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By T. N. Chan

This paper provides some general discussions on the development of a new beneficiation process for the treatment of a highly complex monazite orebody located at Mt Weld, Laverton, Western Australia. The complexity of this rare earth ore and the associated problems encountered in ore preparation, desliming and flotation in beneficiation during the development study stage and the solutions to these problems are reviewed.

Jan 1, 1992

By P. Regan

Following the introduction of the Contilanod process over 10 years ago at Copper Range and IMI Refiners, significant changes and advances have been made to this pioneering anode production technique. A new radial flow metal feeding concept has been developed that allows a substantial increase in casting rates on the Hazelett® twin-belt caster. To cut the 45 mm thick continuous anode plate into shaped anodes at rates of 100 t/h or more, a filly moving hydraulic shear designed by Mannesmann Demag has replaced the slower speed plasma cutting torch. Details of the.new caster and shear are presented along with operating results from the new lines starting up in 1999 at the Gresik smelter/refinery in Indonesia and the completely revitalized Mansfelder Kupfer und Messing complex in Germany.

Jan 1, 1999

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 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

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 Qixing Yang, Björn Haase, Fredrik Engström, Anita Wedholm

"MiMeR, the Minerals and Metals Recycling Research Centre at Luleå University of Technology, Sweden, started industry-related research work to stabilize an EAF slag from Höganäs AB with of CaO/SiO2 values near to 3.2. The intention was to determine the suitability of the EAF slag as construction material after stabilization. Some of the stabilizers effective for preventing disintegration of AOD slag were examined in laboratory tests for stabilization of the EAF slag. The EAF slag samples were mixed together with stabilizers for melting at 1600ºC and then cooling in a crucible system. With a laboratory granulation system, the liquid EAF slag was cooled rapidly using air. Samples from the tests were characterized by different techniques, including XRD and SEM. Some of the results from the work may be useful for preventing slag disintegration and, thus, enhancing utilization of the EAF slag as construction material, thereby saving valuable natural resources.IntroductionAt steel plants of some MiMeR member companies, steel grades with low carbon contents were produced in Electric Arc Furnaces (EAF). EAF slag was tapped out of the furnace to slag pots for transport to slag yards, where the slag was poured on the ground. Very often, the EAF slag disintegrated during cooling on the ground. Fines from the slag disintegration were often difficult to handle and use as material for road construction [1, 2]. The EAF slag disintegration was rather similar to the disintegration occurring in the slag tapped from some AOD (Argon Oxygen Decarburization) converter heats.Literature studies show that formation of dicalcium silicate (C2S) is the main reason for the disintegration or dusting of AOD slag from production of stainless steel [1-4]. The C2S can form while the content ratio of CaO to SiO2 of the slag, CaO/SiO2, exceeds 1.4 [1]. Values of CaO/SiO2 for the AOD slag are often near to 2.0, making the C2S a predominant slag component. The ß phase of C2S, ß-C2S, transforms into its low temperature ? form in the temperature range of 400-500°C, inducing a volume expansion of nearly 12% [1-4]. The volume expansion disintegrates the AOD slag."

Jan 1, 2008

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 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 R. J. Batterham

This paper sets the scene for the Australian-Asian Pacific Course and Conference on Pyrometallurgy for complex materials and wastes. The relentless presence of competitiveness is rehearsed as the source of the current trends towards continuous improvement and benchmarking. While this might be expected to lead to more spending on pyrometallurgy, the opposite appears to be the case. The paper examines the reasons and suggests that we face an increasing challenge for selective developments that can lead to sustainable competitive advantage - both in mineral and in waste processing.

