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By D. Rylander

The operation of Quarry and Aggregate sites are similar to factory production, since it contains sequential production processes, tasks and activities to produce the output product. Compared to the plant though, the quarry processes are generally not synchronized and controlled towards the overall throughput of the site in real time. Some quarries control parts of the production but do generally not utilize real-time technologies for the whole site and all its activities. This fact indicates a general improvement potential in increased productivity at quarry sites, but also unsolved challenges for the same reason. The main contribution of this paper is the presentation of a Lean based method for how to describe the processes to identify control improvement potential within a site. The aim of the identified improvements is to increase overall site productivity by optimizing site, fleet and machine utilization towards the overall throughput, and minimizing operational expenses and inventories. Further the paper exemplifies the method?s usability with field studies at operational quarry plants successfully identifying and quantifying potential wastes and improvements. In addition the identified productivity improvements based on increased control and automation indicate challenges and needs in wireless communication and sensing technologies.

Aug 1, 2013

By R P. Douglas

During 1955, Cominco commenced an exploration pro-gram in northern New Brunswick; in the following year, what is now the Wedge mine was discovered. The mineralization is mainly pyrite, with associated chalcopyrite and minor amounts of sphalerite and galena. The property was brought into production at 750 tons per day in early 1962. The ore is trucked 10 miles to the Heath Steele concentrator, where a copper concentrate grading about 19.5 per cent is produced and shipped to the Japanese markets through the port of Dalhousie, New Brunswick. Introduction THE Wedge mine, owned by The Consolidated Mining and Smelting Company of Canada Limited (Cominco), is located in the Newcastle-Bathurst area of New Brunswick. It is 42 miles by road northwest of Newcastle and 37 miles southwest of Bathurst (Figure 1). The mine is located on the north side of the Nipisiquit river in one of the more mountainous areas of the Province, the local relief rising to 1,500 feet above sea level. There is an almost complete forest cover of mixed hardwoods and conifers -the val-leys and hillsides being covered by balsam, spruce and pine, the swamps by cedars and black spruce and the highlands by mixed hardwoods.

Jan 1, 1965

By J. A. du Plessis, C. Dorfling

Selenium, tellurium and other precious metals (OPMs, namely Rh, Ru and Ir) dissolve in the final leaching stage of base metal refineries. Se and Te are typically removed from the copper sulphate leach solution by precipitation with sulphurous acid. Recovery of dissolved OPMs is desirable because it will reduce OPM inventory and losses. Thiourea is an effective OPM precipitation reagent, but yields insufficient Te removal. Copper is known to enhance Te precipitation when using sulphurous acid as precipitation reagent. The primary objective of this project was to evaluate whether simultaneous precipitation of Se, Te and OPMs using thiourea with metallic copper as precipitation reagents is possible. Batch precipitation tests were performed to evaluate the effect of temperature (50 – 70°C), thiourea addition (160 – 430% excess) and copper addition (2 – 8 g/L) on Se, Te and OPM precipitation. Increasing the temperature from 50°C to 70°C resulted in an average increase of 55.6 percentage points for Se precipitation and 13.5 – 23.5 percentage points for OPM precipitation. The copper addition did not have a significant impact on the precipitation behaviour. Increasing the thiourea addition increased the precipitation of Se and Te, especially when the copper addition was low; Rh and Ru precipitation also increased with up to 10 and 12 percentage points, respectively. Despite these observations, the precipitation of Se was significantly faster when no thiourea was added. It is not currently clear why thiourea appears to inhibit the Se precipitation by reaction with metallic copper. In general, Te precipitation was low (less than 30%) at the conditions investigated. Simultaneous precipitation of Se, Te and OPMs at temperatures below 80°C does not appear to be a viable option; a multiple stage operation for sequential removal of Se and Te with copper followed by OPM precipitation with thiourea would be required.

