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By A Sadough Vanini

In this paper large deformation of smart functionally graded beams with initial imperfection and under thermal loadings is considered. Smart beam consist of two types of layers. One layer is made from functionally graded materials and a layer or a set of layers from active materials that usually is made from piezoelectric materials that are bounded on the surfaces of beam. An active controller is used for controlling the deformation and stress in functionally graded layer of beam. A simple Euler- Bernoulli beam theory is used for analyzing of beam. In functionally graded layer the material property vary continuously through the thickness direction and power law model is used for the variation of elastic modulus, heat expansion and heat conduction coefficients. Poisson ratio is assumed to be constant in functionally graded layer. The effects of varying the power law constants and the Gain of controller is considered here. The results are reduced and compared with smart functionally graded beam without initial imperfections.

Oct 1, 2011

By W. S. (Steve) Vaughan

The Origins of Joint Ventures in Canada?s Mining Industry ? Among the most important financing structures used in our mineral industry today ? Virtually unheard of in the Canadian industry prior to the 1970s ? Borrowed from the U.S. oil and gas sector where it came into prominence in the late 1930s ? The Securities Acts of 1933 and 1934 in effect killed the sale of (equity) shares for financing oil and gas wells and start up mining companies

May 1, 2013

By H. Rafiei Renani, C. D. Martin

"The Cohesion Weakening Friction Strengthening (CWFS) is adopted in numerical analysis to capture the observed progressive failure of hard rock pillars. As a case study, pillars at the Elliot Lake mines with width to height ratios of 0.5 to 3 were analyzed in FLAC3D. Pillars with width to height ratios of 0.5 and 1 show a very similar strain softening behavior while with width to height ratios of 2 and especially 3 indicated prolonged strain hardening. The CWFS model successfully captured the mechanism of progressive failure observed in hard rock pillars including initiation of spalling at the corners, progress of spalling towards the centre and formation of hour-glass shaped pillar, and eventually shearing through the width of pillar. Both the CWFS model and site specific empirical formula successfully separated the stable and failed cases in the Elliot Lake mines. While both models are in reasonable agreement for width to height ratios of less than 2, the empirical formula gives increasingly lower strength values for wider pillars which may result in excessively conservative and uneconomical design.INTRODUCTIONPillars are the portion of in situ rock left between the adjacent openings to maintain the stability of excavations. Conditions of equilibrium require that the loads previously carried by the excavated rocks be transferred to the pillars resulting in elevated stresses within the pillar. Hence, prediction of the behavior of pillars under these loads is important for underground design. Determination of the strength of pillars is a classic subject in underground mining. In conventional mining methods such as room and pillar operations, economic incentives point towards higher excavation ratios i.e., leaving smaller pillars between the mined excavations, while safety and stability requirements favor wider stronger pillars. In some mining methods such as caving operations, the problem is even more challenging. On one hand, the whole operation is directly dependent on the proper continuous flow of caved ore between the drawpoints which requires optimizing the spacing between drawpoints and thereby often leaving narrower pillars. On the other hand, the pillars should be wide enough to ensure the safety of mining operation. Both the blockage of drawpoints as a result of wide pillars and uncontrolled failure of narrow pillars can jeopardize the investments and mining operation.Therefore, design of pillar poses a somewhat unique challenge to rock engineers where simple conservative approaches frequently used in other design methods are no longer acceptable. The behavior of pillar under elevated loads should be predicted accurately."

