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By Thomas Niehoff

"Oxyfuel combustion systems are state of the art for many melting operations. Airfuel systems have been stepwise modified to oxygen enrichment, oxygen lancing and oxyfuel. Every change of the melting process will have consequences with regards to emissions and energy usage. The uniqueness of many operations requires unique skills to resolve potential issues. This paper will give some examples of how airfuel systems can successfully be converted to oxyfuel.IntroductionOxyfuel technology – meaning the combustion of fossil fuels such as natural gas, oil or coal with technical oxygen instead of air for industrial melting or heating processes is widely used in many industries these days. Even though oxygen production, storage and handling has been state of the art for decades other opinions exist. Often oxyfuel is regarded with fear and potential hazards like: “Oxygen makes the process too hot.”, “Oxygen will melt away the refractory.”, Liquid oxygen is dangerous.”, “Oxygen will cause explosions.”, ……etc.Typically a more detailed discussion about a specific industrial process and how oxygen can be applied in a safe and economic way the seeming issues go away."

Jan 1, 2010

By P. M. Tyroler

At INCO's Copper Cliff Nickel Refinery, nickel is extracted by using the INCO Pressure Carbonyl (IPC) process. The resulting IPC residue containing copper, nickel, cobalt, iron, sulphur, precious metals, selenium and tellurium is further processed at a hydrometallurgical plant. This plant treats approximately fifty metric tons per day of IPC residue. The components of the feed are separated in a number of steps and a precious metals concentrate, nickel-cobalt carbonate, a selenium-tellurium intermediate and copper cathodes are produced. An iron-arsenic waste stream is also produced and discarded to tailings. The hydrometallurgical processes include pres- sure leaching, cementation, precipitation, thickening, filtration and electrowinning. This paper describes in detail the individual steps of the flowsheet.

Jan 1, 1988

By Leijun Li, M. M. Mahapatra

"A three-dimensional finite element model with moving heat source was developed for pulsed-laser powder deposition (PLPD) process. Experiments were conducted to study the repair of superalloy components using the PLPD process. During the experiments, IN 625 powder was deposited on a superalloy substrate similar to IN 738. The process was modeled using three-dimensional finite element analysis. Element birth and death technique was used in the finite element model for simulating the deposition of powder layer on the substrate. A moving distributed heat source was used in the thermal model for realistic simulation of the process. Temperature dependent thermal material properties including enthalpy were used for the powder and the substrate in the transient thermal analyses. The fusion zones and peak temperature distributions of the deposits were predicted from the transient thermal analyses.IntroductionPoor weldability is a critical issue of superalloy repairing. The microstructural directionality of the superalloy components are disrupted when repaired by the fusion welding processes. Currently there is no widely accepted method to economically and reliably repair directionally solidified superalloys components. Pulsed laser powder deposition process (PLPD) is a promising repairing technique as the substrate is not severely affected by the heat source.In this study PLPD technology is used as the tool for superalloy repairing. In most of the land based turbine engines the directionally solidified nickel based superalloy similar to IN 738 [1] is used as the bucket material. The turbine engine blade tips are subjected to a combination of extreme operating conditions and corrosive environment. The tip of the nickel based turbine engine blades can be repaired using IN 625 material as suggested in the literature [1-2]. IN 625 is considered to be ductile and strong enough for the purpose of Ni based turbine engine blade tip repair[1-2]. During the present PLPD investigation, IN 625 powder was used as the deposit material on an experimental super alloy substrate similar to IN 738 superalloy used as the cast superalloy for the turbine engine blades."

Jan 1, 2012

By B. C. F1intoff, R. G. Bradburn, E. Groiss

"The concentrator at Brenda Mines Ltd. treats a copper - molybdenum porphyry ore with current head grades of 0.185% Cu and 0.036% Mo. The consistently low head grades provided the driving force to explore methods of improving plant productivity. Computer based process control was recognized as one means of addressing this objective. Over the period from 1974 to 1982 a control system evolved which now extends to every area of the mill. Control strategies are built on elements of classical, modern and rudimentary expert control. In addition, the control system has often served as a catalyst for other technological developments. The economic returns associated with the system are very significant and it has played an important role in the mine's survival in times of poor metal markets. This paper presents an overview of the computer control system at Brenda.PreambleOne can scarcely avoid picking up a trade magazine or newspaper today without seeing some reference to technology and its potential impact on North American business. _A recurring theme is the need to apply technology to raise our standard of plant automation in the manufacturing and process industries. The general thesis of these articles has been concisely captured in the mutually exclusive set:AUTOMATE or EMIGRATE or EVAPORATEProcess control is one form of automation that has been successfully exploited by various sectors of these industries. In minerals and metal processing the wide scale adoption of process control technology has, until recently, been largely limited to a few companies - most of whom have a history in the area dating back to the early 1970’s. However, there is definitely an increased and much broader interest in process control as a technology which can improve performance, productivity and profit.The economic hardships that were visited on the mining industry in the early 1980's are not easily forgotten. It is the authors' conviction that the mining industry must move to implement proven technology, in particular process control, in order to be well postured for the next (inevitable) down cycle.In pursuing the technical and trade literature, one can discover a number of example of the successful utilization of process control systems in mining and related applications. In the text which follows, the authors describe the process control efforts undertaken in the Brenda Mines Ltd. concentrator."

