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By Mei-Yan Yang, Qiu-Ying Wang, Ltd. Yunnan Yuntong Zinc Co., Guo-Mu Chen, Meng-Yang Huang, Peng Zeng, Guo-Feng Li

"Historically, alot of jarosite was found in the leaching residue when leaching indium from secondary zinc oxide materials. The reasons for the formation of indium bearing jarosite were theoretically analyzed. The influence of controlling the acidity and the addition of reagents on the indium leaching yield during secondary zinc oxide processing was investigated. In order to increase the leaching yield of indium, a measure of controlling the creation and destruction of jarosite was proposed. The production data shows that the leaching yield of indium was increased from 60 to 96%, and the content of indium in leaching residue simultaneously decreased from 900g/t to 100–200g/t when implementing such controlling measures.INTRODUCTIONIndium does not occur as independent minerals in the earth’s crust and is mainly associated with complex sulphide minerals. Specifically some sphalerites can contain as much as 900g/t of indium. Most indium is recovered from by-products of copper, lead or zinc metallurgy. Therefore, the research on the recovery of by-products in non-ferrous metallurgy is important(Sinclair et al, 2006). The main technologies used for this objective in China include: •,pre-neutralization-reduction-precipitation indium process(Yu et al, 2008), •,countercurrent oxidizing acid leaching process and sulphation roasting-water leaching process(Cao, 2005), •,oxygen pressure acid leaching of zinc concentrate-P204 extraction process(Yang et al, 2006), •,doubleacid leaching-solvent extraction process on lead dross from a reverbatory furnace flue dust(Liu, 2003),•,an acid leaching-solvent extraction process on smelting ash(Zhouet al, 2005). Although high pressure and extreme conditions can be used to improve extraction from high iron bearing indium residues(autoclave processing), mild extraction with lower cost and lower environmental impact are preferred.This paper describes both how the indium extraction using mild conditions in a secondary zinc circuit was quite low and, how through XRD and chemical analysis jarosite formation was found as the main cause. The paper then proceeds to discuss a method for improving the leaching yield and the application of this method in industrial practice."

Jan 1, 2016

By James Tuer, John R. Goode, Jim Cambon

"Hudson Resources Inc. (Hudson) has defined a major resource of high purity anorthosite (calcium feldspar) assaying about 30% Al2O3 at the White Mountain (Naajat) deposit in Western Greenland. Extensive beneficiation and evaluation testwork has shown that the material can be simply beneficiated to produce a feed material ideal for the production of low-alkali E-glass used for making glass fibre. An offtake agreement is in place with a major US fibreglass manufacturer and, subject to the mine construction schedule, shipments are scheduled for late 2016 or early 2017. In parallel with the E-glass program, Hudson has completed an initial program of metallurgical testwork which shows that the White Mountain anorthosite can be processed by hydro- and pyro-metallurgical processes to yield either smelter-grade alumina (SGA), suitable for conversion to aluminium metal, or a high purity, chemical/specialty-grade alpha-alumina (CGA) commanding a premium price. The process includes dissolution of the anorthosite in hydrochloric acid, HCl sparging to precipitate aluminium chloride hexahydrate (ACH), recycle of the ACH filtrate to leaching with a bleed stream processed for HCl regeneration from CaCl2, and two-stage calcination of the ACH to regenerate HCl and produce SGA and/or CGA. Calcium silicate and amorphous silica are marketable by-products. This paper discusses the White Mountain anorthosite deposit; the process testwork completed to develop production processes for SGA and CGA; production plans, and indicative economics.INTRODUCTIONHudson Resources Inc. (Hudson) holds a 100% interest in the Naajat Exploitation Licence in Western Greenland that cover the White Mountain high-calcic anorthosite deposit. Anorthosite is a calcium aluminosilicate of slightly variable composition but generally containing about 30% Al2O3. The alumina content is similar to that in bauxite and anorthosite has long been studied as a feedstock for the production of alumina. Other potential uses include feedstock for the high-end fiberglass (E-glass) industry and as a filler for use in paint and plastics."

