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By Te Gao

It is a general expectancy that in most of the construction and renovation project, the contractor is going to hand over the as-built documents to the owner or the facility management team at the completion of the project. The main challenge for the handover process is to ensure the completeness of the captured building information and the accuracy of it in terms of how well it represents the reality. Building information models (BIMs) can be used as an information repository to store and deliver as-built information. However, due to changes made in the construction and renovation phases and errors made in the design and modeling phases, discrepancies can exist between BIMs created in the design phase (asdesigned BIMs) and actual building conditions. Laser scanning technology is able to efficiently capture accurate geometric information, which provides an opportunity to identify and quantify discrepancies and update as-designed BIMs into as-built BIMs. This paper presents a case study, within which the asdesigned BIM of a newly renovated research lab was updated into an as-built BIM using laser scanned data captured in the renovation phase. This paper introduces the challenges associated with the updating process for the as-designed BIM. In order to address these challenges, this paper introduces a framework that supports the update of an as-designed BIM by incorporating point clouds captured by the progressive laser scans.

Aug 1, 2013

By C. Diaz, S. W. Marcuson, K. I. Burgess

Deep roasting in fluid bed roasters is the first unit operation in Inco&apos;s "roast-reduction smelting" process for the treatment of nickel sulphide concentrates. The roaster product, a low sulphur calcine, is reduction smelted with coke in an electric furnace to yield a sulphur-deficient matte which is then converted to low (<1%) iron matte in Peirce-Smith converters. Due to the deep roasting, a minimal amount of sulphur dioxide is evolved in the smelting and converting stages. Sulphur is eliminated from the concentrate almost exclusively in the roasters in a single, continuous, strong, gas stream suitable for treatment in an acid plant. This paper discusses the commercial scale testing of deep fluid bed roasting of nickel concentrate at Inco&apos;s Thompson Smelter as part of two commercial scale campaigns on roast reduction smelting conducted in 1981-1982. Slurry feeding, practised during the second campaign, permitted excellent control of the air/concentrate ratio in the roaster and, in turn, good control of sulphur elimination (about 80% of input). Smooth autogenous operation with high oxygen efficiencies (about 95%) was promoted by operating at bed temperatures of830°C to 850°C with calcine recycle. High throughputs and the desired metallurgy were achieved. The extensive testwork conducted during the two experimental RRS campaigns demonstrated thot deep fluid bed roasting of nickel concentrate at high oxygen efficiency is a technically viable operation.

Jan 1, 1994

By H. Langlois

"Included in the Mines Gaspe mining complex located at Murdochville, Quebec, is a copper smelter which comprises a reverberator furnace, two Peirce-Smith converters, an anode furance, and a sulphuric acid plant.The 50% smelter capacity available is supple mentedby custom concentrates for treatment. As these concentrates can be varied and extremely complex many modifications and improvements have been brought about to optimize and make the process more flexible since its inauguration in 1955.IntroductionThe copper smelter of the Mines Gaspe mining complex is located in Murdochville, a small municipality in the heart of the Gaspe peninsula, 90 km northwest of the town of Gaspe .This metallurgical installation has a daily smelting capacity of 650 tonnes of concentrate and an output of 250 tonnes of copper and 900 tonnes of sulphuric acid. Its main components are: a reverberatory furnace, two Peirce-Smith converters, one rotary anode furnace and one acid plant. The gases, which are produced by the converters, are treated at the acid plant then combined with gases from the reverberatory furnace before being vented through a 152 metre high stack .From the beginning of its operation until the present day (1991), the smelter has treated 7 million tonnes of concentrate and 100 thousand tonnes of scrap for a production of 1.8 million tonnes of copper and 2.2 million tonnes of sulphuric acid."

