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By Te Gao

It is a general expectancy that in most of the construction and renovation project, the contractor is going to hand over the as-built documents to the owner or the facility management team at the completion of the project. The main challenge for the handover process is to ensure the completeness of the captured building information and the accuracy of it in terms of how well it represents the reality. Building information models (BIMs) can be used as an information repository to store and deliver as-built information. However, due to changes made in the construction and renovation phases and errors made in the design and modeling phases, discrepancies can exist between BIMs created in the design phase (asdesigned BIMs) and actual building conditions. Laser scanning technology is able to efficiently capture accurate geometric information, which provides an opportunity to identify and quantify discrepancies and update as-designed BIMs into as-built BIMs. This paper presents a case study, within which the asdesigned BIM of a newly renovated research lab was updated into an as-built BIM using laser scanned data captured in the renovation phase. This paper introduces the challenges associated with the updating process for the as-designed BIM. In order to address these challenges, this paper introduces a framework that supports the update of an as-designed BIM by incorporating point clouds captured by the progressive laser scans.

Aug 1, 2013

By P. G. Keohane, J. S. Drake

"Cominco's Polaris Mine is a lead-zinc underground operation that began commercial production in early 1982. The mine site is located on Little Cornwallis Island in the Canadian Arctic at a latitude of 75°23'N and at a longitude of 96°55'W. The nearest settlement, Resolute Bay, some 100 kilometres southeasterly from the mine, is accessed from the mine by light aircraft. The mine site can be accessed by sea during the six-week ice-free period each year. During this time all major operating supplies are brought to the mine and the lead and zinc concentrate products are shipped out to market.GeologyThe Polaris orebody lies near the top of the Thumb Mountain Formation of Ordovician age. This formation is a relatively homogeneous section of thin to medium bedded limestones which are brecciated and dolomitized in the area around the orebody. The deposit is described as a Mississippi Valley-type orebody. Ore minerals are sphalerite and galena with the waste being predominantly dolomite with calcite and marcasite. The ore is quite porous with voids being generally filled with ice as the mineralized zone lies entirely within permafrost. Reserves consist of about twenty million tonnes of ore grading 3.8% Pb and 14.3% Zn with a further three million tonnes of inferred ore at a slightly lower grade.The orebody strikes in a north-south direction with the hangingwall dipping at about twenty degrees to the east. It is generally conformable with the stratigraphy. The footwall in the western portion of the orebody, the Panhandle, lies about 10 to 30 metres below the hangingwall. To the east the footwall drops sharply, creating an orebody height of up to 110 metres in what is referred to as the Keel Zone. The Panhandle Zone has typically 80 - 110 metres of cover above the hangingwall , About 25% of the reserves are in the Panhandle Zone, the remainder being in the Keel Zone. Figure I illustrates a plan view of the orebody relative to other surface facilities on the property and Figure 2 illustrates a simplified section through the Panhandle and Keel Zones."

Jan 1, 1985

By M. W. Mikhail, R. J. Mikula

"Funding has been made available through the National Energy Program to build a mobile fine coal treatment plant. The plant is intended f or field application and also to upgrade the existing pilot plant facilities.Western Canadian coals with high proportions of fines (due 10 their friability) cause high losses of fine coal to the reject and in turn reduce the over-all recovery of saleable coal. Eastern Canadian coals with high amounts of sulphur of ten require crushing to fin e sizes to liberate pyrite and therefore need effective and efficient separation of these fine sulphur particles. The difficulties involved in solving these problems are two-fold. One is the reluctance to experiment in an operating wash plant and the other is that laboratory scale testing often cannot be extrapolated to the plant environment. The mobile fine cleaning plant with its ability to operate at existing coal preparation plants across Canada and with its flexibility in implementing flowsheet option s and close monitoring of fine coal circuit variables, is ideally suited to solve these fine coal cleaning problems. The mobile plant objectives are to design and optimize flowsheets, evaluate and improve fine cleaning circuit operations and 10 lest new process monitoring and control equipment.The schedule for construction and the required resources will be outlined along with flowsheet options and the general R&D philosophy of the mobile plant.IntroductionIn relation to coal preparation technology, Canadian coal s can be grouped as Eastern coal, Rocky Mountain metallurgical coal and Foothills high volatile bituminous coal. The eastern coals have high sulphur contents and in some cases require crushing or even grinding to liberate the fine pyrite . Rocky Mountain metallurgical coals often occur in highly sheared seams which have been subjected to rapid coalification. The high friability of these coals means that degradation during mining, handling and processing is extensive and results in large amounts of fine s ranging between 20 and 60% by mass of the wash plant feed. The widely varying geo logical structure and exposure to the elements results in partially oxidized coals which perform inconsistently in the traditional method of fine cleaning by flotation . Foothills high volatile bituminous coals for thermal use are frequently interbedded with soft shales and bentonitic clays. These clays disintegrate during washing and swell, producing large volumes of tailings. The presence of clays in plant circuits, particularly fine circuits, tends to increase the viscosity and may cause deterioration of the fines density separation and increase magnetite losses. In view of the fact that fine coal cleaning is the most difficult aspect of coal preparation , a research program is being established to study the factors involved and to offer some solutions.A recent performance evaluation of Canadian washeries showed that yield losses in the minus 2 mm coal circuits were approximately ten times those occurring in the coarse coal circuits(1). Because 2 mm x 0 coal represents 30 to 70 per cent of the raw coal, these losses can be considerable . The operating and capital costs of beneficiating minus 6 mm coal are about four to five times higher than for plus 6 mm coal. In the case o f minus 2 mm coal the costs are even higher. The economic importance of the fine coal cleaning cannot be over emphasized and as a result, the CANMET R&D program is geared for fine coal beneficiation."

