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By L. Echeverri

Research studies have shown that the flow within feedwells displays a vortical structure and high velocities at the locations where standard tangential inlets force its way into the feedwell swirling flow, producing high local shear rates and flow non-uniformities. These hydraulic deficiencies can be attributed to the discrete feeding through a few entrances, usually one or no more than a few tangential feedpipes, which practically project jets into the vortex within the feedwell. The main consequences are unequal flocculation with aggregates subjected to different amounts of shear and a non-uniform discharge from the feedwell. This paper presents results on the application of CFD and small-scale models to develop a new design that overcomes these problems by using an involute shaped inlet that converges around the feedwell. The result is a new feedwell with enhanced hydraulics that perfectly couples with the FLSmidth E-Duc® Feed Dilution system by protecting the flocculated aggregates that have been carefully produced upstream, and that favors uniform sedimentation conditions within the thickener thanks to a uniform discharge, while maintaining a practical and trouble-free geometry with excellent turndown.

Jan 1, 2012

By G. L. Oldright, F. S. Wartman

"In the process of smelting copper ores and secondaries in the reverberatory furnace to produce a copper matte and a slag low enough in copper content to be discarded on the dump, it is essential to the best functioning of the process that most of the iron in the material charged into the furnace be at the end in the form of sulphide in the matte or ferrous oxide in the slag. Ferric oxide and magnetite present in the charged material should be reduced to ferrous sulphide or oxide. Ferric oxide offers no difficulty in reduction, at least to the magnetite stage, because it reacts very readily with sulphides at quite low temperatures. Magnetite is less reactive and consequently more resistant to slagging, so that the furnace man must take advantage of all factors favoring its reduction in order to prevent accumulations in the furnace.In order to determine these factors more definitely, the Bureau of Mines in cooperation with the Department of Metallurgy, University of Arizona, has undertaken at the Southwest Experiment Station an investigation of the effect of various factors upon the rate of reduction of magnetite by ferrous sulphide. A previous paper's reported the nature of the reactions taking place and the effect of various physical factors when only pure sulphide and oxide were present. Since in the actual smelting operation, many other substances are also present, it seemed desirable to make a study of the effect of their presence upon the rate of reduction of magnetite by ferrous sulphide. Such a study has been made; the work done and the results obtained are described herewith.As will be shown later, it has been found that of the substances usually present in the smelting charge, silica and magnesia accelerate, whereas lime, alumina, and cuprous sulphide hinder the reduction of magnetite by ferrous sulphide.No report of a previous laboratory investigation of this subject has been found. Almost all furnace operators have made at one time or another at least qualitative ccmparisons of the effect of various changes in operating oonditions upon the behavior of magnetite in the furnace, but the conclusions derived from the experiments have never been published."

Mar 1, 1931

By B. J. Moore

This publication contains 14,242 analyses of gas samples from oil and gas wells and natural gas pipelines in 40 States and 24 foreign countries. These gas samples were collected in the period 1917-85 as part of the Bureau of Mines survey for helium occurrences. The gas analyses contained herein were made by several methods over the period covered. Analytical work on samples collected early in the period was done on the Orsat apparatus. The one-cut apparatus and four-cut fractional distillation equipment were added later. A mass spectrometer was acquired in 1949 and used for all gas analyses made after that time. From 1917 to 1978, helium analyses were made on special helium analytical equipment designed and built by the Bureau of Mines Helium Operations Laboratory. In 1978, this apparatus was replaced in the quantitative helium analysis work by a gas chromatograph.

Jan 1, 1987

By Claudio Pereira Diogo

Bobinas de aço laminadas a frio galvanizadas com recobrimento do cromo foram empregadas para a produção de telhas e calhas d’água. Entretanto, o fabricante destes produtos teve problemas com as superfícies obtidas, que mostraram sinais de marcas de deformação/estiramento. O problema é que, na aplicação desejada, uma aparência superficial que não seja brilhante e lisa é muito indesejável. Este trabalho foi feito a fim de descrever as condições que levaram o material para se comportar como visto pelo usuário (fabricante de telhados e calhas de chuva) com base em sua aparência e comportamento mecânico. Foram empregadas observações em microscópio estéreo e curvas tensão-deformação, obtidas a partir de ensaios de tração. Com base nos resultados, são apresentadas algumas opções para minimizar a ocorrência de marcas citadas durante a utilização do que as bobinas.

