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By A. R. Byers

"This paper describes the distribution, occurrence, and paragenesis of known sulphide deposits within an area bounded by longitudes 102°00' to 106°00' west and latitudes 54 ° 301 to 57 °00 1 north. The Precambrian bed-rock which outcrops over all but the southern fringe of the area con- . sists of regional metamorphic assemblages ranging from low grade or green schist facies to high grade or amphibolite-granulite facies. The areas . of low-grade metamorphism correspond to 'islands' of volcanic rocks which are surrounded by highgrade paragneisses and migmatites. Intrusive rocks range in composition from ultrabasic to granitic and may be divided into syntectonic and posttectonic sequences. The average composition of the former is granodiorite and of the latter quartz diorite.The massive sulphide deposits fall naturally on basis of mineral content into the following divisions: ( 1) pyrrhotite and / or pyrite, (2) sphalerite and/ or chalcopyrite plus iron sulphides, (3) sphalerite and galena, ( 4) sulphide-bearing pegmatite, and (5) nickeliferous pyrrhotite and / or chalcopyrite. The deposits of iron sulphides are ubiquitous. Ratio of pyrrhotite to pyrite is fairly constant for individual deposits, but their areal distribution appears to be independent of the nature of the enclosing rock and grade of regional metamorphism. All deposits containing ore-grade quantities of base metals have been concentrated at favourable structural locations. Copper-zinc and lead-zinc deposits appear to be associated with syntectonic granodiorite with the lead-zinc concentrations confined to calc-silicate gneisses. Copper-nickel deposits show a close relationship to post-tectonic gabbros and pyroxenites. The paragenesis is more or less the same for the majority of deposits, with iron sulphides and sphalerite being introduced early and followed by chalcopyrite and galena. Some vertical and / or horizontal zoning is apparent in a few deposits. Temperatures of formation and origin of the deposits are briefly discussed."

Jan 1, 1960

By E. C. Roper

THE Britannia Mining & Smelting Company, Limited, have been operating their property at Britannia Beach, B.C., continuously for nearly forty years and have mined over 33,000,000 tons of ore from orebodies within a belt of highly sheared rocks, five miles long by 2,000 feet wide. The property is in the Coast Range mountains, about twenty miles due north of Vancouver. The mountains rise abruptly from sea level to elevations of 4, 500 feet within a horizontal distance of 7,000 feet. The topography has enabled the orebodies to be developed by adit tunnels. The active mining levels are connected to the adits by incline and vertical service shafts. The main service adits are the 2200, 2700, and 4100 levels (see Figure 1). The mine surface shops, three bunk-houses, and over one hundred dwellings form the townsite camp at the portal of the 2200 level adit. A small camp of one bunk-house and a few dwellings is situated at the 2700 level portal. The beach surface shops and camp, adjacent to the 4100 level adit, service the mill, foundry, and other beach installations as well as the mining from the 4100 level. The ore mined from the various orebodies is delivered to the 4100 main haulage level through a system of rock raises and intermediate tramming levels and is hauled on the 4100 level to the mill.

Jan 1, 1945

By K. Lascelles

ABSTRACT Nickel compounds vary significantly in their toxicological properties, so it is critical that continuing studies to accurately quantify worker exposures consider the processing that accompanies refining nickel-containing materials. The Clydach nickel refinery, which has operated for more than 100 years, was the first nickel-producing facility to show a high risk for lung and nasal-sinus cancers among workers employed since it opened in 1902. Process chemistry and equipment have changed dramatically over Clydach’s history. This paper describes the processing evolution at Clydach with a focus on the propensity for aerosol formation and the forms of nickel in airborne dusts.

