Search Documents

By Professor of Civil and Environmental Engineering Northwestern University, Mike Wladron, Gordon Revey

A unique judicial opportunity allowed measurement of the response of three cracks in residential structure to blasting for underground aggregate mining. Instrumented cracks were located in the interior basement CMU mortar and upstairs dry wall as well as exterior brickwork. The dynamic environment was unusual. Even though the blasting occurred some 490 m (1600 ft) away, excitation frequencies were unusually high and there were no apparent surface waves. In addition there was no air overpressure wave to produce secondary crack response. As is typical, long term environmental effects produced greater crack response than did the blast induced ground motions.

Jan 1, 2007

Geochemical projects in progress or recently completed in the Bureau of Mineral Resources, Geology, and Geophysics (BMR) cover a wide range of topics and include research projects, regional studies, and prospecting programmes. However, in these notes emphasis is given to projects which are directly relevant to mineral exploration.FIELD INVESTIGATIONSStream sediment sampling, rock and soil sampling, and geobotanical surveys have been used by the BMR in a number of areas, partly in attempts to locate specific zones of mineralization, and partly to investigate the effectiveness of the various methods under different conditions of climate and topopraphy and in different geological settings.Stream sediment sampling has been most successful in the Territory of Papua and New Guinea. For example, in the South Sepik area, zones of disseminated su1phide mineralisation were found to give rise to anomalies with peak values of up to 1,000 p.p.m. copper, compared with background values of about 40 p.p.m. (Dow et al., 1968). By contrast, the results of rather limited work in the Northern Territory and in the Kimberley district of Westen Australia were inconclusive.Rock and soil sampling, on the other hand, was successfully used in a number of areas in Northern Australia, particularly at Rum Jungle and Tennant Creek.Rum Jungle area In the Rum Jungle area, where uranium and base metal mineralization is mainly associated with a Lower Proterozoic black slate sequence, samples, of c-horizon soil or weathered 'rock are generally collectedfrom the bottom of drill holes, usually 15 to 20 ft deep, bored with a power-operated auger.Surface sampling indicates that such a technique would probably have shown up all the major geochemical anomalies delineated by deep sampling, but the latter gives slightly more consistent and slightly

Jan 1, 1970

By Ingrid Hann

The Triple Bottom Line ? Economic Sustainability ? Creation of Joint Venture companies ? Planned evaluation of other kimberlites ? Social Sustainability ? Impact Benefit Agreement and Participation Agreements ? Education and training initiatives ? Environmental Sustainability ? Environmental management ? Mine closure planning

May 1, 2008

By A. McLean, M. Iwase, K. Wakimoto, K. Katogi, Y. Kikuchi

One of the greatest obstacles to the application of physical chemistry principles to the elucidation of slag-metal reactions is a lack of knowledge of activities of the reacting species. To a large extent, oxygen potential of the slag phase governs iron and steelmaking practice. Without oxygen control by means of appropriate sensors, the behaviour of the other elements cannot be managed. In this paper, measurements of the FeO activity with various types of electrochemical FeO sensors will be described together with examples of their applications for improved strategies toward better practice for ladle metallurgy and sulphur and manganese distributions between slag and metal phases during steelmaking. Measurements of FeO activity have also been made in order to improve dephosphorization reactions. This type of work has led to significant reduction in volume of slag generated within the steelmaking vessel, which in turn has important implications for refractory wear, metal yield, alloy recovery and improved productivity. Finally, an on-line sensor is described that permits the oxygen potential to be determined for both the metal phase and the slag phase during steelmaking in the BOF.

Jan 1, 2004

By J. A. McLennan

Nickel laterite deposits are typically formed from tropically weathered mafic-ultramafic complexes. The resulting nickel concentration is found within soil horizons and is mineable with regular dozer units. At the time of mining, digging elevations are needed at selective mining units (SMUs). Moreover, for mine planning, the costs due to dilution and lost ore require mining elevations to be specified. A conditional simulation approach is used to calculate ?optimum? SMU mining elevations. Multiple realizations of the ore base surface are simulated. For a single bottom surface realization, dilution and lost ore costs are calculated over the entire vertical extent of each SMU. The optimum mining elevation is the elevation where the lowest summed cost of ?accepting dilution? and ?wasting ore? occurs. The reported SMU dilution is the cost of mining the volume of waste located below the bottom surface and above the optimum mining elevation and the reported SMU lost ore is the cost of not mining the volume of ore above the bottom surface and below the optimum mining elevation. For all ore bottom surface realizations, optimum SMU mining elevations and their associated dilution and lost ore costs are calculated and compiled to represent production uncertainty.