Aug 16, 2017

By Qingsheng Liu

A new method of recycling aluminum dross for preparation Al-Si-Ti alloy was studied in this paper. This was carried out in two processes. first the aluminum doss was pretreated by leaching and calcining process, the fine purity and phase of the intermediate oxide powder up to electrolysis demands, then, could be obtained when aluminum dross after washing have been leached for 2h at 100? in 20% hydrochloric acid and calcined for 2h at 1200?, which was treated by cryoite-based molten salt electrolysis. Finally, the Al-Si-Ti alloy was successfully obtained through electrochemical co-deposition in the cathode shows a typical as-cast microstructure. This new recycling method can produce high quality alloy and may bring remarkable economic and social benefits.

Jan 1, 2010

By Ata Akcil, Z. B. Karshigina, Ye. G. Bochevskaya, Z. S. Abisheva

"Phosphorus slag is the most heavy-tonnage waste of yellow phosphorus production, which is stored in the dump fields for many years creating ecological problems in the regions. Despite of the actions taken to utilize the slags, most of them remain in the slag disposal area. One of the relevant and priority directions is rare-earth metals production (REMs), presence of which in the phosphorus slags allows considering the latter as an acceptable raw material source. Phosphorus slags contain about 30–40 wt% of silicon dioxide, therefore they can serve as a source of production of precipitated silicon dioxide highly required in different industries.The purpose of this work is the most complete REMs recovery in the solution while leaching and subsequent processing of siliceous cake. The work shows results of researches on establishment of the chemical and phase compositions of phosphorus slags, determination of the forms of presence therein of REMs compounds, processes of phosphorus slag leaching by nitric acid and processing of produced siliceous cake by NaOH solution.Based on the data of the instrumental and chemical methods of phosphorus slag analysis, it was established that it consists of pseudowollastonite a-CaSiO3 for 90–92%. It was found out that REMs are present in it in the form of carbonate apatite Ca10(PO4)6CO3 or rare earth apatite, and La2S3 compound inclusions.Optimum parameters of phosphorus slag leaching process were selected: HNO3 concentration 7- 7.5 mol/L; L/S ratio = 2.6–3 mL/g; temperature – 50–80o?; duration – 1 h; pulp stirring – 500 rpm. Recovery of SREMs, CaO, Al2O3 and Fe2O3 into the solution were achieved at 98.0, 99.1, 99.0 and 18.8%, respectively. Presence of 10 elements of the rare earths group in the phosphorus slag was established. It was found out that recovery of almost all REMs is within ~92–99%, except for Sc and Lu – ~39% and ~28%, respectively.For the purpose of optimization of siliceous cake leaching by NaOH solution, influence of some physical and chemical parameters was studied: N?O? concentration, L/S ratio, temperature, and duration. Results of the experimental data will serve as a basis for development of the technology of complex processing of the technological waste of phosphorus industry with production of REMs concentrate and precipitated silicon dioxide."

Jan 1, 2016

By David Bassanelli Sampaio

Com a crescente demanda por sistemas distribuídos e multiplataformas, houve uma larga proliferação de métodos, linguagens e tecnologias com o objetivo de atender aos mais diversos requisitos desse ambiente. Com isso, a TI de corporações que possuem desenvolvimento interno de aplicações enfrentam um grande desafio de gerir conhecimento dos profissionais mais experientes e integrar novos profissionais de forma a garantir a qualidade e agilidade na tratativa de incidentes, bem como a capacidade de evolução e criação de novas soluções. Neste trabalho, apresentaremos as diretrizes, tecnologias e processos desenvolvidos na Usiminas, consolidados em uma arquitetura. Esta arquitetura propiciou, entre outros, a estabilidade e continuidade dos sistemas existentes, a padronização da experiência final do usuário, a agilidade na construção das soluções Java, evoluindo a qualidade dos sistemas mantidos pela TI, com resultados efetivos.

