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By D. L. Cluff

Ventilation Air Methane (VAM) is a high volume low concentration methane source. The capture or use of methane from VAM is challenging, which results in the routine discharge of methane into the atmosphere. Mitigating VAM has the benefits of providing an energy source and reducing the atmospheric Greenhouse Gas (GHG) burden. The GHG radiative forcing effect of methane is 17?23 times as potent as carbon dioxide on a 100-year time horizon. Thus, any reduction in atmospheric methane would be beneficial. The calorific value of methane is 55.5 MJ/Kg; therefore, a 100 m3/s flow with VAM concentrations from 0.1?1% can provide 3.8?38 MW of exploitable power. Strategies to mitigate VAM such as: Thermal Flow Reverse Reactors (TFRR), Catalytic Flow Reverse Reactors (CFRR), Lean Burn and Catalytic Gas Turbines, Biothermica Vamox®, Megtec VOCSIDIZER©, and Vamcat? are briefly reviewed. The review of VAM mitigation technologies reveals disadvantages such as the need to maintain a minimum internal heat capable of oxidizing the methane. This requirement uses all of the available methane up to the point of reaction sustainability and up to half at the highest methane concentration in VAM. Some systems may introduce a pressure drop to the ventilation system, which would impinge on the existing ventilation system design. These impediments necessitate the development of a more amenable technology. In the proposed system, gas turbines (GT), coupled to a combustion chamber with an external fuel supply, assist the combustion of the VAM. The combustion-chamber coupled system provides electricity, while the heat contained in the GT exhaust gases increases the temperature of the VAM, encouraging the development of a flame inside a combustion chamber. The flow from the combustion chamber streams through a primary air/fluid heat exchanger capable of producing steam of a high enough quality to generate electricity using conventional steam turbines. The residual heat after primary extraction, directed through other equipment, provides additional heat based products such as industrial scale dry air, chilling by an absorption chiller or hot water. The overall design of the system is scalable for low to high VAM flows or variations in concentrations and is capable of providing the company or community with heating, chilling, hot water, electricity or motive force as needed by the particular site or community. The Multi-generation system uses heat from three sources to provide clean efficient energy while mitigating the atmospheric emissions of methane. These sources are heat from the GT, often considered waste heat, heat from fuel injected into the igniters and heat from the VAM. The opportunity to collect carbon credits may improve the economics. In order to design a system with this capacity, a detailed analysis of the combustion characteristics of three separate flows is required. VAM is the main airflow, having the highest volumetric effect, while the GT exhaust and the additional fuel added to the hot exhaust flow of the gas turbine are lower flows, but have a higher velocity and temperature. The aim of the modeling undertaken in this work is to establish the combustion dynamics, degree of pre-heating required and the geometry essential to the design of combustion based VAM mitigation multi-generation systems.

Aug 1, 2013

By Jon A. Carlson, W. Scott Williams

The EKATI"" Diamond Mine commenced operation in October 1998. It is operated by BHP Diamonds Inc., which is a part of the Non-Ferrous and Industrial Materials Division of BHP Minerals, a business unit of BHP Company Ltd. of Melbourne, Australia. The EKATI"" Diamond Mine is a joint venture of BHP Diamonds Inc. (51%), Dia Met Minerals Ltd. (29%), Charles E. Fipke (10%) and Dr. Stewart L. Blusson (10%). In December 1993, an office was opened in Yellowknife, Northwest Territories specifically for the then Northwest Territories Diamonds Project (EKATI"" Diamond Mine) development. EKATI"" Diamond Mine is located 300 kilometres northeast of Yellowknife and 200 kilometres south of the Arctic Circle in the Northwest Territories of Canada (Figure 1 ). The site is located in a remote tundra area of continuous permafrost, north of the tree line, which is part of the Canadian Shield. Wekweti (Snare Lake), a Dogrib community approximately 180 kilometres southwest of the project, is the closest neighbour. The mining area and facilities lie within the 10 960 hectares land leases held by the joint venture. The total claim block (core zone and buffer zone joint ventures) covers 344 000 hectares. To date, more than one hundred kimberlite pipes have been identified within the claims. Five of these provide the basis for the present mine plan. Total capital investment in the project is over C$700 million. At full production employment will be about 600, including employees and long-term contractors, with over 33% being Aboriginal from the Northwest Territories.