Jan 1, 2016

By H. R. Stockford

"A pyroxenite-carbonatite complex containing extensive pyrochlore mineralization was discovered during January, 1966, within an exploratory license area held by Consolidated Morrison Explorations Limited. Located 32 miles south of Moosonee, Ontario, the deposit was found under 100 feet of glacial till and Paleozoic sedimentary cover using airborne and ground magnetometer surveys. Exploratory and detailed drilling, totalling 47,625 feet in 85 holes, was completed in outlining the deposit to a maximum depth of 900 feet. Pyrochlore reserves are estimated at 62,000,000 tons averaging 0.52 per cent Cb,05 to a depth of 825 feet. Included in this tonnage is a high-grade section containing 10,000 tons per vertical foot grading 0.82 per cent Cb20 5• The deposit is still open at depth and the intrusive complex has by no means been fully explored.The columbium (niobium) mineralization occurs in a lineated calcite-dolomite host rock which has been intruded along a fault zone within a northeast-trending granulite belt. Potassium-argon dating indicates an age of 1655 million years.Preliminary studies suggest that the complex was intruded in a series of pulses in the form of a partially crystallized mush. The James Bay intrusive is unusual in that it is linear in form and contains only two main rock types - p•yroxenite and carbonatite. Nepheline-bearing syenites and associated rocks are notably absent. Moreover, the pyrochlore is essentially non-radioactive and free from many of the impurities generally associated with other pyrochlores. A test shaft to investigate soil conditions and to provide a 250-ton bulk sample was completed during 1968. Subsequent pilot-plant operations indicate that good quality pyrochlore concelttrates can be produced from this deposit."

Jan 1, 1972

By K. C. Corin, Z. G. Song, J. Y. Liu, M. W. Zhang, State Key Laboratory of Mineral Processing-BGRIMM, J. G. Wiese

"In the present study effect of grinding media on flotation of two mineral systems have been investigated, viz. sulphide minerals (including a pure chalcopyrite and pyrite mineral, and two different base metal sulphide ores), and oxide minerals (quartz, hematite and cassiterite). It was shown that mild steel media milling produced lower recoveries in the case of chalcopyrite and pyrite, as compared to the case of milling using ceramic media. For oxide minerals, the effects of using mild steel media as opposed to ceramic media were not as significant as was for the sulphides, although, after mild steel milling, at acidic pHs their recoveries were significantly reduced. For two base metal sulphide ores, viz. Nkomati and Dexing ores, the differences resulting from different milling media , although marginal, were opposite for each of these ores.For oxide minerals XPS showed that oxides and hydroxides of iron (e.g. FeOOH) adsorbed on the surfaces of the minerals. In the case of the Nkomati ore, adding Fe2+ or F3+ ions after milling with chrome steel media resulted in reduced talc (gangue) recovery, but increased water recovery and reduced concentrate grades. Further investigations are currently in progress to examine the Fe ions effect on the talc surfaces and froth properties.INTRODUCTIONGrinding of ores is necessary to liberate the valuable minerals from its gangues to allow for their selective recovery during mineral processing such as flotation. The grinding process inevitably involves contact of the ores with the surface of the grinding device and the grinding media. Accompanied by grinding, several phenomena can occur including the grinding medium wear, formation of precipitated species on the ore surfaces, chemical reaction, galvanic effects, changes in the Eh of solution, etc. There is a considerable body of literature on the differences observed in the flotation of various ores after milling using various grinding media. Laboratory studies have used balls or rods made from mild steel, ceramic, stainless steel or chrome steel to investigate the effects of different grinding media on mineral flotation. It is found that the interactions between the ore and the grinding environment can affect flotation separation of sulphide (Wei and Sandenbergh, 2007; Bruckard, 2011), oxide (He et al., 2014) and carbonate minerals (Song, 2009 and 2010). For example, mild steel milling produces relatively high concentrations of Fe ions in the pulp, affecting the recoveries of minerals compared to the case of ceramic media. On the other hand, the stainless steel media or chrome media are reported to be beneficial to the recovery of sulphides, when compared to the cases of using mild or carbon steel media (Rey and Formanek, 1960; Peng et al., 2003a,b; Huang and Grano, 2006; Bruckard, 2011). It is not clear, however, whether these Fe ions may affect the surface properties of the minerals involved or the general pulp/froth behaviour and hence their floatability. In addition, in the study of an low-S PGE ore carried out by Miettunen et al. (2012), forged media grinding in the CO2 atmosphere led to the highest Pt and Pd grades and recoveries, but the high chrome grinding media gave lower flotation recoveries than those using the forged media."

