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By Claudio Rocha Rosales

"Peñoles is a mining group with integrated operations for the smelting and refining of non-ferrous metals, and it is also a chemicals producer. Peñoles is the world’s foremost producer of refined silver, metallic bismuth and sodium sulphate. It is also the leading Latin American producer of refined gold, lead and zinc. The Met-Mex Peñoles Zinc Plant commenced operations in 1973 with an annual production capacity of 105,000 t/y zinc. Since then, production capacity has increased, and at present, it stands at 240,000 t/y zinc. In this paper, the leaching process and particularly the operation of the jarosite circuit is reviewed, specifying process improvements to treat high iron calcines.INTRODUCTIONTwenty years ago the Electrolytic Zinc Plant in Peñoles was treating high quality zinc concentrates with low concentrations of iron (~7.5 wt.%) and silica (1.8 wt.%). Nowadays the quality of zinc concentrates is poor with a typical iron content of around 11 wt.% and silica at 2.0 wt.%. This has created numerous processing problems in our roast-leach-purification- electrolysis sections. In order to meet customer requirements it is necessary to find processing solutions to assure the operational continuity of the plant. These processing solutions are the focal point of this paper.REVIEW OF THE LEACHING PROCESSThe purpose of the leaching process is to recover the metals, mainly zinc, through a series of extraction stages with sulphuric acid solutions, which progressively increases the zinc dissolution. After the series of acidification stages, the solution, which is rich in iron, is sent to the jarosite circuit to separate zinc from iron (Garcia & Valdez, 1996). The first step of the leaching process is the neutral leach circuit which produces a zinc sulphate solution that is sent to the purification section for the removal of impurities such as cadmium, cobalt and copper. Then this solution is sent to the tank house to feed the electrolytic cells."

Jan 1, 2016

By R. D. Brown

For the first time in years, the spring budgets of federal and provincial governments have not brought down major new proposals affecting the tax burdens of the mining industry in Canada. It seems appropriate to use this unaccustomed period of tranquility to set out an extremely abbreviated summary of the principal features of the federal and provincial income and mining tax rules affecting the mining industry.

Jan 1, 1977

By Derek Apela, Coralee Heske, Bunyamin Kahraman, Muhammad Adi

Effective blast fragmentation is essential in underground mining, as it directly influences downstream processing efficiency and operational expenses. This study investigates the application of Non-Newtonian Fluids (NNF) as stemming materials, presenting a novel method to enhance energy confinement, minimize environmental impact, and optimize blast performance. NNFs exhibit shear-thickening behaviour, enabling them to transition between fluid-like and solid-like states under stress, which renders them suitable for regulating explosive gas ejection during blasting. Field trials were performed by Vale Base Metals in Thompson, Manitoba, in their underground nickel mine to evaluate conventional slag stemming against NNF-based stemming in production-scale blasts. Emulsion explosives were employed, and blast performance was assessed through velocity of detonation (VOD) measurements, vibration monitoring, and AI-assisted fragmentation analysis using WipFrag. Preliminary results indicate that NNF stemming improves fragmentation, resulting in a reduction of D50 by as much as 38%, enhances energy confinement, and may decrease the incidence of hole plugging and re-drilling in subsequent blasts. This study presents an alternative to conventional stemming methods, highlighting potential advantages for enhanced safety, efficiency, and sustainability in blasting operations. Additional research and field trials are necessary to improve implementation protocols and facilitate the widespread adoption of this unique method in the mining sector.

