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By David Schlain

"INTRODUCTION Electrolytic manganese is produced by electrolysis of a solution of manganese sulfate and ammonium sulfate in a diaphragm-type cell, metallic manganoese being deposited on the cathodes and sulfuric acid produced at the anodes. The spent electrolyte is used to leach fresh ore that has previously been subjected to a reducing roast; the resulting leach liquor is purified and returned to the cell.The leach liquor produced at the Bureau of Mines pilot plant 3/ at Boulder City, Nev., contains 135 to 140 grams of ammonium sulfate and 32 to 36 grams of manganese (as sulfate) per liter, and has a pH of about 2.5. After neutralization to a pH of 6.4 to 6.6 with ammonia and thickening, 0.10 to 0.15 gram of hydrogen sulfide per liter is added to the liquor to precipitate the heavy metals, and after 15 to 30 minutes the precipitate is filtered off. Residual sulfides and colloidal material are removed by ferric hydroxide formed by adding a small amount of ferrous sulfate to the solution at a pH of 6.5 to 7.0 and passing air through it. The solution is then filtered and clarified as a precoat filter. Finally, 0.1 gram of sulfur dioxide per liter is added, and the solution is electrolyzed in an anode-in-diaphragm cell. The spent electrolyte coming from the cell contains approximately 10 grams manganese, 135 grams ammonium sulfate, and 45 grams sulfuric acid per liter."

Oct 1, 1946

By John A. Mavrogenes

The Texaco gasification system developed at the Monte Bello pilot plant efficiently bums petroleum-coke thereby producing syn-gas and electricity. This system produces more electricity than conventional burners, yet the only by-products are pharmaceutical grade sulfur and V -rich slag. Vanadium is known to exist in multiple valence states in compounds which possess a wide range of melting points and physical properties. Consequently, it becomes important to carefully regulate oxygen fugacity throughout the system in order to control vanadium valence state. Vanadium phase equilibria is presently poorly understood, in large part because of the multiple oxidation states of vanadium (-I, 0, +2, +3, +4, and +5) and the difficulty of unequivocally identifying the valence state(s) in many compounds. The operation of these gasifiers at approximately 1400°C is well above the melting point of V20S but considerably below the melting temperature of V02 and V 203. If J02 can be regulated to keep the burner within the V 205 field, slag material would more likely remain molten and more easily flow out of the bottom of the burner. In pure V oxides. the oxidation state is readily determined by microprobe analysis. where V20S (V+5) is 56% V, V02 (V+4) is 61.4% V, and V203 (V+3) is 68% V. However, V valence in multi-element phases (especially phases containing other elements of variable valence) cannot be resolved by microprobe analysis alone. Petroleum-coke gasification slags collected from within the gasifier under different oxidation conditions were studied by electron microprobe analysis (EMPA). X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman spectrometry in conjunction with microprobe analysis was found to resolve the valence of vanadium in the phases of these slags. Raman spectra collected from homogeneous single phase V-oxide standards in vacuum at low temperatures (-150°C) yielded peaks characteristic to each valence state. Gasifier slag samples are, however, much more complicated. Oxidized samples contain: fine grained (Ca. Mg, Fe. V) oxide matrix of variable composition, (Fe. V, Ni) spinel. (Fe, AI, V, Ni, Mg) spinel, V205laths, AI-Si glass blebs and Ni sulfides. Reduced samples contain: crystalline Ca-siIicate matrix, subhedral to euhedral (V, Fe, Mg, AI) spinel, subhedral V02, Fe and Fe-Ni sulfides, Fe-Ni alloys, and complex Ca-oxide matrix. The different spinel assemblages, the characteristic V-oxides and the distinctly different character of the matrices makes the oxidized and reduced slags readily discernible.