Jan 1, 2015

By J. Starkey

A comminution circuit in recent history, is one of the most difficult parts of a mineral processing plant to design with confidence. It is usually the most costly part of a plant to build, and it can consume up to half or more of the energy used on a mine site. To suggest that comminution energy usage is sustainable in the long term is not possible at this time. What we have to choose from today, based on more than 50 years of experience, does include the best available technology, and the best way to design it. There is controversy in the industry as to how to properly approach the subject of comminution design, with many of the optional solutions requiring a level of training and expertise beyond the ability of a non-specialist engineer. Semi-autogenous grinding technology in particular, has not been properly appreciated because of many recent mistakes in its application and design, which have blurred the positive perception about what SAG technology is, how it can be used, and how it needs to be designed and built. In order to change this, mine owners and senior managers need to take responsibility for, and learn to understand the fundamental challenges that a comminution circuit poses to the project, to the design process, to the operators who use the equipment, and to the resulting metallurgy. This address is intended to summarize these challenges and offer fundamental engineering solutions, which are clear, specific and in a format which is directly applicable to the mining and mineral engineering community.

Jan 1, 2018

By D. Yamada, T. Tanaka, N. Inouchi, J. Nakahigashi, H. Yoshimura, T. Nonishi

The use of cereal food materials as lubricants was investigated in an attempt to develop nonpolluting lubricants. Suspensions of wheat flour in water and other types of cereal food lubricants were prepared and their friction coefficients measured. The results indicate that a cereal food lubricant containing 30% lipids, 2% proteins, 60% carbohydrates and 0.6% calcium carbonates has the lowest friction coefficient for a sheet (cpTi-1). As example applications, the lubricant was tested with a forming press and a screw-fastening device. In both applications the cereal food lubricant performed relatively well in comparison to conventional lubricants and thereby has potential for practical applications.

Jan 1, 2006

By C. Barlow

The White Mesa Mill (WMM) began operating in 1980 as a regional processing mill owned by Energy Fuels Nuclear, Inc. Original mill design was for 656,000 Mtpa of U ore producing 1,250 tpa of U3O8 concentrate. Sustained market downturns delayed facility upgrades during most of the 1980s and 1990s. The new owners of WMM, Denison Mines, elected to advance the regional mill concept in 2007 with the modernization of these facilities. This paper details decisions taken and lessons learned in plant redesign, choice of leading-edge instrumentation, motor controls and process automation, training and some example benefits from process control stabilization.

Aug 1, 2010

By G. D. Bysouth, G. Y. Wong

"The Endako molybdenum deposit is located 160 km west of Prince George, British Columbia. It occurs within the main body of the Francois Lake Intrusions, a composite batholith consisting of early, middle and late intrusive phases. The ore deposit is confined to Endako Quartz Monzonite, a middle phase intrusion, which is bound on the north by Carey Alaskite and on the south by Francois Granite, both late stage intrusions. In the mine aretz, the Endako Quartz Monzonite has been intruded by pre-ore dikes of quartzfeldspar porphyry and porphyritic granite, and by post-ore dikesof basalt.The Endako deposit forms a west-northwest trending body that has a strike length of 3360 m and an apparent width of 370 m. It consists of four structurally distinct zones: Endako East, Endako West, Denak East and Denak West. Principal sulphide minerals of the deposit are pyrite and molybdenite, accompanied by magnetite and minor chalcopyrite. Galena, associated with wulfenite and bismuthinite, occurs in some ores of Endako West and Denak as minute inclusions in molybdenite. The sulphides and associated minerals are hosted by quartz veins which occur principally in vein systems. Hydrothermal alteration accompanying ore mineralization has pervasively kaolinized the quartz monzonite host rock, and has locally produced K-feldspar and quartz-sericite-pyrite envelopes on quartz veins.Primary structural controls of the deposit are southwesterly dipping vein systems which strike 110° in the Endako zones, 110° to 130° in Denak East and 170° in Denak West. Secondary structural controls are northeasterly striking vein systems that dip northwesterly in Endako East and southeasterly in Denak. Domal uplift accompanying the rise of latest stage magma is considered to have caused intense dilatant deformation along older west-northwest trending shear zones, producing an elongated structural host for ore deposition."