Jan 1, 1993

By Yves Pépin, Sylvain Lefebvre, Dimitrios Filippou, Guillaume Hudon

"Titanium dioxide pigment plants using the so-called “chloride process” produce considerable amounts of chloride waste, which contains predominantly iron chloride. In most cases, this waste is dissolved in a weak hydrochloric acid solution and then neutralised. The metal content of the waste is dumped as hydroxide sludge, while its chloride content is lost in an effluent.Rio Tinto Iron & Titanium has developed a new proprietary process whereby pure metallic iron and chlorine gas are recovered from chloride waste by electrolysis. This process uses a two compartment cell separated by an anion exchange membrane to prevent iron cycling between its trivalent and divalent valence. The cathode is made of titanium Grade 7, while the anode is a dimensionally stable one of the type “metal–mixed metal oxide” (MMO) for the evolution of chlorine gas. The catholyte is concentrated and pH-adjusted iron-rich chloride solution originating from chloride waste. The anolyte is recirculating solution containing alkali or alkali earth chlorides such as MgCl2, NaCl, etc. Current efficiencies above 90% can be achieved at temperatures about 80°C using catholyte solutions almost saturated in iron chloride and other chlorides.In this paper, we discuss the details of this process, and how this could be integrated within a chloride pigment plant for the treatment of chloride wastes."

Jan 1, 2016

By Z. D. Hora

"There has been a number of new developments in British Columbia&apos;s industrial minerals field over the past few years. Several new industrial operations were started to diversify the line of British Columbia mineral production by magnesite, perlite and fuller&apos;s earth. Industry activities and geological projects have identified occurrences of rare earth minerals, niobium, kaoline, fireclay and zeolites. The Geological Survey Branch significantly improved its database on industrial minerals. New geological concepts based on recent work are opening a number of new opportunities f or further industrial minerals&apos; exploration and development in British Columbia.IntroductionTraditionally, the value of industrial minerals produced in British Columbia in any given year comprises between 100/0and 15% of the combined value of minerals, coal, petroleum and natural gas. Over the years a wide variety of industrial minerals has been produced , often with different levels of marketings success. For some products, such as dimension stone and clay or shale products, initial strong demand gradually dissipated; for others such as asbestos and magnesite, new discoveries or new industrial activities created demand and new markets . In some cases, such as fluorite , talc, pyrophyllite and perlite, wider use has been prevented by small size, poor quality or remote location of the deposits. Also, British Columbia , with 2.6 million inhabitant s, provides only a limited market and the industry therefore has to look beyond provincial borders."

Jan 1, 1990

By T. D. Traubert, J. T. Dietz, D. Catena

"Canadian process industry experts have often observed the strong trend for U.S. industrial safety and environmental laws to creep across the border. These experts will be interested in new United States (OSHA) regulations (29 CFR 1910.119), and anticipated new U.S. Environmental Protection Agency (EPA) regulations that will require over 28 000 U.S. refineries and chemical plants employing more than three million workers, to begin a comprehensive Process Hazard Analysis (PHA) of these complex plants immediately. Impending EPA regulations are expected to expand these efforts and add process Hazard Frequency and process Hazard Consequence reviews for many additional industrial locations.These regulations were created to reduce catastrophic industrial accidents, and emergency releases of hazardous chemicals which endanger employees, the public, and the environment.Accurate, and field verified Piping and Instrument Diagrams (P&IDs) are essential to permit a meaningful Process Hazard Analysis or emission release to be done. Today accurate P&IDs often do not exist. Many companies that have started to update their old P&IDs have found the process to be far more difficult, time-consuming,and expensive than they ever thought.This paper describes a new technique of computer drawn ""Intelligent"" P&IDs that can make a Process Hazard Analysis less expensive, more accurate, easier to perform, and provides lasting benefits to the plant owner long after the PHA has been completed."

Jan 1, 1993

"Technological innovation is an extremely complex activity. The author presents his interpretation of innovation and the innovative process. He reviews the strategy used by participants in coal mining innovation in the past and discusses changes required to meet the challenges of the future.Introduction if an industry is to be successful and viable in today&apos;s world, the companies active within the industry must remain close to the frontiers of knowledge. The coal mining industry is no exception. Technological problems facing the coal mining industry are basically economic and social. Economic problems are those concerned with the long-term growth and profitability and social problems, with the health and safety of the mine worker and the impact of the mining operation on the environment.Technological innovation can be a key factor in meeting these problems successfully. The general belief is that the information base for technological innovation exists within mining companies and governmental agencies but current industrial and governmental strategies and structures impede the transformation of this knowledge into the mining products and processes required for growth.The purpose of this paper is to determine where Canada is in terms of coal mining on the innovative ladder. The paper as presented: defines innovation and innovative process; gives an historical ""broad brush"" review o f innovation in the industry; and suggests the challenges to be faced in the future."

