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By James D. Navratil

Ferrites have been used to separate a wide range of substances such as dissolved metal species, particulate matter, and organic and biological materials; they have been used almost exclusively for metal waste treatment applications. The versatility of the ferrite waste treatment technique is evident in the wide variety of application methods. Furthermore, ferrites can be used to remove selected impurities in feed solutions containing metal products requiring purification. A brief overview of ferrite properties and recent applications for metal recovery and waste processing will be presented.

Jan 1, 1990

By Levent Özmen

Colemanite is a mineral containing varying amount of boron that is found in abundance in Turkey. It has a good possibility to be used as a flux in iron and steel industry. In this study a review of the use of colemanite, as a flux agent in steel production has been carried out and various related aspects such as its influence in metal-slag reactions, solubility of lime and magnesia in the slag are discussed along its performance in several points of views including its technical and environmental usage characteristics. Positive and negative factors of using this material as a flux are also underlined.

Jan 1, 2006

By Manuel Pérez-Tello

A mathematical model to represent the expansion and fragmentation of copper matte particles oxidized under flash converting conditions is presented. The model assumes the particles to be initially nonporous, have a constant mass prior to fragmentation, and travel at a constant velocity throughout the reaction chamber. The model requires the specification of five parameters: the particle expansion rate, a fragmentation diameter factor, a fragmentation size distribution parameter, and the fractions of the finest and the coarsest particles in the feed that undergo fragmentation. The model predictions show good agreement with experimental data collected in a laboratory flash converting furnace over a wide range of experimental conditions. The evolution of the size distribution of the particles along the reactor length was computed, and the model parameters were correlated with the experimental operating variables. Model predictions indicate that particle residence time is an important factor in the generation of dust. The presence of two maxima in the particle density function may be attributed to turbulent conditions prevailing in the furnace, which cause particles to follow very different trajectories within the furnace even if they are injected at the same location.

Jan 1, 2006

By J. H. de. Visser

The transfer of molten metal in smelting or refining operations is typically performed in open trough-type launders that are constructed of either water-cooled copper troughs or refractory lined steel jackets. This transfer can be either continuous or batch. Batch operations transfer metal through an open launder. The uncovered launder has many operational and environmental drawbacks. In order to improve workplace hygiene, designs have evolved toward ventilated launder covers that .are connected to secondary exhaust systems that use negative pressure under the cover removing fume and hot gases to secondary fume control devices. In smelting operations, a variety of covers have been employed which insulate the launder and contain the fumes and also provide additional heat along the length of the launder through a series of premix or inspiration-type burners that add combustion products to the normal fume load in the launder. Cover designs have proven to be inadequate in that hinged unventilated covers hinder convenient access while heated ventilated covers are costly to maintain. Covers that employ refractory bricks and overhead enclosure-type exhaust hoods have been somewhat successful, but restrict operator movement and require large volumes of exhaust air. An example is given of a cover and off-gas system for launders that is designed to provide superior insulation and heating capabilities, as well: as better control of the fume gases-and ease of maintenance. The cover system must maintain the balance between maintaining launder heat and fume removal. The construction of the covers must be able to withstand high internal temperatures and maintain its structural properties.

Jan 1, 1999

By K. B. Dotson

A common international safety and health management system was developed. Analysis of selected major safety and health management systems from around the world was conducted. Functional elements of selected systems were grouped to identify common elements and key differences. Common elements were subjected to qualitative judgments of equivalency and then reconciled. With few exceptions, differing elements were revised to achieve cultural neutrality. The resulting 98 system elements were organized according to the NOSA numbering and title scheme. System summaries were produced in Spanish and English. A pre-implementation self-assessment evaluated conformance in three distinct cultures. The consensus 98 element system was internally named the BHP Copper Five Star Safety System Performance Management Guidelines. Development of a common system within an organization with international operations can enhance the ability of the staff function to share resources, programs and subsystem improvements and thereby increasingly protect workers. Common systems can increase the level of management support by demonstrating increased compatibility of the safety and health management function with traditional business objectives. Safety professionals, industrial and occupational hygienists, business managers and the safety and health of workers will benefit from further development and articulation of common systems for safety and health management.

