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A major problem in the continuous casting of aluminium killed strip steel is the incidence of black and grey lines in the strip surface caused by the alumina inclusions. One place for limiting the number of alumina inclusions is by providing favourable fluid flow conditions in the ladle so that the inclusions float out to the surface or adhere to the ladle wall. In laboratory equipment 20 kg of steel was melted in an alumina crucible of 14 cm diameter in an induction furnace. Deoxidation was carried out while the melt was constantly stirred by argon bubbling. Bubble frequencies were measured at the lance tip using a microphone technique. High speed cine photo- graphy was incorporated to measure melt top surface velocities. Experimental results indicate that the rate of removal of inclusions is a function of both the gas input and the power input. However due to unfavourable surface area to volume ratio, reoxidation of the melt took place. Some other experimental difficulties in working at high temperatures are also discussed such as lance design, melting arrangement and sampling techniques.

Jan 1, 1984

By A S. M A Haseeb

Zircon is the second in abundance among the heavy minerals occurring in the beach sand along the coastal belt of Bangladesh. In this study a detailed characterisation of Bangladesh zircon extracted at the pilot plant of the Bangladesh Atomic Energy Commission at CoxÆs Bazar has been attempted using chemical analysis, X-ray diffraction and optical microscopy. From the chemical analysis it is found that Bangladesh zircon has a purity of 95.88 per cent. The main impurity in Bangladesh zircon is titanium oxide (3.01 per cent). This is followed by iron oxide (0.42 per cent). A number of other oxides are also found. Microscopic study revealed that Bangladesh zircon has an elongated, prismatic shape with pyramidal termination in about half of the grains while the rest are more or less rounded. Some fractured and irregular grains are also found. Bulk sample of Bangladesh zircon in the as-received condition shows a yellowish brown color. However, individual zircon grains are seen to be almost colourless and transparent under polarised light. XRD study confirmed good crystallinity in the sample. Under the microscope it is found that zircon grains constitute 94 per cent while total impurities amount to six per cent in Bangladesh zircon. This result agrees fairly well with the chemical analysis results. Microscopic study identifies oxides of titanium (both rutile and ilmenite) to be the main impurity, in conformity with the findings of chemical analysis. Further, monazite was also identified as an impurity under the microscope. An iron bearing coating is also found on a few zircon grains. Most of the impurities found in Bangladesh zircon exist as discrete minerals.

Jan 1, 2000

By Yamamoto Y, Ohyama H

In case of NATM, mechanical cutting is desirable in view of the original purpose of not spoiling natural ground. As typical tunnelling machines, there are two (2) kinds available: one is "Full Face Excavator" known as TBM (tunnel boring machine), and the other is "Roadheader" known as Part Face Excavator. By the use of the former, accurate profile cut is made possible, but there is a limit in the shape of a cutting section. By the use of the latter, cutting of various sections is made possible, but in order to cut a section economically and accurately, operators are required to have a high level of skill. In this text, we introduce Automatic Controlled Profile Cutting System (hereafter "ACPC" System) developed as a roadheader.

Jan 1, 1987

By Ju Shao-hua

Although nowadays gold extraction methods are very abundant, none of them is satisfying, especially, in the field of heap leaching of low grade gold ore. The traditional heap leaching method of cyanide method plays an inglorious role of badly environmental pollution. In this paper, a bran-new and innoxious method of gold extraction system, metal-ammonium-chloride-ammonia (MACA), was proposed, and also analyzed both thermodynamically and practically. Thermodynamically, according to the principles of simultaneous chemical equilibrium and electronic charge neutrality, the thermodynamics of Au-NH4Cl-NH3-H2O system was studied by using the exponential computation method and through MATLAB programming, and the solid figure of its potential - c(NH4Cl) - c(NH4OH) was drawn. The results showed when the concentrate of ammonia is higher than 0.6 mol?L-1, fAu+/Au is only about -0.2 v. Practically, the leaching results of a cuprous gold ore showed that the extraction of gold can reach to 80% in this system. The preliminary results of reduction of the rich solution with copper and zinc powders showed that with deoxygenizing, the reduction effects were relatively good. These new findings and results have established a theoretical and practical base for developing a new process for heap leaching of low grade gold ores in this system. And the new process owns a series of merits such as, non-cyanogens, nontoxic, broader applicability.

