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By William Bourcier

Geothermal Brines are a significant potential source of valuable minerals and metals. These brines are water that is heated by the natural heat flow from the depths of the earth. Hotter brines, typically with temperatures greater than 120°C, are used to generate electricity. Lower temperature brines are directly used to supply thermal energy to applications such as agriculture, aquaculture and process/domestic heat. The geothermal waters have had intimate and lengthy contact with the layers of the earth?s crust that they flow through, resulting in dissolution of minerals and metals from the rocks, and solution into the hot water. These aqueous solutions can be processed to recover minerals and metals. Some potential products include silica, zinc and lithium, along with other materials. Recovery of minerals and metals from geothermal brines can be viewed as ?solution mining by nature?, followed by application of known or new hydrometallurgical techniques for isolation and purification. This paper discusses the opportunities, the processes, the challenges, the current status, the economics and the potential for recovery of minerals and metals from geothermal brines.

Jan 1, 2006

By Suswnu Makino

Sumitomo Metal Mining developed a new nickel refining process ( Matte Chlorine Leach Electrowinning process) based on chlorine leach and electrowinning technologies. After the pilot plant study, the commercial plant with design capacity of 24,000 tonnes per year was constructed and has been successfully operated since August, 1992. During the practice of the past three years, great deals of improvement have been achieved. Through these operations the MCLE process has been demonstrated to be one of the most superior processes in the world with nickel recovery, productivity, cathode quality and working environment. Today the refinery product capacity is increased to 30,000 tonnes per year. This paper describes the equipments and operation of the Sumitomo MCLE process.

Jan 1, 1996

By Roland Kammel

In combination with various physical and chemical methods also electrochemical techniques are most frequently used to improve the recovery of metals from aqueous dilute process streams or effluents e.g. in electroplating, metal finishing, mining and metallurgical plants. To insure cathodic metal recoveries with favorable current efficiency and high throughputs per unit of cell volume seve¬ral types of electrolysis cells have been developed comprising extended electrode surface areas and/or intensive electrolyte. agitation. The practical experiences with these units indicate especially for the electrolytic recovery of metals whose values are high, that the treatment cost permits profitable operations with relativly short payback periods for the units. Anodic reactions can be utilized for the removal of undesired anion contents or buildups of impurities. Appropriate combinations of these recovery methods are used to improve the versatility and the overall economy. Industrial applications reveal their potentional as addidtive techniques for existing processes to reduce the metal content of effluents to values that meet the guide lines of environmental legislation whereas integrated in-operation recovery methods are nowadays increasingly introduced to approach nearly close-loop operations.

Jan 1, 1992

By Larry G. Stolarczyk

The development of geosteering technology for geothermal reservoirs is challenged by the integration of electrically small antennas in small-diameter metallic drill rods. To be useful, the antenna pattern must achieve sufficient back-lobe suppression, preferably with a forward-looking pattern. Forward-looking capability requires an antenna array with phase control. The phase-controlled antenna pattern enables imaging of geologic structures ahead of and surrounding the well bore. This paper describes the development of electric and magnetic dipole arrays for small-diameter drilling pipe.

Jan 1, 2006

By M. Hadj Meliani

This paper explores direct use of finite element analysis by CASTEM 2000 in order to determine the evolution of T-stress term for arc of pipe specimens with external surface crack. A simple method, called the stress difference method proposed by Yang (1999), is used to compute the elastic T-stress in mode I at a crack tip. The different crack geometries and length-to-thickness ratio on T-stress and stress-intensity factor (SIF) are examined. The revisited stress difference method is shown to be an accurate and robust scheme for evaluating T-stress in arc of pipe.

