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By Du Sichen, S. Seetharaman, J. A. Bustnes

"The present study deals with the kinetic studies of reduction of some selected transition metal tungstates with hydrogen. The measurements were carried out by the isothermal thermogravimetric method. Shallow powder beds were employed in order to avoid the effects due to transport phenomena affecting the reaction rate. In this way, the chemical reaction rates could be selectively studied. The experiments were carried out in the temperature range 873 - 1173 K. From the experimental data, the activation energies were evaluated and were found to be around 88 kJ / mol in the case of both iron as well as cobalt tungstates indicating the similarities in W-O bonds in both cases. The activation energies obtained are discussed in the light of the position of the transition metal in the periodic table as well as the thermodynamic stabilities of the various tungstates.IntroductionThe tungsten containing hard metals, characterized by high density, belong to a class of two-phase metal matrix composites. While these types of materials have traditionally found their applications within the defence industry as armour-piercing projectiles, counterbalance in helicopters and military aircrafts, outer casings of hand-grenades, etc., commercial applications for this class of alloys also exist, including radiation shields, penetrators for the oil industry, turbines for turbo-jet engines and a wide range of sports related parts. A possible route to the production of these alloys is to reduce the tungstates such as FeW04, Co W04 and NiW04 using a reductant like hydrogen or carbon monoxide. In order to have a better understanding of the processes involved in the production, it is important to have a knowledge of the reduction kinetics for these tungstates. According to the knowledge of the present authors, while the reduction ofNiW04 by hydrogen gas has been investigated earlier in the present laboratorypl no systematic reduction study has been carried out previously for the tungstates of iron, cobalt."

Jan 1, 1996

By Donald P. Ziegler, James F. Klausner, Srinivas S. Garimella

"By 2015, nearly half the world's population will live in ""water stressed"" areas. Production of fresh water utilizing waste heat from industrial processes has been identified globally as a research priority.About 15% of the electricity required to produce aluminum is lost as waste heat in the off-gas. However, the low temperature (low grade) of the heat limits reuse. The off-gases contain 50-150 ppm SO2 ; tightening regulations coupled with increasing coke sulfur levels are motivating SO2 control, for which seawater scrubbing is attractive for smelters with suitable access.We describe a process that produces fresh water, utilizing the waste heat while scrubbing SO2 . It uses direct contact between seawater and off-gas to humidify the off-gas. The vapor is subsequently condensed. In smelter trials, a unit treating a slip stream produced high quality water in the anticipated quantity, attaining over 95% SO2 scrubbing. Future work involves scaling the process to be economically attractive.BackgroundPopulation growth, coupled with industrialization and urbanization, are increasing demand for water. Water scarcity already affects every continent. Around 1.2 billion people, or almost one-fifth of the world's population, live in areas of water scarcity, and 500 million people are approaching this situation. By 2025, 1.8 billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world's population could be living under water stressed conditions (< 1,700 m3 per person annually) [1]. An assessment by the U.S. General Accounting Office revealed that under normal conditions, by 2013, water managers in 36 states in the USA anticipate water shortages, and that the number might grow to 46 states under drought conditions [2].The obvious choice to alleviate water scarcity is the 97% of available water in the oceans, which is saline and requires desalination for use in biological, agricultural and industrial applications. Technologies developed for desalination include Thermal Distillation, Reverse Osmosis (RO), Electro-Dialysis, and Vacuum Freezing. Distillation and RO are the most commercially prominent. Thermal distillation technologies include Multiple Effect Distillation (MED) and Multi-Stage Flashing (MSF). The report commissioned by the World Bank [3] is one of the many excellent references on desalination technologies. According to the International Desalination Association working paper [4], there were more than 17,348 industrial scale desalination plants installed or contracted by 2004. The total production from these plants is on the order of 8.3 billion imperial gallons per day. RO provides 47.2% of the total capacity. The leading thermal process, MSF, provides 36.5% of the total capacity. Although MSF and RO technologies currently provide the most cost effective means for desalination, their drawback is that they are very energy intensive, and whether or not they remain cost effective strongly depends on energy prices and energy supply."