Oct 30, 2017

By K. E. Brown, J. P. Brill, A. R. Hagedorn, T. C. Doerr

A recent correlation for multiphase vertical flow by Hagedorn and Brown1,7 has been used to examine the effect of numerous variables such as pipe size, gas-liquid ratio, liquid flow rate, liquid viscosity, liquid surface tension, oil API gravity, water cut, etc., on flowing pressure gradients. Most previous correlations were derived by using a form of the general energy equation which assumed negligible changes in kinetic energy. Under certain flow conditions this can lead to serious errors in predicting pressure traverses. Examples of traverses calculated both with and without the kinetic energy term are included here. The Chew and Connully correlation for calculating changes in viscosity with changing pressure and temperature has been extended so that the effect of a changing viscosity with depth on pressure gradients can also be predicted. Examples illustrating the effect of tubing size show the importance of this correlation in determining pipe sizes for initial well completions. Limitations on production rates in small pipe sizes from excessive friction losses can be predicted with greater accuracy. The combined use of a vertical-flow correlation with a horizontal-flow correlation provides a method for determining the maximum flow rate possible from both flowing and gas-lift wells. Examples are included to illustrate application of the combined use of vertical and horizontal-flow correlations in optimizing production rates and minimizing excessive costs from over injection of gas in gas-lift wells. INTRODUCTION The problems of multiphase vertical and horizontal flow are immediately encountered in any producing well. Fig. 1' shows three stages of production: flow in porous medium, vertical flow and horizontal flow. All three stages affect the production rate from a well. If we are confronted with a particular well and consider only the variables involved in the vertical and horizontal stages of Fig. 1, we should be capable of calculating the flowing bottom-hole pressure necessary to produce a particular flow rate. A change in any of the variables results in a new solution to the problem. Recent approaches in developing horizontal and vertical-flow correlations have improved to the extent that the solution can now be obtained with more confidence than previously. VERTICAL AND HORIZONTAL FLOW CORRELATIONS Since Poettmann and Carpenter's' original work in multiphase vertical flow, there have been many additional vertical-flow correlations developed which have greatly improved the accuracy of pressure-loss calculations. These

Jan 1, 1967

By Gislan William Guimarães

Neste trabalho avaliou-se o efeito de diferentes ciclos térmicos na microestrutura e propriedades mecânicas de um aço Dual Phase revestido por imersão a quente, da classe de resistência de 800 MPa, a partir de simulações em escala piloto no equipamento HDPS (Hot Dip Process Simulator), ensaios dilatométricos, tração à temperatura ambiente e flangeamento. Nas simulações de recozimento contínuo foram experimentadas duas temperaturas de encharque no recozimento intercrítico (740°C e 780°C) e três temperaturas de patamar isotérmico no resfriamento rápido (610°C, 560°C e 510°C). A caracterização microestrutural evidenciou que a temperatura de encharque de 740°C não foi suficiente para dissolução completa dos carbonetos formados na laminação a quente, resultando em frações reduzidas de segundo constituinte. Com isso, o limite de resistência mínimo de 800 MPa não foi alcançado. Além disso, os resultados de ductilidade e flangeamento se mostraram aquém dos obtidos nas simulações com encharque a 780°C. Nas simulações com temperatura de encharque a 780°C e isotérmicas de 510°C e 560°C no resfriamento rápido foi atendido o limite de resistência mínimo, com capacidade de expansão de furo ligeiramente superior à obtida nas simulações com encharque a 740°C.

