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By Yue Tian, Shengqian Wang, Lifeng Zhang

This paper is to discuss the removal of non-metallic inclusions from molten steel using a high frequency magnetic field. In experiments, a certain amount of aluminum was added to the molten steel in a crucible to generate aluminum inclusions. A layer of aluminum clusters were observed close to the wall of the crucible after the electromagnetic (EM) field was imposed. Three dimensional EM field and fluid flow simulation were performed and showed that over 91% inclusions transported to the skin depth (2.31 mm) of the molten steel. The calculation of inclusion removal agreed well with the experimental observation. The separation mechanisms of inclusions from the molten steel by the high frequency EM field were discussed.

Jan 1, 2014

By Maneesh Singh

During the various stages of iron & steel production a number of iron-rich by-products are generated. The traditional way to recycle them back to the blast furnace has been the balling - sintering process. These by-products can also be made into cement-bonded agglomerates for use as burden material for blast furnaces. In order to improve the quality of agglomerates the effects of various processing parameters on the properties of cement-bonded briquettes have to be controlled. This paper looks into the various aspects of producing cement-bonded agglomerates and using them as burden material for blast furnaces.

Jan 1, 2003

By Jacqueline JAlexander

Two of the most important phenomena which govern the continuous casting process and determine the quality of the product are the fluid flow and the heat transfer. Steel flows into the mold through the ports of a bifurcated submerged entry nozzle (SEN), which directs the jet to the mold narrow faces where the superheat contained is dissipated on the solidifying shell. Many important aspects of the fluid flow in the mold are transient and difficult to control. However, the time-averaged flow pattern in the mold is greatly influenced by the nozzle geometry, the submergence depth and the mold dimensions. The aim of this work is to analyze the relationship between the heat transfer and the fluid flow pattern inside the mold using the CFD technique at several operating conditions.

Jan 1, 2009

Rotary kiln incinerators are widely used in the incineration of various types of hazardous wastes. However, the complex transport processes within the incinerator are not well understood. Due to large variations in waste types and difficulties in feed characterization, the incineration process meets great challenges in a smooth operation, and expects uncertainties in the process chemistry and emission control. In order to get better understanding of the incineration process, process simulation was made on the kiln behavior by using Computational Fluid-dynamics (CFD) to characterize gas flow, temperature distribution and waste combustion in the incinerator. Temperature measurement was conducted in an operating incinerator to validate the CFD model. This paper addresses the environmental issues related to the hazardous incineration process, and reports the recent simulation results on gas flow and mixing, combustion heat transfer, and potentials to reduce emissions.

Jan 1, 2002

By W. G. Davenport

Chapter 13 evaluated the %02 in blast, industrial oxygen and oil requirements for smelting FeSrCuFeS2 concentrates~ This chapter examines high eu grade CU2S-CuFeS2 concentrates the same way.

Jan 1, 2001

By O. A. Bascur

Applying the latest information technologies in mining and metallurgical complexes has become a serious challenge to management and technical teams. Emerging component design is changing the way the user relates to the desktop. Connectivity between mining and metallurgical process operations and their business systems has become a reality. Expanded use of plant information on the desktop is a standard tool for revenue improvement, cost reduction and adherence to production constraints. The industrial component desktop support access to information for continuous improvement and innovation by staff personnel and engineers. Collaboration between groups enables the implementation of an overall process effectiveness index based on losses due to equipment availability, production recovery and quality rate. The integration of information from mining, mineral processing and metallurgical performance monitoring increases production efficiency, even when many elements cannot be measured directly. Three case studies of large mining/metallurgical complexes are highlighted.

Jan 1, 1999

By M. GONZALES-FERNANDES M

Natural rubber/organophilic clay nanocomposites were prepared and characterized. A brown bentonite from Paraiba’s State, Brazil was modified with a sodium salt and treated with quaternary ammonium salt hexadecyltrimethyl ammonium chloride. The clay in its natural state, after cation exchange with sodium and after organophilization was characterized by XRD, IR, SEM, thermal analysis. Nanocomposite samples were prepared containing 10 resin percent of organophilic clay. The vulcanized samples were analyzed by XRD, SEM. The nanocomposites obtained showed improvement in their mechanical properties in comparison with samples without clay.