Apr 1, 2005

Exerting the Advantages of National Key Discipline, Outstanding the Training of Engineering Capability, Cultivating Talent to be with Innovation Ability

Sep 13, 2010

By Tim O’Neil

Dressed in black tie and Victorian attire, some 200 people came to Leadville, CO, for a September weekend featuring a National Mining Hall of Fame and Museum (NMHF&M) induction banquet and a scenic mountain train trip to Fremont Pass and the Climax Mine. The 18th annual induction banquet on Sept. 17 began with cocktails and a open house. It was a chance for visitors to tour the National Mining Museum including the new Hennebach Wing, opened in February. The new wing is named in honor of Ralph Hennebach, retired chairman of Asarco. Formerly Leadville Junior High School, the Hennebach Wing encompasses more than1,440 m2 (15,500 sq ft) of floor space in two stories. One prominent feature is a 1923 Wills Sainte Claire touring sedan. Climax Molybdenum donated this first all-molybdenum steel motorcar. Docents were available throughout the museum to give banquet attendees directions and answer questions.

Jan 1, 2005

By Antonio Rivera

On Nov. 13, 1985, Colombia's Ruiz volcano erupted, killing an estimated 25,000 people and burying several villages. Damages were estimated to be about $US300 million. The following is an account by SME member Antonio Rivera of the volcanic activity that led to the eruption. His account also includes a description of the geography and some geology of the affected area. Mining operations in the area were mostly unaffected, although some operations were forced to close until the roads leading to them could be repaired. Introduction The Ruiz volcano is located on the Central Cordillera of Colombia about 28 km (17 miles) southeast of Manizales, the capital of the state of Caldas. Ruiz is one of nine volcanoes that form a complex volcanic chain within the middle portion of the Central Cordillera. The Cordillera has 30 other volcanoes in the southern part of Colombia. Ruiz volcano Ruiz's elevation is 5200 m (17,060 ft). It is covered by an ice cap estimated to be 20 m (66 ft) thick at its summit, an area that covers 17 km2 (6.5 sq miles). Drainage is composed of several rivers that flow into the Magdalena River on the east and Cauca River on the west. The rivers flowing to the east are Guali, Azufrado, Lagunillas, and Recio. The rivers that flow to the west are Claro, Molinos, and Chinchina. There is a road from Manizales to El Refugio, a ski area located on the northeast flank of the volcano at 4800 m (15,750 ft) in elevation. The Ruiz volcanic complex was built in two stages. The first is a shield type of volcano (mainly lavas) formed about a million years ago. The second is a younger stratovolcano overlaying the ancient one. It consists of lavas and pyroclastics and was built over the past 500,000 years. Twenty-four eruptions of Ruiz are known to have occurred during the last 14,000 years. Its products mainly consist of lava flows, pyroclastic flows, mudflows (lahars), and directed lateral explosions. Historic eruptive record 1595 - Debris avalanche, blast, pyroclastic flows, mudflows, ash flows, and ash fall. 1828-1829 - Ashes (phreatic). 1831-1833 - Gas emissions and ashes. 1845 - Mudflows and pyroclastic flows. 1985 - Sept. 11- Fumarolic activity, phreatic eruption, ash fall, and small mudflows. 1985 - Nov. 13 - Ash and pyroclastic fall, major destructive mudflows (magmato-phreatic eruption). From 1845 through 1984, Ruiz volcano always had a slight fumarolic activity. It was restricted to the crater area. In November and December 1984, the fumarolic activity increased and the first ash emission and vapor-sulfur formation started. Small local earthquakes accompanied these volcanic activities. The volcano had a small erup¬tion on Sept. 11, 1985. It was manifested by phreatic explosions that ejected fragments of the vent and formed ash deposits 25 mm (1 in.) thick around an area 2.5 km (1.5 miles) from the crater. Fine material was blown by the wind and reached Manizales and neighboring areas, producing a small layer of ash up to 10 mm (0.4 in.) thick.

