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By S. N. Lekakh

Experimental work and thermodynamic simulations of cast iron refining were carried out using various additions of alkali and rare earth metals. The refining reactions for sulfur and oxygen removal were studied for melts treated with Mg, Ca, and Ce. The measured data and the results of the computer simulations were in agreement. Experimental kinetic data, together with the thermodynamic calculations, were used for optimization of the amount and sequence of the addition of nodulizers for ductile iron production.

Jan 1, 2009

By W. C. Chang

Phases and magnetic evolutions of melt spun Nd9.5(Fe1-xCox)85.5B5 (x=0, 0.05, 0.1 and 0.15), (Nd1-yLay)9.5Fe85.5B5 (y=0, 0.0.5, 0.1; and 0.15) and (Nd0.95La0.05)9.5(Fe1-zCrz)81.5B9 (z=0, 0.033, 0.067 and 0.1) nanocomposites: have been investigated. It was found that a. dilute Co substitution for Fe, x=0:05-0:15, in Nd9.5(Fe1-xCox) 85.5B5 improved not only Curie temperature but also the remanence and maximum energy product. Partial substitution of La for Nd in(Nd1-yLay)9.5Fe85.5B5 may suppress the grain growth of the materials during thermal treatment. Exchange coupling between the Nd2Fe14B and a-Fe was found: to increase with increasing La content. A dilute La-substitution, y=O. 10, has proven to decrease the optimum wheel speed required for preparing melt spun ribbons with better magnetic properties; Furthermore; a slight substitution of La for Nd in (Nd0.95La0.05)9.5(Fe1-xCrx)81.5B9 nanocomposite reduced the crystallization temperature of the over-quenched ribbons and led to the formation of a multiple phases mixture. Nevertheless, a dilute Cr addition increases the Tg of (Nd0.95La0.05)9.5(Fe1zCrz)81.5B9 and also suppresses the formation of the undesired (Nd,La)2Fe23B3 and Fe3B phases: Cr was found to play an important role in grain smoothening or magnetic separation which consequently increased the Hc of Cr-containing materials.

Jan 1, 1997

By Kenji Monden

A simple technique is presented to evaluate optical property of biomimetic microlens array (BMA) as an antireflective surface on a polydimethylsiloxane (PDMS) sheet. The integration of these structures is done by a thermoforming process. We have only UV-VIS spectrophotometer for optical evaluation apparatus. The transmittance of the sheet is measured with angled sample holder. The 50 deg. transmittance of 270nm pitch BMA on PDMS sheet increases from 87 to 92% after the moth-eye structure is introduced. The transmittance of 350nm pitch BMA on PDMS sheet increases from 87 to 96% after the moth-eye structure is introduced. The transmittance increases with increasing pitch of BMA. The results obtained using UV-VIS spectrophotometer with handmade sample holder.

Jan 1, 2015

By Robert W. Bartlett, Keith A. Prisbrey

"Natural biooxidation of shallow, refractory ore heaps, relying on gaseous oxygen diffusion from the heap surface is attractive because of its simplicity and potential low cost, especially without using a lined pad, which is possible if percolation of leachate through the heap is avoided. In this case, the excess oxidation enthalpy must be removed by water evaporation from within the wet ore heap, and the rising water vapor flux within it will impede the downward oxygen flux. An analysis of this process shows that for typical values of pyrite grades and limited temperature increases in the ore heap, the oxidation rate and penetration into the heap is reduced to values between about 30 percent and 50 percent of those obtained when leachate percolation occurs and water evaporation is not a significant mechanism of heat removal.IntroductionHeap biooxidation of refractory gold ores, needed as a pretreatment step to liberate the gold for subsequent extraction by leaching, requires large amounts of oxygen for the normal amounts of sulfide minerals that are typically present, one to two percent pyrite and/or arsenopyrite.The importance and potential limitations of oxygen transport into commercial ore heaps, which are much larger than encountered with column tests of ore and with pilot heaps, has been recognized111 • Commercial ore heaps using radial stacking conveyors are typically about nine meters high and may be 100 meters or more in lateral dimension. Three oxygen transport mechanisms have been identified and analyzed: ( 1) natural convection, which arises from an increase in buoyancy caused by the temperature rise and gas composition changes associated with the exothermic oxidation of the sulfide minerals within the ore heap, (2) forced air ventilation, using low pressure fans and air distribution pipes within the heap, and (3) diffusion of oxygen in the gas-filled void spaces within the ore heap driven by the oxygen concentration gradient from the surface of the heap to the mineral oxidation loci within it."

