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In the last five years, new iron ore pellet plants have been built with significantly reduced air pollution levels compared to the older generation of plants. European and American pollution controls are more stringent that in China and Brazil. The recent American plants have successfully employed circulating fluidized beds for sulfur control, baghouses for particulate control, activated carbon injection for mercury and a new design of specialized low-NOx burners.

Jan 1, 2015

By A. LA. Salama, D. B. Hyma

"The Western Research Centre (WRC) of CANMET located in Devon, Alberta, is a modern research facility offering services ranging from fundamental research to pilot plant investigations. Recently, a 0. 76 metre diameter by 7.9 metre high Flotaire column flotation cell was installed as a demonstration unit for Canadian coal producers. Because the column cell is intended to be used for research, development and demonstration, WRC recognized that additional sensing equipment and improved process control would be required to generate good data for subsequent column scale-up and engineering design.A low cost, personal computer based control system was, therefore, designed and installed. This paper describes the stepwise procedure in developing the control strategies, selection of system software and hardware, and installation and configuration of the system.Preliminary performance data on a western Canadian coal sample are also presented. Future testwork is planned on additional coal samples to expand upon existing database."

Jan 1, 1993

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 S. Kelebek, U. Demir, T. C. H. Richards, E. Koss

"Laboratory-scale tests were carried out to investigate the response of a high-grade (~143 g/tonne) well-liberated gold ore to flotation using two collector types. Octyl and amyl xanthates, representing conventional types of collectors, were tested against an n-octanoic and hexanoic acids under moderate and high redox potential conditions. The latter was based upon a suggestion in literature that monocarboxylic acids are able to adsorb onto the surface of gold at redox potentials near 600 mV (SCE). This investigation did not demonstrate that these carboxylic acids could function as collectors for gold in real ores. In fact, they appear to have slightly depressed gold. However, the results demonstrated that octyl and amyl xanthates acted as highly effective gold collectors for this ore and that an increase in the collector dosage led to an increase in recovery for all mean particle sizes. In some tests, gold recoveries of around 95% were attainable in concentrates with grades around 6 kg/tonne, indicating that xanthate flotation remains a viable means of concentrating gold even at coarse grain sizes. Various aspects of the process such as grade-recovery performance and recovery by size are discussed.INTRODUCTION Three methods are used for the recovery of gold in mineral processing, either alone or in combination: gravity concentration, cyanidation and flotation. Gold occurs as a by-product in some ores together with platinum group metals and as the primary metal in other ores in the form of native gold and electrum, which are alloys of gold, silver and minor amounts of copper. Flotation is a viable method for recovering liberated gold where the gold is visible under an optical microscope (greater than 1 µm in size) and where the attachment of gold grains is not prevented due to bubble loading by competing minerals. It is generally known that grains finer than 150 µm in size will float with most collectors."

Jan 1, 2017

By T. S. Smith, C. C. Rennie

"THE LEAD-ZINC and tungsten mines of Canadian Exploration Ltd are on Iron Mountain, 8 miles south of Salmo, B.C., in the Nelson mining division. Relative location of the mines is shown on the general plan.First recorded lead production was in 1908 from surface outcrops. Small amounts of high lead ore were mined intermittently until 1926. No major lead-zinc production occurred until 1949 when outcroppings on the south side of the mountain were mined and diamond drilling began to prove the existence of a large replacement orebody. Lead-zinc ore has been mined continuously from the Jersey orebodies since March 1949, with monthly tonnage as high as 50,000 tons per month, but currently averaging 30,000 tons per month.Schee1ite-bearing tungsten ore was found in 1942 by H. Lakes in an old adit and open cuts at the north end of the Emerald tungsten orebody. The Emerald tungsten mine was developed by the Federal Government as a Wartime Metals project and operated for eight weeks in the fall of 1943, when the poor demand for tungsten closed the mine. Canadian Exploration Ltd. purchased the mine in 1947 and mined in excess of 100,000 tons in 1947-48 until the demand for tungsten dropped again and interest was centred on lead-zinc. The Federal Government repurchased and reopened the Emerald Mine in 195 L and built a new concentrator. The mine and mill were sold back to Canadian Exploration Ltd. in 1952.Regional Geology and IntrusivesThe host rock for both the lead-zinc and tungsten mineralization is the Laib formation of Lower Cambrian age, which consists of 400 feet of crystalline limestone underlain by beds of argillite, and argillaceous limestone locally altered to ""skarn"" or ""tactite"". The Laib limestone is overlain by black argillite and underlain by the Reno quartzite of Pre- cambrian age. Repetition of folded beds has allowed the interpretation of the large isoclinal fold which repeats the limestone (see general cross-section). Dolomitization and the associated lead-zinc ore have been found only in the right-side-up limestone and are not known in the overturned limestone.Two elongated stocks of granite cut the sediments. The Emerald stock outcrops along the east side of the Emerald tungsten mine and again west of the Jersey workings, while the Dodger stock outcrops only at the north end of the Iron Mountain. The shape and attitude of these bodies are believed to have been governed partly by pre-granite faulting and partly by pre-granite folding of the sediments. Although some forceful intrusion may have occurred the detailed granite surface indicates a gentle stoping emplacement."

