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By J. Etcheverry, E. Seguel, R. Díaz, F. Parada, R. Parra, E. Balladares

A thermodynamic and kinetic model is proposed to explain the formation of bornite, chalcopyrite and magnetite during partial roasting of enargite-containing copper concentrates. The proposed mechanism involves solid-solid-gas and solid-gas reactions between chalcocite, pyrrhotite, gaseous sulfur and oxygen. The formation of bornite could be explained by a two-step reaction: the first one involving the formation of chalcopyrite by a reaction between Cu2S, FeS and gaseous sulfur, followed by a second step in which the newly formed chalcopyrite reacts with additional chalcocite to form bornite. Although thermodynamically the direct formation of bornite is more favorable than that of chalcopyrite, the lower diffusion kinetics of bornite formation could explain the preferential formation of chalcopyrite. If the reaction occurs with stoichiometric chalcocite and pyrrhotite in the presence of gaseous sulfur to form chalcopyrite, no bornite is formed, while for the stoichiometric reaction between chalcopyrite and chalcocite in the absence of sulfur, only bornite is formed. For the formation of magnetite and chalcopyrite the mechanism could involve the partial reaction of chalcocite and pyrrhotite in the presence of oxygen. The proposed model is thermodynamically consistent with the experimental results obtained in laboratory and pilot plant. INTRODUCTION The processing of high-arsenic copper concentrates with over 0.7 wt.-% arsenic by conventional smelting-converting normally require an additional arsenic removal step to reduce arsenic content to levels below 0.2–0.3%. One of these high-arsenic copper concentrates is the one produced by the Ministro Hales Division (DMH) of CODELCO, which has the typical chemical composition shown in Table 1. Enargite (Cu3AsS4), chalcocite (Cu2S) and pyrite (FeS2) are the main mineralogical species present in these concentrates, with over 75 wt.-%, as shown in Table 2. Partial or “neutral” roasting of these concentrates under controlled temperature and partial oxygen pressure conditions at 923–993K (650–720ºC) can remove up to 95% of the arsenic as As2S3 (As4S6), which has a high vapor pressure under these conditions, leaving a calcine with low residual arsenic. In copper concentrates, arsenic is present generally as enargite and arsenopyrite. This compounds as well as others such as pyrite and covelite, decompose readily above 770 K (500ºC), releasing, in addition to gaseous arsenic trisulfide, gaseous sulfur which by oxidizing to SO2 generates most of the heat required by the process.

Jan 1, 2019

By B K. Da, S A. Balaji, G P. Roy, T K. Dutta

The raw material handling complex at the Durgapur steel plant provides iron ore, crushed coke and flux to two sinter plants. Either some facilities were not envisaged or not properly designed before the project stage which caused problems during operation of the plant. The absence of an in situ roll turning facility, used to increase maintenance activities for disassembly, transportation of rolls to central machine shop and assembly of rolls, led to decreased crusher availability and increased activities for the maintenance crew. The provision of a smaller vibro feeder/screen in place of a suitable sized screen caused jamming of the screen deck, adversely affecting screening efficiency and the crushing index of crushed coke. Some design modifications and developmental work was undertaken, such as the development and installation of an in situ roll turning facility in the existing limited space, achieving low feed (0.1 - 0.2 mm/rev), lower cutting speed of 30 - 40 m/minute for 350 BHN hard roll, which was also a difficult engineering challenge to bring within the tolerable limit of vibration. This was successfully achieved. Modifications to the screen deck, introduction of differential speed crushing and modification to the vibro screen and vibro feeder for uniform distribution of feed have been incorporated. These innovative design modifications to the in situ roll turning have led to a drastic decrease in maintenance activities and an improvement in the crushing index. Modifications to the screen have resulted in the elimination of jamming and improved screening. Modifications to the vibro screen before the primary crushers and to the vibro feeder before the secondary crushers have prevented excessive wear in the central portion of rolls, ultimately leading to increased roll life. Incorporation of differential speed crushing has resulted in an increased crushing index and decreased generation of micro fines. All the above modifications have led to distinct improvements in equipment availability, increased roll life and a decrease in maintenance activities and improvement in crushed coke granulametry, ultimately resulting in improved productivity and quality of iron ore agglomeration at the sinter plant. The innovative design modifications mentioned above are discussed in detail in this paper.