Jan 1, 1989

By P. A. Metz

The Fairbanks mining district has produced in excess of 7.5 million troy ounces of placer gold and 250,000 troy ounces of lode gold since gold was discovered in the area in 1902. The Fairbanks mining district is in the northwestern part of the Yukon-Tanana Upland Schist Terrane, an area of approximately 240,000 square km that has produced in excess of 21 million troy ounces of placer gold. All lode gold production from the terrane has been from the Fairbanks mining district, and all of this production has come from high-grade gold-quartz polymetallic sulfide veins. Gold grains in the vein systems range in size from several microns to several millimeters. The veins are localized in a complex metamorphic rock assemblage which includes greenstones and felsic metavolcanic and volcaniclastic rocks, meta-exhalatives and metasediments. Gold occurs in the metamorphic host rocks in association with arsenopyrite and arsenic-antimony sulfides which occur in lenses and disseminations within the host rock. Gold grains occurring in the metamorphic host rocks range. in size from sub-micron to a few microns in diameter.

Jan 1, 1987

By Janene Barter

Telfer Gold Mine treats both gold/copper oxide and sulfide ores in a remote location in the Great Sandy Desert, Western Australia. Currently, the oxide gold ore is treated in a conventional CIL circuit by blending the low and high grade copper ores to minimise cyanide consumption and allow smooth operation. The sulfide ore is treated through a flotation circuit to produce pyrite and copper concentrates. The pyrite concentrate is treated in the CIL. Copper concentrate is stockpiled and sold to a smelter for further processing. In recent times, as the depth of the pit has increased the copper head grade has also increased, to the point where the ore was becoming uneconomical to treat. In addition, it was desirable to reduce the amount of cyanide reporting to the tails dam both from an environmental and economical viewpoint. Newcrest Mining Limited engaged GRD Minproc Limited to evaluated a process to reduce the amount of cyanide entering the tail dam with consideration given to copper recovery. From this investigation, the Sulfidisation, Acidification, Recycle and Thickening (SART) process was selected. A detailed testwork program for SART was undertaken with the objective to design and construct a SART plant at Telfer. This paper outlines how the SART process was chosen and summarises the testwork that led to the design of the SART plant. It also touches on some of the important issues for designing this type of process.

Jan 1, 1998

By Alex Meystel, Diran Apelian

"In this paper, an outline is given for a theory of intelligent control (IC) of manufacturing processes (MP) based upon what all of them have in common: all MP's can be represented as distributed networks of sequential/parallel elementary ""lumped"" models; all elementary models are organized by definite input-output conditions, and by the set of constraints; all elementary models incorporate not only well defined physical knowledge, but also assumed physical knowledge, expert knowledge, expected knowledge to be obtained during the process from sensors, etc. This creates a hierarchy of elementary controllers coordinated by local coordinators of different levels up to a global coordinator. The latter verifies the adequacy of MP by using a holistic image of the process: depictogram. The structure of knowledge based controller is introduced, and the analytical/linguistic tools of control are presented. The concept entails a number of perspectives which are discussed in the conclusions.1. IntroductionIt is becoming increasingly clear to those of us in Engineering and Technology oriented fields that the so called ""service industries"" do not create wealth. Moreover, it is now accepted that manufacturing is the key to the creation of wealth from a socio-economic point of view. This appreciation of the importance of manufacturing is reflected by the transformations we are seeing in our factories, as well as the changes in both curricula and research activities of our universities. Though we find these changes to be in the right direction, there is yet much more to be done to advance the frontiers of manufacturing and materials processing as we approach the third rnillenium."