Jan 1, 1984

By R. Gatzweiler

The Key Lake nickel-uranium deposits are situated within the Wollaston domain of the Churchill structural province. The host rocks of the two orebodies are of Aphebian and Helikian age. The orebodies occur mainly within a 5.2-km-Iong, northeast-trending zone which coincides with the intersection of the sub-Athabasca unconformity and a reverse fault striking east-northeast. The principal controls of mineralization are structural and lithostratigraphic (i.e., post-Athabasca faults, the sub-Athabasca unconformity and graphitic metapelites in the lower Aphebian, close to the Aphebian/Archean unconformity). Grades of up to 35% U3O8 and 20% Ni are recorded over intervals of up to 2 m. Some hypogene zonation exists and the nickel mineralization tends to underlie the high-grade uranium ore. The ore minerals include pitchblende, a-U307, coffinite, gersdorffite, millerite, niccolite, bravoite, zoisite, sericite, chlorite and kaolinite. The kaolinite is a post-ore, supergene alteration product. Chemical studies of the sub-Athabasca paleo weathering profile sho w that regolithization is characterized by depletion in Si02 and K20 and concomitant enrichment in Al203 and perhaps MgO. In the paleoweathering profile the ferromagnes ian minerals are chloritized, the Ksfeldspars sericitized and the plagioclase saussuritized. Preliminary geochronologic data from the ores reveal U/Pb ages of -1228 my, - 960 my and 89 my, and Rb /Sr data indicate basement ages of -1850 my and - 1372 my. Aphebian pelitic protoliths, carrying U and Ni, may have released some metals during post-Hudsonian weathering, and minor concentration in structural and geochemical traps may have taken place prior to the deposition of the Athabasca strata. However, it is felt that the bulk ofthe ore-grade mineralization wasgenerated after the deposition of the Athabasca formation and after faulting, probably during a major regional thermal/ intrusive episode of Grenvillian age. Several episodes of remobilization took place between 1228and 89 my ago.

Jan 1, 1979

Presentation Overview ?WRDC Purpose and Activities ?Women in Trades, Technology and Operations (TTO) Occupations ?Factors in Successful Recruitment / Retention of women (VBNC) ?Recruitment and Retention Strategies ?Conclusion Women in Resource Development Committee (WRDC) ?Incorporated in 1999 as a Not for Profit Organization ?Based in Newfoundland and Labrador ?Works to Increase the Participation of Women in Natural Resource Industries ?Research (Using Gender-Based Analysis) ?Career Exploration Programs for Women and Girls ?Outreach and Advocacy ?Policy Development ?Public Awareness and Education ?Gender Sensitivity Training ?WRDC Educational Resource Centre

