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By David G. C. Robertson

A new approach is described for the calculation of the kinetics of metal/slag, metal/slag/gas, and metal/matte/slag/gas reactions. The algorithm assumes that equilibrium is achieved at the interface between phases, and uses an equilibrium solver (such as SOLGASMIX) to compute the equilibrium state at the interface at each time step during the reaction. For multiple phase systems a number of unit operations, representing the different phases and interfaces, must be connected together in a reasonalbly complex manner, and the METSIM software package has been utilized for this purpose. The new approach is superior to the SMAK software developed by the author and his co-workers over the past decade, for the reasons discussed in this paper.

Jan 1, 1995

By M. Tomita

One of the most essential factors for a custom smelter to strengthen its competitive power is to Improve its comparative standing in purchase of concentrates from the world market. It is especially critical for Japanese smelters who depend almost 90% of their raw materials on import. In order to accomplish this breakthrough, the development of the new technology which enables us to treat concentrates containing higher Impurities is inevitable. Nippon Mining Company Ltd. made an intensive research on processing complex ore for three years from 1979, and successfully developed an original hydrometallurgical process to treat converter dust for eliminating impurities from the copper smelting circuit. The commercial plant was constructed at the Saganoseki Smelter & Refinery in 1982, and its nine years operation has been satisfactorily proven the advantages of the technology. The concept of this process and its operational performance are discussed.

Jan 1, 1992

By Kyle S. Brinkman, Kenneth L. Reifsnider, Fazle Rabbi

"Mixed ionic and electronic conducting (MIEC) ceramic membranes are HeteroFoaM's which play an essential role in a number of energy conversion related systems including the solid oxide fuel cell (SOFC), oxygen separation and permeation membranes, partial oxidization membrane reactors for natural gas processing, and high temperature electrolysis cells. Dual phase oxygen membranes consisting of an ionic conducting phase Ceo.sGdo.z02 (CGO) and an electronic conductive phase C0Fe204 (CFO) were fabricated and characterized by structural (XRD), microstructural (SEM-EDS) and broadband dielectric measurement techniques. In-situ measurements of the dielectric properties of working oxygen separation membranes are presented which indicate that the material's dielectric behavior can be an indicator for MIECperformance.IntroductionCeramic membranes which transport oxygen ions play an essential role in a number of energy conversion related systems including the solid oxide fuel cell (SOFC) [l ], oxygen separation and permeation membranes in the commercial and nuclear arena [2, 3], partial oxidization membrane reactors for natural gas processing [4], and high temperature electrolysis cells [5]. For the electrolyte functions, the membranes must transport oxygen ions only. On the other hand, permeation membranes, typically used in combustion devices to support oxy-fuel combustion or for partial oxidation reactions involving the production of synthesis gases, require mixed oxygen ion and electronic conduction (MIEC). Traditionally the tailoring of the ratio of ionic conductivity to the materials electronic conductivity, measured as the transference number, has been accomplished by the introduction of aliovalent doping elements creating point defects in the material facilitating the diffusion of charged species. However, several decades of research have not yet produced single phase materials which possess the concomitant ionic and electronic conductivity required for use in membrane separation applications. It is clear that novel ""dual phase"" heterogeneous materials will be required and that the surface reactions of these materials will be of particular importance as the industry moves toward thin films membranes [6]."

Jan 1, 2013

By Carlos Maurício. F. Vieira, Lázaro A. Rohen, Sérgio N. Monteiro, Rafael G. de Castro, Gustavo X. Borges, Maycon A. Gomes, Frederico M. Margem, Anna C. C. Neves

Economic and environmental benefits are motivating studies on natural fibers, especially lignocellulosic extracted from plants, have been studied to substitute synthetic fibers, such as glass fiber as reinforcement in polymer matrices. By contrast to synthetic fibers, natural fibers have the disadvantage of being heterogeneous in their dimensions specially the diameter. About the hemp fiber, little is known of their dimensional characteristics. The aim of the present work was to statistically characterize the distribution of the diameter of hemp fibers. Based on this characterization, diameter intervals were set and the dependence of the tensile strength of theses fibers with a corresponding diameter was analyzed by the Weibull method. The diameter was measured with precision using a profile projector. Tensile tests were conducted on each fiber obtain mechanical strength. The results interpreted by Weibull statistical showed a correlation between the resistances of the fiber to its diameter.

