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By E. N. Mounsey

Ausmelt Technology was selected by Bindura Nickel Corporation (BNC) as the basis for a new copper circuit to process nickel plant copper leach residue to blister, anode and finally cathode copper and recover PGM values at the Bindura Smelter Refinery (BSR). The process selected, based on Ausmelt Technology to smelt and convert the residue to matte and blister copper and produce a discard slag, is novel incorporating smelting, converting and slag reduction process steps in a single Ausmelt vessel. The process demands a high quality blister copper product with low levels of arsenic and nickel. This paper reviews the project and the initial operational results to the end of 1997 of the Ausmelt Top Submerged Lancing (TSL) smelter and discusses the implications for the wider TSL converter market.

Jan 1, 1998

By Kent D. Peaslee

When supersonic oxygen jetting is used in electric furnace steelmaking, the lance jet axis is typically inclined at larger angles to the vertical than is used in basic oxygen steelmaking. The supersonic jet is important not only for refining the steel, but for sustaining the foamy slag in the electric furnace. Physical modeling was carried out using a room temperature, two-dimensional slice apparatus in which mercury represented the metal and water-glycerol the slag. High speed video photography with image analysis was used to study the effects of the angle of inclination on the slag/metal bath. Mathematical modeling using FLUENT provided a method of predicting flow patterns and the trajectories of drops injected at various points in the flowfield. A one-half scale water model of the system, in which lance heights, angles, and flowrates simulated those encountered in steelmaking operations, was used to provide a better understanding of some aspects of the oxygen blowing process in electric furnace steelmaking.

Jan 1, 1994

By L. Klinger, T. Werber, LA Levin, A Katsman

"The process of catastrophic carburization known as ""metal dusting"", whereby a solid metallic material is converted into fine particles in a carburizing atmosphere, was analyzed. It was shown that this conversion is the result of plastic deformation and subsequent fracture accompanying diffusional phase formation in the near-surface layer. The process is controlled by internal stresses arising during phase transformation. Competition between stress generation and relaxation may result in the attaining the ultimate strength in the near-surface layer and its fracture. Such a mechanism of metal disintegration may occur in a certain temperature interval depending on the kinetic and geometrical parameters of the system - the diffusivities of the alloy's components, the ratio between specific volumes of the new and the old phases, and the ultimate plastic strain. The temperature interval for disintegration of carbon steel, the rate of disintegration, and the period of the disintegration cycle, were evaluated and compared with experimental data. IntroductionCatastrophic carburization, known as ""metal dusting"", consists in conversion of a solid metallic material into fine particles. The process occurs in a carburizing atmosphere at elevated temperatures. The corrosion product, usually named ""coke"", consists of metallic particles dispersed in a loose carbon matrix. Under industrial conditions metal dusting takes place, for example, in a gas mixture of CO and H2 or in hydrocarbon environments. Steels, nickel- and cobalt alloys are susceptible to this kind of wastage in the temperature range 400-800°.A mechanism of metal dusting in steels was proposed by Hochman [1] and later developed by Grabke and coworkers [2-5]. According to the proposed model, the process consists of the following reaction steps:"

Jan 1, 1996

By K. Dzieciol

The paper presents a study about three image correlation methods ?common cross-correlation, mutual information and phase-correlation ? applied to characterize microstructures reconstructed with X-ray tomography. It is shown that phase correlation is not only the fastest, but also the most sensitive method for detection of similar microstructure features, cavities in the present case. A new image correlation indicator is proposed, which takes into account both the phase shift and the amplitude of similar features in compared images. Some preprocessing aspects related to the tomographic reconstruction and filtering out of characteristic noise are also discussed.

Jan 1, 2009

By Ben Q. Li

An efficient numerical algorithm for solving steady state heat transfer and solidification problems is described. The algorithm is of boundary integral type and is based on the formulation of the field variables along the boundary of the domain of interest. Compared with the familiar domain-based methods, such as the finite element and finite difference (or finite volume) methods, this boundary-based method has an advantage of solving fewer unknowns and hence has a potential for reducing computational time significantly. Another and yet more important advantage of the present algorithm is that it is a stable scheme and is not prone to numerical oscillations resulting from convective effects, as often encountered in the domain-based methods. Therefore, no numerical or artificial diffusion (such as streamline upwinding) is necessary. Numerical examples are presented that are drawn from processing systems for producing aluminum-based materials.

