Search Documents

By Masafumi Maeda

Our aim in this project was to develop a new copper refining technology utilizing pyrometallurgical treatment and a raw materials preparation technique. In the recycling process; raw material is not an idealized concentrate of copper sulfide but is composed of various types of scrap, industrial wastes such as sludge, ash and slag, and municipal wastes. Since we cannot expect oxidation heat in this process as in sulfide smelting, organic materials are viewed as an alternative energy source. Quality of the copper produced is targeted as 99.99% and an intermediate grade will also be marketable. To benefit the plant, rare metals and other nonferrous metals will also be recovered The overall system is described in this paper, specific topics outlined and preliminary research presented. Current Japanese technology for recycling copper based materials is briefly reviewed.

Jan 1, 1995

By H. Walqui

Southern Peru Copper Corporation (SPCC) are currently modernizing the Ilo copper smelter. A single ISASMELT furnace will start smelting 1,200,000 tonnes per year of concentrate during the second half of 2006. The existing Peirce Smith converters are being upgraded for converting the matte to blister copper and a new acid plant and oxygen plant are being installed. Two new anode furnaces and a twin anode casting wheel have been installed in 2005 and commissioned in January 2006. The modernization project will ensure the smelter satisfies new environmental regulations due to come into force in January 2007. This paper summarises the background to the modernization project, describes the main design features of the new copper smelter and summarises progress on the smelter construction as of early 2006. This paper describes the genesis of the Ilo Smelter Modernization Project and describes in details the scope and current status of the project.

Jan 1, 2006

By John Sakala, Jeyapandian Sasikumar, Sydney Kwalela

The Isasmelt Furnace was commissioned in September 2006 with a concentrates treatment capacity of 850,000 tonnes per annum. However, the converter section became a bottleneck to the high throughput. Over 25% of the Isasmelt Furnace down time was attributed to lack of converter space. Factors that affected converter operations were low tuyere line campaign life (an average of 150 blows), high reverts generation, low conversion rates, and high converter cycle time. As a result of efforts carried out to improve converter operation, the average campaign life has increased to over 250 blows and reverts generation has been reduced from 22% of concentrate treated to 15%. Blister copper conversion rate has increased from 15 tonnes per hour to 19 tonnes per hour and blowing time per cycle has been reduced from 5.7 hours to 4.7 hours.

Jan 1, 2012

By Han Ilhan

This paper discusses and describes aspects of a cost effective and safe tailings impoundment selection. In light of the current low metal prices and recent tailings embankment failures around the world, it is becoming extremely more important to develop tailings impoundment design that balance cost efficiency with safety. The paper will present critical design components associated with a tailings impoundment which need to be addressed during the planning phase. Procedures for identifying various tailings impoundment alternatives, and evaluation and selection of alternatives are presented.

Jan 1, 1999

By S. Goto, S. Yamashita, K. Hata

"The average consumption of zinc dust for purification of zinc leaching solution is more than 25 kg per tonne of electrolytic zinc. Authors proposed to remove impurities in zinc leaching solution by electrolysis instead of cementation by zinc dust. The effects of copper and arsenic on electrodeposition of cobalt in zinc sulfate solution were examined fundamentally using a potentiostat. It is observed that cobalt is easily deposited on a cathode at potentials under -480mV with arsenic. Mesh cathodes of stainless steel and lead anodes were used in a small electrolytic cell and the electrolyte was circulated through 'the electrodes during the electrolysis. The effect of electrolyte circulating rate , pH, cell temperature, current density, and concentration of copper and arsenious ions on removal of cobalt were studied. Removal of Cd and Ni are also examined.IntroductionCobalt is difficult to remove from a zinc leaching solution by a simple cementation reaction using zinc dust. However, it is easily precipitated by zinc dust with co-addition of arsenious or stibinous oxide and copper ion in practical operations(I), (2), (3). The consumption of zinc dust for purification is 16-152 kg per tonne of electrolytic zinc and 65% of this zinc dust consumption is used for cobalt purification. The average retention time for purification of cobalt is 4.5 hours (1). A more economical process for purification is desired instead of zinc dust. The mechanism of this acceleration effect of copper and arsenious oxide on removal of cobalt are explained by the authorsas follows; a galvanic cell is formed between zinc dust and copper which is precipitated firstly, and cobalt is reduced on copper as Co-As alloy by this galvanic current(2). This assumption was confirmed in experiments using a galvanic cell with a membrane( 4). The following galvanic reactions occur between zinc dust and copper precipitate; on copper cathode,2H+ + 2e -= Hz(g)2Coz+ + 2HAs02 + 6H ++ 10e -= 2CoAs + 4HzOand on zinc anode,Zn = Zn = 2+ 2e –This galvanic current becomes almost zero in a zinc sulfate solution which includes only cobalt and no arsenious oxide, and cobalt is weakly deposited on a copper cathode. Cobalt deposition requiers a high degree of cathodic polarization. However, the galvanic current flows almost constantly in an electrolyte, which includes arsenious oxide, and the cathode potential is kept at about -500mV. Cobalt is precipitated as Co-As on the cathode.The authors assumed that cobalt may be removed by electrolysis at a very low current density instead of zinc dust and the following experiments were carried out. In the first part of this paper, the fundamental experiments using a potentiostat on the behaviour of cobalt in zinc sulfate solution are described. In the second part, the results of the electrolysis are reported. Cobalt is removed by a new type of an electrolytic cell, which was desigoed to <Iccelerate the rate of deposition of cobalt. The removal of cadmium and nickel in a solution which includes cobalt and arsenic are also examined."