Jan 1, 2016

By Martin Irving

Adding Value to Canadian Diamonds - A Changing Diamond Industry - Diamond Mining - Diamond Manufacturing - Diamond Jewellery Markets - NWT Diamonds Changing Diamond Industry - De Beers ? privatization - Oppenheimers (45%), Anglo-American (45%), Botswana (10%) ? going retail - LVMH joint venture - New Players ? jurisdictions - Canada ? companies - BHP-Billiton - Aber Diamonds

May 1, 2002

By L. Klatzel-Mudry, D. J. Nikols, J. D. Hughes

"The Geological Survey of Canada Paper 88-21, A Standardized Coal Resource/Reserve Reporting System for Canada, is referenced by National Instrument 43-101 for the preparation of resource and reserve estimates on coal deposits. However, for all disclosure of mineral resources or mineral reserves for coal, issuers are required by NI 43-101 to use the equivalent mineral resource or mineral reserve categories set out in the CIM Definition Standards and not the categories set out in Paper 88-21. “Because the framework is based on Canadian deposits and their tectonic regimes, the Canadian Securities Administrators believe it is not reasonable to apply Paper 88-21 to foreign coal properties. The “Resource Links” at the end of this volume provide website links to guidance documents for preparing coal resource and reserve estimates in Australia, South Africa, and the USA.”This report discusses definitions, concepts and parameters used to determine coal resource and reserve quantities, and provides a framework to facilitate consistent categorization of coal quantities found within various depositional and tectonic regimes in Canada.Coal deposits, or portions thereof, are first categorized in terms of their geological complexity <Geology Type), and probable recovery method (Deposit Type). Methods for determining quantification parameters including seam thickness, areal extent and bulk density are outlined for each geology/deposit category. Within each geology/deposit category, coal resources are further divided, based on their assurance of existence, into measured, indicated, inferred and speculative subdivisions and, according to their feasibility of exploitation, into immediate and future interest subdivisions. Coal reserves within each geology/deposit category are subdivided according to whether they are within or outside active mining areas, and may be reported on in place, recoverable and saleable bases.A wide cross-section of the coal industry in Canada contributed to the development of this reporting system. To ensure that the parameters and concepts expressed in the system continue to reflect technological and economic realities in the future, the Coal Association of Canada has established a committee to facilitate periodic reviews."

Jan 1, 2003

"These guidelines, implemented in 2003, were recommended by the Diamond Exploration Best Practices Committee established by the Canadian Institute of Mining, Metallurgy and Petroleum. The guidelines are applicable to public companies and their consultants reporting diamond exploration results.“The guidelines are referenced in the Companion Policy of NI 43-101 with a statement that disclosure regarding the reporting of diamond exploration sampling results should conform to them.”Reporting GuidelinesThe following guidelines have been recommended by the Diamond Exploration Best Practices Committee established by the Canadian Institute of Mining, Metallurgy and Petroleum. These guidelines are applicable to public companies and their consultants reporting diamond exploration results.In respect of these guidelines, Diamond Exploration Results are results derived from the initial activities undertaken to investigate a diamond bearing prospect or deposit, to generate tonnage, grade and value estimates that cannot be classified as a Mineral Resource or Mineral Reserve. They do not address the earlier stage reporting of geophysical, geochemical or kimberlite indicator mineral results.Public reports of Diamond Exploration Results relating to mineralization not classified as Mineral Resource or Mineral Reserve must address the confidence limits of the result and contain sufficient information to allow a considered and balanced judgement of the significance of the results.The objective of these guidelines is to assist public companies and consultants in making appropriate disclosure of diamond exploration results by reporting in a manner which is:Uniform within the diamond exploration industry; Consistent with reporting from other industry sectors .Comprehensive .Unambiguous .The guidelines are not prescriptive. Materiality is the overriding principle that determines the information that should be disclosed. However, where a company or consultant deviates from the guidelines, the disclosure or technical report should state the extent to which the guidelines have not been followed, and the reasons for the deviation.The guidelines do not in any way replace jurisdictional reporting requirements (For example, the requirement for Canadian reporting issuers to comply with Canadian Securities Administrators National Instrument 43-101 by having technical disclosure endorsed by a Qualified Person as defined in that legislation)."