Jan 1, 1988

By B. Sereda

As it is known the creation and development of new titanic alloys has been problematic up to now. They can be used in aircraft and vehicle construction, shipbuilding and as materials for keeping static loadings in high-temperature environments. In this work the synthesis of various titan aluminides is investigated. Mathematical model of structurization process was done. On the base of retrieved model the mechanisms of structurization in systems Ti + Al and Ti + 3Al was determined. Experimental researches were done at two different modes: burning and thermal spontaneous ignition. The method of retrieving compacted products combusted in SHS conditions (SHS-compacting) was used to gain these intermetallic compounds. The physical and thermal characteristics of technological process and their influence on structurization, homogeneity of structure and porosity of titan aluminides have been simulated and researched. It is established that the SHS-compactizing technology is fully capable of supervising the process of structurizations with the whole complex of advantages and can be applied for receiving qualitative titan aluminides with the set of chemical-physical properties.

Jan 1, 2010

By Norihiko Fukatsu

In order to use effectively the previously reported new sensing system for hydrogen and oxygen potentials in molten copper, the criteria of the potentials for getting sound castings have been determined in the laboratory experiment. The copper melt equilibrated with a given hydrogen and an oxygen potential was rapidly quenched in the crucible. The relations between the holding potentials and the gas porosity in the solidified sample were investigated by measuring the density of the sample and microscopic observations. It was found that the defects of the gas porosity became the maximum at the potentials where the dissolved amount of hydrogen and oxygen was in the mole ratio 2: I. The samples having the density more than 99% of the theoretical value were obtained in the higher oxygen and lower hydrogen potential region or in the lower oxygen and higher hydrogen potential region. The criteria thus determined were examined by comparing with the measured potentials in the practical easting machine. In tough-pitch copper casting, the problem due to gas porosity was found to be serious when the hydrogen potential increased. In the oxygen-free copper casting, the evolution of hydrogen was found not avoided. The gas porosity in the casting, however, was found eliminated when the oxygen potential was kept at a low value.

Jan 1, 2003

By A. V. Kuznetsov, R. I. Kamkin, V. M. Paretskiy, A. Y. Mamaev, V. P. Bystrov, A. S. Vernigora

"Vanukov furnace technology is an efficient, proven pyrometallurgical injection technology, used extensively in Russia and Kazakhstan for a number of different applications. The technology was most widely adopted for processing copper sulfide concentrates for matte in smelters in Norilsk, Revda (Russia) and Balkhash (Kazakhstan). The following applications also were developed and tested at industrial scale: treatment of sulfide lead and lead-zinc concentrates, laterite nickel ore, production of cast iron, treatment of antimony gold-containing ores, and municipal solid waste. In this paper, current experience of Vanukov furnace application to these technologies is described with a number of general development trends and new areas of application.IntroductionAt the present time, the Vanukov process, developed at the Moscow State Institute of Steel and Alloys at the Department of metallurgy of non-ferrous, rare and noble metals with collaboration with other research organizations, is a highly efficient technological solution for processing different kinds of raw materials. The process was invented by Professor Andrey Vladimirovich Vanukov, whose research work began in 1949. From 1956 to 1975 test runs of the technology were carried out at the smelters in Norilsk and Balkhash. In 1976 a pilot Vanukov furnace was built in Ryazan. Furnace designs was modified to suit the various test programs. A major objective of each experiment was the determination of optimal working conditions for processing different types of raw materials such as copper, copper-nickel, copper-zinc, lead or pyrite concentrates, and materials containing secondary lead and zinc. After the death of Andrey Vladimirovich Vanukov in 1986, this technology and furnaces based on the technology were named after him: “Vanukov process” and “Vanukov furnace”. Today, the following furnaces based on Vanukov technology are either working or were tested at semi-industrial scale: three in Norilsk, two in Revda (Russia) and two in Balkhash (Kazakhstan) for treatment of copper sulfide concentrates for matte, one in Orsk (Russia) for processing laterite nickel ore, one in the Buruktal plant (Russia) for antimony gold-containing ores for antimony oxide sublimates and gold-containing metallic antimony, and one in China for processing sulfide lead and lead-zinc concentrates for production of black lead and zinc-containing sublimates."