Jan 1, 1994

By James D. Navratil

The mineral magnetite, or synthetically prepared iron ferrite (FeO?Fe2O3), has been used to separate a wide variety of substances, such as dissolved metal species and particulate matter, from wastewater. In the absence of an external magnetic field, activated magnetite readily adsorbs numerous metal species including actinide elements. In the presence of the external magnetic field, enhanced capacity was observed in using supported magnetite for removal of actinides and heavy metals from wastewater. The enhanced capacity is primarily due to magnetic filtration of colloidal and submicron particles along with some complex and ion exchange sorption mechanisms. The removal of the magnetic field and use of a regenerating solution can easily regenerate the loaded magnetite. The process has recently been tested for the removal of other metal ions including cobalt and iron. This paper will review previous work on the use of iron oxides for wastewater treatment and discuss the development and potential of the magnetic filtration/sorption process for wastewater treatment applications in hydrometallurgy.

Jan 1, 2003

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 Chai Liyuan

Chromium-containing slag was detoxified by the method of microbial treatment using Ch-1bacteria isolated from nature by our research group, belonging to achromobacter sp. and with the characteristic of reducing high concentration of Cr(VI) in alkaline solution. The detoxifying process of Ch-1 to chromium-containing slag was studied by column-leaching techniques respectively. The results indicate that Cr(VI) in leachate can not be detected when chromium-containing slag has been column-leached for 7 days, and Cr(OH)3 content in precipitate is up to 32.8% with great value of resource recycling. Flowchart of engineering experimentation was ascertained based on the parameters of column-leaching experiments. Using the technique of pelletization of chromium-containing slag heap-leaching by Ch-1,the leaching rate of water-soluble Cr(VI) existing in chromium-containing slag reaches up to 100%, while the leaching rate of full chromium is up to 90%, when the process has been operated for 7-10 days under the conditions of 25-40C and consecutive spray by circular leachate. The content of Cr(VI) in chromium-containing slag after detoxified meet the national identification standard for extraction procedure inxicity for hazardous wastes(GB5085-1996) in China, moreover approximately 90% of Cr(VI) existing in chromium-containing slag has been recycled.

Jan 1, 2006

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 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 Maura Malone, Neil Gao, Daniel Liu

"Corrosion is the primary failure mode for aluminum cathode sheets used in Teck's Trail Operations electrolytic zinc plant. It was observed that the corrosion performance of Al cathodes from different suppliers varied considerably. This suggests that the material properties of Al cathodes have a strong influence on corrosion resistance. In the current study, various types of Al alloys, including 1050, 1060, 1070, HIS and 1090, were characterized through chemical analysis, corrosion testing, mechanical testing and metallography. The results are discussed with a focus on the effects of impurity elements and second phase particles on corrosion resistance. The findings were used to improve the Al cathode sheet specification and to develop a standardized screening procedure which details qualification steps for comprehensive evaluation prior to a plant trial.IntroductionAluminum (Al) cathode replacement is a major operating expense at Teck's Trail Operations zinc electrolytic plant. Currently, approximately 0.5% of daily stripped Al cathodes are removed from service because of failures caused mainly by corrosion. Edge corrosion and acid (solution) line corrosion are the most severe types of corrosion, resulting in more than 50% of cathode failures.Corrosion of Al cathodes has been intensively investigated for over two decades and the origins and mechanisms of Al cathode corrosion are well understood [1-4]. Halide anions contained in the electrolyte are the primary culprits for the corrosion and sticking problems of Al cathodes. Both fluoride (F') and chloride (Cl"") result in localized passivity breakdown on the surface of the Al cathode, causing pitting corrosion. Bouarzaiga investigated the corrosion of Al cathode samples partially immersed in electrolyte and found that the formation of Ch at the electrolyte/air interface was the primary contributor to solution line corrosion [2]. Because of the significant impact of F"" and Cl"" on Al cathode corrosion, it is imperative to maintain these concentrations as low as possible in the electrolyte."