Jan 1, 2003

By Y. Long

The deep-hole surface blasting technique is a prime method of iron ore mining. Blasting fragmentation is one of the important economic indicators that measures the blast method to obtain the iron ore. To improve the efficiency of the blasting method and further reduce the cost of the subsequent processing of iron ore, this paper summarizes measured data gained from a certain amount of blasting test conducted in an iron ore mine in Guangdong province, China. According to the data analysis, there are differences on iron ore blasting fragmentation by different indicators of deep-hole blasting, such as decoupling coefficient of charge, contact state between charge and borehole wall, and change of detonation position in charge. These factors were compared in terms of relevance and impact. Research shows: under certain rock conditions, the decoupling coefficient of the charge has a best range related to blasting fragmentation. Since the detonation position in charge determines the direction of propagation of the explosion stress wave through ore and rock, bottom initiation and mid initiation will help to improve the iron ore blasting fragmentation in joints fractured rock and ore. The research conclusions have important application value for program design of iron ore surface blasting and to guide other types of rock surface blasting.

Aug 1, 2013

Unplanned open stope hanging wall dilution is a significant cost for many open stope mining operations. Significant advances in empirical and analytical approaches for estimating stope dilution have been made, however, many important factors are still either ignored or assessed in purely subjective terms. There are many hard to quantify factors that simultaneously influence opening stability and dilution. This creates a significant difficulty for determining the influence of a single variable, such as exposure time, on opening stability. Open stope exposure time has been found to be one of the important factors that influences overall stope stability and dilution. A study is currently being conducted to quantify many of the factors influencing open stope dilution. The assessment of a large comprehensive case history database of Hudson Bay Mining and Smelting Co. Ltd. (HBMS) operations forms the basis of this study. This paper presents the findings of a study on the influence of stope exposure time on open stope dilution. The study is based on applying existing empirical stope dilution prediction methods to the extensive HBMS database. Minimising stope mucking time has been recognised as a method to significantly reduce stope dilution. Factors which influence hanging wall dilution, such as drill and blasting methods as well as undercutting the hanging wall, have been applied to reduce the scatter in the database. Empirical design techniques based on rock classification attempt to relate opening stability to ?stand-up time?, however, these approaches have not frequently been applied to the mining industry. Data from a ?stand-up time? graph have been interpreted in terms of an equivalent average depth of hanging wall slough and compared to the HBMS database findings. To add to the existing HBMS database, several stope case histories have been taken from Geco mine. These cases include data from very large open stopes with long exposure times. Data from all three sources suggest that hanging wall slough increases between .14 and 0.3 metres per month for a rock mass Q? value between about 4 and 13.

