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By H. A. Khorami, T. Wong, B. Velapatino, E. Asselin, T. Donnelly, E. Bryce, R. Dixon

A copper–nickel concentration gradient alloy was designed and fabricated through a powder metallurgy (PM) process. Copper and nickel powders were mixed with different weight ratios from 0 to 100% copper in 10% increments. Each powder mixture was poured inside a cylindrical die and compacted between two punches using a hydraulic press machine at pressures up to 70 MPa, resulting in approximately 1 mm thick layers (discs) of pressed Cu–Ni powder. These 11 Cu–Ni compacted powder layers, i.e. 0–100% Cu with 10% increments, were then compressed together with pressures up to 420 MPa to form a green part. The green part was sintered in a vacuum furnace at 1000°C for 10 hours to form a solid mass (PM part) of Cu–Ni concentration gradient alloy. In the sintering process, Cu and Ni particles fused together and formed a single piece due to diffusion of the atoms across the boundaries of the particles. The diffusion of atoms also converted the stepwise concentration change into a uniform concentration gradient. INTRODUCTION Copper has numerous applications in different industrial sectors due to its superior physical, electrical, mechanical and chemical properties such as its excellent thermal and electrical conductivity, resistance to fatigue, high ductility, and resistance to corrosion. Moreover, copper and its alloys have natural antimicrobial properties. This has opened up new applications for copper–based self–disinfecting surfaces in healthcare in an effort to mitigate healthcare–associated infections (HAIs). HAIs affect millions of patients each year, leading to significant morbidity and mortality as well as financial losses to healthcare systems (World Health Organization, 2016). HAIs spread through three main routes: (a) iatrogenic in which HAIs are a direct consequence of medical encounters and/or treatment; (b) person to person where organisms are transferred between healthcare workers, patients, and visitors; and (c) environmental where transmission occurs via contaminated surfaces and equipment (e.g. doorknobs, railings, toilets/commodes, medical carts). The use of antimicrobial copper–based materials on high touch surfaces could diminish pathogen transmission via this latter rout. This has subsequently led to the development of a variety of copper–based materials for use in healthcare settings and promoted the investigation of the antimicrobial efficacy of copper–based materials.

Jan 1, 2019

By R. S. Kalyoncu

Materials demands by the advancing process technologies, desire for higher performance and durability, and improved efficiency in combustion processes, such as applications in heat engines, heat exchanges, and batteries have added to the driving force fueling R&D efforts for the development of components with the combined characteristics of metals and non-metals. These new materials involve refined and specialized microstructures that can lead to improvements in the performance characteristics and durability new technological applications require. Fabrication and sintering methods, once believed to be sufficient, alone, have been found to be inadequate in the manufacture of such advanced components. Realization of the importance of the starting powders has led to efforts to produce materials of ultrahigh purity and ultrafine particle size with very narrow particle size distributions. Such powder characteristics are essential for the fabrication of components with high density and with the desired mechanical, electrical, or magnetic properties called for by the specific application. Novel ultrafine and ultrapure powder preparation techniques are discussed and effects of impurities on the powder characteristics, particle size and morphology, sintering behavior and properties of the finished product are elucidated.

Jan 1, 1992

By Carlos Eduardo Pinedo

A nitretação dos aços inoxidáveis tem sido objeto de diversos estudos nas últimas décadas. O objetivo primordial é promover o endurecimento superficial e com isso elevar a resistência ao desgaste, sem comprometer a resistência à corrosão. Em vista disto, a nitretação sob plasma a baixa temperatura, abaixo de 430oC, tem se mostrado um processo eficiente para inibir a precipitação de nitretos de cromo e promover o endurecimento superficial pela formação de fases expandidas pela supersaturação de nitrogênio. Este trabalho mostra a formação de ferrita expandida em um aço inoxidável ferrítico. Para isso foi utilizada o processo de nitretação sob Plasma-DC na temperatura de 400oC por 20 horas em mistura gasosa contendo 75%N2 e 25%H2. Os resultados de Difração de Raios-X mostraram que a nitretação em baixa temperatura é capaz de formar uma camada nitretada de ferrita expandida. Em Microscopia óptica observa-se uma camada homogênea com profundidade média de 32 microns de profundidade e dureza média de 1296 HV promovendo um endurecimento superficial do aço inoxidável ferrítico em mais de 5 vezes sem que ocorra a precipitação de nitretos de cromo e, com isso, preservado a resistência à corrosão.