Jan 1, 2012

By John F. Abel

In Silver Plume, Colo., there is a bachelor miner who offers individualized tours of his mine, The Silver Cloud. It is an interesting tour because he drove the mine himself and the view from the shack up there is spectacular. Beside that, he will probably invite you into his kitchen to sit around the old cook stove and drink coffee. When Andy first started his tour business he put a sign on the main street to advertise the fact. The sign read in part: "Women not welcome, but they will be tolerated at $3.00 a head”- the usual fee is $2.50. The sign lasted about 48 hours. Andy had to take it down because "all the ladies in town got mad at me. Now I take them all for $2.50 right across the board," he says. The mining industry is not only reticent about hiring women but traditionally does not even permit women to enter some mines. It would appear, what with the recent action on an equal-rights-for- women amendment in Congress, that we may be wise to examine the prospect.

Jan 1, 1970

By J. P. Hugo

Nuclear energy - its interactions with mining and metallurgy - PRESIDENTIAL ADDRESS given by J. P. Hugo Pr. Eng., B.Sc (Eng.) (Rand), Ph.D. (Sheffield) Energy is the life blood of the modern technological era in which we live and it was, I think, Benjamin Franklin who said that the manipulation of energy was the basis of all science and technology. This is perhaps an oversimplification, but there can be little doubt that our life today, and the improved standard of living we aspire to, are governed almost entirely by our ability to generate and manipulate energy. This ability has made it possible for Man - each specimen a feeble twentieth of a horsepower - to travel to the moon, to recover valuable minerals from the depths of the earth, to do arithmetic at unbelievable speed, to lessen the drudgery of manual labour. For these and virtually every aspect of our life we are dependent on energy from external sources. It is, therefore, not surprising that the per capita consumption of energy, and more particularly electricity, has become one of the most reliable criteria by which to measure the standard of living and technological advancement of a country.

By William Braden

This paper is presented in the hope that it will be instructive in view of the future large expansion of the mining industry in the west-coast countries of South America. There is a more or less general impression that the Spanish-American workman is inferior to the American, but after some years of experience and observation I doubt the correctne~s of this view. Taking into consideration all the elements which make for efficiency of labor, it has been found, particularly in Chile, that under proper organization native labor yields as much, man for man, and more, dollar for dollar, than in the Western United States. If a manager is willing to accept unreservedly the costum-bres del pais, without combating intelligently and patiently the ones tending to inefficiency, he should expect no better results than he deserves. He must conscientiously insist that a " square deal" be given and exacted; that liquor be excluded from camp as far as possible; that comfortable quarters and other uplifting elements of life be provided; and that past and existing methods and customs shall not be over-ridden rough-

Jan 1, 1910

By Donghai Li, Cheng Pan, Pan Chen, Xuewei Lv, Mei Liu

"Chromite concentrate after beneficiation can not be directly used in the electric furnace. Therefore sintering is one of the effective way to agglomeration, by which the chromite concentrate can be utilized and the power cost of ferrochrome smelting can be reduced. The properties of raw materials and the sintering process of chromite concentrate were studied in this work. The results showed that chromite concentrate used can hardly granulated alone, while chlorite addition can improve the effect of granulation. Moisture plays an important role in sintering process. The granulation effect is optimal when the amount of water addition is 12%. Strength and abrasion index are the evaluation indexes of sinter quality. It was found that the strength of sinter increased with coke dosage increasing to 12%, and then decreased when it continuously increased. Opposite regularities were found for the abrasion index of the sinter.1 IntroductionChromium is a very important metal element which is mostly used in the production of stainless steel. In the earth, it is always formed compound with iron as ferrochromium spinel (FeO.Cr203), and its mineralogical name is chromite.[1] Currently, the global production of chrome ore is about 20 million tonnage every year , in which fine ore (less than 8 mm) accounted for about 80% [2] Although the price of the fine ore is cheaper than the lump one, too much fines will lead to the poor permeability and causes increased electricity consumption while producing ferrochrome. Therefore, the agglomeration process of chrome ore is one of the effective measures to increase the usage ratio of fine ore."

Jan 1, 2013

By S. A. Davis

In July of 1996, the Kroll process began production again at TIMET&apos;s Henderson, NV, manufacturing facility. This, after being shut down for several years due to low market demand for titanium. Faced with limited pond capacity and increasing costs for water and wastewater disposal and storage; process changes were made to recycle water used to wash Kroll titanium sponge back into the sponge leaching process. This idea was revisited from 1992-93, when three consecutive attempts to recycle water for this application were unsuccessful due to early pump failure. Since it was uncertain why previous attempts failed, a complete understanding of the existing system was first sought. This included reviewing piping and flow diagrams; taking field measurements for all the piping, valves, and fittings; analyzing the wastewater composition; and modeling the fluid dynamics and control of the system. The fluid dynamics of the system were modeled by breaking the piping network up into nodes and applying the Bernoulli equation to each segment. The fluid flowrate control valves were modeled for this purpose also and the models were used to help specify the required processing equipment and control ranges and tolerances. Once the project was completed, an operating procedure was prepared for operation, startup, and shutdown of the washer water recycle system.

