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By J. Fellowes, Z. Liang, J. Robson, M. Kenyon

"Dispersoids play a significant role in the recrystallization and texture development for wrought Al-Mg-Si (6xxx series) alloys by inhibiting grain boundary motion. It is therefore important to understand the precipitation kinetics of such particles. It is the additions of Mn and Cr in Al-Mg-Si based systems that can lead to dispersoid phases being formed. These phases are currently thought to nucleate on ß’-Mg2Si via an intermediate semi-coherent precipitate. Scanning transmission electron microscopy (STEM) has been conducted to study the precipitation of a-Al(CrFe)Si and a’-AlCrSi dispersoids. Corresponding electron dispersive spectroscopy (EDS) has been used to distinguish the dispersoids. The volume fraction and size distribution of dispersoids has been measured as a function of distance across a grain. Electron probe microanalysis (EPMA) has been conducted to study the inhomogeneity of elements in the cast structure and the effect on dispersoid precipitation. Dispersoid free regions have been observed in the microstructure correlating to regions depleted in the dispersoid forming elements.INTRODUCTION Al-Mg-Si (6xxx series) based alloys are increasingly being used in the automotive industry. The primary reason is to reduce the weight of vehicles, resulting in a reduction of CO2 emissions and increased fuel efficiency. The demand for 6xxx series is predicted to increase over the coming decade. Due to the high cost and CO2 emissions produced by raw extraction of aluminium, close loop recycling of these alloys becomes a more important process. However recycling of automotive alloys can be difficult due to pick up of impurity elements such as Mn, Cr and Fe. The addition of these elements can form dispersoid particles during early heat treatment processes. Although a controlled population of dispersoids is necessary to control the grain structure during thermo-mechanical processing, a significant change to the dispersoid population due to a composition change could profoundly influence the final microstructure, affecting the final properties of the material. More research is required on the precipitation and effect of additional minor alloying elements; in order to increase the 6xxx series alloys recyclability."

Jan 1, 2018

CONSTRUCTED WETLANDS (CWs) ?Human-Constructed ?Built Specifically to Remove Contaminants ?Can Treat a Wide Variety of Wastewaters Including Stormwater(SW) ?Three Major Kinds ?Pond Wetlands ?Free Water Surface Wetlands (FWS) ?Sub-Surface Flow Wetlands (SSF) ?HSSF & VSSF

May 1, 2009

By Bordeaux Sciences Agro-INRA UMR 1065 SAVE, S. Piutti, E. Benizri, S. Lopez

Ultramafic soils display high concentrations of nickel (Ni) and a number of nutrient deficiencies (e.g. N, K, P). Ni-hyperaccumulator plants have evolved on such environments, developed specific metal homeostasis showing concentrations of Ni sometimes above 1% in their aerial biomass (Baker & Brooks 1989). Alyssum murale, a Ni-hyperaccumulator, is commonly found around the Mediterranean but can grow on non-ultramafic soils as well, with an altitudinal extension ranging from sea level to 2000 m.a.s.l. Rhizosphere bacterial communities associated with Ni-hyperaccumulator plants can differ from those of non-accumulating plants growing at the same site. Among edaphic factors that could influence the phylogenetic structure of the bacterial communities, altitude and metal-bioavailability and in particular nickel could be significant. However, most studies have focused on analyzing soils with techniques that provide little detail about the phylogenetic structure of these bacterial communities present in ultramafic soils. The objectives of this study were to understand the specific changes in the structure of A. murale rhizosphere bacterial community that occur across two gradients: 1°) elevation and 2°) Ni geochemistry, using pyrosequencing technique (454-pyrosequencing of 16S rRNA gene). It was found that the higher the soil chemically-available Ni contents, the higher the relative abundance of Proteobacteria and Actinobacteria. On the contrary, the abundance of TM7 decreased with increasing levels of available Ni. Moreover, Chloroflexi was present with 53 to 77% of relative abundance. These results demonstrate that soil chemically-available Ni drives the bacterial community diversity in the rhizosphere of Alyssum murale regardless the elevation gradient and other different soil physicochemical parameters. These results should now be confirmed in different ultramafic edaphic environments worldwide (e.g. ultramafic lateritic covers) and in the rhizosphere of different hyperaccumulator taxa.

