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By S. Afshar, E. Dajoux, C. Allaire

For various reasons, molten salts, mainly chlorides and fluorides, are used in the aluminum industry. In the holding and melting furnaces, these salts may have different roles such as protecting the metal from oxidation, reducing the metal content of the skim or removing inclusions or impurities from the metal bath. However, the use of these salts may also have some undesirable effects such as easy attack of the furnace lining refractory materials by molten aluminum. The aim of the present investigation was to clarify and to compare the effects of chloride versus fluoride salts, on the corrosion process of the aluminosilicate based refractory materials. A laboratory test and procedure, simulating the conditions at the metal line in the aluminum treatment furnaces, was used. Different aluminum alloys (A1-5wt.%Mg, A1-5.5wt.%Zn and 7075 alloy) and chloride or fluoride salts (MgC12, KC1, CaCl2, NaC1, MgF2, CaF2, NaF and cryolite) were used as well as several aluminosilicate materials. Thermogravimetric measurements were also carried out in order to analyze the effect of the salts on the oxidation of molten aluminum alloys. The experimental results showed that fluoride salts are more aggressive than chlorides against the tested refractory products. It is postulated that the fluorides prevent the formation of a protective oxide layer on the metal surface, favoring at the same time the corrosion of refractories. Moreover, it was found that the presence of Na in fluoride salts increases significantly the aggressiveness of the aluminum alloy towards the refractory samples.

Jan 1, 2004

By M. Bueno

Between 1993 and 2003, a series of AG and SAG mill pilot plant trials were conducted using Hardinge Ical pilot plant scale SAG mills on numerous ore samples and ranging across a wide variety of operating conditions. The data from these tests were used to evaluate the design of SAG and AG mill circuits for over a dozen projects, of which about half were eventually constructed and commissioned. The data were also used in the development of SAG mill modelling, scale-up and simulation procedures by several consultants who had access to part of the data set. Recently, we have had the opportunity to bring this data together and further analyse the consolidated dataset. This paper reports on the outcomes of this analysis that has identified the impacts of different AG/SAG circuit flowsheets and operating conditions on energy efficiency and operating cost.

Jan 1, 2012

By H. Dundar, C. Dzomeku

An extensive testwork was performed around the HPGR plant at GoldFields Ghana Limited Tarkwa Gold Mine. The HPGR was used to prepare the feed for heap leaching. The circuit was configured in such a way that the edge material from the HPGR discharge was recycled for further crushing while the product from the centre reported to the heap leach section. The set-up of the Polysius HPGR provided an opportunity to study the effect of different design and operating variables. This paper will discuss the results from the tests performed to assess the effect of rolls’ speed and applied pressure on the capacity and the grinding efficiency of the HPGR. Applying different pressure values appeared to have an influence on the amount of edge material recycled.

Jan 1, 2012

What Discounted Cash Flow Analysis can do for you: ?Provide an accurate financial analysis of a project for the first 25 to 30 years of operations ?Identify cash flow requirements ?Identify relative sensitivity of the project to the various input parameters ?Place a value on the resource in place after 30 years of operations ?Correct for errors in input parameters

May 1, 2010

By Carol E. Jones

?Reclaiming the land? in the Athabasca Oil Sands is becoming a household phrase in Canada. Advances in soil salvage and placement, increasing biodiversity of forest ecosystems and improved design of the landforms are beginning to change the trajectory of the ?reclaimed land? towards a boreal forest. The boreal forest is much more than just a forest; in the area of Fort McMurray AB, roughly one half of the boreal forest is composed of organic wetlands, often called muskeg. How important is muskeg to the boreal forest ecosystem and to the local aboriginal people? Should muskeg be reclaimed? Can muskeg be reclaimed? Ten years ago it was broadly accepted that organic wetlands could not be re-established; in fact this was so well accepted that reclamation of organic wetlands had not been attempted. Over the past decade this conclusion has been re-evaluated and research projects have been undertaken to examine the potential to create organic wetlands in a reclaimed oil sands landscape. This paper examines these questions and the research initiatives necessary to reclaim the other half of the Athabasca Oil Sands.

May 1, 2011

Planning and operational problems Difficulty in getting accurate geological interpretation Hard to plan work in advance Constant changes in engineering drawings and specifications Occasionally, a small stope portion requires changing the mining method from room-and pillar to shrinkage The ground has to remain stable until the entire stope is mined out A large stope portion is mined as development (30%) Frequent corrective excavation work due to dip changes Unstable and inclined working surface Frequent rehabilitation work is required

Feb 1, 2008

By M. Sheedy

This paper discusses the short bed ion exchange technique for the removal of metal contaminants from copper electrolyte bleed streams. Processes for the selective removal of sulfuric acid, arsenic, antimony, bismuth, and iron will be discussed. A case study outlining the performance history of a short bed system for sulfuric acid removal followed by a two stage selective precipitation system producing a nickel carbonate by¬product at the Phelps Dodge Mining Company El Paso operation will be presented.