Jan 2, 1986

By D. E. Calisaya, É. Poulin, A. Desbiens, R. del Villar, A. Riquelme

"A 15 cm diameter by 732 cm height, fully automated pilot column was installed in the Agnico-Eagle’s Laronde concentrator (Québec), for evaluating the performance of newly developed sensors and advanced process control algorithms. For eventual comparison purposes, the pilot column is continuously fed with the same slurry feeding the copper-circuit third cleaner column. It is equipped with electrical conductivity-based sensors for estimating the three variables used in the multi-variable control algorithm under evaluation: froth depth, fraction of wash water underneath the interface and gas hold-up. Froth depth is regulated using a PI controller while a predictive controller is formulated as the minimization of the tracking errors of gas hold-up and bias rate, keeping several operating constraints between their practical upper and lower limits. In particular, an unreachable high set point of gas hold-up can be selected in order to maximize the bubble surface area available for particle collection, while maintaining bias rate above a minimum value required for froth cleaning. The proposed strategy may indirectly help optimizing flotation column operation by using these secondary variables, without the implementation of a real-time optimization layer.INTRODUCTION Flotation columns have already been used for more than 30 years, mainly in cleaning stages, as a result of their froth washing capabilities. Despite their widespread usage, the measurement of some pertaining variables and their use for automatic control is rather scarce. Among the most important variables directly related to the process metallurgy (concentrate grade and recovery), froth depth (hf) is the only one normally monitored and controlled. Even though commercial sensors are available, gas hold-up (eg), a variable directly related to concentrate recovery, is seldom measured and never controlled. Another important variable, bias rate (Jb) responsible for concentrate cleaning, is simply not measured at all, as there is no commercial sensor available. Therefore, besides froth depth, continuous monitoring of process variables is limited to flow rates (gas, feed, tailings, wash water), i.e. to manipulated variables. Some new available sensors have been industrially tested, e.g. the Sonar-TracTM for eg (O'Keefe, Viega & Fernald, 2007) and the McGill hold-up sensor (Tavera & Escudero, 2002). Others, for bias rate and frother concentration, have been successfully validated at laboratory scale by Laval’s LOOP researchers (Maldonado, Desbiens, del Villar & Chirinos, 2008b; Maldonado, Desbiens, del Villar & Aguilera, 2010a). Some devices have been extensively used for monitoring bubble size and space distri-bution, e.g. McGill bubble viewer (Gomez & Finch, 2007) and others."

Jan 1, 2012

By S. J. Haynes

"This paper documents the characteristics of the different quartz veins, and their relation to gold, in the turbiditic Meguma domain of eastern Nova Scotia. Eleven different types have been distinguished in the greenschist facies on the basis of form, internal structure, mineralogy, wallrock alteration and crosscutting relationships to each other and to regional structures. Gold is present as rare visible disseminations in host rock slates and in ore-grade, early-formed veins, that pre-date the formation of upright Acadian folds and intrusions of Devonian granitoids. Four vein types pre-date Acadian folding. Five gold-deficient vein types are associated with Acadian folding (syndeformation); whereas two gold-deficient vein types clearly post-date this deformational event: Previously unreported, wall rock alteration is associated with early crosscutting and semiconcordant auriferous veins. In contrast, early stratiform veins are devoid of wallrock alteration. It is suggested that the auriferous vein arrays formed as submarine exhalitive systems over synsedimentary tensional faults and that the Meguma domain may represent the opening of a basin similar to the modernGuaymas rift .IntroductionThe term ""turbidite-hosted gold deposits"" is introduced to distinguish gold deposits contained within a turbiditic sequence of wackes and shales (or their metamorphosed equivalents) from gold deposits in other types of sediments. Usage and justification for the term is similar to ""carbonate-hosted lead-zinc deposits"" or ""volcanogenic massive sulphides"". A range of different characteristics can be present in individual deposits, some of which may be indicative of specific deposit types in the same manner that volcanogenic massive sulphides can be subdivided into ""Cyprus type"", ""Kuroko type"", ""Besshi type"", etc. Historically, gold deposits hosted by turbiditic flysch were an important class of quartz-vein gold mines in the 19th century. They included the goldfields of Victoria, Australia, Otago, New Zealand and Nova Scotia, Canada. Production from most of these fields had ceased by World War II and interest in this type of deposit waned. However, the recent exploration interest in gold has resulted in both re-assessment of the classical mining camps and the discovery that ""turbidite-hosted"" gold deposits are present in many parts of the world.Mapping of the regional geology and gold deposits of the Megumadomain of Nova Scotia was carried out by E.R. Faribault of the Geological Survey of Canada between 1886 and 1939. Faribault produced a comprehensive series of maps and reports for each gold district, a compendium of which was published by Malcolm (1929)."