Jan 1, 2001

By J. W. Kramers, R. A. S. Brown

"Samples from seven test wells distributed throughout the surface-mineable area of the Athabasca Oil Sands have been evaluated to determine the amounts of heavy minerals present and the titanium and zirconium contents. The samples were treated to yield the size distribution of the titanium and zirconium minerals as well as their spatial distribution. The study has shown that heavy minerals are found throughout the surface-mineable area; concentrations range from 0.24 to 2.29 per cent (by weight), with a mean of 1.02 per cent. Titanium and zirconium contents vary throughout the area, and are found preferentially in the finer size fractions. •on the basis of preliminary calculations, the tailings streams from an oil sands plant would provide sufficient feed for a large-scale titanium pigment plant, and the tailings from one plant would provide sufficient zircon feed to satisfy Canadian demand for. metallic zirconium. Variability of the heavy mineral content and composition is such that the heavy mineral potential must be evaluated in detail for each mine site."

Jan 1, 1976

By Tao Long

Recently, the great amount of funds has been invested in the reconstruction of damaged infrastructure and house of subsidence area of coal mine and mine reclamation. This is a benevolent and popular work, which is highly praised. However, because of complicated collapse area problems in China, especially the less integrated control research in the collapse area of metal mine, and the technological weakness, how to effectively control the subsidence area, restore landscape and ecological environment, and utilize the abandoned mine land, are major issue related to the mining area of sustainable development. The research situation about the formation of metal mine collapse area at home and abroad is reviewed, and then the effect of the collapse area on the mine safety and ecological environment, the existing technical problems and development direction are analyzed. Lastly, the technical measures of the collapse area control and cooperative underground mining is put forward.

Oct 1, 2010

"The outlook for Eastern Canada is decreasing coal production over the next few years; however, a reappraisal of the long-term requirements and increased prices of coal could lead to a revitalizing of the industry. The market for Western coal is expanding and is expected to exceed 50 million tons per year in the metallurgical and thermal power fields. Western coal reserves are currently estimated at 119 billion tons. Technical developments in Eastern Canada include a shearer and gate-end support system to mechanically cut the stall and brushing at the tail-end of a longwall. In Western Canada, the most modern equipment is used in mining, beneficiating and shipping coal. Results to date on the underground hydraulic experiments exceed expectations. The importance of reclamation is recognized and plans have been made to restore and re-vegetate disturbed areas and mine dumps. In Eastern Canada, experiments were started to determine the feasibility of coal reclamation from mine dumps, including one dump that is on fire. The Mining Research Centre, Mines Branch, continued to conduct research work oriented toward solving Canadian mining problems The Western office of the Centre, opened in 1970, was set up primarily to study problems associated with a resurgent coal industry."

Jan 1, 1971

By M. Nagamori, A. J. Plumpton

"Commercial HCl-leaching of magnesite and serpentine yields highly concentrated aqueous solutions containing 25 mass % to 33 mass % MgCl2. The partial molar enthalpies and heat capacities, the ionic activities of Mg2+ and Cl–, and the Raoultian activity of H2O have been assessed for the concentrated MgCl2-H2O solutions at temperatures of 348 to 373 K. These thermodynamic data are used to calculate the pH of aqueous MgCl2 solutions saturated with a Mg-bearing mineral such as magnesite, serpentine, brucite, forsterite, enstatite or talc. On the basis of these thermodynamic data, technico-economic aspects are discussed as to neutralization with pulverized MgCO3, water evaporation from the MgCl2 solutions, and ore composition including such minor constituents as CaCO3, FeCO3 and Fe3O4. IntroductionA major magnesium electrolytic reduction plant operates in Quebec, where another will begin its production in the year 2000. One uses imported magnesite ore as raw material, while the other will utilize local asbestos tailings (serpentine). Both processes produce a concentrated salt solution of 25 mass % to 33 mass % MgCl2 by leaching the ore with concentrated hydrochloric acid. Thus, the two processes differ mainly in the HCl-leach and related operations. After the HCl-leach of the ore, the serpentine process yields about 25 times more wet cake to filter and wash than the magnesite counterpart. A comparative cost-engineering study with respect to slurry filtration and cake washing has been published elsewhere (Blackburn and Nagamori, 1994). By contrast, the present study considers the thermodynamics and technicoeconomics of the HCl-leach itself for both ores."