Jan 1, 2007

By J. H. Bernard, K. Zak

Abstract- The three traditional types of Variscan vein Pb-Zn-(Ag) mineralization recognized in the Bohemian massif from historic paragenetic studies are confirmed by modern metallogenic studies. Stable C, S, and 0 isotope data, as well as Pb and Sr isotopic ratios of the deposits, indicate a predominantly crustal origin of the constituents in all three types. Although the data also suggest differences in temperature and pressure of formation, and the oxidation conditions and nature of the hydrothermal fluids, nonetheless they are consistent with prevailing metallogenic classifications of the vein mineralization.

Jan 1, 1992

By H. Polkowska-Motrenko

Analytical methods for the determination of uranium and other precious elements in ores, industrial wastes and by-products have been developed. The analytical techniques employed are NAA and ICP-MS. Two procedures of digestion were applied: microwave acid digestion and alkali fusion. Accuracy was checked by using CRMs. Results of analysis of the same samples by the elaborated methods have been presented and compared. The methods will be used for estimating the capacity of uranium production for the Polish nuclear power programme.

Aug 1, 2010

The primary arsenic minerals in the uranium ore processed at the McClean Lake Operation are rammelsbergite, niccolite and gersdorffite. During processing, a large fraction (80 - 95%) of these reduced minerals is oxidized and dissolves primarily as As5+ in the leachate solution. In the tailings preparation circuit the dissolved As5+ is precipitated as a poorly crystalline form of the mineral scorodite. Following subaqueous deposition in the tailings management facility, a temporal rise and fall in arsenic pore water concentrations has been observed. This is due to the oxidation of the residual quantities of reduced arsenic minerals initially present in the tailings sediment. The XANES (x-ray absorption near edge spectrometry) technique has shown that the As1- is gradually oxidized to As3+ and then finally As5+ in the tailings sediment. This oxidation process results in a temporary accumulation of As3+ in solution and is the source of the rise and fall in arsenic concentration observed.

Aug 1, 2010

"No questions.F Energy Consumption in Industrial Minerals : E.Joe No questions.g Automatic Dewaterinq at Mattagami : M. CaronE. Marcotte Is the control valve on the thickener underflow reducedFalconbridge as the pulp density reduces?Reply As the slurry density reduces the valve will constrict to reduce the flow and the density will re-establish itself.E. Marcotte Is there a stopper on the valve to prevent its closing too far?Reply We never shut it off completely because of the danger of sanding. It is just brought down to a normal level. It works very well within a given range and the operator is on hand to prevent any sanding out in the line."

Jan 1, 1984

By Michael Nicol

A quantitative description of hydrometallurgical operations depends primarily on an understanding of the kinetics of the chemical and physical processes that take place in such operations. This paper will review the current status of kinetics in hydrometallurgy in terms primarily of the author’s experience in diverse unit operations. A distinction will be made between the popular use of models based on limited kinetic data and mechanisms which reflect the actual elementary chemical or physical steps involved in an overall process. Several examples will be used to illustrate this distinction. The proliferation of published papers of declining quality has resulted in the bequest to later researchers of outdated and often incorrect conclusions by a process that is often difficult to reverse. Some examples of these mysterious concepts will be examined and hopefully reversed. Finally, several examples will be given that identify significant gaps in our understanding of the kinetics of important processes that remain unresolved.

Jan 1, 2014

By M. Matsuda

The Hitachi refinery of Nikko Smelting & Refining Co. Ltd. began its electrolytic copper refining operations in 1911. In December 2002, the refinery changed its operation scheme by introducing the ISA permanent cathode technology for the first time in Japan. The change resulted in higher productivity, better cathode quality, and lower operational costs. The operation has been continuously improved to reach a 20% higher production capacity than the original one. For the electrolyte purification process, the Hitachi refinery has developed a new process for removing impurities. The process involves As, Sb and Bi adsorption from the electrolyte by means of chelating and ion exchange resin. The new resin process will achieve higher efficiency in removing impurity.

