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By C. Dupuis, P. Waite, S. Leboeuf

Casthouses throughout the aluminium industry commonly use chlorine gas as a fluxing agent for furnace and in-line treatment of molten aluminium alloys. Its positive impact on the removal of alkali elements and non-metallic inclusions is well known. Nevertheless, the elimination of its use is highly desirable due to the safety and environmental risks associated with storage and handling. Over the past decade, the aluminium industry has significantly reduced its chlorine consumption. This has been achieved by maximizing the chlorine gas utilization efficiency during metal processing, and by the chlorine replacement for crucible and furnace metal treatment applications. Operation of sealed in-line treatment units without chlorine is now possible, but with lower or inconsistent removal efficiency penalties for alkali and inclusions respectively. This paper reviews the progress made at Arvida Research and Development Centre regarding the reduction of chlorine and the development of an alternative to chlorine for in-line metal treatment without penalizing the metallurgical performance.

Jan 1, 2006

By Alexandre Aparecida Morais

No processo de lingotamento contínuo de placas, o controle de fluxo de aço líquido entre o distribuidor e os moldes pode ser realizado através de tampão refratário ou válvula gaveta. Quando se usa o controle via tampão refratário, aproveita-se o mesmo para reter um volume mínimo de aço no distribuidor, visando efetuar a partida do veio. Este volume de aço é importante para evitar o congelamento da primeira porção de aço e prevenir o arraste de impurezas existentes no fundo do distribuidor para o molde. Já quando se usa o controle via válvula gaveta, para acumular o volume de aço necessário, utiliza-se de outros “artifícios”, como o uso de anteparos metálicos em forma de bujões, cuja eficiência é limitada. Visando melhorar o desempenho de partida das máquinas com controle de fluxo de aço distribuidor-molde, via válvula gaveta, desenvolveu-se o chamado tampão flutuante de fibra cerâmica, cujas funções principais são: equalizar o nível de aço para proporcionar uma partida normal e impedir que impurezas arrastadas pela primeira porção de aço, se dirijam para os veios. Este trabalho mostra o desenvolvimento pioneiro desta técnica para distribuidores de aços planos na ArcelorMittal Tubarão.

Jul 30, 2018

By J. Rothschild

I would like to thank the Society of Mining Engineers for inviting me as well as the other distinguished panelists to spend a morning reviewing and discussing the handling and shipping of industrial minerals. I also would like to thank my management, Cometals. Inc. for permitting me to take time out from the daily hectic pace of marketing and trading to share with you some of our experiences and expertise. Cometals, Inc. is a wholly-owned subsidiary of Commercial Metals of Dallas. The transportation and handling costs of industrial minerals frequently are a major component of the value of the goods marketed and, therefore, it is only natural that close attention should be paid to them. Many of the industrial minerals require special handling to assure that the material reaches the consumer without being contaminated or getting wet. I invite you to accompany me through the various steps involved in "delivering the goods" to the consumer.

Jan 1, 1989

By José Adachi

La ventilación de minas es un proceso relacionado a la dinámica de la mina que genera el acondicionamiento del aire circulante a través de las labores subterráneas. Como tal, los requerimientos de la mina se adecúan de acuerdo a la estructura física de la misma. En consecuencia, no existe un sistema de ventilación estático puesto que los sistemas requieren de constantes monitoreos y ajustes para alcanzar una ventilación óptima. Así, el presente trabajo señala los aspectos importantes del diseño de ventilación principal de la mina Condestable realizado entre el período de 1992 y 1993 por encargo de la compañía minera. La metodología empleada comprende mediciones de campo y el cálculo de requerimientos del caudal. Asi también está la construcción del modelo de red de ventilación y el diseño del nuevo ciricuito con ventilación forzada.

Nov 24, 1993

By Donald Mc Laughlin

El presente texto revisa los antecedentes y la capacidad metalúrgica para la instalación de una planta de fundición. Para ello, se revisa la fuerza metalúrgica, coke metalúrgico, inversiones, mano, capital de trabajo, producción y rendimientos, balance económico, efectos de las fluctuaciones de precios en el balance, económico financiación, fertilizantes y ventajas de la central metalúrgica.