May 4, 2025

By Denis Raymond, Yvon Trudeau

"Abstract-The Orion gold mine, located 7 km northeast of the town of Malartic, Quebec, was discovered in mid-1985. Underground exploration was undertaken in 1986Ieading to commercial production in 1988. The upper part of the orebody was exploited above the 125 m level and a total of 131 090 t at an average grade of 5.31 g/t gold were extracted.This paper describes the authors' current knowledge and interpretation of the geology, gold distribution, and structure of the Orion No. 8 ore zone deposit. The deposit is an epigenetic lode gold occurrence somewhat unique in that both quartz-vein type and pyritic type of gold ore occur side-by-side. It is located within the Marban-Norlartic Deformation Corridor (MNDC) formed during a first deformation stage (D1). The MNDC is a well-defined regional structural feature in the Val d'Or- Malartic mining camp. Primary gold mineralization is associated with the D1 event and is represented by pyritized , silicified and brecciated basaltic lavas enclosed by ultramafic flow units. The ore zone is concordant with the MNDC. Felsic intrusions are spatially related with the ore zone, but their role in the genesis of the ore has yet to be defined.A second deformation event (D2) resulted in local folding, a second schistosity (S2) and reverse faulting. Gold remobilization, the formation of the gold-bearing quartz breccia and the emplacement of the main quartz vein at the No . 8 zone deposit were associated with this event."

Jan 1, 1992

By G. M. Castillo

Newmont?s Phoenix mine started production in March of 2006. Due to the extreme hardness of the ore, the mill has struggled to meet throughput projections. Grinding studies showed that optimizing the existing circuit would not achieve budgeted throughput. These studies also showed that the pebble crusher was being underutilized due to the inability of the SAG mill to break the rock. The concept was developed to supplement the feed to the existing pebble crusher with a secondary crusher. Models of this process looked favorable so a portable crusher was installed to test the process. The temporary crusher was successful at increasing the throughput by 7% and based on the operating data, plans are currently being developed to install a permanent secondary crushing system in front of the SAG mill. This paper will review the results from the test crusher and the flow sheet for the permanent secondary crusher.

Jan 1, 2012

By Chri Langille, Dougal McCreath, Samantha Espley

"In 1993, trials of two innovative applications of liner support involving the replacement of bolts in the ground support system were undertaken at Inco mines. The first trial involved an evaluation of the effect of dynamic loading on mesh-reinforced boltless shotcrete in a sub-level cave mining area on 2400 level at Stobie Mine. The second trial involved an evaluation of the MIROC Mineguard spray-on liner as a replacement for bolts and screen support, or as a replacement for screen support alone, in a topsoil heading of a bulk, VRM (vertical retreat mining) stope on 3240 level at Lower Coleman Mine.In the Stobie Mine trial, an uppers retreat heading was supported using a two-pass system. First, shotcrete was applied 2 inches thick, followed by pinning of mesh screen to the back and walls. A second pass of another 2 inches of shotcrete was then performed. For recovery of the ore zone, a vertical slot was created using a Borepak blind boring machine. The uppers rings were blasted, one or two rings at a time, starting at the slot and retreating out of the heading. During blasting of the production rings, blast monitoring was used to record the ppvs (peak particle velocities). For a series of 5-ring blasts, the maximum ppvs were measured to be 0.4 m/s (16 in./s) with a maximum charge weight per delay of357 kg (800 Ib). Six 5-point convergence measurement stations were set up and after each blast the total rockmass convergence was measured using a tape extensometer. Although a maximum displacement of 100 mm (4 in.) was measured, the shotcrete still managed to provide some support junction. A support damage assessment was also done to try and relate blast vibration to effectiveness of the mesh reinforced shotcrete liner. This trial demonstrated the effect that blasting has, on a support system, and it also demonstrated the necessity of having the mesh reinforcement properly placed within the shotcrete."