Jan 1, 2005

By R. ?. Shishmarjov, Yu. ?. Davidenko, S. V. Bukhalov, ?. S. Baksheev, M. S. Shkirya, N. ?. Aikasheva, D. V. Bogdanovich, ?. Yu. Faustova

"The goal of prospecting operations in the Republic of Altay was to locate gold-sulfide-quartz mineralization. For this purpose we applied the technology of electromagnetic sounding and induced polarization (EMS-IP). These operations resulted in localizing promising sites with presence of sulfidization. The EMS-IP method proved to be highly efficient amongst other prospecting methods targeted at recognizing zones of sulfide mineralization making up 91%, considering that in more than half cases the ore intervals were the case. In the Yakutian diamondiferous province the EMS-IP technology was approbated during three field seasons to accomplish the assignments on searching for kimberlite bodies under conditions of various geological types. As a result, the reference objects were distinguished, and geoelectric parameters of kimberlite pipes of explosion were defined.INTRODUCTION In the time span 2015-2016 in Gorny Altay the EMS-IP technology was approbated in the Novokuznetsk area. The on-land areal geophysical survey was performed by EMS-IP method applied to identify, outline and locate promising sites with Au-Ag-bearing polymetallic mineralization within surveyed areas. Compared to the hosting rocks, the sulfides contained in polymetallic mineralization are typified by low specific electrical resistivity (SER) and high polarization. The areal survey conducted via EMS-IP method provided spatial characteristics of searched object. From July 2016 to August 2017 our expedition group carried out serial test works and laboratory investigations intending to define performance capabilities of EMS-IP technology in searching for kimberlite bodies under conditions of diverse geological types. The prerequisites for serial work were operations accomplished at the «Listvenichny» site lying 35 km away from Mirny town in the Sakha Republic (Yakutia), where the EMS-IP technology was probed for locating position and measuring geoelectric parameters of tuff pipe «Buardakhsky». After successful completion of operations it was decided to evaluate geoelectric parameters of kimberlite pipes of explosion."

Jan 1, 2018

By Deborah A. Kramer

This Bureau of Mines report presents a cost estimate of the Bayer process, which is used for virtually all cell-grade alumina production. The report will serve as a reference point to determine the economic merits of processes that have evolved from Bureau of Mines investigations on technology for producing alumina from domestic nonbauxitic raw materials. The Bayer process involves dissolving the alumina present in bauxite in a caustic solution at high temperature and pressure. After the un- dissolved impurities are removed, the solution is seeded to produce an alumina trihydrate precipitate. This precipitate is filtered, washed, and calcined to produce the cell-grade alumina product. This cost estimate is for a plant producing 1 million tons of alumina per year. The estimated operating cost is approximately $250 per ton of alumina.

Jan 1, 1983

By Alfred Bodenlos

El presente texto señala los depósitos de plomo, zinc encontrados en la mina Huallpac, Macón, Cerro Plumisa; los cateos del área de la laguna Shagallán, Uchco, cateo del cerro Cieren y la mina Buena Casma y Mangán, pertenecientes a la Cordillera Negra, ubicado en Ancash, Perú.

Jan 1, 1958

By T. K. Mukherjee, C. K. Gupta

"The importance of the processing of secondary resources such as solid industrial wastes and liquid effluents as well as byroducts for the recovery of the associated metal values hardly needs any elaboration. Such processing contributes in no small measure towards the augmentation of the availability and the supply position of resources. As an added benefit, it leads to a reduction in environmental pollution caused by the undesirable waste materials. As some typical examples of secondary resources in the Indian scenario, mention can be made of spent catalysts, metal/alloy scrap, ash, consumed batteries, flue dust, slag, sludge and slime, pickling solutions, spent acids, plating rinse solutions, spent etchants, waste water from synthetic fibre manufacture and from tanneries etc .. These wastes constitute a source of a variety of non ferrous metals. In the processing of secondary resources like these, the techniques of hydrometallurgy such as solvent extraction playa pivotal role.This paper outlines the efforts made to use solvent extraction to recover (1) base metals such as copper, zinc, nickel and cobalt from a number of secondary resources like cake, and sludge (2) refractory metals like molybdenum and vanadium from sulphidic byproducts and spent catalyst and (3) nuclear metal like uranium from phosphoric acid. In the case of base metals, process flowsheet involving the use of acidic extractants such as DEHPA and PC88A have been optimised. The problem of iron removal from the leach liquor, which influences the metal recovery process significantly, has drawn a special emphasis. In the case of refractory metals, basic extractants like Alarnine 336 has been pressed into service to produce kilogramme quantities of pure salts of molybdenum and vanadium. Finally, the paper gives a brief account of plant experience in recovering uranium from phosphoric acid, using a solvent system comosed of DEHPA and TOPO."