Jan 1, 1999

"In response to needs created by intensive exploration and accelerating expansion of coal mining in the Western provinces, Canadian R & D on coal is progressively widening its scope. Principal interests continue to lie in coal geology, preparation and processing, carbonization, combustion and transportation, but much active work is also in progress with respect to mine environments, mined-land reclamation, and environmental consequences of coal mining, processing and use. Long-range 'basic' research, which characterized much of the R & D pattern in the fifties and early sixties and which was often no more than an attempt to prevent total extinction of a dying industry, has been somewhat de-emphasized, except insofar as it relates to 'safe' coal storage and to coal-based carbons (which are beginning to command attention as pollution control media).In this review, recent exploration, mine development and new preparation facilities are noted, and current R & D in transportation, processing, handling, carbonization and combustion is summarized. Reference is also made to investigations bearing on non-fuel uses of coal (notably as source-materials for carbons and agrobiological products)."

Jan 1, 1970

By G. H. Gale, M. A. F. Fedikow, L. B. Dabek

Rare earth element (REE) data are reported for ores, sul?de-bearing rocks and host rocks from massive sul?de deposits and barren sul?de facies iron formations in Proterozoic volcanic rocks of the Flin Flon-Snow Lake area, Manitoba. Some of the rare earth elements (e.g., Eu), are selectively leached in zones of intense alteration and redeposited together with the sul?des and silicatesin the uppermost parts of the alteration zones and at the rock-water interface. Chondrite normalized REE pro?les of layered sul?de ores and exhalites proximal to the deposits typically have positive europium anomalies and are enriched in light REE. In contrast, barren sul?de facies iron formations exhibit negative or ‘normal’ Eu pro?les. REE data are useful to explorationists in determining the presence of ‘off-hole’ metal-bearing sul?de zones, in distinguishing metal-poor sul?dic layers related to ‘economic’ hydrothermal activity from barren sul?de facies iron formation and in some instances as a means of establishing ‘ore-equivalent’ strata.

Jan 1, 1997

By G. H. Gale, M. A. F. Fedikow, L. B. Dabek

Abstract-Rare earth element (REE) data are reported for ores, sulfide-bearing rocks and host rocks from massive sulfide deposits and barren sulfide facies iron formations in Proterozoic volcanic rocks of the Flin Flon-Snow Lake area, Manitoba. Some of the rare earth elements (e.g., Eu), are selectively leached in zones of intense alteration and redeposited together with the sulfides and silicates in the uppermost parts of the alteration zones and at the rock-water interface. Chondrite normalized REE profiles of layered sulfide ores and exhalites proximal to the deposits typically have positive europium anomalies and are enriched in light REE. In contrast, barren sulfide facies iron formations exhibit negative or ‘normal’ Eu profiles. REE data are useful to explorationists in determining the presence of ‘off-hole’ metal-bearing sulfide zones, in distinguishing metal-poor sulfidic layers related to ‘economic’ hydrothermal activity from barren sulfide facies iron formation and in some instances as a means of establishing ‘ore-equivalent’ strata.