Jan 1, 1995

By Michael J. Rosko

Methods have been developed for processing and analyzing reflected solar radiation data obtained by Landsat 5 Thematic Mapper multispectral scanner. Spatial resolution for the Landsat series satellites is 30 meters per side per pixel. Materials on the Earth?s surface absorb or reflect different parts of the electromagnetic spectrum depending on their physical and chemical properties and, therefore, typically have characteristic spectral ?signatures?. Using these signatures, environmental parameters such as surface water and vegetation may be identified and analyzed. Principal advantages of the satellite image method for environmental monitoring include: a relatively long historic period beginning in 1985 for which information is available, the reliable numerical basis for the results, and the ability to assemble a historic environmental baseline and provide on-going monitoring for large or remote areas where standard monitoring methods may not be practical. However, because the long-term continued operation of Landsat 5 is problematic due to the age of the equipment, QuickBird and IKONOS satellite images were processed to determine if the two systems are sufficiently similar in their results to allow continuing monitoring using QuickBird data. The QuickBird satellite was launched in 2001 and collects the same visible and near infrared spectral bandwidths as Landsat 5, allowing for equivalent process algorithms for QuickBird, IKONOS, and Landsat 5 data. Spatial resolution for the QuickBird images is 2.4 meter per side, allowing for more detailed characterization of the land surface; spatial resolution for the IKONOS images is 4 meter per side. Because of several differences between the satellite systems, including degradation of the Landsat 5 sensor, it is necessary to calibrate QuickBird and IKONOS results to the Landsat results to verify similarity. Recent images from the satellite systems have been processed and results have been compared to determine the validity of comparing Landsat 5 and QuickBird/IKONOS images so that these newer data can be used reliably in the future instead of Landsat 5 data. Results from this comparison are presented in this paper and suggest that analyses for vegetation using the two satellite systems are comparable, and that little calibration is required. Results from comparison of surface water results from the two systems are less comparable and is currently being investigated by the authors.

Oct 1, 2009

By F. E. P. PEARSON

Sandstone quarried from an island in Lake Winnipeg is barged 130 km to a processing plant at Selkirk on the Red River. The stone is white, poorly consolidated, and consists of rounded quartz grains of high natural purity. It is an important supplier of silica in Western Canada for glass, fiberglass, foundry and other industrial uses.

Jan 1, 1984

By Claude Hubert, Alex C. Brown, Michel Richard, Rejean Sirois

"The Pierre Beauchemin gold deposit, situated 15 km NW of Rouyn-Noranda, produces an average of 1050 tonnes of ore a day. Reserves are 1.2 Mt grading 5.6 g/t Au. The deposit, located in a shear zone within the Flavrianpluton, in the Blake River Group, is hosted by four major rock types: meta-trondhjemite, meta-tonalite, hybrid rocks and meta-diorite (the prefu; ""meta-"" is omitted thereafter). The trondhjemite, tonalite, and metamorphic hybrid rocks are spatially distributed as a series of sub-horizontal tabular sills that form a genetically related group. Early fractures that permitted either the emplacement of pre-diorite felsic dikes or the formation of a visible alteration caused by early fluid circulation might have been developed in response to initial strain created during regional deformation. These fractures were precursors to the emplacement of diorite and the development of major shear planes. Sub-horizontal north-trending en échelon diorite lenses are observed at the mine. Together, these diorite lenses constitute larger scale diorite zones which are observed at the scale of the pluton. The diorite zones are interpreted as evidence of an episode of sub-vertical extension sustained by the layered trondhjemite, tonalite and hybrid system. The anisotropy created by the less competent sub-horizontal en échelon diorite was an important factor. In shear zone development and subsequent mineralization. The tonalite and diorite accommodated further defomation and developed the main N030°/40° ESE shears along with the spatially associated N060°/50°-60° SSE, and the N000°/10°-40° E shear zones. The N000° shears are interpreted as refracted or deflected equivalents of the N030° shears. The combined shears compose the Eldrich shear system which trends approximately N030°/40° ESE and has had a general reverse movement with a minor sinistral component.Gold mineralization occurs in all four major rock types as en échelon sigmoidal shaped lenses associated with the major N030° deformation system. The distribution of ore lenses can be divided into two categories: The first category occupies sub-horizontal diorite zones. The lenses trend N-S, dip 100 40° E, and are associated with shear zones, sub-horizontal fractures or tonalite-diorite contact planes. The second category of lenses is found in felsic granitic rocks; the lenses trend either N0300!40°ESE or N060°/50°-60° SSE. Local hydraulic breccia zones are observed near ore zones occupying felsic granitic rocks. These breccias may have resulted from high fluid pressures brought upon by confinement as a result of impermeable zones in an anisotropic tonalite-diorite system."