Jan 1, 1996

By Leonardo Silva Motta

O carbureto de cálcio tem sido empregado em novas tecnologias para desoxidação e dessulfuração de aços de maneira crescente. A metodologia consiste na realização de um cronograma de projeto contendo dez atividades. Nos últimos anos houve aumento em cerca de 30% na utilização de carbureto de cálcio na metalurgia secundária das usinas brasileiras. Além desse expressivo aumento, vários trabalhos técnicos são apresentados todos os anos atestando as eficiências técnica, energética e financeira do carbureto de cálcio na produção de aço.

Jul 30, 2018

By G Bubner, C Gaughan

Magnetite mineralisation within the South Middleback Range has been known since the early 1930s; however, it was not until 1989 that BHP (then owners of the Middleback Ranges mining leases) drilled 10 700 m of diamond core into what was then known as the Iron Duchess low-grade deposit. In 2002 a review of Iron Resources left in the Middleback Ranges and the identification of downstream processing benefits using magnetite as a primary feed source led to the commencement of an 18 000 m resource drilling program of the high-grade core of the Iron Duchess low-grade orebody (renamed the Iron Magnet deposit). This paper describes the geology, processes and procedures used since drilling recommenced in early 2003. The Iron Magnet deposit is located 53 km southwest of Whyalla in the South Middleback Range, South Australia. It is a Paleoproterozoic stratabound magnetite deposit that lies down-dip and lateral to the Iron Duke hematite deposit, hosted within the Lower Middleback Iron Formation of the Hutchison Group meta-sediments within the Cleve subdomain of the Gawler Craton. Magnetite bearing host units within the Lower Middleback Iron Formation can be divided into a æmixedÆ basal sequence, a lower iron carbonate unit, a middle iron talc unit and an upper iron silica unit, all units grading up sequence and laterally into one another. The magnetite mineralisation is hydrothermal in origin. The strongest consistent mineralisation coincides with the iron carbonate unit, and the hematite orebodies of the Iron Duke are interpreted to represent up-dip supergene enrichment of the same unit. The Iron Magnet occurs within a large-scale parasitic syncline-anticline pair on the west limb of a larger syncline. Major bounding north-south shear zones occur on the east and west sides of the deposit. Cross-cutting west-northwest, northwest, northeast and east-northeast trending faults displace mineralisation. The commencement of drilling in 2003 lead to the migration of geological and geochemical databases, re-logging and re-assaying of all old cores that intersected the deposit, updating of logging codes and procedures, and strict Qa/Qc procedures to ensure the study satisfied JORC standards. External consultants were used for auditing and bench marking. The strong geophysical responses of magnetite and the wealth of close spaced ground magnetic and gravity data already completed over the Middleback Ranges allowed for refining of drill hole targets for the drilling program. It also provided an indirect method for ascertaining magnetite grade and tonnage volumes.

Jan 1, 2005

By G Richmond, J R. Glen

Western Metals Mt Gordon Operation is a copper mine and processing plant situated 120 kilometres north of Mt Isa. The unique Mt Gordon copper process utilises a whole of ore acid/ferric pressure leach to produce copper cathode from the Esperanza massive sulfide copper orebody. Esperanza ore contains chalcocite, covellite and minor chalcopyrite hosted in a massive pyrite matrix. These ore stocks will be depleted in late 2003. Recently the process circuit has been upgraded to allow the treatment of lower grade Mammoth ores. These include the installation of a ball mill to complement the existing SAG mill, a single stage rougher flotation circuit and a tailings thickener. The leach bleed neutralisation plant was also upgraded at this time. Commissioning of these new circuits occurred in March 2003 and involved all the challenges of ensuring current production levels were successfully maintained while new process steps were incorporated into the whole circuit. This paper explains the background flow sheet of the patented Mt Gordon process and the reasoning behind the enhancements required for an already successful copper leaching circuit. Included are discussion of the influences of the new ores on individual process components such as comminution, leach chemistry and solid/liquid separation. Longer term ore processing options are also discussed.

Jan 1, 2003

By F. B. Plummer

PROGRESS during 1940 in oil-production technology has been confined largely to a steady advancement in practices inaugurated in previous years, rather than the introduction of any new startling process or technique. The usual changes, improvements and additions in production equipment have been introduced. An increased attention to, and interest in, research has been noteworthy, resulting in improved efficiency in operation of oil wells. control, utilization of reservoir energies and reduction of production costs.