Jan 1, 1985

By K. B. Culver

"This paper provides background information on the expansion programs of Rio Algom Limited at Elliot Lake. Included are details on the Quirke expansion program, the Panel mine rehabilitation program, including the selection procedure for the tailings containment area, the Stanleigh mine rehabilitation program, housing, government regulations and the Environmental Assessment Board hearings. Introduction After 2Y2 years of public hearings, 4 years of arbritrating differences of opinion between our engineers and government licencing authorities, interspersed with research into radium removal and development of the LAMIX process and carrying out the work associated with some 24 control orders issued to us by the MOE, it is very difficult to compress all of the experiences and frustrations into a single paper. The highlights, as they relate to the expansion programs of Rio Algorn Limited and its affiliate, Preston Mines Limited, will be covered. Denison Mines Limited, of course, is the other uranium producer in Elliot Lake. They are currently in the process of expanding from 7,000 to 11,000 TPD by the second half of 1980 and then to 15,000 TPD by the mid 1980&apos;s. In giving this overview, the following seven items will be discussed: • The basis for Rio Algom&apos;s and Preston&apos;s expansion plans. • The Quirke Expansion. • The Panel Rehabilitation. • The Stanleigh Rehabilitation. • Housing Programs. • Government Licencing Requirements. • Environmental Assessment Board Hearings."

Jan 1, 1980

By David Dreisinger

Arsenic occurs in nature in association with many valuable metals including copper, nickel, cobalt, gold and platinum group metals. The recovery of these valuable metals is of course complicated by the need to extract and stabilize arsenic in a form suitable for disposal. In this paper, a review of some recent developments related to hydrometallurgical treatment of arsenic bearing materials is provided. The key aspects of metal dissolution, arsenic stabilization and disposal are discussed.

Jan 1, 2014

By Heather Budney

Objectives 1. Evaluate the effectiveness of ON?s EA processes using criteria from the EA and policy sciences literature. 2. Recommend improvements to the EA processes and draw lessons from the ON case for the consideration of other jurisdictions. Evaluation Process 1. Chose criteria ? 14 primary criteria (Wood 2003) ? Subcriteria from Wood (2003) and Lasswell (1971) 2. Gathered information ? 6 key informant interviews ? Published literature, policies, legislation 3. Assessed criteria and formed Recommendations

May 1, 2008

By L. Bryson, J. H. W. M. Brits, K. Voogt

"The Anglo American Platinum’s Rustenburg Base Metals Refinery (RBMR) has the world’s first full deposit nickel plating tankhouse. Impurities in the nickel electrolyte can induce stresses in the electrowon nickel deposits that could lead to delamination of the deposit. Identifying the impurities that contribute to increasing internal stresses in the nickel deposit is key to successful operation and automation of the tankhouse. Impurities were introduced in the plant electrolyte and the effects on the full-scale nickel deposits evaluated. The impurity-adjusted electrolyte solutions were also analyzed using commercially available bench-scale methods to determine the induced stress. A correlation between impurity-induced deposit stress and full-scale delamination was developed. A direct correlation can now be made between feed quality, i.e. impurity concentrations, and degree of delamination in the plant. This methodology has the potential to rapidly predict the effect of new reagents, upstream process upset conditions and synergistic interactions between impurities on deposit stress and delamination of nickel deposits.INTRODUCTION Nickel electrowinning in sulphate media was first pioneered by Outokumpu in its Harjavalta refinery in 1960 (Saarinen and Seilo, 1985). The original process was very manual with starter sheets plated onto “acid resistant” steel for 36 hours and then manually stripped and cut into sheets which could be inserted into the main production cells for a further 4–5 days. The starter sheet stripping and manufacture process was later automated. The same technology was subsequently implemented on a number of plants around the world. Anglo American Platinum’s Base Metal Refinery (BMR) began nickel electrowinning in the early 1980’s. The recent expansion of Anglo American Platinum’s Base Metals Refinery necessitated the construction of a new nickel tankhouse to achieve two primary objectives. The first to increase the capacity to 32 400 tpa nickel and the second to reduce employee occupational exposure to nickel aerosols. The new tankhouse has been commissioned and is in the process of ramp-up; more details are given by Hagemann et al. (2016). Fundamental to lowering employee exposure to aerosols was automating both harvesting and final handling of cathode. In order to accomplish this a bold move was taken to plate up to 10 days on permanent titanium blanks which are harvested by automatic crane and automatically stripped. The original development work for the plating nickel on titanium blanks over a ten day cycle is given by Bryson et al. (2006)."