May 1, 2006

By Gerhard Heinrich

"The composition and the possible utilization of a slag sample from a nickel smelter operation in the Sudbury district were investigated. The sample containing 0.136% Ni, 0.10% Co and 0.29% Cu could be characterized as a fayalit e slag with a sulphide bearing glass matrix. While the fayalite contains most of the Co, Ni is enriched within both sulphides and fayalite. Cu is only present in higher amounts in sulphides or metallic droplets. This, as well as the small grain sizes of the mineral phases, inhibits significant enrichment by mechanical methods. However preconcentration is possible by means of magnetic separation. An effective hydro metallurgical approach proved to be oxygen pressure leaching with sulphuric acid. Accordingly, the method proposed for processing the investigated slags is to combine the normal utilization as coarse construction material with pressure leaching of the fines and the ground upgraded magnetic fraction. Besides the recovery of base metals, the leaching process yields fine-grained residues, which, after addition of CaD, will set to a cement-like material, or can be used as a pozzolanic cement colour. INTRODUCTIONDuring the pyro metallurgical processing of nickel ores, the valuable metals nickel, cobalt and copper are enriched within the sulphide matte, similar to the smelting of copper ores. The resulting waste materials are slags, which may still contain valuable metal contents of up to 0.5% or above . These contents are close to the cut-off grades of some nickel-cop per-cobalt deposits. The methods that are used to recover copper from slags comprise in general further pyro metallurgical treatment, often after enrichment by flotation. Another area of application for such slags is their use as construction material. However, this might cause environmental problems if nickel containing dusts are produced.Based on one example, the characerization and a possible way of complete utilization of nickel smelter slag s as construction materials in combination with partial base metal recovery are described in this paper. The investigated slag sample was obtained from a dump site in the Sudbury district, Ontario. Detailed test series for process optimization were not possible during this study due to the limited available sample size."

Jan 1, 1989

By H. Nouranian, M. Askari

GOLGOHAR Mining & Industrial Co., with annual production of 16 million tons, is one of the largest pelletizing and iron ore supplier in Iran that recently this year, because of using mineral processing techniques and extraction of ore body positioning between the metamorphic rocks, about 150 million tons of dry tailings has been created as a result of concentrate production. On the other hand, many environmental issues such as groundwater pollution have been developed by sulfide and silicate gangue minerals, which containing heavy metals such as mercury and arsenic. In this study, a new product with high added value has been introduced for the company by identification and extraction of industrial minerals in dry tailings. Also, by removing large masses of dry tailings, environmental pollution sources were gradually eliminated. This method can be used as a modern waste management approach in the world.

Jan 1, 2017

By Roger Lacroix

Presentation outline Project definition Characterization of mine ventilation systems Strategies in place and results Detailed study (2 mines) Other potential energy savings Conclusions Next steps

Feb 1, 2008

Agenda 1.Energy consumption and energy costs ?focus and failings 2.Energy efficiency methodologies, people and supporting tools 3.Energy cost saving case studies from three minerals processing plants 4.The operations team and the supporting role of Operations IT 5.Conclusion: Reducing energy consumption and energy costs There are many good Energy Efficiency Methodologies ?Energy and GHG Emissions, Management Guidance Document, The Mining Association of Canada ?Energy Savings Toolbox ?An Energy Audit Manual and Tool, Canadian Industry Program for Energy Conservation (CIPEC) ?Lean and Energy Toolkit, Achieving Process Excellence Using Less Energy, www.epa.gov/lean ?Energy Efficiency Opportunities Assessment Handbook, www.energyefficiencyopportunities.gov.au

May 1, 2010

By Franco Chiesa, David Levasseur, Bernard Duchesne

A 500kg aluminium AlSi7Mg03 casting has been poured and the metallurgical quality at different locations inside the casting has been thoroughly investigated. It included measuring the local tensile properties (YS, UTS, El) in the T6 condition, the dendrite fineness (DAS) and the level of microporosity. A correlation was found between the microporosity level, the local solidification time and solidus front velocity; this correlation allows to predict the porosity level in large aluminium castings (solidification times between 20 and 200 minutes). Quite expectedly, properties varied widely within the casting and the actual mechanical properties were much less than the "textbook values" based on measurements carried out on separately cast standard specimens. A correlation between the secondary dendrite arm spacing (DAS) and the local solidification time was in keeping with previously published data. Finally the conditions to obtain an acceptable finish on machined surface were determined.

Jan 1, 2014

By C. Cekerevac

The paper addresses some geotechnical issues related to the construction of the Deriner dam and HEPP. Design considerations and rock stabilization measures are presented for the excavations which took place in a highly fractured and weathered rock mass prevailing on site. Particularly, the shallow excavations for the overflow spillways tunnels are discussed. These present huge openings that are 12 m wide and 18 m high in portal areas, with an overburden of approximately 20 m, for which numerical finite element analysis and structural discontinuity analysis have been performed to ensure safe excavation process and future operation.