Jan 1, 1941

By Moresby J. F

Segregation roasting was used to recover more than 85 per cent of copper from crushed, minus 14 mesh refractory furnace-lining bricks. A plus 14 mesh fraction: which was high in copper, could be recycled directly to the smelter, giving an overall recovery of approximately 90 per cent. An oxidation roast at about 700°C was necessary, before segregation roasting, to convert copper sulphides and copper metal to sulphates and oxides. Withsegregatron temperatures in the range 600°-650°C the quantities of solid carbon and NaCI required are 2-5 per cent and 1 per cent respectively. P.V.C. coating from scrap copper wire can be used instead of NaCl as asource of hydrogen chloride for the segregation reaction.

Jan 1, 1978

By John R. Reigart

The Tri-State district, as its name indicates, is composed of portions of three States, the southeastern corner of Kansas, the northeastern corner of Oklahoma, and an adjacent strip of Missouri east of these portions of Kansas and Oklahoma. An area approximately 40 miles long in a northeasterly-southwesterly direction, and 30 miles wide at right angles thereto, containing minable occurrences of ore at widely scattered locations, comprises the district. However, what has been and is the main productive area, is a strip about 35 miles long and 10 miles wide, which begins at Miami, Okla., as its southern extremity and runs in a northeasterly direction through Commerce, Picher, and Hockerville, Okla., Baxter Springs and Galena, Kans., and Joplin, Webb City-Carterville and Carthage, Mo. Almost the entire present production comes from the area between Commerce and Baxter Springs.

Jan 1, 1932

By Eduardo Reis de Oliveira

O alumínio por suas excelentes características físico químicas é empregado na indústria civil, automotiva, naval e aeroespacial. As características mecânicas dos sistemas solidificados dependem do arranjo microestrutural, mais especificamente do tamanho de grão, espaçamentos celulares ou dendríticos, das heterogeneidades de composição química, do tamanho, forma, distribuição das inclusões e das porosidades. A fusão de metais e, consequentemente, a solidificação, são etapas importantes na obtenção dos metais. Neste estudo iremos investigar a solidificação vertical ascendente em regime transiente do sistema Al-Mg. Está análise investigou experimentalmente o efeito das composições e dos superaquecimentos nas microestruturas solidificadas. Durante a fabricação dos lingotes, foram mapeadas a solidificação de cada liga. As microestruturas obtidas evidenciaram um aspecto essencialmente dendrítico, verificados através da microscopia óptica. É estabelecido no trabalho uma comparação entre os espaçamentos dendríticos primário (EDP ou ?1) e secundário (EDS ou ?2) em relação adição de 1, 3 e 5% de Mg e com patamares de superaquecimento (?TV) variando em 20, 40 e 60ºC.A variação do superaquecimento e da composição química dos lingotes teve influência nos espaçamentos dendríticos, verificados nas medições transversais e longitudinais dos lingotes. Para cada posição analisada foram obtidas uma média dos valores e o respectivo intervalo de dispersão.

Oct 30, 2017

By Filipe Augusto Vasconcelos Guimarães

O presente artigo discute as interferências causadas pelo incremento gradual de umidade nos minérios produzidos atualmente, especialmente aqueles produzidos diretamente para carregamento. O aumento de umidade representa um desafio constante no transporte e tratamento dos materiais produzidos, uma vez que a simplificação dos fluxogramas pode também significar uma importante parcela na redução dos custos, tema hoje primordial na sobrevivência de qualquer empreendimento de minério de ferro. A utilização de reagentes auxiliares para ajudar no tratamento e transporte desses materiais pode significar a diferença entre a manutenção ou o fechamento de uma mina.

Aug 16, 2017

By C. C. Shale

Current-voltage relationships for air at high temperature in negative corona are compared with relationships predicted by theory. Deviations are discussed. Eased on the latest theoretical concept of electron detachment from negative ions and recent findings in basic research on free electron gases, results of applied research show the existence of free electrons in air at high temperature and high field strength-to-pressure ratios.

Jan 1, 1967

By J. F. Barkley

The work covered in this report was done to meet the requests from many Government agencies for information on alleviating sludge difficulties in No. 6 (Bunker C) fuel-oil storage tanks. Accumulated sludge at times caused serious loss in tank capacities; pumps became overloaded or lost suction; strainers often required very frequent cleaning; fuel-oil heaters in some instances became fouled and inefficient; and gobs of sludge that passed the strainers interfered with good combustion. The requests also included questions regarding the usefulness in general of oil "additives" for preventing sludge and the relative merits of the many trade-named additives being marketed. Realizing that preventing such difficulties would result in substantial savings to the Government, an investigation was begun with the limited funds avail-able. Although various claims are made for No. 6 fuel-oil additives other than preventing sludge, only an investigation as regards the storage tank-sludge problem has been possible.