Jan 1, 2016

By Mark Holdsworth

In 2002, Kennecott Utah Copper Copperton Concentrator installed an Expert Control system for optimization of their SAG and Ball milling circuits. The advanced process control has been well received and is utilized well over 95% of the time. In the years since, many lessons have been learned and many advances have been made. Improvements have produced millions of dollars of benefits and have included directly controlling feedrate with complex logic as opposed to using a bearing pressure controller, modifications to how sound is used for control, modifying logic for maximizing asset utilization and using advanced control for automating equipment restart.

Jan 1, 2012

By R. Glenn Madill

Western Canada is defined, for the purposes of this paper, as that part of the Dominion bounded approximately by the 95th and 141st meridians of longitude and the 49th and 80th parallels of latitude. It is comprised of Manitoba, Saskatchewan, Alberta, British Columbia, Yukon, and that portion of the Northwest Territories lying to the west of the 95th. meridian. The first magnetic observations made in Western Canada were in the interests of navigation by sea. Observations were made by Captain Middleton in Hudson bay at Churchill and York Factory in 1725, and along the Pacific coast by Captain Cook in 1778 and Captain Vancouver in 1792. The first systematic magnetic survey in Western Canada was made between 1819 and 1826 by Sir John Franklin in his widely distributed explorations. It is of interest to find that while the first magnetic declination observations made in Hudson bay and along the Pacific coast were purely in the interests of navigation, the next investigations, which were made in the Western Arctic, included measurements of inclination and force with those of declination. There was a valid reason for this more complete research into the magnetic field as the construction of declination charts depended on the position of the north magnetic pole. Halley promulgated a theory 1683 that " the globe of the Earth may be regarded as one great magnet, having four magnetic poles, two of them near each pole of the equator, and that in those parts of the world which lie near any of those magnetic poles the needle is chiefly governed thereby, the nearest pole being always predominate over the more remote" . The position of a magnetic pole may be defined as a point where the inclination is 90 degrees and the horizontal force zero. It is obvious that the position cannot be' defined by declination observations alone since, for some distance from the magnetic pole, .the horizontal force is too weak to give directive force sufficient to effect the pointing of a compass.

Jan 1, 1948

By A. G. Doll

"This paper expands the SAG mill survey database published by the Author at Procemin 2013. The new database includes 49 published SAG/AG mill surveys and includes mills from all over the world. The paper will compare the survey database to SAG mill models by Austin, Morrell and Hogg & Fuerstenau with the purpose of demonstrating the degree of fit of the models to surveys and validating any empirical “fitting factors” used in the models.SAG mill power draw models are used in mill design and grinding circuit modelling to predict how much power will be consumed by a particular mill geometry and operating configuration. The importance of conducting surveys suited to model calibration will be highlighted because the review of literature shows that survey information important to modelling is often missing or omitted. A recommendation for the collection of data during a mill survey is presented, along with some assumptions used by the Author in the absence of certain data. The benefit to mining companies of publishing their survey data, and thereby allowing modellers to improve their model calibration, is discussed.The comparison of models requires a discussion of the measurement of power in a mill drive system as the models use slightly different position in the electrical network for ""where power is measured"". The benchmarking of models against plant operations requires a similar discussion of power measurement."