Jan 1, 2017

By J. Groppo, W. Zhang, R. Honaker

"The flotation of monazite is depressed when using hydroxamic acid as a collector in the presence of calcium ions which may exist due to the dissolution of minerals such as calcite. Minor dosages of sodium hexametaphosphate (SHMP) were found to effectively depress calcite, whereas the flotation of monazite was not impaired in single mineral flotation tests. However, in a mixed mineral flotation system, monazite flotation was depressed significantly. The mechanism of hydroxamate adsorption on monazite and calcite, the depression mechanism of calcite on monazite, as well as the depression mechanism of SHMP on calcite and monazite were studied using micro-flotation, electro-kinetic, and adsorption tests. Findings indicate that the adsorption of hydroxamate on monazite was due to chemisorption while adsorption on calcite was a result of physical interaction. SHMP significantly increased the negative charges of calcite surfaces which depressed the adsorption of the hydroxamate anions on the calcite surfaces due to an elevated electrostatic repulsion force. When calcium-rich minerals such as calcite are mixed with monazite, the calcium ions dissolved from the mineral surfaces specifically adsorb onto the phosphate oxygen sites on the monazite mineral surfaces thereby causing depressing effects. The addition of SHMP to suppress collector adsorption on the calcite surfaces interacts with the calcium species that were specifically adsorbed onto the monazite surface, which prevents hydroxamic acid adsorption onto the rare earth oxygen sites due steric hindrance and results in the flotation depression of monazite. INTRODUCTIONAs one of the commercial rare earth ores, monazite has been widely exploited to produce additives for catalysts, batteries, alloys, etc. Because of the complexity and the fine nature of some monazite ores, methods such as gravity, magnetic, and electrostatic separation to treat beach sand monazite fail to produce satisfactory concentrates, suggesting the use of floatation is warranted (Cheng, Holtham, & Tran, 1993). The primary associated minerals of monazite ores include ilmenite, quartz, zircon, rutile, sillimanite (Dixit & Biswas, 1969; Pavez a& Peres, 1994, 1993). Using sodium oleate as collector for monazite has been reported in many studies (Cheng et al., 1993; Dixit & Biswas, 1969; Pavez & Peres, 1994, 1993). Several investigations have reported maximum floatability of monazite occurring at pH values between 8 and 9 (Cheng et al., 1993; Dixit & Biswas, 1969). A study conducted by Pavez and Peres (1994) compared the use of hydroxamate and sodium oleate for the treatment of a monazite ore and found that hydroxamate significantly improved the grade of rougher concentrate."