Jan 1, 2006

By E. C. L. Cardoso

Hydrocarbon polymers, as PP, made from cheap petrochemical feedstock are important in many branches of industry. However, they have an undesirable influence on the environment and cause problems due to waste deposition and utilization. Polymeric materials composites account for an estimated from 20 to 30% of total volume of solid waste disposed. Thus, there is a tendency to substitute such polymers by those ones that undergo biodegradable processes. Polypropylene (PP) is a commodity, with high melting point, high chemical resistance, low density, with a balance between physical and mechanical properties and easy processing at low cost. Nevertheless, PP shows limitations for some special applications in automotive industry and civil construction. In order to minimize this deficiency, related to rheological behavior of polymer melt, especially referring to viscosity in processing temperature, a 50% mixture with HMSPP (High melt Strength Polypropylene) was used. PP/HMSPP was blended with 10, 15, 30 and 50% of natural (sugarcane bagasse) and synthetic polymers (PHB and PLA) aiming to partially biodegradable materials. The admixtures were subjected to gamma-irradiation at 50, 100, 150 and 200 kGy and then further assessed by mechanical tests in order to evaluate their degradability.

Jan 1, 2015

By Martin Reyes, Juan Hernández, Julio Cesar Juárez, Isauro Rivera, Ma. de los Ángeles Hernández, Francisco Patiño

The dissolution of Ag contained in metallurgical tailings was studied by adding ions Cu2+ and Zn2+ in S2O3 2- medium. Chemical analysis of mine tailings by cupellation revealed a Ag concentration of 71 g/ton. The XRF and XRD analysis confirmed the preponderance of SiO2 in the mineral matrix. The experimental dissolution process was conducted in alkaline solution using six concentrations of NaOH and five of S2O3 2-, at different temperatures, also using five concentrations of Cu2+ and Zn2+ as a catalyst. The results showed similar values for both systems (96.8% and 97.13%). The ion Cu2+ and Zn2+ increases the dissolution of Ag, and decrease the reaction time of dissolution. Under the conditions used, pH and stirring rate did not affect the dissolution of Ag.

Jan 1, 2015

By Antonio Adel dos Santos, Carmos Antonio Gandra, Fabricio Mazola da Silva Paiva, Vicente Tadeu Lopes Buono

Abstract Usiminas Steel Plant in Ipatinga installed an accelerated cooling device named CLC (Continuous On-Line Control) in 2010, enabling it to supply steels produced by TMCP (Thermo Mechanical Control Process) technology. This technology complements the TMCR (Thermo Mechanical Control Rolling), with the inclusion of the accelerated cooling process after controlled rolling. There are various gains in terms of quality and productivity associated to the application of such technology. However, the flatness control for API steel becomes crucial because large thermal stresses may be generated due to thermal heterogeneity during the fast cooling when the austenite phase decomposes mostly into ferrite and bainite. In literature, there is lack of knowledge regarding a full understanding of the relation among cooling conditions and plate flatness. Therefore, this work has focused on the effect of the cooling strategy for API steels, aiming at optimizing flatness and keeping the mechanical properties within the specified ranges. The starting point was dilatometer simulation, where cooling conditions such as start cooling temperature, SCT, finish rolling temperature, FRT, and cooling rate, CR, were changed in order to evaluate their effect on microstructure. Those laboratory conditions supposed to give the best results were transposed to industrial scale, so as to produce experimental lots of plates with five different cooling strategies. It was shown the possibility to find a cooling profile that guarantees the balance between mechanical properties and flatness requirements. The influence of cooling strategy on flatness was explained by the varied heat transfer regimes occurring from hot steel surface to the ambient

Oct 1, 2019

By Brajendra Mishra, Mark L. Strauss, Gerard P. Martins

Nearly the entire worldwide production of europium is recovered, as a minor constituent, from mining bastnäsite, monazite ore, or ion absorbing clays. However, this research indicates a process to recycle europium from waste lamp phosphors as a strategy meet the demand for europium. In this process, waste fluorescent lamp powder is retorted, sieved, leached, and precipitated to produce a mixed europium/yttrium rare earth oxide (REO). Europium is separated from yttrium by selectively reducing Eu(III) to Eu(II) using zinc powder and precipitating europium (II) sulfate from solution using sulfuric acid. Screening experiments were conducted observe the effect of pulp density, precipitation time, entrance pH, and stoichiometric ratio sulfate upon the grade and recovery of europium (II) sulfate. The best conditions to maximize grade and recovery of europium (II) sulfate were a 1 h precipitation time, 10 the stoichiometric ratio of sulfate, 100 g/L mixed REO, and the entrance pH equal to 3. The maximum grade of europium sulfate was 95.93%, and the maximum recovery was 73.32%.