Jan 1, 1949

By Xuanxue Mo, Zengqian Hou

"Abstract -Yidun Island Arc in Sanjiang Region is one of the important Kuroko-type volcano­ genic massive sulfide deposits (VMS) districts in southwestern China. Tectonically, the region is situated in the eastern portion of the Tethys orogenic belt, and is a late Triassic extensional island-arc. The island-arc underwent earlier arc construction, intra-arc rifting, later arc construction and back­ arc spreading during its evolution and formed a complete trench-arc-basin system, i.e., the Ganzi­ Litang suture zone, forearc basin, outer arc, intra-arc rifting zone, inner arc and back-arc basin from east to west across the island-arc.Kuroko-type VMS deposits and occurrences discovered so far are limited to within the intra-arc rifting zone of the Yidun Island Arc and tend to occur in groups or clusters distributed in separate fault­ bound basins; e.g., Zengke, Gacun and Xiangcheng basins, in which submarine volcanic rocks, especially bimodal volcanic suites, were extensively developed. The VMS deposits formed in the waning stages of volcanic eruption in the late Triassic and are hosted in the uppermost section of acidic volcanic rocks (rhyolitic-dacitic) within a bimodal suite. The orebodies are associated with these host rocks: rhyolitic-dacitic pyroclastic rocks and exhalites and chemical sedimentary rocks.Ali VMS deposits in Sanjiang are of the Zn-Pb-Cu type. The architecture of the deposits is two­fold, consisting of concordant lenses and layers of massive sulfides and an underlying discordant stockwork. Ali deposits show metal zoning. The hydrothermal alteration related to mineralization is strong and asyrnmetrical, and is found dominantly within the stockwork zone and host rocks surrounding the ores. There are two alteration patterns: (1) chloritization - sericitization - silicification from outer sides to core of the alteration pipe; and (2) silicification + sericitization - silicification + carbonate from the lower to upper part of the alteration pipe_The mineralization temperatures of ore-forming fluids vary in the range 200°C to 335°C. Thermal evolution of the fluids displays temperature profiles that first increase and then decrease with progression of mineralization processes. The majority of black-ore minerais (Groups I and II) formed during intensifying stages of hydrothermal activity, and the majority of serni-yellow-ore minerals (Group III) formed during a thermal maximum . There followed the formation of fine-grained black-ore minerals (Group IV), which interacted with barite layers during decreasing temperature phases.Oxygen and hydrogen isotope studies show that the sources of ore-forming fluids for the Kuroko­ type VMS deposits are two-fold: seawater and magmatic hydrothermal solutions, represented by the Kuroko deposits in Japan and Kuroko-type VMS deposits in Sanjiang, respectively. In the latter case the hydrothermal solutions reacted with host rocks and mixed with cold seawater percolating downward, and circulated through volcanic rocks resulting in development of alteration zones and formation of ore minerals in Kuroko-type VMS deposits."