Jan 1, 2013

By E. B. Wilson

"Although the Operations Research technique of Reliability Theory has been applied with marked success in many fields, including the Apollo spaceship programs, the concept of reliability has not been generally adopted in mining and other heavy industries. Of course, reliability, or the probability that a system will be able to operate without a failure for a given interval of time, does not require the same emphasis in mining as in the aerospace industries. Nevertheless, certain aspects of Reliability Theory can be followed advantageously. For example, reliability calculations can determine the best time to overhaul and whether to retain stand-by units.The usefulness of the pseudo-operations research technique known as Replacement Theory is more readily re-cognized by the maintenance engineers in mining and other heavy industries. One of the least complex models enables the optimum Lifetime of an asset to be determined."

Jan 1, 1970

By R. F. Favreau, L. C. Lang

"In modern blasting technology blasts are designed and analysed on an energy-mass-time relationship. The energy of the explosive is derived by computer analysis and the work potential of the available energy is expressed in numerical values. The mass involved in the blast is determined by the geometry of the blast and by the rock density. Time is also a relevant parameter, because time is required to complete the three basic stages of the breakage process.For successful application of the blasting parameters the basic mechanism of the breakage process must be understood.The physical-mechanical properties of the rock, local structural geology and the thermodynamic properties of the explosives can be brought together to create a computer model of a blast with which it is possible to predict separately the results of each parameter and to express the predicted degree of change in any parameter by actual numbers.A long-range project has started to create a ""bank"" of rock properties for as many Canadian and foreign mines as possible. A computer model has been successfully applied to predicting the effect of varying the ratio of spacing to burden at constant rock volume and significantly improved results are achieved, as the S/B ratio is increased up to about 2 to 2.5.High-speed photography has been applied to determine the time that has elapsed between zero time and the beginning of movement of the mass. The results assist in determining minimum and optimum delay time required for multiple-row blasting.The approach as described in the paper is now well proven and is clearly superior to previous methods based on powder factors and human assessment."

Jan 1, 1972

By T. N. MacAuley

"The Ingerbelle and Copper Mountain deposits are located near Princeton in southern British Columbia. They are owned by Newmont Mining Corporation's wholly owned subsidiary, Similkameen Mining Company Ltd. The property includes the Copper Mountain mine, a former producer. Ore reserves recoverable by open-pit mining are estimated to be 76 million tons containing 0.53% copper. Production commenced during 1972 at a rate in excess of designed capacity (15,000 tpd). All of the known major copper deposits in this area lie in a 14,000- by 3,500-foot belt of Triassic volcanics (Nicola Group) that is situated between a well-defined syenitemonzonite- diorite stock on the south and a variable intrusive complex on the north. The Nicola rocks consist of andesitic tuffs and agglomerates with lesser amounts of flows and some lensy siltstone layers. The orebodies are essentially disseminated sulphide deposits, although fracture-fillings are also important in many areas. Total sulphide content is usually less than 5%. At lngerbelle, and at Pit 2 and most of Pit 1 at Copper Mountain, the sulphides are chalcopyrite-pyrite. In part of Pit 1 and most of the former underground mine they are chalcopyrite-bornite. At lngerbelle the predominant alteration associated with mineralization is a pale greenish-gray bleaching of the dark andesitic rocks. This has been identified as albitization, with lesser amounts of epidote, chlorite, biotite, scapolite and calcite. This bleaching is plentiful at Pit 2, but K-feldspathization is also evident here. These orebodies can better be classified with pyrometasomatic deposits than with typical porphyry coppers. Their relationship to intrusives, the probably extensive metasomatic replacements, the evidence of pneumatolytic activity, the formation and redistribution of magnetite, and the irregular distribution of mineralization are all characteristic of this class. Deep-seated faults probably acted as channelways for mineralization; fracturing, faulting and rock contacts influenced ore localization in detail."