Jan 1, 1999

By Jorge A. S. Tenório, Pedro F. A. Prado, Denise C. R. Espinosa

There has been an increasing push to develop environmentally sound recycling processes of electronic waste (WEEE), including end-of-life photovoltaic modules, to reclaim materials such as silver which is both valuable and pollutant to human health and wildlife. However, process sustainability and economic feasibility of PV panels recycling is strongly tied to the materials separation step, which currently presents challenges due to use of high temperature treatments and strongly acidic solutions. A method using an easily accessible solvent — isopropanol— dissolved the silicone-based encapsulant of crystalline silicon PV modules in 2 days at room temperature, separating the module into semiconductor wafer, glass, ribbon and backsheet.

Mar 1, 2017

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 equipment 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 adeqliately 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 E. M. Alcântara

This paper describes some aspects about the relationship between copper electrorefining addition reagents and the hydrogen in the cathode. The conditions of electrorefining were studied by factorial design methods. The advantages of this technique are reduction in the number of tests, well organized experiments; improvement in productivity and reliability of results. The dosage of the two main addition agents, glue and thiourea, were varied simultaneously and compared with the hydrogen content in the cathode. The influence of these factors, as well their interactions were analyzed by statistical methods denominated ANOVA (Analysis of Variance). The increase of thiourea quantities, within of levels studied, influenced significantly at 95% confidence in the hydrogen content in copper cathode.

Jan 1, 1999

By Toru Taniguchi

In the Mitsubishi smelting furnace, copper concentrate, silica sand and water granulated slag from the converting furnace are injected through the process lances, together with oxygen enriched air, into the melt. Because bath smelting is used, the rates of particles/melt and gas/melt reactions are high enough and therefore tine grinding of the solid materials is' not necessary. Among these reactions, the dissolution rate of silica sand is the slowest and limits the overall reactions in the smelting furnace. Information on the dissolution rate of silica sand plays an important role for design of a new furnace. Theoretical calculations of the dissolution rate .of silica particles have been reported elsewhere. The authors conducted cold model experiments and could verify the calculation. In this paper, the dependence of dissolution rates of particles on the gas blowing rate, particle size and solid penetration depth in the bath is discussed.

Jan 1, 2002

By Ashish D. Patel, Ramesh S. Minisandram

"Vacuum Arc Remelting (VAR) is the final and, hence, critical melting step for the production of a sound, segregation-free ingot for the manufacture of alloys used in rotating components in aircraft engines. A mathematical model for this process has been developed by the Specialty Metal Processing Consortium (SMPC). The model predicts temperature distribution in the solidifying ingot, flow in the molten metal pool, and the electromagnetic field in the ingot. These predictions may be used to estimate the effect of melting parameters on the pool profile in the ingot. In this paper, typical pool shapes and flow fields during VAR of Alloy 718 and Ti-6Al-4V are presented. The differences in the pool profile are primarily due to vastly different melting conditions. The model predictions are compared to the observed pool shapes from industrial-size VAR ingots.1. IntroductionVacuum Arc Remelting (VAR) is a process in which an electrode is melted in vacuum by the heat from a DC electric arc. Metal droplets from the electrode fall into the molten metal pool, which solidifies in a water-cooled copper crucible to form the ingot, as shown in Figure I. The ingot obtained from VAR is sound, and has superior cleanliness and chemical homogeneity. Hence, the process is the final melting process for most nickel-base superalloys and titanium alloys used in the manufacture of critical rotating components (discs & blades) of aircraft engines. Modeling of this process provides an insight into the effect of melting parameters on the molten metal pool in the solidifying ingot, which is a key first step in process optimization and defect prevention. In this paper, typical pool shapes, both measured and predicted, for VAR of Alloy 718 and Ti-6Al-4Vare presented. Alloy 718 is the most common VAR-processed nickel-base superalloy; whereas Ti-6Al-4V is the ''workhorse"" alloy for titanium-based alloys."

Jan 1, 2004

By J. R. Addison

Commissioned in September 1987, the Phelps Dodge Morenci, Inc. (PDMI) Central Electrowinning (EW) Tankhouse bas undergone two major expansions in its eleven-year history. A third tankhouse renovation, which began in November 1998, entails complete conversion of the 548-cell facility from a copper starter sheet based operation to Mt. Isa Process stainless steel mother blank technology. This paper outlines the operating history of the Central EW Tankhouse and reviews the conversion process, the rationale that led PDMI to undertake this project, and describes various design optimizations which have been implemented during the conversion.