Jan 1, 1990

By A. Garnier, K. Tremblay-Bouliane, B. Gaillet, S. Moineau, D. Tremblay

"A heptapeptide library displayed on M13 bacteriophages (phages) was screened to identify peptide sequences able to selectively bind to gold, chalcopyrite, sphalerite, pyrite, and silica ores, and to evaluate phage potential as bioflotation reagents. Many peptide sequences were isolated through biopanning and differed from known sequences. Adsorption isotherms were determined and a receptor/ligand interaction model was identified and used to compare affinity of peptide sequences toward ores. Some phage sequences have slightly lower affinity to sphalerite than other sulphides. Adsorption was higher on sulphides than on silica. Induction time measurements suggested filamentous M13 phages lower hydrophobicity of the ore surface.RÉSUMÉ Une librairie d’heptapeptides présentés sur des bactériophages M13 (phages) a été criblée afin d’identifier les séquences peptidiques affinitaires à des minerais d’or, de chalcopyrite, de sphalérite, de pyrite et de silice et d’évaluer le potentiel de ces phages en tant que de bio-réactifs de flottation. De nombreuses séquences peptidiques ont été isolées par bio-criblage et différenciées d’autres séquences connues. Des isothermes d’adsorption ont été déterminées et un modèle d’interaction récepteur–ligand a été identifié et utilisé pour comparer l’affinité des séquences peptidiques par rapport aux minerais. Certaines séquences de phages possèdent une affinité légèrement inférieure pour la sphalérite comparativement aux autres sulfures. L’adsorption sur les sulfures était plus élevée que sur la silice. Des mesures de temps d’induction suggèrent que les phages filamenteux M13 diminuent l’hydrophobicité de la surface des minerais."

Jan 1, 2016

By J. K. Gowans

The Research and Design group of the Project Development Division (PDD) of Placer Dome Inc. includes metallurgical, electrical, civil and mechanical engineers. They provide metallurgical research and conceptual flowsheet development, feasibility concepts for the processing and ancillary facilities, and manage the detailed design of the facilities once approval has been given to a mining project. This paper describes how this group works, within the Project Development Division, to help develop feasibility studies with the Evaluations Group, manage detailed design, and provide support for the Construction Group. The paper briefly reviews the history and growth of the group and describes how it is evolving. The role of outside engineering firms and how they are incorporated into the division’s objectives are also discussed. The paper highlights the differences between Placer Dome’s Project Development Division and other mining groups, and why this approach fits the way Placer Dome does business.

Jan 1, 1998

By E. Chiyangwa, L. Schoeman

The commercially successful electrowinning and refining of metals typically requires the optimization of the electrolyte composition and operating parameters to produce high quality compact electroplated metal. The prediction of the effect of the electrolyte composition on the structure and morphology of the plated metal remains a challenge. Initial work on the use of polarization measurements to predict and control plating behaviour in electrowinning plants involved potentiodynamic polarization but proved unsatisfactory as accurate and repeatable predictions could not be achieved. The aim of the present work was to develop a reliable galvanodynamic technique specifically applicable to the plating of zinc from sulfate electrolytes with which plant operation may be controlled and optimized. Initial results indicated that plating and nucleation potentials could be measured accurately and repeatably and that the relationship between the two could be used as a predictive tool for the effect of electrolyte composition on the quality of zinc electrodeposits.

