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By R. M. Kalanchey

The application of pressure oxidation processes to copper feed materials has gained increased exposure in recent years and some of these processes have made commercial inroads, although rather limited to date. Among the hydrometallurgical processes with significant commercial potential, Dynatec's copper pressure leaching process has been applied to arsenic-bearing copper materials and has shown, through a number of batch and continuous test programs, that pressure oxidation is a technically feasible option for the recovery of copper with coincident sequestration of arsenic in an environmentally benign residue.

Jan 1, 2007

By D. Kim

Kennecott operates one of the largest and most modern copper refineries in the world at Magna, Utah, USA. The inputs to the refinery are anodes produced at Kennecott Smelter, which has extremely high contents of lead and bismuth. In order to minimize undesired effects in the electrolytic refining process, unwanted impurities, especially bismuth, must be controlled. This paper describes the process development of practicing state-of-the-art quality control and presents the pilot test results of using the MRT Technology for Bi production.

Jan 1, 2007

By Y. Kocaefe, D. Kocaefe, G. Ergin

Filtration efficiency depends strongly on the wetting of the bed media by aluminum. This project was undertaken to study the wettability of different types of bed media (tabular alumina) using sessile-drop and infiltration techniques. The samples were analyzed using optical microscopy, SEM, and TEM to study the chemical interactions. The results indicate the spinel formation at the interface. This paper presents some of the findings which compares the two methods and gives the results of the analyses on the wetting of alumina by aluminum.

Jan 1, 2004

By N. Maleki

In recent years, research and development of magnesium alloys have been greatly promoted by the lightweight requirements in critical industries. The use of these alloys, however, has been restricted by their limited mechanical properties especially at high temperatures. The disadvantages can be overcome by producing Mg matrix composites. The Mg?Si alloys containing in situ Mg2Si particles have found a great potential as structural materials. Unfortunately, Mg2Si compounds are prone to form undesirable coarse Chinese script morphologies, which would deteriorate the properties of the materials. Refinement of microstructure is performed for improvement of wear and corrosion resistance. This paper investigates the microstructure and corrosion behavior of pure magnesium, unmodified and modified magnesium matrix composites reinforced with Mg2Si particles. The Mg2Si/Mg composite was prepared via a normal cast route, and then various amount of zinc was added to melt in order to modify the Mg2Si reinforcement particle morphologies. The microstrucrures were characterized by optical and scanning electron microscopy followed by EDX analysis. The corrosion behavior of Mg/Mg2Si composite was investigated by using potentiodynamic polarization measurements. The results showed that by addition of zinc, the average size of the primary Mg2Si became significantly decreased from about 100µm to about 20µm, as well as its morphology changed from dendritic to a polyhedral shape. However, by adding extra amount of zinc many primary Mg2Si particles become coarse again. It was also found proper amount Zn addition increased the corrosion resistance of Mg/Mg2Si composite.

Oct 1, 2011

By J. R. Perumareddi, V. S. Sastri, M. Elboujdaini

Economics of corrosion, the corrosion modes and causes, corrosion control methods to combat corrosion, along with a summary of issues and their implementation in the aerospace industry are briefly discussed.

Jan 1, 2004

By Z. D. Hora

Numerous asbestos occurrences are known, and the Cassiar Mine in Northern British Columbia has been a major producer since 1952. The Kutcho Creek deposit is a large medium-grade deposit of potential economic interest. OF THE numerous British Columbia asbestos occurrences, only one mine exists. Another property, at Kutcho Creek, may be commercially viable. Cassiar Mine, in the northern part of the province, has been producing high-quality asbestos since 1952 and is described elsewhere in this volume. The Kutcho Creek property is situated north of Letain Lake about 125 km southeast of Cassiar Mine. The Kutcho Creek asbestos deposit comprises zoned chrysotile fibre veins in a well jointed and locally sheared serpentinite sill. The sill intrudes, more or less concordantly, a sequence of Devonian to Mississippian argillaceous Industrial Minerals in Canada metasedimentary, calcareous, and volcanic rocks. The light to dark green serpentinite contains crossfibre chrysotile veins that are usually less than 1 cm in width but up to several metres in length. Typical sections in exploration drillholes grade between 2.5 and 3.0 per cent fibre. According to the last assessment report submitted, test results indicate that the Kutcho Creek property may contain a large, medium-grade asbestos deposit of potential economic interest.