Jan 1, 1973

"The QEMSCAN system is the third generation of automated mineral analysis systems that began with the QEM*SEM at CSIRO 30 years ago (Butcher et al. 2000). It is now a successful commercial instrument with 39 instruments in operation around the world. Back Scattered Electrons (BSE) and Energy Dispersive (EDS) X-Ray spectra are used to create digital mineral images with mineral identification occurring online. Low-count EDS spectra are used preferentially to BSE brightness, allowing minerals to be accurately identified by chemical composition. Individual minerals or groups of similar compositions are identified by comparison to a comprehensive mineral database incorporated into the QEMSCAN software. Optical mineralogy and Scanning Electron Microscopy is a metallurgists’ tool for determining the ore process mineralogy and delivering a better flowsheet. These techniques have limitations, provide limited information and sometimes fail to provide representative information. In contrast, QEMSCAN provides information on the nature and occurrence of all mineral species present plus the liberation characteristics, looking at thousands of particles in the sample presented. Some of the data presented includes:• Particle and grain sizes• Dominant mineral species• Particle shape• Calculated metal content• Density• Deportment of elements of interest between the mineral phases• Quantitative mineralogy• Mineral associations, locking and liberation• Textural relationships (particle images)It can also be used on concentrates, polished sections or drill core. This is a significant improvement in ore characterisation providing lithology, mineralogy, liberation, ore grade and porosity from a sample. Theoretical grade-recovery curves can be created to be mineralogically limited from QEMSCAN analysis which, when compared with metallurgical results, are valuable in evaluating whether liberation or chemical selectivity is driving flotation performance. A number of case study examples are given where the QEMSCAN had a significant bearing on future project development at an early stage of exploration and mine development."

Jan 1, 2012

By C. H. Wright

Introduction The rapidly expanding and increasingly complex Canadian industrial structure, with the mining, metallurgical, and chemical industries as a large integral part, has, in recent years, brought greatly increased importance and value to our industrial minerals. In the modern economy of our mineral industry the importance which is due the non-metallics has been somewhat overshadowed by the great value of our large metal production and, in addition, by the glamour and fascination usually associated with the mining and treatment of gold ores. The term 'Industrial Mineral' is used in this paper in its usual sense and refers to non-metallics other than fuels. Coal and petroleum products, including natural gas, are considered as industrial minerals in those applications in which they are used for strictly chemical process purposes. Certain reduction metallurgical industries are so closely allied to chemical industries that for purposes been of this discussion no attempt has made to differentiate between them. Chemical industry in Canada today is a fairly large factor in our national economy, whereas in 1898, when the Canadian Mining Institute was born, it was very small indeed. Chemical concerns are largely dependent on industrial minerals for raw materials and process supplies and, as the country has developed industrially, so have the demands for non-metallics increased, not only by chemical industry but also by other large consumers, such as the construction and metallurgical industries. At the present time there is a greater than normal incentive prevailing for new discoveries, due to the serious lack of balance that exists in our import and export trade. This fact has resulted in intensive efforts to rectify the situation by locating new deposits and re-assessing those already known in an effort to enlarge and improve our home production of raw materials and also to extend their processing in Canada for our own needs and for export. The rapid advances in science and technology that have taken place since 1900 have also resulted in many cases of beneficiation and utilization of otherwise too low grade materials in order to satisfy current demands. The purpose of this paper is to indicate the history and the trends of the utilization of industrial minerals in established industry and to indicate the important part played by non-metallics in connection with the opening up of new industries. Some consideration has been given to the continual competition between natural and 'synthetic products and to the general tendency towards more rigid specifications.