Jan 1, 1997

By John M. Boyle

The use of high vacuum mercury retort recovery as a safe and effective means of removing mercury from mercury hazardous waste solids rendering them non-hazardous and recovering mercury suitable for recycling.

Jan 1, 1995

By P. Chris Pistorius

"Use of coke in blast furnace ironmaking is the main origin of carbon dioxide emissions from integrated steelmaking. Use of pre-reduced iron feedstocks would reduce the coke rate and, if pre-reduction were carried out with natural gas, would decrease the overall carbon intensity of ironmaking. Blast furnace productivity would also increase, because the blast volume per unit of hot metal would decrease. This paper shows that these trends can be predicted quantitatively, by using a conceptually simple Rist-style blast furnace mass and energy balance, assuming furnace productivity to be limited by the tuyere gas flow rate. Such predictions would assist in optimizing the choice of the degree of reduction and relative amount of pre-reduced blast furnace feed.IntroductionSteelmaking is responsible for some 5% of world CO2 emissions, at a rate of approximately 1.9 tonnes of CO2 per tonne of cast steel [1]. In integrated steelmaking, the ultimate source of most of the CO2 emissions is coke, the indispensible (and expensive) fuel and reductant for blast furnaces. There are several research programs underway worldwide which seek to lower the carbon intensity of ironmaking; one of the largest is the European ULCOS program [2], in which the main proposed change to blast furnace ironmaking is to scrub CO2 from the furnace off-gas (for possible sequestration), recycling the remaining gas to the furnace. To limit the recycling nitrogen load, oxygen rather than air is used to combust coke.A conceptually simpler approach is to charge prereduced feed (direct-reduced iron) to the blast furnace. This approach has been used for some two decades at the AK Steel Middletown plant, where some 200 kg of direct-reduced iron (DRI) is charged per tonne of hot metal [3]. The Middletown blast furnace has exceptionally high productivity (rate of iron production relative to the furnace hearth area), simply because less coke is required per ton of hot metal if part of the feed is already metallic. Midrex [4] has provided some quantitative predictions of the implications of DRI use in the blast furnace, stating that for every 10% of Fe in the feedstock that is in metallic form, the fuel requirement decreases by 7% and the productivity increases by 8%."

Jan 1, 2012

By Tuomas Hirsi

The world’s first large scale modular solvent extraction plants have been delivered by Outotec. The first of these is now in operation and has proven that the VSF®X technology can deliver the excellent performance of the Outotec VSF® solvent extraction process. Modular delivery allows site work to be minimized and the manufacturing done in a controlled environment, allowing for serial production manufacturing benefits. Container based delivery was found to be a highly efficient way of utilizing the standardized transportation methods on a global scale. Site work with modular units was found to be efficient and highly predictable. In this paper, we present the first successful Outotec VSF®X deliveries and discuss the benefits of the modular delivery and design compared to the standard solvent extraction installation’s delivery. The process performance of the VSF®X is also discussed with experiences from the first industrial reference presented.

By N. Bazzanella

The hydrogen desorption kinetics of pure and Nb-doped magnesium hydride film samples was investigated by using a Sievert-type apparatus. The overall activation energy and the reaction order controlling desorption are (141±5) kJ mol-1H and n 4 for Mg hydride and (51±5) kJ mol-1H and n 1 for Nb-doped (5% at) Mg hydride indicating that, in the doped sample, hydrogen desorption is controlled by the H migration in transformed h-Mg layers. Structural analysis performed by X-Ray Diffraction (XRD) and Extended X-Ray Absorption Fine Structure spectroscopy (EXAFS) show that the catalytic effect of the Nb dopant is connected with the formation of NbH0.89 nanoclusters dispersed in the Mg hydride matrix. It is suggested that the catalysis process is also connected to the presence of Mg-Nb hydride interfaces where the transfer of H atoms preferentially occurs by connecting h-Mg grains and by the role of the MgH2-NbH0.89 interface as preferential site for the dissociation of the hydride phase.

Jan 1, 2006

By R. Abel F.

