Search Documents

By Joseph Sofra

It has become increasingly evident that sustainable metals production in the 21st century requires producers to balance the needs of cost effective, high value production with that of responsible plant operation. This is becoming more difficult as lower grade and more complex feed materials, including recycled scrap and residues, are being processed to reduce production costs and decrease exposure to primary metal market fluctuations. One particular facet of the metals industry facing these challenges in the 21st century are copper producers, The recent steady decline in the copper price has seen the industry cut expenditure, tighten control on income streams and focus on high returns on capital investment. For these reasons copper producers are looking towards flexible technologies that can deliver high value products, with minimal environmental impact at low capital and low sustainable operating costs. Ausmelt's Top Submerged Lancing (TSL) technology for copper production is a low cost, proven technology for the processing of both primary and secondary copper materials. Both the smelting and converting operations introduce significant advantages in environmental performance, improved process efficiencies and high rates of metal recovery, Ausmelt has made significant gains in the past 4 years in establishing a strong market position for its copper technology, New installations in China, South Africa and India as well as existing operations in Zimbabwe and China have demonstrated its effectiveness. This paper reviews the application of Ausmelt Technology for both smelting and converting of primary and secondary sources, It discusses Ausmelt's design and implementation philosophy, and how this philosophy meshes with the needs of the end user.

Jan 1, 2003

By C. B. Solnordal, R. N. Taylor

"The heat transfer conditions on the outer side of a Sirosmelt lance have been determined using experimental measurements in combination with a mathematical model. By measuring the temperature distribution along the wall of an operating Sirosmelt lance, as well as the thickness of the slag layer on it, it was possible to use the model to determine both the heat transfer coefficient between the vessel contents and the lance, as well as the effective thermal conductivity of the slag layer. The effective thermal conductivity of the slag layer was found to be within the range 0.7-1.3 W.m-1. ºCl, which was in good agreement with measured values for magnetite. The outside heat transfer coefficient varied from 80 to ISO W.m-2. ºC1, which was smaller than quoted in the literature for metal/slag systems. The discrepancy was attributed to the high thermal resistance experienced between the lance wall and the slag layer, as well as the large quantities of combustion gases that envelop the lance tip and reduce convection and conduction from the melt to the lance. INTRODUCTIONThe Sirosmelt submerged combustion smelting process [1] utilizes top injection lances to deliver fuel and air into a metallurgical melt. To help prevent lance failure from attack by liquid slag, helical vane swirlers are used within the annular lance to impart swirl to the flowing air and enhance the heat transfer from the lance wall to the air. The swirlers thus cool the wall, and enable a frozen layer of slag to form on its outer surface. This solid layer ensures liquid slag cannot reach the lance surface, and the lance is protected.A mathematical model of the heat transfer processes associated with the lance has been developed, which combines heat balance equations with engineering correlations to predict the wall and cooling air temperature of the lance, as well as the air pressure distribution. An account of the model was given by Rankin et al. [2]. To further enhance the model and enable it to predict the thickness of slag accumulating on the lance, a detailed analysis of the heat flow through the slag layer commenced in 1992. By far the most complex aspect of the model, the flow of heat from the vessel contents to the outside of the lance was dependent on many factors, including:-"

Jan 1, 1996

By Patrick R. Taylor

A non-transferred arc thermal plasma assisted cyclone reactor has been designed, built and operated to evaluate its use in vitrification of wastes. Simulated waste (liquid, slurry or fine particulate) is injected near the plasma flame, where nearly instantaneous dehydration and calcination reactions happen. A non-transferred arc plasma torch was attached tangentially to the cyclone and is utilized as both an enthalpy source and to provide the gas velocities required to generate the cyclonic gas flow patterns. The closed top cyclone flow sends the solid particulates to the wall, where they are captured by a thin film of molten glass that is injected as a powder at a position lower in the reactor. The molten glass is then collected in a crucible. The feasibility of simulant injection directly into the flame zone and its effect on electrode lifetimes has been studied. Several candidate refractory systems have been evaluated for their suitability for extended use under the demanding conditions present in the cyclone reactor.