Jan 1, 1995

By G. S. Barry

INVESTIGATIONS to date have shown that, should there be the need or the appropriate economic stimulus, Canada's mineral resources are sufficiently extensive to allow considerable expansion of its non-fuel mineral industry, during the remaining part of this century and possibly beyond (1, 2). The availability of sufficient capital will be one of the critical factors which will determine whether this potential will be fulfilled. The following analysis centers on the capital requirements of the Canadian non-fuel mineral industry under one set of basic assumptions of capacity growth, cost of new and replacement capacity, rates of depletion and depreciation of mines and plant, and the cost of exploration and infrastructure. Mindful of the fact that exploration and development will not thrive in Canada unless a very positive approach is taken, the writers make no apologies for being "optimistic" about long-term production prospects. Furthermore, in the event that world demand does escalate as anticipated and the forecast realistically attainable levels of Canadian production are not reached, then Canada will not have reaped the full range of economic benefits available, and opportunities will have been lost. Projections for Canadian production between 1976 and 2000 are essentially based on the forecast published in the 1974 paper, "Towards a Mineral Policy for Canada - Opportunities for Choice (3), with some updating on the basis of recent developments.

Jan 1, 1977

By G. W. Harris, P. Mousset-Jones, J. Daemen

"To minimize ore dilution induced by blast movement in surface mines, it is necessary to quantify such movement. This will enable more accurate location of the grade boundaries beneath the surface of a blasted rock pile before excavation. A method has been developed and tested to accurately measure the direction and magnitude of subsurface blast movement. This technique uses a cesium vapour gradiometer and a real-time, differentially corrected GPS system to locate pre- and post-blast position of magnetically enhanced target objects placed within blastholes inside a bench. The procedure developed does not require the blasted rock to be disturbed, and the movement information is available within a sufficient time to allow for modification of the selective mining boundaries for each surveyed blast. It was found that the maximum depth of target detection was 18 m, with the overall accuracy being measured as ±1 m (horizontally) and ± 1.2 m (vertically). IntroductionOre dilution is a critical concern for many mining operations. In some instances, it may be the cause of considerable mineral loss. Where the mineralization is finely grained, sedimentary and disseminated in nature, and exhibits no clearly defined visual ore/waste boundary, there is a heightened possibility for ore grade dilution. In most modern open pit gold mines, it is economically desirable to minimize dilution in the production process through the practice of selective mining by defining pre-blast ore digging boundaries, called digging polygons, on the preblast bench area. The polygons’ positions are defined by sampling the production drill holes, with the resultant assay and survey data being used to estimate the areas of specified grade content within the bench. Once the ore is blasted in the bench, the pre-blast locations of these digging polygons are flagged as designated areas on the broken ore pile. The purpose is for the loader operator to be able to recognize which areas of blasted rock are to be sent to the appropriate processing facility or to the waste dump."

Jan 1, 2001

By T. A. Chepushtanova, I. U. Motovilov, V. A. Luganov, G. D. Guseynova

"Kazakhstan has significant reserves of oxidized nickel ore with low nickel content. Processing of such ores is effective via pyrometallurgical technologies such as smelting to ferronickel or matte with consecutive extraction of metals from melting products. There are also many options for direct hydrometallurgical processing. However, they do not provide high nickel recovery.We studied extraction of nickel and cobalt by using combined technology of low-grade ore processing from the Shevchenko Kazakhstan deposit, which includes smelting to poor matte followed by hydrometallurgical processing of the matte. The nickel content in the initial ore was 0.75–0.9%. Pyrite concentrate of Sokolov-Sarybai Kazakhstan deposit containing 0.17% cobalt and 0.06% nickel had been used as a sulphidizer at smelting.As a result of the study, we were able to extract up to 98% of the nickel and up to 80% of the available cobalt. Obtained matte contained 3.1% nickel, 0.29% cobalt, 71.6% iron and 24.3% sulfur. Matte leaching was carried out by hydrochloric acid. The iron content in the pregnant solution was 170–185 g/dm3. Nickel and cobalt precipitation from the pregnant solution was carried out by hydrogen sulfide. Initial matte or cast iron was used as neutralizers during the process. Practically complete precipitation of nickel was achieved at 3–5% excess of neutralizer at 333–343°K in 4 hours; up to 95% of cobalt precipitation was achieved in 50% excess of neutralizer at 363°K in 8 hours. The purified solution contained 200–600 mg/dm3 of nickel, 80-100 mg/dm3of cobalt and 175–185 g/dm3 of iron. The purified solution allows to obtain iron oxides by high-temperature hydrolysis, and to regenerate hydrochloric acid.As a result of non-ferrous metals precipitation we obtained sulfide concentrate with concentration of Ni up to 25% and concentration of Co up to 5.5%. The technology is recommended for semi-industrial testing."