Jan 1, 2015

By J. Fogarty, J. Sofra

The mobile telecommunications sector is one of the fastest growing industries worldwide. However, increasingly stringent environmental regulations are placing pressure on manufacturers to accept responsibility for end of life products. The companies are therefore exploring avenues to recover the valuable components contained within the mobile telecommunications devices thus reducing the quantities of toxic components going to landfill. Batteries used to power the devices, are typically based on either nickel-cadmium, nickel metal hydride, or lithium ion cells. They contain toxic metals including nickel, cadmium, lithium, potassium, lead, and cobalt in a complicated arrangement of battery cells surrounded by a metals then plastic casing. The Ausmelt Catalytic Waste Converter (CWC) for waste treatment and recycling is well suited to processing all three mobile phone battery types for the recovery of valuable metals in marketable products that can be recycled to industry without turning out harmful levels of toxic emissions. Ausmelt recently demonstrated the capabilities of its CWC by continuously processing 4.5 tonnes of nickel-cadmium batteries. Using Ausmelt's pilot plant facility in Australia, the nickel-cadmium batteries were processed to produce a nickel iron sulphide (matte), a cadmium fume and a final slag which satisfied CS toxicity leach test criteria and was safe f<~r disposal to landfill. This paper explores the commercial development of the Ausmelt CWC for treating each of the three battery types in light of (a) the outcomes of the recent demonstration, and (b) the current and expected future availability of batteries for processing.

Jan 1, 2000

By John Nauman

Liquid ferrous silicates that are related to cop- per slags have been studied as media for the transfer of heat in pyrometallurgical processes. The effective thermal diffusivities have been measured from 1025Oto 1400°C, and values in the range of 0.004 to 0.007 cm2/ sec have been obtained. The heat-transfer characteristics of these slags have been determined by measuring the rise of temperature of a cold nickel sphere immersed in the liquid slag. The sphere is spun about its vertical axis to obtain a well characterized flow of liquid about the sphere. The principal barrier to the transfer of heat from the bulk slag to the metal sphere is a solid shell of slag that forms around the sphere and subsequently melts. It appears that the detailed nature of this shell is important to theheat- transfer process. A mathematical model is used to predict the rate of heating of the sphere, and to evaluate various aspects of the system that can influence the transfer of heat.

Jan 1, 1976

By Robert S. Gärtner

The selective aluminum extraction by 3 different calixarenes (p-tert-butyl-calix[4]arene-tetra¬2-acetic-acid-ethyl-ester, p-tert-butyl-calix[4]arene-tetra-2-acetic-acid and p-tert-butyl-calix-[4]arene-di-2-acetic-acid-ethyl-ester) from an industrial pickling bath solution was studied. The pickling bath solution contained hydrofluoric and phosphoric acid as its main components. The aluminum removal was not successful and also no significant extraction of trace metals present was observed.

Jan 1, 1999

By Rajesh S. Ransing

An intelligent tool has been developed to analyse the quality of diecast components. The influence of both design and process parameters has been studied in great detail. The tool, based on expert systems related technologies, can identify the causes for the defective castings manufactured. Design related causes such as gate position; gate area, runner design etc. as well as process related causes such as cycle time, cavity filling time and melt temperature are suggested by analysing the data on defective castings for a manufacturing campaign. This intelligent analysis is useful for both design as well as production engineers in the decision making process. All the causes for the occurrence of defects are classified into two categories. The firs category is the &apos;rootcauses&apos; i.e. the causes which are related to the actual process, material and design parameters and which can be directly monitored. The second category is more abstract in nature and is classified as `metacauses&apos;. These capture the scientific rationale implicit in the cause and defect relationships. This knowledge on causes and defects is represented in the form of a structured graph rather than by a set of rules, which, coupled with forward reasoning and heuristic search techniques results in an elegant and efficient approach. Uncertainties and the degree of relationship among causes and defects are represented by a fuzzy probabilistic model.