Jan 1, 1987

By C. C. Anderson

"While conducting investigations in connection with the helium program of the Bureau of Mines, the Cryogenic Laboratory has improved an apparatus for the rapid and accurate determination of the helium content of natural gas and gaseous mixtures derived from that source. The separation of helium is effected by the use of activated coconut charcoal which, when cooled to liquid-air temperatures, absorbs the nitrogen and other constituents of the gas, leaving the helium in a. spectroscopically pure state. This absorptive property of activated charcoal was discovered- by Dewar3/ in 1875. Several years later, while conducting their original researches on helium in natural gas, Cady and McFarland employed the charcoal method for the absorption and removal of the common constituents of natural gas and constructed an efficient apparatus in which this operation could be effected.4/ Shortly after initiating the government's helium activities during the World War period, the Bureau of Mines adopted, with Minor modifications, the Cady and McFarland apparatus and method of analysis. Seibel.5./ described this modified apparatus and method of procedure as part of a publication on helium-bearing natural gas. Subsequently, the Bureau's apparatus for helium analysis has been simplified and improved to facilitate more rapid and positive operation. The apparatus and method of procedure now being used by the Bureau of Mines Cryogenic Laboratory arc described in this paper.The personnel of the Bureau of Mines Cryogenic Laboratory has improved and brought the helium apparatus described herein to its present state of perfection. The writer's contributions have been-of minor importance, and he wishes to give the various members and former members of the laboratory staff full credit for the improvements they have made. He also desires to express his appreciation for suggestions and criticisms offered during the preparation of this paper to the following members of the Petroleum and Natural Gas Division, Bureau of Mines, which now includes the Amarillo Helium Plant and Cryogenic Laboratory: H. A. Cattell, chief engineer; C. W. Seibel, supervising engineer of the Amarillo Helium Plant; W. M. Deaton, chemist-in-charge of the Cryogenic Laboratory; and H. S. Kennedy.The quantitative determination of helium in a gaseous mixture is accomplished by the removal of the other constituents from the sample, either by chemical or physical Means, leaving only the helium which can be measured directly. Chemical methods, when applied to natural gas, require the burning of the hydrocarbons in oxygen, the, absorption of the resulting carbon dioxide in a caustic solution, the removal of the excess oxygen in a suitable solution such as an alkaline pyrogallate, and the elimination of nitrogen by sparking or by combination with hot calcium or magnesium.. Such procedures are very slow and tedious compared with the physical method which employs the absorptive property of activated charcoal to effect the separation of the other constituents from the helium."

Jun 1, 1934

By P. Ulrich, V. Svalbonas

The early to mid 1980s was a period of mining consolidation, and many senior design engineers retired from the mill industry. Similar conditions have existed in the last few years. This creates a loss of a tremendous amount of experience. This paper is a look back by two senior mill designers who survived the dips in both time periods. From a continuous design practice of over 25 years, mill designs and fabrication practices are surveyed with a view of identifying what works, and is necessary, and what doesn’t, or is not necessary, in the creation of a safe, economic, long-lived grinding mill.

Jan 1, 2001

By Wade Edward Speer

The Hiddenite District of Alexander County, NC has produced some of the world?s finest large emeralds since the first one was discovered 134 years ago. In fact, North America?s largest emeralds come from the district, making this one of the continent?s most unique gem deposits. In addition to emeralds, the Hiddenite District is also famous as the discovery site for the rare spodumene mineral hiddenite, first identified in 1881. Nowhere else in the world do these two minerals naturally occur together. The emeralds are a unique color variety of beryl (Al2Be3Si6O18) with trace amounts of Cr+3 and V+3 substituting for Al+3. The hiddenite (LiAlSi2O6) crystals also exhibit emerald green color due to traces of chromium. Consisting of three large deposits and numerous prospects, the district encompasses an area of 10 km2 (4 sq miles) centered on the small town of Hiddenite. Operations at the Adams, Ellis and North American Emerald Mines properties have been productive at irregular intervals since the 1880s. Currently, only the North American Emerald Mines property is being mined on a regular basis. Recent activity there has exposed a 3-hm2 (7.4-acre) pit with depths of 25 m (82 ft) that provides the best exposures of unweathered bedrock seen in the district in more than 120 years. Although no official records exist, public and private data indicate that the production of the entire Hiddenite District from 1880 to 2007 is about 70,000 carats of emerald and 20,000 carats of hiddenite. The bulk of the emeralds came from the North American Emerald Mine property (NAEM, formerly known as the Rist Mine) where sustained mining replaced the previous sporadic prospecting in 2000.