Oct 30, 2017

By Ernst Lindemann

Steel suppliers are required to deliver sheets with particular qualities and with lightweight-potential to the automotive industry. New types of steel call for new production processes. SMS group has developed a new micro-mill-concept, the core of which is the belt caster. This was first built on an industrial scale and has been put into operation and developed together with Salzgitter Flachstahl GmbH. The robustness in industrial-scale operation could be verified. The full use of the belt casting technology, mainly related to energy efficiency and CO2 reduction, is realized with the micro-mill-concept. This is an in-line-process, casting and rolling in one line.

Aug 17, 2017

I WISH to express to the members of the Institute my sincere appreciation of the distinction which they have conferred upon me by again making me their president. It also gives me great pleasure to once more welcome the Institute to Mount Lyell.Since your last visit certain improvements in plant have been made, which I trust you will have found interesting, and which show that, though located in a remote corner of the world, we are abreast of the times.The opportunities which a recent lengthy trip to America has given me to observe the degree of interest which our local smelting practice continues to arouse in metallurgical circles make it seem appropriate that I should take advantage of your visit to lay before you some detailed information on the more practical features of pyrite smelting, particularly as carried out at Mount Lyell. There are only a few places in the world where the method is now being practised in approximate purity-only about half...

Jan 1, 1915

By E. F. Paski

Geological materials are likely the most complex and challenging substances to quantitate by ICPOES (inductively coupled plasma optical emission spectroscopy). For complex materials having widely varying compositions, spectral overlap interferences govern detection and quantitation limits attained by ICPOES based analytical methods.

Jan 1, 1993

By D. Raghavan

In recent years, the environmental issues related to the landfill shortage received considerable importance. Many polymeric solid wastes have high resistivity to chemical and biological degradation, and options are sought by which these wastes can be recycled and reused, or reduced in volume. The present study investigated the biodegradation of polyethylene by Aspergillus niger, and biodesulfurization of rubber by pure and mixed cultures of Thiobacillus thiooxidans and Thiobacillus ferrooxidans. The fungus, A. niger, was found to metabolize portions of polyethylene. Quantitative calorimetric measurements revealed that the amorphocity of the sample decreased during biodegradation. Removal of sulfur from synthetic rubber samples containing 2 to 15% sulfur, was studied in shake flask experiments and the associated oxygen consumption was studied in Warburg respirometers. The mixed bacterial cultures were more effective in the desulfurization of rubber samples than the pure cultures of T. thiooxidans and T. ferrooxidans. The data obtained in these studies may have far reaching consequence for the development of new effective processes regarding the remediation and management of discarded polymeric packaging wastes and car tire rubber materials.

Jan 1, 1993

By Drew Bazil, David Smith, Matteo Ferrucci, David Pittman

The Gateway program will provide additional rail capacity between New Jersey and Manhattan. This paper describes how a 70-foot-deep section of cut and cover tunnel was designed to directly support future high-rise towers. The tunnel will link previously completed tunnel sections under Hudson Yards to future tunnels under the Hudson River. The design aims to minimize constraints on future overbuild and future tunnels, while maximizing constructability within a small worksite. The tunnel will pass under the High Line elevated walkway, next to an active rail yard, and close to a subway tunnel. The design was developed by a tri-venture of WSP, STV and AECOM. WSP led the design of major underground works; STV designed utility relocations and the underpinning concept for the High Line; and AECOM designed temporary in-tunnel systems. Construction is expected to start in 2023.