Jan 1, 1999

By V. Bojarevics, K. Pericleous

"A number of different methods have been developed for noncontact electromagnetic treatment of liquid metal and to investigate the melting/solidification processes. Applying AC magnetic field in terrestrial conditions, along with the buoyancy and thermo-capillary forces, results in turbulent flow. The use of a homogenous DC magnetic field allows damping both of the turbulence and the large scale flow at different rates leading to surprising results at some stages. The dynamic interaction of the turbulent flow with the oscillating interface needs to be accounted if it is required to levitate liquid metal of up to few kilograms without the contact to container walls. At the high values of magnetic field some oscillation modes are damped quickly, while others are modified with a considerable shift of the oscillating droplet frequencies and the damping constants from the non-magnetic case. Numerical models are used to investigate behavior of liquid metal suspended in high DC magnetic fields providing microgravity-like conditions with laminar viscosity and heat transfer to the surroundings.IntroductionSince the early Electro Magnetic (EM) levitation experiments [1] in AC magnetic field it became apparent that the levitated liquid metal is prone to oscillation and instability. The EM and electrostatic levitation experiments with liquid metal droplets show difficulties related to confinement stability and a need for complex correction functions to establish a correlation between the measurements and the droplet material properties [2,3]. Intense internal fluid flow is visually observed, apparently being in the turbulent regime for earthbound conditions."

Jan 1, 2012

By Olli Järvinen

The capacity of the Outokumpu Pori refinery is today about 125 000 mt in 1998. The anode slime amount is about 700-800 mt. The copper is removed with pressure leaching. Selenium roasting is done with the gas roasting. The doré smelting in the furnace is done with the tilting rotating converter with oxy-fuel burner (TROP). Doré anodes are treated in the silver electrolysis. Gold is recovered from the gold mud with the quick hydrochloric acid leaching process. The important point in the leaching is to get into contact the solid copper with the oxygen and liquid. Outokumpu has an efficient agitator for this purpose. The GLS-agitator (GLS=gas, liquid and solid) is powerful for mixing oxygen, liquid and solid together. The current production in Pori plant is 40000 kg of silver, 5000 kg gold, 40000 kg of selenium and one hundred kilograms of platinum-palladium concentrate.

Jan 1, 2000

By C. K. Gupta

Electrometallurgical processes have a definite place in the extraction technology of rare earth metals and alloys. Some of the advantages of the molten-salt electrometallurgical processes include fast electrode reaction, providing accurately controlled large amount of energy to a relatively small reactor volume, negligible over voltage, simplicity of operation, and possibility of accomplishing continuous or semicontinuoue operations. This paper provides a vivid account of the theoretical and practical aspects of electrometallurgical processes for the production and processing of some of the rare earth metals and alloys. Reference has been drawn to the work reported on electrometallurgical processes as applied to the preparation of lanthanum, cerium and misch metal from author's laboratory.

Jan 1, 1992

By J. M. Tourre

1995 have seen a continuation of a positive trend in the Rare Earth industry The availability of a greater diversity of Raw Material has brought additional flexibility to the Producers permitting better economics China remains the major raw material source; Chinese concentrate producers have increased capacity in 1995 (Baotou, Sichuan, etc) China's role in the Rare Earth industry will continue to evolve; the acquisition of a majority equity position by San Huan/CNNC will have a significant impact on both the Rare Earth and Magnet markets Chinese producers are increasing the quality of their products and realize their true values Chinese market, itself, is also changing as the internal needs for separated rare earth's grow Already already producer of Lamps, Loudspeakers, Magnets, and TV tubes, China is in an unique position where the potential of its internal market might be more promising than the prospects outside China 1995 has also seen the application market become more diverse and complex. There are new applications growing at a very strong pace (such as battery alloy), applications that are now penetrating their target markets with significantly increased growth rates (such as bonded NdFeB), and some applications that became more complex requiring much more sophisticated products (such as catalysis). Rare Earth producers have to spend significant ressources in order to monitor the market trends in order to predict the demand and then adjust their raw material mix. Even though there is a greater diversity of raw material available, there is still some Rare Earth elements that are in excess, while other are just in balance. As a consequence rare earth producers invest heavily in R&D in order to develop new applications for these excess elements.