May 1, 2003

By C. Zangerl, T. Strauhal, S. Perzlmeier, M. Holzmann

"In high mountainous regions, deep-seated rock slides are often observed in foliated metamorphic rocks such as paragneisses, micaschists and phyllites. Given that comprehensive investigations of deepseated rock slides are extraordinary costly and therefore are rare, most studies are related to investigations in the surroundings of infrastructures and human settlements. In the framework of this study there is an excellent opportunity to gain new insights in the fundamental processes and mechanisms of slowly moving deep-seated rock slides from a case study in the surrounding of a large dam reservoir in Austria. New fundamentals for comprehensive slope stability analyses and hazard assessments and sound prognoses focussing on the long-term stability and deformation behaviour of slopes under changing boundary conditions (e.g. impounding of a reservoir) and/or concepts for mitigation measures can be obtained. Within this contribution, geological field surveys, deformation monitoring, geophysical and drilling data were analysed and presented. Based on the compiled and analysed data, some key-properties of the rock slide will be presented, whereby special attention will be given on the geometry and internal structure, the slope kinematics, as well as hydrogeological and geomechanical aspects.INTRODUCTIONIn high mountainous regions, deep-seated rock slides are often encountered in highly foliated metamorphic rocks such as paragneisses, micaschists and phyllites (Agliardi et al. 2012). Critical situations may occur when deep-seated rock slides fail in a rapid manner characterised by very high sliding velocities, and/or when they develop into long run-out rock avalanches. However, many rock slides in foliated crystalline rock masses either do not move at high velocities nor do they accelerate seriously and form extremely rapid slides. Displacement rates in the range of a few millimetres or centimetres per year are common for this type of rock slide (Bonzanigo et al. 2007, Tentschert 1998, Watson et al. 2007). Nevertheless, some case studies show an activity behaviour characterised by acceleration phases reaching velocities of even metres per day. However a slope collapse is not expected and these slopes decelerate to much lower base activities. The trigger for these phases can be manifold and include heavy rainfall and snow melt, initial reservoir impounding and water level fluctuations, changes in the slope’s equilibrium state due to antecedent slow deformation processes, ongoing erosion processes along the toe of the slope, and others (Zangerl et al. 2010)."

Jan 1, 2015

By C. R. Lattanzi, M. J. Davie, L. D. Smith, J. R. Goode

"The feasibility study determines the technical and economic viability of a project at the level of accuracy required by the owner to make an investment decision. The economic analysis usually includes calculation of the discounted cash flow. Key components of the cash flow include the project capital cost, the operating costs, construction schedule, production rate, product prices and financial details.This paper examines the feasibility study for a typical mining project. The paper discusses acceptable methods for the determination of the geological and mineable are reserves. The prerequisites for the development of suitable designs, and the calculation of capital and operating costs for the mine, processing plant, and infrastructure are reviewed. Important features of the cash flow analysis and its interpretation are presented.IntroductionThe commercial development of a mineral deposit invariably requires the investment of capital in preparing the deposit for production. It has always been necessary, therefore, to demonstrate to the investor of capital that production of a saleable commodity is both technically feasible and economically viable. The instrument typically used to make these determinations is the feasibility study .Traditionally, mining companies have been rather conservative in their approach to financial management. Until about thirty years ago, the capital required to develop a new mine was most frequently provided by internal corporate cash now and virtually all of the necessary technical and economic studies were performed &apos;in house&apos;. Under these circumstances, there was little standardization as to what constituted an acceptable feasibility study, and even less as to what constituted an acceptable measure of economic viability."

Jan 1, 1991

By Brian Hart, Stamen Dimov, Aparup Chattopadhyay, Barun K. Gorain

"A novel gold deportment technique has been developed for complex copper-gold and double refractory gold ores using state-of-the-art technology. Characterization of these ores is a challenging task due to low copper and gold grades in ores, presence of both primary and secondary copper sulfide phases and variable proportion of visible and invisible gold in different sulfides and iron oxide phases.Double refractory ores are mainly composed of silicates and carbonates with moderate clay and mica, and minor amounts of sulfides and organic carbonaceous matter. Gold mostly occurs as ""invisible gold"" (sub-microscopic gold) as solid solution or as colloidal-sized particles in different sulfides and other phases. The dominance of invisible gold and presence of highly preg-robbing and finely disseminated carbonaceous matter adversely affects gold recovery in flotation and leach circuits. Characterization of this carbonaceous matter, commonly known as TCM and quantification of gold associated within TCM, along with different sulfide and oxide phases is highly complex and challenging.Studies were initiated on various complex ore deposits and also on samples representing various process streams. This paper presents the development of a systematic approach to diagnostic metallurgy using state-of-the-art optical and automated mineralogy techniques, namely, micro-probe, dynamic SIMS and TOF-SIMS analysis for quantification of invisible and visible precious metal content in various species. The relevance of the mineralogy characterization to metallurgy will also be discussed in this paper."