Jan 1, 2014

By Robert B. Parsons

"While it might seem like heresy to suggest that ""taxation"" can be a source of financing, never the less some generous tax rules can considerably enhance the tax savings pertaining to a particular expenditure or project. A basic tax knowledge, and careful tax planning, can optimize government participation in a project. INTRODUCTIONIn trying to identify sources of financing for a project, ""government"" as a source of funding is normally thought of in terms of government grants, loan guarantees, interest rate buy downs, property tax waivers, hydro subsidies, and so on. Generally, such concessions are somewhat difficult to obtain, especially in the current period of apparent fiscal restraint. One source of government funding which should not be overlooked is the income tax regime, and, at the provincial level, the various provincial mining tax regimes.While the taxpayer would not normally view a tax system as a potential source of government financing, nevertheless various federal and provincial rules applicable to the mining industry can offer attractive tax deductions - and tax savings - with respect to particular expenditures. In fact, it is not unusual for a civil servant to refer to a tax deduction as a tax ""subsidy"". For example, in the right circumstances, the cost of a smelter expansion in New Brunswick would cost the operator only 31 cents on the dollar, with the federal and provincial governments paying for the other 69 cents by foregoing tax revenues (Table I). In a sense, such tax savings could be compared to a government grant equal to 69% of project costs. Of course, not every project expenditure will generate that degree of government funding. The fact of the matter is that the percentages of tax savings attached to different expenditures cover a wide range, depending on a complex mix of factors. The point to understand is that the tax rules can offer some valuable savings, even after tax reform, and that a basic knowledge of the tax rules can yield some fruitful rewards."

Jan 1, 1989

By W. E. Selnes

Introduction In 1938, a survey conducted by the Ontario Mining Association revealed a rather startling fact. Injuries incurred in chute pulling were more numerous than those from any other single cause. This report prompted Mr. W. B. Paton, then Inspector of Mines for Manitoba, to make a similar survey of the mines of his Province. It indicated that, in Manitoba mines, chute accidents ranked second only to those from falls off roofs and sides. Why has the mining industry been so slow to recognize the dangers of chute pulling? A partial answer may be the lack of any systematic classification of accidents according to their real cause. The result has been to attribute to other causes injuries which were a direct outcome of chute pulling, and, indeed, has made it difficult to analyze accidents in the industry as a whole. Perhaps, too, because chutes are generally located in the comparative safety? of the drifts, there has been a tendency to consider the occupation as not very hazardous. Not until enough statistics were obtained on this particular task could it be appraised correctly. The Mining Association's survey has been most helpful, and latterly the industry has done a great deal toward analyzing the causes of chute accidents and toward determining an effective means of overcoming them. Much, however, remains to be done. An effort will be made in this paper to outline methods which have been found successful in materially reducing the number of injuries. Qualifications of the Chute Puller First of all it must be realized that chute-pulling is a specialized occupation. The men require proper training for the job, just as in other mining operations. Care must, therefore, be taken to choose persons whose qualifications fit them for the job. Chute-pulling is an integral part of the general mining operation and cannot be considered as isolated from the tasks of other workers. One of the essential qualifications of a chute-puller is a sufficient knowledge of mining operations to appreciate the effect his work will have on the safety of others in the vicinity. He must take the necessary precautions, by verbal warnings, by placing barricades and signs, or by personally guarding the chutes, to prevent accidents to fellow workers.