Aug 16, 2017

By Samuel M. Shallcross

The principal function of the Bell limestone mine, of the American Lime & Stone Co., at Bellefonte, Pa., is to supply raw material to the company's modern rotary kiln plant at Bellefonte. Because mining costs are naturally higher than many open quarries with more favorably lying strata, it cannot compete, except to a limited extent, in the markets for road material and fluxing stone. In the broad sense, mining does have an advantage over the average open quarry when the end products are designed for and controlled by process and final inspection for the exacting demands of the industrial and chemical markets. Approximately 80 per cent of the output of the Bell mine is sold in the industrial and chemical markets. And as higher standards are set each year for construction and agricultural work, the remainder of the mine output goes to these two classes. Mining produces more fines than open quarries, and these fines are difficult to market; on the other hand, owing to absence of contaminating clay and impure rock, a greater percentage of the output of a mine is marketable. Because of the great production of fines, rotary kilns for lime burning are necessary when the stone must be mined. In 1921 the American Lime & Stone Co. operated 19 quarries and 72 lime shaft kilns spread over an area of 40 miles between Bellefonte and Altoona, Pa. At that time the lime-production capacity of the 72 kilns amounted to approximately 700 tons per day. After 15 years the company operates three rotary kilns and six shaft kilns, with a combined output of approximately 500 tons of lime per day, concentrated in its single Bellefonte plant (Fig. 1). Its only stone-producing plants are now the limestone mine at Bellefonte and a construction-stone open quarry at Union Furnace, near Tyrone, Pennsylvania. Since the middle of 1922, the management of the American Lime R. Stone Co. has been under the direction and ownership of the Warner Company, of Philadelphia. To the Warner Company's experience, gained through successful operation of lime plants in eastern Pennsylvania for many years, and the successful solution of material-handling problems

Jan 1, 1937

In 1990, the Bureau of Mines (BOM) conducted a mineral investigation of the mines and prospects in the East Mojave National Scenic Area (EMNSA), San Bernardino County, California During field work, BOM identified 701 mines and prospects in EMNSA for which the geology, mineral resources, and mining history were compiled and summarized. Analytical results for 1,188 rock samples collected are tabulated. Total value of identified resources in EMNSA is $5.0 billion. Twenty-four mines and prospects were deemed profitable under current economic conditions. Development could generate considerable economic benefits to San Bernardino County. Potential economic benefits from mining the deposits were evaluated under the following access restrictions for EMNSA: 1) full access, 2) HR 3460, and 3) S 11/HR 780. Under the full access scenario, cumulative mine revenues are $3.0 billion, cumulative personal earnings at mines and supporting industries are $0.94 billion, and annual jobs at mines and supporting industries are 2,379. Under HR 3460, mine revenues, personal earnings, and annual jobs are $2.9 billion, $0.88 billion, and 2,165, respectively. Under S 11/HR 780, mine revenues, personal earnings, and annual jobs are $1.0 billion, $0.32 billion, and 936, respectively.

Jan 1, 1990

The key aspects of process metallurgy that distinguish platinum group metal (PGM) concentrate smelting from that of other base metal sulphide concentrates are presented. These differences include considerably higher input chrome and magnesia contents that directly raise the slag liquidus temperature and have the potential to increase accumulations of refractory spinels. Most importantly, the higher processing temperature required for PGM smelting and the resulting very high matte superheat lead to considerably more onerous smelting conditions than those typical of other smelting operations. This has presented challenges to furnace design and integrity, especially when coupled with the progressive intensification of smelting, involving doubling, and then redoubling, of furnace power inputs over the past 20 years. These power increases have been enabled by increasingly more advanced furnace cooling and structural technologies. Key technologies include strong constant-force spring-loaded bindings acting in three dimensions to minimize infiltration of superheated matte into brick joints, and robust well-cooled tapholes for reliably tapping the superheated matte. The result has been substantially improved productivity, and reduced smelting capital cost outlay per unit of production. A significant challenge, which was not anticipated, presented itself in the form of insidious corrosion of the furnace lining, and especially high-intensity copper cooling elements. Investigation of corrosion in related industries eventually identified chloride-accelerated sulphidation', and this term has been retained as it generically describes the most pertinent aspects of the accelerated low-temperature wear of copper coolers observed in PGM smelting. In addition to discussing the corrosion mechanism, this paper describes a number of solutions that were developed jointly by Anglo American Platinum and Hatch to address the copper corrosion problem. First, new monitoring technologies allowed furnaces to be operated more safely for a longer period of time. Second, a system for replacing corroded coolers from outside the furnace during a fast 'hot' shutdown minimized the impact on furnace operating factor and hearth life. Finally, a corrosion-resistant graphite-protected cooler design significantly improved furnace campaign life, and heralds a more lasting solution to cooler corrosion in PGM furnaces.

