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By T. Patching

"Introduction The occurrence of coal was first reported in the Drumheller area in 1793 but it was not until 1912 that production of coal was recorded. In that year 13,000 tonnes were mined in the Drumheller area. Three years later the Drumheller mines ranked next in the Province to those in the Crowsnest and Lethbridge districts, with an output of 225,000 tonnes. By 1917 production had increased to 600,000 tonnes, moving Drumheller to second place in output in the province, second only to the Crowsnest district. It held this rank until 1960. Production, almost all from underground mining, rose to over a million tonnes a year by 1920 and remained between one and two million tonnes per year until 1954. Competition from newly discovered oil and natural gas, beginning around 1950 caused a steady loss of domestic coal markets, especially from underground mines. By 1960 Drumheller's production had fallen below a half a million tonnes per year and the field ranked third in output in the province, being surpassed by new stripping operations in the Castor field. By 1965 only a couple of producing mines remained in the Drumheller valley, and output was only about a quarter of a million tonnes per year(1). Throughout the life of the field production was seasonal, depending mainly on the domestic heating market. In 1979 the last mine ceased production. For the last several years of its operation it had remained open in the summers to provide tours for visitors(2). The Drumheller mining operations were located along or near the Red Deer River valley which is 300 to 400 feet deep, and extended from a few miles above the city of Drumheller to East Coulee, about 13 miles down the river in a south-easterly direction. Intervening mining communities existed for some years at Wayne and Rosedale. During the peak years of production some 2000 to 2500 miners and their families lived in these communities and the surrounding areas."

Jan 1, 1985

By A. Gauthier, J .. E. Muir, M. Cormier

Falconbridge's Lac Shortt gold deposit is located in Gand Township, some 25 km north-east of Desmaraisville, The deposit was outlined in i980 by a drilling program me conducted by Falconbridge Ltd. in a joint venture with Corporation Falconbridge Copper after three years of systematic exploration by Falconbridge Ltd. in the Desmaraisville area. The gold bearing structure had previously been drilled by three other exploration companies. As based on an underground development programme conducted by Corporation Falconbridge Copper, the "in-si tu" mineral inventory to a depth of 500 metres at a cut-off grade of 3.0 g/t is estimated at 1 937 605 tonnes at a grade of 6.4 g/t (uncut) and 6.0 g/t (cut). Regionally, the stratigraphy consists of thick sequences of volcanic and volcanosedimentary rocks intruded by numerous and voluminous mafic (gabbro), felsic (granodiorite, syenite) and anorthositic intrusions. Structurally, at least two fold sets and one major fault system (E-NE) are present. Minor fault systems oriented E-NE and N-NW also occur. Mine stratigraphy can be divided into 1) - the hangingwall; 2) - ore zone; 3) - footwall. Hanging wall rocks include: a) green lapilli and blocky tuff b) transition zone c) green mica crystal tuff and d) red dolomitic tuff. Ore zone rocks include: a) bleached mafic tuff b) barren carbonates, c) pyritic dolomitic tuff (?) and d) brick-red syenite. Footwall rocks include: a) magnetic lava (so-called diorite), b) mafic lapilli and blocky tuff and c) alkali basalt, Native gold is the only gold mineral so far identified and it occurs both as free grains in gangue and as micro-inclusions in pyrite. Two geochemical groups were identified in the main rock units: 1) Alkali-rich rocks cons is ting of the ore zone and foot wall rocks and 2) Subalkaline group consisting of the hanging wall rocks. Ore analysis also shows Ba, Sr, W, Zr, REE and F enrichment in the ore zone. Footwall rocks are enriched in Na20. Present geological and geochemical data do not permit a clear interpretation of the formation for the Lac Shortt gold deposit but suggest it is a volcanic-hosted stratabound type. The bulk of the mineralization is associated with an exhalative phase following alkalic, carbonic, hydrothermal activity and part of the mineralization is associated with a late intrusive phase.