Jan 1, 1995

By R. E. H. Pomeroy

THE statistical data given in this paper are taken from the actual performance of the No. 2 reverberatory furnace of the Nevada Consolidated Copper Co., Me Gill, Nev., for a period of four months, from April to July, 1914. The principal furnace dimensions are: Length, 132 ft. ½ in. at the skim-line level; average width, 18 ft., 10 in. at the skim-line level. The roof is 7 ft. above the skim-line level at the firing end. The average area in the uptake flue is 36 sq. ft., and the area above the skim line under the vulcatory arch is 24.3 sq. ft. Fig. 1 shows a diagrammatic plan and sectional elevation of this furnace. The furnace is equipped with two 400-b.h.p. Stirling waste-heat boilers set in parallel. California crude petroleum is used for fuel and has a specific gravity of 16.5° B., flashing in open test at 199° F. The oil is heated to about 200° F. in a steam heater before going to the burners, requiring about 9 b.h.p. per furnace day to heat it from the line temperature to the burning temperature. Measurement is made by oil meter, checked daily by reservoir readings. The oil is fed by gravity (34 lb. static pressure) to seven low-pressure blast burners of the Steptoe type (Fig. 2). The blast for these burners is supplied at about 40-oz. pressure by a motor-driven Connersville blower of 42 cu. ft. capacity per revolution. The air supplied by the blower through the burners for atomizing the oil amounts to about 10 per cent. of the theoretical air necessary for complete combustion of the oil. The remainder of the necessary air enters the furnace through the burner openings in the firing wall. No checker holes are provided, and the charge holes in the roof are equipped with slide gates and "dog houses? to minimize air leakages. The combustion of the fuel, as shown by gas analysis at the front of the furnace, is practically complete, the carbon monoxide in the gases being less than 0.5 per cent.

Jan 2, 1915

By Walter F. Morton

La mina y la planta concentradora de Chilete de la Northern Peru Mining & Smelting Co., están situadas en Cajamarca, norte del Perú, donde en 1948 se encontraron cubicadas cantidades de minerales de plomo- zinc, que fueron añadidas a las reservas de la mina. Posteriormente se construyó una planta de flotación que permitió mejorar la filtración de los concentrados y a su vez aprovechar al máximo los minerales de la mena como la ganga, así como su concentración de valores económicos en los mismos.

Jun 20, 1954

By S. Yuan

Oxygen ion conducting yttria-stabilized zirconia (YSZ) tube was used to remove oxygen from molten Cu at 1373K. Outer surface of the tube was in contact with the melt and the inner surface containing a thin layer of porous Ni-ZrO2 cermet electrode was in contact with a reducing gas. The migration of oxygen species (O2-) from the Cu melt through the YSZ tube is accompanied by an equal and opposite flux of electrons maintaining electroneutrality. Without applying an external EMF, the fluxes are maximized by short circuiting the melt with the cermet electrode. For efficient oxygen removal, the YSZ tube must be thin, contact resistances should be negligible, and the electrodes must be porous and cover the entire electrolyte surface for charge transfer. This refining process is environmentally sound, can use reducing gases such as H2, CH4 and CO without running the risk of increasing H or C content of the melt.

Jan 1, 1993

By Henry M. Howe

A discussion of the paper published in Bi-Monthly Bulletin, No. 20, March, 1908, pp. 227 to 237, and No. 22, July, 1908, pp. 615 to 620. PROF. HENRY M. HOWE, New York, N. Y. (communication to the Secretary *) :-Mr. Hibbard's definition of steel would be the best yet offered were it not for its one defect, the vagueness or equivocalness of "fusion-process." Puddling is surely in one sense a fusion-process, and so are the charcoal-hearth or knobbling-processes. But what he says suggests the following definition, which seems to me a good one: " Steel: any variety of iron which is usefully malleable at least at some one temperature, and is either cast when molten into a malleable mass, or if not so cast can be much hardened by sudden cooling." It is not necessary in a definition that quantitative bounds should be set up, for instance, that the exact height at which dwarf apple-trees cease and standards begin, or at which hills cease and mountains begin, should be stated. These quantitative measures are proper for specifications and contracts, but are not necessary for purposes such as the present. HENRY D. HIBBARD, Plainfield, N. J. (communication to the Secretary t) :-Professor Howe's criticisms of my definition of steel are not, it seems to me, well founded, for the . following reasons: The term "fusion-process" has been used during the past quarter or half century to distinguish the crucible, Bessemer and Siemens-Martin processes from the puddling- and cementation-processes, and probably no one at all conversant with the art of iron-metallurgy would now mistake its meaning. Moreover, no steel-metallurgist is in doubt of the meaning of the term "hardened? as applied to steel. If it were really necessary to describe what is meant by the term then it would