Jan 1, 2009

FREQUENTLY the Survey Department is caIled upon to estimate the quantity of material in various dumps, dams piles, etc... and in the carrying out of this work various methods may be employed.The method used will vary according to the particular case in hand, and factors such as accessibility of the top of the dump, steepness of its sides, height, and the condition of the material to be estimated. A certain amount of "give and take" must be adopted in the treatment of small local cavities and mounds.In all cases it is desirable that the surveys made should be tied on to the lease surveys for the purpose of location, and that all levels should be reduced to the mine datum. It is also desirable to obtain levels of the original surface before deposition of the material to be estimated. If these have not been obtained beforehand, levels and transfers round the top will be the next best. If space is availabIe, flat surface is chosen as a site for the dump, etc. This is of the utmost importance in those cases where the material will have to be...

Jan 1, 1925

The stratigraphy of the Western Coalfield is briefly reviewed and the important units of the Lithgow Coal Measures, particularly the coal seams, are defined. The possibility of coal measures of Tomago age ocurring near the edges of the Sydney Basin is discussed onpresent evidence.Using data obtained from unpublished drilling records, detailed structural, isopachous and lithofaeies maps have been drawn. These show that the structure of the coal basin has been influenced by the underlying basement in many ways.The prominent jointing in the overlying Triassic sandstones is discussed in relation to jointing in the coal measure sediments.It is concluded that in addition to the general knowledge obtained with respect to the coal basin, useful information regarding coal quality and quantity can be gained by the study of broader sedimentary and structural features.INTRODUCTIONThe term "Western Coalfield" covers approximately the area from Katoomba to Rylstone, together with the smaller, separate Ulan area (Fig. 1). The area studied is part of the great sedimentary Sydney basin named by Osborne (1948). The first discovery of coal in Sitlt in the area was made in 1824 by Andrew Brown, although George Bass noted the presence of coal float in the Grose River in 1797. Production is recorded from the Western Coalfield in 1838 but mining was intermittent until 1868 when mines in the Lithgowvalley (producing coal from the Lithgow Seam) came into production. In 1882 the Katoomba Seam was first worked at Katoomba.The work of J. E. Carne (1903, 1908) defined the limits of the Coal Measure sediments and also contributed a great amount of valuable detailed information about the region.

Jan 1, 1960

By Mike Cammack, Logan Huppert, Gustavo Azpilcueta

During the summer of 2015, Unisea Inc. sought proposals for the G1 Dock Replacement Project in Dutch Harbor, Alaska. It would be a one year project and construction was scheduled to begin in the spring of 2016. One aspect of the project was the requirement for a layer of armor stone to protect part of the dock. An estimated 30,500 tonnes (37,670 t) of armor stone were needed for the project. The source of rock was the Unisea Quarry due to its proximity to the project and the quality of the stone meeting all the required technical standards.

Jan 1, 2018

By A. Tylczak, C. Norman, C. Shook, S. Loif

"There are a lot of good reasons to manage energy use at mining operations. Optimizing process energy use reduces operating costs. Tracking energy use can help identify unplanned process changes or malfunctioning equipment early, which allows problems to be corrected promptly.Sacré-Davey Engineering in Vancouver has performed over 50 Energy Management studies for various industries including: mining, pulp and paper, oil and gas, etc. Energy Management programs can be used to identify energy reduction opportunities, assess project feasibility, complete equipment selection trade-offs, as well as to monitor and manage energy costs. Benefits of energy management programs are reduced energy costs, reduced maintenance, and increased plant automation. Additionally, energy management can provide access to utility incentive funding and quantify savings which can greatly improve the return on investment of potential projects.Energy management studies are funded by many Utility programs across Canada. There are various programs available for existing plants energy audits, project feasibility studies, new plant design reviews and energy monitoring and targeting, etc. There are capital incentives available which can significantly reduce payback period.This paper discusses how energy management can be used to support mill/mine operations groups, maintenance programs, as well as expansion or green field projects. This paper will also provide an overview of Canadian Utility companies programs and how they can assist mining companies.IntroductionThere are a lot of good reasons to manage energy use at mining operations. Optimizing process energy use reduces operating costs. Tracking energy use can help identify unplanned process changes and identify malfunctioning equipment early, which allows problems to be corrected promptly."