Jan 1, 2016

By C. G. McLachlan

Professor H.E.T. Haultain: To me from time to time the urge comes to say the agreeable thing as well as the disagreeable in commenting on the work of others. It is a prerogative of age. I don&apos;t apologize. To myself I justify my action as based on a long experience of the matters with which I deal, and I like to tell myself that I have a certain responsibility in such matters on account of my detached position. This Noranda article is a very fine contribution concerning Canadian milling, and I am surprised that no word of commendation or thanks has appeared concerning it in the BULLETIN. There is altogether too much written in these days by men rushing into print, concerning laboratory work, that has not been tied into, nor has resulted in application in the field. The authors of this paper have not rushed into print. The preparation of this paper was evidently an uncongenial task. If the authors had been that way inclined, it could have spread over several lengthy papers. It is an important article because it represents an enormous amount of work in the laboratory and the mill, extending over a period of sixteen years, and resulting in fine metallurgical and economic results with a very difficult and involved problem. It is a fine article because it is so well prepared and presented. It deals with an unusual ore condition, but there is much in it of use to every cyanide millman. It leaves very little room for criticism, though there may be differences of opinion in regard to some of the chemistry phases with which I am not conversant. I am struck by the enormous amount of persistent, painstaking, conscientious research work involved, and in the careful, sincere way in which the methods and difficulties have been described. Persistence and sincerity are the key note of the effort. It should have a good educational effect on the rising generation of millmen, and it should continue for long as a work of reference, and a spur to others. There has been an important by-product, the training and development of the young men engaged in the work. Three of them became superintendents of important mills. One was sought for important work in Africa, another has joined a large research organization in the United States.

Jan 1, 1946

By Abhilash

Uranium is conventionally extracted using a process that employs strong acid (H2SO4) and an oxidant (MnO2) as leaching agents. This method often creates environmental problems, requires large amounts of energy, and involves a complex operational plant. It is not, however, economically attractive to extract uranium from low-grade ores by chemical leaching. Because the content of U3O8 in the Indian ore is usually below 0.1% by weight, it is necessary to develop an alternative process to enable the efficient and economic recovery of uranium. Uranium ore from the Narwapahar mines, UCIL is a type of vein deposit found in India, which accounts for ~54% in India. The ore (0.047% U3O8), though of Singhbhum area, possess exceptionally different mineralogy due to presence of some refractory minerals and richness of apatite (5%) resulting in a maximum 78% recovery through conventional processing at UCIL, with a very high consumption of sulfuric acid and pyrolusite, besides possible loss of uranium as uranium phosphate. To avoid usage of environmentally non-benign oxidants, remediation of influence of phosphates, and improve the overall process output of uranium; an alternate extraction technology using microbial isolate(s) is worthwhile exploring and the same is presented in the paper. The microbial isolate enriched with Acidithiobacillus ferrooxidans grown from source mine water was employed for bio-leaching of uranium while varying pH, pulp density (PD), particle size, etc. On varying pH at 35oC using 20%(w/v) PD and <75µm particle size, 83.5% and 78% uranium bio-recovery were observed at 1.7 and 2.0 pH in 40 days against maximum recovery of 46% and 41% metal in control experiments respectively. Whereas, it was observed that grinding of ore to finer size actually helped dissolution of uranium. Finer size particles (<45µm) gave a maximum biorecovery of 93% in 40days at 10%(w/v) PD, 1.7 pH and 35oC. The bio-recovery of uranium fell down from 93% to 82.73% and 60% on increasing the pulp density from 10% to 20% and 30% respectively for particles of <45µm size. The higher uranium dissolution during bioleaching at 1.7pH can be correlated with increase in redox potential from 433 mV to 664mV in 40 days.