Jan 1, 2015

By G. Sterzik, W. A. Jankola, T. L. Salway, D. J. McKay

At Trail, British Columbia, Cominco's zinc leaching and solution purification processes include direct pressure leaching of zinc concentrates, leaching of fume from the lead smelter, leaching of calcine and electrolyte purification. These processes have been adapted to match the unique characteristics of Cominco's integrated zinc and lead operations. Recent modifications include changes to the purification process and iron-residue handling circuits. In 1997, a new five-compartment autoclave, complete with ancillary equipment, was installed in the pressure leaching plant. This paper discusses these changes, the current flowsheet and further improvements.

Jan 1, 2000

By B. Q. Li, S. P. Song

"Numerical models are developed to represent complex electromagnetic, free surface deformation and fluid flow phenomena in floating zone refining processes with radio frequency inductive heating. The computational methodology is based on the coupled finite/boundary element method for the electromagnetic field distribution and the Galerkin finite element method for magnetically driven fluid flow and free surface profiles of the molten zone. With the models, the complex transport and free surface phenomena in a floating zone system can be studied as a function of various operating conditions including applied current, frequency, inductor position and shape, surface tension, floating zone diameter and height. Results show that the equilibrium shape is sensitive to the height of the molten zone and that the free surface shapes can have a significant effect on the melt flow in the molten zone. Our extensive simulations also suggest that to ensure accurate results, the same mesh should be used, whenever possible, for both the electromagnetic forces and fluid flow calculations.1. IntroductionThe floating zone processes have been widely used in the materials industry to grow ultra-pure rare earth metal or semiconductor single crystals for sensor or electronic applications that have a tough demand on purity. Developed based on the principle of magnetic melting/levitation, the processes possess a main advantage that the molten zone is supported in air by the electromagnetic forces generated by the coil (see Figure 1), and therefore is free from contamination from a container. Consequently, the final products made from the floating zone processes have higher inherent purity than those by other techniques [1-4].Complex physical phenomena occur in the floating zone processing of materials. These include free surface deformation, magnetically-driven melt flow, which may be turbulent or mildly turbulent [5] depending on the applied conditions, and solidification. Thermal stresses also develop in the single crystals, which are affected by the flow and temperature field and which can have direct implications to qualities of single crystals [6]. An understanding of the fundamentals governing these physical phenomena can be of critical value in elucidating the physics that controls the properties of the metal or semiconductor crystals being produced, thereby providing a rational basis for process improvement and quality control."

Jan 1, 1997

By Alireza Zakeri

To evaluate the behavior of minor elements in the copper smelting process, activities of silver, selenium and tellurium at minor concentration were determined at 1473 K within the miscibility gap of the Cu-S-Me (Me = Ag, Se, Te) and Cu-Fe-S-Me systems varied in Fe/Cu ratio. Phase relations between the immiscible metal and matte phases in the foregoing systems were first established by a quenching technique at 1473 K to supplement the activity measurement data. A Knudsen-effusion mass spectrometer, capable of handling complex gaseous systems and relatively small vapor pressures, was adopted for activity determination. Using a multiple Knudsen-cell, the ion intensity of minor element in the sample under study was measured simultaneously with that in a reference sample. Activity was obtained from the ratio between the measured ion intensities as well as the known activity value of the minor element in the reference sample. Limiting activity coefficients of the minor elements were correlated with composition of the matte. Based on the experimental results, the vaporization behavior of the minor elements has been discussed.