Jan 1, 2016

By P .. D. Vaillancourt, D. F. Sangster

Several occurrences of disseminated galena, including a former producing mine, are found in Pennsylvanian fluviatile sandstone of the Salmon River Basin, Cape Breton Island, Nova Scotia. Detailed study of the distribution of these occurrences has revealed that highest galena concentrations are found in sandstone overlying channel-shaped depressions in felsic basement rocks. These buried depressions, in turn, correlate in position with modern streams in areas of basement exposure. This correspondence suggests that the latter are at least partially controlled by an exhumed Pennsylvanian topography. If this is correct, then several other streams in the area, lying on basement, may be used to locate possible undiscovered lead deposits in sandstones of the Salmon River Basin.

Jan 1, 1990

By P. K. Kaiser, S. Maloney, S. Yazici

"This paper focusses on the strength or capacity of cable bolts and introduces a new perspective for cable bolt design by demonstrating that mining-induced stress changes may affect cables in a detrimental manner. The concept underlying a novel cable bolt pull-out resistanceor bond capacity model is described and its practical significance is demonstrated by application to a simple two dimensional scenario of a fall-of-ground.A number of practical implications emerging from the application of this model are discussed to provide guidance to ground control personnel jar improving cable bolt support systems in mining applications. These include cable layout optimization, use of cable pre-reinforcements, assessment of embedment length requirements, need for plated cables (or straps), use of bird-caged cables (or buttons), and grout quality issues.IntroductionDuring the last decade, cable bolting has become a standard support technique in mining for handling wide spans, reinforcing are passes, preventing or reducing dilution of ore in marginally stable stopes, and for many other rock support need s.In its infancy, many deficiencies in cable bolt supports resulted from improper installation techniques and, in particular, grout quality control problems and the use of empty breather tubes (Goris, 1990). The development of special grout pumps and fail proof placement procedures (Oliver, 1992; Bourchier and O&apos;Flaherty, 1992) have eliminated many of these early problems. Nevertheless, there are still situations where cables seem to lose their capacity during mining, and in these cases the cables do not provide the expected and needed ground support. In some instances, cables perform extremely well, whereas in others the same support layout and quality of support installation seem to be insufficient, allowing falls-of-ground or progressive cavings to occur."

Jan 1, 1992

By T. R. Eger

The Load-Haul-Dump (LHD) vehicle is a trackless, free-steered vehicle used in underground hardrock mining to move large quantities of ore/rock to haulage trucks, ore dump locations, or crushing stations. The purpose of this paper is to show, through case study examples, how principles of human factors can be applied to improve the overall design of the LHD vehicle to enhance line-of-sight (LOS), improve posture and decrease whole-body vibration exposure (WBV). Vehicle modifications (larger cab windows, lower engine profile, smaller buckets, angled radiator profile) can lead to improved line-of-sight. The use of secondary viewing devices, such as cameras, can also improve line-of-sight and allow the operator to adopt a more neutral sitting posture. Seating systems that are suited to the underground mining environment can result in vibration attenuation and less vibration transmitted to the LHD operator. The connection between vehicle design, line-of-sight and driving posture needs to be considered in order to continue to improve the design of the LHD and enable the operator to work in a neutral posture with minimal vibration exposure. Changes leading to improved line-of-sight, vibration reduction, and a neutral sitting posture will lead to fewer LOS related accidents and decreased risk factors for musculoskeletal injury.