Jan 1, 1994

By R. Winand, M. Degrez, C. Temmerman

"The influence of the copper electro crystallization inhibitors (mainly thiourea, gelatin and chloride ions) is studied in a new fully automatic pilot plan. This paper describes the conception and the building of this plan. The new approach is to reproduce the experimental conditions observed in the industry with the three additives present simultaneously in the electrolyte and secondly to study the influence of a slight modification of the concentration of one inhibitor, the others being present in the electrolyte with their industrial nominalconcentrations.1. INTRODUCTIONDespite the fact that gelatine, thiourea and chloride ions have been used in copper electrorefining for a long time, precise knowledge concerning their influence on the cathode deposit, metallographic structure and associated properties is still lacking.Many authors studied the influence of each additive separately, or of two added at a time. Only a few authors studied the combined influence of the three additives added simultaneously. The general conclusion that can be drawn is that the combined influence is far from that forseen from the influence of each additive separately, or even from two additives used at a time. Moreover most of the experiments described in the literature were performed by adding all additives at once initially. It is however, well known that gelatine looses a great part of its activity during the first half hour due to degradation by sulfuric acid (as shown by the cathode overpotential drop). Thiourea is rapidly replaced by a number of degradation mole,cules and complex ions including cations from the solution, changing even the equilibrium between Cu, Cu(I) and Cu(II).Chloride ions are consumed by precipitation.A number of successive research projects [1-9] led pregressively to the concept that, in order to obtain reproducible results representative of industrial cathodes, it was necessary to simulate as far as possible industrial conditions. It was essential that all additives were added continuously during the electrolysis, with, as consequence, a continuous bleed.The purpose of this paper is to describe the concept of a new fully automatic pilot plan for copper electrorefining and to present the first results."

Jan 1, 1997

By Richard L. Summers

The shaped charge has proven in various military and industrial applications to be an effective penetrator of materials. Upon initiation a detonation wave traverses the explosive billet, collapsing a metallic liner and creating a jetting process. From multiple non-simultaneous flash radiographs of the jet in free flight, the observer can study the collapse, formation, and growth of a shaped charge jet. Digitization of a particulated jet&apos;s position and shape from the radiograph into electronic storage files provides the experimentalist with an efficient basis for data reduction. With the aid of a simple personal computer, one can in a matter of minutes generate a wealth of information concerning jet formation after initiation and thus gain insight into the quality of its manufacture, design, and assembly. This paper will in detail explain the methods in place for fully automated data reduction of radiographic films. Methods of computer aided digitization of particulated jets and analysis of physical jet characteristics and performance will be discussed.

Jan 1, 1992

By A. P. Paiva

With the aim of establishing a valuable alternative to the conventional methods, studies regarding the recovery of precious metals by solvent extraction have been increasing over the past few years. In this work, the selectivity of extraction presented by Cyanex 471X toward silver is investigated. Simulated chloride solutions considering contents of iron and copper usually present in actual leaching practice were used. The characterization of the aqueous solutions - in terms of the multiple equilibria established by the chlorocomplexes of the different metals and their relation to the total chloride concentration of the base-electrolyte - was successfully carried out by cyclic voltammetry. The results obtained support the important contribution of the electrochemical techniques for the understanding of the overall extraction phenomena.

Jan 1, 1994

By Frank A. Vonesh

In order to reduce the amount of visible, airborne emissions in the Metals Industry, a new Industrial Gas Technology was developed by Air Liquide. This patented technique is called ALECT?, Air Liquide Emission Control Technology. Demonstrations have been conducted for many cutting and lancing operations as well as for hot metal transfer from vessel to vessel. Fume reductions of 90% and greater have been achieved in actual practice. Air Liquide continues to improve the process and the associated control equipment.

Jan 1, 1994

By A. Lakschevitz

The Amazon region offers a large potential for gold extraction but its peculiar characteristics such as heavy rains, lacking of roads and general infra-structure, nature of the ore deposits, etc.. do require special care in plant design. REMETÁLICA has developed a know-how is designing leaching plants which have been demonstrated to be profitable under those tropical weather conditions. The solutions adopted are related to general process route, leach liquor distribution and flow pattern, conditioning of solids and effluent treatment. These plants, now operating in South America countries, demonstrate the success for the technology developed. A tipical plant with 800 t/day ore processing capacity, may require an investment of US$ 1.200.000,00, arid have? a pay back period of a few months, depending on ore grade.