Jan 1, 1997

By Michel L. Bilodeau, Brian W. Mackenzie, Dallas W. Davis

"The paper formulates an evaluation procedure for examining the effects of location on the economics of developing mineral deposits. This methodology is applied to assess locational aspects of Nova Scotia's competitive position f or mine development relative to other Canadian regions and provinces. The appraisal concerns two representative mine development opportunities, a medium-size open-pit tungsten deposit, and a small underground gold deposit. The influence of regional economic conditions is initially assessed. Then, the consequences of taxation are isolated. Finally, the combined impact of regional and taxation conditions is examined. SettingThe economic potential of mining may be assessed in a number of ways. One approach, increasingly used for both corporate planning and government policy purposes, is to evaluate the competitive position of an actual or potential mineral producer in the international marketplace relative to other suppliers.Such examinations of competitive position vary from cost league comparisons of breakeven costs for operating mines, through the assessment of medium-term costs associated with developing new mine capacity, to long-term evaluations of the economics of mineral supply from the start of exploration. The complexity of the analysis increase s with the scope and timeframe of interest. Many factors are involved. One component of competitive position is the quality of the mineral resources available. Other key factors include existing technology, wage and salary rates, labour productivity, the cost of capital, infra structure requirements, distances from sources of materials supply an d to mineral markets, management attributes, organizational efficiency, government mineral policies (particularly taxation), and inflation and exchange rates. The paper fits within this competitive position framework.The variable economic conditions which exist within Canada have a direct bearing on the viability of mine development and, thereby, on mineral exploration potential. The paper examines locational aspects of Nova Scotia 's competitive position."

Jan 1, 1986

By Mohsen Amir-Rahmat

The ore of Sarcheshmeh copper deposit that has been located in the south ?east of Iran, contains four type of rock that they have their specific hardness and strength according to their alteration type and mineralization. Blasting of these various types of mine rocks prepares various types of size for the product of mine as the feed of concentration. Along the crushing of this feed a few factors effect on the efficiency of the crushing unit. The aim of this project has been the consideration of the effect of ore size on the efficiency of crushing unit. For this investigation along the year 2000 A.D., six sample from feed and six sample from product of crushing unit have been prepared. The results of the screen analyze of these samples has shown that the size of feed has been lesser than the primary plan and the size rate of the product has been bigger than the primary plan. Also in this research the effect of feed size on the quality of product size has been considered.

May 1, 2003

By W. H. Gauvin, N. J. Themelis

I N ADDITION to its practical importance in the beneficiation of iron ores and in direct-iron processes, the study of the reduction of iron oxides involves many aspects of challenging theoretical interest. The complexity of the reduction process combined with the fact that under different experimental conditions the controlling stage for the reaction may not necessarily be the same, has led experimenters in this field to a wide diversity of opinion regarding the reaction mecl1anism. As a rule, each investigation has been restricted to the study of one or two variables over a comparative]~• narrow range of experimental conditions, and consequently, it be-comes necessary to examine the significance of each published work in the light of the results of other experimenters in the field.

Jan 1, 1962

By D. B. Dreisinger, M. Rasouli

"Developing technology to address the environmental hazards associated with selenium in mine-impacted waters has been a serious challenge. Ion exchange (IX) has been identified as a potential treatment technology. This paper begins with a review on selenium adsorption with commercially-available basic anionic exchangers (BAS). It then looks at the use of resins for selenium removal via modification with the addition of -O, -N, or -S-containing chelating ligands and chelating polymeric ion exchangers pre-loaded with immobilized metal cations. The synthesis of chelating exchangers requires a final product with a highly stable metal in the ligand-metal complex. The nature, oxidation state, size, and affinity of the metal for the target oxyanions and the size, degree of protonation and space configuration of the oxyanion are among critical factors affecting the oxyanion uptake. There is a limited number of studies on the critical parameters affecting the selenium affinity for chelating exchangers. Such a study could fill in the gaps of our understanding of selenium-metal-chelating ligand interactions and assist in developing a new ion exchanger. In addition to commercial IX resins, layered double hydroxide materials (LDH) have received attention for oxyanion removal from waste water. The adsorption capacity of the LDHs are affected by the crystallinity of LDH, the nature of metal components, the ratio of metals, charge and type of anion, and the space between the layers. In particular, the Friedel phase (FP), a member of the LDH family, showed high adsorption capacity for selenate removal from synthetic solution. A study is currently underway at the University of British Columbia to investigate the effect of different synthesis methods and aging on the suitability of FP for selenium removal from mine waste water."

