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By Seung-Chul Lee

Transparent conducting tin(1V) oxide thin films have been studies and developed for the electrode materials of solar cell substrate. Fabrication of tin oxide thin films by sol-gel method is process development of lower cost photovoltaic solar cell system. The research is focused on the establishment of process condition and development of precursor. The precursor solution was made of tin isopropoxide dissolved in isopropyl alcohol. The hydrolysis rate was controlled by addition of triethanolamine. Dip and spin coating technique were applied to coat tin oxide on borosilicate glass. The resistivity of the thin film was lower than 0.18-cm and the transmittance is higher than 90% in a visible range.

Jan 1, 1999

By A. Dell’Era, M. Pasquali, C. Lupi

"An electrochemical cell has been designed to treat very diluted cobalt solutions, i.e. those deriving from recycling processes of lithium-ion batteries. A reticulated vitreous carbon sponge was used as cathode and a Pt-coated Ti net as anode. A controlled potential electrolysis has been carried out in a solution flowing in the cell and maintained at a constant pH of 6.5. Considering the cathode dimensions (10.0 cm * 10.0 cm * 1.25 cm), rather high volumes of solution (>1 litre) can be treated with flow rates up to 1.6 l/min. The process yield is obviously related to the solution concentration; it has been observed that, starting with a solution containing 200 ppm of Co2+, the yield is initially ~35-40%, but it decreases to ~20% when 80% of the initial cobalt content has been electrowon. The yield increases up to ~50% if the carbon electrode is coated by cobalt. The conditions allowing a fast and complete removal of cobalt are outlined. Introduction Industrial liquid effluents containing heavy metal ions arise not only during hydrometallurgical processing, but also in many sector of chemical industries utilizing metal catalysts and process reagents. These waste solutions containing low quantities of metallic ions can be treated by chemical precipitation, solvent extraction, ion exchange, etc. before final discharge. All these techniques could be efficient for complying the aqueous effluents with the severe rules related to the environmental impact, but they can not directly produce metals. Particularly the chemical precipitation presents two main drawbacks, huge amount of sludge prodction and reagent costs to produce this useless and sometime dangerous sludge that have to be considered. Electrochemical technologies can be used for the treatment of effluents polluted by metal ions, showing the following advantages in comparison with other processes: 1. recovering of the polluting substances in metallic forms, with subsequent reusing; 2. absence of process slag, which should be subsequently disposed of. In this work an electrochemical reactor with a reticulated vitreous carbon cathode and a platinated titanium net anode has been designed and utilized for removal Co from waste aqueous solutions. Porous materials have been used as electrodes for this cell, as their high specific surface area favours the treatment of these low metal content solutions (1-7). This kind of electrodic material presents very interesting chemical-physical characteristics such as: low density, low thermal expansion and high electrical and thermal conductivities; particularly the reticulated vitreous carbon (RVC) presents a very elevated void volume, rigid structure, good resistance to temperatures in non-oxidizing environments and very low resistance to fluid flow."

Jan 1, 2008

Novel techniques were developed to obtain samples from and make measurements in the shaft of the flash furnace at the Kalgoorlie Nickel Smelter. The data obtained was used to validate mathematical models of the burners and the reaction shaft. Particle, gas and wall temperatures were measured along with the oxygen potential of the molten particles. Collected particles were characterised by sizing, chemical analysis and optical microscopy. The region of the shaft immediately beneath the burner where the rate of change was most rapid received special attention.

Jan 1, 1993

By Helena Byrdziak

KGHM Polska Miedz SA, in existence since nineteen seventies, operates three underground mines and three smelters with total production of over 400 000 mtpy of electrolytic copper. Its impact on the environment, very serious in the past, has been gradually reduced. While in general emissions into the air and water have been brought under control, attention recently has shifted to the disposal of wastes and residues. The main streams of wastes are flotation tailings, slags and dust captured from the dedusting systems. Much effort has already been expended and is still being spent to utilize this waste for by-products production or to dispose of it within the process by recycling. The most effective measures taken up thus far, as well as present activities directed at tailings disposal, are presented.