Jan 1, 1989

By T. Shimizu

In Japan, the emission standard of selenium in effluent was set at a maximum of20 mgll in Feb. &apos;94 for the first time, and it is scheduled to be further decreased to a maximum of 0.1 mg/I from Feb. &apos;97 due to tightening of the Water Pollution Prevention Act. Selenium (IV) and (VI) are generally found in effluent from precious metals refineries. Although selenium (IV) can be easily eliminated by some reducing agents, selenium (VI) is more difficult to be reduced. Therefore, many smelters are having difficulty in complying with the new emission standard. At Mitsubishi Materials&apos; Naoshima smelter, the behavior and the elimination of selenium in effluent have been extensively investigated. As a result, it was found that two strategies were particularly effective. One of them is improving the overall operation of precious metals refinery, that is, feeding uniformly the effluent to the waste-water treatment plant, reducing the effluent volume by recycling and recovering more selenium (IV) in the effluent. The other is eliminating selenium (VI) in the effluent from the precious metals refinery. It was found that selenium (VI) can be effectively reduced by using hydrazine under high? sulphuric acid concentration and high temperature conditions. By using these measures, it is considered that Naoshima Smelter will be able to comply with the new emission standard.

Jan 1, 1996

By Andy Judge

"In traditional Permanent Magnet Machines, such as electric motors and generators, power is transmitted by magnetic flux passing through an air gap, which has a very low magnetic permeability, limiting performance. However, reducing the air gap through traditional means carries risks in manufacturing, with tight tolerances and associated costs, and reliability, with thermal and dynamic effects requiring adequate clearance. Using a magnetically permeable, high thermal conductivity material has the potential to improve magnetic performance, while at the same time offering performance advantages in heat transfer.Ferrofluids can be used to improve permeability in the rotor I stator gap. However, there are several tradeoffs in this approach. Fluid immersion comes with an increase in fluid friction loss compared to the windage losses of a traditional system. Isolating the rotating components from the ferrofluid can offset this effect. Also, while the magnetic effect can be positive for gap permeability, leakage flux can increase, and saturation can limit gains. These effects must be taken into account for a system optimized for ferrofluid immersion.IntroductionPermanent Magnet Machines (PMM's) convert electrical energy to mechanical energy in motor applications, or, for generator applications, convert mechanical energy to electrical energy through means of passing alternately polarized magnets past electrical coils. Looking at a simplified version of a PMM, where Rx is magnetic reluctance and <l>x is magnetic flux, we have the circuit shown in Figure 1."

Jan 1, 2013

By Józef Czernecki

The Polish copper concentrates are characterised by low content of sulphur and iron. At KGHM Polska Miedz S.A. two copper production technologies are in use. The shaft furnace process is used at the Legnica Copper Smelter and the Glogów I Copper Smelter. A single-stage direct to blister Outokumpu flash smelting process is used at the- Glogów II Copper Smelter. Melting copper concentrates in the shaft furnaces is carried out in a reducing atmosphere and the product obtained is a matte. Instead, a result of melting copper concentrates by an oxidising flash process blister copper of a quality similar to that of converter copper is obtained. The annual copper production at KGHM Polska Miedz S.A. exceeds 450,000 tons. Another important metal is silver produced from slimes from copper electrolysis (about 1000 t/y). Moreover, such metals as Pb, Ni, Se, As, Au and other precious metals, including Pt and Pd, are recovered from various semiproducts. This paper presents technological flow sheet of the copper production in plants using the shaft furnaces and in another plant in which a single-state flash process is applied. Characteristics of products, methods of their utilisation, main parameters of particular technological operations, and advantages and shortcomings of the solution applied are presented. There are also discussed: the natural environment protection as well as directions of the KGHM Polska Miedz S.A. plants modernisation.