Jan 1, 2016

By R. A. Halet

"The Malartic Gold Fields mine is a good example of the association of ore deposits with a major fault zone. It also exemplifies the control exerted by the physical and chemical character of the host rocks on the localization of orebodies.The mine is in Fourniere and Dubuisson townships, Abitibi county. It is 6 miles east of the town of Malartic, 9n the main highway and railway from Noranda to Val d'Or.The discovery of the mine is due largely to the enterprise of the late J. P. Norrie, who organized the present Company in 1935. The ground is entirely covered by overburden, but Mr. Norrie believed that the extension of the Cadillac-Malartic 'break', the principal ore-bearing structure of the district, would be found on this group of claims. This belief was supported by the discovery of gold-bearing float in the area, and was confirmed by a dip-needle survey and a few pilot diamond drill holes that showed that the favourable Malartic greenstone band passes through the centre of the property.In this way the most favourable area for prospecting was narrowed to a zone 2 ½ miles long by ½ mile wide underlain' by greenstone. The remainder of the property is underlain by sedimentary rocks, which, from experience elsewhere in the camp, were not considered as promising. However, as the entire surface is covered by deep overburden, the location of orebodies even within this more or less restricted area could be accomplished only by a long campaign of diamond drilling. Systematic diamond drilling began in 1936.The contacts of the greenstone band were considered to be the most promising places to begin the work, and the early drilling was concentrated on the south contact, because the orebody of the East Malartic mine, 4 miles to the west, had been discovered on this structure and it was reasonable to hope for a repetition of these conditions. Although the south contact was very thoroughly explored, with a certain amount of encouragement, the work did not prove the existence of deposits of ore grade, and attention was shifted to the north contact zone of the greenstone band. In this locality much more promising results were obtained, and a number of good orebodies were outlined."

Jan 1, 1954

By N. Ahern, D. B. Dreisinger, G. Van Weert

In the thiosulfate leaching of gold, degradation of the thiosulfate reagent is a major cost. One of the intermediary degradation products is trithionate, which also inhibits gold recovery from solution by ion exchange. Little attention has been given to this species in the context of gold leaching - the limited information on trithionate and its solution chemistry available in the literature is seldom directly related to gold leaching conditions. This review is a compilation of the published knowledge on trithionate, with a specific focus on identifying the relevance of this information to gold leaching and the shortcomings in the knowledge base.

Jan 1, 2005

By Alan B. Morrow, William A. Poe

"Minerals processing operations are constantly challenged with improving production rates, yields, energy efficiency and process stability. Advanced Process Control has proven to be an effective tool for improving operations by capturing the full process capabilities consistently. However, the velocity of applying the technology as well as the sustainment of these significant benefits has been hampered by the usability of the software and adaptability of the applications.Some of the new technology developments that improve the usability and adaptability of advanced process control include:• modern and intuitive user interfaces,• customizable models to support unique process behavior,• fast and flexible OPC connection tools,• automated model building,• integration with first principles dynamic models and• improved performance monitoring.This paper will briefly discuss the new technology developments that have improved the usability and adaptability of advanced process control and how this can affect minerals processing operations.In today’s environment, Minerals Processing plant managers continuously face new challenges and requirements including:• higher energy efficiency,• increased run lengths,• reduced product quality variability,• reduced emissions,• higher availability, and• lower operating costsOperating a unit to meet these challenges in real time is not easy for operators and conventional process control systems. However, innovatively using existing technologies in Minerals Processing plants can improve operations on a minute by minute basis and reap significant benefits.Advanced Process Control (APC) can extract the maximum performance benefits from existing equipment while respecting plant operating constraints. Expensive capital projects to upgrade equipment are not always necessary. Advanced Process Control can deliver significant economic benefits by maintaining the plant at its most profitable point as conditions change."