Jan 1, 1999

By S. Yokoya

With increasing requirement of steel productivity and quality in continuous casting in the conventional casting system using an immersion nozzle, it is very difficult to establish a reasonable molten flow pattern. In order to overcome this difficulty, we propose a new method of imparting swirling motion onto the flow in the immersion nozzle and to control the flow pattern in the mold. Following results have been obtained during the studies. For the case of slab continuous casting mold: High amplitudes of oscillation with a period of 10 to 15 seconds are observed in the outlet flow of the immersion nozzle and meniscus flow in the conventional casting system, while these phenomena are remarkably suppressed using swirling motion in the immersion nozzle, which leads to very calm and uniform flow pattern at the outlets of the immersion nozzle, in the mold and on the meniscus in the mold; For the case of billet continuous casting mold: (1) heat and mass transfer near the meniscus can be remarkably activated compared with a conventional straight type immersion nozzle without swirl, and (2) Quite different mold flow patterns are observed between the divergent and straight immersion nozzles. Heat and mass transport in the mold using the divergent nozzle is much more reasonable compared to that of straight nozzle. The findings, mentioned above, are very useful to control the flow pattern in the slab, and billet continuous casters. Such effectiveness of swirling flow in the SEN on the mold flow has been put into practical use. As a result, remarkable progress on the quality and production of continuous casting products has been observed in practical application.

Jan 1, 2006

By A. Ohno

"A new near net shape casting process, OHNO Continuous Casting (OCC), has been recently developed. In this process, molten metal is fed into a heated mold maintained at a temperature above the solidification temperature of the metal being cast. Solidification begins from the central core of the casting rather than the wall of the mold. With the heated mold, the formation of crystals on the mold wall is prevented and solidification occurs out of contact with the mold surface. This produces near net shaped products with smooth, mirror-like surfaces and unidirectional grain structures free from cavities, porosity and segregation. Any crystals formed at the beginning of solidification decrease in number as solidification progresses and eventually a single crystal product is obtained. This process is applicable to any metal alloys, converting them into new materials with superior properties and quality.IntroductionAs a result of growing technical demands for more advanced and diversified materials, the OHNO Continuous Casting (OCC) technology has found many new applications in industry. Considerable interest in the process has been shown in Japan and other countries because of its distinct ability to:produce a single crystal, (1)produce a remarkably clean cast surface without a witness mark,provide extremely good ductility,and reduce casting defects and segregation.This paper provides an overview of the principle of the OCC process and describes the remarkable characteristics of the material produced by this method."

Jan 1, 1988

By Stavros A. Argyropoulos, Henry H. Hu

"The assimilation of exothermic additions in liquid metals exhibit an array of unique coupled heat, mass and momentum transport phenomena. These phenomena are further complicated by the presence of a moving boundary.This paper describes a) A mathematical model which simulates the complex phenomena, and b) An extensive verification of the mathematical model. The SIMPLER algorithm was employed to solve numerically the pertinent partial differential equations. The computational results indicated that the exothermic heat of mixing led to a rapid increase in temperature around the moving boundary, which produced an enhanced convective flow in the liquid phase. The intensification of fluid flow around the moving boundary resulted in an acceleration of the melting process.Verification of the model was carried out in two contexts. The first was, in a low temperature physical model consisting of ice immersion in different sulfuric acid solutions. In this physical model, both temperature and velocity measurements were carried out. The model results were compared with experimental measurements and they were found to be in excellent agreement. The second context employed high temperatures, involving the assimilation of silicon in high carbon liquid iron. The model was also applied to predict fluid flow, heat and mass transfer for these high temperature experiments and a good agreement was obtained.In addition new dimensionless heat transfer correlations that quantify these complex phenomena will be presented."

Jan 1, 2001

By Susana Caballero, Lourdes Yurramendi

Air Pollution Control (APC) ashes from Municipal Solid Waste Incineration (MSWI) plants need to be treated prior to landfilling due mainly to their heavy metals content. This research evaluates the capacity of the APC residues to sequester carbon dioxide, while the ash becomes stabilized for storage. It has the benefit of using two wastes, with no addition of any raw material. APC samples from different MSWI plants were treated by gas/solid accelerated carbonation at different temperatures and carbon dioxide concentrations to evaluate the residue behaviour to the process. The extent of carbonation was evaluated by means of weight gain upon carbonation and by the measurement of the final carbonate content. The APC residues were analyzed before and after the treatment in order to know their composition and their leaching behaviour according to the criteria for the acceptance of wastes at landfills established by the European Council Decision 2003/33/EC.