In 1997, Ventanas electrolytic refinery expanded its production capacity from 215,000 to 325,000 metric tons per year. This increase in capacity has involved the treatment of anodes with different impurity contents, changing the operational strategy of the plant. On the other hand, the increasing necessity to accomplish environment conservation rules and quality assuring requirements, has led the plant operation and administration to compete in an advantageous way. The present work describes the results obtained in the startup and in the operation of the ENAMI Ventanas electrolytic refinery expansion, and shows the difficulties which have been faced in the processing of anodes of increasing complexity, in a competitive market and with environment and quality restrictions.

Jan 1, 1999

By Raymond F. Dalton

Despite the ready availability of numerous zinc sources, the process of solvent extraction- electrowinning (SX-EW) has as yet found little favour in the zinc industry. It is suggested that this is largely due to the previous lack of availability of suitable selective reagents having the particular features required to enable them to fit in to a solvent extraction-electrowinning based process for zinc, particularly with regard to strength and selectivity for zinc over iron. This paper describes work on the development of new selective extractants for the recovery of zinc from both sulfate and chloride aqueous solutions and suggests how they might be integrated into new zinc processes.

Jan 1, 1994

By Pertti Pekkala

Outokumpu has 25 years of experience in the SX area. The development of the solvent extraction plants responds to an ever increasing demand for lower operational costs wd for adaptability to process disturbances with minimized risks. In this paper the features of the VSF ("Vertical Smooth Flow") SX technology are described, such as the separated pumping and mixing, the homogenous gentle mixing, the droplet coalescence and the ultra pure settling. A major advantage of the mixing technology is the high stage efficiency of above 99 per cent. The connection between this and some features of the settler front section is clarified. The present design of VSF plants is based on experience of existing operations at, for example, Zaldivar, Radomiro, Morenci, Kokkola and Harjavalta. These production plants cover a unit capacity range of 60 to 3,600 m3/h expressed as a total flow. It is evident that there are no restrictive factors to increase the total flow up to 5,000-6,000 m3/h by introducing the VSF technology. The copper SX technology has a long history reflecting many individual features of the separate copper SX plants. Still it is necessary to verify all actual running parameters by pilot tests taking into account impurities, chemicals used etc. The design of SX plants is not only about the delivery of equipment but also a process concept, and it is best tailor-made and adapted to specific local requirements.

Jan 1, 1999

By Florian Kongoli

The liquidus surface of multicomponent slags is an important parameter in various smelting and converting processes. It helps not only to optimize the slag, chemistry of current processes and their fluxing strategies, but also to determine the availability of new slags for more advanced technologies. In a series of our previous publications, the liquidus surface of some multicomponent iron oxide slags has been quantified at several constant oxygen potentials and the effect of the latter, ignored until that moment, was quantified along with the effect of some minor components. In this work, the liquidus surface of some iron oxide slags is quantified at constant CO2/CO ratios. This is a new convenient way for the quantitative description of the slag liquidus surface and the effect of several fluxes, especially in those processes such as slag solidification, where oxygen potential changes continuously. This type of diagram also describes more dynamically the effect of oxygen potential, clarifies the relation between CO2/CO ratio and oxygen potential in terms of the liquidus surface, which is not widely understood by metallurgist today, and reduces the gap between laboratory work and industrial experience.

Jan 1, 2002

By J. M. Floyd

"Top submerged lance furnace developments started in CSIRO in the early 1970s and was given the name Sirosmelt. In the early work the technology was developed for tin smelting and processing tin slags but once a small pilot plant was established other slag processing applications were soon recognised and evaluated for various copper, nickel, zinc and cobalt-containing slags. The process was tried for copper smelting and converting, which was proven in the small pilot plant in 1978. In the same year the first commercial application of the technology was established for the recovery of tin from slags at Associated Tin Smelters, Sydney. Work on lead smelting was initiated by the CSIRO team in the late 1970s and laboratory work led to pilot plant trials by Mount Isa Mines.In the second decade of the technology the focus of development became commercial acceptance of the technology through marketing, development and application by Ausmelt and Mount Isa Mines; the former commercialising and developing the technology for a wide range of applications, while the latter concentrated on its own commercial needs of copper and lead smelting. This decade saw a number of commercial plants built in Australia, with considerable interest becoming evident from other parts of the world. Towards the end of this decade Mount Isa also entered into the business of marketing of the technology through rights dating to the joint work with CSIRO in the late 1970s.So far, after five years, the third decade of the technology has been characterised by diversification of applications of the technology to areas outside the non-ferrous and precious metals production industry. The waste processing and recycle industry and the iron and steel industry have recognised that the top submerged lancing system is a new type of reactor with many significant features which provide new opportunities for processing a range of materials under good environmental controls in a cost effective manner.I hope this audience will excuse my boldness in talking about the third decade of the technology when we are only half way through! I am aiming in this paper to not only talk about the past, but to try illustrate the future directions which I envision."