Jan 1, 1959

By K. E. Harrison

The acid rain legislation has passed into law. This new law has caused the power generation community to investigate alternative methods to obtain compliance with the new legislation. One thing all of the power companies have concluded is the answer is not easy. Do we switch fuels to burn all low sulfur compliance coal? Maybe possibly only partial desulfurization by means of a dry sorbent system? Or, finally, maybe a wet scrubber system? Whatever the choice, the power community needs to investigate all of the alternatives. In 1988, ICF Kaiser Engineers, Inc. (ICF KE) responded to a request by the U.S. Department of Energy for the engineering development of advanced physical fine coal cleaning. ICF KE responded and was awarded a contract to conduct a multi-task program to develop an advanced flotation system to eliminate pyritic sulfur and retain as much energy as possible. ICF KE assembled a team that included members of industry, academia, and industry research organizations to conduct this multi-task program. The program includes sixteen (16) tasks. This team had personnel to help solve some of the anticipated problems and to provide industry prospective on the viability and commercial potential for any concepts proposed. The primary team consists of a major coal producer, Babcock and Wilcox, Eimco Process Equipment Company, and Virginia Polytechnic Institute and State University.

Jan 1, 1992

By F. L. Bazzanella

Cyprus Pima has two concentrators, one with a conventional crushing-grinding circuit and the other using semi-autogenous grinding followed by ball mills.

Jan 1, 1978

By D. E. Ranta

Orebodies with intricate three-dimensional shapes (such as porphyry molybdenum deposits) are difficult to model using geostatistics or other computer-assisted methods. The strong trends in their spatial grade distributions occur as mathematically complex shapes and prevent the customary assumption of local stationarity that is required for accurate ore reserve estimation. "Zoned Kriging", a new method developed by AMAX, solves this problem directly by using the geologist's interpretation of the ore zones as a parameter in the kriging equations. The geological basis and methods used in the Climax ore zoning technique are reviewed and discussed relative to their application in zoned geostatistical modeling. The Zoned Kriging technique is described and demonstrated using data typical of mineral deposits.

Jan 1, 1984

By Yuexin Han, Jie Liu, Shuai Yuan, Yanjun Li

"In order to improve recovery efficiency of iron minerals from iron ore tailings and to reduce its connected environmental pollution, this article investigated the reducing roasting of iron ore tailing in a laboratory fluidized magnetization roasting reactor to optimize the roasting method and conditions. The examined parameters included roasting temperature, roasting time and reducing atmosphere. The parameters evaluating magnetizing roast efficiency and theoretical value were determined. X-ray diffraction (XRD) analysis was used to investigate the conversion of iron phase after roasting. The results show that the best magnetizing roast conditions are roasting temperature of 540?, holding time of 15min, and CO concentration of 20%. The magnetization conversion ratio of roasting products is over 80%, under the best magnetic separation condition, the concentrate grade of iron is 65.61 % and the recovery of iron is 83.77 %. The XRD analysis shows that Fe exists in hematite and siderite before roasting and exists in magnetite after roasting. The technique not only recovers the iron minerals from tailings with good economic benefit, but also reduces the environmental pollution of tailings accumulation.INTRODUCTION Iron ore tailings are the solid wastes generated during the beneficiation process of iron ore concentration and are one of the main pollution concerns in the mining industry (Das et al., 1996). Continuous development of the iron and steel industry has led to the increasing amount of iron ore tailings; there are over 300 million tons of iron ore tailings discharged per year (Rao et al., 2016). The huge amount of stockpiled iron ore tailings brings a series of environmental and social problems. Comprehensive utilization of iron ore tailings can not only reduce environmental load but also conserve resources, promoting sustainable development of the society. In recent years, iron ore tailings as secondary resources have received considerable attention in many countries in the word and numbers of studies on utilization of iron ore tailings were carried out, such as recycling the valuable minerals (Datta et al., 1996; Jia et al., 2013; Panda et al., 2018), used in construction material compositions as alternative source of raw materials (Das et al., 2012; Zhou et al., 2012; Luo et al., 2016) and other utilization. The iron minerals were recovery by magnetization roasting (Rao et al., 2016; Yang et al., 2013; Yang et al., 2011) and flotation (Kumar and Mandre, 2016). By comparison the reduction roasting has more advantages, but it was found that the conventional roasting equipment was inefficient, high energy consumption and un-economically applied on an industrial-scale."

Jan 1, 2018

By A. G. Ulsoy

In recent years there has been an Increasing Interest In the application of automatic control theory to mineral processing systems, and numerous applications of mineral process control have appeared in the literature. A general approach to the synthesis of mineral process control systems is presented. The first phase of the control system design consists of specifying the control objectives, process variables and their interactions; these topics will be discussed with specific reference to mineral processing. The second phase Is con¬cerned with selection of control strategies algorithms, instrumenta¬tion, and other components of the control system and is discussed at length. These concepts are then illustrated by a flotation control case study.