Jan 1, 1999

By S. S. Peng

In this paper, the precise definitions for a number of commonly used subsidence parameters are given. The subsidence parameters have been determined using an integrated approach for 110 subsidence cases collected in the major US coal fields. Attempts have been made to establish empirical formulae for the parameters. The results of this study indicate that some traditionally-held concepts should be changed.

Jan 1, 1995

The paper describes the propensity of tin to form intermetallic compounds with microalloying elements such as Nb, Ti and aluminium, which are commonly used as additions to achieve particular combination of strength and toughness. Two series of alloys were prepared by arc melting under an argon atmosphere. Each series was based on Fe, Sn and A1 with either Nb or Ti additions. The microstructures were studied using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy and microprobe analysis. It was found that the level of Nb addition has an effect on the formation of Sn-rich compounds. For small Nb additions, no Sn containing compounds were found, whereas in higher Nb alloy, a Laves phase (FezNb, hexagonal, a = 0.4830 nm and c = 0.7879 nm) containing about 1 at % Sn was found. A FezNb3 phase (cubic, a = 1.1261 nm) associated with the formation of alumina was also found but did not contain tin. No Sn containing compounds were found with Ti additions. The experimental observations have been compared with thermodynamic calculations performed using MTDATA.

Jan 1, 1999

By Foluke Salgado de Assis

Natural fibers are attracting the interest of engineering sectors owing to specific advantages such as lightweight and lower cost as well as for their inherent condition of being renewable, biodegradable, recyclable and environmental correct material with respect to CO2 emission. The banana fiber is nowadays recognized by its mechanical properties. It is known that with the increase of fibers volume fraction the composite significant increases its tensile strength. This was obtained with amounts up to 30% in volume of banana fiber. However no higher volume of fibers was able to be molded in a composite plate until now. Thus the present work aims to study higher volumes of fiber in terms of the influence on the tensile strength of specimens prepared under 5 tons of pressure. The fibers were previously washed and dried in an oven at 60ºC, after that poured together with the epoxy resin and catalyst mixture in the metal molds bone-shaped, and pressured to ensure specimens quality. The tensile strength increased significantly with higher amounts of banana fiber incorporated in the epoxy matrix. This better performance can be directly related to the fracture obstacle imposed by the fibers as well as the type of cracks resulting from the fiber/matrix interaction.

Aug 16, 2017

By K. J. Martchek

"This introductory presentation will highlight recent efforts to quantify the positive value of recycling metals such as aluminum, magnesium, lead, zinc, nickel and copper in relation to the three pillars of ""sustainable development"" - environmental protection, economic development and improve social consequences.This presentation will provide an overview of life cycle assessment profiles increasingly being utilized by customers, regulators and environmental advocacy groups to holistically evaluate the environmental performance of materials and products. The environmental profiles of prodi.lcts containing recycled metal will be presented based on rules established by the International Organization for Standardization (ISO).Significant to the life cycle profile of metal products is recent confirmation. that recycling has the potential to reduce materials production energy consumption by 95% for aluminum, 80""/o for magnesium and lead, 75% for zinc, and 70% for copper. Furthermore, . ""metals are eminently and repeatedly recyclable, while maintaining all their properties (1 ). "" Their durability relative to many hydrocarbon based materials enhance .their life cycle performance. However, the persistence of metals when dispersed into our natural environmental makes recovery and recycling particularly important Overall, when considering life cycle effects, recycling is critical to a sustainable future for metal products.Finally, regional and international regulations will be highlighted which will effect the efficient recovery and recycle of metals and their overall contribution to environinental protection, economic development and the enhancement of society."