Jan 1, 1994

By M. Okido, H. Yamamoto, T. Sakamoto, R. Ichino, K. Kuroda

"Hydrogen absorption alloy films have been produced by molten salt electrolysis. Lanthanum-Nickel alloy film can be formed on a nickel substrate in KCl-NaCl-LaCb molten salts by electrolysis diffusion process. LaNi5 alloy was formed by mutual diffusion between La ·and Ni after La deposition on Ni substrate. Though several kinds of La-Ni compound existed in deposits, the alloy compounds on Ni substrate changed by electrolysis condition. According to the open-circuit potential measurement in molten salts after La electrodeposition, the formed compounds had a relation to the potential. In the case of the substrate electroplated a cobalt thin film on nickel, LaNi4_5Co0.5 was formed by the electrolysis in the molten salts with lanthanum ions. This ternary alloy film showed better hydrogen absorption behavior in cyclic charge/discharge test in alkaline solution.IntroductionHydrogen storage alloys have attracted attention as the active materials for batteries with the charge/discharge property at ambient temperature. The alloy of nickel and misch metal, mainly consisting of La and Ce, has been commercially 'used as a metal hydride with rechargeable property. In recent years, researches have been developed many kind of new alloys with better hydrogen absorption properties. The hydrogen absorbing alloy ingots are commonly produced by melting method of both metals in furnace, otherwise, prepared by mechanical grinding and metallurgical sintering technique with metal powders. The film is also made by vapor-phase techniques such as sputtering method, ion plating method, etc. ·We have proposed a new method to produce hydrogen absorbing alloy films by molten salts electrolysis technique [1-3]. The hydrogen absorbing film, LaNi5, Mg2Ni and CaNi5, were obtained in this process through controlling the electrolytic condition. The active metals, La, Mg and Ca, are electrodeposited on Ni substrate, diffuse into the substrate and form various kinds of intermetallic compounds. This technique provides a direct process using metal chlorides as resources to produce functional films without using active metals such as La, Ca and Mg."

Jan 1, 2000

By M. D. Light

An intelligent control system (ICS) is being developed for ferrous iron oxidation by Thiobacillus ferroxitdans. The ICS provides computerized data acquisition and' control of process variables (temperature, Eh, pH, dissolved oxygen arid carbon dioxide concentrations and dilution rate) to maintain the ferrous iron oxidation at the highest possible rate. The ICS uses fuzzy logic for analysis of data inputs and implementation of control strategies. T:his paper provides preliminary information on the development of the ICS and? its operation.

Jan 1, 1991

By David S. Dolan

To beat capital costs of US$10 per pound of installed capacity has appeared as a major hurdle for the "third generation laterite nickel plants. Forecast costs are escalating. Where can savings come from? Ore beneficiation can reduce the tonnage rate to be processed. High pressure acid leach options include the use of indirect slurry heating and higher operating temperatures to reduce flow rates and residence time. Progress has been reported in atmospheric leaching. High counter current decantation circuit settling rates and high underflow densities reduce CCD costs. Metal recovery options include direct from leach solution to metal production, as used by Bulong and espoused by Goro, and indirect recovery as used by Moa Bay, Murrin Murrin and Cawse. Plant location impacts on the costs of tailings disposal, power and energy costs, supply of consumables and labour costs, among others. Final nickel and cobalt metal production routes are electrowinning, hydrogen reduction or some innovative routes being proposed for Goro. This paper reviews the status in these developments, with particular reference to equipment and processes that offer lower capital costs. Keywords: Laterite, Nickel, Plant, Capital Cost

Jan 1, 2004

By Husamuddin Ahmadzai

A survey of regulations and state of the art control technologies is presented relating to the smelting of primary aluminium, copper and recycling of residues. Some costs associated with the alternatives and trends for the coming decade in this. sector are identified.

Jan 1, 1992

By T. Inami

The chlorine leach of the anode slime was studied in order to improve the treatment process at the Niihama Nickel Refinery. The anode slime originates from the nickel matte electrorefining and, contains 3-5% of nickel as sulfides. A comparative study has been conducted on the filter cake resulting from the sulfur filtration of the molten anode slime. The kinetic factors of the chlorine leach such as temperature, grain size were defined. Under the optimized condition, 70-80% of the nickel is recovered from the slime or filter cake. On the basis of these results, the chlorine leach process for the treatment of anode slime has been established. The leaching plant has been installed and successfully operated since 1986.