Jan 1, 1984

By F. Rojas, M. Sanchez, J. Palacios, O. Pavez

Copper sulfide is the main mining resources in Chile, and most of this metal is obtained via pyrometallurgical extraction in seven copper smelter plants, which extends from the northern Atacama desert to the central part of the country. In 2002, 1,522,000 metric tons of fine copper were produced, with a notorious environmental impact due to the large amount of slag generated, including transportation and disposing problems. Therefore, there is a great interest in finding alternative uses in order to give additional value to the slag. This is a total project development concept, which consider residues as new resources where new components could be obtained, improving sustainability in mining activities and also ensuring clean production processes. Thus, the present work shows a review of copper slag characterization as well as several ways of utilization, including compact material for road and railway installation, part of admixtures in concrete.

Jan 1, 2004

By Xiao Huang, Jean-Francois Thibault, Ali Merati, Prakash C. Patnaik

Single-crystal nickel-based superalloys are the current state-of-the-art technology for the manufacture of turbine blades. This technological improvement of the turbine blade has brought a considerable increase in its cost. Repair and overhaul of service stressed single crystal turbine components is an economic necessity for life cycle cost reduction of engines since the cost associated with replacement is significantly higher than its counterpart polycrystalline component. This paper will first review the recently reported research in developing repair technologies used for DS and SX components. These techniques repair the crack or defect while at the same time ensuring that the mechanical properties do not deteriorate and, more importantly, that the single-crystal microstructure is not jeopardized. It will then be followed by a brief overview of the research conducted and initiated by the authors with regards to the repair of single crystal alloys.

Jan 1, 2004

Experimental determination of the response of an AG/SAG mill treating two components of significantly different impact resistance is challenging for two main reasons: firstly, small scale laboratory tests have yet to be confirmed as valid representations of the full scale milling environment, and secondly pilot plant testing requires 10-20 tonnes of ore per scenario which precludes the use of drill core, rendering the process very expensive. In order to mitigate these difficulties, modelling was considered as a potential way forward. However, as the JKSimMet AG/SAG model currently has no capacity to simulate the interaction of two ore types with differing impact resistance, density and/or feed size distributions, an alternative modelling approach was developed. This approach aims to essentially calibrate the AG/SAG process under a set of given conditions, for which survey data and the ore properties of the main components in the feed blend already exist. This paper describes a new conceptual model, which provides a simplified approach for investigating the multi-component behaviour of two ores of differing hardness/SG in a given AG/SAG milling environment, and which can potentially be used for scale-up from laboratory/pilot testwork and geometallurgical estimation of throughput.

Jan 1, 2012

By C. B. Webber

"Sherritt Gordon's experience with rubber mill liners began in 1964 at the Lynn Lake Farley Mine and continued at the Fox Mine in 1960, and the Ruttan Mine in 1973. This paper describes the history of the performance of rubber mill liners at the three mine operations.LYNN LAKE - FARLEY MINEThe Lynn Lake Farley Mine, which ceased production in 1976 due to exhausted ore reserves, was a 3500 T.P.D. copper-nickel operation; consisting of two parallel rod mills followed by three stages of ball mill grinding. A circuit modification in 1964 necessitated one of the tertiary ball mills to be used as a pyrrhotite regrind mill. This 8' x 5' Hardinge conical mill drawing 225 HP was initially installed with steel liners and lifters. After several months of operation a routine inspection revealed severe channeling and washing behind the liners which was threatening to erode the ball mill shell. It was thought that the highly acidic condition in the mill, due to grinding 100 º6 pyrrhotite, was accelerating the wear of the steel liners. At this time it was decided to reline the mill with rubber liners to see if the wear problem could be relieved, and in December 1964 a set of Skega rubber liners were installed."