Nov 1, 1908

By Peter Mason, Chris Walker, Mike Costello

The Phase I electrowinning system at KCGM's Fimiston Operation utilised the well proven technology of electrowinning precious metal values onto steel wool followed by calcining and direct smelting to bullion. The above process, while reliable and successful, was to some extent labour intensive. The Williams Mine in Ontario, Canada had published conditions under which precious metal values are electrowon onto woven stainless steel and directly removed using high pressure sprays. The current paper describes the testwork which was carried out to check the applicability of the Williams criteria to KCGM eluates arising from the elution of highly loaded carbon from the calcine circuit and lowly loaded carbon from the float tails circuit. Information is also given on the commissioning and opera­tional experience which occurred.

Jan 1, 1996

By Mason P, Waller C

The Phase I electrowinning system at KCGM's Fimiston Operation utilised the well proven technology of electrowinning precious metal values onto steel wool followed by calcining and direct smelting to bullion. The above process, while reliable and successful, was to some extent labour intensive. The Williams Mine in Ontario, Canada had published conditions under which precious metal values are electrowon onto woven stainless steel and directly removed using high pressure sprays. The current paper describes the testwork which was carried out to check the applicability of the Williams criteria to KCGM eluates arising from the elution of highly loaded carbon from the calcine circuit and lowly loaded carbon from the float tails circuit. Information is also given on the commissioning and operational experience which occurred.

Jan 1, 1996

By А. А. Vasiliev, Y. G. Seredkin, А. V. Aksenov, А. Y. Senchenko

Refractory gold-containing concentrates usually contain gold enclosed in sulphides as well as in rock-forming minerals. Another difficulty is that gold often occurs as very fine inclusions of several micrometres, and even smaller than 1 micrometre, or can be part of the mineral composition at the structure level. Processing of such concentrates is a challenge. Ultrafine grinding and further oxidation are applied for gold liberation. The paper deals with the results from the study of gold deportment using Qemscan, and atmospheric oxidation testwork involving Albion Process™ on a gold-containing concentrate with a high content of refractory gold in sulphides and gangue minerals. Albion process testing was performed at Institute TOMS with the participation of Glencore Technology Pty Ltd (Australia). Additionally, conventional cyanidation testwork was carried out for the concentrate processing. As an alternative technology of gold liberation, oxidising roasting with arsenic stabilisation was used. The results from the study make it possible to assess the efficiency of the above-mentioned methods of gold liberation, and applicability of Albion technology to recover gold from the refractory concentrate. Key words: Gold, refractory concentrate, Albion Process, atmospheric oxidation, oxidising roasting, leaching

Jan 1, 2020

By A. Elsayed

Lightweight metals such as magnesium show potential in replacing aluminum alloy castings for engine cradles, cylinder heads and transmission cases. Unfortunately, magnesium alloys are susceptible to entrapping oxides and other impurities during casting that hinder strength and ductility. The current study examined various filter sizes and configurations with the aim of improving the mechanical properties of permanent mould cast AZ91E. The unfiltered casting had a yield strength, tensile strength and ductility of 93.3 MPa, 153.3 MPa and 2.2 % respectively and increased to 96.5 MPa, 167.0 MPa and 3.1 % with the use of a fine mesh filter within the well of the mould. The increased strength and ductility was likely due to the filtered castings containing fewer inclusions on their fracture surfaces as compared to the unfiltered castings.