Jan 1, 2012

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 Brad Wahlquist

An ex-situ biological treatment system was implemented at a gold mine site in South Dakota. The system removes selenium and nitrate from a mixture of groundwater and surface water runoff at ambient water temperatures. The Applied Biosciences? system replaced a denitrification system that did not perform consistently, did not treat for selenium and required heating of the influent water. Installation was completed in phases starting with the selenium circuit being brought into operation in February, 2002 and the nitrate circuit in March, 2002. System design can accommodate average flows of 380 L/min (100 gallons/minute) and a maximum flow of 1,136 L/min (300 gallons/min). Four cells were designed to remove nitrate from approximately 30 mg/L to below 10 mg/L and two cells were designed to remove selenium from 0.01 mg/L and higher, to below 0.005 mg/L. No pretreatment is required to operate the system at ambient temperatures, which can fall as low as -12C in the winter, and treat water at temperatures ranging between 8C to 16C. Nutrient requirements are met using a sugar based nutrient mixture that includes a balanced C:N:P:S ratio, trace elements and vitamins. Since start up, the system has consistently been in compliance for nitrate and selenium, treating water to below detection limits for both contaminants. This paper discusses laboratory biotreatability testing of a system designed to remove selenium, arsenic, and nitrate and full-scale implementation and optimization of a system to remove nitrate and selenium.

Jan 1, 2003

By Lan Li, Izaak Williamson

"The efficient separation and storage of CO2 from power plant flue gases can reduce the amount of CO2 released into the atmosphere and mitigate global warming. Potential candidates for industrial applications are solid sorbent materials. Crucial factors to control the efficiency of porous sorbent materials include the framework and pore structure, and the chemical and physical reactivity of CO2 within the pores. Computational modeling approaches, based on density functional theory (DFT) and van der Waals-DFT, have been applied to nanoporous solid – manganese dioxide a-MnO2. We found that the types and charges of cations as dopants in the a-MnO2 and the concentration of CO2 influence the structural features of a-MnO2, which control its CO2 selectivity performance within the flue gases.IntroductionCarbon capture and storage is a technique to separate large quantities of CO2 from power plant flue gases before being released into the atmosphere. Porous solids are a potential candidate as sorbents to “trap” CO2 through chemical or physical adsorption on their porous surfaces[1]. Such separation efficiency is determined by the size and shape of its pores and by the interaction between the porous surface and the gas adsorbates. The incorporation of cations into the pore can act as a means of structural support and alter the pore diameter to be comparable to the kinetic diameter of the gas adsorbate, such as CO2.A porous solid of particular interest for CCS is manganese dioxide a-MnO2, an octahedral molecular sieve (OMS) composed of edge-sharing MnO6 octahedra that are linked into a nanoporous framework[2]. The framework consists of (1×1) and (2×2) tunnels, referred to as OMS-2. Due to the larger tunnel size, cations and gas adsorbates prefer to reside along the (2×2) tunnel axis of the OMS-2. As seen in Figure 1, a potassium cation K+ is located in the (2×2) tunnel, known as cryptomelane-type MnO2. Its pore diameter of ~ 4.6 Å gives it a good CO2 selectivity performance, because the diameter is comparable to the kinetic diameter of 3.3 Å for CO2[3]. Alternatively, replacing potassium K+ with other cations, e.g. barium Ba2+, sodium Na+ or lithium Li+, in the OMS-2 tunnel is of great research interest, due to the effects of their concentrations, types and charges on the CO2 selectivity efficiency and sorption hysteresis phenomenon[2,4]."

Jan 1, 2014

By G. Ramadorai

"This paper addresses processing options for recovering gold from carbonaceous sulfidic gold ores. These include, but not limited, to the following methods: (1) Hypochlorite pretreatment followed by cyanidization; (2) Chemical blanking agents pre-treatment followed by cyanidization; (3) Non-cyanide heap leaching techniques; (4) biological pre-treatment followed by cyanidization; (5) biological pre-treatment followed by non cyanide heap leaching. Issues of costs, economics, recoveries, testing methods, state of advancement etc., will be discussed in the paper.ABSTRACT ONLY"

Jan 1, 1997

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