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By Mikael Ersson

A fundamental mathematical model of lance blowing on a bath surface has been developed with a purpose to increase the understanding of various phenomena in top blown oxygen converters. The model is based on the Navier-Stokes equations and turbulence is predicted using the k-model. In the present model the deformation of the liquid surface, caused by the impinging gas jet, is described using a VOF formulation. The mathematical model results have been verified by comparing predicted penetration-depth data with experimental results from physical model trials. The fluid dynamic modeling has also been coupled with the thermodynamic modeling to predict the reaction rate/distribution occurring in the vessel. The focus has been on carbon and a qualitative comparison of the predicted carbon content in the hot spot area and in droplets with experimental data from laboratory trials has been done.

Jan 1, 2006

By Ramana G. Reddy

In the past, many lead-containing slags and wastes were stored in piles or landfills. However, shortages of landfill space as well as increased public, concern about the toxic nature of disposing lead containing industrial wastes in landfills have led to review of disposal methods. Several lead wastes are processed to provide commercial products. They are used on-site in land reclamation projects. or are processed and sold as a by-product. These by-products contain nutrient elements needed for plants or animals and also may contain heavy? metal contaminants such as As, Cr. Cu, Zn and Ph. Use of such by-products containing unacceptable levels of these contaminants could cause plant and animal toxicity. In this paper. role of viscosity in conversion of lead slag wastes into commercial products containing ,low content of lead and other, heavy metals is presented. Effects of slag viscosity on the velocity of movement of metal' and matte prills through themolten slag layer in the melting furnace is discussed. Current and emerging slag cleaning technology, foamed, granulated and pelletized slag technologies are reviewed.

Jan 1, 1995

By John Frederick Colloghon, O&apos

Bulong remains the only hydrometallurgical process plant in the world that recovers nickel and cobalt directly from high pressure acid leach (HPAL) laterite leach liquors without need for precipitation of an intermediate product (e.g. sulphide, hydroxide or carbonate). Direct solvent extraction (DSX) of both nickel and cobalt in combination with electrowinning of nickel has been operation at Bulong since early 1999. Focus in the first years has been on ramp-up and resolution of commissioning problems. More recently the focus has been on de-bottlenecking and process optimisation. A number of significant process problems have been resolved, the most difficult being the formation of gypsum in the nickel solvent extraction circuit. Sound control of process chemistry is essential to ensure the production of high quality nickel and cobalt products at the lowest possible cost. This paper describes the numerous changes and enhancements to the process chemistry and plant equipment at Bulong and discusses the importance of ore leach chemistry on downstream impurity metal removal. Potential additional enhancements to further reduce unit costs are also presented.

Jan 1, 2004

By G. Riverin, C. Simard, W. D. Stevens

"An on-line technique to measure the efficiency of decoating I delacquering processes is being developed by Alcan' s Arvida R & D Centre. Decoating processes are used to remove moisture and coatings from shredded coated material such as Used Beverage Containers (UBC) before melting. Complete removal has been demonstrated to maximize metal recovery. Quantifying the weight of carbon and organic residue adhering to the shred surfaces is very difficult to measure directly, as the material can be highly folded. The technique developed indirectly measures the residue remaining by analysing the concentration of CO evolved in the decoater end zone exhaust gas.A commercial CEMS (Continuous Emission Monitoring System) incorporating an infrared type CO gas analyser was modified for on-line process exhaust gas analysis. Both pilot and plant trials had demonstrated that the CO concentration measured was inversely proportional to the efficiency of the organic removal achieved. As the quality of coated purchased scrap can be highly variable in moisture and organic content, continuous measurement should permit adjusting the feed rate and other decoater process parameters to the quality of decoating required."

Jan 1, 2000

By He De-wen

The influence of coal desulphurization by fungus was experimentally studied. The present results suggest that fungus can effectively remove inorganic and organic sulfur in coal. The main factors that influence the desulphurization by fungus such as pH value, temperature, coal slurry concentration and coal granularity are studied by orthodox experiment and the optimal experimental conditions are as follows: pH value 6, temperature 45 C, coal slurry concentration 10% and coal granularity 100 m. Under the above conditions, fungus can remove up to 44.96 total sulfur and 54.87 inorganic sulfur within two days and their desulphurization rates will increase along with time. Compared to sulfolobas, desulphurization by fungus is steady and more effective and has the advantage of high speed.