Jan 1, 2002

By Joseph Sofra

It has become increasingly evident that sustainable metals production in the 21" century requires producers to balance the needs of cost effective, high value production with that of responsible plant operation. This is becoming more difficult as lower grade and more complex feed materials, including recycled scrap and residues, arc being processed to reduce production costs and decrease exposure to primary metal market fluctuations. One particular facet of the metals industry facing these challenges in the 21 st century arc copper producers. The recent steady decline in the copper price has seen the industry cut expenditure, tighten control on income streams and focus on high returns on capital investment. For these reasons copper producers arc looking towards flexible technologies that can deliver high value products, with minimal environmental impact at low capital and low sustainable operating costs. Ausmelt's Top Submerged Lancing (TSL) technology for copper production is a low cost, proven technology for the processing of both primary and secondary copper materials. Both the smelting and converting operations introduce significant advantages in environmental performance, improved process efficiencies and high rates of metal recovery. Ausmelt has made significant gains in the past 4 years in establishing a strong market position for its copper technology. New installations in China, South Africa and India as well as existing operations in Zimbabwe and China have demonstrated its effectiveness. This paper reviews the application of Ausmelt Technology for both smelting and converting of primary and secondary sources. It discusses Ausmelt's design and implementation philosophy, and how this philosophy meshes with the needs of the end user.

Jan 1, 2003

By Yutaka Shiraishi

Two methods were developed to measure the viscosity of the slag from the glassy to the liquid states in an ascending temperature process. The first method employs rotating parallel plates within which is placed a solid cylindrical sample in line with a sphere. The second method uses a tube which is pushed into a sample held in a rotating crucible. Both methods were tested using standard glasses, including boron trioxide and NBS standard glass #711. The main difference between these two methods is in sample preparation. Comparative measurements between two methods were performed using a sodium boro-disilicate glass containing 5%mol of alumina. The results showed good agreement in the mid-range of glassy viscosities, 105 to 107 Pa.s. In the liquid state, there were no significant differences between the two methods.

Jan 1, 2003

By Kirsi M. Riihilahti

The oxidation characteristics of solid copper matte particles under simulated Kennecott-Outokumpu Flash Converting conditions are presented. The effects of feed matte grade, matte particle size, oxygen-to-matte mass ratio, oxygen content of the process gas and temperature on the particle oxidation rate, quality of conversion, particle size change and particle morphology were determined. The converting quality was highest (~68) with the 58% copper matte at 1100°C. At similar conditions, the 72% copper matte was more likely to produce copper oxides and leave unoxidized particles rather than directly produce sulfur dioxide at 1100°C, resulting in an average converting quality of 55. The quality of conversion was poorest for the 72% matte at 920°C (~45); the sulfur removal was extremely low even with a relatively high degree of oxidation. Fragmentation of the particles was significant in all cases with the 72% matte. A higher O2/matte .ratio and higher temperature, in general, resulted in increased fragmentation while oxygen enrichment had no significant effect. With the 58% matte, particle size was found to increase for the finest fractions rather than to decrease due to particle expansion.

Jan 1, 1998

By Neeraj Saxena, Madhu Huggahalli, Jerry Bednarski, Ken Grieshaber, David Stoffel

"The use of oxy-fuel burners in secondary aluminum melting applications offers several advantages over air-fuel burners including reduced fuel consumption, faster charge to tap times and lower NOx emissions. Their successful, safe and economical use in a furnace depends on several factors and considerations such as burner and flue placement, metal circulation, charge practices and the type of refractory used in the furnace.These factors required in the successful conversion of furnaces from air-fuel to oxy-fuel based burners are discussed in this paper. Critical parameters are identified and examined using computational fluid dynamics (CFD) simulations. Parameters are estimated via laboratory testing and validated through trials performed at commercial installations. Guidelines and a simplified approach to estimate a priori the economic impact of converting from air-fuel to oxy-fuel are presentedThe final products of this research are simplified and validated tools for modeling aluminum furnaces. These include improved heat and energy balance models and parameterized CFD solutions which provide rapid customization to individual furnace configurations. These tools provide field engineers with immediate and accurate predictions of performance, allowing for repeated precise scenario analyses."