Jan 1, 1997

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 Tomas Astorga

APEC, the Asia Pacific Economic Cooperation is the forum of 21 countries having approximately 56% of the total world income, and over 45% of global trade. In 1997, APEC economies produced 67% of the world copper output, 55% of gold, and over 45% of other base metals. Mining in APEC captures more than 60% of the total mining investment in the world. New and emerging economies are now appearing in the demand scenery, such as China. New trends in the international environmental regulations are posing questions related to the use of copper in different industrial and consumption applications. These may have a strong impact on future trade of copper. New applications are also appearing based in new technology fields. The paper examines the growth potential of the copper market in main consumer ad highly populated economies of APEC, incorporating analysis of various interrelated factors. It also analyses the outlook of the copper supply. Its conclusions point to the need to implement demand outlook models. Finance and economic reforms will open important avenues for trade growth in basic metals, particularly copper. Changes in the consumption patterns of highly populated countries will add to better perspectives of copper demands. The recovery of a fast pace of economic growth in the APEC region will bring new demands for copper, especially as a consequence of high tech applications. More extended policies focused in the need for developing energy efficiency programs and schemes will add to this picture.

Jan 1, 1999

By Dong-dong Liu, Jian-ping Niu, Qi Liu, Shu-sen Cheng

A numerical model was developed to simulate the three-dimensional heat transfer in the belly and lower shaft region of the blast furnace wall consisting of copper steel composite stave, packing and shell. The temperature distribution of copper steel composite stave without the slag layer or refractory lining was investigated and then compared with the copper stave. The results showed that copper steel composite stave can satisfy the requirement of overheatingfree and had an analogous heat transfer behavior as copper stave but more stable cooling intensity. This model had been validated by the good agreement between the computed and measured temperature in the thermal test.

Jan 1, 2015

By Andreas H. Vassiliou

Organic materials are major constituents of the ore in several uranium deposits. Some of these deposits have been described as "urano-organic" because, the organic materials are believed to have provided the dominant control for the accumulation and deposition of uranium and are directly and intimately intermingled with the uranium. The nature of these urano-organic deposits has been problematic in terms of (a) the origin of the associated organic materials and (b) the specific form of' occurrence of uranium. The organic materials in urano-organic deposits have been genetically related to both coal and petroleum or their progenitors or deriva-tives. Analytical data presented here (infrared, chemical. D.T.A.) suggest that coaliferous materials or related plant derivatives represent the main source of the organic fractions in practically all major urano-organic ores analyzed from the Colorado Plateau and other areas. Recognition of the specific form of occurrence of uranium in urano-organic deposits has been problematic mainly because the uranium is usually in an extremely fine-grained and disseminated state in the organic matrix. Electron microprobe and X-ray diffraction analyses presented here show that fine-grained uranium minerals, specifically uraninite or coffinite. are disseminated in the organic matrix as the predominant form of uranium in most major deposits; however. the presence of true organo-uranium compounds is also suggested for some deposits.

Jan 1, 1981

By C. Lupi

In 1996 the Italian Agency for Environmental Protection (ANPA) has initiated a study of the environmental impact of the industrial sector of steel produced by Electric Arc Furnace (EAF). Within the framework of this study a hydrometallurgical process to treat EAF dusts was considered and developed. The paper describes the zinc and lead recovery from fumes coming from carbon steel production. The zinc extraction consists in acidic leaching followed by SX-EW steps. The leaching sludge containing lead sulfates was treated to obtain pure lead salt and inert solid residue. The whole process, that minimizes effluents by recycling the main liquid streams, has been developed to obtain marketable products. The solid waste, containing spinels, was subjected to elution tests in order to verify its compatibility with environmental regulation. The process, that has been set-up and tested in the laboratories of the University of Rome, will be transferred and studied on a pilot plant in order to assess its industrial and economical feasibility.

Jan 1, 1999

By John Fallavollita

Conventional gas atomization produces powders that vary widely in size distributions and microstructures, thus making it very costly to produce powders tailor made in a narrow size distribution and microstructure. Furthermore, it is difficult to determine the relationships between atomizer operating conditions and resulting powder characteristics. The Impulse Atomization Process (IAP) was developed at the Advanced Materials and Processing Laboratory to produce powders with narrow size distributions. Powders produced by the IAP were reproducible and their sizes could be easily controlled by adjusting experimental conditions. Characteristics of Zn, Sn-Pb, AI-Cu, and Cu powders will be described to illustrate the flexibility of the process to tailor-make powders.

Jan 1, 1994

By G. Diáz

The PLACID process applied to the recycling of spent lead-acid batteries is being developed by an European Consortium within the Brite-Euram II programme. The status of the project entitled "Lead Recovery from Lead Oxide Secondaries" is described in this paper. The main laboratory and batch experimental results and the preliminary feasibility study are summarised. The description of the demonstration pilot plant and continuous campaigns programme for 1995 are also included. An interesting global approach is proposed, integrating the Placid process in the existing spent battery recycling pyrometallurgical facilities. This yields important improvements in the overall process. Grids would be easily treated by the conventional pyrometallurgical route, obtaining lead alloys,, while battery pastes, slags and fumes would be fed to the Placid process, obtaining pure electrolytic lead (>99.99 %), ideal for battery paste manufacturing. The implementation of the Placid process into the existing battery recycling pyrometallurgical facilities is analyzed from technical, environmental and economical viewpoints. Greater overall lead recovery, lower operating costs, reduced waste production, environmentally safer residues and much better lead product quality are the key advantages. The authors draw the following final conclusion : Integration of the Placid process with conventional pyrometallurgical treatment is a feasible and very attractive alternative route for spent lead-acid battery recycling.

