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By Frank R. A. Jorgensen

Flash smelting is used to smelt a large proportion of the world's copper and nickel and some lead/zinc concentrates. Understanding the factors controlling the ignition of these concentrates is an important consideration in designing burners and maximising the throughput of the flash smelting process. The literature on the subject is briefly reviewed and techniques for the measurement of ignition temperature discussed. The mineralogy of the concentrates and the role of thermodynamics and phase diagrams in interpreting and predicting ignition behaviour are emphasised and applied to interpreting results obtained on a nickel concentrate.

Jan 1, 2002

By M. H. Ghandehari

Sintered (Pr,Sm)Co5 displays a multi-phase microstructure in which closely related intermetallic compounds are formed during the process of fabricating useful magnets from over-stoichiornetric compositions. These compounds have much lower magnetic crystalline anisotropies compared to those of SmCo5 and PrCo5. Despite a careful control of the microstructure in producing "single phase" PrCo5 base magnets, sufficient concentrations of the lower anisotropy phases are formed which act as nucleation centers for domain reversal, resulting in a drop in coercivity. This article describes the use of sintering additives, primarily oxides, to prevent the formation of the magnetically soft phases in the final microstructure.

Jan 1, 1989

By Bernard Bonnetot

The potentialities of hydrogen storage using borohydrides are presented and discussed especially in regard to the recoverable hydrogen amount and to the recovery conditions. A rapid analysis of storage possibilities is proposed taking in account the two main ways for hydrogen evolution: the dehydrogenation obtained using thermal decomposition of borohydrides or the hydrolysis of solid or dissolved borohydrides. The recoverable hydrogen is related to the dehydrogenation conditions and the real hydrogen useful percentage is determined for each case of use. The high temperatures required for dehydrogenation, even using catalyzed borohydrides, lead to poor outlooks for this storage technique. The hydrolysis conditions fix the yield of the recovered hydrogen and rule the storage capacity of the dissolved borohydride, the "fuel".

Jan 1, 2006

By C. Camurri

Results from the Metallurgical Department of Universidad de Conception showed that fire-refined copper could be rolled without previous remelting for deoxidation. The goal of this work is to determine the rheology of fire-refined copper from tensile tests at different temperatures and strain rates, and Ford plane compression tests. All that in order to simulate and calculate rolling process variables. For rheology hardness coefficients, n variables between 0.28 at 600°C and 0.46 at ambient temperature are obtained. The sensibility coefficient for strain rate m varies between 0.056 at 600°C and 0.006 at ambient temperature. The activation energy for plastic flow Q in the considered temperature range is 1436 cal/mol.

Jan 1, 1999

By A. A. Shook

For relatively little capital outlay, the metal delivery control system in the BHP Copper Rod Plant at San Manuel' was significantly upgraded using the UNAC process simulation and control system (CICS Automation, Newcastle, Australia). An accurate simulation of the metal delivery process was developed with UNAC, which was then used to design a robust controller capable of dealing with plant complexities such as noise, time delays, and nonlinearities. This controller was implemented online using UNAC. Thanks to the extensive preparatory simulation, the controller worked immediately and required no additional online "tuning". Operator response has been favorable, and the UNAC control system has become part of the standard operation of the plant.

Jan 1, 1999

By M. W. Wadsley

Despite the convenient subdivision of extractive metallurgy into hydro- and pyro- divisions, many flowsheets contain both types of process. When complex materials are used as feed, combinations of hydro- and pyro-metallurgical processes are even more common. Hydrometallurgy is used to treat many by-products and waste-products. (Bio-metallurgical processes may be considered to be a sub-set of hydro-metallurgical processes.) Combinations of the different processes in the Australian metallurgical industry are described. Selected international examples demonstrate that the use of combked processes is not a unique. Antipodean phenomenon. The motives for selection of combined pyre- and hydro-metallurgical processes in a flowsheet are examined.