Jan 1, 2007

By Steven Dempsey

Overview What is Tubbing? A look at Cigar Lake Tubbing Design The Tubbing Installation Backwall Grouting

May 1, 2013

By Jean Fortin

In order to remain competitive, the search for excellence has been and will remain the only viable option facing the Mount-Wright operations. Safety and environment, process and technology as well as cost performance have been the focus points on which the operations have concentrated their efforts in order to meet and exceed our company's "Vision 2000" plan. Some of our mine's accomplishments have been a new work organization, a world class maintenance and a new collective agreement. The concentrator, maintenance and production departments have evaluated their processes and implemented various improvements in areas such as power supply, dewatering, blasting, implementation of service centers for large and small vehicles, fleet standardization, crusher, mills and silos improvements... etc. Safety and work environment for personnel have been our driving force in order to achieve this plan.

May 1, 2003

By W. Wallace

The aerospace industry celebrated 100 years of powered flight in 2003, and the remarkable achievements that have occurred during the past 100 years are in no small way due to major developments in materials. Modern alloys for airframes, engines and other major sub-systems have evolved through the intelligent application of new processing concepts involving melting, casting, hot and cold working, heat treatment and more recently vapour phase processing. Alloy design has evolved in parallel to allow maximum benefits to be achieved from these processing advances. However, the pace of development seems to be slowing and future gains are likely to be made by learning how to extract major value from aerospace assets. Understanding the modes of deterioration and establishing cost effective lifetimes by holistic life cycle management seem to be the way of the future. Extending component lifetimes by repair, rejuvenation and refurbishment are all viable possibilities and they offer great opportunities for Canada, which, traditionally, has been a major user of modern aerospace materials rather than a supplier. The challenges for metallurgist, physicists and engineers will be no less than in the past and should create new business opportunities for Canada. The scenario described above will be developed by calling upon examples drawn from the author's experience.

Jan 1, 2004

By Y. Turen, Y. Karakas, E. Candan, C. Sahinturk

In this study, wettability between sprayable tundish lining (MgO) and molten steel was investigated by using sessile drop method. Content of glass fiber (SiO2) in the MgO varied between 0 to 8 wt% whereas mean particle sizes of the MgO were 25, 75, 150 and 300µm. Experimental results revealed that contact angle (0) of sessile drop on the MgO was not altered by the addition of glass fiber up to 1 wt.% whereas above 2 wt.% addition decreased the 0 considerably. Contact angle, 0, increased considerably with increasing MgO particle size. SEM analysis showed deposition of glass phase was present at the interface as the finer MgO particles were used.

Jan 1, 2004

By L. V. Chugaev

In the course of the hydrothermal refining of copper-nickel products containing covellite, oxidation of Fe2+ ions by the CuS?Cu2+ pair takes place, and iron is precipitated as hematite. Lower copper concentrations in the solution and higher solution acidity lead to the partial oxidation of sulphide sulphur, whereupon hematite is reduced by covellite causing iron to go back in solution. It is demonstrated that in the process of hydrothermal treatment of the covellite-containing solid product in pure water covellite oxidises millerite to polydymite (Ni3S4). Formation of polydymite during the process of refining seems to be due to millerite oxidation both by covellite and the CuS?Cu2+ pair.

Jan 1, 2007

By N. Ntakaburimvo, C. Allaire

This paper presents an innovative experimental set-up which simulates refractory degradation by separate and simultaneous action of abrasion, erosion and partially or totally immersion corrosion whether dynamic or static. It also presents abrasion testing results obtained from five commercial aluminosilicate refractories used in aluminium melting and holding furnaces. Abrasion wear was quantified by measuring the weight loss and the depth of wear, as well as by determining materials properties degradation, such as the residual rupture force and the residual modulus of rupture. Results were correlated to as- fired materials properties, such as rupture force, flexural strength, elastic modulus, toughness, and apparent porosity; in order to establish which property could be used for refractory abrasion wear prediction. They were also related to the critical length of pre-existing defects and to those generated by the abrasion process. Positive correlation was established between abrasion resistance and mechanical properties, particularly for refractory castables. For similar mechanical strength, the castables tested offered less abrasion resistance than the brick sample.

Jan 1, 2004

By H. Ito, T. Takasu

A leaching process for recycling small car motor scraps dismantled from End- of - Life -Vehicles (ELV) was investigated using waste pickling acid in steel work. Steel parts of mortar scraps were leached by waste pickling acid and Cu wire was recovered as pure Cu in the process. Pickling acid solution after leaching could be recycled in an ordinary process for waste pickling acid solution. High grade FeSO4 agent could be produced using H2SO4 as a pickling solution.

Jan 1, 2004