Jan 1, 1981

By Dmitriy Makarov

The paper presents the modeling and analysis of oxidation of pyrite copper-zinc ore samples from the Letnee, Yaman-Kasy and Valentorskoye deposits. It is found, that the oxidized samples contain copper and zinc sulfates that are leached under the sample and water contact. It is shown, that sulfide floatability is decreased by the longer-term oxidation.We advise to improve nonferrous metals recovery by joint leaching and ultrasonic treatment of oxidized compounds. Study of the geotechnological processes of non-ferrous metal extraction, on the basis of two copper-zinc ore deposits shows, that heap leaching is of little use for the ores of the Letnee deposit. Leaching results for the Yaman-Kasy ore showed more promise.

Sep 1, 2012

By John B. Gayle

The probable inadequacy of physical tests of coke for the purposes for which they are made has been a subject for discussion for many years. However, little has been published in this connection, even though most workers in the field believe that the physical properties of coke are of major importance in its utilization in the steel and allied industries. In fact, the reproducibility of the recognized tests is largely unknown or can only be approximated. This situation occasions many difficulties when attempts are made to judge the coke-production qualities of various coals or coal blends. During World War II the Coke Production Committee, composed of representatives from industry and the Solid Fuels Administration, concluded that study of existing testing methods and possible improvements would be of material assistance in answering questions relating to coke quality. Since that time the Bureau of Mines has taken samples of coke produced in industrial slot-type coke ovens in connection with studies aimed at extending coking-coal reserves by adding to the list of sources known to be suitable for this purpose. Testing procedures on these cokes were arranged so that the data obtained would yield information on (1) the degree of precision of tests commonly used in the industry, (2) the causes of the known poor reproducibility in several of the physical tests, and (3) possible improvements or modifications of existing physical testing procedures.

Jan 1, 1953

By B. J. Arnold

Coal blending inherently means homogenizing a mixture of coals so that, overall, the properties of the blend meet some specifications for maintaining power plant performance and emission requirements. In common practice, however, coal blending is at best coal mixing. If necessary, more sophisticated blending systems can produce a more homogeneous feed by using accurate weighing devices and on-line coal analyzers coupled with sampling systems. Blending can be accomplished at the mine, on stockpiles, and from bins, bunkers, and silos.

Jan 1, 1994

By H. P. Hermance

The Ore Hill zinc-lead mine in Grafton County, N. H., was investigated by the Bureau of Mines from March to July 1943 and from August to October 1944. Fourteen holes with an aggregate bore of 4,899 feet were diamond-drilled, the old workings were unwatered and sampled to an inclined depth of 250 feet, and the tailings dumps were surveyed and sampled. The deposit at the Ore Hill mine comprises a bedding-plane vein of massive sphalerite and galena with subordinate chalcopyrite and pyrite in a series of interbedded metasedimentary and metavolcanic schists about one-quarter mile east of their contact with the intrusive Baker Pond gneiss. The property was first opened about 1850 and was active at times to 1914. Production records are not available, but the output is believed to have been considerable. In 1944, leasers recovered a marketable mica product from mica schist from the dumps and certain outcrops. This report describes the work performed in the Bureau's investigation and presents the data obtained.

Jan 1, 1948

By J. Snowberger III

Rhenium is a valuable and extremely rare chemical element with unique chemical properties. It is extracted commercially as a byproduct from the processing of molybdenite associated with porphyry copper ores. There is a present interest in recovering rhenium from copper pregnant leach solutions (PLS) produced by copper heap and stockpile leaching. These solutions contain rhenium at very dilute concentrations, typically in the 1 mg/L concentration range. This paper describes laboratory column ion exchange experiments to extract rhenium from these solutions using weakly basic anion exchange resins and actual plant PLS from two operating mines. The dynamic loading and elution behavior of Re on Purolite® A170 and A172 is discussed.