Jan 1, 1994

By Henry Freiser

For the last several years, a systematic investigation of the equilibrium extraction behavior of selective tervalent lanthanides with representative chelating extractions of a variety of chelating agent families has been undertaken for the purpose of learning how to obtain chelating extractants of improved selectivity for separating individual lanthanide ions. The equilibrium extraction data (expressed as log Kex) for each reagent system are linearly related to the reciprocal ionic radius of the tervalent lanthanide ions. The role of adduct formation, steric hindrance, as well as the nature of the bonding atom in the chelate ring, represent some of the factors affecting selectivity arising out of our database of over 200 individual extraction systems, which will be discussed.

Jan 1, 1989

By Y. Mori, K. Kawanaka

The permeability changes during the sintering of the feed for the Imperial Smelting Process (ISP) were investigated using an experimental sintering pot, as well as with a mathematical model. The results obtained were as follows. The blowing resistance in the sintering bed changes as the sintering reaction proceeds. It increases at the beginning of the reaction when the temperature of the bed is still low. Then it decreases as the reaction continues, accompanied by an increase of the bed temperature. The increase of the blowing resistance in the bed during the sintering process mainly occurred in the drying zone, and was comparatively small in the reaction and cooling zones. Based on Erugen's equation, the change of the permeability during sintering is explained by the decrease of the apparent fractional void volume in the drying zone of the bed.

Jan 1, 2000

By Jun-ichiro Yagi

A mathematical model has been developed for simulating the blast furnace operation with carbon composite agglomerates charging based on multi-fluid theory and reaction kinetics. In this model, the behaviours of carbon composite agglomerates are considered on the basis of previously reported conservation equations and experimental research on the reduction rate of carbon composite agglomerates. A series of calculations are performed to examine the effect of charging carbon composite agglomerates. The model calculation gives two-dimensional distributions of process variables and information on the overall operational parameters. It reveals that in-furnace temperature levels significantly decrease and the reduction of carbon composite agglomerates is retarded with carbon composite agglomerates charging ratio. The furnace performance is remarkably improved with the increase in carbon composite agglomerates rate. The productivity tends to increase while coke rate and total reducing agent rate show decreases at the different degree.

Jan 1, 2006

By C. K. Gupta

Electrometallurgical processes have a definite place in the extraction technology of rare earth metals and alloys. Some of the advantages of the molten-salt electrometallurgical processes include fast electrode reaction, providing accurately controlled large amount of energy to a relatively small reactor volume, negligible over voltage, simplicity of operation, and possibility of accomplishing continuous or semicontinuoue operations. This paper provides a vivid account of the theoretical and practical aspects of electrometallurgical processes for the production and processing of some of the rare earth metals and alloys. Reference has been drawn to the work reported on electrometallurgical processes as applied to the preparation of lanthanum, cerium and misch metal from author's laboratory.

Jan 1, 1992

By P. J. Moor

Britannia Refined Metals Ltd. was built in 1931 to refine the lead bullion produced at the Mt. Isa mine in Queensland, Australia. Several periods of expansion and development have taken place over the intervening years, leading to major increases in the refining capacity for both lead and silver. A plant for treating recycled lead-acid batteries was added in 1976. This was redeveloped in the early 1990's to utilise Isasmelt technology for the smelting operations. Most recently the No. 2 refinery kettle floor was extended to enable it to process lead bullion produced from two Imperial Smelting Furnaces (ISF), at Britannia Zinc Ltd. in Avonmouth, England and at MIM Hüttenwerke in Duisburg, Germany. This expansion included the provision of a plant for the hygienic handling of drosses and skims. This paper briefly describes the present primary refining operations and gives an update on the most recent developments in the process metallurgy and operating practices that have taken place.

Jan 1, 2000

By C. R. Bennett

The first phase in the design, development and implementation of a comprehensive computational model of a copper stockpile leach process is presented. The model accounts for transport phenomena through the stockpile, reaction kinetics for the important mineral species, oxygen and bacterial effects on the leach reactions, plus heat, energy and acid balances for the overall leach process. The paper describes the formulation of the leach process model and its implementation in PHYSICA+, a computational fluid dynamic (CFD) software environment. The model draws on a number of phenomena to represent the competing physical and chemical features active in the process model. The phenomena are essentially represented by a three-phase (solid-liquid-gas) multi-component transport system; novel algorithms and procedures are required to solve the model equations, including a methodology for dealing with multiple chemical species with different reaction rates in ore represented by multiple particle size fractions. Some initial validation results and application simulations are shown to illustrate the potential of the model.

