Search Documents

By B. W. Lightfoot, Neill F. Arthur

"The AusIron process is a new development of the well established Ausmelt bath smelting technology(l). The development of this technology has been tied to the South Australian Steel and Energy (SASE) project which brings dedicated coal and iron resources together with this new technology. SASE is a joint venture between Ausmelt (40%), Meekathara Minerals (40%) and the South Australian Government through Mines and Energy South Australia (MESA) (20%). It will use a multiple lance furnace to process iron ore using steaming coal for both fuel and reductant.It is intended to build the simplest plant economically possible. Refinements such as preheating and prereduction of the ore are compatible with the technology but are not expected to be necessary in the first generation plant.The joint venture is negotiating with suitable partners for funding of the project through to commercial implementation at a target scale of2.5 mt/a of pig iron.ObjectivesAusIron aims to produce pig iron directly from steaming coal and from any of a variety of iron sources in a simple furnace system with a minimum of pre-processing of either coal or iron ore. Preheating and prereduction of ore are compatible with the technology but may not be necessary. The immediate aim is not to be the technology that uses the least quantity of coal to produce iron metal but rather the technology that uses the least number of dollars to produce metal.The chemistry of iron making is well known, probably better known than that of smelting of any other metal. Iron has been made for thousands of years and it is possible to make iron from charcoal and ore in a simple blast furnace the size of a beer barrel. The focus is therefore not making iron but rather making it more cheaply than it is made by current technologies. Large blast furnaces now set the standard and new technologies must perform better if they are to gain market share. It is still the cost of iron, energy units and capital going into these mega blast furnaces which ultimately set the market price for pig iron."

Jan 1, 1996

By Melvin A. Jennings

Ion-exchange technology for precious metals recovery is at a turning point. Some very exciting technology has been developed in the past five years which should lead to commercialization of the process. Ion-exchange will allow not only for the recovery of gold and silver, but also will allow for the recovery of cyanide form plant tailings. This process may soon be competitive with Merrill-Crowe for silver and once this occurs, it will become the process of choice.

Jan 1, 1991

By Rudolf Keller

In the electrolysis of neodymium oxide from a molten fluoride electrolyte, anode effects may occur at the carbon anodes, interfering with smooth cell operation. In laboratory experiments, we attempted to circumvent this problem by selecting electrolytes with a high oxide concentration, possibly at relatively low rare earth content, but cathodic deposition was not satisfactory. A regime at higher cell voltage was discovered to yield good cell performance, but evolution of considerable amounts of fluorocarbon compounds suggested that a reactive treatment of the off-gases would be necessary for environmental acceptability. Subsequent experimentation at low cell voltage revealed conditions for satisfactory operation without occurrence of anode effects and without formation of any CF4 or C2F8.

Jan 1, 1997

By Tullio Corsini

Scrap battery recovery process, developed by Engitec Impianti S.p.A., is improved transforming batches operations in continuous. Benefits expected: constant and better quality of the products; easier and more reliable control of the operating parameters, reduction of manpower requirements. Paste will content less sulfate, particularly in soluble form. Sodium sulphate is obtained with higher and constant purity.

Jan 1, 1993

By J. Partinen

Drying is a unit process which has numerous applications in metallurgical process industry. Kumera Technology Center, being a worldwide equipment and process supplier, has developed sophisticated solutions for both direct and indirect drying. In conventional direct drum drying, the energy is taken from combustion of fossil fuels, requiring energy input and emitting considerable amount of off gases. In modem copper smelters, thermal energy from the off gases is recovered in waste heat boilers making the steam available. Using that steam as the energy source for concentrate drying, the total volume of off gases can be considerably reduced and releasing of harmful combustion gases into the atmosphere can be avoided. Kumera Technology Center has recently developed and promotes a new steam drying process for drying of copper concentrates. In the development of the new dryer, Kumera's approach has been to combine the best properties of both the steam dryers and the drum dryers. In the design special attention has been paid to overcome problems of excessive wear and clogging and to reduce the required maintenance operations. In this paper the environmental issues and energy consumption related to both direct and indirect drying processes are discussed. The estimated operation costs and emission levels are compared, based on calculations and the data collected from industry. Finally, the development project of the Kumera Steam Dryer is briefly reviewed

Jan 1, 1999

By F. Michael Hosking

Modeling of a furnace brazing process is described. The computational tools predict the thermal response of loaded hardware in a hydrogen brazing furnace to programmed furnace profiles. Experiments were conducted to validate the model and resolve computational uncertainties. The results from selected furnace simulations and measured thermal events were compared. Critical boundary conditions that affect materials and processing response to the furnace environment were determined. "Global" and local issues (i.e., at the furnace/hardware and joint levels, respectively) are discussed. The ability to accurately simulate and control furnace conditions is examined.