Jan 1, 2006

By M. C. Ruiz

The leaching behavior of chalcopyrite concentrate in acidic CuC12-NaCI-O2 solutions was investigated. Experiments were conducted under continuos flow of oxygen at atmospheric pressures. The results indicated that among the variables temperature has the largest influence on the dissolution of chalcopyrite in this medium, and high copper extraction can only be obtained at temperatures near the boiling point of the solution. It was also found that the stirring speed did not influence appreciably the dissolution of chalcopyrite. An increase in the oxygen flow rate up to 0.1 1/min increased the copper extraction. The total chloride concentration affects the dissolution of chalcopyrite up to about 4 M. Copper extraction of 93 % was obtained in leaching chalcopyrite of size fraction -400 # Tyler at 105 OC in 2 hours.

Jan 1, 1997

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 Steven C. Torma

The present article reviews some of the technologies available for recycling high-energy yield explosives loaded projectiles. These activities lead to reduction of military ammunition stockpiles and their conversion into commercial and industrial applications. The recycling technologies involve dismantling and separation of ammunition components into recyclable metals, plastics, paper and explosive materials. The metal 1 ic components will be sent to smelters, where they will be converted to products that can be used in a variety of industries, such as construction, automotive, housing and so on. Plastics and paper will be recycled and reused. Explosives will be recycled to be used for industrial purposes in the mining industry. Propellants (ammonium nitrate and ammonium perchlorate) can be ground to small particle size and treated to be used in the agricultural industry as fertilizer. In addition, some of the excess explosive material recovered in the demilitarization process may be incinerated to produce energy for steam production for heating purposes, or for production of electricity. Furthermore, this article reviews the developments in the bioremediation of explosive contaminated soils and industrial effluents.

Jan 1, 1994

By P. A. Botha

The coal seams in the Waterberg basin occur in correlates of the Vryheid and Volksrust Formations as developed in the main Karoo basin. In the Vryheid Formation, five thick seams of predominantly dull coal are present, whereas a multitude of thin, lenticular seams (a few millimetres to 2 metres}, predominantly of bright coal, are developed in the overlying Grootegeluk Formation. During exploration, the coal seams were divided into 11 zones. Analytical data on float and middlings fractions (RD less than 1.40 and between 140 and 1.80, respectively} were used mainly for stratigraphic correlation of the zones in the Grootegeluk Formation. The affinities of the major and trace elements for different mineral phases and/or organic material are discussed on the basis of correlation matrices and vertical variation diagrams. Titanium and vanadium clearly show some degree of organic affinity. P 205' AI203 and alkaline-earth elements are also positively correlated by the presence of goyazite in the coal. This type of investigation gives an indication of the degree to which undesirable elements like P and S can be removed during coal beneficiation, of which coal zones are unsuitable for the production of metallurgical coal on account of a high content of these elements, and to what extent the blending of different coal zones is required to keep the concentration of these elements within acceptable limits.

Jan 1, 1991

By T. K. Mukcherjee

The importance of the processing of secondary resources such as solid industrial wastes and liquid effluents as well as byroducts for the recovery of the associated metal values hardly needs any elaboration. Such processing contributes in no small measure.towards the augmentation of the availability and the supply position of resources. As an added benefit, it leads to a reduction in environmental pollution caused by the undesirable waste materials. As some typical examples of secondary resources in the Indian scenario, mention' can be made of spent catalysts, metal/alloy scrap, ash, consumed batteries, flue dust, slag, sludge and slime, pickling solutions, spent acids; plating rinse solutions, spent etchants, waste water from synthetic fibre manufacture and from tanneries etc. These wastes constitute a source of a variety of non ferrous metals. In the processing of secondary resources like these, the techniques of hydrometallurgy such as solvent extraction play a pivotal role. This paper outlines the efforts made to use solvent extraction to recover(1) base metals. such as copper, zinc, nickel and cobalt from a number of secondary resources like cake, and sludge(2) refractory metals like molybdenum and vanadium from sulphidic byproducts and spent catalyst and (3:) nuclear metal like uranium from phosphoric acid. In the case of base metals, process flowsheet involving the use of acidic extractants such as DEHPA and PC88A have been optimised. The problem of iron removal from the leach liquor, "which influences the metal recovery process significantly, has drawn a special emphasis. hi the case of refractory metals, basic extractants .like Alamine 336 has been pressed into service to produce kilogramme. quantities of pure salts of molybdenum and vanadium, Finally, the paper gives a brief account of plant experience in recovering uranium from phosphoric acid, using 'a solvent system comosed of DEHPA and TOPO.