Feb 23, 2014

By Jun Yi

In this paper, single-component gas sorption and transient diffusion processes are described within coal matrix exhibiting bimodal pore structure. The coal matrix is treated as a poroelastic medium manifesting swelling and shrinkage effects due to the sorption of gas under effective overburden stress. Gas transport is considered Fickian with molecular (bulk) and surface diffusion processes simultaneously taking place in the macro-and micropores of coal, respectively. The numerical formulation is intended to be explicit in nature to investigate the influences of sorption phenomena on the macropore volumes and on the overall gas transport for the cases of gas uptake by and release from coal. Results of the study show the presence of hysteresis during a sorption?desorption cycle of the gas. It is also found that the overall gas transport takes place at a rate significantly less than that in the macropores only. Thus the existence of a retardation effect in the overall gas transport is concluded. This retardation effect is primarily due to the micropore resistances, in particular gas adsorption, and is independent of the changes in the macropore volumes. It is shown that macroporosity of the coal matrix may change during gas transport due to combined effects of pressure and sorption-induced swelling or shrinkage of the coal. It is estimated that the macroporosity variation is non-uniform in space and time, as it is expected in reality, and typically taking values less than ±10 percent of the initial porosity.

Jan 1, 2009

By J. C. Edwards

The Bureau of Mines developed a mathematical model for analysis of the impact of scrubber bed length, porosity, and gas flow rate on the absorption of C02 in a breathing apparatus. The model accounts for the decrease in available absorbent through chemical conversion. The pre-dicted efflux of C02 from a canister containing LiOR compared favorably with measured values reported elsewhere. It was determined from a com-putational study that the time for breakthrough of C02 at a prescribed level is nearly directly proportional to bed length and inversely pro-portional to gas flow and porosity.

Jan 1, 1987

By A. Boehm

Mineral selective flash roasting (Steiner process) in oxidizing atmosphere was tested successfully for the efficient low intensity magnetic separation of siderite from ankerite and other gangue minerals within the ore of the Steirische Erzberg, Austria. The calcium, magnesium and manganese containing siderite turns selectively into a ferromagnetic oxide phase while ankerite remains paramagnetic. The expulsion of CO2 increases the volume specific surface depending on the selected temperature. Unlike pure iron oxides absorbing SO2 below 530°C, the calcined siderite (enriched in the magnetic product of the Steiner process) acts as a sorbent for SO2 between 500 and 820°C. The effect was studied by thermogravimetric analysis and particle bed tests complemented with neutron thermo diffractometry (D20/ ILL). The energy input was simulated with the help of a tube furnace. The composition of the artificial combustion gas permeating the bed was close to that measured in pilot scale tests (6 % CO2, 12 % O2, 700 vpm SO2). The evaluation of data relating the SO2 variation in the off gas monitored by electrochemical cells to the actual phase composition revealed an intermediate ferrite phase as absorber. During the rapid decomposition in oxidizing atmosphere starting at 500°C the occurring siderite alters to a (CaO, MgO, MnO)Fe2O3 ferrite as an intermediate phase accompanied with sudden SO2 absorption. SO2 disintegrates the ferrite structure forming MgSO4 and MnSO4, taking Fe2O3 as a catalyst. Ankerite (enriched in the non magnetics of the Steiner process) starts to absorb at temperatures above 1000°C forming gypsum. The findings support the SO2 controlled operation of the Steiner process by ?autodesulfurisation?. It explains aspects of the SO2 implementation reactions within off gas recycling in Austrian sinterstrands. Keywords: magnetising flash roasting, neutron thermo diffractometry, SO2 absorption, siderite, ankerite

Sep 1, 2012

By Brian C. Asbury

Gold-bearing quartz veins with auriferou pyritic wall rock alteration haloes at the Komis deposit near Waddy Lake in northern Saskatchewan occur in fractured Archean intermediate volcanic rock flanking a plutonic felsic intrusion. Three ore zones totalling 1.5 million tonnes grading five g/t gold have resulted from a combination of patterns of high density of fracture-filling quartz veins created by contrasting competencies of four predominant rock types and preferential gold deposition in magnetitebearing andesite host rock. Pre-glacial surface weathering remobilized gold from a nearby pyritized intermediateto- felsic dyke to form the EP Zone with a wide variety of supergene accessory minerals. Much of the EP Zone wa eroded by glacial action to forn1 a highly anomalous gold-bearing till dispersion train which facilitated its di covery.

Jan 1, 1986

By Frank B. Fulkerson

Three of the five primary aluminum producers in the Pacific Northwest have facilities in the region to make aluminum mill products. Only one of the three, however, produces a variety of shapes and forms. The principal reason for the lag in development of an aluminum mill products industry was found to be transportation cost. The long range outlook is for expansion, based mainly on growth of the western market for aluminum used in construction, containers and packaging, electrical applications, diesel trucks, mobile homes, and irregation pipe. Consumption of western aluminum mill products in 1985 is projected at 1.1 million tons, compared with estimated consumption of 250,000 tons in 1961.

Jan 1, 1965