Jan 1, 1998

By S. B. Breyner, A. Ressler, D. Gregurek, A. Spanring

"The changes in process conditions that frequently decrease the service life of refractory products provided incentive for RHI AG to develop high performance bricks, especially for non-ferrous metal applications. Innovative product development was required to determine suitable refractory products for improving lining life. At the Technology Center in Leoben, Austria, practical corrosion testing methods and facilities, including an induction furnace and rotary kiln, enable detailed comparative analysis of brick wear on a pilot scale. In tests that were carried out using a fayalite type slag, the newly developed RADEX VFG magnesia-chromite grade showed very promising results compared to the standard grades. Based on the test results, optimal refractory solutions can be recommended for this challenging industrial application and field trials can be performed directly at the customer's site.IntroductionThe complexity of metallurgical processes in the non-ferrous metal industry, and especially changes to the process conditions in combination with the diversity of metal processing furnaces ''', requires a precise understanding of each individual system for appropriate refractory product selection l2'. In addition, particular importance is focused on the specific refractory consumption being as low as possible.Another important aspect results from the global shortage of resources, which forces companies to invest in recycling processes. In the base metal industry, recycling operations have resulted in significant changes; for example, operating with two slag chemistries and process temperatures will influence the performance of previously suitable linings. The raw material mix for primary smelters has also changed, including higher levels of secondary raw materials in the smelter feed."

Jan 1, 2012

By Fumito Tanaka

The Converting Furnace (C-furnace) of the Mitsubishi process has solely provided opportunities for producing blister copper continuously from molten matte. Continuous converting originates from the proven technology for controlling the behavior of magnetite in lime-ferrite slag of the CaO-FeOX-Cu2O system. Recent improvements in the C-furnace operation have included the slag controls reflecting the impact of minor oxides on magnetite behavior. Although previous investigations focused on magnetite behavior, sulfur has also affected the C-furnace operation because it is of practical importance to avoid the precipitation of gypsum from lime-ferrite slag and the separation of matte from blister copper. This paper will quantify the behavior of sulfur in C-furnace with respect to the gypsum formation and matte separation, and discuss better controls for C-furnace operation.

Jan 1, 2006

By Pedro Lobarinhas

In the present work a two dimensional computational model is derived for the description of the time dependent heap leaching process. The flow inside the heap is calculated using the diffusion equations for the flow in porous media. The soil conductivity is also estimated assuming a close packed structure for the grain packing inside the heap. These equations, with appropriate boundary conditions, are solved using a time step splitting scheme. From this calculation the amount of leaching reagent in contact with the ore at any position inside the heap can be calculated and, once coupled with appropriate reaction equations, the amount of metals extracted can be computed and leaching agent concentration updated. The model is tested with available experimental data and the results have shown to be in a very good agreement. The model predicts all the transient features of the data.

Jan 1, 1999

By Timothy W. Skszek, Adrian S. Sabau, Hebi Yin, Xiaoping Niu

The microstructure evolution during solution treatment plays an important role in mechanical properties of heat-treated aluminum alloys. In this paper, models were reviewed that can predict the microstructure evolution during the solutionizing process of the aging heat treatment of aluminum alloys. The dissolution ofMg2Si particles has been modeled as a diffusion process of Mg in the a-Al matrix. The evolution of volumetric fraction of fragmented silicon as a function of time and temperature was also considered. The growth and coarsening of silicon particles during the heat treatment was considered. It was found that constitutive equations and required property data for most of the phenomena that need to be considered are available. Several model parameters that need to be obtained from material characterization were identified. Pending the availability of these model parameters, this comprehensive model can be used to describe the microstructure evolution of aluminum alloys in order to optimize the solutionizing heat treatment for energy savings.