Jan 1, 1996

By Satoshi Itoh

Phase equilibria and activities of the components in the liquid lead-antimony-oxygen ternary system, which is of fundamental importance for discussing the' recovery of lead and antimony from a used lead-battery, have been investigated at 1173 and 1223 K. The two liquid phases of metal and oxide were observed at the temperatures studied, and the tie lines indicating isoactivities were determined. The activities of PbO, SbO1.5 and Sb2O3) in the PbO-SbO1.5 and PbO-Sb2O3 pseudo-binary systems were then obtained by applying the Gibbs-Duhem equation to the phase relation of metal-oxide equilibrium. Both in the pseudo-binary systems the activities exhibit negative deviations from Raoult's law. The vapor pressures of lead, antimony and lead oxide, antimony oxide were calculated by using the activities of the components in the lead-antimony-oxygen ternary system. As a result, an oxidation of antimony concentrated in an anode slime followed by evaporation as antimony oxide Sb406 was found to be considerably effective for the recovery of lead and antimony from a used lead-battery.

Jan 1, 2003

By K. Krishnapisharody

A mathematical model has been developed to predict the interface dynamics and droplet generation of the buoyant phase in a two-fluid system. The model employs the well-known SIMPLE algorithm for obtaining flow fields and the Volume of Fluid (VOF) method, for interface tracking. The implementation of the model in water-oil systems, where the oil layer is placed above a recirculating water bath, is discussed. The evolution of the water-oil interface leading to the formation of oil droplets is computed realistically.

Jan 1, 2008

By J. M. Casas

This work presents the development of an ionic equilibrium model and its use to simulate the distribution and concentration of chemical species (speciation) in sulfuric acid - cupric sulfate solutions in the 0-2 pH range, 0.1-10 gpl copper concentration range and 15-45°C temperature range. The model consists of a set of equations which represent the equilibrium relationships for the ionic reactions and the mass balances for the components present in the system. The effect of ionic strength was taken into account by correcting the equilibrium constant in concentrated solutions. Several species can be formed at different pH and temperature values, the principal being: HSO-4, SO42-, CuSO4(aq), Cu2+, and H+ in order of increasing solution acidity. Simulations show that concentrations are highly dependent on pH. The sulfuric acid speciates mainly as bisulfate ion (HS0-4) and hydrogen ion (H+) at pH values lower than 1. The model presented in this work can be applied to predict and analyze the solution composition in electrolytic copper processes such as electrowinning, electrorefining and electrodialysis, as well as the purification of various industrial solutions.

Jan 1, 1999

By Manolete Mena

WC-Co nanocomposite powder is among the first group of materials with a promising potential for nanocrystalline-materials application. A chemical vapor synthesis (CVS) process that has previously been used for preparing the aluminides of titanium and nickel, and other metallic and intermetallic powders has been applied to the preparation of WC-Co nanocomposite powder. This CVS system was designed so that a tungsten precursor (WCl6 powder) and a cobalt precursor (CoCl2 powder) were separately fed into each evaporator in a reactor by means of specially designed powder feeders. The reduction and carburization of the vaporized chlorides by methane-hydrogen mixtures produced nanosized WC and Co composite powder. The product is a very uniform mixture of the constituent powders, which is important to ensure a high quality of the bulk cemented tungsten carbide product after consolidation. In the present work, the effects of reaction temperature, CH4 to WCl6 ratio, CH4 to H2 ratio, residence time, and Co content on the powder composition and particle size were determined. The products were characterized using XRD, carbon analyzer, and TEM.