Jan 1, 1997

Due to problems with old technologies more and more product designers have turned to liquid crystal (LC) displays, which have consequently experienced phenomenal growth. The success of liquid crystal displays has fostered continued development, to the point where full-color video displays have been realized which can rival. The details of the lens structure and of the devices fabrication and performance are described using the Jones matrix method. Director n can change from point to point and is, in general, a function of space.. The transition can be approached by changing the impurity concentration or, indirectly, by tuning the temperature since the pinning strengths of the random and crystal potential have in general a different temperature dependence. Light from the conventional light source or laser is passed through a polarizer and then incident on the specimen. The resist profile simulation is carried out using the combined data thus obtained. The nematic liquid crystal is clear only when a long range order exists, in the whole medium. At the nematic-isotropic, transition temperature, the medium becomes isotropic and looks clear and transparent.

Jan 1, 2006

By O. Kitamura, H. Kubota

The Harima Works started its ISP operation in 1966 and been expanding its production capacity from 3,000 tonne Zn/month and 1,500 tonne Pb/month to 7,500 tonne Zn/month and 2,500 tonne Pb/month. It is not only treating zinc, lead and bulk concentrates but also secondary materials like Waelz kiln oxide from the Shisaka Works of Sumitomo Metal Mining, waste treatment sludges, industrial wastes and others. Its final products cover Prime Western Grade (PWG) zinc, Special High Grade (SHG) zinc, continuous galvanizing grade zinc, electrolytic lead, cadmium, indium, thallium and sulfuric acid. This paper briefly describes the smelter's historical and present operations. The key data for the current impurity control management and for the distribution of impurities such as copper, iron and arsenic are presented.

Jan 1, 2000

By David B. George

In spite of the many well-known problems inherent in Pierce-Smith converting, it remains the dominant copper converting process. Continuous copper converting and direct concentrate to blister smelting have been commercially available for over 25 years and now produce approximately 15% of copper smelter production. The two fully commercialized continuous converting processes, Mitsubishi MI Process and Kennecott-Outokumpu Flash Converting, and several emerging converting processes are reviewed with view of their potential, limitations, and environmental performance. Some myths regarding these technologies and Peirce-Smith converting are also challenged.

Jan 1, 2002

By F. Patisson

One of the major issues with multiparticle reactors is to handle their multiscale aspect. For modeling, it usually comes to coupling a reactor model (describing the phenomena at the macroscopic scale) with a so-called grain model (simulating the behavior of a single grain or a particle). An interesting approach proposed by H.Y. Sohn (1978) is to use the law of additive reaction times in order to calculate, approximately but analytically, the reaction rate of a particle in the reactor model. Its great advantage, compared to a numerical grain model, is to drastically reduce the computation time, particularly in the case of complex reactor models. This is the approach we retained for modeling the moving bed furnace, a counter-current gas-solid reactor used in the nuclear fuel-making route for producing uranium tetrafluoride from uranium trioxide. The numerical model we developed is 2-dimensional, steady-state and based on the finite volume method. It describes solid and gas flow, convective, conductive and radiative heat transfers, and six chemical reactions involved in the process. The law of additive reaction times is used to calculate analytically the rate of the three principal gas-solid reactions at every discrete point in the reactor. We have demonstrated the validity of this approach by comparing its results with those calculated from a numerical grain model. Also detailed in the paper are the main results of the moving bed furnace model itself and the possibilities of optimizing the process revealed by the calculations.

Jan 1, 2006

By Li Cheng

The SKS copper smelting process was jointly developed by Shuikoushan Mining Corp. and ENFI (Beijing Central Engineering and Research Institute for Non-ferrous Metallurgical Industries) in China. It is a new bath copper concentrate smelting process with oxygen enriched air. The pilot plant testwork was completed successfully in 1993. SKS has demonstrated to be an advanced bottom blown smelting process. This technology got the First Class Prize of Scientific and Technological Progress awarded by CNNC (China National Non-ferrous Metal Industry Corp.) in 1994. The SKS process has significant capital and operating cost advantages. Its environmental and industrial safety and hygiene performance represents a substantial improvement when compared to conventional technologies. The technology has generated great interest in the Chinese metallurgical industry. Feasibility studies and basic designs have been carried out to incorporate in retrofit and green field smelter projects in China and abroad. This paper describes the history of the pilot plant operating data (50 tonnes dry feed/day), and discusses the features of the SKS technology, its application and possible future trends.

Jan 1, 1999