Jan 1, 2013

The association of deep well turbine type pumps with metal mining is by no means a new one, though undoubtedly each application has certain features of interest, conformable with attendant circumstances. Although all conditions pertaining to a particular operation in one mine are rarely, if ever, duplicated in another mine, it is felt that some aspects will be parallel, or in various ways comparable.Therefore the following descriptions of an installation of a deep well turbine pump as part of dewatering plant in connection with shaft sinking may be of general interest to metal mine operators.The Man and Supply shaft at Mount Isa Mines is designed as shown in plan by Fig. 1. It is the main entrance and service shaft for the entire property and hence is in constant use. Arrangements for sinking must be such as to cause little or no impediment to routinehoisting work. Also, being the main shaft, it has been essential to deepen it in step with successive level developments.During the period of operations at Mount Isa only a limited time has been available to complete succeeding levels down to the present No. 7 haulage level (895 ft.), and sinking operations in soft, broken, leached, and heavy water-bearing country have presented many features militating against reasonable speed and cost. Outstanding among these difficulties has been the large volume of water contained in the pervious brecciated country.

Jan 1, 1939

By H. S. Price

This report discusses the development of a mathematical model that describes the flow of methane only and methane and water in a coal bed during mining operations. Because of the complex geometry, boundary conditions and fluid properties, the model is based on a numerical solution to the equations describing flow. The goals for the development of this model and requirements to which it complies are for the most part expressly stated in Request for Proposal No. 50110752. In addition to the capabilities specified under the scope of work the model can handle an anisotropic porous medium and a source term has been added which will simulate, somewhat, the effects of desorption. This term will be pressure dependent. The effect of time on such a term is only taken care of in the change of pressure with time. This source term will have the dimensions of Mcf/day/Mcf pore volume. It will be a part of the input data to be supplied by the user and will be entered as a table of rates versus pressure. These models consider the fracture system as the main porosity. All computed results pertain to the fractures. The source term mentioned above represents the flow from the matrix porosity into the fracture. Such flow should be small compared with the flow between fractures since these models handle only one porosity structure system.

Jan 1, 2012

"Mineral separation by exploiting the differences in mineral or metal specific gravities (sg) has been used since antiquity. In the modern era, this is most commonly seen in the recovery of gold by the use of centrifugal concentrators and the separation of coal (low sg) from waste rock (high sg) using heavy media cyclones and jigs. Other metals, notably oxides of tin and tungsten, are successfully recovered using some combination of jigs, spirals and shaking tables. However, many conventional gravity separation systems are limited to fairly coarse (>1 mm) to medium (>100 micron) particle separations due to the limitations of the gravitational separation forces in conventional equipment.Many of the high specific gravity minerals of interest are friable (e.g. cassiterite, wolframite, etc.) and excessive fines are generated in the grinding/comminution circuits which cannot be recovered with conventional equipment and may be lost directly to the tailings stream. Recent developments in centrifugal gravity separation equipment specifically designed for fine or ultra-fine particle separation and recovery have resulted in heavy mineral particle recoveries as fine as 10-20 microns. Ongoing research work has also identified the benefit of closed-circuit, multi-stage gravity recovery circuits using some combination of centrifugal concentrators and conventional equipment (tables, spirals, flotation, etc.) which can substantially increase overall plant recovery and final concentrate grade.This paper will provide details of the evolution of non-fluidized bed gravity concentrators for high sg mineral recoveries, correlate laboratory scale development work with plant results to confirm scale-up, and show how recent flowsheet developments have contributed to significantly improved plant performance.IntroductionGravity concentration is one of the oldest and most cost effective metal and/or mineral recovery systems, ranging from the classic hand panning of alluvial gold, through to the large scale production of a wide range of metals and minerals, including gold, silver, PGMs, black sands, coal and iron oxides. Conventional gravity recovery systems, comprised of some combination of sluices, spirals, jigs and shaking tables have limited application in fine particle (i.e. <100 microns) recovery, or where there are limited differences in particle specific gravities (sg), e.g. the separation of high sg, high value metal oxides (e.g. those of tin, tantalum or tungsten), from medium sg, lower value metal sulfides such as pyrite and pyrrhotite. These unit operations tend to have limited capacity, and while double and triple turn spirals and multi-deck tables have been developed, extensive floor space is often required in order to process the tonnages incorporated in the modern mineral processing plant."