Jan 1, 2000

By Kumar Ranjan, Kumari A. V. Asha, G. E. Sreedhar, Banerjee R. Raja, M. Narasimha, R. Shivakumar

In this paper, numerical simulation of magnetite, medium segregation and coal partitioning have been made in a 350 mm diameter cyclone. An attempt is made to assess the nature of impairment in efficiency in relation to the increasing amount of near gravity materials in coal. The CFD model approaches the Algebraic Mixture (ASM) model with the granular option and Reynolds stress model (RSM) to resolve the air core and turbulent mixing of the medium and coal particles. The partition characteristics of the DMC were modelled using both Lagrangian & Eulerian particle tracking for particles ranging in size from 0.5 to 8 mm and in density from 1200 to 2000 kg.m-3. Lagrangian frame work based Discrete Phase model used to simulate the coal particle trajectories inside the DMC and attempted to understand the residence time of different size and density coal particles. It was observed that coal particles having density near to separation-density (having fifty percent of probability to under flow and overflow) are exhibiting increased residence time than any density particles. As expected the smaller size coal particles shows higher residence time than the coarse coal particles. CFD simulations on effect of NGM mass fraction are simulated and analyzed using ASM model including for coal and magnetite. Coal particles with high NGM content show significant effect in misplacement of coal particles towards wrong products at all relative densities. The residence time of the particles increases because of its increased interaction with near dense particles. The effect of NGM fraction on overall cyclone performance as well as detailed flow assessment in terms of residence time distribution, NGM particle concentration profiles with respect to LZVV is presented.

Jan 1, 2018

By K. Murase

Potentiostatic electrodeposition behavior of dendritic copper from acidic copper(I) chloride (cuprous chloride) baths containing sodium chloride and sodium bromide was investigated. The morphology, or appearance, of copper dendrite and the sodium content in the dendrite as an impurity were both influenced by deposition potential (0 to ?150 mV vs. SHE) and bath temperature (R.T. to 60 C), while the current efficiency for the deposition was 99% or more irrespective of the deposition conditions examined. The bath pH did not affect the deposition behavior in the pH range of 0 to 2. Bath temperature was found to be the most important factor influencing the deposition current. The current density of the dendrite deposition on a titanium cathode was lower than that onto a copper cathode with the same substrate surface area. The reproducibility of the current for the dendrite deposition was poorer when an as-polished titanium cathode was used, although it was improved by surface treatment of the cathode with an HF-HNO3-H3PO4 solution before electrodeposition. The deposition behaviors were discussed with the potential-pH diagram of the Cu-Cl-H2O system.

Jan 1, 2007

By Albert Arents

This test is based upon the fact that metallic copper will precipitate gold and silver upoil its surface from acid solutions. Of course, the fact is not new, but its application is probably so. I have used the method with success; it recommends itself by the rapidity and ease with which it may be carried on. An auriferous cyanide solution, if made acid with sulphuric acid and boiled with finely divided, pulverulent, metallic copper, will, within a short time, deposit its gold-content on the copper. Any silver in the solution is also precipitated. If this mixture is now filtered, the filter and contents may at once be subjected to a crucible assay treatment, and its lead buttons cupelled and determined. If, instead of taking cement-copper, or any metallic copperpowder, a solution of bluestone is used after acidification, and a few small pieces of sheet aluminum are added, and the solution boiled until all the copper has come down, the result as to the precipitation of gold and silver is the same. This modification takes more time and attention in boiling. If aluminum has been used, it should go into the crucible with the filter and

Jan 1, 1904

By J. F. Nicholas

THE angles between the crystallographic planes in cubic metals were originally given by Bozorth and have been republished many times. Recently, Salkovitz2 tabulated the angles for the hexagonal metals (magnesium, zinc, and cadmium). he most commonly used metal which does not fail into either of these groups is tin, which has a tetragonal structure with an axial ratio of c/a = 0.54558 (99.99 pct purity, 25°C).² ccordingly, Table I has been prepared giving the possible values for the angle, 4, between planes of the types {HKL) and {hkl). The formula used was: Hh + Kk + LI — cos? = —--------------—-----------— A [(H2 + K2 + L2-a2c2(h2 + k2 + r;)] All angles are given correct to the nearest minute as this is sufficient for all practical purposes. Every angle depends in a different way on variations in the value of c/a, but even in the worst cases a variation of about 0.0003 in this ratio is needed to vary an angle by l&apos;, which corresponds to a temperature change of 20 °C or can be caused by impurities.