Jan 1, 2006

By Hong Yong Sohn

On the occasion of this symposium in my name, I reflect upon the contributions of my academic mentors and early associates who helped shape my professional career. I was fortunate to have these people around me during my graduate work and at the start of my professional career. In forming my view of the technical field and career, they represented academia, research institutions, industry, and different parts of the world.

Jan 1, 2006

By Hong Yong Sohn

On the occasion of this symposium in my name, I reflect upon the contributions of my academic mentors and early associates who helped shape my professional career. I was fortunate to have these people around me during my graduate work and at the start of my professional career. In forming my view of the technical field and career, they represented academia, research institutions, industry, and different parts of the world.

Jan 1, 2006

By Xie Gang

The leaching experiment used by bacteria on the low grade sulfide copper ore which is difficult to leach was carried out. Some leaching bacteria which have good physiological and leaching activity were isolated and domesticated, and were adapted to leaching ore. The effective domesticated method was put forward. Some technological parameters such as ore acidification, potential controlling, leaching method, ore granularity, leaching acidity, leaching liquid quantity and acid consumption were obtained by column experiment and leaching ore in situ under the ore well. The results show it could leach 30.62% of copper from the low-grade sulfide copper ore within 24 weeks by column leaching method, and the bioleaching rate of copper is 22.83% by leaching in situ under the ore well in 8 months.

Jan 1, 2006

By Robert W. Bartlett

Hazardous metal contaminants in liquid and solid wastes and from ground spills are important environmental problems in many metallurgical production operations. Acid rock drainage, from mines and huge quantities of permeable mine waste, is probably the most ubiquitous example. Fixing mine waste contaminants in situ has been practiced, using sulfate reducing bacteria (SRB) and organic reagents as electron donors to create anaerobic conditions and precipitate metal sulfides. Aqueous solutions of sugar and alcohol have been percolated into mine wastes with good results. However, maintaining anaerobic conditions permanently is unlikely, as these solutions are eventually washed out of solid waste and contaminated ground by inflow of either groundwater or meteoric water, allowing re-oxidation from entering air. Emulsions of inexpensive, non-aqueous organic microdroplets dispersed in water provide earth wettablility equal to aqueous solutions and easy percolation into both the ground and mine waste. Subsequent breakdown of the O/W emulsion provides permanent retention of the organic phase, attached to earth particles, that secures lasting anaerobic conditions, precipitates metals as sulfides and prevents re-oxidation of these sulfides. This process and its optimization are described, including experiments with sand-filled columns representing a vertical section through solid waste. Results of organic and metal retention in solid waste are provided from analyses of acid mine water drainage before and after waste treatment.

Jan 1, 2006

By J. H. Meza

La Caridad copper smelter is located in the magnificent but rugged Sierra Madre Mountains. This project presents unusual challenges that require the utmost in detailed analysis and planning. The smelter, owned by Mexicana de Cobre, S.A. de C.V., has an annual production capacity of 225,000 metric tons of copper and 600,000 metric tons of sulfuric acid. It utilizes only the Flash Smelting process. This project will expand the annual production capacity to 270,000 metric tons of copper and 1,000,000 metric tons of sulfuric acid. Offgases from the Flash Furnace and the Teniente Converter will be sent to a mixing chamber, from which it will be led to two sulfuric acid plants. This project will then produce a high quality sulfuric acid.