Jan 1, 2016

By G. S. Hume

In the transformation of carbonaceous materials, such as peat, to coals of various grades, the changes are known to be both physical and chemical and the grade of coal finally produced depends on the stage to which alteration proceeded. Those changes, which are frequently spoken of as the results of metamorphism, are due to pressure with accompanying heat and, according to the amount of metamorphism to which the sediments with the included carbonaceous beds have been subjected, there is a gradation from peat to anthracite coal, and even to graphite. The improvement in the quality of the coal as a result of metamorphism is due to an increase of the carbon content of the coal and a corresponding loss of the volatile materials. This rise in the quality of the coal according to the degree of metamorphism is well illustrated by the coals of western Canada. In the Plains area, where the deformation and the attendant metamorphism of the sediments is comparatively small, the coals are lignites, whereas in the mountains, where deformation has been severe, the coals are semi-anthracites. Sub-bituminous and bituminous coals occur in the intervening areas. The same general relationship between the quality of the coal and the degree of metamorphism holds true for the Appalachian basin of the United States, where there is a progressive improvement in the quality of the coals from west to east, that is, from an area of comparatively slight metamorphism to an area of marked deformation in the Appalachian Mountain region. But while it is true that this relationship holds in a general way, it has been found that the improvement in the quality of the coal is not always uniformly progressive, and there may be local variations such that an area containing coal with a carbon content indicating low or medium metamorphism may be surrounded by areas in which the coals are of higher grade. These local variations in many cases can be explained, and they in no way detract from the general rule that, in a region exhibiting a progressive betterment in the quality of the coal from an area of low metamorphism to one of more marked deformation, the quality of the coal, i.e., the amount of fixed carbon in the coal, may be taken as an index of the degree of metamorphism of the coal as well as of the sediments in which it occurs, It has been pointed out (') that certain coals, such as cannels, are unreliable indicators of the varying degree of metamorphism because of the nature of the material from which such coal was derived. Such coals, however, are not known in western Canada and their behaviour need not here be discussed.

Jan 1, 1927

By N. E. Izatt

Molecular recognition technology (MRT) has a wide range of applications in the hydrometallurgical and chemical processing industries for the selective removal of iron as well as various other impurities from a variety of streams, including aqueous solutions through a wide pH range, as well as organic solutions. An example of a commercial application is provided for the removal of iron from an aluminum chlorohydrate stream. In this example, MRT has a selectivity for iron relative to aluminum which is significantly higher than that of ion exchange resins. A discussion of MRT capabilities for other impurities and streams is also provided.

Jan 1, 2006

By T. H. Wilson

In 1901, the Crow's Nest Pass Coal Company, Limited, began producing industrial coke in 212 beehive ovens at Michel colliery. By 1908, 486 ovens had been installed and in that year 147,623 tons of coke were produced. Coke manufacture has been continuous from 1901 until the present time (1946), with total production of 2,795,402 tons. At present writing, only 100 beehive ovens are operating and production is reduced to 1,800 tons per month, due to the shortage of suitable labour. These ovens are drawn by hand, on contract, and the workmen are exposed to considerable heat. A man draws three ovens in eight hours, thereby producing approximately 1072 tons of coke per day. In addition to the inefficient and costly method of drawing coke in beehive ovens, tremendous losses are experienced in the wastage of gas and tar, which are driven off into the atmosphere. Also, the yield of coke per ton of coal fed to the ovens is low as part 9f the carbon is utilized in producing heat to carbonize the remainder of the coal. A recovery of only 55 per cent of the carbon, as coke, is obtained. The coking process takes place from the top of the charge, which is 21/2 feet deep, downward to the floor. Six and a half tons of coal are charged and 3.6 tons of coke are drawn from the oven after 72 hours' carbonization. The beehive ovens using Michel coal produce a very hard and tough coke, large in size and of silvery appearance, which has served the requirements of both foundry and smelter for many years. In 1938, the Company made a careful study of coking processes with a view to introducing a more economical method than beehive ovens and one that would be less dependent on skilled labour, the supply of which was rapidly diminishing at that time. Various methods of by-product coking were investigated, and it was decided that the Curran-Knowles process offered the greatest possibilities because of the low capital investment in relation to output and also because the horizontal oven design was suitable for an expanding coal. Consequently, a test on Michel B seam coal, supervised by Mr. E. Burrough, of the Fuel Research Department, Ottawa, was run in the Curran-Knowles plant at West Frankfurt, III. The results of this test led to the construction of a ten-oven battery of 32 ft. 6 in. by 8 ft. 3 in. Curran-Knowles ovens at Michel, which were completed in November, 1939. This battery was built as an experimental unit, with provision for an additional ten ovens if the coke proved satisfactory for the market. In 1942, an expanding coke market led to the construction of a second battery of ten ovens, which were completed in April, 1943.