Jan 1, 2016

By S. Steinlechner

"Today the common recycling technologies of automotive catalysts are either energy intensive pyrometallurgical processes generating huge amounts of residues or hydrometallurgical ones which have to cope with effluent problems. Next to that, other valuable metals beside PGMs such as rare earths from the wash coat are not recovered.Therefore, the present paper introduces a hydrometallurgical concept developed in cooperation with the company Railly & Hill for the recovery of the PGMs as well as cerium from the wash coat of the catalysts in a closed loop. Next to the process concept, the required parameters for the different steps are discussed, including the chemical reactions, leaching efficiencies and mass flows, which form the basis for an economic estimation of the concept.Contrary to the pyrometallurgical recycling where the monolith is completely melted down to slag which is typically dumped, in this process the remaining monolith forms an utilizable product for the ceramics/refractory industry. As a result of the closed loop of the leaching media an environmentally friendly process was developed from which nearly no new residues or effluents are generated, with a sustainable usage of chemicals."

Jan 1, 2014

By K. Ihara, T. Yamaguchi, K. Matsumoto

"Al-Fe alloy sheets having layers with different strain components were produced by unlubricated hot rolling and the recrystallization texture formation during annealing was investigated in each layer. In this study, the strain component introduced by rolling was quantitatively evaluated by measuring degree of bending of an aluminum pin embedded in the sheet. The textures before and after annealing were investigated by the SEM-EBSD technique. It was clarified that, in the middle layer, where comparatively small shear strain was introduced, ß-fiber subgrains and cube {001}<100> oriented subgrains were formed before annealing, and cube oriented recrystallized grains grew after annealing. On the other hand, in the surface layer, where large additional shear strain was introduced, shear texture components and cube oriented subgrains were formed before annealing, and shear texture was retained even after annealing, while cube oriented subgrains did not grow and were encroached. It was suggested that introduced strain components influenced the recrystallization texture formation by inducing different distribution of the subgrain size, stored strain energy and orientation relationship with surroundings before annealing.INTRODUCTION The microstructure developed during the hot-rolling process of aluminum and aluminum alloys affect the mechanical properties of the final product sheets. Especially, the crystallographic orientation in the final product sheets affects the r- value and ears during deep drawing (Humphreys & Hatherly, 2004), then the texture control in the hot-rolling process is important. When the friction between the rolling roll and rolled sheet in the hot-rolling is large, both the rolling texture and recrystallization texture tend to be heterogeneous in the thickness direction. It is known in many rolled aluminum alloy sheets that the texture in the surface layer was different from that in the middle layer because of additional shear strain. It was reported that in the vicinity of the surface layer, where large additional shear strain was introduced, the shear texture <1 1 1>//ND and < 1 1 0> // RD which contain components of {1 1 1} <1 1 0> and {0 0 1} <1 1 0> developed during rolling, and the shear texture developed even after recrystallization annealing (Sakai et al., 2002). Particularly, it is thought that the <1 1 1> // ND texture contributes to improve the r-value and press formability (Inoue & Takasugi, 2007). Therefore, asymmetrical rolling and high friction rolling have been applied to improve formability of aluminum alloys by adding shear strain in the rolled sheets as deep as possible (Kamijo et al., 1972; Inoue et al., 2005). However, few researches have been focused on the microstructures and texture before annealing and thus, the detailed mechanism is still unclear how the texture after annealing is affected by the texture before annealing. In this study, the Al-Fe alloy of commercially pure aluminum was chosen as the first material to be studied in order to clarify the fundamental process of the recrystallization texture formation. The main purpose of this study is to clarify the effect of additional shear strain on the rolling and recrystallization textures in the hot-rolled sheets by analyzing the transition of microstructure and orientation distribution through recrystallization annealing."

Jan 1, 2018

By H. Huang, R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic to neutral solutions, over the pH range 1-7, to determine a potential range for co-dissolution. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated EH-pH diagrams for the copper-arsenic-sulfur-water system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Jan 1, 2014