Aug 1, 2010

By Chunlin Chen

Published data on thermodynamics of tin in liquid copper, matte and slag have been reviewed, assessed and used in development of thermodynamic solution models of melts. The developed model/database was applied in modelling the Sn deportment in primary copper smelting and e-waste melting processes. The results show that Sn can be removed from the matte through evaporation of various volatile Sn species (with SnS the most volatile) and slagging during copper smelting. The Sn removal increased with increasing matte grade due to the increased gas and slag volume. In the e-waste smelting process, fluxing strategy was developed for smelting e waste to produce a slag with reasonable liquidus and viscosity. Modelling results show that very low amounts of Sn reported to the gas phase due to low S, hence low SnS partial pressure in the system. The black copper produced could contain a few percent of Sn depending on the oxygen potential. The Sn in the black copper could be removed to the slag phase during anode refining. INTRODUCTION Tin is an impurity element commonly found in copper ores, which will be dispersed into various solid, liquid, and gaseous streams during the pyrometallurgical processing of copper. Tin alloy is widely used in electronic soldering due to its low melting point. The growth in treatment of recycled e-waste through primary and secondary copper smelting has led to an increased tin input to the smelting system. Therefore, the deportment of tin between phases is of great interest to the operators of modern smelters. Multi-Phase Equilibrium (MPE) is a thermodynamic package developed by CSIRO for simulating reactions between phases in multi-component and multi-phase systems (Zhang et al., 2002). Over the years the capability of the MPE model has been extended to cover the behavior of a large number of elements in high temperature system (Chen, Zhang, Wright, & Jahanshahi, 2006). In the present paper, the thermodynamic data on tin in liquid copper, matte and slag have been reviewed, assessed and used in the development of a database for Sn slag, alloy and matte phases. The model/database was applied in modelling the tin deportment in primary copper smelting and e-waste smelting processes. The aim of this study is to provide a better understanding of the chemical behaviours of tin in high-temperature copper processing and e-waste smelting.

Jan 1, 2019

By R. P. Viljoen, A. L. Sokolov

"The distribution of mineralized provinces is analyzed on the basis of their genetic link with specific blocks of the earth&apos;s crust including ancient platforms, mobile belts and zones of tectonicmagmatic activation. Mobile and fold belts surround the Siberian platform in Russia and the Kaapvaal craton in South Africa, with decreasing age zoning away from ancient platform margins. The main differences in the geological development of the two cratonic areas are: (1) the long period before the final stabilization of the Siberian platform (3600 Ma to 1600 Ma) and the comparatively short period of time for the stabilization of the Kaapvaal craton (3600 Ma to 3050 Ma) and (2) the intensive multiple activation of the marginal zones of the Siberian platform and the tectonicallycontrolled, magmatic sedimentary, intracratonic activity, typical of the Kaapvaal craton. Mineralization of the Siberian platform is largely characterized by marginal reactivation zones of differing ages although mineralized intracratonic Cu-bearing basins of Proterozoic age are also known. Mineralization of the Kaapvaal craton is mainly related to the formation of the intracratonic basins i.e., Witwatersrand (Au, U) and Transvaal (Au). The latter is characterized by multi-age volcanic-intrusive activity including the emplacement of Bushveld Complex (Cu, Ni, Pt, Cr, Au, V). The Siberian platform is characterized by the prolonged development of inherited mineralization from Archean until the late Mesozoic. The main period of mineralization in the Kaapvaal craton is restricted to the middle Proterozoic.The Baykal-Patomskaya and Namaqua-Natal mobile zones occupy similar positions adjacent to the Siberian and Kaapvaal cratons, respectively, and demonstrate similar modes of metallogenic development: i.e., the early formation of exhalative Pb-Zn-Cu deposits during the early stage and magmatic Cu deposits during the late stage. The more remote mobile belt near the Siberian platform, the Trans-Baykal, is characterized by intensive multi-age mineralization (Wo, Mo, Sn, fluorite), related to a period of tectonic-magmatic activation. The Saldania Belt occupies a similar position near the Kaapvaal craton but is known for its poor Au, and Cu mineralization. It does, however, have some similarities with Trans-Baykal Belt in regard to Mo-W bearing granitoids.The phenomenon of interference of geosynclinal, orogenic, platform, and tectono-magmatic activation regimes is known for the Russian section of the Pacific Ocean Volcanic Belt."