Jan 1, 1997

By Sandra M. Stash

An integrated copper production complex includes mining, milling and smelting facilities which are usually at or near a common site, and sized to complement one another in capacity. There may also be an electrolytic retlnery serving the complex, but not always totally dedicated to its production. Mines and mills without co-owned smelters are not usually considered integrated. The first marketable product of an integrated complex is blister, or in some cases electrolytically refined copper. The nature of integrated operation brings together all of the environmental issues associated with copper production, but currently operating and newly planned facilities are required to anticipate these issues and meet stringent regulations. Older complexes, however, may have legacies of 50 or more years of operation unencumbered by current levels of environmental strictures: nevertheless, they must be remediated. Using examples from closure and remediation of the mining and mineral processing facilities in the Upper Clark Fork River Basin of Montana, the authors review some of the problems encountered since CERCLA's1 enactment in 1980, and the solutions to those problems, bearing in mind that not all of the problems and solutions were technical. Much has been written about the mines of Butte -the "Richest Hill on Earth" as it was known in its day and the mills, smelters and refineries they spawned. These facilities comprised an archetype of the integrated copper complex: from ore to metal in facilities serving and depending on one another. Many great stories of technological innovations and business triumphs have been told about Butte and Anaconda's mining history and the place The Anaconda Company occupies in that history. However, relatively little has been written about the final days: 25 years during which the once-great complex was closed, and the remnants of past glories were remediated after nearly a century of operation. This paper offers some insights from the real world affecting similar complexes still operating, and, hopefully, lessons for others just starting down the path to final closure.

Jan 1, 2003

By Xingming Zhang, Huawei Zhang, Yanxiang Li

"A hybrid porous metal with nano-micro double scale pore size and regular-random bimodal porous structure has been fabricated by unidirectional solidification of a lotus-type alloy followed by dealloying treatment to the base alloy. The base alloy selected is a Cu-Mn binary alloy. The lotus-type porous Cu-Mn alloy with straight pores of several hundred micrometers in diameter was manufactured by unidirectional solidification with a mould casting process. Dealloying treatment was then done to the lotus-type porous structure of Cu-Mn alloy. The solid Cu-Mn alloy wall of the lotus-type porous structure was transformed to random porous structure of dozens to hundreds nanometers. The influence of corrosion parameters, such as the current and time in electrochemical corrosion, temperature and corrosion agent in chemical corrosion, on the nano-porous structure formed has been studied systematically.1. IntroductionA hybrid porous metal is a kind of cellular structure with different porous or cellular forms inside, which possesses special properties and can be applied in many fields as fuel cells, catalysis, sensors, etc. Several means have been developed to fabricate this kind of porous material [1-2]. In this paper, a novel process of Gasar plus dealloying is introduced to fabricate a new form of hybrid porous metal with nano-micro double size and regular-random bimodal structure.The Gasar process, also called the metal-gas eutectic directional solidification, that invented by Shapovalov [3] in Ukraine and now in USA some twenty years ago, is used to fabricate porous metals with regularly aligned pores basing on the solubility difference of a gaseous element in solid and liquid metal. Nakajima and his colleagues [4] in Japan studied this process further and called this kind of structure a lotus-type porous metal. They put more attention to various fabrication techniques and properties of lotus-type porous metals. Li heading a group [5-6] in P.R. China studied the mechanism of Gasar process and process controlling techniques. The Gasar pore structure and porosity can be controlled by processing parameters, and a regular Gasar structure with oriented pores distributing uniformly in the solid matrix can be obtained under optimized processing parameters."

Jan 1, 2014

By John R. Hugens

Modifications in the ALSCAN method of measuring hydrogen dissolved in liquid aluminum have made it possible to monitor the level of hydrogen dissolved in liquid copper. Measurements from the tundish show a correlation with eddy current readings from the continuously cast and rolled copper rod from the continuous casting and rolling system at Amarillo. The measurements also indicate that the copper in the tundish is supersaturated with hydrogen.

Jan 1, 1994

By Gus Van Weert

This paper describes the results of autoclave testwork where ferric nitrate was hydrolysed in the presence of certain cations and anions and the resulting hematite analyzed for foreign constituents. For the cations Zn++, Ni++, Cu++, and AI+++, selectivity factors of over 107 were found. Magnesium gave 3.106. These factors are calculated as Me/Fe in solution over Me/Fe in the hematite; Me representing the metal in ion added. As-a result of the testwork at Delft University of Technology, BUDELCO (the Netherlands electrolytic zinc producer) ran a series of ferric nitrate hydrolysis tests in the presence of 10 additional trace elements. Impurity levels were prejudiced on Me2 EPHA extraction of iron from their zinc circuit, followed by HNO3 stripping. Good selectivity against base metals was confirmed, but trace elements forming anions (As. Sb) and sulphate were incorporated in the hematite. These BUDELCO results are also presented.