Jan 1, 2013

By P. A. Davidson, D. J. Short

"In this paper we describe a 'non-contact' electromagnetic nozzle suitable for sprayforming and gas atomization processes. In such processes there is a need to control the flow rate and diameter of the liquid metal jet whilst minimising contamination of the stream. This can be achieved using an electromagnetic valve, which partially levitates the jet in freespace, using a segmented cylinder surrounded by an induction coil. This valve will significantly enhance the quality of the titanium alloys and nickel-based superalloys used in sprayforming and gas atomization. This paper describes the design and test of a laboratory prototype valve based on experiments performed with liquid tin.1. Introduction In many industries there is an increasing need for clean, high quality metals and alloys based on titanium and nickel. Two important processes are: 1) Spray deposition which allows the liquid metal to be converted to a near-net shape, thus alleviating the need for subsequent forging and extensive machining and; 2) Powder production of titanium by gas atomisation.In centrifugal spray deposition of titanium (see figure 1) the metal is induction melted in a cold crucible. The crucible consists of a number of water-cooled segments, which allows the high frequency magnetic field of the coil to pass through the crucible, and into the melt. The charge is melted by the induced eddy currents. Locally at the crucible walls the liquid metal solidifies, and is contained within a. 'skull' of its own solid, thus reducing contamination from the crucible wall. Once melted the metal is poured through an electrically heated graphite nozzle and into the spray forming chamber. The principal limitation of the process to-date, however, is that it currently uses a graphite and /or ceramic nozzle to direct the flow of liquid metal to the atomizing disk and as such there is considerable risk of nozzle erosion with inevitable effects in terms of contamination of the melt stream and variability in flow conditions. In this research programme we develop a. non-contact electromagnetic nozzle, which will totally eliminate refractories and/or ceramic materials from the melting and casting process. This will greatly enhance the technological capabilities of sprayforming and gas atomization processes."

Jan 1, 1999

The increasing need for robust pyrometallurgical furnace construction is driven by two trends in the copper and other base metals smelting industry: ? the desire for increased production within a single furnace line by greatly increasing smelting intensities, which generates high heat fluxes to the crucible. walls, and ? the operational and economic imperatives of maintaining high percentage on- line times and long campaign lives between rebuilds. A key feature of furnaces capable of producing at high rates, while containing intense processes, is a strong, thermally robust wall cooling system. Equally important design aspects include the furnace steel structure, refractories, a cooling water supply and piping arrangment for safety from leaks and disruptions, and instrumentation/controls for monitoring and rapid mitigation of process excursions. Integration of the cooling elements into these furnace systems is essential for optimum performance of the cooling elements, and indeed the entire furnace. This paper discusses the development of a composite copper / refractory water- cooled design, which has been successfully implemented on several copper smelting and converting furnaces, including Kennecott's flash converting furnace, INCO's MK reactor, and Kidd Creek's converting furnace.

Jan 1, 1999

By Kenji Monden

A simple technique is presented to evaluate optical property of biomimetic microlens array (BMA) as an antireflective surface on a polydimethylsiloxane (PDMS) sheet. The integration of these structures is done by a thermoforming process. We have only UV-VIS spectrophotometer for optical evaluation apparatus. The transmittance of the sheet is measured with angled sample holder. The 50 deg. transmittance of 270nm pitch BMA on PDMS sheet increases from 87 to 92% after the moth-eye structure is introduced. The transmittance of 350nm pitch BMA on PDMS sheet increases from 87 to 96% after the moth-eye structure is introduced. The transmittance increases with increasing pitch of BMA. The results obtained using UV-VIS spectrophotometer with handmade sample holder.

Jan 1, 2015

By Peter K. Eriksson

Nanofiltration is very efficient in separating heavy metals from water solutions, even if they contain strong acids. Desalination System, Inc., has many years of experience in this area, and this paper deals with three different such cases. The first case deals with concentrating the heavy metals in the pregnant leach solution from a copper dump leaching site with a surplus water problem. The increased copper concentration in the pregnant leach solution increases the capacity of the following copper extraction stage. The nanofIltration permeate is polished with a biomass adsorption column to remove the small amounts of remaining heavy metals, before being discharged. This method eliminates sludge handling and disposal, which are quite costly with the alternative precipitation process. In the second case, a complicated precipitation method was used to remove heavy metals from the waste stream of a specialty metals manufacturer. Nanofiltration was installed to increase the metals concentration four times, which greatly simplified the precipitation process. The chemical consumption and sludge production decreased by more than 80 percent, and the labor cost decreased by 66 percent. In the third case, nanofiltration was used to purify waste sulfuric acid solutions containing heavy metals, to meet the specifications for technical grade acid. Sulfuric acid concentrations above 30 weight percent were successfully purified in a multiple pass membrane system.