Jun 13, 2023

By Andreza Menezes Lima

Dispersões de óxido de grafeno foram caracterizadas com respeito ao tamanho de cristalito e número de camadas, a partir do emprego das técnicas de difração de raios X, espectroscopia Raman e microscopia de força atômica. Todas as análises forneceram valores menores que dez camadas de carbono e concordantes com o reportado por outros autores. Os métodos de difração de raios X e microscopia de força atômica permitiram obter valores mais próximos, em comparação ao obtido por espectroscopia Raman.

Oct 30, 2017

By A. Aaltonen, S. Paloranta, H. Myllykangas

A property based dynamic model of flotation was built and validated for training purposes. The model is based on the work of the AMIRA P9 project. The recovery of each particle with composition and size is calculated in a given simulation step. The model takes into account machine and operational parameters such as air flowrate and froth height. The model was created using fullscale test data on Pyhlisalmi Cu-Zn-pyrite ore with flotation kinetics of multiphase particles determined. Simulation and validation shows that model can predict the dynamic behavior of the process accurately enough for training purposes.

Jan 1, 2009

By James J. Meadows, Jason D. Pampena, Emanuele G. Cauda, Lauren G. Chubb

Exposure to respirable crystalline silica (RCS) can cause serious and irreparable negative health effects, including silicosis and lung cancer. Workers in coal mines have the potential of being exposed to RCS found in dust generated by various mining processes. The silica content of respirable dust in one single mine can vary substantially over both time and location. The current monitoring approach for RCS relies on the use of traditional air sampling followed by laboratory analysis. Results generated using this approach are generally not available for several days to several weeks after sampling, and this delay prevents timely and effective intervention if needed. An alternate analytical method is needed to reduce the time required to quantify the RCS exposure of mine workers. The National Institute for Occupational Safety and Health (NIOSH) has developed a new method using commercially available portable infrared spectrometers for measuring RCS at the end of the sampling shift. This paper will describe the application of the new field-based RCS analytical process for coal mines, including the use of the new method with the existing Coal Mine Dust Personal Sampler Unit. In a case study conducted by NIOSH with a coal mine operator in West Virginia, field-based RCS analysis was completed at a mine site to evaluate the new technique. The RCS analysis results obtained by the field-based method in this case study showed sufficiently strong correlation with results obtained by the MSHA standard laboratory analysis method to allow the mine operator to use the field-based method for evaluating process improvements.

By Douglas Marcel Quatiabara Sander Libardi

O optical televiewer (OPTV) é um dispositivo de perfilagem geofísica que produz uma imagem contínua e orientada da parede do furo de sondagem. Neste trabalho, foram selecionadas perfilagens realizadas em furos de sondagem executados em duas minas que fazem parte da ‘Megaestrutura Gandarela’, localizada na porção centro-norte do Quadrilátero Ferrífero, Minas Gerais. As imagens geradas pela sonda OPTV desempenham um papel auxiliar em campanhas de exploração mineral e também na aquisição de informações geotécnicas. Os dados coletados foram retirados das filmagens realizadas a partir da sonda OPTV e do geoposicionamento oferecido pela sonda. A marcação das estruturas nas imagens de OPTV, a correção da deriva magnética e as análises cinemáticas foram realizadas nos softwares WellCad e Dips. O principal objetivo deste trabalho é efetuar a análise cinemática feita a partir de estruturas marcadas em imagens de OPTV e compará-la com a análise cinemática efetuada a partir das estruturas identificadas no mapeamento geológico estrutural nas minas. O estudo mostrou que as estruturas marcadas com OPTV reproduzem satisfatoriamente as observações do mapeamento geológico estrutural.

Oct 30, 2017

By Wayne Hilgedick

Peabody Coal Company is the nation's largest producer of coal and is headquartered in St. Louis, Missouri. In 1978 Peabody divisionalized its operations to establish more responsive and effective mine management. Peabody Coal Company's Arizona Division operates two large surface mines, the Black Mesa and Kayenta Mines. Both are located in northeastern Arizona, approximately 30 miles from Kayenta, Arizona, on the Navajo and Hopi Indian Reservations. The Black Mesa Mine produces 4 to 5 million tons of coal per year and the Kayenta Mine produces 7 to 8 million tons per year. Coal from the Black Mesa Mine is transported 274 miles by coal slurry pipeline to the Mohave Generating Plant located on the Nevada/Arizona border at Bullhead City, Arizona. This plant is jointly owned by Southern California Edison, the Los Angeles Department of Water and Power, Nevada Power Company and Salt River Project Agriculture Improvement and Power District.

