Teck Cominco Ltd.

Mississauga, Canada

Teck Cominco Ltd.

Mississauga, Canada
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Zhang G.X.,Teck Cominco Ltd.
Journal of the Chinese Society of Corrosion and Protection | Year: 2010

Steel is the most important engineering material while galvanizing is the most effective method for corrosion protection of steel. This article reports the results of a study on the efficiency of corrosion protection by zinc coating in various natural environments based the corrosion rate data collected from various parts in the world. The potential and development direction for more corrosion resistant zinc based coatings are then discussed. More corrosion resistant zinc coatings could extend the application of galvanized steel beyond atmospheric environments much more into other environments such as soil, water, concrete or chemical environments. Comments are also made regarding the relevance of corrosion tests in relation to new coating development. This article was written in behalf of the International Zinc Association.

Mohammadi Zahrani E.,University of British Columbia | Cuevas-Arteaga C.,University of British Columbia | Verhelst D.,Teck Cominco Ltd. | Alfantazi A.,University of British Columbia
ECS Transactions | Year: 2010

The corrosion resistance and degradation mechanisms of 625 supperalloy at 800 °C under three molten salt compositions containing PbSO4, PbO, PbCl, ZnO, Fe2O3 and CdO in air atmosphere were studied. The concentrations of Fe2O3 and CdO were varied to evaluate the effect of these compounds on the corrosion reaction. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization technique were applied to evaluate the degradation mechanisms and corrosion properties of the alloy. Corrosion products and surface layer of the corroded specimens were studied by SEM/EDX and X-ray map analyses. Electrochemical evaluation confirmed that increasing the concentration of CdO in the molten phase could increase the corrosion rate of the alloy and in this condition the corrosion phenomena occurred under the control of charge transfer effect. The presence of a Cr-depleted layer on the surface of the alloy was the reason for the formation of an internally attacked area at the alloy/oxide interface. ©The Electrochemical Society.

Zhang K.,Teck Cominco Ltd. | Filc A.,Teck Cominco Ltd.
SAE Technical Papers | Year: 2011

A new high fluidity zinc die cast alloy was developed at Teck Metals' Product Technology Centre. This hot chamber die cast alloy is based on the commonly used ZAMAK alloys but possesses up to 40% better fluidity. Industrial trials and evaluations have confirmed the excellent fluidity of the alloy as well as the easy use and adoption of the alloy. Tests have shown the alloy has comparable physical, mechanical and corrosion properties as Alloy 3 and 7. The alloy is best suited to be used for casting parts with section thickness less than 0.45 mm. It can also be used for casting parts that are difficult to fill or have high surface finish requirement. Copyright © 2011 SAE International.

Cuevas-Arteaga C.,University of British Columbia | Verhelst D.,Teck Cominco Ltd. | Alfantazi A.,University of British Columbia
ECS Transactions | Year: 2010

The nickel-based alloy 625 in the form of thermal sprayed coatings, as weld overlay, and as an alloyed material has been used extensively to minimize high temperature oxidation and hot corrosion in incinerators, supercritical water oxidation processes, biomass-fired plants, and other industries. Corrosion in these applications occurs due to the combination of gaseous species in the form of CO2, O2, SO2, and HCl; and solid impurities which form chlorides and sulphates of alkali and heavy metals (K, Na, Zn, Pb, Sn, etc) with low melting points. Even though alloy 625 has some shortcomings under certain conditions at high temperatures, the alloy from its beginning has had significant success, and its production has increased considerably worldwide. This paper will review some aspects for which alloy 625 is the material of choice and explain its unique features in many applications. ©The Electrochemical Society.

Spikings R.A.,University of Geneva | Crowhurst P.V.,Teck Cominco Ltd. | Winkler W.,ETH Zurich | Villagomez D.,University of Geneva
Journal of South American Earth Sciences | Year: 2010

New 40Ar/39Ar, apatite fission track and (U-Th)/He data from the late Cretaceous indenting and buttressing margins of Ecuador have been combined with previous thermochronological studies to constrain the timing of syn- and post-accretionary tectonic events in the Ecuadorian Andes to within ±1 Ma. Our interpretations are more accurate than previous hypotheses because i) they are more sensitive to lower temperatures (<60 °C), ii) we directly compare data obtained from in-situ and detrital rocks, and iii) they are constrained by recently published palaeomagnetic, stratigraphic and geochronological data. The response of the buttressing Ecuadorian margin to the collision of the Caribbean Plateau and its overlying arc was diachronous. Exhumation occurred as an immediate response to collision at ∼75 Ma, south of S1°30', whereas the northern region started to exhume at ∼65 Ma, suggesting that accretion may have been oblique. Elevated cooling and exhumation rates within specific massifs dispersed along the entire length of the Ecuadorian cordilleras, during 43-30 and 25-18 Ma, are attributed to i) an increase in convergence rates between the Farallon and South American plates during 42-37 Ma, and an increase in spreading rates in the southern Atlantic ocean, and ii) a change in the vector of the subducting plate, which changed from ESE to E at 25 Ma in response to fragmentation of the Farallon Plate. Previous suggestions that Eocene reactivation of the buttressing margin were driven by collision of the Macuchi Arc are shown to be incorrect. 40Ar/39Ar, zircon fission track, and apatite fission track and (U-Th)/He analyses from the Eastern Cordillera north of S1°30' reveal well defined periods of rapid cooling and exhumation at 15 Ma, 9-7 Ma and 5.5-0 Ma. Apatite (U-Th)/He data reveals late Miocene-Recent cooling and exhumation (≤1.3 km) of the southern Eastern Cordillera by a lower quantity than that experienced to the north (≥3.5 km). These distinguishable differences in cooling and exhumation are attributed to the collision of the Carnegie Ridge with the northern SOAM Plate at 15 Ma, and the subsequent subduction of high topography along the ridge at ∼5 Ma, which reactivated the serpentinised Campanian suture via dextral transcurrent displacement. © 2010.