Jan 1, 1995

By R. D. MacDonald

The papers presented in this chapter cover a wide range of hydrometallurgical topics and might be considered to be unrelated to each other. All of the authors, however, utilized the basic methods of process mineralogy to characterize the reactants in their experiments and the products produced. The wide range of research topics which can be pursued successfully by the use of the methods of process mineralogy is a matter of interest in itself. One might speculate that the methods could be even more widely applied if only their utility were better recognized. These methods for characterizing reactants and products include principally x-ray diffraction, optical micros-copy, wet chemical analyses, instrumental chemical analyses, high intensity magnetic separation, micro-scale gravity separation, differential thermal analysis, micro-hardness testing, and judicious use of the sledgehammer and cold chisel. It is perhaps not by coincidence that most of the papers in this chapter were prepared not by mineralogists, but by hydrometallurgists, who are recognizing the importance of thinking in terms of mineral phases, and not just assays! It appears that the gap between process mineralogy and the mineral industry is closing, and that future AIME sessions promise to become established forums where mutual discussion of such topics as metallurgical "troubleshooting" and process design may become commonplace between plant engineer and process mineralogist.

Jan 1, 1981

By Albert W. Spitz

Profitably recovering copper and precious metals from copper bearing scrap is a demanding and frustrating combination of art, science and economics. With fluctuating markets, varying raw materials and increasingly stringent environmental regulations requiring process revisions, practically everything is changing. The volatile copper market constantly shifts the percentage of copper in the scrap that can be economically processed. Scrap that has value one day may incur a disposal cost the following day. Also with less copper in the scrap, more residuals, slag, fume, etc. are generated which frequently present disposal problems and infrequently generate income. The ever increasing amounts of electronic scrap add value to the copper produced by virtue of the precious metals present. Printed circuit board materials create more slag and organic off gases which must be treated. Finally, the emphasis on reducing emissions of organics and other metals, especially lead, is a continuing challenge. Stack gases, fugitive emissions and ambient air quality all demand constant surveillance.

Jan 1, 1997

By Pradeep kumar Jha, Manas Mohan Mahapatra, Sabin Kumar Mishra, Satish Kumar Ajmani, Satish C. Sharma

"Due to mechanical/ electrical failure in the C.C. line or inadequate availability of molten steel from coming ladle, sometimes one/two outlets of a multi-strand tundish in continuous casting unit is closed. Closing any of the outlets affects the flow distribution inside the tundish which in turn governs the quality of steel coming out. Hence it is important to study which of the outlets should be closed to have proper results in terms of flow behavior and inclusion removal inside the tundish. Present study aims at finding the effect of closing one or two outlets on flow behavior and inclusion removal in a multi strand tundish. It was found that closing the near outlet (outlet near to the inlet) increases the inclusion removal tendency than closing the other two outlets in a six-strand billet caster tundish (only three outlets are considered because of symmetry).IntroductionContinuous casting process transforms molten metal into solid on a continuous basis. This process is the most efficient way to solidify large volumes of metal into simple shapes for subsequent processing [1]. Molten metal is tapped into the ladle from furnaces. From the ladle, the hot metal is transferred via a refractory shroud (pipe) to a holding bath called a tundish. The tundish allows a reservoir of metal to feed the casting machine while ladles are switched, thus acting as a buffer of hot metal as well as smoothing out flow, regulating metal feed to the moulds and cleaning the metal [2]."

Jan 1, 2012

By David M. Beckwith

Increased globalization and outsource manufacturing complicate the procurement and enforcement of intellectual property rights on a worldwide basis. Recent legislative and case law developments in the United States highlight the importance of a multinational intellectual property strategy. IP lawyers David Beckwith and John Hankins will discuss planning and pitfalls in this rapidly changing trans-border environment. Topics to be discussed include harmonization with international patent laws, protecting your technology and market space with a comprehensive approach to IP, and patent enforcement issues relating to import/export of products and components in the United States.

Jan 1, 2006

By David C. Lynch

The molecular form of trace elements in matte has been shown to depend on the chemical potential of sulfur and the propensity of the trace element to form a sulfide. Of the four trace elements (As, Sb, Bi and Pb) arsenic and lead behave nearly as opposites, with lead readily forming a sulfide while arsenic forms complexes with free copper and ion in the matte. Antimony and bismuth both display the dissolution characteristics as As and Pb, suggesting that these elements dissolve in matte in multiple forms of significant concentration. While in the present investigation the dissolution characteristics of all four trace elements are examined, the primary focus is on the multiple dissolution behavior of Sb and Bi.