Jan 1, 1947

By Robert B. Parsons

"Starting January 1, 1987 employers, employees, and other taxpayers are confronted with a new set of rules dealing with the taxation of travel and housing benefits relating to isolated posts in Canada, and tax deductions relating thereto. The new rules may not be the simplest in the world, but they are reasonably fair and at least offer a hitherto unknown degree of certainty as to how such allowances are to be treated. IntroductionThe first shoe fell on February 26, 1986 when Finance Minister Michael Wilson' s first budget presented the framework for the future tax treatment of travel and housing benefits (so-called ""northern allowances"") provided to residents in remote regions of Canada. The second shoe fell some ten months later on December 22, 1986 when the Minister of Finance filled in the earlier announced framework with detailed rules. We now have a complete picture of the tax treatment of northern allowances. Here is what the picture looks like with effect from January 1, 1987.According to Revenue Canada, the net housing benefit to employees will be equal to the value of the accommodation provided, less any rent they have paid. In major centres such as Yellowknife and Whitehorse, having a developed rental housing market, the benefit amount will be based on the fair market value of the rental accommodation in that location. In other areas, employers will be required to value the housing benefits and, to assist employers, Revenue Canada has provided the following guidelines: Common shelter- $100 per month including the value of subsidized utilities Apartment! duplex-$270 per month excluding the value of subsidized utilities, or $400 per month including the value of subsidized utilities House-$450 per month excluding the value of subsidized utilities, or $650 per month in- c1uding the value of subsidized utilities.The amounts established as the values of accommodation will be adjusted annually after 1987 based on the housing component of the Consumer Price Index."

Jan 1, 1987

By E A. Mitchell

In the fall of 1961, Cominco dis-carded its long-established system of feeding the lead blast furnaces by narrow-gauge tram and V-cars, and installed an elevated monorail bucket system. This system automatically loads buckets of sinter, along with the correct proportion of coke, and delivers them to any of several designated furnaces. Direct labour usage has been reduced by nine men per day; improved coke proportioning has been achieved; and a major safety hazard has been eliminated. Introduction I N THE fall months of l 961. the system of feeding the lead blast furnaces at the Trail, B.C., smelter of The Consolidated Mining and Smelting Company of Canada Limited was altered from the tradition-al narrow-gauge railway and V-car method to one employing mono-rail carriers. The change was in keeping with a recent trend at Trail to replace narrow-gauge tramming with alternative methods of materials handling. In the case of the blast furnace feeding, the