Jan 1, 2001

By Susanne Pignolet-Brandom

Reflected light microscopy, and scanning electron microscope energy dispersive spectroscopic analysis and backscatter electron images were used to determine if a "slick dross" with undesirable handling properties has an assemblage of phases distinct from normal dross. This study has found that in the normal dross the most abundant lead phases are lead sulfide and lead metal and the most common copper phases are copper-iron sulfide and copper sulfide. In the slick dross, the most abundant copper phase is copper-lead sulfide and the most common lead phases are copper-lead sulfide and lead sulfide. The resulting mineralogical information has provided additional insight into the causes of the handling problem and the reaction mechanism for the formation of normal and slick dross

Jan 1, 1988

By Fiona J. Stevens McFadden, Gregory J. Hardie, Mark P. Taylor, William Uru

"Over 20 million tonnes of installed aluminium smelting capacity exists worldwide, with smelter energy con.sumption in the range 14-17 kWh/kg aluminium. In terms of the reduction cell technology itself, the lowest sustained energy consumption is just below 13DC kWh/kg, or 50% energy efficient.For 15 years Comalco Aluminium Ltd. in Australia has been engaged in developing and testing reduction cells that use a refractory hard cathode, composed of a TiBif carbon composite coating over a carbon cathode. This technology has the potential to reduce energy consumption significantly while simultaneously increasing the life of the cells, which is currently limited by wear rate of the conventional carbon cathodes used throughout the worldIntroductionThe successful development of an aluminium wettable cathode technology affords the opportunity to the cell designer and smelter operator to fundamentally change the physical operating characteristics of the Hall-Heroult process. With this revolutionary capability in hand, published papers and patents have indicated that the technology may be exploited in a wide variety of ways to improve the economic performance of aluminium smelting process. Comalco has been developing refractory hard cathode technology for more than 15 years and has been exploring a number of ways that the technology may be commercially applied in a smelter operation [l]."

Jan 1, 2000

By Y. Ono

In lightweight metal processing such as aluminum (AI) and magnesium (Mg), metal cleanliness is a crucial process parameter for refining, part manufacturing and recycling in order to obtain high quality parts and products. In this paper, techniques for cleanliness evaluation of molten AI and Mg using ultrasonic probes with clad steel buffer rods having high signal-to-noise ratio (SNR) are presented. Due to the high SNR of the ultrasonic probes used, backscattered ultrasonic signals from inclusions, which may be oxide films and/or particles, in molten Mg and those from silicon carbide particles, having an average size of 50f.Ull, added in molten AI are successfully detected with reflection configurations of pulse-echo and/or pitch-catch modes at an ultrasonic frequency of 10 MHz. In addition, relative cleanliness evaluation of molten Al and Mg is demonstrated. In order to establish the procedure and to investigate the optimum system configurations for cleanliness evaluation of molten metals, particle flow simulation system using water and polyvinyl chloride (PVC) particles has been constructed. Counting the number and measuring the size distribution of the PVC particles, having an average diameter of 128um, suspended in water with the PVC volume concentrations of 5ppm and 10ppm are performed with ultrasonic pitch-catch mode. The counted numbers of particles by the presented method and system have good agreement with the calculated results with a count error of less than 10% or two counts. Based on the results obtained with water simulation experiments, the prototype system for cleanliness evaluation of molten Mg by counting and sizing inclusions has been developed. Keywords: Ultrasound, Clad buffer rod, Molten metal, Aluminum, Magnesium, Inclusion detection, Cleanliness measurement, Counting, Sizing

Jan 1, 2003

By Jan A. Aune

The paper describes a number of electric furnace equipment modules especially developed or modified for slag furnace applications. Both the resulting design concept for a modern electric sulfide smelter and some of the changes in traditional process-concepts made possible are outlined.

Jan 1, 1983

By Jose Bengoa

Low metal prices and environmental restrictions are always a challenge for copper smelters operation and its productivity. Thus, in order to reduce production costs and control gas emissions, improvements of the Teniente Converter (CT) operation were made at 110 Smelter Plant of Southern Peru Copper Co" 110, Peru, and the main objective was to increase its capacity for smelting copper concentrates without affecting normal operation, The present work eorresponds to a recent study conducted during the normal industrial operation of the Teniente Converter in this plant and, it shows the effect of increasing air oxygen enrichment from 28 to 34% on its productivity. The results show an increasing of concentrate smelting rate from 800 to 1370 tpd and hence a notorious improving in copper production, and practically no effect on the refractory consumption. The increment of the concentrate throughput, increases also the SO2 concentration and the sulfuric acid production, showing the effort done by this operation in order to accomplish the environmental Peruvian regulation,