Jan 1, 2017

By Kevin M. Ansdell, Irvine R. Annesley, Christine L. Mckechnie

The U-Th-REE mineralization at Fraser Lakes Zone B is hosted by granitic pegmatites and leucogranites, which lie along the deformed contact between Paleoproterozoic metasedimentary gneiss of the Wollaston Group and Archean orthogneiss, approximately 25 km from the southeastern edge of the Athabasca Basin. The pegmatites/leucogranites are subcordant to concordant with the regional foliation and are concentrated within a northeast-plunging antiformal fold nose, the study area, which lies west of Fraser Lakes. The mineralized pegmatites/leucogranites in the western part of the study area (Group A) are typically enriched in U (± Th) with Th/U ~1, and contain uraninite, thorite, zircon, and allanite. Those intruding the central part of the study area (Group B) are generally enriched in Th and LREE, with Th/U >2, and contain monazite, thorite (commonly U-enriched), and zircon. The pegmatites and leucogranites in Group A tend to be slightly enriched in SiO2 and depleted in TiO2 relative to those in Group B and are interpreted to represent more evolved crustal melts. Both groups are peraluminous and show varied chemistry. Partial melting (~850ºC and 9 kbar) of a metasedimentary rock-dominated source, entrainment of accessory minerals as xenocrysts, and assimilation-fractional crystallization processes combined to enrich the granitic pegmatites/leucogranites in U, Th, and REE elements. Transfer of melt from the source region to the crystallization sites was assisted by deformation within and along major structural zones, such as the folded Archean-Paleoproterozoic discontinuity. The character of mineralization and structural control in the study area is reminiscent of the alaskite-hosted deposits at Rössing, Namibia.

Jan 1, 2013

By J. R. Emery, D. F. Coates

"FOUR PAPERS ON CEMENTED BACKFILL were given at the Annual General Meeting of The Canadian Institute of Mining and Metallurgy in 1970:Weaver, W. S., and Luka, R., ""Laboratory Studies of Cement-Stabilized Mine Tailings"".Pasieka, A. R., Beattie, H. F., and Espley, G. H., ""Cemented Hydraulic Backill within the Falconbridge Group of Companies"".McLeod, P. C., and Schwartz, A., ""Consolidated Fill at Noranda Mines Limited (Geco Division)"".Clement, W. P., and Sokoloski, R., ""Pumping Cemented Backfill"".These four papers give the impression of a development in mining technology that has been substantially completed. Somewhat over ten years ago, The Inter-national Nickel Company of Canada, Limited and Falconbridge Nickel Mines Limited started experimenting with the addition of Portland cement to mill tailings to produce improved backfill and cheaper floors for scraping. Shortly after, the Canada Cement Company Limited (now Canada Cement Lafarge Ltd.), with full support of the two mining companies, started an extensive research program to provide the technologic-al data necessary to exploit what was obviously going to be a significant development in mining technology."

Jan 1, 1970

By M. Morin

"This paper examines the design issues associated with the integration of mineral processing within underground mining using a total systems approach. It demonstrates conceptual integrated system design options appropriate to a range of geological scenarios. Particular reference is then given to a case study of stoping in narrow base metal veins.The performance of such integrated systems in terms of productivity, economical and environmental criteria is demonstrated by means of simulation. Particular attention is given to the potential benefits to mine waste management. Processing technologies appear to offer genuine potential benefits, while underground mining methods may need to evolve further to facilitate full integration. This paper is based on industry supported research aimed at developing selective and clean underground mining systems. IntroductionTotal systems thinking is simple in principle but complex to implement. The premise is that to achieve optimum effectiveness and efficiency from a system, the complete system must be considered. Using this approach will avoid the situation where the optimization of a localized component of any system results in a negative impact on the performance of the complete system. Take for example the parts manager who reduces inventory costs without consideration of the consequences to the plant. If the plant goes down and a part is unavailable, it would then cost significantly more than the cost of having it in inventory (Ackoff, 1994).A tool for applying total systems thinking toward understanding and analyzing different mineral extraction options is the structured analysis and design techniques (SADT). Originally developed by Ross (1977), SADT is a formal systems engineering methodology (FIPS PUB, 1993) for process and enterprise modelling (Marca and McGowan, 1993). Figure 1 presents a highlevel structured analysis of the traditional or conventional metal extraction process. There are three sequential processes with several arrows entering or exiting each process. In SADT, inputs always enter from the left-hand side and exit as outputs of the process on the right-hand side. Constraints affecting the transformation of inputs to outputs enter the process from the top while resources or mechanisms enabling the transformation enter from the bottom. SADT is a hierarchical decomposition technique and further analysis is undertaken by expanding downward into each process."