Jan 1, 1947

By L. Li

To accommodate the large payloads and harsh operating conditions associated with heavy vehicles in the mining industry, off-the-road (OTR) tires are typically used with heavy mining vehicles. These tires have increased abrasion and wear resistance due to their thicker tread, sidewall and bead thicknesses. Given these features, OTR tires are much stiffer than conventional passenger vehicle tires and cannot be mounted to a single-piece rim without damaging the structural integrity of the tire during the mounting process. Therefore, multi-piece wheels are used with OTR tires to facilitate mounting. While these assemblies are necessary, several instances of their failure have been reported to result in injuries or fatalities within the mining workplace. Many of these failures were specifically reported to be caused by the disengagement of the wheel lock ring - a component used to securely engage the assembly during operation. In this study, a threaded-connection locking mechanism has been proposed in place of the traditional lock ring design. The performance of this threaded-connection was numerically evaluated in a pull-out test against a conventional five-piece wheel assembly. The pull-out test was devised as a means of quantifying the engagement ability of each wheel?s locking mechanism. A high degree of modelling accuracy was maintained throughout the analysis by validating the vertical and horizontal static loaddeflection behaviour of the rim model of the five-piece wheel assembly against experimental data. Through validation, the model data were found to be within 10.5 and 4.80 %, for vertical and lateral loaddeflection behaviour, respectively. Results from the pull-out analysis found that the threaded-connection demonstrated a 113 % increase in the force required for disengagement to occur relative to the conventional five-piece design - a force of 9,550 kN in total.

Aug 1, 2013

By Rachel S. Prudhomme, Michael L. Jeremic

"The consolidation of mine backfill by free zing is a concept which has been under study in the mining engineering laboratories at Laurentian University during the past three years. The proposed underground application of freezing involves the artificial freezing of in-situ backfill by means of a refrigerated brine solution which would be circulated through a circuit off freeze pipes. The most interesting findings to date are: (I) The uniaxial compressive strength off frozen fill is considerably higher than that of cemented fill in a ratio of 20:1 (aggregate to cement), and (2) load deformation characteristics of the frozen fill suggest that a higher ice content results in more brittle failure and that samples which have initially failed can still support up 10 one-half the ultimate load without additional failure.Although at this early stage a derailed economic analysis of the procedure has not been possible, a general evaluation of the costs involved suggests that the method could be competitive with the hydraulic placement of cemented backfill. Results obtained from laboratory investigations indicate that the freezing of backfill is a structurally feasible option .IntroductionGround consolidation by freezing is based on the principle of transformation o f water contained in an aggregate-slurry into ice, which act s as a binding agent between the bulk particles, and which results in the transformation of a granular soil into a ""rock -type"" material. The abrasive nature of the particles enhance s the strength o f the ice by providing internal friction. As a result of this internal friction, the chances of plastic flow of the frozen mass when in a loaded condition are reduced(1). T he strength of a frozen aggregate is al so dependent on the grain shape of the aggregate particles which may or may not promote particle interlocking(2) and on the temperature since, below the freezing point of the water/aggregate mixture, the strength of the frozen mass increase s with decreasing temperatures.In the shaft sinking industry, artificial freezing of loose , unconsolidated soils has been in practice for several decades. Shafts for Saskatchewan 's potash industry have been sun k to depths of 3000 feet by employing artificial freezing to stabilize the Blairmore Formation(3). The common procedure for freezing ground for shaft sinking is summarized as follows(4,5): I) 150 mm diameter bore holes spaced on 1.5 m centres are drilled in a circular pattern with a radius of 1.5 m outside the periphery of the proposed shaft."

Jan 1, 1985

By Rashid Bashir

The presence of groundwater in the form of large aquifers can have an important influence on investment decisions for underground mines. The design for such mines requires development of special mining methods, and mine dewatering infrastructure to avoid hazards during shaft sinking and underground development. The costs associated with mine drainage control and Mine Dewatering Systems (MDS) are relatively small compared to the huge consequential losses that can occur in case of an uncontrolled inflow and subsequent flooding of the mine. The design of MDS needs consideration of accurate prediction of the maximum uncontrolled inflow rate, availability of the system during an uncontrolled inflow while the inflow is mitigated, and decision on pumping system technology to have capability to operate under water. The research presented in this paper provides a theoretical framework for a reliability based design procedure which takes into account the uncertainty in the estimate of the maximum uncontrolled inflow, performance of the system during the period of an uncontrolled inflow and a methodology to decide on appropriate pumping technology considering the reliability of the system and available underground storage. The reliability based mine design procedure integrates the ideas of Effective Reserve and Hydraulic Reliability Index to come up with a unified methodology for design of Mine Dewatering Systems.