Jan 1, 1948

By J. R. Levin, E. J. Schelter

"We present some of our recent efforts in the development of predictive, directed oxidation chemistry of cerium(III) complexes under non-aqueous conditions. The electrochemistry of cerium(III)- alkali metal heterobimetallic aryloxide complexes is reported and compared with cerium aryloxide complexes that are kinetically stabilized by hydrogen bonding cations that span between the complexed aryloxide ligands. Comparative electrochemical measurements reveal differences between the heterobimetallic complexes and the hydrogen-bonded complexes.INTRODUCTIONThe rare earth elements comprise the lanthanides, La–Lu, and the element yttrium (Aspinall, 2001). Rare earth ores such as monazite, LnPO4, and bastnäsite, LnFCO3, typically bear mixtures of light rare earths: La–Sm while monazite, LnPO4, contains mixtures of heavy rare earths (Eu–Lu) (Cotton, 2006). Pure rare earth elements typically are isolated using a liquid-liquid separations process.(Bautista, 1995) The hydrometallurgy of these elements is a difficult problem because the separation factors between neighboring rare earths, which are predicated on the small differences in the sizes of the trivalent ions, are quite small (Cox, 1992). The element cerium, with its 4f1 electronic configuration in the trivalent state, is unique among the rare earth elements due to a relatively accessible 4f0 electronic configuration. The accessibility of the 4f0 configuration underlies the chemistry of cerium(IV), the only rare earth ion with molecular chemistry in the tetravalent oxidation state (Cotton, 2006). Cerium is trivially separated from mixtures of light rare earths by making use of its unique oxidation chemistry. In an effort to extend separations chemistry by oxidation reactions to other rare earth elements such as terbium and praseodymium, the solution electrochemistry of well-defined cerium complexes is of interest."

Jan 1, 2012

By B. S. Ignasiak, Dennis Carson

"Laboratory study of the behaviour• of binary coal blends shows that coke strength is more closely dependent on the distribution of ""reactive"" oxygen in the parent coals than on their proximate, elemental or petrographic compositions, and it also appears possible to qualitatively predict coke strength from information about reactive oxygen. Proceeding from this recognition, experiments were carried out to test the possibility of preparing metallurgical cokes from binary blends in which non-caking hvb coal was substantially freed of reactive oxygen by prior heat t1•eatment under controlled conditions. The results indicate that such blends can yield surprisingly strong cokes and that coke strength may be amenable to further improvements by modifying the size distribution of the pre-heated component and the rate at which it is charred."

Jan 1, 1976

By Stephan I. Zajac, Roger A. Blais, John B. Stubbins

THE iron deposits of central Labrador occur within a relatively small area, herein called the Knob Lake Iron Range, in which a northwest-trending series of low hills and ridges defines the height-of-land at the boundary between provinces of Quebec and Newfound-land. Approximately two-thirds of the deposits are in Quebec and the remainder in Labrador, with several deposits straddling the inter-provincial boundary. These deposits are being exploited in open-pit mines by the Iron Ore Company of Canada centered at Schefferville, Quebec. Since 1954 this company has produced more than 56 million tons of iron ore to become Canada's leading iron ore producer. With indicated reserves of more than 375 million tons of direct-shipping ore and large tonnages of iron formation amenable to beneficiation, this mining district is assured of a long life. This paper describes the Knob Lake iron ores and their geological settings and stresses the features that lead to a better understanding of their origin. The

Jan 1, 1961

By A. N. Shen

Fe3A1 intermetallics are potential inexpensive candidate for hot applications. In this project, torsion tests on hot-rolled and annealed Fe3A1 (Fe-15.5A1-5.8Cr-1.0Nb¬0.05C) were carried out over the ranges 750-950°C and 0.01~1s-1 . The experimental results showed that when peak stress op>90MPa (LogZ>16s-1 , Z: temperature-compensated strain rate), specimens cracked at randomly low strains. Optical microscopy exhibited original elongated grains and many grain boundary cracks associated with segregation. With op<40MPa (LogZ<16s-&apos;), specimens deformed with low random op but considerably high fracture strains; slowly propagating cracks may explain the reduced flow stress. Optical microscopy showed both elongated grains and equiaxed subgrains with some indications of geometric dynamic recrystallization (gDRX) and of static recrystallization (SRX). Compression tests gave higher stress with little effect of the preexisting cracks. The activation energy Quw of current material in satisfactory torsion and compression tests is about 10% higher than previously published. Fe3A1 has body-centered cubic structure in the experimental range, so it was compared with ferritic stainless steel 434C (Fe- 16.55Cr-0.96Mo-0.21Ni). Constitutive constants and restoration mechanism are compared between these materials. While Fe3A1 is hardly a light metal, it is considerably lighter than most steels. Furthermore, like the other body centered cubic metals (BCC) (a-Fe, ß-Ti, ß-Zr and ß-brass), it exhibits a high degree of dynamic recovery (DRV) like Al alloys, producing easier hot workability than that of austentic stainless steels.