Jan 1, 2017

By A. C. Hitchins, C. N. Orssich

The Eagle zone is a gold-bearing, sheeted, quartz vein porphyry deposit hosted by the Cretaceous Dublin Gulch biotite granodiorite stock, located in central Yukon, 50 km north of Mayo. The deposit occurs at the western end of the stock and has been drill tested over a 1000 m by 500 m area, to a depth of 150m. Mineralization consists of 1 cm to 2 Cm wide, parallel, grey and white quartz veins with accessory gold, arsenopyrite, pyrite, pyrrhotite, chalcopyrite, native bismuth, bismuthinite, and scheelite. Vein densities range from two to fifteen veins per metre and average approximately five per metre. The majority of the veins have potassic and or phyllic alteration envelopes. Alteration of the granodiorite becomes pervasive as vein densities increase. Mineralization outside of the Eagle zone, but spatially related to the Dublin Gulch stock, includes: (i) scheelite bearing sheeted quartz vein zones within the east-central portion of the stock; (ii) a swarm of gold-bearing quartz-sulphide veins up to a metre wide in a zone along the northern contact of the stock and extending 7 km further west; (iii) the Mar scheelite skarn located on the south side of the stock; and (iv) cassiterite-bearing breccias located 2 km north of the stock. A geological potential resource of 64.5 Mt tonnes at a grade of 1.03 g/t Au has been estimated for the Eagle zone from widely spaced core and reverse circulation drill holes. Mineralization is open at depth, on strike to the west and beneath the hornfels to the north.

Jan 1, 1995

Total U.S. mineral production reached an estimated $17.8 billion for 1960, 4 pct above 1959 and second only to the record high of $18.1 billion established in 1957. As a group, metals achieved a rise from $1.6 billion in 1959 to $2.0 billion this year, an increase of 28 pct. Similarly the value of nonmetallic production including fuels (i.e., natural gas, petroleum, natural-gas liquids, asphalt and related bitumens, carbon dioxide. anthracite. bituminous and lignite coal, peat, and helium) rose from $15.5 billion in 1959 to approximately $15.8 billion in 1960. However, this 2 pct increase in the total value of non-metallic production was due to an increase in the value of the fuels ($11.8 billion in 1959 to $12.2 billion in 1960) which offset a drop in value of the other nonmetallic minerals ($3.7 billion in 1959 to $3.6 billion in 1960).

Jan 2, 1961

Jan 1, 1969

By A. E. Tercan, D. Mamurekli

Ordinary kriging on the assumption of a gaussian error distribution and indicator kriging were used to derive the probability that a given calorific value would or would not be exceeded by coal from an area of a deposit. The two techniques led to similar probability maps despite local differences; the lack of an absolute reference makes it impossible to judge which method is better for this particular application

Jun 19, 1905

By Pedro Vargas Gálvez

El presente texto señala la metodología de selección del software de mantenimiento respecto a este mismo y a la Planta. Para ello, se detalla las condiciones que deberán considerarse en la Organización de Mantenimiento y la aplicación del Software de Mantenimiento MP2 a una empresa. Asimismo, se presenta el Plan de Implantación, los inconvenientes que se han encontrado así como los resultados obtenidos por la utilización del Software MP2.

May 25, 1998