Aug 1, 2013

By Cy Jordan, Ben Burdett, Adrian Dance, Jack Rainey

"In 1997, EIMCO Minerals installed a knowledge-based control system on one of the five primary grinding lines at Highland Valley Copper. The objective of the system is to maximise throughput without affecting circuit product size or flotation recovery. The system was commissioned in October 1997 on a SAG mill/ball mill circuit following a plant audit and upgrade of the control instrumentation.The system monitors and controls the SAG mill power, bearing pressure and recycle load by manipulating the solids feedrate, water addition and mill speed. The two ball mill and cyclone circuits are controlled through water addition at various points in the circuit as well as the number of operating cyclones.An on-line particle size analyser is used to measure the cyclone overflow quality. Models of the SAG mill charge level and overflow product size are also incorporated. A method of predicting the SAG mill power response to feedrate changes is used to lessen the effect of dead time for improved mill power control. In the future, inferred measurements of SAG feed particle size and hardness will allow changes in ore behaviour to be predicted and compensated for by the system.This paper describes the development of the project -from installation and commissioning to modifications and refinement -along with prospects for the future.BackgroundIn early 1997, EIMCO Minerals was contracted by Highland Valley Copper to install a knowledge-based or expert system control strategy on one of the five grinding lines in the mill. This was to become the start of the Advanced Control Project at Highland Valley Copper (HVC). This paper will review the progress of the Project as well as discuss the prospects for the future.Following a preliminary engineering study (or plant audit) by EIMCO in 1996, it was decided to implement an advanced control system in order to improve plant operations and increase productivity. The study suggested that such a system had a pay-back period of a few months through increased throughput without loss in flotation recovery. Highland Valley already had successfully applied higher level control through their Elsag Bailey distributed control system (DCS) and this was the next stage in process optimisation."

Jan 1, 1998

By A. B. Isaeva, A. Yu. Lein, A. A. Karpenko, V. V. Serova, A. P. Lisitzin, V. Yu. Rusakov, V. N. Lukashin

Abstract - The flux of sediment matter was determined using sediment traps near a black smoker ("Saracen’s Head," Broken Spur hydrothermal field) and the mineral and chemical compositions of the settled matter were examined. The metallic minerals are represented by Fe sulfides (pyrite and pyrrhotite), and Cu and Zn sulfides are also found in small and equal quantities. The hydrothermal suspended matter contains abiogenic calcite in amounts comparable to that in Ca sulfates. The content of silica and, specifically, of amorphous Si is unusually low. Such correlations between chemical elements and minerals, together with the isotopic compositions of S and C, are characteristic of a relatively young and active stage in the evolution of a hydrothermal system. Sediment traps within and under neutrally buoyant hydrothermal plumes collected biogenic material in addition to hydrothermal components. Microbial chemosynthetic production of organic carbon near the hydrothermal vent is comparable to primary production in the euphotic layer. Fe, Zn, Ca, Si, Ba and P are enriched in particulate matter in comparison to the background. A vast compound plume containing the discharge of multiple hydrothermal vents was found to the south of the Broken Spur hydrothermal field.

Jan 1, 1999

By Steve R. McCutcheon, Cees R. Van Staal, John P. Langton, Leslie R. Fyffe

The volcanic-dominated Tetagouche Group in northern New Brunswick contains numerous massive-sulfide deposits and intimately associated metalliferous sediments. The massive sulfides are generally hosted by Llanvirnian-Llandeilian volcaniclastic sedimentary rocks of the Nepisiguit Falls, Patrick Brook, and Boucher Brook formations. These formations are intercalated or closely associated with rhyolitic-dacitic flows and/or domes, and minor continental tholeiites of the Flat Landing Brook Formation. Pyroclastic rocks are relatively scarce in the silicic volcanic complex. Tuffites and epiclastic sandstones, of the Nepisiguit Falls and Patrick Brook formations, respectively, generally occur along the fringes of the silicic volcanic complex. The flows and tuffites are intruded by quartz- and feldspar-phyric rhyolite (porphyry) dykes, sills, and domes. Although the volume of the silicic volcanic complex is large, evidence for a previously proposed collapsed-caldera model is lacking. On the basis of host-rock type and stratigraphic position, the sediment-hosted massive sulfides have been divided into three groups: the Brunswick-, Caribou- and Halfmile Lake-type deposits. Syngenetic feeder pipes and asociated alteration zones are generally not present beneath the Caribou- and the Halfmile Lake-type deposits and, if present at all, are poorly developed underneath the Brunswick-type.