Jan 1, 1993

By E. M. Cameron

Reconnaissance radiometric and geochemical data have been obtained for an area on the western shore of Wollaston Lake that includes the Rabbit Lake uranium deposit. The study area is extensively drift cover ed. The geochemical data were obtained by analysis of center-lake sediments and surface waters for a variety of elements and other constituents. The airborne radiometric data comprise measurements of eU, eTh and K obtained with a .50,000-cc NaI (Tl) detector at a mean terrain clearance of 120 m and 5-km flight-line spacing. Uranium in lake sediments and uranium in waters are the most effective geochemical indicators of uranium mineralization; the other elements measured are not notably anomalous. A sample site density of one per 1 8 km 2 is more than adequate for identification of the mineralized area. Because many water samples contain close to or below the current analytical detection limit of 0.05 ppb U, the use of sediments is generally favoured. for broad-scale reconnaissance in the region. Uranium in these lake sediments appears to be little influenced by variations in the organic or iron and manganese content. The most effective radiometric indicator of the mineralization is the eU/eTh ratio. This parameter is less influenced by environmental variation on the ground beneath the flight line than eU alone . The eTh/K ratio is anomalous under the Athabasca Formation unconformity where, in places, the uranium mineralization is localized.

Jan 1, 1977

By H. A. Hamza

An experimental study of the settling characteristics of a washery effluent originating as tailings from a froth flotation circuit was undertaken by using a systematic approach to select the most appropriate flocculant(s) under predetermined conditions. Selection and evaluation procedures which greatly reduce the effort required to select flocculants are described. The results show that, although different flocculants display superiority at different ranges of dosage. Separan MG 700 (Dow) is the most suitable on absolute economic grounds. Flocculant evaluation is based on a Cost Performance Index (CPI) which expresses the cost of flocculant (¢/ton) required to produce a unit settling rate (in./hr). From experiments carried out with a number of flocculant aid and flocculant combinations, it was concluded that the use of flocculant aids can be economically justified only if the settling rates required are higher than those obtainable at the optimum flocculant dosage. Otherwise, the value of the flocculant aid appears to be limited largely to the reduction of supernatant turbidity.

Jan 1, 1979

By Philippe Caudal

This paper presents a case study in which a slope failure was observed on the west wall of the LAB Chrysotile mine in the vicinity of the main ramp in January 2010. Airborne LiDAR results were used to evaluate slope geometry before and after the failure occurred. Back analysis of the failure was performed to assess rock mass properties at the slope scale using various numerical techniques: limit equilibrium, finite elements and fracture networks. The various approaches correlated well with field observations.

Aug 1, 2013

By Brian Hart, Zhe Chen, Liuyin Xia, Mana Pourdasht, Stamen Dimov

"Gold losses related to carbonaceous matter (CM) during processing are a significant problem in the gold processing industry. Inherent CM in gold ores can behave similarly to activated carbon in its ability to adsorb gold cyanide. This phenomenon is termed preg-robbing as the surface adsorbed gold cannot, for the most part, be recovered. Research has identified that gold adsorption by inherent CM is linked to the specific surface area, pore structure, degree of C disorder and surface functional groups. One of the strategies to inhibit CM preg-robbing prior to leaching is a chemical oxidation; a process linked to modification of the surface functionality. In this study, the variability in gold cyanide adsorption due to oxidation with different reagents has been investigated. Variability in gold cyanide adsorption by CM is examined in relation to structural and surface modifications using TOF-SIMS, XPS and Raman spectroscopy.INTRODUCTION A major obstacle for effective gold recovery during carbon in leach (CIL) or carbon in pulp (CIP) processes carbonaceous gold ores is the presence of carbonaceous matter (c-matter) which has the ability to adsorb, or preg-rob gold from the cyanide leach solution. It can be responsible for poor recoveries as the carbonaceous materials (CMs) within the ore competes with activated carbon used during the leaching and adsorption phase of processing (Cay, 2014). Preg-robbing capacity can vary significantly with mild preg-robbing ores showing absorption capacities of less than 1 g Au/t ore, while severe preg-robbing ores may have CM with the capacity to preg-rob more than 500 g Au/t ore (Dunne, 2007). Research by a number of groups have shown that the degree of C disorder has some influence on the ability of the carbonaceous material to adsorb Au(CN)2- (Miller et al, 2005, Helm et al, 2009, Hart et al, 2010). It is also apparent the adsorption characteristics of carbonaceous material is affected by changes in surface chemistry (Dimov, 2016). Various treatment including; flotation to remove the carbonaceous material (Wills, 2010), addition of surface blinding agents (for example kerosene) to passivate or blanket the carbon surfaces (Dimov, 2016), addition of strong adsorbents (eg. activated carbon or resin) to compete with the carbonaceous material and passivation or surface coating by oxidation (pressure, roasting, chlorination and biological oxidation), have been employed prior to leaching in an attempt to minimize the gold losses (Dunne, 2013)."