Jan 1, 2003

By K. Th. Mavrommatis

Cleanness of steel is justified, measured and estimated in steelmaking process through different concepts which are mainly based on operational, empirical or semiempirical parameters and describe ?cleanness as a state?. In this work a theoretical concept is developed, considering ?cleanness as a process? and introducing a dynamic aspect into the quantification of cleanness of a steel melt, linking operational parameters with physicochemical variables, which are based on first principles. This concept and the here derived and developed variables and parameters are based on the earlier defined agglomeration index (AI) of a steel melt, the ratio of the mean inclusions diameter (MID) to the mean inter-particle distance (MIPD), which is shown to be a measure of the agglomeration tendency of the melt after deoxidation, and can serve both, to monitoring cleanness during steelmaking operation and to be useful as a basis for mathematical modelling of cleanness and of the metallurgical measures in plant, associated with production of clean steels.

Jan 1, 2006

By Karel Verscheure

Reliable furnace cooling technology is a domain of increasing concern to the pyrometallurgical industry as it can significantly increase process intensities, productivity and campaign times of furnaces. Although there are many advantages in using cooling systems, they also impose a variety of problems mainly related to safety, heat losses and sustainability of the operations. The choice of cooling system is hence a matter of trade-offs and differs for every metallurgical application. This paper gives a review of different cooling designs used in the ferrous, non-ferrous and alloying industries. Additionally, the paper systematically reviews aspects of materials selection, manufacturing, installation, water quality and furnace monitoring when using water cooled refractories.

Jan 1, 2006

By Ennio Bonetti

The technological applications of MgH2 hydrides for hydrogen storage demand the overcoming of some critical issues: an improvement of the reaction kinetics and a reduction of the desorption temperature. The synthesis of nanocrystalline MgH2 by reactive milling and inert gas condensation and a proper metal catalyst addition, constitute recently employed strategies. In the investigation of the hydrogen short and long-range dynamics, sorption kinetics and nanostructure stability, the mechanical spectroscopy offers some specific advantages. In the present research this technique was employed with other experimental approaches (XRD DSC) to investigate relaxational and structural damping processes in nanocrystalline MgH2 with added catalysts (Fe). Time/temperature variation of the dynamic elasticity moduli and mechanical quality factor are correlated to hydrogen anelastic relaxation processes and concomitant structural transformation of MgH2 to Mg associated to long range H diffusion. Results are discussed with reference to microstructural modification strategies able to assist hydrogen release.

Jan 1, 2006

By Hector M. Henao

There is an increasing trend in the copper smelters to recycle electronic materials, which contain relatively high concentration of precious metals. As a consequence, the amount of precious metals lost in the slag phase is increasing. To determine the portion of the precious metals chemically dissolved and that associated with the mechanically trapped matte in the slag will be a key factor to improve the recovery of those metals. Thus, an experimental study was carried out to determine the distribution of precious metals (Au, Pt, Pd, Rh, Ru) between the equilibrated copper matte and iron-silicate slag phases. The experiments were made in a magnesia crucible at 1573 K and a fixed partial pressure of SO2 of 0.1 atm for the matte grades between 40 and 70 mass% of copper. It was found that the distribution ratios (defined as mass% X in slag/mass% X in matte, where X represents the precious metal) are around 10-2 for Ru, 10-3 for Au, Pt and Pd and 10-4 for Rh. The distribution ratios show a tendency to increase when the grade of matte is increased.