Jan 1, 1995

By S. S. Chabot, S. E. James

A recent survey of CEOs from major steel companies worldwide revealed the importance of recycling zinc units from EAF dust, mill scale, blast furnace dust, and other zinc containing streams in their plants. Many processes were developed and installed in response to this challenge. The most successful approach involves the production of a crude zinc oxide and selling it to primary zinc producers to recover the metal value. The problem with this process is the high concentration of halides in the crude oxide. This type of material cannot be processed directly in an electrolytic zinc plant because of corrosion problems it will cause in electrolysis. In 1999, BRZ installed a zinc oxide receiving and washing plant to minimize the impact of halides to its circuit. A description of the washing plant and initial operating results are included.

Jan 1, 2000

By Jenifer S. Heath

Human health risk assessments can be used in mine permitting, and are frequently used to investigate areas of potential contamination and as a basis for remediation decision making. While some states and US Environmental Protection Agency (USEPA) Regions have their own guidance for the conduct of human health risk assessments, USEPA Headquarters guidance and the underlying science are changing and advancing rapidly. Even outside the US, USEPA guidance can affect risk assessment costs and conclusions, which in turn can affect cleanup costs or permitting options. This paper summarizes recent USEPA guidance and scientific evidence related to human health risk assessment for mining sites. This paper is designed for non-risk assessors, and so focuses on the potential applications and implications of the new guidance rather than the mathematical and theoretical details.

Jan 1, 1999

By Hideya Sato

Refractory wear caused by melts is one of the major determining factors for the interval of shut-down repair of the metallurgical furnaces in general. Calcium ferrite slag employed by M it subishi Continuous Copper Converter, shows hi& fluidity and corrosive characteristics against most of the refractories. In order to improve the corrosion resistance of the refractories, the mechanism of MgO-based refractory wear by the calcium ferrite slag was intensively studied. The dissolution behavior of the refractory into the molten slag and the penetration of the molten slag into the refractory were observed by crucible tests and newly developed oscillating furnace tests. It was found that the wear of MgO-based refractories by the calcium ferrite slag is mainly dominated by the internal structural failure caused by the penetration of CaO-Cu20 rich slag which is formed as a result of the preferential absorption of FeO, from original slag by the spinel of the refractory.

Jan 1, 1999

By Art Johnston

Gas handling at Magma Copper company's, San Manuel smelter receives process gas from a flash .smelting furnace and four copper converters. The major gas handling equip11lent consists of four electrostatic precipitators and a sulfuric acid plant. Process ,vessels in gas handling are, typically confined, spaces. Lethal gases, mechanical and chemical hazards, and the difficulty of rescue, should an accident occur, makes this area a must in the safety plan. The presence': of hazardous chemicals and explosive gases in process' vessels and piping are of major concern when repairs' are required. Proper job procedures are critical to prevent injury during repairs. This includes plant employees and contractors who are likely to be unfamiliar with the hazards ,involved. The safe operation of a gas handling operation must include the functions of operations employees on a daily basis. This includes a safe working environment and involvement of all employees in the safety program. If an injury does occur quick medical response is critical to prevent serious injury. Medical responders must be adequately trained and prepared to treat the injured person without becoming victims' themselves. The methods used at Magma Copper Company to deal with these safety problems are the focus of this presentation.

Jan 1, 1992

By James D. Navratil

The mineral magnetite, or synthetically prepared iron ferrite (FeO?Fe2O3), has been used to separate a wide variety of substances, such as dissolved metal species and particulate matter, from wastewater. In the absence of an external magnetic field, activated magnetite readily adsorbs numerous metal species including actinide elements. In the presence of the external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and submicron particles along with some complex and ion exchange sorption mechanisms. The removal of the magnetic field and use of a regenerating solution can easily regenerate the loaded magnetite. The process has recently been tested for the removal of other metal ions including cobalt and iron. This paper will review previous work on the use of iron oxides for wastewater treatment and discuss the development and potential of the magnetic filtration/sorption process for wastewater treatment applications in hydrometallurgy.