Jan 1, 1984

"The pressure leaching of alkali-pretreated limonitic laterite ore in nitric acid was studied. The optimal leaching conditions are as follows: leaching temperature of 458 K, initial nitric acid of 2.44 mol/L, leaching time of 60 min, liquid to solid ratio of 2:1 mL/g, agitation speed of 500 RPM. Under the above conditions, the extraction of nickel and cobalt can be achieved as approximate 95% and 80% respectively while that of iron is as lower as 1%. The leaching residue containing 70% of iron in the form of hematite and trace amount of chromium is suitable as the raw material for iron-making. The nitric acid in the leaching solution can be regenerated and further recycled to leach. INTRODUCTIONIt has been estimated that 60%-70% of the world land-based nickel resources presented in nickel laterites containing 130 million tons of nickel although these only accounted for about 42% of the world nickel production (Sudol, 2005; Luo et al., 2010). The nickel resource of laterite has not yet been fully utilized. Due to the increasing global demand of nickel and the declining global reserves of nickel sulphides, there is an increasing focus on the processing of the huge reserves of laterite ores today. Nickel laterite ores can be simply divided into two types, namely, silicate-rich and limonite. The former can be treated effectively by pyrometallurgical process in which the ferronickel product or nickel/iron sulphide matte is produced (Monhemius, 1987). The limonitic laterite is rich in iron in the form of goethite which is the main nickel-bearing mineral and usually contains cobalt associated with a manganese phase (Chang et al., 2010; Georgiou and Papangelakis, 2004). The limonitic laterite is usually processed by hydrometallurgical methods, such as atmosphere acid leaching (AL) (Xu et al., 2005; McDonald and Whittington, 2008), high pressure acid leaching (HPAL) (Chou et al., 1977; Georgiou and Papangelakis, 1998; Rubisov et al., 2000; Whittington and Muir, 2000) and reductive roasting-ammonia leaching (Caron Process) (Whittington and Muir, 2000; Valix and Cheung, 2002). The AL process can proceed at lower temperature, thus the operation costs may be very low. But two biggest problems associate with the AL process, namely, the slow rates of nickel extraction and potentially the significant amount of impurities such as iron and aluminum in the leaching solutions, which hampers the wide application of the AL process. The Caron Process uses the pyrometallurgical and hydrometallurgical methods together to obtain the metallic values, but the overall metal recovery is relatively low, especially for cobalt. In recent years, the environment-friendly process of HPAL has become increasingly important because it is most suitable for low-grade ores and leads to high extraction of the valuables. However, the HPAL process needs a much higher temperature and pressure (503-533 K, 4-5 MPa) to maintain a relatively fast leaching rates, which results in higher operation costs. Moreover, another serious problem of scale formation in autoclaves occurs in the HPAL process, for example, in Moa Bay, up to 20 cm scale may build up resulting in 5 days descale downtime per month. In addition, the iron residues cannot be utilized for ironmaking due to the presence of high content chromium (Ema and Harada, 1987; Owada and Harada, 1987; Takagi and Furui, 1987)."

Jan 1, 2012

By Sabine Noelte, Mikko Petteri Rantamäki, Christopher Robben, Anssi Takala, Karl-Erik Rånman

"Sensor-based ore sorting is on its way to establish as a standard option for physical separation. The increasing number of installations in coal, iron ore, industrial minerals and hard-rock metal mining segments underlines the technological and financial potential that is beginning to be untapped. The Ma’aden Phosphate installation with 1.650 t/h sensor-based ore sorter feed sets a new benchmark for the possible capacity of stationary installations. Besides stationary installations, including multiple sorters parallel in different size ranges and multiple stages, containerised semi-mobile plants are applied. These offer two advantages, first being the reduction of transport costs when applied close to the mining face. The second is that semi-mobile systems enable processing of tens of thousands of tonnes of ore in a piloting phase with an approximate duration of 0.5 to six months, verifying the results laboratory mini-bulk tests on 5–10 tonnes of sample. This is especially important for low-grade metal ores because of the inherent Fundamental Sampling Error, as well as the Grouping and Segregation Error. The paper elaborates the results achieved within the I2MINE project, treating polymetallic ore at the Boliden Concentrator in Sweden.INTRODUCTIONSensor-based ore sorting (SBS) is becoming a standard option for physical separation, applied in all segments of mineral production. The Umm Wu’al project sets the bar for stationary SBS installations with 1,650 t/h feed (TOMRA, 2015). TOMRA Sorting Solutions has finalised an agreement in cooperation with Outotec to supply Outotec-branded sorting solutions for the mining and metallurgical industry (TOMRA, 2014). Especially for low-grade hard rock metal ores, an interdisciplinary approach is necessary applying experts for all aspects of mineral production. Due to the impact on the whole process stream, it is important on the end user side to have high level managerial support and involve all disciplines to ensure that all stake holders are involved in the analysis."