Jan 1, 2016

By Jodi Wilding, Barry Lurnsden

The implementation of new technology to mineral separation operations requires rigorous testing to confirm the technology&apos;s technical and economic benefit. The Jaguar Mine owned by Jabiru Metals is located in Western Australia and sequentially separates a copper concentrate and then a zinc concentrate. Fine grinding (80% of zinc in tail is <25µm) is required to achieve efficient mineral separation. All mineral losses are therefore fine mineral losses, and so improvements in metal recovery must focus on this fine mineral. Magnetic aggregation technology has been shown to increase the recovery of fine paramagnetic minerals so it was an appropriate technology to evaluate at Jaguar. Testwork commenced in the copper circuit and it was found that there was a substantial reduction in copper in copper tail and an increase in zinc recovery to the zinc concentrate. The increase in zinc recovery in the latter zinc circuit was an interesting result and initiated the second stage of testwork that was to install and test a second magnetic conditioning unit in the zinc círcuit. This showed a further increase in zinc recovery. Magnetic conditioning technology has now been fully evaluated in the plant and is now part of the Jaguar flowsheet.

Jan 1, 2011

By H. J. McQueen

Pressure welding is a solid state joining technique that depends on bringing the parts into sufficiently close contact that inter-atomic bonds are achieved. Pressing is more effective at elevated temperatures where plastic flow causes the asperities to collapse; improved application conditions are derived from hot-work research to clarify temperature and strain rate dependence of hot strength and ductility. The substructure evolution systematically studied in hot working to determine dynamic recovery or recrystallization is applied to clarifying that developed in welding. The various processes are affected differently by work-piece geometry and final shape requirements. In addition to pre-cleaning of the surfaces, the plastic flow helps disperse the remaining oxide layers as was originally exemplified in blacksmith hot forging of layered sword blades and in bellldie welding of wrought iron tubes. The presentation critically compares the utility for various materials and configurations of simple pressure, ultrasonic application, diffusion, explosive, rotary and linear friction and friction-stir processes. Diffusion bonding (primarily Ti) with light cleaning, low pressure, little distortion in protective furnace atmosphere contrasts strongly with the heavy upsetting in friction welding, or complex alloy mingling and substructure variations in friction stir joints.

Jan 1, 2011

By Yvon Trudeau, Deni Raymond

"The Orion gold mine, located 7 Ian northeast of the town of Malartic, Quebec, was discovered in mid-1985. Underground exploration was undertaken in 1986 leading to commercial production in 1988. The upper part of the orebody was exploited above the 125 m level and a total of 131 090 t at an average grade of 5.31 g/t gold were extracted.This paper describes the authors&apos; current knowledge and interpretation of the geology, gold distribution, and structure of the Orion No.8 ore zone deposit. The deposit is an epigenetic lode gold occurrence somewhat unique in that both quartz-vein type and pyritic type of gold ore occur side-by-side. It is located within the Marban-Noriartic Deformation Corridor (MNDC) formed during a first deformation stage (D1) The MNDC is a well-defined regional structural feature in the Val d&apos;Or - Malartic mining camp. Primary gold mineralization is associated with the D1 event and is represented by pyritized, silicified and brecciated basaltic lavas enclosed by ultramafic flow units. The ore zone is concordant with the MNDC. Felsic intrusions are spatially related with the ore zone, but their role in the genesis of the ore has yet to be dermed.A second deformation event (D2) resulted in local folding, a second schistosity (S2) and reverse faulting. Gold remobilization, the formation of the gold-bearing quartz breccia and the emplacement of the main quartz vein at the No. 8 zone deposit were associated with this event."