Jan 1, 2003

By C. J. Newman

Prior to 1995, the smelting process at the Kennecott Utah Copper Corporation (KUCC) smelter consisted of Noranda reactors and Pierce-Smith converters. In the consideration of expansion opportunities, the existing process did not lend itself to a program geared towards processing the total output of KUCC mining and milling operations. During 1989 and 1990, a number of smelting options were evaluated. The final selection was the Outokumpu flash smelting process, coupled with the new Kennecott-Outokumpu flash converting technology. Facilities were designed and installed to process 1:0 million tonnes per year of copper concentrate, with the ability to expand to 1.2 million tonnes per year. Following the shutdown of the smelter facility utilizing the Noranda technology in May 1995, the flash smelting, furnace commenced operation in June with the flash converting furnace startup following a few weeks later. The smelter has achieved design production targets and environmental goals. Current operating rates are at or above design rates for concentrate and matte processing. Emissions are lower than the permit levels and equate to less than 3.5 kg of SO2 per tonne of copper. This paper outlines the design, construction, startup and the first two years of operation of the modernized KUCC smelter.

Jan 1, 1998

By Kunwar Pal, S. K. Tyagi, A. K. Pandey

"This study deals with the performance evaluation, technical and environmental aspects of different cookstove models (NIRE-02, NIRE-03 & NIRE-04). These cookstove models were designed, fabricated and evaluated following Bureau of Indian Standards (BIS) and their performance was compared from technical and environmental points of views. The theoretical efficiencies of all the cookstove models are found to be in good agreement with the experimental one. Also, the overall performance of these models is found to be in the order of (NIRE-04 > NIRE-03 > NIRE-02) which is also observed to be much better than that of the traditional cookstoves being used by the people in most of the developing countries around the world. The CO2 emission reduction from these models is found to be between 2.0-3.0 tons per household annually which is ultimately in good agreement with the experimental values.IntroductionMore than 2.5 billion people around the world depends on the biomass based resources for cooking and heating applications which includes wood, cattle dung, charcoal and agriculture residue [1,2]. Generally, people of rural area cook their food on unvented open fire, which burn biomass fuel inefficiently besides it creates many thermal and environment pollution hazardous causing health problems in the women and girl children due to more exposure of emissions. Also the consumption of biomass is very high as compared to the fossil fuels due to the fact that the large population of the developing countries lives in the rural area than that of in the urban area. It is estimated that about 3% of the diseases are caused due to incomplete combustion of biomass, which results in the around 1.8 million premature death every year including around 0.9 million death under five year of their age [3,4].Ramanathan and Carmichael [5] recently found that the black carbon of unburned smoke is playing a major role in global warming. The emission factors for different combinations of fuel and stove tested in China for direct and indirect GHGs as well as other airborne pollutants such as, CO2, CO, CH4, TNMHC, N2O, SOx, NOx, TSP etc. for a typical set of operating parameters [6]. The improved biomass cookstove technology came into assistance which is technically feasible, socially reliable and economically viable [7, 8]. The improved biomass cookstove not only reduces pressure on the biomass resource, but also reduces the environmental pollution and also minimize the time required for collection of fuel wood [9, 10]. Sharma et al. [11] emphasized on the adoption and large-scale propagation of efficient stoves to improve the health of rural women and to reduce the consumption of firewood and environmental pollution."

Jan 1, 2014

By Yutaka Shiraishi

Two methods were developed to measure the viscosity of the slag from the glassy to the liquid states in an ascending temperature process. The first method employs rotating parallel plates within which is placed a solid cylindrical sample in line with a sphere. The second method uses a tube which is pushed into a sample held in a rotating crucible. Both methods were tested using standard glasses, including boron trioxide and NBS standard glass #711. The main difference between these two methods is in sample preparation. Comparative measurements between two methods were performed using a sodium boro-disilicate glass containing 5%mol of alumina. The results showed good agreement in the mid-range of glassy viscosities, 105 to to7 Pa.s. In the liquid state, there were no significant differences between the two methods.

Jan 1, 2003

By I. Barin

The thermodynamics of cyclone smelting of sulphidic copper ores is described using as example the production of copper matte with 75 wt % Cu. Equilibrium calcualtions and material and energy balances show that an increase in process temperature from 1600 K to 1900 K results in the extensive transfer of minor elements such as As, Sb, Bi, Pb, Zn,.... to the gas phase. A pilot plant for carrying out the cyclone smelting process is described. Calculations of material and heat transfer for the reaction of ZnS show that the smelting reactions of sulphides in the cyclone take place very rapidly at high temperatures. The dissociation of the sulphides with subsequent oxidation reactions in the gas phase plays an important part in. the process and is mainly controlled by heat transfer.