Jan 1, 1981

By Julie Q. Shang

The electrokinetic (EK) technology for dewatering of two tailings from the uranium mines in Northern Saskatchewan is studied in bench scale experiments. The study includes four phases: 1. Characterization of two uranium mine tailings; 2. Assessment of voltage loss on the coated Ti anode and water interface. 3. EK cell test series to measure electrokinetic permeability (ke) of two tailings; 4. EK dewatering test series to study electrokinetic enhanced gravity dewatering on two tailings samples. The results have demonstrated that both tailings responded positively to the EK process. For the tailings containing gypsum, the EK dewatering should be a short term process (within one hour) with anode conditioning (pH adjustment). The tailings containing clay minerals responded well to EK dewatering, in which pH adjustment is optional and will further enhance the EK flow. Both tailings as tested have low hydraulic conductivity and are particularly suitable for EK dewatering and consolidation.

Aug 1, 2010

By E. Ferguson

In evaluating refractory designs for cast house applications, thermal calculations are frequently performed to determine cold face shell temperatures, temperature profiles and metal freeze plane locations within the refractory layer, and heat loss in the steady state condition. A problem arises when looking at molten metal transport crucible designs in that these structures are usually operating under non-steady state conditions throughout their production cycle. Because the molten metal temperature varies with time, and material properties such as thermal conductivity are temperature dependant, mathematical solutions are at best... complicated. This paper presents a relatively simple, iterative solution, that can be set up on a standard computer spreadsheet program, to calculate heat transfer in non-steady state conditions. These calculations can provide curves for (1) molten metal temperature vs time and (2) cumulative heat loss vs time, given variable starting conditions, to aid in the evaluation of molten metal transfer crucible refractory designs.

Jan 1, 2004

By R. A. L. Drew, F. Edelmann

Brazing is a low-cost process used extensively in the manufacturing and repair of aircraft gas turbine engines. Components within the compressor stage of the engine experience relatively low temperatures (600-700°C), therefore joints of stainless steels are typically employed. In such joints, a Pd-Ni-Cr-Si-B (PalNiCroTM) brazing alloy is used as a sealant, however brazing procedures are not well understood. The wetting behavior of PalNiCroTM on AISI 347 was evaluated with respect to contact angle. A microstructural evaluation was carried out with variable joint clearances. Microhardness profiles were performed to investigate the presence of hard secondary phases, which were later confirmed by electron microscopy. The results indicated an equilibrium contact angle of 10° within 100 seconds. The average microhardness of the braze layer and base metal were approximately 550 and 205 VHN, respectively. At the interface, a diffusion zone was present containing carbides and borides.

Jan 1, 2004

By A. Yousefpour, M. Hojjati, M. Simard, M. Laramée, M-A. Octeau

The need for effective and reliable joining methods grows as the use of advanced thermoplastic composites becomes widespread in aerospace industry. An experimental investigation of resistance welding of APC-2/AS4 thermoplastic composite laminates is presented. In this method, a heating element is placed between the bond-surfaces then the interface is heated by passing electrical current through the heating element. The polymer at the weld interface is melted due to resistance heating, then diffuses and consolidates under applied pressure, resulting in a weld. APC-2/AS4 prepreg, APC-2/AS4 commingled, and different grades of metal mesh heating elements were considered. A custom made resistance welding rig was designed and developed to perform lap-shear welds. The mechanical performance of the welds was quantified using single lap shear tests. The effects of different heating elements on the mechanical performance of the resistance-welded parts were investigated. Also, quality of the welds was examined under optical microscopy.

Jan 1, 2004

By B. T. Lu, J. L. Luo, J. F. Lu

The present paper investigates the chemo-mechanical effect in slurry-erosion corrosion process of carbon steel to understand the synergistic mechanism due to interaction of chemical and mechanical factors. The erosion-corrosion tests were conducted with A1045 steel in slurries comprising tap water and silica sand. Various heat treatments were adopted to achieve different hardness in the test material. The chemo-mechanical effect is evaluated in line with the correlation between the degradation of hardness in the surface layer and anodic current density. During the erosion-corrosion tests, various anodic currents were applied to find the relation between the anodic dissolution rate and erosion rate. The experimental results indicate that the hardness decreased with increasing anodic dissolution. Based on the fact that pure mechanical erosion rate increased with decreasing hardness, this result suggests that the corrosion-induced degradation of mechanical property is a mechanism of corrosion-enhanced erosion. This theoretical prediction is verified by erosion-corrosion experimental results.