Jan 1, 2016

By B. Yamamoto, D. Post, J. De Leon, A. Meike

"This paper describes the theory, design, building, and testing of the passive magnetic bearing stabilizing system which is the core of the passive magnetic bearing system. The stabilizing system is made up of two large magnetic disks opposing themselves with a stabilizing disk in the center which allows the system to self-locate in a null position without the need for external power sources or sensors. When outside forces act upon the stabilizer, the magnetic fields interact with the stabilizing plate to return the system to its null position. Collaboration between two industry leaders has allowed an actual prototype to be built and tested providing real data to prove out the theory.INTRODUCTIONMagnetic bearing/stabilizer systems have many advantages over conventional mechanical bearing systems. These include near-zero drag losses and no need for lubrication since the rotating elements make no mechanical contact with the stationary elements of the bearing system. However all magnetic bearing systems must contend with a constraint known as Earnshaw’s Theorem in the early 1800’s, this theorem asserts the impossibility of constructing a stable, non-contacting, electrostatic or magnetostatic levitation system using only fixed charges or fixed magnetic poles, such as those produced by permanent magnets. Because of the constraint imposed by Earnshaw’s Theorem virtually all present-day commercial magnetic bearing systems are of the “active” type. That is, they employ electromagnets that are powered by amplifiers the inputs to which come from sensors embedded in the bearing system. These sensors are a part of a feedback loop that operates to keep the levitated rotating parts of the bearing stable and centered. The resulting complexity means that active magnetic bearings are expensive, require periodic maintenance, and continuously consume electrical power to energize their amplifiers and their electromagnets.Passive magnetic bearings are, of course, also subject to the constraints imposed by Earnshaw’s Theorem but they solve this problem in a straightforward and simple way, with only “passive” elements that take advantage of a loophole implicit in the derivation of Earnshaw’s Theorem. This loophole is that Earnshaw’s Theorem as derived applies only to static systems, i.e. an assembly of stationary permanent magnets arranged so as to levitate an object containing other permanent magnets. The theorem can be overcome if dynamic effects are taken into account. In active magnetic bearings the “dynamic effects” involve the afore-mentioned sensors, amplifiers, and electromagnets."

Jan 1, 2012

By Brian W. Mackenkzie, Jozef Lajzerowicz

This paper is intended to familiarize planners in the noncommunist world with the district planning approach used in eastern Europe for mining development. It deals generally with the basic nature of the district planning problem, the planning process for mining development and the state organization for the planning of mining districts. A number of applications of district planning techniques to both established and new eastern European mining districts are described.

Jan 1, 1971

By A. E. Cameron

The theory of atomic distribution of the stranger atoms in the space lattice of the solvent metal has been well developed by Rosenhain. It has long been known that the addition of one metal to another to form a solid solution increases the strength and hardness of the solvent metal. This increase is practically proportional to the amount of added substance up to the limit of solid solubility. To account for this increase in hardness and strength, Rosenhain assumes that the stranger atoms occupy positions on the solvent metal space lattice. Atomic attractions about the stranger atoms will not be the same as in the case of the pure metal, and there will thus be a disturbance of the orderly arrangement of the atoms on the space lattice, or a distortion of the lattice. Such a disturbance would interfere with the ease of slip along the planes and would thus tend to promote strength and hardness. Rosenhain notes that not only may there be a local disturbance of the lattice about the stranger atom but there may well be also a measurable change in the dimensions of the lattice as a whole. The relative amounts of local and general distortion of the lattice will depend upon the nature of the lattice itself. As Rosenhain says, "If the lattice is comparatively soft and flexible the distortion is likely to be largely local. In a stiff lattice, however, local distortion will be resisted and there will be a correspondingly increased general distortion."