Jan 1, 1963

"The Companion Policy is guidance and not law. It sets out the views of the Canadian Securities Administrators (CSA) at to the manner in which the CSA interprets and applies certain provisions of NI 43-101 and Form 43101F1. The Companion Policy references the CIM Best Practice Guidelines for Mineral Exploration, and the Mineral Resources and Mineral Reserves, and that they should be followed by Qualified Persons.COMPANION POLICY 43-101CP TO NATIONAL INSTRUMENT 43-101 STANDARDS OF DISCLOSURE FOR MINERAL PROJECTS This companion policy sets out the views of the Canadian Securities Administrators (the “CSA”) as to the manner in which the CSA interprets and applies certain provisions of National Instrument 43-101 and Form 43-101F1 (the “Instrument”), and how the securities regulatory authorities or regulators (the “Securities Regulatory Authorities”) may exercise their discretion in respect of certain applications for exemption from provisions of the Instrument. PART 1 APPLICATION AND TERMINOLOGY 1.1 Supplements Other Requirements – The Instrument supplements other continuous disclosure requirements of securities legislation that apply to reporting issuers in all business sectors. 1.2 Evolving Industry Standards and Modifications to the Instrument- Mining industry practice and professional standards are evolving in Canada and internationally. The Securities Regulatory Authorities will monitor developments in these fields and will solicit and consider recommendations from their staff and external advisers as to whether modifications to the Instrument are appropriate. 1.3 Application of the Instrument -The definition of “disclosure” under the Instrument includes oral and written disclosure. The Instrument establishes standards for disclosure of scientific and technical information regarding mineral projects and requires that the disclosure be based on a technical report or other information prepared byor under the supervision of a qualified person. The Instrument does not apply to disclosure concerning petroleum, natural gas, bituminous sands or shales, groundwater, coal bed methane or other substances that do not fall within the meaning of the term “mineral project” in section 1.1 of the Instrument. 1.4 Mineral Resources and Mineral Reserves Definitions - The Instrument incorporates by reference the definitions and categories of mineral resources and mineral reserves as set out in the Canadian Institute of Mining, Metallurgy and Petroleum (the “CIM”) Definition Standards on Mineral Resources and Mineral Reserves (the “CIM Definition Standards”) adopted by the CIM Council on November 14, 2004, as amended. 1.5 Best Practices Guidelines for Mineral Resources and Mineral Reserves - A qualified person classifying a mineral deposit as a mineral resource or mineral reserve should follow the CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines adopted by CIM on November 23, 2003, as amended. These guidelines are posted on www.cim.org."

Jan 1, 2003

By H. V. Kinsey

"IntroductionTITANIUM is probably the most widely publicized metal today. Much has been written, both in the lay press and the technical press, about its properties and potentialities. In view of the fact that Canada possesses large quantities of titanium-bearing ore, and could conceivably become a major producer of metallic titanium, it was felt that a paper dealing mainly with the physical metallurgy of titanium would be of interest to this Institute. This paper is concerned chiefly with the useful properties of titanium and its alloys and the fundamentals governing the modification of its properties by alloying.Physical Properties of TitaniumTitanium belongs to a family of metals that have been termed 'gas sensitive' (I), because their mechanical properties are altered by certain gases which they readily absorb and retain. Other metals of this group are zirconium, hafnium, vanadium, columbium, tantalum, and chromium. Titanium has a strong affinity for oxygen and nitrogen and once it has absorbed these gases they cannot be removed either by melting in vacuum or by any degassing agent. These gases, when present in excess of about half a per cent oxygen plus nitrogen, render the metal brittle and useless as a structural material.Some of the typical physical properties of titanium are listed in Table I along with those of common structural metals for comparison."

Jan 1, 1953

By F. L. Casey

"Part 1 – Published Papers Baria, G., and Boshkov, S., ""Insights into Undercuttingin Block Caving"", Proc. 5th Rock Mech. Symp.,Mines Br. - Information Canada, 41-58, 1970.Barron, K., Coates, D. F., and Gyenge, M., ""ArtificialSupport of Rock Slopes'', Mines Branch ResearchReport R228, July, 1970.Barron, K., ""Criteria for Brittle Fracture Initiation inand Ultimate Failure of Rocks and Their Applicationto Fracture Zone Prediction"", Proc. 2ndCongr. Int. Soc. Rock Mech., Belgrade, 1970, 3-37.Bauer, A., and Calder, P. N., ""Projectile Penetration inRock"", Proc. 5th Rocle Mech. Symp., Mines Br. -Information Canada, 157-170, 1970.Bauer, A. M., ""Site Development and Rehabilitation ofPits and Quarries"", Canadian Mining Journal,Vol. 91, No. 7, 77, July, 1970."

Jan 1, 1971

By Humphrey Dean

"Canadian mining companies now operate numerous Koepe-type friction hoists in a variety of different shafts, most of which have a depth in excess of 3,000 feet. Rope performance reliability is an absolutely essential ingredient of most installations and, for this to be provided, a more comprehensive understanding of rope reactions to applied stresses is required.It is the intent of this paper to illustrate for the operators the importance of the critical stresses encountered and to provide a maintenance program designed to circumvent potential difficulties."