Mar 1, 2018

By Sami Kara, Marsel Nabium

As a mining project is developed from conceptual to production phases, there exists a variety of uncertainties and difficulties that affect the operation’s designs and economic values. A notable design parameter to be taken into account is the factor of dilution. Dilution is the waste material not separated from the ore in the stages of mining and is sent to the processing plant. It is defined at the ratio of tonnage waste mined and sent for processing over the combined ore and waste tonnage milled. Dilution reduction is one of the areas that offer metal mines an opportunity to increase revenue and reduce costs, resulting in enhanced profits. Effective dilution control programs require interaction on a multidisciplinary level. This paper outlines recent initiatives undertaken at Polysmetal Silver Magadam Mine to reduce dilution and increase revenue. This paper provides an overview of the solution applied in underground Silver mine in Russia. The paper reviews the dilution problem throughout the entire mining process, and provides a rational approach to underground mine Blast design in order to minimize dilution. The mining companies put a lot of effort into extracting lower grade while minimizing cost. The dilution control assists with achieving this goal. In Polymetal Silver Magadam Mine we succeeded to control more than 20 blasts by keeping almost the same grade measured in the face. The results indicated that using the adequate blasting timing design can help to separate the ore from the adjacent waste in drift blasting with different ore body configuration.

Forward-Looking Statements Information set forth in this presentation may involve forward-looking statements under applicable securities laws. Forward looking statements are statements that relate to future, not past, events. In this context, forward-looking statements often address expected future business and financial performance, and often contain words such as "anticipate", "believe", "plan", "estimate", "expect", and "intend", statements that an action or event "may", "might", "could", "should", or "will" be taken or occur, or other similar expressions. Forward-looking statements or information relate to, among other things expected iron ore demand, timing for a production decision, expected share price drivers, potential railway options, timing, grade and quantity of potential resource estimates, employment and economic benefits, taxation estimates and timing of key project milestones. By their nature, forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause our actual results, performance or achievements, or other future events, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such factors include, among others, the following risks: the risks associated with the need for additional financing; operational risks associated with exploration; fluctuations in commodity prices; title matters; environmental liability claims and insurance; reliance on key personnel and other risks and uncertainties discussed in the management discussion and analysis section of our interim and most recent annual financial statement or other reports and filings with the TSX Venture Exchange and applicable Canadian securities regulations. Forward-looking statements are made based on management's beliefs, estimates and opinions on the date that statements are made and the Company undertakes no obligation to update forward-looking statements if these beliefs, estimates and opinions or other circumstances should change, except as required by law. Investors are cautioned against attributing undue certainty to forward-looking statements. NI 43-101 Qualified Person Alderon?s exploration work on the Kami Project is supervised by Edward Lyons, P.Geo., the Chief Geologist for Alderon and a Qualified Person as defined byNational Instrument 43-101. Mr. Lyons has reviewed and is responsible for the technical information contained in this presentation. Mr. Lyons is a member in good standing of the Association of Professional Engineers and Geoscientists of British Columbia (APEGBC) and the Professional Engineers & Geoscientists Newfoundland & Labrador (PEGNL) as a registered Professional Geoscientist (P.Geo.).

May 1, 2011

By C. H. Mathewson, A. U. Seybolt

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrellce of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below. Conditions of Equilibrium between a Metal and Dissolved Oxide at Different Temperatures and Pressures The general conditions of equilibrium in any system are conveniently summarized in a projection of the triple curves of the P, T, X space

Jan 1, 1935

By D C. Franklin, C T. Farrelly

The future of human exploration in space is intimately bound to the future of mining and energy production on Earth. By 2025, one or more manned bases will probably exist on the Moon, exploring the lunar landscape and geology, and acting as a learning platform, and possibly a resource platform, for expeditions to Mars and beyond. Unless the mining and space industries take an active and cooperative interest in the technologies required to exploit minerals and fuels in and from hostile environments, the necessary advances to support permanent extraterrestrial exploration will not be ready in time. With the notable exception of using lunar Helium-3 as a fusion power fuel, no other reason has been identified for the mining industry to take any direct interest in the exploitation of extraterrestrial resources for the benefit of its customers on Earth. Ample reasons exist, however, for the industry to take a direct interest in supporting technological development of the extraterrestrial resources necessary to support the economical exploration of space. The mining industry has critical experience in the development and application of technologies for the discovery, extraction and processing of natural resources; experience that the space industry will need to create a viable permanent presence in space. The industry also understands the end to end process of resource development and utilisation. On the other hand, the space industry can directly benefit the mining sector by helping mature and advance the extractive and processing technologies needed to economically and sustainably develop resources in hostile terrestrial environments, such as those available in low concentrations, at extreme depth and/or inconvenient geographic locations. We propose that strategic partnerships be created between the mining, space and allied industries and research organisations. Such partnerships would develop a joint capability for mutual benefit, targeting the most significant advances in the least time. The space industry will learn how to exploit essential resources off-planet, and the mining industry will gain access to technologies to help extend their activities on earth.