Aug 1, 2010

By H. Al-Kazzaz

The 2-mm butt joints of ZE41A-T5 sand castings were laser welded using 1.6 mm EZ33A-T5 filler wire and a continuous wave Nd:YAG system at a power of 4 kW, surface defocusing and various welding speeds, Compared with the base metal, the fusion zone showed significant grain refinement due to high cooling rate, No grain coarsening was observed in the heat affected zone (HAZ). The porosity area percentage and total solidification crack length in the fusion zone (FZ) were reduced as the welding speed increased from 4 to 7 m/min, Fusion zone area, total penetration depth, and weld width decreased with increased welding speed, The hardness in the FZ was similar to or higher than the base metal after a natural aging of about one year, but there was a drop in the hardness of the HAZ, The HAZ width decreased with increasing the welding speed, Tensile test showed that a joint efficiency of approximately 75 ? 90 % was obtained.

Jan 1, 2005

By M. S. Moats

"The effects of commercial copper electrorefining additives (glue and thiourea) on the electrochemical removal of bismuth are of importance in copper production. It was found that Bi(III) electrodeposition occurs readily from acidic sulfate solution via a diffusion-controlled quasi-reversible reduction. The diffusion coefficient of Bi(III) was measured and found to be less than reported values of copper in similar solutions. The presence of thiourea and/or glue was found to accelerate or de-polarize Bi(III) reduction on stainless steel as compared to the inhibition or polarization of Cu(II) reduction. The additives also inhibited the dissolution of the Bi-Cu co-deposit during cyclic voltammetry. During short term deposition studies, the additives increased the concentration of Bi in co-deposited Cu-Bi products from solutions with low concentrations of Cu (<2 g/L). Bi deposition was significantly suppressed by increasing the Cu(II) concentration in the solution. The formation of a copper layer on the stainless steel electrode appeared to significantly suppress the reduction of Bi(III). This study demonstrates that glue and thiourea depolarize the deposition of bismuth on stainless steel. Therefore, the additives could be used to improve Bi impurity removal during third stage liberation.INTRODUCTIONThe production of high purity copper has been steadily increasing due to the wide application of the metal and its alloys in electrical and electronic products, infrastructure construction, industrial machinery and equipment, general products and transportation (Moskalyk et al., 2003). Most high purity copper is manufactured from copper sulfide mineral concentrates and/or scrap via a pyrometallurgical process followed by electrorefining (Navarro et al., 1999). During the electrorefining process, cast anodes of 99-99.5% purity are electrochemically dissolved into an acidified copper sulfate solution while high purity copper (>99.99%) is plated on stainless steel blanks or copper starter sheets (Davenport et al., 2002). The control of cathode deposit growth (purity and morphology) while maintaining a high current efficiency is of significant importance for copper refining (Ilkhchi et al., 2007). At typically applied current densities for industrial copper electrorefining, mass and charge transfer play important roles in the quality of cathodic products (Hiskey et al., 1998). If the real current density at some surface points is substantially higher owing to uneven current distribution, then rough spots can and will grow faster leading to nodules (Suarez et al., 1992). Nodulated deposits tend to capture solution and anode impurities (slimes) resulting in unacceptable cathode quality (Afifi et al., 1987). Furthermore, these nodules can grow until they eventually contact the anode leading to short circuits and current efficiency reduction (Ilkhchi et al. 2007)."

Jan 1, 2016