Jan 1, 1927

By Samantha A. Beeson, Colin Poole

"A selective flocculation-floe flotation technique is already in use in the Canadian potash industry for the removal of water-insoluble slimes, but the process is currently limited in its application and reagent consumption is high. The work described in this paper details investigations into the separation of sylvite and halite from water-insoluble slimes by selective flocculation utilising other commercially available polymers.Preliminary flocculation performance tests were undertaken on pure sylvite, halite and water-insoluble minerals to establish the importance of a number of experimental parameters. The data from these single mineral tests was then used to establish optimum parameters for the separation of sylvite and halite from a synthetic mixture similar in composition to a typical potash ore. Under optimum conditions, separation was achieved with high recoveries using dispersant and flocculant dosages significantly lower than those currently used in plant practice.IntroductionAlthough solar evaporation and solution mining are used in some operations, most potash is extracted by conventional underground techniques and is then processed by froth flotation, in order to separate the valuable sylvite (KCI) from halite (NaCl) and water-insoluble gangue minerals. Flotation is usually preceded by a desliming stage to remove water-insoluble fines, but this also results in high potash losses and affects process brine requirements. To overcome these problems, one plant operated by Cominco in Saskatchewan uses a selective flocculation -floe flotation process (Banks, 1979/1980), in which a polyacrylamide flocculant is added to produce floes of water-insoluble material with minimal incorporation of halides. A collector is then added to render the floes hydrophobic and suitable for removal by froth flotation.A number of workers have also investigated the use of selective flocculation in potash processing, but these too have been concerned with developments in the removal of water-insoluble slimes (Williams, 1960; Brogiotti et al, 1974; Chan et al, 1986; Thompson et al, 1979; etc.). This paper provides results of novel investigations into the selective flocculation of sylvite and halite from water-insoluble minerals and discusses the possible mechanisms involved."

Jan 1, 1995

By Long Han, Beijing General Research Institute of Mining and Metallurgy, Yu Xie, Yunhai Zhang, Yangge Zhu, University of Science and Technology Beijing, Yanbo Shang, Xingrong Zhang

"The first-principles method was employed to study the adsorption of hydroxyl calcium (CaOH+) and hydroxyl (OH-) on hematite and quartz surfaces. The calculation results suggested that OH- preferred to interact with the active Fe sites on the hematite surface, whereas OH- adsorbed on the quartz surface by weak hydrogen bond. Though CaOH+ could easily adsorb on the hematite and quartz surfaces by the formation of Ca-O bond, the covalence formed on the quartz surface was apparently stronger than that on the hematite surface, meaning a stronger and more stable adsorption. CaOH+ adsorbed on quartz surface was mainly through the interaction of O-2p and Ca-3d states, and this interaction on hematite surface was weaker.INTRODUCTIONIron Increase and Silicon Reduction Technology (Yu & Duan, 2002) of hematite is mainly through the reverse flotation (silica is floated away from the iron concentrate). There are two ways to achieve this (Houot, 1983). One is to collect quartz by cationic collector directly; the other is to activate quartz by lime and then collect it by anionic collector. There are two main different views with respect to the mechanism of quartz activation: mono-hydroxyl compound theory (Fuerstenau, Rice & Somasundaran, 1965; Fuerstenau & Palmer, 1976) and surface hydroxyl precipitation theory (Hu & Wang, 1988; Wang & Hu, 1990). The former indicated the formation of the mono-hydroxyl complex is one of the two criteria of quartz flotation. The later theory, on the other hand, suggested that surface precipitation is the adsorption of active species of metallic ion on quartz surface. However, most of those researches are based on the solution chemistry of flotation and little is done at the microscopic level.In this paper, by the help of first-principles calculations, the adsorption models, bonding conditions, Mulliken charge populations and adsorption energies of hydroxyl and calcium hydroxyl ions (OH- and CaOH+) on hematite (001) and quartz (100) surfaces were investigated to find out the lime activation of quartz at atomic level, which is significant for the researches of quartz activation theoretically and practically."