Jan 1, 1995

By Alan J. Hurd

"New insights into the development of microstructure in sol-gel films have recently been revealed by several diagnostic techniques, including imaging ellipsometry, ""chemical imaging"" by fluorescent tracers, light scattering from capillary waves, and finite-element modeling. The evolution of porosity during the continuous transition from dilute sol to porous solid in restricted geometries such as films and fibers is becoming clearer through fundamental understanding of evaporation dynamics and capillarity.IntroductionWith sol-gel processing, the full flexibility of solution chemistry can be exploited to make ceramic films and fibers with well controlled compositional characteristics. No less important is the ability to tune porosity and connectivity for specific applications such as optical and electrical coatings and membranes. Since the chemical and physical factors that determine the microstructure are not entirely understood, new diagnostics applied to sol-gel processing are welcome.Sol-gel films and fibers are distinguished by processing that takes a sol through continuous stages of increasing concentration and connectivity of a solid precursor. The liquid carrier is usually volatile or, at least, volatilizable through heat treatment. During deposition through states of increasing solids concentration, this sol might gel, as in bulk sol-gel processing, however, the gel state may be a fleeting transient that quickly empties of liquid. Nevertheless, the structures formed in solution during this stage influence the structure of the final solid. In particular, porosity is likely to be a remnant of networks formed in the sol-to-gel transition. Here we report on experiments whose goal is to discover the factors involved with porosity development."

Jan 1, 1994

Designing rigging systems for complex castings has been more of an art than a science. Foundrymen have used thumb rules based on past experience to develop working designs. Of late, attempts are being made to formalize the procedure through the use of rule based expert systems, process modeling and other tools. Designing risers is one of the challenges of the rigging system design. Once the riser location have been determined, an optimization technique coupled with a casting simulation code can be used to determine the optimum riser dimensions. The main drawback of using a finite element or a finite difference based process simulation code along with the optimization routine is that the computation time involved is too large. Such an approach, thus, is unrealistic for practical situations where different options have to be explored and conclusions drawn in a short period of time. This difficulty has been avoided in the present work. The optimization scheme has been coupled with a modulus based solution routine to optimize the riser dimensions. The modulus calculations provide a good and quick estimate of the freezing time at different points in the casting. A functional, obtained from these freezing time values, is minimized by altering the dimensions of the riser until an optimum shape is obtained. Some examples have been included to illustrate the utility of this technique.

Jan 1, 1994

By Wolfgang Steffes-Tun

Pyrite ore concentrate from the Meggen mine (FRG) , which contains about 0 300 400 ppm thallium, is roasted in a fluid bed furnace at 1000 -1100 C to form sulfur dioxide and ash consisting mainly of hematite. Subsequently, the sulfur dioxide is separated from the ash or dust during several steps while cooling to about 250oC. The pyrite ash fractions show decreasing grain size down to 5 pm, a pH-decrease down to 2,4 and a marked enrichment of arsenic and thallium by a factor of 12. In the final fraction, the hot electroprecipitator dust of the dump (EGR), minute crystals of thallium-containing jarosite can be detected by analytical transmission electorn microscopy (TEM). Under oxidizing, acid conditions, jarosite may be a possible "reservoir mineral" for immobilizing thallium.

Jan 1, 1989

By C. H. Tsau

The intermetallic compounds of Ni-25Al-xFe, x is 20-40 at.%, were prepared by arc melting and drop casting into ingots, and were rapidly solidified into ribbons by melt spinning. The microstructure evolution of these alloys with varied Fe content were examined by the x-ray diffraction, optical microscope, scanning electron microscopy and transmission electron microscopy. The results reveal that two phases, {y'} and {B} phases, are existing in the alloys with low Fe content, and the microstructure changes from the mixture of y' and {B} phases to a single 0' phase when the Fe-content reaches to 40 at.%. Also, the formation of y' phase will be suppressed by rapidly solidified process. For annealing both of the melt-spun and the cast specimens, a disorder 0 phase was revealed in both of the ribbon and the cast ingot of Ni-Al-Fe alloys with higher Fe content. In addition, increasing the increment of iron which substituting nickel in this alloys results in increasing the lattice parameter of both {y'} and{B} phases.