May 1, 2009

By Sebastian Siebert

Unmanned Aerial Vehicles (UAV) as a data acquisition platform and as a measurement instrument have become attractive for many surveying applications in civil engineering. However, their performance is not well understood for these particular applications. The specific scope of the presented work is the performance evaluation of a UAV system that was built to rapidly acquire mobile 3D mapping data for large earthmoving construction sites. Details to the components of the developed system (hardware and control software) are explained. A novel program for photogrammetric flight planning and its execution for the generation of 3D point clouds from digital mobile images is explained. A performance model for estimating the position error was developed and tested in several realistic construction environments. Results to these tests are presented as they relate in particular to large excavation and earth moving construction sites. Results and experiences with the developed UAV system are in particular useful for researchers or practitioners in need for successfully adapting UAV technology for their application(s).

Aug 1, 2013

By Robert Boutilier

For more information on what the social licence means, see the following: Joyce, S. and Thomson, I. 2000. Earning a social licence to operate: Social acceptability and resource development in Latin America. The Canadian Mining and Metallurgical Bulletin, 93(1037) Nelson, J. and Scoble, M. 2006. Social License to Operate: Issues of Situational Analysis and Process. Vancouver, BC: Department of Mining Engineering, University of British Colombia. Thomson, I. and Boutilier, R.G. 2010. The Social License to Operate In P.Darling, (Ed.), SME Mining Engineering Handbook: Littleton, CO: Society for Mining, Metallurgy and Exploration. Much of what has been written and said about the social license to operate focuses on what the company has to do or not do. But the social license is a two-sided relationship. We also need to look at what the community has to do, or not do, in order to be capable of issuing a social license that is meaningful.

May 1, 2010

By Nickvinder Bhath, Johnson Matthey Plc, Jamie Baker, Daniel Kim, Jeff Lucht, Shijie Wang

"Precious metals (PM) in copper anode slimes are traditionally recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of precious metals, including relatively inert metals such as gold and platinum group metals (PGMs). In this paper, a new method to recover PGM from complex and difficult feed streams is described. Using a proprietary Advanced Ion Exchange (AIX) adsorbent which has a high selectivity for PGMs over other metals and can achieve high PGM mass loadings with a series of incredible pilot test data plus the business case generated from the study results are also presented in the paper.INTRODUCTIONPrecious metals in copper anode slimes are traditional recovered by pyrometallurgical processes. Due to the compliance with increasingly stringent environmental regulations, it has made hydrometallurgical processing an attractive method for recovery of many metals, including relatively inert metals such as gold and platinum group metals (PGMs). Fully hydrometallurgical processes for extraction and recovery of gold and silver from copper anode slimes were employed in major copper refineries since 1995, which was first developed at Rio Tinto Kennecott Utah Copper.In Rio Tinto KUC process, the wet chlorination and gold solvent extraction were utilized to enable recovery of gold and silver as well as other metal compounds. The availability of water and the interaction and amenability of gold processing in water-based solution makes it possible that gold and silver are produced in only five days, compared with a traditional pyrometallurgical process that took 45 days. Most copper refineries are still following the tradition, but the use of hydrometallurgical technologies is increasing as the world demand for metals increases, energy utilization, and environmental viability."

Jan 1, 2016

By Margaret Armstrong, Normand Champigny

"In order to define the ore/waste boundaries as finely as possible, mine planners often insist on kriging very small blocks (relative to the spacing of the available sample grades). These kriged estimates for very small blocks are over-smoothed. For several simple sampling patterns the relation between the block size and the variogram range, and the kriging results were studied. Meaningful estimates of individual blocks are obtained when the variogram range is large compared to the block size and the sample spacing. For a variogram range less than half the sample spacing, the kriged block estimates were found to be uncorrelated with the actual grades. The over-smoothed estimates should not be used for calculating recoverable reserves IntroductionNowadays most mining companies know that the geostatistical estimation method, kriging, gives the best estimates of individual block grades. As most mining engineers and geologists are now familiar with the basics of geostatistics, the definitions of the variogram and of kriging will not be repeated here. An appendix containing definitions and mathematical formulae is given at the end of the article for the sake of completeness.Even though it is well known that the kriged estimates for very small blocks are over-smoothed, mine planners who want to define the ore/waste limits as finely as possible (especially for selective underground mines), are often tempted to krige very small blocks. So we ask how small is ""too small""? Clearly ""smallness"" cannot be expressed in yards or metres. It depends on the nature of the orebody under study and this is reflected in the variogram model chosen to describe it.To answer this question, the changes in four key parameters are studied:• the kriging variance,• the variance of the estimated grade,• the slope of the linear regression of the true but unknown grade on its estimated value, and• the coefficient of correlation between the actual grade and the estimate;as a function of the block size and the variogram range. (Definitions of these four parameters are given in the appendix). Ideally the kriging variance should be low while the variance of the estimated grade should be equal to the dispersion variance of the blocks. The slope should be l.0, and so should the correlation coefficient.These four parameters have been calculated for several simple 2-D examples. The effect of using kriged block estimates that are too heavily smoothed are shown, and the dangers of trying to use these estimates for predicting recoverable reserves for small blocks (i.e. selective mining units) are pointed out."