Jan 1, 2011

By R. D. Osmanson

A series of batch roasting tests was performed on minus 1/2 inch gold bearing refractory samples from the Gold Acres deposit, and 67 select particles were polished and the sulfide alterations were examined microscopically. The suite of specimens represents two hour batch roast treatments at 600°C, 700°C, 725°C, 750°c, 800°C, and 900°C. Auriferous pyrites were found to alter sequencially to pyrrhotite, magnetite and finally to hematite. It was found that the decrease in cyanidation extraction with high temperature roasting is likely due to the increas ing stability of magnetite and more crystalline hematite, and the decrease in porosity with these phases which occlude the gold. Gold has been noted to occur very early in the mineralizing sequence, with gold being found in quartz and in clay/carbonate rock matrix. No gold was found in the two pyrite phases, but numerous gold grains were found in pyrrhotite after pyrite and in subsequent iron oxides. Gold mineralization had apparently ended by the time base metals were introduced into the deposit.

Jan 1, 1987

By R. W. Lawrence

A high rate biological reduction technology has been developed to provide low cost hydrogen sulphide for various uses in water treatment and metallurgical processes. Commercial operations produce sulphide safely at a fraction of the cost of chemical sulphide. The biologically produced H2S is used for treatment of acid wastewater and selective metal recovery whereby metals present in wastewater streams are recovered in high grade metal sulphide concentrates that are sold to smelters. The combination of biological H2S production and selective metal recovery is currently marketed under the process name BioSulphide-Thiopaq. The process can be applied on a stand-alone basis or in conjunction with a conventional lime water treatment. Process advantages include: reduced lime treatment costs, reduced volume of waste sludge free of toxic metals leading to reduced long term environmental liabilities, selective recovery of metals and, in some cases, net profit from water treatment achieved through the sale of metal concentrates. Three case studies are presented to provide examples water treatment and metal recovery: the Caribou Mine, New Brunswick; the Phelps Dodge Bisbee operations, Arizona; and Falconbridge?s Raglan nickel mine in Quebec. A fourth case study is presented to highlight environmental control for treatment of ARD in the Leadville mining district of Colorado. Process flowsheets, capital and operating costs are presented for the four case studies

Jan 1, 2003

By Stephan Mulch, Christian His, Patrick M. Stephan, Thibault Champion

"When fuel costs increase dramatically, waste to energy (WTE) conversion technologies become a good alternative to produce energy. The potential energy available in domestic wastes, in developed countries, could be upwards of 4% of their total energy needs. Due to low energy recovery and low level of treated domestic wastes in many countries, the energy coming from waste is generally less than 0.5% of the country needs.Domestic waste incineration can convert heat to electricity for industry and housing and allow waste volume reduction in countries where land fills are a scarce resource.There is a request to improve existing combustion technology by increasing energy recovery with better heat transfer in the boiler and also by increasing lining durability with more resistant materials and technologies.The knowledge of corrosion phenomena and material performance allows Saint-Gobain Group to develop and propose high performance refractory lining solutions.IntroductionThe interest in alternative energy has been growing dramatically in the two last decades due to several combined factors, such as global energy demand, fuels prices evolution (e.g. crude oil, Figure 1) or environmental and geopolitics factors"

Jan 1, 2008

By Jefferson Caponero

The tire is an expressive component of Municipal Solid Waste, manly when its occupied volume is considered. Its treatment by pyrolysis stands for a list of advantages, such as: landfill releasing and a production of a high quality fuel. The exploitation of new natural resources is becoming more difficult each day, basically due to the environmental damages caused by this type of activity. This work presents a study on the thermal behaviour of Brazilian tires using thermogravimetric analysis and differential thermal analysis, in order to optimise the pyrolysis process of tires. Samples of I to 2 mm were investigated at atmospheres of nitrogen, argon, oxygen and mixtures of these gases at temperatures up to 1273K, under heating rates between 1 to 50 Klmin . The results showed that the behaviour of each sample is related to both the atmosphere composition and the heating rate.

Jan 1, 2001

By Doug Halbe

?Many are called, but few are chosen.? The biblical adage applies not only to life, but also to hydrometallurgical processes. There have been, in the past, many outstanding successes with new processes ? and also some dismal failures. What are the odds of success for a new process? When there have been problems, why? What can you do to make sure these problems don?t occur with your process? What effect will a slow startup have on project economics? How do financial institutions ? the people who loan your company money for the project ? feel about new processes and why? Is it possible to predict or estimate the time required to reach design parameters?and if so, how do you sell this estimate to management ? and financial institutions? Probably most important ? when do you start thinking about the answers to these questions?