Jan 1, 1983

By Vince Newberry

Alcan Rolled Products at Oswego, New York, commissioned Recycle II during May of 1995. Recycle II is an advanced technology UBC recycling facility designed to meet the most stringent environmental standards enforced to date in the United States, particularly with respect to NO, and particulate emissions. This paper addresses the exacting requirements and strategies of Alcan's Recycle II project andThorpe Technologies' design considerations and solutions for the supply of environmentally favorable melting furnace and delacquering systems. The furnaces are equipped with low NOx regenerative burners and furnace pressure and hearth gas flow controls designed specifically for processing the hearth gases through baghouses. The delacquering system is a new generation Apros concurrent flow unit designed for low NOx emissions.

Jan 1, 1995

By J. A. Innes

"""The oxygen, next uniting with the carbon, sent up an ever-increasing stream of sparks and a voluminous white flame. Then followed a succession of mild explosions, throwing molten slags and splashes of metal high up into the air, the apparatus becoming a veritable volcano in a state of active eruption.""IntroductionHenry Bessemer F.R.S(An autobiography, 1905)Thank you Mr Chairman for the opportunity to speak: at this, the opening session of your International Symposium on the subject of ""Injection in Pyrometallurgy"". Judging from the list of papers to be presented over the next three days, the Symposium promises to provide a most valuable addition to our existing knowledge base in what is now an extremely active area of R&D investigations. Whilst we have obviously come a long way since Sir Henry Bessemer's pioneering experiments of the mid-19th century, there is still much for us to learn.Most importantly, the Symposium offers a further opportunity to acknowledge the many significant technical contributions made in this field by the Organising Committee's special guest, Professor Howard Worner - one of this country's most respected research leaders.When first approached to give this talk I had two areas of concern. Firstly, I was not entirely clear just what injection metallurgy was meant to cover. How should the overall scope of this particular subject be defined?My second concern related to Howard Worner himself - a man for whom I have the highest personal regard and who, in fact, played a most influential role in respect of shaping my own career. Having already spoken about Howard's achievements on earlier occasions, I wondered what I could sensibly add.Notwithstanding these personal reservations, I am delighted to be here with you this morning. If my thoughts on the meaning and scope of injection metallurgy appear to be slightly off-course, and if Howard should perhaps recognise some repetition in my remarks, then I hope I can be forgiven."

Jan 1, 1996

By Ph. Cauwe

This paper presents the experience that NESA and MECHIM have gained about recovery of non ferrous and precious metals from complex sulfide materials. Processed materials are from natural deposits or metallurgical by-products or residues. Roasting of these materials is closely related to the pyro or hydrometallurgical processes used downstream of the roasting. Conditions of a first step of roasting the SELECTIVE ROASTING, are analyzed and explained. The roasted products so obtained are characterised by an extended elimination of volatile sulfides (AS, Bi, Sb, Sn, Pb, Hg, ?? ) and are readily available for the pyrometallurgical recovery of non ferrous and precious metals. After the SELECTIVE ROASTING, thanks to. the high porosity obtained in the "selective calcine", the SULFATE ROASTING is per-formed in excellent conditions. Hydrometallurgical tests performed for the final calcine show a high recovery of non ferrous and precious? metals and require only simple and well known processes. Many experimental and commercial data are given.

Jan 1, 1983

By P. J. Mackey

Over the course of Dr. Robertson’s career, the ferrous and non-ferrous plants have seen enormous changes in technology and increases in plant capacity, essentially amounting to a “technological revolution”. In iron and steel, the “mega” blast furnace of some 6,000 m3 working volume is now standard (~10,000 tonnes (mt) of pig iron/day). Similar huge changes in process technology and plant size have occurred in the non-ferrous industry. As an example, the fuelfired reverberatory furnace, once the mainstay of the copper industry, has disappeared - replaced by large capacity flash and bath smelting technologies. The energy consumption per unit mass of metal produced has also been reduced considerably. Our understanding of the thermodynamics and mechanisms of metallurgical reactions, a field to which Dr. Robertson has significantly contributed, has made great strides. This paper reviews these changes with particular reference to the copper smelting industry, providing also comments on expected future trends.

Jan 1, 2014