Jan 1, 2006

By Onuralp Yucel, Ahmet Turan, Halil Yildirim

"Nickel is mainly used in stainless steel production as ferronickel. In recent years, low grade ferronickel or nickel pig iron (NPI) is used in stainless steel production to reduce expenditure of nickel price. In this study, Turkey East Anatolian region lateritic nickel ores were directly introduced carbothermal reduction to produce NPI. Firstly the raw lateritic ore that contains 0.9% Ni, 0.054% Co and 2.3% Cr was mixed with metallurgical grade coal at different stiochometric ratios. The samples were smelted at 1600-1650 °C temperature range in an induction furnace for 25 min. In the second experimental set, different processes times were carried out from 15 to 35 min. The raw material, obtained alloys and slags were analyzed by using XRD (X-Ray Diffractometer), XRF (X-Ray Fluorescence Spectrometer), AAS (Atomic Absorption Spectrometer) and EPMA (Electron Probe Micro Analyzer) techniques.IntroductionNickel is an important element that has many application areas in the industry and there are a lot of kinds of nickel products such as refined metal, powder, sponge etc. 65% of metallic nickel is used in stainless steel, 12% is consumed as superalloy and non ferrous alloy because of its superior corrosion and high temperature properties [1].Nickel is a transition metal that is mined from mainly two types of ore deposits as sulphide ores and lateritic ores. Although 73% of nickel ores are laterites, 55% of primary production is from sulphide ores [1, 2]. The importance of lateritic ores is increasing due to the increase in nickel prices and decrease in reserves of sulphide ores.There are pyrometallurgical, hydrometallurgical and combined (pyro-hydrometallurgical) methods which are used for the extraction of nickel from lateritic ores. HPAL (High temperature pressure acid leaching) is generally used to recover nickel and cobalt from laterite nickel ores. It is suitable for the plants processing ores with low magnesium oxide and aluminum oxide content. Lateritic ores are exposed to hot acidic leaching around ~250 °C to dissolve cobalt and nickel under high pressure. The main disadvantage for HPAL is the high cost of titanium autoclaves. Process is complex and difficult to control due to the high pressure and heating of the process [2, 3 and 4]."

Jan 1, 2012

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

A recent survey of major steel companies worldwide revealed the importance of recycling zinc units from electric arc furnace (EAF) dust, mill scale, blast furnace dust and other zinc containing streams within the steel industry. Many processes have been developed and installed in response to this challenge. The most successful approach involves the production of a crude zinc oxide and its sale to primary zinc producers to recover the metal values. 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 the corrosion problems it will cause in electrolysis. In 1999, Big River Zinc installed a zinc oxide receiving and washing plant to minimize the impact of halides in its electrolysis circuit. A description of the washing plant and the initial operating results are presented in this paper.

Jan 1, 2000

By Manolete Mena

WC-Co nanocomposite powder is among the first group of materials with a promising potential for nanocrystalline-materials application. A chemical vapor synthesis (CVS) process that has previously been used for preparing the aluminides of titanium and nickel, and other metallic and intermetallic powders has been applied to the preparation of WC-Co nanocomposite powder. This CVS system was designed so that a tungsten precursor (WCl6 powder) and a cobalt precursor (CoCl2 powder) were separately fed into each evaporator in a reactor by means of specially designed powder feeders. The reduction and carburization of the vaporized chlorides by methane-hydrogen mixtures produced nanosized WC and Co composite powder. The product is a very uniform mixture of the constituent powders, which is important to ensure a high quality of the bulk cemented tungsten carbide product after consolidation. In the present work, the effects of reaction temperature, CH4 to WCl6 ratio, CH4 to H2 ratio, residence time, and Co content on the powder composition and particle size were determined. The products were characterized using XRD, carbon analyzer, and TEM.