Jan 1, 2016

By W. Hawker, A. M. Ivana

"Pressure oxidation is used to liberate gold from refractory sulphide ore and concentrates with over fifteen autoclaves in operation. Despite the importance of pressure oxidation, the autoclave chemistry and chemical thermodynamics are not well established. For example, there is no consensus on aqueous iron speciation or stability of jarosite phases. Additionally, there remains questions about basic ferric sulphate formation and stability. In addition to a review of the current state of knowledge, a methodology to study the ferric precipitation reaction and relate the results to chemical thermodynamic predictions is presented which will be used to accurately define the phase boundaries of the iron precipitates in the future (hematite, jarosite and basic ferric sulphate).INTRODUCTION With declining availability of orebodies that respond to simple leaching conditions, pressure oxidation has become a prevalent technology to liberate gold locked in sulphide mineral matrices. Gold pressure oxidation was established 32 years ago, with McLaughlin being the first facility in 1985 (Thomas & Pearson, 2016). Pressure oxidation is carried out at elevated temperatures ranging from 180 to 240°C as shown in the summary of operations in Table 1 (Ruonala et al., 2016; Fleming, 2010).A considerable amount of research has been done to study iron solubility and precipitation under autoclave conditions (Tozawa & Sasaki, 1986; Umetsu et al., 1977; Sasaki et al., 1993; Fleuriault, 2016; Cheng & Demopoulos, 2004; Papangelakis et al., 1994; Yue et al., 2003). These reports provide a description of the process chemistry and iron behaviour in the autoclave. However, there remain questions about the type and stability of aqueous species and solid phases. This detailed information is required to build a robust chemical thermodynamic model of the system, allowing for equilibrium and kinetic reaction limitations to be discerned."

Jan 1, 2017

By G. B. Harris

A process for the recovery of copper from the waste oxide copper of a mined-out sulphide orebody is described. Hydrometallurgical recovery of copper from this and similar wastes has been tried several times previously without success. Leaching is carried out by sulphuric acid in columns under conditions that minimise the iron content of the pregnant leach liquor, and copper is then recovered by ion exchange rather than the more conventional solvent extraction. The resin is stripped by spent electrolyte and copper is electrowon. Results are presented for testwork originally carried out in 1993, and repeated in 2006, and the novel aspects of the process, leaching and ion exchange, are discussed. Finally, preliminary order of magnitude capital and operating costs are given, demonstrating that the process is cost effective.

Jan 1, 2007

By Tommee Larochelle, Henry Kasaini

"Simulation of rare earth element solvent extraction processes for plant design and optimization is complex, requires extensive bench scale and pilot scale testing, and is traditionally performed using proprietary algorithms. The complexity of simulation is mainly due to traditional simulation software solvent extraction modules not being designed to simulate rare earth separation processes because of the interaction between each element. This paper presents an alternative method for designing and optimizing rare earth element solvent extraction separation processes using METSIM to converge each stage of the battery individually until the full battery reached ultimate convergence. A feed-forward controller is used to control the organic to aqueous flow ratio feeding the solvent extraction modules. This method minimizes the complexity of simulating such processes by using inexpensive batch solvent extraction data, and allowing for rapid theoretical optimization, by varying the process configuration and parameters from a graphic interface instead of the traditional code-based interface of most proprietary models. Comparison of the model predictions to pilot plant data reveals that the method can be used to accurately model rare earth solvent extraction processes, as illustrated by its application in the development of Rare Element Resources innovative process.INTRODUCTIONThe Rare Earth Elements (REEs) consist of 16 metals, specifically the 15 lanthanide elements and yttrium, which is typically found in the same mineral deposits as the lanthanides. Scandium can be associated with the rare earth elements, but is usually only present in trace amounts, and therefore omitted. The term “rare earths” originates from an old term used to designate minerals (earths) and their believed scarcity upon their initial discovery. The rare earths designation is now considered a misnomer because it was demonstrated that the crustal abundance of some rare earth elements, such as cerium, is known to be higher than many common metals, such as copper. However, enriched deposits are fairly uncommon compared to other similarly abundant metals. The REEs are typically divided into groups commonly consisting of light rare earths (LREEs), medium rare earths (MREE), and heavy rare earths (HREEs). Light rare earth elements include lanthanum to neodymium, medium rare earths include samarium to gadolinium and the heavy rare earth elements include terbium to lutetium, and yttrium. The REEs exhibit similar chemical characteristics and are usually extracted from the ore and processed into a mixed rare earth concentrate. The rare earth concentrate requires further processing in order to separate the REEs from each other and produce a series of single element products."

