influence. Influence of mineralogy and morphology (different ores). Particle size influence of silica and coke. Experiments were carried out in a vertical tube furnace with 2 ores, 2 types of silica and one type of coke. Selected experimental conditions simulated furnace conditions. The following conclusions could be made: Reaction rate increases with the addition of SiO2 into the pellet. The reaction rate increases above 1350°C (melting temperature of the slag). Mixing different ore types in the pellets leads to differences in reduction kinetics. Particle size of the coke particles influence reduction kinetics. The amount of slag formation is influenced by silica addition, coke size and temperature.

Jan 1, 2002

By Thomas Buenger

The Hamburg smelter of Norddeutsche Affinerie AG is situated near the city of Hamburg’s downtown and is therefore particularly subjected to fulfill environmental requirements according to the German legal regulations. Thus, investments related to increasing concentrate throughput are always linked to packages to enhance the emission status of the smelter. This connection between environmental protection and productivity enhancement should be explained by the example of the Peirce-Smith converter plant of the Hamburg smelter. Such outstanding investments can be demonstrated by the transition from scrap charging via boat from the front side to a fully automatic and completely sucked scrap charging system.

Jan 1, 2009

By Y. H. Liu

Several foaming aluminum samples of different density were prepared in a semi?industrial scale experimental system, Their properties such as the energy absorption characteristics, mechanical properties, heat conductivity and acoustical properties were measured. The results showed that the foaming aluminum with a density of 0.5 to 0.6 g/em3J has the best energy absorption and this makes it suitable as the ensuring bar of the automobiles and also as a cushion material for the engine. The foaming aluminum with a density of 0.25 to 0.4 g/em3 has the best acoustical properties and heat conductivity resistance, which is suitable for the door filling material, the ceiling and the partition or the car engine.

Jan 1, 2003

By Fuming Wang, Lifu Hu, Changrong Li, Ruipeng Pang

The solidification structure of 430 ferritic stainless steel has been calculated in the solidification process by using 3D-CAFE model under the condition of water cooling. The calculated results consistent with those obtained from experiment. Under watercooling condition, the solidification structure consists of chilled layer, columnar grain zone, transition zone and equiaxed grain zone

Jan 1, 2015

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 Adegbenjo Adewale Oladapo, Ibitoye Simeon Ademola, Ladiipo Olufemi Akinbiyi, Adegbola Adekunle Amos, Adeboje Taiwo Bode, Raji Fatai Olasunkanmi

The combined effects of the addition of Silicon (Si) as alloying element and low temperature annealing on the tensile properties of 70/30 brass with Nickel (Ni) and Iron (Fe) contaminants is investigated in this paper. Melts of cartridge brass were made to which 0, 0.5, 1, 2, 3 and 4 wt % of Si was added. These were sand cast into rods of 600 mm by 10 mm diameter and were thereafter machined into standard tensile test samples. Some of these samples were annealed in a muffle furnace at temperatures of 250, 300, 350, 400 and 450 oC respectively and the others were used as control. Subsequently, all the heat treated and non heat treated samples were subjected to tensile tests on a Hounsfield Extensometer and the load – extension plots retrieved were analyzed. Microstructural characterizations of the samples were carried out using Accu-Scope Optical Microscope. The results showed that cartridge brasses subjected to alloying and annealing treatments had improved tensile and yield strengths. However, the tensile properties were increased and maintained within acceptable limits at stress relieve annealing temperatures.

Jan 1, 2015

By Freddy Syvertsen

"During the past two years the Association of Norwegian Foundries in Norway has been running a project in evaluation of CAD/CAM systems for foundries.In this work we have had a closer look to the various steps from drawings to the finished castings. On this background we have made a specification of the special needs in the foundry process. The main content of this paper is a presentation of this specification.Some CAD/CAM sytems have been compared with the specification and a summary of the result is presented.In the project we have also had a closer look at some systems where we actually have tried the user interface and some of the possibilities in the systems. In this way we have gained a more detailed knowledge of the systems and we have also got some experience in NC-machining from the systems.IntroductionThe development of CAD/CAM systems has taken place with almost no interaction with the foundry business. This becomes clear when you are having a closer look at the systems. Most of them have not the possibility to describe the complex sculptured surfaces that is often found on castings. The people developing the software, have paid little or no attention to the problems arising when a geometry is going to be transformed for the casting process. Among the problems are the decision of where to place the parting line and to adjust the draft angle. These problems must be solved properly to be able to withdraw the model from the sandmould. In die casting the problems must be solved to be able to get the casting out of the die.In Norway some companies have been developing CAD/CAM systems for several years, with limited interest in foundry problems till 1983. To present the special foundry problems to them a specification of the needs was made that year. Another reason for making this specification, was to compare it with the CAD/CAM systems on the market (1).Design of castingsGeometry transferThe foundries in Norway are small units with almost no design of their own casting products. They are subcontractors receiving paper drawings and limited informations about the product from the mechanical industry both in Norway and in other European countries. This is going to change, and in the future the geometry will be transferred by magnetic tape or by a network of computers."

Jan 1, 1986

By Hongmin Zhu, Guihua Wang, Xiangsheng Wang

"The anode process of carbon electrode in fluoride melt was studied by voltammetry and chronoamperometry. Anode gases were analyzed by gas chromatography on-line during controlled-potential electrolysis. Two peaks were observed on the cyclic voltammograms. According to the results of gas chromatography, the first peak was corresponded to the discharge of residual oxide ions, with the formation of CO and CO2. Discharge of fluoride ions occurred at 4.1 V vs. Li+/Li, and leading to the anode effect. With the occurrence of anode effect, small amount of CF4 was detected. As the potential reached 4.5 V, CF4 and C2F6 gas evolution occurred, and the current increased to form the second peak.1.IntroductionIn the primary production of Aluminum and some rare earth metals like neodymium, a departure from normal cell operation known as anode effect results in the generation of perfluorocarbons (PFCs), which have high global warming potentials [1]. Owing to the pressure of environmental protection, considerable research has been carried out to clarify the mechanism of anode effect and PFC generation of industry and laboratory cells in the aluminum electrolysis system [2-9]. The common result on PFC generation is that the PFCs are emitted from Hall-Heroult cells only when they are on anode effect. In this article, we selected LiF, the main electrolyte for the neodymium electrolysis [10-11], to perform further investigation on the underlying kinetics of PFC generation and the nature of the reactions at the electrode.2. ExperimentalAll experiments were carried out in an alumina tube reactor, which was filled with high purity helium atmosphere. Spectrographic graphite crucibles were used, which played the dual role of molten fluoride container and the counter electrode. Lithium fluoride was analytical grade. The experiments were carried out at 900 °C."

Jan 1, 2011