Jan 1, 1988

By Ho-Sang Sohn

Copper concentrate particles of 200 to 300 mesh size were fed from the top of vertical reaction tube of 2.8 cm ID and 2 m long with an O2-N2 gas mixture. The reaction tube was heated to 900 K to 1100 K. The residence time of the particles in the reaction tube was about 1 second. The copper concentrate particles were very rapidly oxidized and melted down during their descent in the reaction tube. The particle temperature were calculated by combining an un-reacted core model, mass transfer between gas and particles, and heat transfer between gas, particles and tube wall. The particle temperature reached its maximum within a distance of 60 cm from the top of reaction tube, and it attained at 2000 K at higher oxygen partial pressure. The most particles were melted at the oxygen partial pressure above 20 kPa. An appreciable amount of As, Sb and Pb in the concentrate particles was eliminated in the upper portion of the reaction tube and the rate of elimination are explained by the rate of mass transfer of volatilized species through the gas film on the particle surface and the variation of particle temperature during the descent.

Jan 1, 2006

By In-Ho Chi

In copper metallization, resistivity of copper seed layer is very important since the thickness of seed layer is less than 200iun. Conventionally MOCVD has been used for this purpose however electroless copper plating is simple process and the resistivity of copper deposit is less than that of copper prepared by MOCVD. In this study eIectroless depositions of copper were conducted on different substrate to find optimum conditions of electroless copper plating for electronic applications. To find optimum conditions, the effects and selectivity of activation method on several substrates were investigated. The effects of copper bath composition on morphology were investigated. The effects of pH and stabilizer on deposition rate was investigated. The resistivity of copper with thickness was also measured.

Jan 1, 2001

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 Tingyao Liu, Lihui Han, Qing Liu, Bao Wang, Teng Yang, Yong Sheng

This paper mainly investigates the mass transfer phenomena of rare-earth concentrate from leaching process in Rushton stirred tank reactor with rotate speed of 100-600 rpm. In the research, a certain amount of sphere particles with 50-450 μm in diameter is treated as the mineral particles. Comparison of laboratory experiment data with numerical simulation is performed. The results show that the critical impeller speed for complete dispersion is 300 rpm. And the maximum value of turbulence kinetic energy appeared 15 mm away from paddle, where the mixing time is decreased 55% and 80%, respectively, when mineral particles are injected into stirred tank through one or four filling ports. Moreover, with mixing process going on, the numbers of particles near the paddle region accounts for as much as 58% of the total amount. Meanwhile, following the particle diameter increasing, the particle concentration of the upper part of stirred tank reactor is increased.

Jan 1, 2015

By Stephen M. Testa

Several methodologies are available for the remediation of contaminated soils including bioremediation, vapor extraction, chemical fixation, incineration and direct disposal. A proven innovative and cost effective alternative for the fixation of contaminated soils is via cold-mix Environmentally Processed Asphaltm (EPA"'). EPAm methodology utilizes contaminated soil as an ingredient in an industrial process to produce a commercially viable product. Petroleum hydrocarbon and metal affected soil is incorporated with a water-based asphalt emulsion and varying amounts of aggregate to produce a range of cold-mix asphaltic products that fulfills the requirements of a variety of end uses. This viable and creative use which is within the intent and spirit of current regulations in producing, in lieu of a landfill waste, an end product for use as a berm, road base, liner, or other site specific application. Consideration of certain engineering and environmental factors including durability, stability, chemical resistance and ageing, biological resistance, permeability, leachability and geochemical aspects suggests that cold-mix asphalt incorporation of affected soil will perform more than adequately under normal conditions for a long period of time.

Jan 1, 1994

By William C. Spindler

Five industrial installations of large lead-acid battery energy storage systems in operation in the United States, West Germany and the 'Republic of South Africa will be described. One example is for a deep mine shaft in which air ventilation and personnel evacuation require the highest reliability for emergency power. The battery system is designed for additional cost-effective benefits of peak load lopping and reactive power control. Commercially available lead-acid batteries of the following types are in use1 traction, truck, submarine, high power, and gel. Electrode grids of both the calcium and antimony alloy types are used. Applications include deep and shallow cycling as well as float and intermittent use. The advantages of sealed lead-acid batteries in UPS (uninterruptible power source) systems are well established throughout the world, and such system suppliers could readily develop markets for industrial emergency and peak power lead-acid storage battery installations.

Jan 1, 1990

By N. A. Warner

To filly secure the environmental and social acceptability benefits of making a sulphide smelting facility and its ancillary sulphuric acid plant or other means for fixing sulphur, a virtually zero gas emission operation, it will be necessary to utilise exclusively technically pure oxygen. The strategy proposed for preventing the smelter from overheating involves highly efficient energy transfer by promoting sulphur trioxide formation at a relatively higher temperature than normal. A closed-loop gas circuit uses an eductor system actuated by the process oxygen to recirculate sulphur trioxide and unconverted sulphur dioxide back to the smelter, the endothermic dissociation of sulphur trioxide becoming a major contributor to the removal of excess heat. The only gases leaving the system relate to the bleed of nitrogen impurity introduced in the tonnage oxygen.