Jan 1, 1996

By K. Takahashi, G. Dodbiba, T. Fujita, N. Sato, S. Matsuo, K. Okaya

Different materials are used for manufacturing various parts of a cellular phone. Considering that a great number of mobile phones are being discarded every year, it is important to recover these materials and then recycle them in order to save resources. The primary objective of this work is therefore to find and suggest ways on how to recover various materials from discarded cellular phones for recycling. Much effort, for example, has been put in recovering and recycling tin oxide (ITO), a mixture of indium (III) oxide, (UI2O3) and tin(IV) oxide from the discarded liquid crystal displays (LCDs). Here we report a simple and cost-effective process, which includes a HC1 treatment process for altering the structure of the indium (III) compound into a chlorideinduced indium compound, in order to facilitate the vaporization of indium at a relatively low temperature. The experimental results indicated that 96.2 % of indium can be recovered from ITO, when the sample was heated at 973 K for 90 minutes. In addition, some thermodynamic calculations were also carried out in order to better understand the mechanism for chlorideinduced vaporization of indium.

Jan 1, 2011

By R. Y. Wan

Thiocyanate was evaluated for gold recovery from low-grade refractory gold ores following biooxidation for an acidic heap leaching approach. One of the important features in using thiocyanate is that the leaching can be performed in acidic media, thus avoiding problems related to neutralization and material handling as leaching with alkaline cyanide. Also, the acidic leaching enables the use of ferric ion or bioleach solution as oxidants. In this study, Newmont-Nevada low-grade refractory sulfidic ore was biooxidized in columns at a particle size of 100% passing 102 mm. Thiocyanate leach on the biooxidized ore sample was performed on both ground samples in pulps and coarse material in columns using ferric ion as an oxidant. The variables of thiocyanate and ferric ion concentrations were compared for effect on leaching. Thiocyanate leach results are encouraging and indicate potential for development of a practical process. Gold extractions by thiocyanate are comparable to cyanide leach. Thiocyanate consumption was higher than cyanide, but was in an acceptable level.

Jan 1, 2003

By Patricio F. Mendez

This paper presents a formalism to automate portions of the traditional scaling procedure. This formalism, called here Order of Magnitude Scaling (OMS), captures essential components of the governing equations into a set of matrices and arrays amenable to computer implementation using standard linear algebra tools. This approach is valid and specially useful for large systems of multicoupled equations. The matrix approach proposed enables one to automate operations such as normalization, dominant balance, obtention of characteristic values, and check for self-consistency. Also, automation permits an exhaustive exploration of all possible balances and the discovery of unsuspected scaling laws. As an example, OMS is applied to the analysis of the viscous boundary layer with no external pressure gradient. The obtained scaling laws for boundary layer thickness and transverse velocity are the same as those obtained with traditional scaling, and in addition, a meaningful estimation for pressure variations within the boundary layer is obtained; this last estimation is typically not addressed in the manual analysis.

Jan 1, 2006

By O. M. G. Newman

Research into potential applications of spouted bed electrowinning (SBE) in the zinc industry was conducted, in a collaboration between our two organizations. The main system investigated was zinc from acidic sulfate electrolytes. However, SBE can be extended to other electrolytes, or recovery of other elements. Electrolytic tests were carried out at the 0.01 to 0.1 m2 scale. Spouting behaviour has been studied at a larger scale, approaching a size suitable for an industrial unit cell. Much of our work was carried out using a micro-porous separator (Daramic®). However, we have also shown that ion exchange properties can have a controlling effect on the process chemistry, electrochemical efficiency, and plant flowsheet. In initial 0.1 m2 scale electrolytic tests, design and engineering issues for scale-up were identified. We review the major achievements, promising areas for application in the zinc industry, current status, and remaining barriers to development of SBE technology.

Jan 1, 2003

By Yang Hai-long, FAN Gang, LI Cun-xiong, WEI Chang, LI Min-ting, LI Xing-bin, DENG Zhi-gan

Hydrothermal sulfidation of pure cerussite with elemental sulfur has been reported in the present paper. The variables considered in the study were temperature, time, particle size and elemental sulfur fraction in the reacting mixture. Temperature was the most important factor at temperatures above 180 , PbS and PbSO4 were the only stable reaction products in the sulfidation of cerussite. The experimental data indicated that under the hydrothermal conditions with a particle size of -74+58 μm and sulfur fraction in reacting mixture of 15% at 200 °C for 120 min, and 92% of lead sulfidation rate was achieved.

Jan 1, 2016

By John R. Hugens

Modifications in the ALSCAN method of measuring hydrogen dissolved in liquid aluminum have made it possible to monitor the level of hydrogen dissolved in liquid copper. Measurements from the tundish show a correlation with eddy current readings from the continuously cast and rolled copper rod from the continuous casting and rolling system at Amarillo. The measurements also indicate that the copper in the tundish is supersaturated with hydrogen.

Jan 1, 1994