Jan 1, 1989

By Emmanuel John M. Carranza, Martin Hale

Abstract- An application of logistic regression to mapping of gold potential in the Baguio district of the Philippines is described. Categorical map data such as lithologic units and proximity classes of curvi-linear features, based on spatial association analyses, are quantified systematically and used as independent variables in logistic regression to predict the probability for presence or absence of gold mineralization. Regression experiments to compare between using all independent variables that are associated spatially with the response variable and using only statistically significant independent variables are performed. The results of the regression experiments are similar; however, the use of all independent variables produces slightly optimistic results but better prediction rates for the known gold deposits in the test district. At least 68% of the ‘model’ large-scale gold deposits and at least 76% of the ‘validation’ small-scale gold deposits were predicted correctly. The predicted geologically favorable zones are also similar to delineated geochemically anomalous zones. The technique presented using logistic regression as a data integration tool is effective for geologically constrained technique of mapping mineral potential.

Jan 1, 2001

By D. Saramak, T. Gawenda, Z. Naziemiec, A. Saramak

"Crushing and grinding operations are burdensome to the environment due to generating large amounts of dust, noise and waste during course of comminution operations. An indirect negative contribution of industrial crushing processes is an increase of carbon dioxide emissions, which is a byproduct in energy production processes. On the other hand comminution processes in ore enrichment technology are essential due to liberation the useful minerals from the gangue, and producing the demanded particle size fractions of products. The article concerns investigation over negative influence of comminution devices on environment in terms of dust and noise emissions. Several various crushing devices were under investigations, both in laboratory and in industrial scale.The obtained results were analyzed in terms throughput and energy consumption achieved in various crushing devices. The test results allow to conclude that an intensity of dust generation for individual types of crushing devices is varied. An additional aim of this article is to link the aspect of mineral processing with its environmental impact and hence an influence of raw materials beneficiation industry on the quality of life of residents in immediate and close vicinity.INTRODUCTIONMineral raw materials beneficiation processes are an integral part of multi-stage processing of coal, iron ore and non-ferrous metals, production of aggregates, cement, or precious metals and stones. One of the common features of all beneficiation operations is their high energy consumption, which is mainly connected with various operations of feed particle size reduction. Comminution processes in ore enrichment technology are essential to expose and liberate the useful minerals from the gangue, while in aggregate production processes – to obtain the demanded particle size fractions of products. Crushing operations are characterized by a high degree of negative impact to the environment and humans, mainly due to:• High electricity consumption, which indirectly contributes to the increased emissions of carbon dioxide into the atmosphere, since CO2 is often one of the byproducts of energy production;• Relatively rapid wear of device working parts, what forces a production of spare parts and involvement of steel industry;• Intense dust pollution generated during crushing and grinding processes. This is one of the factors affecting the air quality and the consequent deterioration of the living conditions of inhabitants near mines and processing plants; and • Excessive noise emissions."