Jan 1, 1992

By D. Sanguinetti, A. Consigny, M. Nodwell

"Alkali precipitation of dissolved metals is an inexpensive but non-selective means of treating mine wastewater. Alternatively, sulphide precipitation can treat to below parts-per-million concentrations while selectively recovering valuable metals. While technically feasible, sulphide treatment of dilute waste streams increases the size and cost of the plant relative to the metals loading. Ion exchange has been applied at two separate sites to pre-concentrate nickel containing wastewater prior to recovery in smaller and more cost effective sulphide precipitation circuits. The result is a dual-circuit system that can maintain high selectivity and reduce overall facility cost while meeting strict effluent regulations.INTRODUCTIONAlkali precipitation using lime is the most common method of treating mining effluents for dissolved metals removal. This method is generally sufficient for waste streams containing mixed metals of little value, and for meeting modest metal concentration limits in the final effluent. Due to the non-selective nature of the lime process, the produced metal hydroxide sludge is of little value. All metals are removed together in a sludge product which cannot be re-processed for further value recovery.By contrast, sulphide precipitation can be used to selectively remove and recover valuable base metals (such as copper, zinc, nickel and cobalt), since the sulphide will preferentially target these metals without reacting with less valuable metals (such as iron and aluminum). The low solubility of the metal sulphide solids also supports the removal of base metals to lower concentrations than can be achieved with alkali precipitation in addition to other benefits discussed more fully in a prior paper (Bratty, Lawrence, Kratochvil & Marchant, 2006). The corollary to this solubility feature is that sulphide precipitation can function on influent streams containing low (< 10 mg/L) metals concentrations to meet very low parts-perbillion final effluent concentrations. Reagent overdosing is also minimized when compared to alkali precipitation."

Jan 1, 2012

By Paul Girard

"The copper property of Madeleine Mines Ltd. is in Lapotardiere and Boisbuisson townships, Gaspe North. The initial find was made in 1964, and subsequently a copper deposit of 5.3 million tons of ore was outlined. The property lies in Ordovician sedimentary and volcanic rocks near the major granite intrusive of the McGerrigle Range. The host-rock is a 300-foot-thick metamorphosed silty shale unit, close to the contact of the intrusive. The structure itself coµsists of a southerly-dipping monocline or the south limb of an anticline, on which a large dragfold has been imposed.Chalcopyrite, bornite and chalcocite are the principal sulphides present in the ore. Of particular interest is the zoning arrangement of these sulphides. The orebody is chimney-like in shape and appears to be a fracture-filling deposit that is genetically related to the granite intrusive and is confined within a highly fractured zone of very brittle rock. The deposit presents features uncommon to any of the other known copper deposits in the Gaspe Peninsula."

Jan 1, 1969

"Sink-float analysis is often used to obtain yield-ash and density partition curves in the coal industry. These provide a valuable tool for evaluating the performance of a separation process. However, for dense minerals, obtaining complete grade-recovery and density partition curves is more difficult due to the lack of heavy liquids available with the required densities. This paper examines a potential solution to this problem which is to perform batch fractionation of mineral samples in a laboratory-scale REFLUX™ Classifier using high viscosity fluidising liquids. The REFLUX™ Classifier is a gravity separation unit consisting of a system of parallel inclined channels positioned above a vertical fluidised bed. Operated in semi-batch mode, a charge of particles is fluidised from below and particles up to a certain density are elutriated from the top of the system. The fluidisation rate is then increased incrementally to fractionate the sample at progressively increasing densities. Previous work by Hunter et al. (2014) and Iveson et al. (2015) has shown that this method provides excellent agreement with yield-ash and partition curves for coal, especially when glycerol solutions are used as the fluidising liquid. This approach has now been extended to obtain the grade-recovery and density partition curves of high density mineral samples. This method has the potential to provide the minerals industry with an effective tool to evaluate the performance of unit operations separating at cut points higher than the available heavy liquids.INTRODUCTIONMeasuring efficiency and effectiveness is of key importance in the continuous improvement of mineral processing plants. For density based separation, one way the performance of a process can be evaluated is the measurement of density-based partition curves. Currently, this is done in the coal industry using the sink-float method, where heavy liquids are used to fractionate particles into discrete density intervals. However, with high density minerals such as iron ore, liquids of sufficient density are rare, and in most cases also pose serious health and safety concerns to laboratory operators. Most commercial laboratories do not perform sink-float separations above a density of about 4400 kg/m3, the maximum density of Clerici solution without operating at excessive temperatures (Koroznikova, Klutke, McKnight & Hall, 2007; Rosenblum, 1974)."