Jan 1, 2016

By Gyeonghye Moon, Inhyeok Choi, Jyothi Rajesh Kumar, Jin-Young Lee

"This paper deals with the recovery of the tungsten and vanadium from spent SCR catalyst leach liquors by different hydrometallurgical methods. The first part consists of pressure leaching of spent SCR catalyst using caustic soda followed by metal recovery by liquid-liquid extraction. In a leaching process, the following experimental parameters were tested and optimized: NaOH, particle size of feedstock, temperature, and solid to liquid ratio. The optimum condition for leaching of tungsten and vanadium was under the following conditions: NaOH 3 mol/L, temperature 250°C, particle size <300 µm, and solid to liquid ratio 0.4. From these optimum conditions in this experiment, the dissolution efficiency of vanadium and tungsten was 91.5and 87%, respectively. Liquid-liquid extraction following commercial extractants were tested: TBP, Cyanex 272, D2EHPA, Aliquat 336, Primeme JM-T, Alamine 308, Alamine 304-1, and methyl-tri-octyl-ammonium chloride. The conditions for both valuable metal recoveries were optimized.INTRODUCTIONSelective Catalytic Reduction (SCR) catalyst has become the most effective to reduce nitrogen oxide (NOx) emissions from stationary segments such as power plants and waste incinerations around the world due to the reinforcing regulatory trend and emerging environmental issues (Forzatti, 2001; Spivey, 2002; Li et al., 2011).Currently, the most widely used SCR catalyst is V2O5-WO3/TiO2 system due to its great catalytic properties (Li et al., 2011; Marshneva et al., 1995; Marbergeret al., 2015). In general, the composition of the SCR catalyst used in the stationary application is 0.5 to 1 wt% of V2O5and 7 to 10 wt% of WO3(Marberger et al., 2015; Chen &Yang, 1992, Vuurman et al., 1991; Alemany et al., 1991). Currently spent SCR catalysts are treated as waste and disposed of in landfills. This causes a lot of waste of secondary resources of vanadium and tungsten. In terms of industrial value of vanadium and tungsten (Gupta &Mukherjee, 1990; Moskalyk &Alfantazi, 2003) and reduction of pollutant emissions, it should not be disregarded for their recovery for their material recycling from spent SCR catalyst. However, investigations for recovery of metal values from spent SCR catalyst has been rarely carried out."

Jan 1, 2017

By I. S. Parrish

The Sullivan Mining Group has been exploring the mineral deposits of the Mount Pleasant area of southern New Brunswick since 1967. Sullivan geologists have logged over sixty miles of drill core, mapped over five miles of underground workings and studied numerous surface exposures. Several mineralized zones have been defined and two higher-grade porphyrytungsten bodies delineated. Within these bodies, wolframite occurs as disseminated specks and grains up to one-half inch in diameter. The host rock is a brecciated rhyolite porphyry that has intruded quartz-feldspar porphyry of Mississippian age . The host rock is itself intruded by an acid porphyry called transition rock and is underlain by a microgranite. The mineralized zones, host rock, transition rock and microgranite are all thought to be derived from the same magma, and to represent progressive fractions from that magma.