Jan 1, 1983

By James R. Hein

Manganese nodules from the Cook Islands (CI) Exclusive Economic Zone (EEZ) are compositionally different from other nodule fields. CI nodules have relatively high cobalt concentrations and low nickel, copper, and manganese concentrations (e.g. Hein and Petersen, 2013). This reflects the predominantly hydrogenetic (seawater source) origin for metals in the CI nodules versus dual seawater-pore water sources for most other nodules. The concentrations of many critical and strategic metals have not been previously analyzed for CI nodules, so comparisons with other nodule fields have been limited. To address this, we analyzed a set of nodules distributed throughout the CI EEZ for a complete set of 67 elements, including all of the metals that may be of economic interest, such as the rare earth elements (REEs), yttrium, tellurium, niobium, zirconium, tungsten, titanium, and others (see selected elements in Table 1). In addition, we recalculated the tonnages of nodules and contained metals from nodule abundance areas (in square kilometers) determined by GIS ArcMap calculations based on JICA/MMAJ (2001) nodule distributions. The nodule tonnage calculated and summed from each abundance sector yields a total inferred resource estimate of 9.66 billion tonnes of nodules covering an area of 1.21 million square kilometers; using a cut-off of 6 kilograms of nodules per square meter, yields a median tonnage of 8.59 billion tonnes of nodules covering 687,647 square kilometers (Table 2).

Sep 14, 2011

By B. W. Moore

The U.S. Bureau of Mines investigated the separation of heavy rare-earth elements (REE) in an ion-exchange process. An ion-exchange column consisting of two sections, a loading section and a separation section, provides high levels of REE loading and good REE separation with an expected processing cycle of less than a month, while current ion-exchange technology requires more than 5 months. A different resin is used in each section: sulfonic resin in the loading section and iminodiacetic resin in the separation section. The separation section is further divided into two segments: the first conditioned with NH4 and the second with acid. Erbium is loaded onto both segments of the separation column as a retaining ion. Bands of mixed REB eluting between separated bands of pure REB were recycled directly to the column. Without mixed-band recycle, over 80% of the REE eluted from the column was separated into fractions with 99% purity of each element; with such recycle, the percentage of separated elements can be increased to around 90%.

Jan 1, 2010

By Glen C. Ware

The Bureau of Mines determined the factors involved in the corrosion of starting sheets used in the production of electrolytic zinc with the ultimate purpose of adapting zinc starting sheets to commercial practice . Under present practice , zinc is electrodeposited on aluminum cathodes and subsequently stripped for melting . The use of zinc instead of aluminum would eliminate the need to strip the deposit , thereby reducing the cost of handling and melting it , but zinc has not been suitable because it was too vulnerable to the corrosive attack of the electrolyte . Serious attack was found to be limited to the areas of the cathodes situated immediately above the surface of the electrolyte and to re - entrant corners . It was possible to avoid solution - level corrosion by immersing the starting sheets completely , exposing only a relatively heavy suspension member to solution - level attack . Zinc starting sheets could be made as reliable as aluminum and could be continued in residence for periods up to 39 days . Periods as long as a week were feasible under conditions similar to those found in commercial practice . A test of zirconium as a starting - sheet material showed that it promoted corrosion of the deposit to a lesser extent than aluminum and that the deposit adhered less tenaciously . These two properties lend themselves to the development of ways to strip deposits mechanically from zirconium starting sheets . Titanium was unsuitable for use as a starting - sheet material .