Jan 1, 2004

By S. Parada, P. T. Jones, M. Guo, S. Smets, E. Boydens

The corrosion behaviour of a pitch-bonded MgO-C refractory in contact with a vacuum oxygen decarburisation slag with high Al2O3 content (12-17 wt%) is investigated under VOD process conditions by rotating finger tests in a vacuum induction furnace. The refractory degradation mechanisms are studied by the characterisation of the corroded microstructures using scanning electron microscopy, equipped with energy dispersive spectroscopy. The influence on the refractory wear of the process temperature, corrosion time and the Al2O3 content in the slag is discussed. The degradation mechanisms include slag infiltration, direct MgO dissolution from the refractories into the penetrated slag, erosion of magnesia grains at elevated temperatures, removal of carbon through the MgO-C reaction, and finally, oxidation of refractory carbon by reducible slag components. Both a porous MgO layer and a dense (Mg)(A1,Cr)2O4 spinel at the slag/brick interface were observed. Their formation mechanisms and industrial relevance are discussed.

Jan 1, 2004

By Pierre Boulanger

This paper describes a generic technology for modeling in real time the various operations of surface mines. Based on various sensor fusion techniques and high-speed network, a virtual reality model of a mine capable of representing not only static infrastructures but also mobile equipment such as trucks and excavators is created. The modeling technique deal with a wide range of sensors such as survey data, satellite pictures, ore concentration, machine condition indicators, video, sound, real-time GPS locator, range sensor, etc. The model created allows for every piece of information to be displayed in context allowing for a better temporal and spatial correlation of events by mine operators, planners, and supervisors. Syncrude, a Canadian mining company located in northern Alberta, is planning to use this technology, not only to understand oil sands mining processes better, but also to give decision-makers better access to the timely, accurate information from the field that they need to make informed decisions.

May 1, 2001

By BARRY BANNATYNE

Ombrotrophic Sphagnum peat bogs have a characteristic signature on both colour injrared film (750 nm to 3,000 nm response) and Daedalus injrared line-scanner images (thermal infrared 3 to 5 microns and 8 to 14 microns response). This remote sensing method was used to survey bogs in southeast Manitoba to delineate targets for surface exploration. Target bogs all have a surface growth of Sphagnum; underlying dead Sphagnum ranges from 1 to 6 m thick. Large Sphagnum reserves exist in the Caribou cluster of bogs, and in /979 a bog first identified by infrared sensing was brought into production.

Jan 1, 1984

By M. Bertrand

Oxalic precipitation is usually applied to process radioactive wastes or to recover actinides from a multicomponent solution. Precipitation reactions being highly sensitive to many operation parameters, the computer simulation appears to be a very effective tool to forecast the evolutions of the system subjected to various operating conditions. This study focuses on the tetravalent uranium oxalate precipitation modelling which combines population balance and hydrodynamics. Both experimental and numerical studies are carried out in order to analyse the reactor design influence on the precipitate characteristics. The simulations taking into account primary nucleation and crystal growth are in agreement with experiments.

Aug 1, 2010

By M. Rigaud, K. Sankaranarayanane, X. Zhou

The effect of varying fine alumina/ultra-fine alumina ratio on the Bingham to dilatancy transition in alumina based, self-flowing refractory castables has been studied in detail employing rheological tests and particle size distribution measurements. Analysis of flow resistance and torque viscosity values has shown that Bingham to dilatancy transition is strongly influenced by fine alumina/ultra-fine alumina ratio in the castable, as well as by the nature of ultra-fine alumina. The calculated values of rheological constants and the viscosity coefficient were found to increase at higher fine alumina/ultra-fine alumina ratios.

Jan 1, 2004