Jan 1, 2015

By C. Kruger

Anglo American Platinum has adopted a strategy of best practice principles (BPP) for sampling, mass measurement, analysis, and metal accounting for more than a decade now. When new plants are designed, the most suitable sampling equipment and sampling protocols are implemented and material flows and plant layouts are designed around sampling strategies. A few years ago, a crushing plant for a high-grade matte stream was commissioned. The design called for the high-grade material to be crushed to 95% passing 2 mm, and the design allowed for a single-cutter primary Vezin sampler taking increments from a gravity flowing stream at regular intervals while filling a tanker for pneumatic offload at the base metal refinery. This was a single point of sampling and analysis that would measure the wanted output from the smelting complex and the input to the refineries. In addition, the design incorporated the functionality to collect increments in an ?interleaved? fashion from the Vezin sampler for internal precision checks. The metal accounting strategy for Anglo Platinum involves the ongoing measurement of all inputs, outputs, and stock levels for all operations for platinum group metal (PGM) and base metal (BM) content. Included are yearly stocktakes, usually done on 1 February, across the smelters and refineries (at least the base metal refinery). In the accounting period immediately following the introduction of the new crushing and sampling facility, a trend was developing whereby the absolute difference between the physical stock and theoretical stock (PGMs predominantly) increased for the two respective sites on an ongoing basis. The smelter showed an increase in physical stock compared to the theoretical stock (sender) and the base metal refinery showed an increase in theoretical stock against physical stock. Because of this anomaly, an additional stocktake was held in September for the period in question, and it was confirmed through the physical stock measurement results that the PGM accounting problem was indeed pointing towards the evaluation of the high-grade matte stream. This paper showcases parts of the process that took place to explain the poor accountabilities for the two sites. Previous results from the sampler ratification process (of the interleaved sampling design) were reanalysed, a physical inspection was carried out on the sampling system again, and the sampler performance was monitored (quality control parameters) for the period. From these investigations, it was found that airflows inside the Vezin introduced the sampling bias. A change in sampling protocol was introduced, as well as certain physical changes to the sampling equipment, to eliminate the airflow and thus the bias conditions significantly. The accounting period that followed the phased upgrading process showed that the accounting between the smelter and base metal refinery had been restored to within statistical limits (difference between physical and theoretical stock below 5% relative to theoretical stock). Keywords sampling, metal accounting, Vezin sampler, sampler bias.

Jan 1, 2014

The roasting of sulphide ores and concentrates is often the first step in the production of metals or chemicals. In many processes, the production of sulphuric acid is viewed as a by-product, while in some plants production is an important economic factor. Regardless of the purpose, a pyrite roasting plant consists of mainly three plant sections: roasting, gas cleaning and sulphuric acid. With the addition of air, the pyrite concentrates are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600 - 1000° C. After cleaning and cooling, the sulphur dioxide in the roasting gas is further processed to sulphuric acid. Two types of reactors are used depending on the application: stationary or circulating fluid bed . For over 60 years, Outotec has progressively been developing the principle of fluidised bed technology in several different reactor types for a multitude of process applications. The versatility of the fluidised bed reactor system has manifested itself in the treatment of minerals, including solid fuels, and for metallurgical processes both in the ferrous and non-ferrous fields. Process applications have included roasting, calcining, combustion and charring of coals, as well as off-gas treatment. This paper provides a summary of the pyrite roasting technology currently used along with a simple cost comparison of pyrite roasting and sulphur burning processes.

Jan 1, 2009

The roasting of sulphide ores and concentrates is often the first step in the production of metals or chemicals. In many processes, the production of sulphuric acid is viewed as a by-product, while in some plants production is an important economic factor. Regardless of the purpose, a pyrite roasting plant consists of mainly three plant sections: roasting, gas cleaning and sulphuric acid. With the addition of air, the pyrite concentrates are transformed into solid oxides and gaseous sulphur dioxide at temperatures of 600 - 1000° C. After cleaning and cooling, the sulphur dioxide in the roasting gas is further processed to sulphuric acid. Two types of reactors are used depending on the application: stationary or circulating fluid bed . For over 60 years, Outotec has progressively been developing the principle of fluidised bed technology in several different reactor types for a multitude of process applications. The versatility of the fluidised bed reactor system has manifested itself in the treatment of minerals, including solid fuels, and for metallurgical processes both in the ferrous and non-ferrous fields. Process applications have included roasting, calcining, combustion and charring of coals, as well as off-gas treatment. This paper provides a summary of the pyrite roasting technology currently used along with a simple cost comparison of pyrite roasting and sulphur burning processes.

Jan 1, 2009