Jan 1, 1994

By M. Sommerfeld, U. Schwarz-Schampera, B. Friedrich, D. Friedmann

The steadily growing demand for metals and their price increase at metal exchanges make the mining and utilization of marine mineral resources like polymetallic nodules, manganese crusts or sulfide deposits in the near future a viable option to potentially increase the supply of base and precious metals. For a country with low potential to mine land-based resources like Germany, the industrial recovery of metals from marine mineral resources could lead to a decreased dependency on imports. In this study, seafloor massive sulfides from the German license area in the Indian Ocean (Kairei field, Southern Central Indian Ridge) are treated to recover copper and precious metals. The aim of the project is to demonstrate the transferability of existing metallurgical techniques to the raw material of deep-sea massive sulfides. As a starting point to process this unconventional resource, samples from the Indian Ocean are chemically analyzed and mineralogical characterized. A comparison is carried out between the samples and land-based copper resources, to highlight the potential which lies in mining the deep-sea floor. This paper will show the general possibility of applying a two-stage pyrometallurgical process, based on a concentrate smelting operation, followed by a converting operation in lab-scale to the provided samples of massive sulfides. Generated slag from the concentrate smelting and the converting operation are investigated by X-ray diffraction to determine the mineralogical composition. The two-stage pyrometallurgical process is investigated by the thermochemical modelling tool FactSageTM 7.2 to evaluate the phase distribution of relevant elements between the metal, matte, slag and gas phase. The thermochemical boundaries of the pyrometallurgical process are therefore set and the results of the thermochemical study can be used as an indicator for the efficiency of an up-scaled process and the generated amount of side-streams, which need to be further treated or circulated back into the process. INTRODUCTION Seafloor massive sulfides (SMS) are the third kind of discovered deep-sea minerals besides ferromanganese nodules and cobalt-rich ferromanganese crusts (Sharma, 2017). They occur in water depths around 250–4,000 m (Koschinsky et al., 2018). SMS are characterized by a high base metal and sulfide content. They were created by fluid circulation and hydrothermal convection over time (Han et al., 2018). Commonly, areas rich in SMS are associated with hydrothermal vent fields on the seafloor (Keith et al., 2018).

Jan 1, 2019

By N. Moelans, I. Bellemans, K. Verbeken

In this work, we present a phase field model to simulate the facetted crystallization of Fe3O4 in a quaternary FeO-Fe2O3-Cu2O-SiO2 melt under different partial pressures of oxygen. An important focus in creating more realistic phase field models is the incorporation of the thermodynamic driving forces in multicomponent multiphase-field models by coupling to thermodynamic databases. The diffusion of FeO, Fe2O3 and Cu2O is considered. The ratio of FeO/Fe2O3 at the upper boundary is in equilibrium with the oxygen fugacity of the atmosphere, while conserving Fe. Two-dimensional simulations are performed with different varying oxygen fugacity in the atmosphere. For the considered composition range, the growth velocities of the spinel crystals increase with decreasing oxygen fugacity. INTRODUCTION Crystallization of silicate melts has its applications in geology, pyrometallurgy and glass making. In pyrometallurgy, the solidification of slags influences the freeze lining behaviour (Campforts et al., 2007) and the cooling of slag after tapping (Durinck, Jones, Blanpain, & Wollants, 2008). Modeling of silicate melt crystallization is frequently done on the macroscopic level, using thermodynamic equilibrium calculations to determine the fractions of all phases as a function of temperature. The Factsage software and database package (Bale et al., 2016, 2009, 2002) already proved its usefulness in pyrometallurgical applications, for example to model the phase mixture after solidification of a stainless steel slag (Durinck et al., 2008). Crystallization of phases typically results in complex morphologies on the mesoscale, e.g. dendrites or facetted growth. On this mesoscale, the phase field concept has proved to be a very powerful tool (Moelans, Blanpain, & Wollants, 2008) for modeling crystallizing microstructures, because it can treat arbitrarily complex interface shapes with minimal mathematical complexity. In contrast to macroscopic models, the diffusion profiles and crystallization kinetics can be described as well as the morphology of individual crystals. First, Kobayashi (Kobayashi, 1993) simulated a growing dendrite in a pure undercooled metallic liquid. Then, Warren and Boettinger (1995) simulated a dendrite in an isothermal system considering a binary alloy. The extension to multi-phase systems was done by Steinbach et al. (1996). This was further extended by Tiaden, Nestler, Diepers, and Steinbach (1998) to a framework with coupled diffusion and phase field equations in multi-component systems.