Jan 1, 2007

By James E. Wennen

The through-put and energy efficiency of an autogenous (AG) grinding mill are adversely affected by variability in rock size and rock competency. This applies to both fully autogenous and semi-autogenous (SAG) grinding circuits. In this paper we focus on an approach to overcome the problem of inconsistent mill through-put related to variability in mill feed size and rock competency. The focus is on ores containing hard, competent rock. This approach consists of preparing feed to an autogenous mill that contains 20% coarse media rock and 80% of material crushed to pass 37 mm. Results of pilot-scale testing for two iron-ores will be presented to show that a 10% to 12% reduction in unit energy consumption is possible with prepared feed, compared with feeding the mill with conventional primary crusher discharge.

Jan 1, 2012

The JKRBT (JK Rotary Breakage Tester) is a newly developed impact breakage testing device for rapid ore breakage characterisation, and has recently been commercialised after a three year comprehensive validation study, involving five major mining companies and six industrialised JKRBT units deployed worldwide. Comparisons of breakage mechanisms and characterisation data between the JKRBT and the Drop Weight Tester (DWT) indicate that, despite the differences in the breakage modes, the JKRBT can provide statistically similar A*b parameters, by using a data reduction procedure which takes into account the difference in the number of contact points, strain rate and potential for secondary breakage. Feedback from the validation sponsors has indicated higher productivity and better repeatability of the JKRBT compared with the DWT. This better precision, combined with the JKRBT?s wider particle size capability and wider specific energy range, provide a more powerful tool, ideally suited to rapid mapping of ore hardness in geometallurgical and comminution applications.

Jan 1, 2012

By Keith Haddock

"The Sheerness Mine, a new surface coal mine located near Hanna, Alberta, went into full production in mid-1995. The mine, which is operated by Luscar’s subsidiary Forestburg Collieries (1984) Ltd., has the design capacity to supply up to 2.1 million tonnes of sub-bituminous coal per year to the adjacent Sheerness Generating station under a 30-year contract. This paper documents the construction phase of this project and highlights the major equipment purchases as well as the construction of the mine facilities. The paper also focuses on some of the areas where cost savings have been achieved that have allowed the mine to come on stream six months ahead of schedule, and under budget. Project ReviewMine DescriptionThe Sheerness Mine is located 25 km southeast of the town of Hanna in southeastern Alberta (Fig. 1). The mining property occupies the western portion of the Sheerness CoalField and borders the Montgomery Mine, operated by Manalta Coal Ltd. in the east, and Highway 36 in the west. The Montgomery Mine and the Sheerness Mine exclusively supply the total coal requirement of the adjacent Sheerness Generating Station. The station is owned jointly by Alberta Power Limited (APL) and TransAlta Utilities Corporation (TAU). APL is the operator. Manalta’s Montgomery Mine has supplied coal to the Sheerness Station since its opening in 1986. Coal is shipped by truck from the mines over a network of haul roads to the coal receiving hoppers located on the east side of Highway 36."