Jan 1, 2017

By S. R. Steinacker, H. Schnideritsch, J. Antrekowitsch

Primary copper industry flue dust plays an increasingly important role in the creation of matte and slag. From a thermodynamic point of view, the chemically formed section of fine particles play a techno-logically interesting role in comparison to the mechanical carry-over. Here, the volatilization and the sub-sequent condensation in the off gas system lead to a characteristic distribution of the contained elements which are represented by various compounds of desired metals like zinc and lead. On the contrary, certain undesired components such as arsenic, bismuth and cadmium accumulate within the product as well. This paper describes existing models and theories concerning the formation of flue dust in the copper smelting process and presents a thorough investigation of the physico-chemical fundamentals by verifying assump-tions with thermodynamic calculations. By fully understanding the formation patterns at different stages and temperatures within the process, better knowledge for flue dust in the first step of the pyrometallurgi-cal copper smelting can be obtained - hence leading to new ideas and incentives for the following stages in the copper production cycle.

Jan 1, 2015

By W. E. Roscoe

"Mineral exploration properties are those on which an economically viable mineral deposit has not yet been discovered. Such properties are bought, sold, optioned and joint ventured on the basis of their perceived potential for the existence and discovery of a viable mineral deposit. The intrinsic value of an exploration property is therefore based on the exploration potential. One measure of the exploration potential is the amount that can be justified to spend on exploration for a viable deposit.The appraised value method uses a cost approach to value exploration properties. It is based on the premise that an exploration property is worth the meaningful past exploration expenditures plus warranted future costs to test remaining exploration potential. Results of past exploration work are analyzed in order to retain only those past expenditures that are productive in terms of identifying remaining potential. Warranted future costs comprise a reasonable exploration budget to test that potential."

Jan 1, 2002

"3.1. IntroductionAmong the six platinum-group elements (POE), four have identical cubic symmetry, two identical hexagonal symmetry (Table 3.1). Despite crystallographic differences, there is a clear relationship expressed in the chemistries of the POE: they tend to be mutually soluble in one another and can frequently substitute for one another in compounds with other elements. This chapter consolidates the data on phase relations of the POE and the compounds they form with elements selected for their known or potentially important mineralogical significance- As, Bi, Cu, Fe, Hg, In, Ni, Pb, S, Sb, Se, Sn and Te-together with selected data for the occurrence of POE in certain elements such as Au and Ag, and compounds such as FeS. Resources used to compile the data are those available from the chemical, mineralogical and metallurgical literature. First each element is discussed, with composition limits of solid solutions drawn from binary phase diagrams. Single element data are followed by a discussion of the relevant binary systems and a tabulation of data for binary compounds found in those systems (Table 3.2). Tables and diagrams for the ternary and quaternary systems for which information is available follow, and finally the very limited information on the solubility of POE in mineralogically important elements and compounds is presented.The chemical, mineralogical and metallurgical literature on the unary and binary systems is extensive and widely scattered in many languages and publications; fortunately, most of the data needed to compile this chapter can be found in reliable compendia. The most useful and most recent of these works is by Moffatt (1979), because it provides a ready index to all material relating to binary systems listed in previous compendia; furthermore, the Moffatt compendium will reportably be kept up to date by annual supplements."