Jan 1, 1996

By Daniel A. Norrgran

Grinding ball fragments discharging from SAG mills and ball mills causes extreme wear to downstream processing equipment. These ball fragments, recirculating in a milling circuit, will cause excessive wear to sumps, pumps, hydrocyclones, and interconnecting piping. A magnetic separation system to remove grinding ball fragments from the mill discharge has been developed and successfully applied in the milling circuit. This magnetic separation system - termed Trammel Magnet - was first applied at the Escondida copper concentrator in Chile. The Trommel Magnet consists of an arc of permanent magnets mounted at the discharge end&apos; of the tommel screen. The magnetic arc attracts the ball fragments and removes them from the process stream. This retrofitted magnetic separation system removed 126 metric tons of ball fragments from the circulating load of a. single ball mill in the initial 24 hour period. The mill has since stabilized and the magnetic separator is currently removing 7 metric tons per day of ball fragments. The retrofit of the Trommel Magnet has: 1. Extended the pumpp life and the hydrocyclone life approximately 300 percent. 2. Provided a 5 percent increase in the throughput of the mills by removing grinding ball fragments that contribute very little to the grinding process. Variations of the Trommel Magnet have also been developed for removing grinding ball fragments directly from the mill discharge without the use of a trommel screen. In each case, permanent magnets are used to collect the ball fragments from the mill discharge stream prior to reporting to the sump. These other systems have been designed and fabricated for in-plant test work.

Jan 1, 1999

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By A. P. Paiva

Studies focused on the recovery of precious metals by solvent extraction have recently increased. either to devise suitable solvents or to clarify the involved extraction mechanisms and kinetics. In this work, a comparison of the performance exhibited by triphenylphosphine (TPP), bis-(penty1thio)-ethane (BPTE) and triisobutylphosphine sulfide CI"I&apos;BPS) in the extraction of silver from acidic chloride media is carried out. Extraction and stripping isotherms involving the three extractants are presented together with the results obtained on the selectivity of silver extraction against high contents of iron, copper and lead. Attempts to clarify the mechanism of silver extraction by TIBPS were performed by studying the distribution coefficient dependence on ligand and chloride concentrations. The effect of temperature on extraction and stripping is also considered. The interfacial tension for the system, measured with different concentrations of extractant in the organic phase, is analysed.

Jan 1, 1994

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 Sun-Hee Cheong

This study sought to produce L(+)-calcium lactate using precipitated calcium carbonate as a starter culture composite of lactic acid bacteria in lactic acid fermentation. Specifically, precipitated calcium carbonate was synthesized by reacting calcium hydroxide with sodium carbonate in the previous study by the authors. Synthetic precipitated calcium carbonate was then used as the calcium source of lactic acid bacteria during the fermentation process. In general, precipitated calcium carbonate has low absorption rate in the human body. On the other hand, calcium lactate has high absorption rate; it is commonly used in food and drug industries as calcium additives in various foods such as cookies, beverages, bread, sauces, powdered milk, and fruit juice. Calcium lactate has two racemates, e.g., L(+)-lactate and D(-)-lactate. In particular, L(+)-lactate is known to be more soluble than D(-)-lactate and generally produced from lactose by homo-fermentative lactic acid bacteria such as Lactococcus spp., Lactobacillus plantarum, Lactobacillus casei, Lactobacillus curvatus, and Pediococcus spp. Thus, the characteristics of the pertinent lactic acid bacteria and optimal condition such as temperature, pH, precipitated calcium carbonate addition rate, and content of fermentation for increasing formation yield and purity were investigated. The findings suggested the possibility of manufacturing L(+)-calcium lactate using precipitated calcium carbonate as a calcium source with high value-added instead of commercial calcium lactate.

Jan 1, 2006

By P. E. Donaldson

Since 1992, Falconbridge has made available to the international copper industry, Kidd Creek&apos;s licensed refinery process technology under the name of the Kidd Process. This has resulted in the supply and installation of permanent cathodes and associated product handling equipment to refineries in Canada, the United States, South Korea, Chile and Mexico. These installations accommodate both electrorefining and electrowinning processes. The growth and industrial acceptance of the Kidd Process has generated technical advancements in the areas of product random sampling, corrugation, marking, labeling, product tracking and data acquisition. In a different area, the expanded development of custom materials processing at Kidd created a need to advance technologically. The process-related problem of high nickel concentrations in refinery electrolyte compromised an increase in current density to >300 A/m2. The need for nickel removal resulted in Kidd Creek&apos;s newly developed Nickel Recovery System. The effective and economical extraction of nickel, along with reduced antimony and bismuth levels, reduces bleed stream volumes and/or neutralization costs and simultaneously produces a marketable nickel carbonate product.

Jan 1, 1999