Jan 1, 1992

By S. Markstrom

The Boliden AITIK copper mine is located 100 kilometres north of the Arctic Circle in northern Sweden. A pre-feasibility study was conducted in 2005 with the aim of increasing the capacity of the existing processing plant. After analysis, options to upgrade the existing plant were abandoned in favour of building a new processing plant, with higher capacity and therefore greater profitability. A new plant could be designed with greater flexibility to make potential future expansions easier. A feasibility study for a new 36 Mt/y processing plant including fully AG grinding circuits and flotation was completed in 2006. The project was approved by the Boliden board shortly thereafter. Construction started in the beginning of 2007 and was completed during 2009. Commissioning of the new plant was undertaken in the first half of 2010. The grinding circuit consists of two lines with each line consisting of a 22.5 MW AG mill and a 10 MW Pebble mill in closed circuit with a spiral classifier. The nominal production level is 2 200 t/h for each grinding line. This paper presents the start-up and operation of the grinding circuit.

Jan 1, 2012

By G. Q. Liu

"The application of oxygen-enriched cyanidation to three Canadian gold ore samples has been investigated. The results showed that the use of oxygen can improve gold dissolution kinetics, reduce grinding time, and lower cyanide and lime consumptions. To obtain the same gold extraction, the required cyanide leaching time was reduced from 48 hours in slurry containing 8 ppm O2 to 12 - 24 hours in 20 ppm O2 slurry. Reagent consumptions were reduced by 23 - 37% for cyanide and by 35 - 54% for lime. There was little advantage to further increasing the dissolved oxygen to 32 ppm from 20 ppm. Gold extraction from the +200 mesh fraction improved 4 - 14% in oxygen-enriched slurry. A general kinetic model derived from the cyanidation of three ore samples can be described by the following equation: <equation>where E is the gold extraction (%) at time t (hours), EI is the ultimate gold extraction (%) , and &apos;P and k are constants depending on cyanide concentration, level of dissolved oxygen, and the characteristics of the ore samples. Comparative studies of conventional carbon adsorption and carbon adsorption in oxygen-enriched slurry have also demonstrated that oxygen enrichment resulted in more favourable conditions for gold adsorption."

Jan 1, 1995

By H. Tokuichi, H. Ohta, K. Sato

A physical separation technique of tantalum capacitors from waste print circuit boards is in a development phase in Japan. A tantalum capacitor consists of an exterior coating of resin (epoxy resin) mixed with silica fillers and a sintered tantalum compact, the latter of which is impregnated with manganese dioxide (MnO2). In this study, we developed a process to recover tantalum oxide from tantalum capacitors by roasting, fluidized-bed separation, and hydrometallurgical treatments. Our aim was to recover tantalum oxide with high purity from waste tantalum capacitors. In this process, the exterior resin was selectively decomposed by roasting without oxidation and pulverization of the sintered tantalum compact at a proper temperature. Furthermore, the decomposed resin with silica filler on the surface of the sintered tantalum compact was mostly removed by fluidized-bed separation. The surface of the sintered tantalum compact was cleaned by ultrasonic irradiation in an acid solution to remove the MnO2 paste as well as residual Ag paste and silica filler. The impregnated MnO2 in the sintered tantalum compact was leached as Mn(II) ions using acid solutions via the reducing effect of tantalum metal to recover purified tantalum oxide.

Jan 1, 2014

By Kevin Bell

About Beltek Inc. For more than a decade Beltek, Inc. has been working with national and international organizations to harness and deliver solutions which gain real ebusiness advantages in today&apos;s world. Our objectives are to partner with our customers to achieve maximum results, while reducing costs. At Beltek, we provide a commitment to you and your organization&apos;s needs. Whether that be delivered by ensuring our services and products are state of the art or by providing a level of personalized service, which makes you feel like the center of attention, Beltek is about adding value to every job we work on. The individuals who work at Beltek quickly become your friends because we share your passion and enthusiasm for the business we are in. That&apos;s why every person is a leader in his or her respective fields. Having these individuals as apart of our business ensures you get the best out of our equipment, receive the very latest in advise, problem solving and support. We also pride ourselves on our ability to remain flexible at all times because we know deadlines and schedules can change quickly, so we always go the extra mile to deliver exactly what you need.

May 1, 2004