Conlan M.J.W.,University of British Columbia | Mayer K.U.,University of British Columbia | Blaskovich R.,Teck Cominco Ltd. | Beckie R.D.,University of British Columbia
Geochemistry: Exploration, Environment, Analysis | Year: 2012

Mineral controls on molybdate (MoO 4 2-) solubility were studied to better understand the fate of molybdenum (Mo) in neutral rock drainage. Batch and column experiments lasting from 46-110 days predict that molybdate (MoO 4 2-) mobility is limited by powellite (CaMoO 4) and wulfenite (PbMoO 4) precipitation under neutral pH conditions with aqueous Ca and Pb present. Batch experiments demonstrate that wulfenite forms almost instantaneously and effectively removes Pb from solution to concentrations below detection limits. Powellite formation is kinetically limited, but has the capacity to significantly reduce Mo concentrations in the presence of calcite. An initial inhibition of powellite formation is observed, likely due to a lack of available nucleation sites. After the nucleation phase, powellite formation from supersaturated conditions follows a second order rate expression with linear dependence on Ca 2+ and MoO 4 2-. A column experiment provides further evidence of rapid wulfenite formation and kinetically limited powellite formation. Both powellite and wulfenite have also been identified in molybdenum-bearing carbonaterich waste rock sampled from barrel-sized field cell weathering experiments, providing direct evidence that these minerals affect Mo mobility under field conditions. In contrast to Pb and Ca, both Cu and Zn did not form distinct molybdate precipitates. © 2012 AAG/Geological Society of London.

Gao N.,Teck Cominco Ltd. | Liu Y.H.,Teck Cominco Ltd. | Tang N.-Y.,Teck Cominco Ltd.
Journal of Phase Equilibria and Diffusion | Year: 2010

The liquid domain of the Zn-Fe-Al-Mn quaternary system at 460 °C was experimentally investigated. The nature of relevant intermetallic compounds was studied using scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDS). A total of 12 Fe-oversatu-rated baths with various Mn additions was prepared for the study. When the Al addition was fixed at 0.14 wt.%, δ-FeZn 10 and δ-MnZn 9 were found to co-exist with the liquid phase at low Mn additions. Increasing Mn additions above 1.3 wt.% greatly stabilized δ-MnZn 9 so that it became the sole compound existing in the liquid phase. When the Al addition was fixed at either 0.16 or 0.27 wt.%, η-Fe 2Al 5 was found at low Mn additions but ceased to exist as Mn additions increased above 0.8 wt.%. The current study indicates that the addition of Mn to the bath promotes the formation of δ phases, thus shifting the invariant point of δ/η in the Zn-Fe-Al ternary system to a higher Al level. Based on experimental results, the liquidus surfaces in the Zn-rich corner of the quaternary system at 460 °C were schematically constructed, and implications for practical galvanizing operations were suggested. © ASM International.

Dong S.,Xiamen University | Zhao B.,Xiamen University | Lin C.,Xiamen University | Lin C.,Luoyang Ship Material Research Institute | And 3 more authors.
Construction and Building Materials | Year: 2012

The corrosion behavior of epoxy/zinc duplex coated rebar embedded in concrete is evaluated comparing with the black steel, galvanized and epoxy coated rebars for a long term in ocean environment. The effect of mechanical damages of epoxy coatings on the corrosion protection is examined. The epoxy coated and epoxy/zinc duplex coated rebars show the higher anti-corrosion performance than other types of rebars. However, once the epoxy coating is mechanically damaged, the more serious corrosion may occur in the damaged area of epoxy coated rebar in concrete. The epoxy/zinc duplex coating remains a good corrosion protection to steel in concrete even when suffering from some mechanical damages. © 2011 Elsevier Ltd. All rights reserved.

Welsby S.D.D.,Teck Cominco Ltd.
Materials Science and Technology Conference and Exhibition 2013, MS and T 2013 | Year: 2013

To consider seawater as a viable option during the early stages of a mineral processing project, a reliable laboratory flotation test procedure is required. This paper documents the development of such a procedure. Flotation with seawater was compared directly to flotation with fresh water. Flotation with seawater had higher variability in selectivity, caused by variable pyrite recovery. Mitigation techniques were unable to alleviate test variability; switching to an inert grinding environment completely eliminated test variability. There was a direct relationship between the recovery of pyrite and the redox potential of the mill discharge when grinding in a mild steel mill with seawater. These results showed that the source of variability with seawater was galvanic interactions between the mild steel mill and the ore, particularly those leading to oxidation of pyrite. Future test work will focus on controlling the extent of these galvanic interactions to improve the reliability of the procedure. Copyright © 2013 MS&T'13®.

Electrochemical cells having a cathode, a zinc anode including a mixture of zinc fibers and zinc powder, and electrolyte are provided. The zinc fiber and zinc powder may have selected physical and compositional attributes. Methods of preparing such electrochemical cells are also provided. Such electrochemical cells may provide improved discharging performance under power-demanding conditions.

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