Jan 1, 2016

By L. Nastac, Y. Xuan

"The metal-matrix-nano-composite (MMNCs) in this research work consists of an A356 alloy matrix reinforced with 1.0 wt. % SiC 50 nm diameter nanoparticles that can be dispersed within the molten alloy matrix via ultrasonic stirring technology (UST) and induction melting and stirring processing. The necessary ultrasonic parameters to achieve the essential cavitation for adequate degassing and refining of the A356 alloy as well as the optimum fluid flow characteristics for uniform dispersion of the nanoparticles into the A356 alloy matrix have been investigated in this study by using computational fluid dynamics (CFD) modeling with a magneto-hydro-dynamics (MHD) model and an UST cavitation model.The MHD model accounts for turbulent fluid flow, heat transfer and solidification, electromagnetic field as well as the complex interactions between the solidifying alloy and nanoparticles by using ANSYS Maxwell and ANSYS Fluent Dense Discrete Phase Model (DDPM) and a particle engulfment and pushing (PEP) model.INTRODUCTIONAluminum matrix nanocomposites can offer outstanding properties, including low density, high specific strength, high specific stiffness, excellent wear resistance and controllable expansion coefficient, which make them attractive for numerous applications in aerospace, automobile, and military industries field (Bozic, 2010, De Cicco, 2009, Elshalakany, 2014, Goh, 2006, Jia, 2013 and 2015, Liu, 2014, Reihani, 2006, and Su, 2010).As shown in literatures (Aki, 1999 and Mussert, 2002), it is highly advantageous to use nano-sized ceramic particles to produce metal matrix nano-composites (MMNCs) since similar ductility and higher strength with the metal matrix can be achieved. Currently, there are several fabrication methods of MMNCs, including mechanical alloying with high energy milling (Chen, 1997) , ball milling (Filho, 2003), nano-sintering (Groza, 1999), spray deposition, electrical plating, sol-gel synthesis, laser deposition, etc. The mixing of nano-sized ceramic particles is normally lengthy, expensive, and energy consuming.Ultrasonic Stirring Technology (UST) has been extensively used in purifying, degassing, and refinement of metallic melt (Jian, 2005, Khalifa, 2008, Eskin, 2002, Xu, 2004, and Meek, 2006) mainly because introducing the ultrasonic energy into a liquid will induce nonlinear effects such as cavitation and acoustic streaming. SiC nanoparticles are widely used as reinforcement particles due to their relatively good thermal and chemical stability. Ultrasonic vibration can improve the wettability between the reinforced nanoparticles and the metal matrix (Lan, 2004, Cao, 2008, and Yan, 2011), which will assist to distribute the nanoparticles more uniformly into the metal matrix. Ultrasonic cavitation in liquids causes high speed liquid jets of up to 1000 km/h. Such jets press liquid at high pressure between the particles and separate them from each other (Hielscher, 2005)."

Jan 1, 2016

By C. Díaz, A. D. Dalvi, C. E. O'Neill

Roast-reduction smelting (RRS) of nickel concentrate, combined with flash smelting of copper concentrate, was one of the process options that Inco considered as a means of meeting its 1994 sulphur dioxide abatement target at its Copper Cliff operations. RRS involves deep roasting the nickel concentrate in fluid bed roasters. The roaster off-gas is treated in a sulphuric acid plant, and the low sulphur calcine is reduction smelted with coke in an electric furnace to yield a sulphur- deficient matte. The latter material is converted to Bessemer matte in Peirce-Smith converters, with minimal evolution of sulphur dioxide, and the converter slag is reverted to the electric furnace. Excellent nickel and cobalt recoveries (Ire obtained. This paper discusses the development of RRS, including extensive commercial scale testing at Inco's Thompson Smelter, and its key operating parameters.

Jan 1, 1994

By Sarah Belair, Gauthier Deblonde, Valerie Weigel, Alexandre Chagnes, Gerard Cote

"Niobium and tantalum are strategic metals for electronic and alloys industries. They are produced by pyrometallurgy and hydrometallurgy but most of the niobium and tantalum production processes are not environmentally friendly. For instance, in the hydrometallurgical route, niobium and tantalum separation can only be achieved by liquid-liquid extraction in the presence of hydrofluoric acid by taking advantage of the difference in niobium(V) and tantalum(V) speciation in fluoride-based media. Therefore, the environmental footprint of hydrometallurgical processes for the production of niobium and tantalum could be clearly lowered by replacing HF or NH4F by greener media such as alkaline solutions in which high solubility of niobium(V) and tantalum(V) can be achieved.The development of such new efficient and environmentally friendly hydrometallurgical processes requires a fine description of the physicochemistry of niobium(V) and tantalum(V) in alkaline solutions. Unfortunately, literature data show a huge discrepancy on niobium(V) and tantalum(V) speciation in such media. This paper gives a brief overview of the niobium(V)-tantalum(V) production processes and paves the way to the development of alternative processes in alkaline media by presenting and discussing recent advances in the physicochemistry of niobium(V) and tantalum(V) in these media.INTRODUCTIONNiobium and tantalum are strategic metals since they are used for the production of alloys and super alloys, capacitors and magnets in strategic industries such as electronic, aeronautics and automobile. The main sources of niobium and tantalum are given in Table 1."

Jan 1, 2016