Jan 1, 2008

By S. D. Prosser

The earliest record of slag in the world was the discovery of the remains of a copper blast furnace in Southern Israel, which has been carbon dated at 3500BC, nearly 6,000 years ago. Slag in Australia is a much more recent phenonenum with the first iron blast furnace commencing operations in 1848. The early days of metal smelting in Australia were marked with many company failures due to a variety of reasons. This paper traces the progress of metal and slag production from those early days up to the present times

Jan 1, 1994

By John L. Sundstrom

Complete systems were designed -and are in operation to recycle the effluent streams and to remove impurities from tankhouse. electrolyte, Heavy em¬phasis was placed on making usable products from as many streams as poss¬ible at minimum capital and operating costs. Almost complete recycling: and reuse of water and sulfuric acid were paramount. Techniques used in-clude solvent extraction - electrowinning, evaporation - crystallization and filtration.

Jan 1, 1992

By Norbert L. Piret

During smelting of copper, arsenic in the feed reports to a large extent to the gas phase and some enters the anode copper. From the gas phase it is transferred during wet gas cleaning directly, or indirectly after dust processing, to aqueous solution. During the electrorefining and anode slimes processing, the anode arsenic content is also transferred to aqueous solution. Technology for the efficient removal of arsenic from process streams and cleaning of aqueous effluents is well established. However, the arsenic-bearing products, which thereby are generated, can vary widely in consistency, quality and quantity, from large amounts of gypsum contaminated with water-soluble arsenic compounds to residues with high arsenic content ' or arsenic products. Arsenic management in a copper smelter not only is involved with the duty of compliance to the gaseous and aqueous emissions standards but also should have as objective the minimization of the generation of arsenic-bearing and, in general, heavy metal-bearing solid waste. The present paper outlines options and the associated economic aspects for minimization of arsenic-bearing solid waste generation, for improvement of the environmental compatibility of the residues to be deposited and for the .production of commerciable arsenic compounds under appropriate market conditions.

Jan 1, 1999

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

By W. Mueller

The function of a process mineralogist in the operation of a copper mine and plant is to assist in the identification and classification of the operation's main throughput. These include ore, concentrates, slag and matte, and to a lesser extent, refined products. In addition, a number of other products not normally thought of in association with mineralogy are examined. These include scales from submersible pumps, failed boiler tubes, acid plant, and shaft furnace; characterization of inclusions in failed compressor gear teeth as well as in copper rod; and flue dusts from a smelter, air transported particulates and coatings on passive copper anodes in the refinery. Techniques and equipment required for these studies include simple hand magnets to the high intensity Isodynamic separator, visual examination to electron microscopes, x-ray equipment, DTA, IR, heavy liquid separation, and contracted services of custom laboratories. Several examined products from Magma Copper Company have been selected to illustrate the range of techniques and equipment required by a process mineralogist.

Jan 1, 1981

By Ron Bernard

HW Process Technologies has successfully developed and commercialized various applications utilizing Engineered Membrane Separation (EMS?) systems for the processing of acidic copper hydrometallurgical solutions and wastewaters. Copper hydrometallurgical EMS? applications include water balance control and increased copper concentration in heap and dump copper leach operations, tankhouse bleed stream treatment to separate/recover copper and cobalt from iron, and removal of PLS/Electrolyte suspended solids/colloids to eliminate "crud" formation during copper SX/EW. Similar applications are underdevelopment to provide ionic separations in copper refinery bleed streams, copper smelter acid plant streams, as well as organic/LIX removal from aqueous electrolyte and raffinate streams. Copper mine wastewater EMS? applications include treatment of copper leach solution contaminated groundwaters for copper recovery and treatment of unwanted heap/dump drainage to provide enhanced precipitation, a smaller precipitation plant, improved operating costs and better quality discharge water, particularly in terms of TDS and sulfates. A discussion of the EMS? technology and general separation results on typical process solutions and wastewaters will be presented. HW Process Technologies, Inc. commercial installations treating copper pregnant solutions and leach solution contaminated groundwaters are in-place at an old Asarco smelter/refining operation, Mexicana de Cananea copper mine, and a major U.S. copper mine, with several additional installations pending. Several case studies, including results from a selection of these installations, will be included with detailed capital, operating cost, and system payback data.

Jan 1, 1999