By Stanley W. Holmes

"The discovery of extensive uranium mineralization on the Pronto property in April 1953 initiated a program of staking, exploration, and development unparalleled in Canadian mining history. Within twelve months of the discovery hole, sufficient ore had been blocked out to merit a 55-million-dollar contract with Eldorado Mining & Refining Co. On October 15, 1955, two years and four months after discovery, Pronto went into production with a mill rated at 1,000 to 1,500 tons per day. The property is on the southern edge of the Algoma uranium district, 10 miles east of the town of Blind River and close to the Canadian Pacific Railway and Highway 17. Docking facilities for Great Lakes steamers are avail-able at Spragge, 4 miles to the east.The data and conclusions presented in this paper are based on field studies, drill hole information, and underground development. The ideas of ore genesis are those of the writer, and will undoubtedly be modified as more detailed studies and research are carried out. Because of security regulations, information pertaining to grade and tonnage will not be discussed.GeologyThe general geology of the Algoma basin has been outlined in a pre-ceding paper (Joubin and James). The description below is concerned essentially with the rocks most closely associated with the Pronto deposit. They may be grouped in three structural and lithological units: (1) the pre-Huronian basement, (2) the Mississagi formation, the lowest member of the Huronian sediments lying unconformably on the basement, and (3) a series of basic intrusives cutting (I) and (2). Most of the uranium mineralization occurs in a quartz-pebble conglomerate forming the basal member of the Mississagi quartzite."

Jan 1, 1949

By Alireza Golabchi

The AEC (Architecture, Engineering, Construction) industry is an information intensive industry and all related processes employed during different phases of a project, including planning, designing, building, manufacturing, occupying, and maintenance, involve vast amounts of data that is used for a wide variety of purposes. Building Information Modeling (BIM) is a powerful shared knowledge resource which stores this data to support decision making about a facility through all these different phases in its life cycle. Nowadays, BIM is mostly used in the design and construction phases while it can also be highly beneficial beyond those stages. For example, in the Operation and Maintenance (O&M) phase, BIM could be used for automated facilities management or robotic inspection to provide semantic knowledge for navigation. For any implementation not related to the original intent of the BIM (design), organizations need to be able to represent their project data in a common interpretable form, which provides the possibility of an accurate exchange of data among different software products and platforms, known as interoperability. This study has investigated the current state of interoperability between software products used as Building Information Modeling tools. The main focus has been on a popularly used format for BIM models, Industry Foundation Classes (IFC), since it has been specifically developed to enable standardized data exchange. The research methodology involved a comprehensive literature review and the gathering of all fragmented prior research related to the field in order to develop a consistent understanding of the current state of knowledge. This was accompanied with a detailed case study that evaluated and compared two dominant pieces of BIM software, Revit and Bentley, and examined their interoperability strengths and weaknesses while using the IFC format.

Aug 1, 2013

By Douglas Brand

"The data that many mineral processing plants make use of, is provided by samples taken from sampling systems which are inadequately designed or improperly maintained, and therefore cause detrimental effects to plant operations, production planning and metallurgical accounting! Poorly designed or maintained sampling systems will likely produce low probability samples which give the operator a false sense of security of the product and the process. If data is the basis for action (Flintoff, 1992, p.2), then using the resulting suspect or bad assays by operators, control systems, or metallurgist and administration personnel will act and make decisions which may adversely affect the profitability of a processing plant. Here we will discuss some of the fundamental sampling problems, propagation of errors and a method to estimate what impact this has on an operations Net Smelter Return.INTRODUCTIONIn order to control a mineral processing plant at its best potential, it is necessary to obtain the best possible measurement results of the metal or mineral in question. The sample which is delivered to a measuring instrument, or lab, needs to be of the highest probability to be able to achieve this. This paper will discuss the effects of sampling errors on grade / recovery and grade / Net Smelter Return (NSR) and provide a method to estimate the monetary advantages of using probabilistic sampling in a processing plant.REVIEW OF SAMPLINGSampling, by definition, is the removal of a small representative portion from a total consignment, or flow, for the purpose of accounting or process control.• A sample can only be considered representative, if each and every increment collected, in each of the sampling stages, is representative.• Each particle of the sampling lot must have the same probability of being included in the final sample.• If both of the above conditions are met, then the final sample will be representative of the complete sampling lot.It is commonly known that in order to take truly representative and probabilistic sample, best practices indicate that:• The total stream should be sampled.• The sample cutter should intersect the sample at right angles to the flow.• The sample cutter should travel through the stream at a linear and constant speed and the speed deviations should be less than 5%."