Jan 1, 1998

By Manfred K. Walther

"Tests were conducted on instrumented plates cast in the Abex Experimental Foundry to compare recorded solidification histories with results computed for corresponding models simulated with the C.A.S.T. program. The first plate was cast of low alloy steel and the second of carbon steel with a graphite chill at one end. Both were cast in molds of bonded silica sand. Temperature histories were recorded in the castings, molds and chill. Exceptionally good agreement was achieved between computed and experimental data. Other investigators will find the results useful as a benchmark against which they can compare the results of their own calculations.IntroductionSince the early 1970's our foundry engineers have used both two- and three-dimensional versions of the G.A.S.T. program to gain knowledge of the solidification process [1,2,3]. Study of the computed data gave insight as to how the rigging and risering of specific castings might be changed or adjusted to improve quality and yield. New schemes based on such analyses were then recommended for implementation on the foundry floor. The degree of success of the new practice was subsequently evaluated after the part had been poured, shaken out and examined. Similar conditions were noted in the sectioned castings whenever porosity and voids had been predicted by the computations. Appropriate modifications, when found successful in the model, were applied to the process. This led to a reduction, if not complete elimination, of the defects. Such results gave credence to the use of these programs as an aid in the production of better castings.Earlier investigations on simple shapes revealed excellent correlation between output derived with the G.A.S.T. program and exact solutions. Results also compared favorably with data calculated using other codes as reported in the literature [4] and summarized in the Appendix. However, since the computer program had not been verified by direct experiment, it was decided to run instrumented tests to check the theoretical predictions with actual measurements."

Jan 1, 1986

By WenCai Li, Yong Ren, Shuai Niu, Xin Hong

"Temperature measurement is very important in metal smelting process. Many devices are used to realize non-contact temperature measurements. Compared to conventional thermocouple, infrared temperature measurement has it's unique advantages. However, using an infrared temperature measurement at the top of the furnace can not obtain the desired optical signal because of disturbance from slag layer, high-temperature gases and other effects. A real time thermometry system with dual-wavelength radiation was presented to get optical signal emitted from molten metal through bottom-blowing nozzle. Taking into account the advantages and disadvantages of bottom-blowing devices, a MHP (Multiple Hole Plug) bottom-blowing device was used, through which the optical signal was transferred to the infrared thermometer by use of optical fiber. After conversion and analysis in real-time, the result was displayed and recorded in computer. After calibration, it could be a good predictor of temperature trend in a metallurgical process. IntroductionAt the refining stage of steelmaking, in order to achieve predetermined chemical composition and temperature, high-temperature molten steel is refined in a furnace such as converter. Because the refining process involved with chemical components and reaction velocities in the furnace rely on the temperature of steel, it is necessary to know the temperature accurately in real time during the process. And temperature measurement is also helpful for the end-point judgment. The temperature in the refining process changes quickly, for instance, in a converter, 300t molten steel is processed in only about half an hour.At present, traditional way of temperature measurement is using a thermocouple probe mounted on a lifter called a sub-lance. The thermocouple is immersed in molten steel and its temperature is measured during the short period until the thermocouple is fused. Accurate and reliable temperature can be obtained by this method, but in consideration of the discontinuous measurement and the costs, missing the end-point temperature may sometimes occur.According to the above background, a method in which a temperature-sensing element such as a thermocouple is immersed directly in molten steel is not suitable for the continuous temperature measurement because materials having such stability are not available. Therefore, radiation thermometry is promising. There have been some reports on radiation thermometry through an observation nozzle through the bottom or side of a refining furnace [1, 2]."

Jan 1, 2014

By G. S. Hanumanth

Sedimentation of particles during the liquid metal processing of particulate metal-matrix composites can affect the homogeneity, and thereby the properties, of the cast product. A novel electrical probe has been developed to measure the in-situ volume fraction of ceramic particles in molten metal baths. Using this probe, sedimentation rates for 90 pm silicon carbide particles dispersed in molten aluminum A356 alloy were measured over a wide range of particle volume fraction, 0.05 to 0.3. The sedimentation rate was found to depend strongly on particle volume fraction; the time to clarify a 0.15 m depth increased from approximately 60 to 500 seconds as the volume fraction increased from 0.05 to 0.3. Measured sedimentation rates agree well with the predictions of a sedimentation model based on one-dimensional, two-phase flow theory in which the inter-phase drag function is derived from the momentum equation, utilizing the Richardson-Zaki Equation for sedimentation in aqueous systems. The implications for solidification are discussed.

Jan 1, 1993