Jan 1, 2006

By James C. Foley, David K. Rehbein

"In-situ characterizations of green state part density and sintering state have long been desired in the powder metal community. Recent ·advances in non-contact electromagnetic acoustic transducer (EMAT) technology have enabled in-situ evaluations of the acoustic attenuation and velocity as sintering proceeds. Pure aluminum (99.999%) and aluminum alloy powders were prepared with high-pressure gas atomization (HPGA). The powders were pressed in a uniaxial die and examined with acoustic waves for changes in velocity and attenuation during sintering. The changes in acoustic properties were correlated with sample microstructures and mechanical properties. Evolution of the acoustic echo train during sintering is shown to provide information on the state of sintering as well as having the potential for detection of interior flaws.IntroductionThe versatility of powder metalallurgy (PIM) technology in the manufacture of complex shapes has enabled an increasing amount of wrought and casting production capacity to be converted to PIM technology. However, ultrasonic inspection of green components produced using PIM techniques remains a challenge and is not generally practiced [1]. Inspection of PIM components in the green state is highly desirable, because the green part can be reclaimed with only accepted components being subjected to further costly processing. Another potential benefit is characterization and greater understanding of the sintering process itself. An increased scientific understanding of the sintering process enables intelligent process control, greater reliability of the production process and a lower rate of rejection of the finished product. In order to realize these potential benefits, it is necessary therefore that accept/reject criterion be based on real time nondestructive evaluation of the green-state components and the sintering process.Most current nondestructive inspection techniques suffer from their inability to perform inspections below the near-surface region with the exception of X-ray and to some extent pulsed eddy current [2]. X-ray inspection requires extensive shielding of production personnel and expensive film and film processing. While development of pulsed eddy current techniques have lessened the impact of the well-known skin effect, the depth of penetration of the induced eddy currents remains somewhat of an issue [2]."

Jan 1, 2000

By Hidenori Okamoto, Katuto Itoh

"Nippon Mining & Metals' Hitachi Refinery refines 40% of the anodes produced at its Saganoseki Smelter & Refinery. Its current annual production stands at 180,000tons.The refinery always endeavors to increase productivity. One of the outcomes of its efforts is an originally developed automatic short-circuit detector used to inspect short-circuits between anode and cathode. The detector is designed to inspect the 56 pairs of anode and cathode in a cell by fluxgate sensors at once. It inspects 564 cells, automatically and un-manned, and gathers data to be put into a computer. The development of the detector led to a reduction of man-power and achieved a detection accuracy superior to that of a hand-held gauss-meter. In addition, statistical and historical processing of the data enabled early detection and early recovery of the cells with poor efficiency.The new system also contributed to raising the refining capacity and reducing the unit steam consumption, because it is possible to inspect even the cells covered with thermal insulation sheets.IntroductionInspection of cells is an important component of the operation management of a tank-house. At the Hitachi Plant, it used to be carried out by two workers who walked on and checked all the cells of its tank-house once a day to find out any short-circuits in the cells, using hand-held gauss-meters. They inspected about 33 thousand pairs of cathodes and anodes a day and removed nodules by hammers. This method had following problems:it needed much manpower.the walk on the cells sometimes deranged electrodes positions.there was radiation-loss connected with the inspection due tothe fact that the workers were obliged to uncover thermal insulation sheets on the cells while inspecting."

Jan 1, 2000

By S LeClair

Intelligent manufacturing involves intelligent, product-directed systems that facilitate the on-line, real-time generation of an improving product process cycle. A first step in the journey relates to self-directed systems which have the ability to reason and create their own processing paths in response to varying product and process conditions encountered during the process. This paper discusses an application of self-directed process control in the manufacture of graphite-epoxy laminated composites. An Air Force team involving researchers and production personnel have caused the development of a system now in use at the Air Force Logistic Center at McClellan Air Force Base in Sacramento CA. The paper discusses results and lessons learned in the process of trying to speed the implementation of research efforts which show significant potential of improving the product quality in less time and at less cost

Jan 1, 1992