Jan 1, 1992

By A. V. Tarasov, V. M. Paretsky

"The design is based on the thermal processing of the wastes in· the intensively bubbled melt in the Vanyukov furnace at the relatively high temperatures (1350- 1450 °C), In this case: -the secondary wastes are not formed; - the especially toxic substances at the outlet from the furnace are absent. The technology was tested on a large scale (on semicommersial bases). Technical and economical basis show profitability of recovery complex for processing of hard garbage waste (HGW) using this technology: the period of capital, investments refunding for the, recovery, complex construction with process annual capacity of 240 thousands tons of wastes is 1,5-2,5 years,"

Jan 1, 2000

By Rollie E. Dutton, David A. Stubbs

"A sensor has been developed and tested that is capable of emitting and receiving ultrasonic energy at temperatures exceeding 900°C and pressures above 150 MPa. The sensor works with standard ultrasonic pulser-receivers and has demonstrated the capability of measuring workpiece deformation during hot isostatic pressing (HIP). Details of the sensor design, performance, and coupling of the ultrasound to the workpiece are described. Ultrasonic data acquired by the sensor, in situ, during HIP runs and at elevated temperatures in air are presented.INTRODUCTIONHigh temperature structural components, such as structural castings for jet engines, nickel-base superalloy turbine blades, and ceramic and metal matrix composites made from powders are often densified by hot isostatic pressing (HIP). For powder consolidification, the HIP process involves sealing the powder (and reinforcing fibers for composites) within an evacuated ""Can"" made of a material that softens at high temperatures. A hydrostatic pressure is then applied by pressurizing the inside of the HIP vessel with argon gas (up to 140 MPa). The hydrostatic pressure densities the powder through the elimination of the porosity between the powder particles.This paper presents details of the development and preliminary testing of an ultrasonic displacement sensor that can be used to monitor materials processing, in situ, at temperatures and pressures significantly higher than current ultrasonic displacement sensors. The target processing environment for this sensor is that typically found in a hot isostatic pressure (HIP) vessel, i.e., temperatures exceeding 1000°C and pressures above 138 MP a."

Jan 1, 1997

By P. Balachandran

The paper outlines the existing facilities and working practices at the Khetri electro-refinery of Hindustan Copper Limited. Plans have been drawn up to mechanize some key operations to improve the quality of cathodes and the working environment as well as economize the refinery operations. The economic analysis for determining various optimum operational parameters under conditions existing in India have also been outlined. The impact of capacity utilization and mechanization under different sets of conditions on operational costs have been highlighted.

Jan 1, 1987

By Miller, Geoffrey W.

The Ravensthorpe Nickel Project (RNP) flow sheet provides for the upgrading of Ni & Co in a size based beneficiation process prior to leaching. The upgrading effect on Ni and Co makes the beneticiation process a powerful addition to the flow sheet. Multiple linear regression (MLR) analysis based on 351 individual batch tests, 52 large scale composites and 21 pilot plant tests has been used to successfully model beneticiation product grade, recovery, upgrade and mass recovery. Statistically, 83% and 96% of the variability in nickel recovery and nickel product grade respectively was accounted for. Algorithms have been developed for Ni, Co, Mg, Al and Fe, which represents the revenue and operating cost factors for the process. The algorithms have subsequently been applied to the resource model, allowing prediction of elemental grade and recovery for the development of the mine schedules based upon these parameters and not head grades alone. This has allowed optimisation of the mine schedule for improvement to the project's NPV. Keywords: Ni Laterite, Prediction, Multiple Linear Regression, Beneficiation

Jan 1, 2004

By R. D. Osmanson

A series of batch roasting tests was performed on minus 1/2 inch gold bearing refractory samples from the Gold Acres deposit, and 67 select particles were polished and the sulfide alterations were examined microscopically. The suite of specimens represents two hour batch roast treatments at 600°C, 700°C, 725°C, 750°c, 800°C, and 900°C. Auriferous pyrites were found to alter sequencially to pyrrhotite, magnetite and finally to hematite. It was found that the decrease in cyanidation extraction with high temperature roasting is likely due to the increas ing stability of magnetite and more crystalline hematite, and the decrease in porosity with these phases which occlude the gold. Gold has been noted to occur very early in the mineralizing sequence, with gold being found in quartz and in clay/carbonate rock matrix. No gold was found in the two pyrite phases, but numerous gold grains were found in pyrrhotite after pyrite and in subsequent iron oxides. Gold mineralization had apparently ended by the time base metals were introduced into the deposit.

Jan 1, 1987