Jan 1, 2003

By N. T. Oo, L. D. Hutton

"The Banora Point Upgrade Project is a 2.5km long six-lane divided freeway in northern New South Wales, Australia. The geology at the project area comprises a volcanic succession of variably weathered basalt flows and agglomerate deposits that reach 48m in thickness and overlie Mesozoic sedimentary rocks. A site specific rock classification system was developed that characterised all the rock units based on the engineering properties governing the rock mass behaviour i.e. intact rock strength and defect characteristics (spacing, aperture, infilling, wall roughness and weathering) irrespective of the geological origin. This approach simplified the design and the on-site verification processes. Based on this classification system, rigorous quantitative statistical assessments of the available geological information including various laboratory and field testing were performed to derive the geotechnical design parameters for various rock classes. These parameters were used to complete geotechnical designs of retaining wall systems. INTRODUCTIONThe Banora Point Upgrade Project is a 2.5km long six-lane divided freeway in northern New South Wales, Australia. The key features include two interchanges, a 300m long viaduct, a large cutting through Sexton Hill with an associated 100m wide Land Bridge and retaining walls reaching 490m long and up to 22m high. This paper focuses on the derivation of representative geotechnical parameters for geotechnical design of the retaining structures supporting Sexton Hill Cutting including bored pile retaining walls and soil nail walls. The geology at the project area comprises a volcanic succession of variably weathered basalt flows and agglomerate deposits that reach 48m in thickness and overlie Mesozoic sedimentary rocks. Due to the complex geological nature of the site, an understanding of the regional and local geology, the typical behaviour of individual geological units and the implication of onsite variations from design intention are the ultimate challenges to the geotechnical engineer in order to select representative geotechnical parameters for design."

Jan 1, 2015

By D. D. Tannant

An experimental and numerical study was conducted on the geomechanical behaviour of oil sands during penetration tests in which a steel wedge with an apex angle of either 20 degrees or 30 degrees was forced into compacted oil sands. The boundary conditions simulated in the laboratory tests are similar to shovel penetration into oil sands. The objective of the laboratory tests was to measure the force required to push a steel wedge into compacted oil sands. A wedge penetration test differs from conventional triaxial tests in that much more shear is generated. The laboratory data was needed to improve calibration of micro-mechanical input parameters for a two-dimensional discrete element model of oil sands constructed with Particle Flow Code (PFC). Initial model calibration was performed with triaxial test data and then a PFC model of the wedge penetration test was constructed. The measured force-displacement behaviour of the steel wedge was compared with PFC modelling results. It was found that different combinations of PFC particle and bond parameters could equally well replicate the laboratory triaxial compression data for bitumen-rich oil sands. When the wedge model was run, it was found that the resulting force required to penetrate the wedge into the oil sands was about four to six times higher than that measured. This clearly indicates that further research is required to improve the predictive capability of PFC models of oil sands.