Jan 1, 2008

By Northcote GG

There are many underground mines with shaft or decline access with limited production capacity or where the mine may become uneconomical as trucking costs escalate with increasing depth of the decline. In such cases a need may exist for a shaft hoisting system which can be constructed more quickly and more economically than a shaft sunk by conventional methods. Relatively cheap small diameter shafts can be constructed by raise boring. This paper describes a simple hoisting system which has been designed to take advantage of the benefits of raise boring. The system uses twin bored raises with a double drum winder hoisting a skip in each hole. The design concept is based on 1. accepting that the raises cannot be truly straight or vertical, 2. using the raise to guide the conveyance, and 3. minimising operating, maintenance, and capital costs. The hoisting system requires a certain degree of accuracy in the alignment of the twin raises. A survey of raise boring practice showed that the required accuracy could probably be achieved with conventional techniques. However it was thought it would be necessary to survey the pilot hole during drilling and to be able to correct the hole if deviation became

Jan 1, 1978

By James Norman

DIATOMACEOUS earth occurs in deposits widely distributed throughout the nation. The chief producing areas are in the Western States, where many high-grade deposits are known. Eastern deposits of diatomite are unsatisfactory for many purposes either because of impurity or because of the extremely fine particle size. Eastern users of diatomite, on the whole, must pay for transportation of the material from the west coast. The freight rate is necessarily high because of the great bulk of the diatomite. A satisfactory process of purifying the diatomaceous earths of Maryland and Virginia, which are unsuited for wide use only because of impurities, should be of value to eastern users. In the past, benefication of diatomite by wet processes has been limited to classification or sedimentation for the removal of sand from diatoms. Calcination with salt is used to produce a white diatomite when iron is present in the impurities, and small amounts of clay are rendered inactive in the process. No treatment has been developed whereby a large proportion of clay can be removed from a low-grade diatomaceous earth to give a diatomite of very high purity. In August 1937 the Federal Bureau of Mines, in cooperation with Dr. R. C. Williams, of Baltimore, undertook the problem of purifying low-grade Maryland diatomite by froth flotation. Work was done at the Eastern Experiment Station, College Park. Unless otherwise stated, the crude diatomite used was from the Patuxent River deposits near Dunkirk. This material, consisting of roughly one-third each of clay, quartz sand and diatoms, was representative of the usual low-grade marine diatomite found in the Coastal Plain Miocene beds of Maryland and Virginia and sporadically in other Atlantic coast states. As received, it contained 50 to 60 per cent moisture and probably had been wet since its formation.

Jan 1, 1940

By A. U. Seybolt, C. H. Mathewson

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrellce of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below. Conditions of Equilibrium between a Metal and Dissolved Oxide at Different Temperatures and Pressures The general conditions of equilibrium in any system are conveniently summarized in a projection of the triple curves of the P, T, X space

Jan 1, 1935

By Muller M, Ashley PM

Massive sulphide ZnPbCuAg deposits in the Halls Peak district of northeastern NSW are of the submarine volcanogenic type. They occur as a number of small lenses enclosed in shale and epiclastic rocks, in association with felsic volcanics of early Permian age. The deposits crop out in steep terrain near the eastern edge of the New England plateau. Local relief of 700 m and slopes up to 50¦, coupled with an average annual rainfall of about 1000 mm has led to local severe landsliding in previously mined areas. Mining from the 1890's to the 1960's has also resulted in unconstrained drainage of heavy metal-bearing acid waters and physical dispersion of finer grained metalliferous sediments into the Chandler River. Waters emanating from the main landslide area, from underground workings and draining scattered unconfined stockpiles of massive sulphide ore have pH values of 3 to 4 and contain elevated contents of Zn, Cu, Pb, Cd and Fe. Chemical mobility of heavy metals into streams occurs under low pH conditions with Zn exhibiting the greatest dispersion. Increasing pH conditions downstream cause precipitation of Fe phases and coprecipitation of heavy metals. Physical dispersion of secondary metal-bearing minerals into the surrounding creeks results in wt% levels of Cu, Pb and Zn in the stream sediments thereby exceeding the regional background values by one to three orders of magnitude. Areas disturbed by mining are characterised by lack of vegetation, biomagnification of heavy metals into algae and lower plants, and partial recolonisation by metal-tolerant grass species (Snow Grass, Poa sieberana; Blady Grass, Lomandra longifolia). Rehabilitation measures will have to include landslide stabilisation, impervious sealing or removal of sulphidic materials, import of topsoil and revegetation by metal-tolerant, slow-growing native grass and shrub species.