Jan 1, 1999

By J. P. Ibáñez

The uptake of copper from extremely dilute aqueous solutions by alginate in the form of protonated dry alginate beads was investigated. Barium was used to cross link the alginate forming the beads. The effect of various experimental parameters such as pH and metal ions concentration on the uptake of copper were studied. The uptake was strongly dependent on the Cu-bearing solution pH up to a value of 4.5. A removal of 100% o was achieved when the initial concentration of copper was as low as 8.0 mg/L. The maximum uptake, i, e., the loading capacity, was found to be 167 mg of copper per g of beads. The mechanism governing the removal of copper was found to be ion exchange between protons of the alginate beads and cupric ions of the solution. For this ion exchange process a molar ratio, d[H+]/d[Cu2+], of 2.0 was determined. EPMA-EDX analysis of the Cu-loaded beads showed a uniform distribution of the ions throughout the structure of the alginate, regardless the solution pH. This may suggest that this sorbent material is a porous ion exchanger having high permeability and capacity. The uptake of copper and of the heavy metals cadmium and zinc by this sorbent is compared.

Jan 1, 1999

By Philip L. LeHoux

"Kennecott Barneys Canyon Mining Co. is a gold heap leaching facility that has been in operation since 1989. In 1994, a flotation plant was commissioned to remove sulphide minerals from refractory sulphide ore. Tailings from the plant are mixed with oxide heap leach material in order to produce a geotechnically stable agglomerate from which the gold is leached and recovered in a conventional heap leach cyanidation process. The experience to arrive at an effective blending methodology is discussed.IntroductionAgglomeration is the practice of binding fine particles to coarser rock or other fines in order to avoid the deleterious effects of mobilizing the fines during the course of heap leaching(l-Chamberlin). Agglomeration has been considered a key component of successful operation at many heap leach sites. If the ore is of sedimentary origin and crushed, there is a high likelihood that the resulting product will contain a significant quantity of fines and a skewed gradation, that i~, a disproportionate amount of coarse and fine particles, with few in the intermediate size range. The exact methodology for determining whether the practice of agglomeration will have to be integrated into the operating scheme has been well discussed. These conditions are primarily geotechnical and geochemical. This paper will deal with the specific experiences of Kennecott Barneys Canyon Mining Company in modifying the agglomeration practices to suit evolving operational requirements."

Jan 1, 1997

By Tejs Vegge

The lack of suitable means of storing hydrogen for use in the transport sector is generally viewed as a primary showstopper for a hydrogen economy. Recent developments within solid state hydrogen storage in complex hydrides and metal ammines have sparked new hope of a long term solution, but as of now, no materials fulfill all the DoE targets for onboard storage [1]. A detailed physical understanding of the ab-/desorption processes and the role of the essential catalytic additives is an essential prerequisite for the development of new optimized hydrogen storage systems. Here, we illustrate the potential of utilizing the synergy of combining state-of-the-art in theoretical methods and experimental techniques in the analysis and design of materials for hydrogen storage. Recent advances in computer hard- and software has made it possible to treat many of the essential problems in such materials, i.e. structural stability, hydrogen dissociation and diffusion, with high accuracy methods like density functional theory. We rely on such results to guide our synthesis of new materials, and to interpret our experimental results from, e.g. time dependant in situ x-ray diffraction, synchrotron/neutron experiments, and advanced materials testing. Through a continuous feed-back optimization loop between theory and experiments, the obtained nano-scale insight is used to expedite the design and development of novel materials for hydrogen storage.

Jan 1, 2006

By S. N. Ashrafizadeh

Nowadays, hard carbides have found various industrial application in the manufacture of cutting and drilling tools as well as metal forming devices. About 60% of the world tungsten production is consumed in the manufacture of hard carbide pieces. Regarding the high economic value of hard carbide components, i.e., Ni, Co, TaC, TiC, and WC, their recovery from scrap species is attracting much interest. In the current research, the cobalt and tungsten content were recovered from scrap cemented carbide pieces through the application of high voltage electrolysis in nitric acid media. By this method, cobalt and tungsten were initially recovered as cobalt nitrate and tungstic acid, respectively. The precipitate of tungstic acid was calcined at 800ºC after being washed twice with distilled water. A pure tungstic oxide was obtained. The effects of current density, electrolyte concentration, speed of agitation, and the surface area of the anode on the efficiency of the electrolysis process were investigated. The optimum conditions of current density of 1500 A/m2, an acid concentration of 1.5 M, and a cell temperature in the vicinity of 60 to 80ºC were obtained. At the optimum conditions, an acceptable rate of collapse for the anodic carbide pieces of about 3.1 g/h was achieved, which remained constant up to the completion of the recovery process without any passivation .

Jan 1, 2003