Jan 1, 2016

Access to accurate real-time information is critical to maintaining efficiency and competitiveness in any modern minerals processing facility. At MMG LXML Sepon Copper Operation in Lao P.D.R., controlling the copper grade of the feed to the leaching circuit is paramount for maximising productivity and copper recovery. Since 2008, real-time analysis data has been available to process engineers from the Geoscan on-belt analyser installed on the Copper Mill feed conveyor. Access to accurate real-time results from the Geoscan has allowed the process engineers to strictly control blending based on copper grade to overcome variability in the plant feed, where conventional sampling and laboratory analysis is difficult, error prone and time consuming. In addition to enjoying these benefits since the Geoscan’s installation, in recent times the process engineers have expanded the use of the Geoscan by observing elemental results other than copper grade to control different aspects of the operation, focussing on the reduction of Gangue Acid Consumption. This paper discusses the process of expanding the Geoscan use at the operation, including an explanation of the calibration process. Additionally, a brief description of the Geoscan and its use at MMG LXML Sepon Copper Operation is provided, as well as a summary of recent calibration and analysis results. A discussion of future works concludes the paper.

Jan 1, 2016

By A. Alfantazi, E. Asselin

"The corrosion of commercially pure titanium (CP-Ti) was studied from room temperature up to medium temperature (~160°C) under conditions relevant to medium temperature chalcopyrite leaching processes. The corrosion rates were measured by immersion and electrochemical tests in sulfuric acid. The influences of chloride, cupric and ferric ions on the corrosion rate and behavior were also investigated. Corrosion of the CP-Ti did not account for the total current density measured by linear polarization tests. The corrosion rates of CP-Ti under medium temperature leaching conditions were surprisingly high. The corrosion rate measured in ferric containing solution at 160°C was approximately 20 mm/yr.INTRODUCTIONTitanium exhibits excellent corrosion resistance in many aggressive environments because of the formation of a very chemically stable, highly adherent, and protective oxide film on its surface (Mitsuo et al., 2002). Because titanium is the only metal available at a reasonable cost that resists the high temperature corrosive slurries in many leaching processes, it is often chosen as autoclave liner material where it is subjected to severe conditions of acidity, temperature and pressure (Grauman and Say, 2000).A number of distinctly different hydrometallurgical processes for the pressure leaching of chalcopyrite have been developed and patented by various companies and they can be classified into low, medium and high temperature regimes (McDonald and Muir, 2007). For example, chalcopyrite concentrate may be processed at medium temperatures (115-175°C) and pressures of 800-2200 kPa (Dreisinger, D., 2006; Sahu and Asselin, 2011). The lixiviant may contain 20 to 55 g/L sulfuric acid, 8 to 12 g/L chloride ions, 10-25 g/L Cu2+ (Jones, 1995, 1997, 1999), and less than 1 g/L Fe3+ (Defreyne et al., 2005). The amount of these additions is determined by the grade of the ores and details are shown in Table 1."

Jan 1, 2012

By J. Mcdvcka

Sustainable development has become a driving imperative for the resource industry as it is for the rest of the global business world. Being unsustainable is a risk no business can afford. Yet implementation of sustainable development practices beyond satisfaction of compulsory reporting is still sporadic. The current standard approaches to problem analysis and decision making are too narrow to capture the complexity of the issues at stake. Hence it is necessary to develop innovation in thinking and in doing. Those who search for ways to implement sustainable development use concepts such as Whole Systems Thinking and Eco-efficiency as well as tools like Life Cycle Analysis. Others develop their own instruments. In their effort to innovate they face both resistance and support within their organisation as well as within the industry or the wider context. This paper explores the factors that support, hinder and shape the sustainable development drive of the industry and proposes a comprehensive decision-making framework that links the goal of sustainability with the tools of sustainable development. This exploration is illustrated by a case study used in a doctoral research conducted on an engineering firm providing services to our industry.