Jan 1, 1955

By Poul Hansen

"In mid-I986, a world-class mining enterprise was created in British Columbia, bringing together the copper mining operations of Lornex Mining Corporation and Cominco into a new entity, Highland Valley Copper. This paper will focus on the background and rationalef or the formation of this partnership, the resulting operating changes and the productivity and cost benefits expected.IntroductionSince the deterioration of the world copper industry in 1981, the future of the Lomex and Cominco mines in the Highland Valley of British Columbia looked increasingly precarious. Despite the expansion of the Lomex mill complex in 1981 to one of the world's most cost-efficient copper and molybdenum concentrators, persistent low metal prices had made the remainder of the ore in the Lomex orebody marginally economic and had significantly foreshortened the expected life of the operation.Cominco had acquired the Bethlehem Copper assets in order to consolidate its ownership of the Valley orebody, and was feeding the Bethlehem concentrator with ore from the Valley orebody. In spite of the high grade and free-milling character of the Valley ore, profitability of the Cominco operation was severely restricted because of the limited capacity of the Bethlehem concentrator and its location high on the hillside above the orebody."

Jan 1, 1987

By Robinson KJ

There has been much debate in recent years regarding the number of Geology (Earth Science) graduates produced in Australia. The key variable has commonly been assumed to be the placement of graduates in the mineral and petroleum industries. Although not wishing to deny the importance of this element, we contend that Geoscience studies should be given to a wider variety of graduates. The essence is to make students and future citizens more environmentally aware. INTRODUCTION Geoscience is fundamental to exploration and to the well-being of the minerals industry and hence the Australian economy. The value of mineral primary products exports for the past three years has been: 1895 $15.3 billion 1986 $14.8 billion 1987 $16.3 billion (Data source: B.M.R) The mining industry supplies about 40% of Australia's export earnings. However the overall value of Geoscience to the Australian economy is much greater. At the opening of the ANZAAS conference in Townsville during May 1987, Sir Bruce Watson , Chairman of the Mt. Isa Mines Ltd., made a plea for a national re-examination of the way science is taught in secondary schools. In particular he emphasized the point that the community should be more aware of the importance of Geoscience and the value of the mining industry to Australia.

Jan 1, 1989

Very little has been written about the discovery and early history of prospecting of ironstone deposits in the Iron Knob-Middleback Range area of South Australia, the main source of supply of ironstone (hematite) for the Australian steel industry, and scanty though the record is, much of it is wrong or misleading.With the help of several people, to whom acknowledgement is made at the end of the paper, the writer has unravelled some of the story, but not the whole story. It is hoped that publication of this paper will stimulate interest in others, who may be able to supplement this account from family records, from the files of newspapers, or from archives.

Jan 1, 1969

By A Yáñez, P Vallejos, R Grau, J Yianatos

In flotation cells, especially in large flotation units, froth management is a crucial variable that should be considered during the design phase or optimised to improve the performance of existing flotation circuits. This paper presents a simulation evaluation of the effect of launder design on the metallurgical performance of an industrial flotation circuit consisting of five TankCell® e630 (630 m3 ) cells in a Cu rougher duty. This analysis was carried out using a new industrial simulator, which was built on a wide database collected from many industrial concentrators. This tool is currently incorporated into HSC Chemistry® software and allows evaluation of the effect of launder design on mineral froth recovery, water recovery, entrainment, and other variables to be quantified. The industrial flotation circuit was evaluated under different launder design scenarios, considering an actual flotation circuit that includes TankCell® e630 cells for calibration and as a reference (baseline). Firstly, two different designs were evaluated in the full circuit: a standard launder design and a new launder technology. It was found that the new launder technology enabled improvement of the mineral recovery along the circuit, mainly for coarse particles, due to the improvement in froth mineral recovery. Next, the partial upgrade of the launder design along the circuit was analysed. Thus, the new launder technology was evaluated in the first and the last two cells of the bank. The results showed that upgrading the launders in different cells along the circuit delivered an increase in the final recovery with respect to the baseline, with a partial impact on the concentrate grade. However, these changes are less than those when evaluating the full upgrade scenario. A partial launder upgrade either in the first or last two cells of the bank showed similar final recoveries, but the latter enabled a slightly higher concentrate grade (about 1 per cent higher) to be achieved. Finally, the evaluation of launder design using the industrial simulator made it possible to estimate its effect on variables that are not commonly obtained from plant surveys, including froth recovery per particle size, collection recovery per particle size and liberation, gangue entrainment and bubble loading grade.

Aug 24, 2022