Jan 1, 2019

By Esa Peuraniemi, Hanna-Leena Heikkilä

Boliden Harjavalta has been operating a copper flash smelter since 1949. Thus, in 2019, the smelter is celebrating its 70th anniversary of flash smelting. Slag formation is an integral part of the smelting process; currently the processing of slag is based on froth flotation at the slag concentrator. It provides high recovery of copper but restricts slag utilization; the final copper slag is deposited in a landfill. The Harjavalta smelter commissioned a new landfill area for final slag in May 2018. This paper describes the full project from permitting to commissioning of a new landfill area. The permitting process is described comprehensively, including environmental impact assessment together with the environmental and dam safety monitoring. During the environmental impact assessment, observations on rare animals protected on European level were made as well as archaeological findings. Successful completion of the permitting allowed the construction phase to start on time. After six years of intensive work, the new landfill was commissioned in May 2018. The new landfill area provides a sustainable way to store the smelter’s slag for decades to come. INTRODUCTION Slag processing Sulphide based concentrates have always formed the main raw material stream at Harjavalta’s copper smelter. During the smelting and converting steps, the iron included in the concentrate is oxidized and fluxed using a silica-based sand. Originally, the slag was processed by using an electric slag cleaning furnace after which the final slag was water granulated. Froth flotation has been utilized for slag treatment since 1966. In the beginning, the slag was cooled in open ditches. In 1984, controlled slow cooling of slag was licenced to enhance copper recovery at the flotation plant. Today, the slag from both the smelting and converting is tapped/skimmed to slag ladles and treated in the following steps: Slag ladle transportation from the smelter to the cooling area by slag hauler Slow cooling of slag in the ladle to allow mineral precipitation Unloading the slag by tilting the ladle; causing the slag to crush as it drops from the ladle Feeding the crushed slag (-500 mm) by wheel loader to a slag concentrator’s feed funnel followed by a conveyor belt transporting the slag to the concentrator plant Crushing and grinding using lump and pebble mills Froth flotation of the valuables Recycling the slag concentrate back to the smelter feed after dewatering Pumping the final copper slag to the landfill area.

Jan 1, 2019

By L. Beiza, L. Velásquez-Yévenes

Chalcopyrite is by far the most abundant copper sulphide on Earth, but it has proved to be problematic in its processing by leaching, mainly related to its refractory nature, slow kinetic rates of dissolution and the formation of an inhibiting product layer on its surface during leaching. This study is focussed on the electrochemistry of chalcopyrite dissolution in acidic chloride system, which has recently gained attention as a feasible alternative to conventional sulphate media for chalcopyrite leaching. It is well understood that chalcopyrite dissolution from mineral grains depends strongly on the solution redox potential at the mineral surface as well as the composition of the product layer that may form on its surface. The chloride ions in solution support the Cu(II)/Cu(I) couple as the primary oxidant, as they can form complexes with the cuprous ions formed, increasing the dissolution rate. Additionally, these ions increase the potential range where chalcopyrite can be oxidized. The chemical reaction that occurs on the surface of chalcopyrite in chloride solutions in the presence of cupric ions will be characterized and the coulometry of the reaction will be reported to understand what is happening on the surface of chalcopyrite. Electrochemical experiments have been carried out to investigate the behaviour of mixed potential by open circuit potential (OCP) measurement for 30 minutes using sulphuric acid at pH 1 under nitrogen at 25⁰ C. The effect of chloride was analysed at 0, 20, 50 and 100 g/L and cupric ions from 0 to 50 g/L. The potentials obtained were then used to carry out chronoamperometry tests for a period of 30 minutes in absence of cupric ions. The mixed potential did not show a significant difference with an increase in cupric concentrations in the absence of chloride. Increased mixed potentials and current densities were observed at higher chloride and cupric concentrations. Chronoamperometry tests at those potentials were used to construct a voltammogram trace which has the same trend as a normal cyclic voltammogram but with much lower current densities. INTRODUCTION As a result of the depletion of copper oxides, the leaching of copper sulphide minerals has become the focus of many studies. Chalcopyrite, (CuFeS2) which is the most abundant of copper minerals, has proved to be challenging to process via hydrometallurgy, mainly related to its refractory nature, slow kinetic rates of dissolution and the formation of an inhibiting product layer on its surface, during leaching.

Jan 1, 2019