Jan 1, 2003

By Kenneth N. Pike

The need to comply with environmental regulations and increase production has resulted in modifications to the East Penn blast furnace operation. Changes made include furnace design modifications, closed loop water cooling with heat recovery, automated weighing and charging, automated tuyere punching, ammonia scrubbing of tail gases and improved metal and slag handling to minimize environmental impact. These changes have resulted in a marked increase in yearly production and compliance with many of the air, water and solid waste regulations.

Jan 1, 1990

By G. R. Adams, N. Y. Tang, N. Qiang

"Aluminum is the most important alloy addition to Zn baths for controlling the reaction kinetics between the steel substrate and molten Zn in continuous galvanizing operations. Due to the complexity of the Zn-Fe-Al ternary system, the measurement and control of effective bath Al remains a challenge for modem galvanizers. The successful development of Al sensors has made the real-time measurements of bath Al contents possible. To facilitate their application, a computer interface and a palm-size data logger have been developed by Cominco. Plant applications indicated that the sensor possessed sufficient accuracy for process monitoring and control. The working mechanism of the Al sensors and Cominco's development work is described, and the results of sensor applications are presented.IntroductionControl of bath Al content is critical in modem continuous galvanizing because it has a strong influence on coating structure and properties and the overall product quality. The control of effective bath Al content (Al in liquid solution) is particularly critical for galvannealing where a high bath Al content may lead to incomplete alloying during post annealing, and a low bath Al content may result in other operation problems, such as excessive bottom dross accumulation and difficulties in coating thickness control. The desirable accuracy of the Al control is within ±50 ppm of target levels. In principle, such an accuracy is achievable for modem chemical analysis facilities, such as atomic absorption photospectrometer (AAS) and induction-coupled plasma (ICP). However, a recent study carried out by the International Lead and Zinc Research Organization (ILZRO) indicated that such an accuracy is rarely achieved in the zinc and steel industries.(1)"

Jan 1, 1997

By Roberto Javier Santiago

The main properties of Calcium Carbide seem to be the grain size and the CaC2 content. This paper tries to describe the Calcium Carbide used in the South-American steel plants and how and where it is added.

Jan 1, 2006

By Leandro Voisin

A new pyrometallurgical treatment alternative is proposed for cleaning complex copper matte with high content of impurities in the copper smelting process, thus, in a suitable furnace, a given amount of pig iron will be added to the liquid complex matte with a matte grade between 65 and 75 % Cu under reducing condition and will produce three liquid phases of matte, copper-rich alloy and iron-rich alloy. Hence, in this study, firstly, a mass balance calculation was made on the basis of the reported data for the distribution ratios of the components among the three phases to define the optimum condition where most of the arsenic can be fixed in the less valuable liquid iron-rich alloy. By taking advantage of the high concentration of arsenic in the iron-rich alloy, the small volume alloy may be disposed in a yard, while the precious elements may be recovered effectively in the liquid copper-rich alloy and/or in the liquid matte. Secondly, laboratory-scale experiments were conducted to apply the proposed process to the matte produced from the slag-cleaning electrical furnace and the Teniente Converter of the Codelco-Norte smelter. The obtained results indicate that the proposed process for cleaning complex matte is promising.

Jan 1, 2006

By Juliana G. Gutierrez-Paredes, Gabriel Plascencia-Barrera, Fidel Reyes-Carmona

In Mexico, many tonnes of nickel from waste petrochemical catalysts are dumped every year. In order to recover all that nickel, a hydrometallurgical reactor was designed. This design was performed in a systematical fashion, which included the chemistry of the system under study, both a kinetic and mass transfer study, and finally the use of the RID function, to optimize the reactor size. It was found that the NiO leaching with sulfuric acid is well represented by a first order reaction. The mass transfer results are in good agreement with the experimental results, obtaining over 95% nickel extraction in both cases. A marketing study was also completed that determined that it is possible to make a good profit by processing this residue provided the capital cost was low.

Jan 1, 2000

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 D. S. Barr

The Freeport McMoRan chlorination circuit is comprised of four related processes: ore chlorination, gas scrubbing, chlorine supply and excess hypochlorite removal ("hypo kill"). Each of these processes are described, and related to the pertinent mineralogic components in the carbonaceous ore feed to the plant. The chlorination system in use at Jerritt Canyon to passivate forms of preg-robbing organic carbon has proven to be a cost effective and efficient means to recover gold from low sulfide carbonaceous refractory ores, where gold may not be specifically associated with either the sulfides or the carbon.

Jan 1, 1987