Jan 1, 1970

By J. P. Piguet, A. Hosni, J. P. Josien, H. Baroudi, R. Hadadou

"The iron ore mines in the Lorraine region of north-eastern France cover a surface area of approximately 3,900 km2 and involve more than 150 cities. A total extraction method was usually used during exploitation, but this technique was sometimes replaced by the room and abandoned pillar technique when it was necessary to protect surface buildings and infrastructure. Rooms and abandoned pillars were initially designed to ensure long-term mine stability. However, this aim was not always reached and numerous collapses occurred in the Lorraine iron basin, either during production or several years after closure. Several subsidence events were identified during a period of one century; the most recent event occurred in 2012. Two groups of events were identified. The first group represents events characterized by sudden surface movement, and the second group includes event characterized by progressive subsidence.Numerous studies conducted during the last decade helped improve our understanding the origin mechanism of spontaneous or progressive (slow) events. These studies led to identifying long-term potentially unstable underground zones (hazard zones), particularly deep zones located under buildings and infrastructure. The latest are currently monitored by microseismic networks. A similar high requirement level is needed for unstable zones without taking into account the kinetics of the subsidence, which is very important for safety. Thus, GEODERIS initiated this study, primarily to acquire a better understanding of the kinetics of the progressive events group and identify the main parameters that could explain why some pillars zones developed a maximum amplitude subsidence on surface within a few hours or days, while it took several weeks to months for others. In practice, the results of this study will facilitate adapting the requirement level of microseismic monitoring system to the kinetics of pillar collapse.To retrieve the real kinetics for each event, historical and sparse documentation was used. Firstly, archives research was conducted, especially testimonies and newspaper articles published during the events. This work helped to gather useful information that sometimes contained a precise description of subsidence duration. The archives research helped to classify some progressive events according to the subsidence kinetics. Secondly, a diagnostic of geotechnical and geomechanical parameters of historic events was realized, combined with a cross analysis of the data. The analysis took into account dimensions of underground workings (e.g., pillar lengths, widths, heights, introduction of a “pillar shape factor”, and stress amount). An original expression was highlighted to connect the pillar geometry to the stress state. The kinetics expression was calibrated to classify the historic events taken into account according to the kinetics of movements. The kinetic criterion was applied to predict subsidence kinetics for the potential unstable zones currently monitored by a microseismic system."

Jan 1, 2015

By Yi-Chun Lin

Mechanical/Electrical/Piping (MEP) systems, due to their complexity and diversity, are the most intricate part of building construction. This being the case, Combined Services Drawings (CSD) and Structure, Electric and Mechanic(SEM) drawings can ensure that all coordination issues are resolved prior to construction. Construction companies attempt to apply Building Information Modeling (BIM) to manage and integrate engineering information and solutions efficiently into the CSD and SEM processes to enhance the accuracy of design and the efficiency of review. There are several powerful commercial tools, such as Bentley Navigator, Autodesk Navisworks, and Tekla BIMsight, that can review the integrated BIM model and detect conflicts in systems, and allow planners to correct the conflict issues one at a time. However, for increasing numbers of conflicts, this may be inefficient, and requires them to be arranged in a list according to impact and seriousness before solving them. For this reason, this research implements a module for conflict impact assessment based on rule-based reasoning to classify and weigh conflict impact and seriousness, and highlight the conflicted objects in the BIM system in different colors depending on their conflict type and seriousness during the analysis. This system not only detects and lists possible conflicts and errors, but also sorts them according to the severity of impact and conflict type. Planners can effectively modify the BIM models according to these conflicts as they are listed and visualized in the BIM system. If these conflicts, such as pipeline interference and problems of insufficient space, can be avoided in the early stages of planning, it facilitates the achievement of project objectives in quality, scheduling, and cost.