Jan 1, 1995

By M. L. Free

Electrowinning is directly impacted by many parameters that include electrolyte composition, voltage, current density, contact resistance, temperature, electrode spacing, and fluid flow as well as many other interrelated factors. The effects of these parameters are primarily related to thermodynamics, mass transport, and electrochemical kinetics. In this study thermodynamic, mass transport, and electrochemical kinetic equations are simultaneously solved to determine the effects of such parameters on electrowinning current efficiency, power consumption, electrodeposit morphology, and electrodeposit distribution. Modeling predictions will be compared with experimental results.

Jan 1, 2006

By F. J. Tavera

The colloid flotation of lead carbonate precipitates in aqueous media is studied at a pH of 7. The flotation system consisted of five spargered flotation cells in a serial array. The flotation system was operated under controlled conditions of superficial air velocity, superficial liquid velocity, frother concentration, and collector concentration. The measured variables were gas hold-up, bubble size, superficial bubble surface flux, and lead recovery (reported to the concentrate). The experimental data show that it is possible to separate as much as 97% (w/w) lead from the aqueous media when the superficial gas velocity is 1 cm/s and the superficial liquid velocity is 0.19 cm/s.

Jan 1, 2006

By Tian Li

Molecular crystal growth during gibbsite precipitation from caustic aluminate solutions under different flow regimes was investigated in three different laboratory precipitators. The gibbsite precipitation experiments were conducted at the same temperature, initial liquor composition and seed type. The Taylor-Couette precipitator and the stirred tank precipitator were operated, respectively, under the laminar and turbulent flow regimes, while the bottle roller precipitator was operated in a complex flow regime, where fluid flows are generated by the end-over-end rotation of the bottles. Comparison of the growth rate estimates from the different flow regimes showed good agreement, which suggests that the hydrodynamic regime has little or no effect on gibbsite crystal growth under the operating conditions employed in this work. The growth rate estimates from the current precipitation study showed a second order dependency on supersaturation and is consistent with a screw dislocation growth mechanism. The findings of the current work are in agreement with previous gibbsite crystal growth studies published in the literature.

Jan 1, 2003

By Funsho K. Ojebuoboh

With several "green" applications in the horizon, bismuth has become an even more important minor metal in the smelting and refining of lead. Smelters with a complex sulfide feed invariably deal with bismuth. Its behavior during the smelting of lead in conventional sinter - blast furnace operation is discussed. Because it readily deports to the lead phase during the refining of lead, its separation from refined lead remained unsatisfactory in early lead production. When commercial requirements of bismuth in lead became more stringent early this century, the procedure whereby calcium and magnesium is used to debismuthise lead was developed. The present conduct of this 1936 process, the Kroll Betterton process, is discussed with emphasis on operational improvements.

Jan 1, 1995

By M. Sripathy, K. V. Sharmal

"The conventional fiber reinforced plastic does not participate in the plastic deformation or enter the large plastic deformation state during collision. On the other hand, sandwich structure allows more plastic deformation, which improves the energy absorption efficiency. The objective of this study is focused on the investigation of the crushing of sandwich structure made from sisal / coir / bamboo/ glass fabrics as reinforcement and with polyester resin to form the composites skin and with polyurethane foam as the core. Experiments were conducted, showing that the underlying crushing mechanism of sandwich structures is very different from that of solid-section thin-walled structures. When a sandwich is subjected to crushing, the core deforms in the shear mode and the face bends independently. The damage is through the width zone of crushed foam core accompanied by a residual crushing in the foam. It is shown that such damage causes a significant reduction of compressive strength. Results show that glass/polyester and bamboo/polyester skin based sandwich structures have superior compressive strength. Coir /polyester based sandwich structure come next to glass/polyester sandwich structures in this aspect which is then followed by Sisal /polyester based sandwich structures.IntroductionCellular polymeric foam sandwich structures are often employed in shock mitigating applications. The cellular polymeric foam has several favorable properties, such as, low density, relatively high strength-to weight ratio and a significant degree of crushability. This high crushability is the result of the large void ratio in such materials, which also facilitates the collapse of cell walls via bending and buckling [1]. A few feasibility studies on FRP sandwich panels show that the panels efficiently provided high mechanical performance for minimum weight [2]."

Jan 1, 2012