Jan 1, 2002

By B. S. Kim, Y. D. Kim, T. S. Kim, T. B. Kim, H. J. Chae

"The Nd-Fe-B scrap was placed in Fe crucible with pure Mg in an Ar atmosphere, and the scraps were melted using an induction heating method. The effects of experimental parameters such as melting temperature (range of 993K to 1073K) and holding time (15min-600min) on the ability of extraction were investigated. The microstructure and diffusion layers were analyzed by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), and the constituent phases were characterized using XRay Diffraction (XRD). Diffusion of Nd through the Nd-Fe-B scrap into liquid Mg was described, and the diffusion coefficient of Nd in liquid Mg was estimated.INTRODUCTIONNd-Fe-B magnets are usually produced either from comminuted melt-spun ribbons as bonded magnets or hot pressed bulk magnets, or by sintering in conjunction with prior green compaction in an applied magnetic field (Sagawa et al., 1984). These magnets have been widely used for various electromechanical and electronic devices such as voice coil motors (VCMs) and magnetic resonance imaging (MRI) (Samardzija et al., 2012; Matsuura et al., 2006). The production of the Nd-Fe-B magnets is increasing by about 20% per year because of their excellent magnetic properties. However, the expansion of Nd-Fe-B magnet market induced a concern for the scarcity of Nd at the aspect of natural resource. Therefore, the development of an effective recycling process for Nd-Fe-B magnet scraps is an extremely important issue from the viewpoint of resource and energy conservation. Several recycling processes for the Nd-Fe-B magnets have been proposed (Uda et al., 2002; Lyman et al., 1993]. It has been reported that the best separation of rare-earths from the Nd-Fe-B magnets is obtained by sulfuric acid dissolution followed by precipitation of recyclable rare-earth salts. However, this process can make a large amount of waste water including dangerous solutions. Recently, (Xu et al., 2000) have reported a technique to extract Nd from 18Nd-72.4Fe-0.9B-1.82Pr-5.3Dy (wt.%) magnet scrap by using liquid metal extraction (LME) processing. However, these techniques seemed to be difficult for application, because the scraps consist of an infinitesimal amount of other minor elements (Pr, Dy, Cu, Al and Tb), and these minor elements can make a new intermetallic compounds with Mg. Also, some oxides or the plated Ni metal can be preventable to reaction between solid-liquid (S/L) interfaces. For these reasons, the substantive reaction mechanism between Mg and Nd-Fe-B scrap is not clear. In this study, the simple composition of 33Nd-66Fe-1B (wt.%) magnet scraps were prepared using an induction melting process. The effects of the experimental parameter on the diffusion properties between Mg and scraps were investigated to determine whether these methods could be used in industrial application in a liquid metal extraction (LME) process."

Jan 1, 2012

"10.1. IntroductionAs discussed by Westland (1981), the six platinum-group elements (PGE) belong to the Group VIII transition metals, to which iron, nickel and cobalt also belong. The chemical similarity between these nine metals accounts for the fact that they tend to be concentrated together as a result of geological processes. These processes started to effect the distribution of these metals at the very beginning of the earth's history.The first line in Table 1 gives the concentration of nickel and certain other Group VIII transition metals in carbonaceous chondrites, those meteorites with a composition that is believed to reflect best the composition of our planetary system apart from hydrogen and helium. The second line is the estimated concentration of the same elements in the earth as a whole. It is seen that these two estimates are quite similar, the earth being perhaps 2 to 3 times richer in these particular metals than the planetary system as a whole. The reason for this is not fully understood, but it may be due to the earth being formed by the accumulation and capture of a greater proportion of iron (and therefore siderophile-rich) than stoney (and therefore siderophile-poor) planetesimals than the planetary system itself.The third line in Table 1 is the average composition of the crust of the earth. With the exception of iron, all of the Group VIII transition elements are rare in the crust, present at concentrations of It tOO to Itt ,000 of that of the bulk earth. This is because the outstanding chemical characteristic of this group of elements is their siderophile nature; that is, their tendency to alloy with metallic iron. Because of this, once the earth became molten very early in its life history, these elements dissolved in the molten iron present at this stage and were removed from the outer accessible parts as this dense liquid sank to the centre of the earth to form the core. Although iron was the main instrument of concentration of the Group VIII metals, its much greater over-all abundance and its ability to combine with oxygen more easily than the others in the group means that significant amounts still remain in the oxidized portions of the earth.The fact that most of the Group VIII metals are available to use in workable concentrations at all is that they are 5 to 30 times more concentrated in the earth's mantle than the crust, as shown in line 4 of Table I. There has been a constant, if slow, interchange of matter between the mantle and the overlying crust throughout most of the earth's history and, under certain circumstances, this interchange has given rise to economic concentrations of metals."

Jan 1, 1979