Jan 1, 1978

By Frank Wright

"The Icon Sullivan Joint Venture ore deposit was discovered in June, 1965 by Messrs. Paul Benard, Bob Galipeau and Mac Watson working under the direction of Mr. Andrew J. Troop, as employees of the Icon syndicate. The deposit is located on the Waconichici River as the south end of Baie du Poste of Lake Mistassini, approximately 45 miles north of Chibougamau. Property acquisition and Winkie drilling was followed by a diamond drilling program to evaluate the deposit. Stripping of the open pit area connnenced in the late fall of 1966 and the first test sample of ore was shipped to Chibougamau in December of that year.Regular ore shipments to the mill of Merrill Island Mining Corporation Limited for concentration commenced May 25, 1967. Production to December 31, 1970 amounts to 42,960,000 pounds of pay copper.The ore is chalcopyrite in white quartz dolomite, and it contains a very small amount of precious metals. The quartz dolomite assumes a flat to gently dipping attitude and is associated with a graphitic argillite contact zone on both hanging and footwall sides, in dolomitic limestone rocks. There is practically no other sulphide present in the ore.During the summer of 1969 a series of pre-concentration tests were completed and a Wemco heavy media sink float plant was installed in late 1969 and early 1970. This pre-concentrator eliminates at least one third of the ore mined in the form of barren quartz dolomite prior to ore shipment by truck to the concentrator in Chibougamau."

Jan 1, 1971

By J. E. Zajic, E. A. Sullivan, T. R. Jack

"The release of vanadium, iron, nickel and titanium from the cokes produced in the upgrading of Alberta oil sands bitumen has been assessed for simple chemical leaching processes. Flexicoker coke (Exxon Engineering and Research) has been found to be quite amenable to the recovery of vanadium as well as nickel, iron and some titanium by these techniques, whereas fluid coker coke (Syncrude) and delayed coker coke (Great Canadian Oil Sands) are relatively intractable under the mild conditions employed. The factors affecting the extent of vanadium release are discussed in terms of the surface area accessible, the wettability of the material, and the chemical and physical composition of the coke particles in each case.A novel biologically assisted heap leaching procedure for f1exicoker coke is also described, based on the growth of the chemolithotrophic bacteria, Thiobacillus thiooxidans A TCC 8085, on elemental sulphur added to the coke."

Jan 1, 1980

By G. Granata, C. Tokoro, T. Kato

"The goal of this study was to evaluate the effectiveness of mechanochemical activation by planetary milling as method to enhance the recovery of cerium from rare earth ores. For this purpose, a weathered ore was first ground by planetary milling and then leached by sulfuric acid. The influence of planetary milling was investigated by assisting the experiments with X-ray absorption fine structure (XAFS) in cerium LIII-edge and inductively coupled plasma spectrometry to measure the concentration of cerium dissolved by leaching. Results showed that, by increasing the grinding time, although the particle size of the specimen increased due to agglomeration, the recovery of cerium significantly increased. This finding clearly indicated that a smaller particle size actually hinders the recovery of cerium. In particular, XAFS analysis revealed that the longer the grinding time, the more tetravalent cerium could be converted into trivalent cerium and such conversion, also called mechanochemical reaction was beneficial to the recovery of cerium. Based on the obtained results, it was confirmed that approximately 70% of cerium could be recovered by mechanochemically activated leaching of rare earth ores.INTRODUCTION Rare earth elements (REEs) are a group of 17 chemically similar metallic elements comprising lanthanides, scandium and yttrium. Since REEs have various unique physical and/or chemical properties, they have become essential materials for advanced application (Adachi, 2015). REEs used in industry are usually supplied as rare earth minerals. In the last decades, flotation, gravity separation, magnetic separation and leaching have been widely applied to recovery of REEs from rare earth minerals like monazite (Archana, Rekha, Manis, Jitendra, & Jin, 2015). Among these operations, leaching has been widely studied in the recent years to improve the state of the art (Archana, Rekha, Manis, Jitendra, & Jin, 2015; Xiao, Feng, Huang, Huang, Chen, Liu, Wang, & Long, 2016; Farzaneh, Fereshteh, & Ahmad, 2017). Aiming to enhance recovery of REEs from rare earth minerals, a possible advancement of leaching technology could be the mechanochemically activation of the ore by high-intensity milling (Alorro, 2016). In the mechanochemical activation, an improvement of the leaching performances can be achieved through high-intensity milling operations which result into a dramatic decrease of the mineral particle size with a consequent improvement of the physical kinetics of leaching. Furthermore, the high mechanical energy provided to the sample during milling can determine the rupture of the crystal structure of the mineral, thereby transforming it into a more leachable form."