Jan 1, 1995

By J Pan, B-J Shi, X-B Li

The granulation behavior of specularite fines which possess poor ballability was studied with limonite fines as a function of nuclei particles and adhering fines. The results show that the permeability of granules deteriorated as the ratio of specularite fines increased in the mixture, and the optimal granulation moisture content also decreased. The granulation kinetics results demonstrate that the adhering load of specularite fines increases rapidly within three minutes and then levels off. With increasing specularite fines ratio, the adhering speed is accelerated but the granulation duration needs to be longer to reach adhering balance. The microstructure of granule quasi-particles indicates that the fine limonite particles act as binders to bond together the specularite particles which are dispersed in the adhering layers. This can improve the adhering strength of the granules. Hence, the granulation behaviour of specularite fines can be improved by blending them with fine limonite ores which have high adhering capabilities.CITATION:Zhu, D-Q, Li, X-B, Pan, J and Shi, B-J, 2015. Granulation behaviour of specularite fines in ferrous sinter mixtures, in Proceedings Iron Ore 2015, pp 91–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By Ruiling DU, Xiao YUAN, Keng Wu, Daan XU, Changyao CHAO

To utilize low grade coals to produce high quality semi-coke which can be used in blast furnaces, the pyrolysis of low grade coals was studied in this paper. According to the characteristics of coal pyrolysis process, the temperature range was divided into three parts. The interfacial chemical reaction model, random pore model and the internal diffusion model with the shrinking volume of resultant were established to describe the different ranges of pyrolysis process respectively. The results showed that the experimental data was fitted well, and all the correlation coefficients (r2) exceeded 0.97. Finally, the kinetic parameters for each temperature range have been calculated, which laid a necessary foundation for the simulation and expanded production.

Jan 1, 2016

By B Hooper

Deep cuts in CO2 emissions will be required to stabilise and, in the long term, decrease CO2 concentrations in the atmosphere. Technologies for capturing CO2 from major stationary sources (power stations, industrial plants, etc) and storing that CO2 for long periods of time is one of few near term options for decreasing CO2 emissions. This transition to low carbon intensity energy and possibly the hydrogen economy through renewables and in the long-term technological developments such as artificial photosynthesis.Capture of CO2 from post combustion emissions can be done using a range of technologies though costs are currently high and dependent on the concentration of CO2 in the emissions. Techniques include solvents, pressure swing adsorption and the use of membranes. Options for decreasing capture costs by increasing the concentration of CO2 in the emission stream include the use of oxyfuels (in pulverized fuel types boilers) and by moving to integrated gasification combined cycle (IGCC) operations either simply for power generation or for poly-generation opportunities. Once the CO2 has been captured it can be stored using a variety of methods. Storage in the ocean has been suggested but is considered an unlikely option because of environmental uncertainties and political opposition. Mineral storage is a niche opportunity. The greatest potential lies in geological storage of CO2 and this option is commanding increased attention from the Australian and international community.In Australia, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) is an important new initiative that will support energy companies and energy intensive industries in meeting challenges posed by greenhouse gas issues and assist them in their efforts to reduce their emissions profile.The progress of geo-sequestration and the challenges in the capture and separation of CO2 in the process industries are discussed.

Jan 1, 2004

By Reid T. W

This paper describes the results of investigations into the relationship between specific gravity and chemical composition in the Cockatoo Island orebody, In the early investigations the samples were classified into groups according to porosity. This resulted in high, medium and low porosity groups, the latter being further subdivided into ore and waste. Whole number tonnage factors were assigned to each group. In the later investigations the reciprocals of bulk specific gravity and true specific gravity were ex- pressed as linear combinations of iron, silica and alumina using stepwise regression. The efficiency of the models as predictors was tested by dividing the data into two sets; one of which was used to calculate the regression equation and the other to test the efficiency of the equation as

Jan 1, 1976