Jan 1, 1979

By H. P. Pew

THE Pembina oil field is in west-central Alberta, about 88 miles west-southwest of Edmonton. The field, about 35 miles long by T HE Pembina oil field is in west-central Alberta, about 88 miles west-southwest of Edmonton. The field, about 35 miles long by 85 miles wide, is the largest in Canada in areal extent, in the amount of oil in place and in the current producing rate. The discovery well was completed in the middle of 1953. The field has grown until its present area is 369,820 acres. There are 74 working interest owners in the field. Early in the producing history of the Pembina field a committee of operators was formed on a permanent basis. The Pembina Operators' Committee has established a permanent staff, which compiles and distributes pertinent field information on a regular basis to all participants. The Alberta Oil and Gas Conservation Board has dealt with field-wide problems primarily through this committee. Expansion of the field was rapid as shown by the number of wells completed -from 135

Jan 1, 1961

A semi-automatic device has been constructed that can be used to check the solution strength of cyanide solutions. It consists of a wheel on which a gold-foil-bearing glass slide is mounted. The wheel moves the gold foil through the solution under test and intercepts a light beam. As the gold foil is attacked by the cyanide solution its light absorption diminishes. The successive in-crease in transmitted light intensity is recorded and gives a measure of the gold dissolution rate. Curves have been obtained to show the effect of cyanide concentration and oxygen content on dissolution rates. Details are presented of the construction of the unit, and some practical operating procedures are outlined. 0 NE of the important, although often neglected, factors in the extraction of gold by cyanidation is the actual dissolving strength of the cyanide solution. This depends in a

Jan 1, 1964

By T. Crivits

"Freeze lining technologies are used industrially to protect the integrity of furnace walls in pyrometallurgical reactors. This is achieved by solidifying a protective layer of slag on the inner furnace wall. In the current study, laboratory experiments have been undertaken to produce freeze linings in ‘Cu2232 O’-‘FeO’-MgO-SiO slags under controlled conditions using an air-cooled probe technique. Whilst most thermal models of freeze linings have assumed the freeze lining-bath interface to be at the liquidus temperature of the bulk bath and to be planar in geometry, the current research has demonstrated that this is not the case. Experiments undertaken using this high-temperature slag system have shown the interface at steady state conditions to be at subliquidus temperatures. The solid phases present at the interface do not include the primary phase and the interface is non-planar. The study indicates the need for improved understanding of the fundamentals of freeze lining formation, and of the influence of system properties and process parameters"

Jan 1, 2015

By A. C. Stevenson

"The most common theory is that, since thyristors, diodes, and insulated gate bipolar transistors (IGBTs) are “solid state” they will live forever. This is not so. They have wear-out mechanisms (e.g. insulation) and other mechanical parts such as motor bearings. These wear-out phenomena can be easily calculated. In this paper we will look at some of the failures and the failure rate of thyristors in power converters to see what affects them and to see what improvements can be made. If converter failures do occur, some simple forensic engineering steps will show if this is the root cause of the problem.IntroductionLook at the general failure rate curve for thyristors, diodes, gate turn off devices (GTOs) and IGBTs shown in Figure 1. We see that there is an initial high failure rate due to manufacturing defects, application problems, and drive start-up stresses that lasts for a few weeks. This is followed by a long period of (hopefully) several years with a relatively low but very slowly rising failure rate. At the end of this period, the devices start to wear out and the failure rate suddenly starts to increase rapidly over a few months. This signals the end of life for the devices in the system. We will start by looking at this end of life area."

Jan 1, 2000

By J. C. Underwood

"The wear performance of grinding balls under conditions of impact and abrasion is affected by their chemical composition and structure. The selection of appropriate analyses and heat treatments that will provide both abrasion and impact resistance takes into account the effects of certain elements on structure and harden-ability, as well as the over-all effect of composition and hardness penetration on the residual stress pattern developed through heat treatment. Direct quenching from forging temperatures substantially increases hardenability over that obtained in reheat-quench practices, and can be done without undue risk of damage to the ball provided that the harden-ability bears the correct relationship to ball diameter.Average volumetric hardness and percent hardened volume are convenient parameters for quantitatively expressing the response to heat treatment and indicating anticipated wear properties. A number of factors which can lead to reduced wear life as a result of material or processing problems are reviewed and illustrated."