Jan 1, 1997

By David Sanscartier, Elizaveta Petelina, Alexey Klyashtorin

This paper provides an overview of the radiological risk mitigation approach applied by the Saskatchewan Research Council (SRC) for the remediation of 35 legacy uranium mine sites in northern Saskatchewan where uranium exploration and extraction took place in the 1950–60s. Mining activities resulted in an irregular increase of the gamma radiation dose rate (up to 18 μSv/h). The radiological objectives for the sites include a gamma dose rate at a spot (<2.5 μSv/h above local background), and the dose rate averaged over a hectare (<1 μSv/h above local background). These objectives are generally achievable at the impacted sites through the installation of shielding soil cover. This method may be impractical for site areas with rough terrain (e.g., steep slopes) and/or difficult access. A risk assessment approach is applied to determine if these areas can be safely left uncovered or if additional mitigation measures should be implemented. The risk assessment approach is based on two factors: (i) the ambient radiation dose rates collected through gamma surveys, and (ii) actual land use data collected through various surveys of activities of local community members at the sites. Exposure scenarios based on four land uses are applied to estimate a potential annual dose load for members of the public. The estimated doses are compared with the criterion of 0.3 mSv/a recommended by the Canadian Guidelines for the Management of Naturally Occurring Radioactive Materials (NORM). If the criteria are not satisfied, a mitigation plan is developed, and post-remediation gamma levels are modelled using GIS tools to evaluate the performance of the proposed mitigations. The proposed approach allows the team to optimize resources for the site remediation so that public exposure to NORM are as low as reasonably achievable after remediation.

Jan 1, 2020

By Ltd. (CYMCO) Technology Center Yunnan Metallurgical Group Co., S. Jian, T. Song, J. D. Miller

"As sulfide zinc ore deposits become exhausted, nonsulfide zinc ore deposits become the other resource for zinc production. However, flotation for zinc recovery from nonsulfide deposits is much more difficult than the flotation of sphalerite from sulfide deposits and may become an option for zinc production only if a suitable processing technology is developed. In this regard, research efforts are being devoted to the flotation of nonsulfide zinc oxide minerals. Some common methods which have been used for the flotation of zinc oxide minerals include sulfidization-flotation, activation, and direct flotation with anionic and cationic collectors. The traditional flotation techniques have low efficiency and difficulty in separation and recovery of the zinc minerals from gangue minerals, for example, smithsonite (ZnCO3) from other carbonate gangue minerals and hemimorphite (Zn4Si2O7 (OH)2·H2O) from silicate gangue minerals. In this study potassium lauryl phosphate was evaluated as a collector for the flotation of nonsulfide zinc minerals. Results from contact angle and microflotation experiments at pH 6–9 show that hemimorphite (Zn4Si2O7 (OH)2·H2O) can be floated from quartz and that smithsonite (ZnCO3) can be floated from calcite. However, when dodecylamine, which is a common collector reported in literature for the flotation of nonsulfide zinc minerals, was used as collector, no significant difference between nonsulfide zinc minerals and gangue minerals was observed at any pH value. Initial evaluation suggests that potassium lauryl phosphate is effective at low concentration and may be a promising collector for zinc oxide mineral flotation.INTRODUCTIONBefore the twentieth century, zinc was mainly produced from nonsulfide ores (Large, 2001; Gilg, Boni, & Cook, 2008). With the development of differential flotation processes in the late 19th century major production switched from nonsulfide zinc sources to sulfide zinc ores (Hitzman, Reynolds, Sangster, Allen, & Carman, 2003; Gilg et al., 2008). However, as it is becoming more difficult to find new sulfide ores, recovery from nonsulfide deposits is being considered. Nonsulfide flotation for zinc recovery is much more difficult than the flotation recovery of sphalerite from sulfide deposits and may become an option for zinc production if a suitable technology is developed. Zinc and lead oxide ores are difficult to beneficiate ores due to their similar floatability with gangue, high solubility in water, and the influence of slimes (Fa, Miller, Tao, & Li, 2005). In order to improve the performance of oxidized minerals, lots of effort is being devoted to this field of study (Ejtemaei & Mahdi, 2014)."

Jan 1, 2016

By T. Majcherczyk

Shaft lining reinforcing analysis of two shafts under construction has been presented in this study. The first shaft was driven from the surface, while the second was deepened. Mining and geological conditions have been studied with respect to the lining capacity. The improvement of shaft stability comprised two elements, i.e. reinforcement of the shaft lining capacity and improvement of the strength properties of the rock mass. In both tested cases, the particular hazard was connected with non uniform loadings of the lining, which could generate shearing stresses within lining structure. Thus such elements as armored concrete with high strength properties, bolting and injection sealing of the rock mass, and the use of special ring reinforcing the shaft lining have been used in order to reinforce the shaft-rock mass system. Practical conclusions related with new technological solutions, allowing the rock mass and shaft lining reinforcement, have been included for the present study. Practical conclusions related with new technological solutions, allowing for rock mass and shaft lining reinforcement, have been also included to the present study.