Jan 1, 2007

By D. P. Ziegler

Formulas relating economic optimum busbar cross sectional areas to busbar cost, electric price and financial parameters are reviewed and revised. Application of the formulas is illustrated with discussion of the appropriate choice of parameter values and the sensitivity of the optimum to the parameters. The extension of the single busbar concept to optimization of more complicated arrangements of bus for smelting pots is complicated by the constraint of obtaining a specified current distribution. An example problem illustrates the optimization of a section of a bus network containing a fork, with the imposed limitation of achieving a specified uniformity in the current. In cases where the current in the individual conductors may vary, Kelvin&apos;s law does not apply. Further extension of the technique to a full pot set of conductors poses additional problems which are discussed, but whose solution has not yet been accomplished. Aluminium 2006 45th Annual Conference of Metallurgists ofCIM Montreal, Quebec, Canada Edited by

Jan 1, 2006

By Curtin University Western Australian School Mines

"Curtin University’s Gold Technology Group has developed an online CIP/CIL simulation model called SIMCIL which has been used since 1999 to model and simulate industrial leach-adsorption circuits. Recently the model has been upgraded to include an integrated liberation-leach modelling (ILLM) approach which can be used to evaluate the impact of various process parameters (such as grind size, bleed to gravity etc.) and circuit configurations on leach-adsorption circuit behaviour and overall plant gold recovery. A new time-efficient ore characterisation methodology has been researched and developed to provide the required liberation-leach data used in the ILLM approach, which is implemented online for the modelling of gold operations. The model structure, modelling approach, and some scenarios are discussed.INTRODUCTIONCurtin University’s Gold Technology Group has developed an online CIP/CIL simulation model called SIMCIL which has been used since 1999 to model and simulate industrial leach-adsorption circuits. The model has recently been upgraded to include an integrated liberation-leach modelling (ILLM) approach. The ILLM approach provides the means to evaluate the impact of the gravity recoverable gold (GRG) characteristics of the ore (GRG content and liberation behaviour), various process parameters (such as grind size, bleed to gravity, etc.) and circuit configurations on the gravity gold recovery, leachadsorption circuit behaviour and overall plant gold recovery.A new time-efficient ore characterisation methodology has been researched and developed to provide the required liberation-leach data used in the ILLM approach. The data required for the ILLM calibration can be obtained directly from the 3 stage GRG test, leach tests and size-by-assay analysis of the 3 stage GRG test products, and leach test products.This paper describes the ore characterisation methodology, model structure, modelling approach, and the application of the ILLM."

Jan 1, 2016

By C. A. Morais, L. V. Resende

"The technological development observed in recent years has stimulated the application of rare earth (RE) elements. Amongst their various applications it is well worth mentioning their use in electronics, superconductors, nuclear medicine, as well as in special inks - as those used in radar invisible airplanes. TV and computer monitor screens present as coating a powder containing some rare earth elements, mainly Europium and Yttrium. The recovery of the RE elements from electronic scrap is extremely important as the economic and environmental issues are concerned. This paper describes the study of the Eu and Y recovery from e-scraps. The first step of the process was the leaching of the powder obtained by manually scraping the inside surface of the screen. After the optimization of the leaching, the dissolution of Eu and Y was higher than 98 w/t% and a pregnant sulfuric liquor containing 11.9 g L-1 Y and 0.72 g L-1 Eu was obtained. The second step was the separation of the metals found in the liquor by the solvent extraction technique. The separation of Eu and Y was carried out in a counter current circuit compound of 3 extraction stages, 7 scrubbing stages and 15 stripping stages. DEHPA was used as the extractant, whereas a diluted sulfuric acid solution was applied as scrubbing agent and a hydrochloric acid solution at high concentration was used as the stripping agent.INTRODUCTIONThe rare earths (RE) are a moderately abundant group of 17 elements composed of lanthanides, scandium and yttrium. Amongst the RE, promethium (Pm) is extremely rare, however several of the RE elements are not very rare and occur dispersed in a variety of forms (Greenwood & Earnshaw, 1984; Tyler, 2004).The innumerable applications of the RE elements are based on their particular properties, mainly their spectroscopic and magnetic properties (Martins & Isolani, 2005). The technological development observed in recent years has stimulated the application of rare earth (RE) elements. They have been used in agriculture, electronics, superconductors, nuclear medicine, automobile industry, special inks – as those used in radar invisible airplanes, X-ray screens, high intensity mercury vapour light bulbs, neutron scintilators, charged-particle detectors and optical memory reading systems (Maestro & Huguenin, 1995; Nagaosa & Binghua, 1997; Sánchez et al., 1999)."