Aug 1, 2013

By M. B. Kime

"A set of experimental batch leaching tests studied the effect of pH, time, temperature, and stirring speed on the relative Cu, Co, Ni, and Fe leaching yields of an oxidized copper-cobalt ore sample in an aqueous hydrochloric acid solution. The results were statistically analyzed and modelled using the structural equation modelling method. Models showed that Cu, Co, and Ni leaching yields were strong functions of the leaching time and leaching temperature, whereas the Fe leaching yield depended on the leaching temperature, stirring speed, and pH. Under optimum leaching conditions yields were 99.8% Cu, 82.4% Co, 91.3% Ni, and 30.6% Fe.RÉSUMÉ Une série d’essais expérimentaux de lixiviation en bâchée ont été menés pour étudier l’effet du pH, de la durée d’attaque, de la température et de la vitesse de brassage sur les rendements relatifs de lixiviation du cuivre (Cu), du cobalt (Co), du nickel (Ni) et du fer (Fe) d’un échantillon de minerai de cuivre-cobalt oxydé dans une solution aqueuse d’acide chlorhydrique. Les résultats ont été analysés et modélisés statistiquement à l’aide de la méthode de modélisation par équation structurelle (SEM, de l’anglais structural equation modelling). Les modèles ont montré que les rendements de lixiviation du Cu, du Co et du Ni dépendaient énormément de la durée d’attaque et de la température de la lixiviation ; le rendement de lixiviation du Fe, quant à lui, dépendait de la température de la lixiviation, de la vitesse de brassage et du pH. Dans des conditions optimales de lixiviation, les rendements étaient de 99,8 % pour le Cu, de 82,4 % pour le Co, de 91,3 % pour le Ni et de 30,6 % pour le Fe."

Jan 1, 2017

By A. Mosqueda Martinez, L. C. Trytten, R. P. Kofluk, J. J. Budac

The Corefco ammonia leach nickel refinery treats Ni-Co mixed sulphides from the high-pressure acid leaching of Moa Bay nickel laterite. Due to the low iron content of the feed, the ammonia leach process generates a leach residue with ~10% Ni+Co. Since commissioning a leach residue pressure filtration circuit in 2002, this residue has been stockpiled, dried, and sold commercially. For several years, the residue was sold to nickel smelters overseas. In 2014, re-processing of the residue in the high-pressure acid leach was tested. Lab test work was completed showing excellent extraction of the contained nickel and cobalt, and additional beneficial effects in the high-pressure acid leach circuit. A plant test in Moa confirmed the results, and preparation for shipment of the valuable leach residue for re-processing has begun. This paper outlines the test work and results, and some commercial considerations.

Jan 1, 2015

By M. Kozlowski, I. Candy, S. Kashani-Nejad

The production of ferronickel and matte from nickel laterite ores is dominated by the Rotary Kiln, Electric Furnace (RKEF) process. Over time, major improvements have been made to kiln operation. In particular, kilns are now required to perform substantial amounts of reduction of the metallic oxides, thereby reducing the load on the electric furnace and substituting less expensive fossil fuel for electrical energy. To the basic refractory lined cylinder have been added: internal features such as dams and lifters, aimed at changing residence times in different sections of the kiln and enhancing gas/solids interaction, on-board fans to introduce tertiary air and on-board scoop mechanisms to allow reductant coal additions to be made at advantageous locations along the kiln. Many of these advances in design have been made on a trial and error basis and by 'borrowing' technology from related kiln processes, supplemented by proprietary modeling to various levels of sophistication. This paper presents a conceptual review of modeling components for the development of a computational model for granular material flow, combustion and heat and mass transfer in a nickel laterite kiln. These components include: granular material flow and segregation models for the simulation of bed motion, heat transfer models that simulate heat transfer by turbulent diffusion and radiation and the distribution of this thermal energy within the bed, and fluid flow models for the prediction of combustion aerodynamics.

Jan 1, 2005