Aug 1, 2013

By Maurice A. Roche

Introduction Most of the Flin Flon ore-body, like many others in northern Canada, was covered by water. The original discovery was made where the ore-body outcropped on a strip of land jutting out into Flin Flon lake. The outcrop could be traced for a distance of 600 feet across the strip of land, but disappeared under the lake on both sides of the peninsula. Following the discovery or location of the property, in 1915, and subsequent to its examination by the H.P. Whitney interests in 1925, an extensive diamond-drilling programme was completed, which proved the existence of an ore-body at least 2,600 feet long and 900 feet deep. In plan, the central part of the ore-body at surface attains an overall width of about 450 feet; including waste horses, and gradually becoming narrower to the south. To the north, it stretches out as a much narrower tongue. The main body is a solid sulphide ore containing gold, silver, copper, and zinc. Adjacent to, and on the footwall side of, the solid sulphide ore-body, there are considerable widths of talcy disseminated copper ore, particularly in the upper 300 feet of the deposit, where the maximum widths occur. The ore-body occurs in a greenstone area, the rock being quite hard on the hanging-wall side, with the footwall schisted, talcy, and much softer. The greater part of the ore-body was overlain by 12 to 15 feet of water and from 15 to 90 feet of mud and clay, this material requiring eventual removal, regardless of the system of mining adopted. The total of mud and clay overburden was estimated at 1,000,000 tons. After considerable study, it was decided to mine the upper 300 feet of the ore-body by open-pit methods; the balance of the ore to be recovered by underground mining . The present paper gives an account of the methods adopted in both operations, and of the problems encountered.

Jan 1, 1935

By F. Rivard, M. G. Drouet, W. S. Ruff, P. Carabin

"In both the hot rotary-salt-furnace (RSF) treatment of aluminum dross and the cold ball-millsieving (BMS) treatment of zinc dross, enormous amounts of energy and recoverable metal are wasted and large amounts of greenhouse gas are produced. Such wastes and the environment pollution could be avoided by using the DROSRITE PLUS™ technology. Economic and GHG production comparisons between the presently used industrial treatment processes and DROSRITE PLUS™, supported by over one hundred tests conducted in Canada, the US and Europe, are presented. The savings, with DROSRITE PLUS™, would be about $191 and $418 per MT of aluminum and zinc dross, respectively.INTRODUCTIONDross is a material, which forms on the surface of molten non-ferrous metal, such as aluminum or zinc, during melting, metal holding and handling operations when the molten metal is in contact with a reactive atmosphere. Dross normally consists of metal oxides entraining a considerable quantity of molten free (unreacted) metal, and for economic reasons it is desirable to extract the free metal before discarding the residue. In the case of aluminum dross, recovery of the metal is usually carried out by treating the dross in a furnace at a high temperature (Peterson et al., 2002). By contrast, cold zinc dross is crushed in a ball mill followed by sieving to separate the coarse metal portion from the fine oxide residue.The conventional aluminum dross treatment process, using gas or oil-heated rotary salt furnaces (RSF), is thermally inefficient and environmentally unacceptable because of the salt slag and CO2 produced from the combustion of fossil fuels. In the past several years, a number of salt-free processes have been developed and some of these have found limited commercial use (Gripenberg et al., 1994; Lavoie et al., 1990). In all these dross treatment processes, heating of the cold dross in a rotary furnace requires an external energy input that varies between 375 and 2,500 kWh per (metric) tonne of dross. Molten metal separated during processing of the heated dross is tapped, and the remaining solid residue is discharged from the furnace."

Jan 1, 2012