Jan 1, 1952

Masjid-i-Sulaiman Field.—During the past year, drilling activities have been limited to repair work. No new developments of importance can be recorded in production technique. Fall of dome pressure is maintained at the 1 lb. per sq. in. per annum rate mentioned in previous reports. Acid treatment of wells is being increasingly used and for wells in fissured areas has been very successful. Such wells have been converted into first-grade producers with substantial drops in bottom-hole differential pressures. The effect of acid treatment has been to increase the flowing lives of wells so treated. The normal procedure consists of threo treatments of 500 gal. commercial acid diluted 100 per cent but success has been met with fewer applications. The policy of returning products to the resorvoir has been continued. The total quantity of products returned since the policy was commenced in 1929 now amounts to approximately 30 million barrels. Haft Kel Field.—The drilling of the main Haft Kel structure for production purposes has now been completed. Production and control wells have been completed to meet the rate of production anticipated over the next few years.

Jan 1, 1937

This paper reviews an analytical model that defines the relationship of weight-weighted or volume-weighted average haulage distance with bench height and other related parameters; presents the optimum bench heights under various conditions in terms of minimising the weighted average haulage distance of ore/waste during the full lifetime of an open pit mine, and discusses the truck-haulage economics of mining open pits by high bench, specifically by 15 m, 18 m and 20 m bench through marginal analysis. The observations from these analyses disprove the previous conflicting assertions that the overall weighted average haulage distance either increases or decreases monotonically with bench height. It is concluded that: (i) an increase of bench height to 15 m from 12 m is likely to be viable under the general conditions of large-scale deep open-pit mines; (ii) the reduction of haulage cost is limited with the case of increasing bench height to 18 m from 15 m; and (iii) the feasibility of mining open pits by 20 m benches is generally questionable. These conclusions may serve as a useful guide for those who advocate open pit mining by high benches.

Jan 1, 1995

By R. V. Ramani, P. M. T. White, D. Sutton

3.1 Criteria for Selection A coal deposit has the following major characteristics: i) wide distribution as a flat-lying, thin, bedded deposit ii) stable nature of its major components and ranking characteristics such as carbon, heat content, volatile components, specific gravity, etc. iii) number of constituents and characteristics which under present regulations limit usage, such as content of ash, sulphur, sodium, etc. iv) effect of characteristics of over- and under- lying host rocks including porosity and permeability, lithology and general geology v) low value, high bulk nature. Because of the relative stability of its major components and its low unit price, coal does not require the same attention to detail as do the metal deposits. However, new regulations combined with social pressures make it imperative that more accurate information be made available concerning factors which affect the quality of coal and which may have an adverse effect on the environment when the coal is mined or burnt. The method selected for the evaluation of a coal deposit must, therefore, be flexible and sensitive enough to be used to interpolate stable parameters whose general distribution character-

Jan 1, 1974

There were present eleven Directors, the Secretary and Assistant Secretary of the Institute, and eleven guests. The Secretary, Bradley Stoughton, was appointed the representative of the Institute on the Board of. Directors of the American Bureau of Welding. A communication from a member of the Institute regarding simplified spelling was laid on the table. The following appropriations were made for the year. 1919: $250 to the Institute of Metals Division, $250 to the St. Louis Section, $100 to the Columbia Section. An invitation was received from the Western Society of Engineers to the Institute to use the facilities of that society during the A. I. M. E. Meeting in Chicago. The Bulletin of the Institute was presented to the French Congress of Engineers. There were elected twenty-eight members, eighteen associates, and three junior associates. The status of one member was changed from junior associate to associate. Four members were reinstated. An extension of time was granted to one member for payment of dues. The dues of four members on active military duty were suspended. Dues were remitted of four members who have been paying over thirty years, and who are each over seventy years of age.

Jan 5, 1919

By Edward Walsh

The difficulty of securing for experimental research the actual conditions to be found in practice very frequently deters many from engaging in such work. Probably no metallurgical operation is more difficult to imitate in the laboratory than the blast-furnace process. So many complex reactions take place within the furnace, under such varied conditions of time and temperature, with innumerable mechanical, physical, and chemical mutations, that while the results reached may approximate those obtained in practice, there is always something wanting. Much work of this kind has, nevertheless, been done, and is now being undertaken. We are indebted to the bold minds who have attempted it for our present real knowledge of the blast-furnace process. Not that those who have performed series of experiments at a few given temperatures can claim the honor. It required more than this—the ability to make a summary of all preceding experiments, to supply those which were wanting, and to confirm those that were doubtful. Sir I. Lowthian Bell, whose able papers before the Chemical Society and the British Iron and Steel Institute (forming the basis of his great work, The Chemical Phenomena of Iron-Smelting) has

Jan 1, 1889