Jan 1, 1963

By R. Dawson Hall

LONG regarded as nearly worked out, the anthracite region still shows promise of a hundred years of life, for means are being found to get bottom, top, pillar, and other coal that earlier generations disregarded as too expensive to mine. Rock drivages and, still more, machinery are making it possible to get such coal. Mechanical methods enable the owner of thin beds to mine these with profit, and the miner recognizes that he must permit the use of machinery or the inexorable laws of economics will deny him opportunity to work. E. L. Dana, Jr., well outlines this situation, which in the past year became definitely established. Stripping also is recovering, safely and inexpensively, coal that past generations regarded as too hazardous and costly for mining.

Jan 1, 1935

By L. Ziyuan, S. Chunbao, K. Jue, H. Yang, S. Tichang

In this study, potassium ferrocyanide, a non-toxic cyanide precursor in dark and diffuse reflection environments, was applied as a reagent for the leaching of gold. The free cyanide ions were gradually released from the potassium ferrocyanide solution under the ultraviolet light. Orthogonal leaching experiments were performed in gold ore to analyse the effect of solution pH, potassium ferrocyanide dosage, and temperature in potassium ferrocyanide solution system under UV light. Response surface methodology (RSM) was applied to explore the role of potassium ferrocyanide in gold leaching, Optimised results showed that the gold recovery reached 67.74% in a high-alkaline environment at a 12.6 pH, 3.8 kg/t potassium ferrocyanide dosage, 62°C, and irradiance of 10mW/cm-2. The gold leaching kinetics was monitored by quartz crystal microbalance with dissipation (QCM-D) of potassium ferrocyanide solution. The results indicate that the gold extraction process consists of two processes: adsorption and leaching, and a rigid adsorption layer formed on the reaction surface. Furthermore, Xray photoelectron spectroscopy (XPS) analysis of the gold sensor surface after leaching reaction showed that -C≡N appears on the gold sensor surface, and the gold is oxidised to form AuCN complexes. Keywords: Gold leaching, potassium ferrocyanide, UV light, QCM-D, AuCN complexes

Jan 1, 2020

By Utley Wedge

(Cleveland :Meeting, October, 1012.) In general, the art of securing copper from sulphide ores or concentrates may be said to consist of : (1) separation, in the molten state, of copper sulphide with some iron sulphide, from the great bulk of gangue-material, followed by (2) elimination of sulphur and iron from the molten matte, by oxidation and fluxing, leaving metallic copper. The definition is made broad enough to cover the general practice, whether or not the ore or concentrate is given a preliminary roast for the removal of surplus sulphur. The above process, which I will designate as the smelting process, makes necessary the presence in the ore, or the addition thereto, of such silica, lime, and iron as may be necessary for the formation of a light and fusible slag, together with sufficient sulphur and iron for the formation of copper-matte, and also the addition to the matte of sufficient silica for the oxidation and fluxing-out of the iron. These items, together with the cost of fuel sufficient for melting the mass, constitute important items of cost in the copper-smelting process. Numerous cases where fluxing-materials are scarce or dear, or where fuel is expensive, have caused special attention to be given recently to the wet process of copper-extraction, which may be designated as consisting of forming soluble copper salts which are then washed or leached out of the ore or concentrates by dissolving in water or acid. Metallic copper may then be secured from the solution of copper salts by electrolysis; by cementation; or copper can be brought out of the solution as a * Presented also at the Joint Meeting of the Institute and Section IIIa, Metallurgy and Mining, of the Eighth International Congress or Applied Chemistry, New York, N. Y., September, 1912, and here published by mutual agreement.

Dec 1, 1912

By A. A. Blow

The productive area of the Leadville mining district immediately adjoining the city of Leadville, which, by its wonderful richness, has attracted the attention of the mining world for the past twelve years, may, with a few exceptions, he considered as divided into seven local mining centers, separated one from another by the topographical features of the country, and designated by common consent as Fryer Hill, Yankee Hill, Breece Hill, Rock Mill, Printer-Boy Hill, Iron Hill, and Carbonate Hill. Of these seven distinot mining localities, or groups of mines, the central one, Iron Hill, is the one of greatest importance and interest. It was the scene of the earliest discovery of carbonates, as far back as 1875, and since that time has always maintained its position

Jan 1, 1890