Jan 1, 2003

By A. Raraz

The optimization of the plutonium electrorefining process has been studied on the basis of modeling and model materials. The plutonium electrorefining process has been reviewed and the basics of the electrorefining process with molten salts as electrolytes and under forced convection has been presented. The definition of the problem in plutonium electrorefining has been related to three factors and this research has addressed these three factors to provide an insight to this process. The hydrodynamic factor gives information on the behavior of the mechanically stirred system. The chemical stability and solidification factor shows the interactions among the components of the electrorefining cell. The electrochemical factor is oriented to study the efficiency of the electrorefining process on the basis of limiting current density, stirring rate and configuration cell. As a result of this study the optimization of plutonium electrorefining implies mainly a re-design of the cell.

Jan 1, 1995

By J. Sjöblom

New copper and nickel processes, flash converting and DON, direct high-grade nickel matte smelting, have been developed in order to replace the conventional and not so environmentally friendly PS-converting process. With a laboratory scale laminar-flow furnace the combustion reactions of sulfidic feed particles can be investigated under simulated flash smelting conditions. In the present study, finely ground and screened feed fractions of a copper matte and a nickel matte were flash oxidized in a laminar-flow furnace. The experiments were carried out using 20, 21 vol% and 75 vol% O2 in nitrogen, at temperatures 1100 and 1300 °C and reaction zone length of 7.5-16 cm. The samples were quenched in a water film after a specified reaction time. The matte particle reactions were stopped after short residence time intervals in order to obtain a better understanding of the reaction mechanisms. Chemical analysis was used to determine oxidation degree, and optical and scanning electron microscope combined with energy dispersive analysis was used for characterization of the reacted particles. On the basis of the experimental results the reactivity of the mattes is discussed and possible reaction and dust formation mechanisms are considered.

Jan 1, 1999

By Guozhu Ye

"One of the most essential problems associated with the treatment of EAF dust is its high content of halogens. For most thermal processes for zinc recovery, such as the plasma processes with a zinc condenser, the halides in the gas stream will form a dross phase that results in a low zinc yield. For those with zinc oxide as main product, such as Waelz oxides, the high halogen content in the product implies a great degradation of the product quality and the product can only be sold at a low price. Further processing of zinc oxide with high halogen content either by pyrometallurgical or hydrometallurgical processes will also result in process problems.This paper will review the pre- and post-treatment alternatives for halogen removal based on the comprehensive characterization work that has been carried out at MEFOS and the preliminary experimental results.The experimental results show that chlorine and fluorine content could be reduced to 450 ppm and 50 ppm respectively by selective sulfation, and to about 200 ppm by soda leaching. Selective sulfation of zinc oxide in the EAF dust will also be discussed."

Jan 1, 2000

By E. Açma

In this study, the production of Cu, Co, and magnetic iron oxide from the ancient copper, slags, located in Küre-Turkey, is investigated. In the process under development, fayalitic slags containing 1% Cu, 0.43% Co are reduced in a D.C. arc furnace with coke or graphite additions. A metallic alloy, consisting of 3.8% Cu, 3.3% Co, 2.1% S, and the rest being Ice, is produced by granulation of the liquid metal. About 85% recoveries of Cu and C:o are achieved by hot sulfuric acid leaching of these granules followed by H2S precipitation. The, production of magnetic iron oxide is possible from the discarded leach solution, loaded v:ith FeS04, by using a method with geothite precipitation, dehydration, controlled reduction, and re-oxidation steps. The magnetic oxides produced have 20 m2Jg surface area, 1:8.3 aspect ratio, and the coercivity of 330-380 Oersted.

Jan 1, 1993

By Vladyslav M. Sokolov

The cost effective and environmentally friendly recycling technology was developed and tested. It enables utilization of the fine nickel-base superalloy scrap in a form of heavily oxidized scarfing granulates. The process of granulates generation was discussed in details. Their properties were investigated. The results of literature search showed anticipated sufficient improvement of the properties of cast iron by its alloying with the elements from the scarfing granulates. The novel alloying approach is based on the two stage reduction operation. Firstly thegranulates were partially reduced in a solid state by their exposure with powdery carbon at the range of 1550 ? 1700°C. Then the gotten product was efficiently introduced into liquid iron since it has a form of fine natural agglomerates for arranging the optimal conditions for reduction of the granulates. The thermodynamic evaluation demonstrates higher reduction efficiency of carbon and silicon dissolved in iron than of the same elements in a form of the separate phases. The considered process partially provides itself by energy since the reaction of reduction of the chromium oxide by silicon dissolved in liquid iron has exothermal character. The mostly complete extraction of Ni was received. The sufficient reclamation of Cr was gotten at the same time.

Jan 1, 2006