Jan 1, 2006

By N. Lohja

Metallurgical industries are generally big producers of solid residues of various kinds. In contrast with the past where environmental sensibilities were not so elevated and the accumulated mass of these residues were not considerable, these days the solid residues are everywhere scrutinized among others in term of their harmful environmental impact and as possible materials for valuable elements extraction or secondary utilisation. As a case study, the present paper gives an overview of the solid residues discharged by the metallurgical industry in Albania for the last tens of years. The results of two monitoring study on the solid residues of copper, iron and ferrochromium producing industries are also summarized. The first deals with the origin, quantities and chemical composition of these residues and the second one with the impact of harmful ingredients of these residues in the environment. Some methods for the processing of these solid residues are also proposed in order to ensure a clean environment and to make not just possible but also economically viable their secondary utilisation. This work is part of a bigger cooperation project among local institutions and foreign expert companies such as Flogen Technologies Inc and other in various countries that will not only monitor the situation but will also develop appropriate technologies for treatment of these specific residues.

Jan 1, 2006

By Bruce W. Downing

MagPower has developed methods to control the detrimental formation of hydrogen that occurs in electrochemical reactions in numerous commercial applications such as the Magnesium-Air Fuel Cell, electrowinning, zinc alkaline batteries, hydrogen embrittlement, waste water/ metal recycling and coolants. The company?s approach to an alternative energy source is the development of an environmentally friendly non-toxic alternative power source that generates electricity through a combination of magnesium, oxygen and a saltwater electrolyte with MagPower?s patent pending hydrogen inhibitors. The magnesium-air technology has never reached the commercial stage due to its limiting power output caused by hydrogen generation. MagPowerhas solved this problem and has patents pending on its intellectual property; the Hydrogen Inhibitors and has developed several consumer power units for a variety of applications through licensing agreements. The company has also shown that the inhibitors have an impact on zinc electrowinning through laboratory test work where current efficiency was improved. This will significantly reduce power consumption and increase the efficiency of the electrowinning process, as well as reduce the potential acid mist hazards associated with electrowinning.

Jan 1, 2003

By Steven Wright

BHP Billiton?s Olympic Dam copper flash smelter employs the direct to blister process for smelting high grade copper concentrates. SO2 evolution during tapping gives rise to safety concerns. A thermodynamic model for the blister copper (Cu-Fe-S-O) was used to predict the volumes of SO2 evolved. The Multiple Phase Equilibria Model (MPE) was used to evaluate the slag chemistry inside the furnace. The blister copper model was used to explore the relationship between %S and %O in the copper and the amount of SO2 evolved on cooling. The volume of SO2 evolved was sensitive to the O content with reduction to levels below 0.2 ? 0.15% likely to suppress SO2evolution on cooling. Concentrations of S and O in copper samples from trials generally lay above the equilibrium line calculated for an average temperature of 1275C and a partial pressure of SO2 of 1 atm. Consequently there is a thermodynamic driving force for SO2evolution when cooling to this temperature during tapping. A number of potential process options to suppress SO2 evolution on tapping were investigated thermodynamically. Some of the options require treatment of the blister in a forehearth or separate furnace, while others impact on current practises in the flash furnace with slag present. The opportunities that these options present are discussed.

Jan 1, 2006

By Lanre Oshinowo

The trend in process engineering is to design compact, more efficient processes, there is the paramount requirement to get the job done right the first time going from the drawing board to full-scale commercial operation. To accomplish this goal, there is also the need for tools beyond the traditional engineering toolkit to evaluate designs through virtual prototyping, thereby reducing the risks associated with making design decisions. One of the most important tools that has recently come to the forefront of process design and development is Computational Fluid Dynamics (CFD). CFD has been used at HATCH to address the key process parameters that drive the design of hydrometallurgical unit operations. This paper will detail the role of CFD at HATCH in achieving a superior level of confidence in the process design of autoclave circuits. Specifically, the optimum application of multiphase modeling including hydrodynamic, heat and mass transfer to hydrometallurgy operations, the impact of non-Newtonian slurry rheology on autoclave performance, and the challenges of optimizing the mixing of key reactants into slurries in autoclave reactors, is discussed.

Jan 1, 2003