Jan 1, 2012

By P. S. Arthur, G. R. F. Alvear

Development of a new smelting process is risky. Many novel processes in the metals industry failed to fulfil the initial expectations of their inventors. Large sums of capital have been invested in technologies that either didn&apos;t provide a satisfactory return on investment, or didn&apos;t perform at all, and had to be replaced. One of the keys to success in process development is incremental scale up of the technology, with potential problems being identified and rectified as early as possible. In this way the cost of any rectification that is required can be minimized. The ISASMELTTM process was developed to maturity by Mount Isa Mines through the 1980&apos;s and 1990&apos;s using incremental scale up. Commercialization only occurred once the process had been proven on laboratory, pilot and demonstration scale over many years. As a result ISASMELTTM technology now operates successfully at numerous plants around the world. The methodical approach to development of the technology has allowed owners to modernise their existing operations or create new businesses with significantly reduced technical risk.

Jan 1, 2011

By Martin Bouchard, Bruno Paillard, Jean-Claude Dubé, André L’Espérance

"A precise analysis of the noise emitted by an aluminum plant has shown that one of the main sources of noise is the noise emitted by an exhaust stack 40 m high and 1.8 m diametre, emitting a pure tone at 320 Hz. Because a classical cost effective solution is not available for this source, active noise control (ANC) solution was investigated.Commonly available ANC systems, how-ever, are not applicable to the chimney considered because the diameter of the stack (f) is too important compared to the wave length(?)of the frequency to control. In fact, until now, active noise control (ANC) has been successfully used to reduce the acoustical energy emitted at the end of ducts in the case of plane wave propagation, i.e. ?/f< 1.7 [1,4].When f> ?/1.7, high order modes propagate in the duct and a single canal active noise control system is not sufficient.This paper presents an ANC system developed to control higher modes in a circular duct. The controller used is based on a multiple-input, multiple-output adaptive filtered X-LMS and allows up to 11 error micro-phones and controls sources. The system has been used in a laboratory on a finite duct of3.5 m long and 0.30 m diameter which corresponds to the same ratio ?/f for the real stack. The efficiency of the system with different numbers and location of control sources and errors sensors has been analyzed. Noise reduction of 15 dB(A) could be obtained with some configurations. Actually, the system is being considered for installation on the real chimney stack."

Jan 1, 1997

By A. Jordens, Y. Zhiyong

"IMBSRE, one of the largest rare earth element (REE) producers in China, produces a rare earth oxide (REO) concentrate as a by-product by floating the middlings stream from a low intensity magnetic separation step in the main iron ore processing stage. As the mine depth has increased, flowsheet changes in the main iron ore circuit have reduced the REO grade and increased the magnetite to REO ratio in the middling product used as flotation feed for the REO circuit. Extensive laboratory work was carried out and identified a new modified hydroxamic acid product, Florrea 8920, that could provide better metallurgical results over the standard hydroxamic acid used as the main collector. This paper briefly reviews the use of hydroxamates in the flotation of oxide minerals, provides detailed information on the different hydroxamates available from Florrea and then provides a case study of the successful implementation of the Florrea 8920 product in a commercial Chinese REE flotation plant. The case study consists of a one year program of pilot plant testing and industrial trials to confirm the results of laboratory tests. The implementation of the new collector resulted in an improvement in grade and recovery to 61% and 64% respectively. The new collector also provided significant economic and environmental benefits.INTRODUCTIONThe flotation of rare earth element (REE) bearing minerals is a topic which has been dominated in the English language literature by the work conducted on the Mountain Pass bastnäsite deposit (Pradip, 1981; Fuerstenau, Pradip, Khan, & Raghavan, 1982; Pradip & Fuerstenau, 1983, 1985, 2013; Fuerstenau & Pradip, 1991; Fuerstenau, Pradip, & Herrera-Urbina, 1992; Herrera-Urbina, Pradip, & Fuerstenau, 2013). By far the most important collector type used for the flotation of rare earth minerals (REM) is hydroxamates. These reagents were initially extensively described as REM collectors in the English literature by Pradip (1981) however they have been successfully applied to numerous other minerals such as: cassiterite (Sreenivas & Padmanabhan, 2002); pyrochlore (Gibson, Kelebek, Aghamirian, & Yu, 2015); hematite, chrysocolla, rhodonite, hubnerite and pyrolusite (Fuerstenau, 2005); and malachite (Lenormand, Salman, & Yoon, 1979) amongst others."

Jan 1, 2016