Jan 1, 1959

By J. -F. Lepage, M. A. Tomlinson, K. K. Murray

"The Éléonore mine, located in the James Bay region of Northern Quebec, generates a gold bearing flotation concentrate rich in pyrrhotite. Direct leaching of the finely ground concentrate results in high cyanide consumptions and poor recoveries, so effective pre-treatment to passivate the pyrrhotite is required before leaching. Following a number of process upsets at the mine, test work was performed to better understand the requirements for passivation so a more effective operational strategy could be implemented. This paper outlines the testing and implementation of the new strategy at Éléonore.ÉLÉONORE CONCENTRATOR The Éléonore mine is located 800 km north of Montreal, in the James Bay Region of Quebec, Canada. The ore, containing gold disseminated in sulfide minerals and free fine gold in silicate gangue, is crushed in a two-stage crusher plant before being ground in a single 9,000 kW ball mill. The ball mill is in closed circuit, with about 25% of the cyclone underflow passing through a gravity plant with two, 48” Knelson concentrators. Gold recovery in the gravity circuit varies between 15 and 20%, with gravity concentrate leached daily in an Acacia intensive leach reactor. Cyclone overflow, at a target P80 of 65 microns, flows to the flotation plant where the gold bearing sulfide minerals, mainly pyrrhotite and arsenopyrite, are recovered to concentrate with a mass pull of about 5%. The flotation concentrate, typically containing between 80 and 120 g/t of gold, is thickened and finely ground using a 1500 kW Isa Mill. The finely ground concentrate is diluted, to generate a slurry with about 32% solids by weight, before feeding the leach plant. Initially the concentrate slurry is pre-treated with oxygen and lead nitrate, to passivate the sulphide minerals before cyanide is added for gold dissolution. Gold is recovered from the leached slurry using carbon-in-pulp (CIP). The flotation tailings are also thickened and gold is recovered in a dedicated leach-CIP plant."

Jan 1, 2017

By D. M. Maijer, S. L. Cockcroft, S. Modak, A. B. Phillion

"A comparison between hydrogen-diffusion-based micro-porosity formation and growth behaviour of two important aluminium foundry alloys, B206 (Al-Cu) and A356 (Al-Si-Mg) is presented in this paper. Specifically, the predicted pore size and pore fraction distribution of these two alloys resulting from directional solidification and identical hydrogen concentration are investigated numerically based on a model proposed by Yao et al. (2011. Met. & Mat. Tran. A. 42A, 4137–4148). This model takes into consideration the initial hydrogen content in the melt, the cooling rate, the partitioning of hydrogen between the solid and liquid phases, and the evolution in solid fraction with temperature. Due to different alloy chemistries, the activity of hydrogen in B206 and A356 are quite different, as are the solidification range and the resulting solidification microstructure. Being a primary alloy, B206 has dendritic microstructure and solidifies over nearly 135°C (505–641°C), whereas A356 contains fifty percent eutectic microstructure, and solidifies over 80°C (533–613°C). This allows a very different behaviour of micropores i.e. the effective pore radius in B206 is quite a bit lower as compared to A356, as is the pore number density. The evolution of local hydrogen concentration in liquid metal is analysed and compared for both the alloys.INTRODUCTION Over the past decades, the demand for materials with enhanced strength-to-weight ratios has significantly increased in the aerospace and automobile industries in order to improved fuel efficiency. For many automotive components, particularly shape castings, the trend is towards replacing ferrous alloys with aluminium alloys. The increase in the use of Al is primarily due to its low density, about one-third that of steel, and its relatively good strength that allows for weight reduction without reducing performance. Presently, Al-Si based alloys (e.g. A356) are the most prevalent due to their good mechanical performance in strength-to-weight ratio and excellent castability (Atwood et.al., 2000). However, superior mechanical properties can be achieved using Al-Cu alloys. For example, the alloy B206 offers a higher strength while retaining excellent ductility (Poirier et.al., 1987)."

Jan 1, 2017