Jan 1, 2017

By R. Carrier

"There has been a continuous evolution with the use of pre-cast concrete elements in the construction of aluminum smelters. In 1990, Phase I of Alouette was built using cast-in-place concrete exclusively. Whereas, other AP 30 technology plants such as Hillside 2 in the mid-1990s used pre-cast concrete beams with cast-in-place floors. Mozal 2, in 2002, used pre-cast concrete beams with pre-cast partial-slab operating floors. Alouette Phase II went further. Not only were the potroom building beams and floors pre-cast, but the entire pot support system, insulating walls and basement jersey walls were pre-cast. Once the techniques for bending and welding the reinforcement bars and the design for attaching electrical insulating plates to the concrete was perfected, the challenge for the project remained only in the logistics of transporting the pieces to site and simple erection. The overall impact on the project was dramatic. Using prefabricated concrete not only allowed advancement of the schedule, but totally eliminated formwork, re-bar installation, and form removal activities along with the handling of all the materials involved with these activities. With the elimination of these labour and material-intensive portions of the job, exposure to work injuries was dramatically reduced. The most prevalent activity for lost time accidents is during the rough work associated with concrete formwork, placing concrete and form removal. Another area where prefabricated elements were successfully used on Alouette Phase II was for the insulating walls enclosing the pot area, known as the ""claustra walls"". Usually these walls are constructed in-situ using mortar and breeze block. Success was also achieved with prefabrication of the perimetric walls that are installed at the lower floor of the potroom. A big advantage of using prefabricated concrete in the electrolysis area is in assuring electrical isolation for the operating floors. Poured concrete requires a meticulous clean-up effort before commissioning to establish the electrically ""floating"" characteristics of the operating floors. Poured concrete results in ""wash"", stray wood,"

Jan 1, 2006

By F. Habashi

"The rare earths industry started in Austria in 1887 by Carl Auer von Welsbach (1858-1929) Professor of Chemistry at the University of Vienna. The process was based on monazite sand transported from Brazil as shipping ballast free of charge. This made possible producing thorium, cerium, and other rare earths at a low cost, thus permitting the growth of the industry. However, once the Brazilian authorities realized the strategic importance of the sand, shipping was stopped. Brazil then started its own processing of the sand in 1949. The background for Auer’s work, the role of Robert Bunsen in Heidelberg, and the invention of the spectroscope will be presented. INTRODUCTIONHeidelberg on the Neckar (Figure 1) was the meeting place for chemistry students from all over Europe in the nineteenth century. Her university founded in 1386 had already a famous professor of chemistry and medecine in the Faculty of Medicine by the name Leopold Gmelin whose three - volume Handbuch der theoretischen Chemie appeared in 1817-1819, that became later a multi-volume monumental work. As successor to Gmelin came Robert Bunsen (Figure 2) in 1852 who made this university town the Mecca of chemistry students. One of his students, the English Henry Roscoe (1833-1915) who became later a distinguished professor in Manchester, described him as follows: ""As an investigator he was great, as a teacher he was greater, as a man and a friend he was greatest""."

Jan 1, 2012

By Q. Dong, S. A. Nightingale

An investigation has been carried out to assess the effects of an applied voltage on the dissolution rate of MgO refractory in a steelmaking like slag. In this study corrosion results obtained from dip tests using a dense direct bonded MgO refractory in a CaO-SiO2-Fe2O3-FeO-MgO slag are presented. These results demonstrate that the application of a voltage across a dense MgO refractory-slag interface can change the rate of refractory dissolution. For the slag composition used and the voltage range tested, it was found that a maximum corrosion rate was obtained at a voltage setting of -0.45V. The results of this investigation have been explained in terms of voltage affects on Marangoni (interfacial tension induced) stirring and its effect on the MgO dissolution reaction that is at least partly controlled by mass transfer in the slag.

Jan 1, 2004