Jan 1, 2016

By J. M. Skeaff

"The main solution, ore and residue pulp streams in the Rio Algom Quirke I uranium mill at Elliot Lake have been sampled and analyzed for radium-226. Analysis of the ore and leached residues indicates that Ra-226 dissolves and precipitates within the first pachuca tank. A maximum of approximately 0.2% of the Ra-226 in the ore remains in solution during leaching.IntroductionConcern over the acid drainage and radionuclide dissolution problems associated with uranium tailings disposal sites in Canada has prompted investigation into methods for improving current uranium processing practice.Present commercial practice usually involves leaching of the uranium ore with sulphuric acid, ion-exchange separation of the uranyl sulphate complex from the leach liquor and"" precipitation of the uranium as yellowcake. Daughter products of U-238, such as Th-230, Pb-21O and Ra-226 remain with the tailings and undergo long-term dissolution.Table I summarizes the probable behaviour of the radionuclides during milling. The concern here is with Ra-226, because it will deposit in the bones if ingested and is ""thus considered a serious health hazard(1), Similarly, Po-218 and Bi-214, which are daughter products of Rn-222, can be retained in the lungs and are considered to be the principal sources of radiation dosage(2) arising from the inhalation of Rn-222. Previous investigations(3-9l indicate or imply that Ra-226 undergoes redistribution during milling. However, detailed published information on the behaviour of Ra-226 in the uranium milling process appears to be lacking. A knowledge of the behaviour of Ra-226 in uranium mills, particularly during leaching, could lead to improved methods for its control.This paper reports the occurrence of Ra-226 in the Rio Algom mill. The main objectives of the study were to determine (1) the distribution of Ra-226 within the solids, (2) at what point, and how rapidly, redistribution occurs and (3) whether there are high concentrations of Ra-226 in solution."

Jan 1, 1981

By P. Abachi

Cemented carbides or hard metals that generally consist of hard tungsten carbide and a tough metal binder such as cobalt are important in many segments of the world economy, ranging from automobile related components to machining, cutting, and drilling tools. For metal cutting operations such as turning and milling, replaceable cemented carbide inserts are frequently used. The exposure of inserts to very severe conditions (e.g. temperatures as high as 1000°C) in combination with very high loads, limits their lifetime. When the tools and components are scrapped, they are collected with a view to recovering the tungsten carbide and cobalt due to both their environmental aspects and their strategic importance. In this work, a selective electrolysis process was used for recovery of WC powder particles from cemented carbide scraps. The WC-10Co and WC-10Co-VC up to 3 wt.% VC was produced using powder metallurgy route. The mean particle size of WC, Co and VC were selected as 2.5, l.5 and 2.2 µm respectively. Referring to electrochemical curves of WC-10Co cemented carbides in hydrochloric acid solutions with different concentrations, the recovery rate was enhanced in IN acid. Therefore, this solution was selected for recycling of all samples. The surfaces of as-produced and corroded specimens were investigated using a scanning electron microscopy (SEM). Detection of corrosion products was provided by energy dispersive spectrometry (EDS). According to results, the selective electrolysis process could be useful in the recycling of scrap carbide materials, although more studies should be undertaken on economical aspects of the process and the quality of samples produced using recovered powders.

Jan 1, 2005