Jan 1, 2011

By A. Bendada, P. Servais, X. P. Maldague, C. Ibarra-Castanedo, C. Mohr

Infrared (IR) thermography is a nondestructive, non-contact and non-intrusive technique that allows the fast inspection of large and complex structures with limited accessibility. Pulsed thermography is particularly interesting for the inspection of aerospace materials such as composites given that, after submitting the specimen surface to a thermal front, the most common types of subsurface discontinuities (e.g. porosity, de laminations, dis bonds, fiber breakage and inclusions) can be detected with an IR camera as regions showing abnormal temperature patterns. We present first the case of an aircraft door with water ingress and surface repairs on its honey comb structure. We also highlight the advantages and limitations of thermography for the inspection of aircraft composite parts, such as edge flaps, rotor blades and speed breaks. Finally, we expose some results from a Kevlar® non-planar specimen with Teflon® inclusions at different depths and locations.

Jan 1, 2006

By W. K. Choi

Stainless steel exposed to wet environments at ambient temperature is subject to the formation of a surface biofilm. Depending upon the prevailing environmental conditions (dissolved oxygen, pH, Eh, concentration of cationic/anionic species), the biofilm may stimulate corrosion through formation of differential aeration zones and concentration cells. Corrosion significantly impacts the United States economy, since on a yearly basis, corrosion induced losses are estimated to be over $200 billion. A large portion of this corrosion is imputable to bacterial activity, and basic information is needed for a better understanding and control of the biocorrosion phenomenon. The present study has investigated the influence of Thiobacillus ferrooxidans in the corrosion of American Iron and Steel Institute (AISI) 304, 316 and 416 stainless steel samples. The formation of biofilm and microstructural changes on the surface of stainless steel samples and their weldments were assessed by microscopic examination, and the changes in the mechanical properties by stress-strain measurements. The significance of the results will be discussed.

Jan 1, 1993

By Jennifer B. Leinart

Sixty percent of the mines responding to the sixth annual Mining Cost Service labor survey reported increases in wages averaging 3.4% over the preceding 12 months. Only one mine reported a decrease in wages and this was accompanied by initiation of a substantial profit-sharing plan. Thirty-nine percent reported no change in wages. Thirty-seven percent reported using some form of incentive bonus plan. Mining Cost Service annually surveys coal, metal, and industrial mineral mines throughout the United States. Information about wages, benefits, and incentive bonus plans is part of an extensive data collection program to monitor cost areas of significance to the mining industry. This year, 131 mines responded to the survey. The data is collected by sending questionnaires to personnel managers at active mining operations. The information included in this article was taken from the returned forms, from labor contracts provided by some of the mines, and from followup telephone calls. This year's data was collected between November 1988 and February 1989.

Jan 1, 1990

By John J. Theiler

Early in 1963, the Inspiration Consolidated Copper Co., at Inspiration, Ariz., began a program to make automatic the lubrication of several critical points on their KW Dart 37SL haulage trucks. Prior to installation of the automatic lubrication system, all the haulage trucks were serviced by hand every three shifts. Now, with automatic lubrication, the service period has been extended to four shifts. What are the principal benefits to be expected from such a system? 1) Uninterrupted production; 2) extended machinery life; 3) good housekeeping; 4) lower maintenance costs. Of these points, the most important to truck maintenance are extended component life and lower maintenance costs.

Jan 5, 1965

By W. N. Hamilton

As a result of a test-drilling program conducted by the Research Council of Alberta in 1968, a gypsum deposit averaging 30 feet in thickness, with a chemical purity of 84 per cent gypsum, has been proven to underlie the Clearwater River valley for a distance of 18 miles at depths ranging from near-surface to 300 feet. This and other subsurface deposits in the vicinity of Fort McMurray, Alberta are the product of local hydration of anhydrite beds believed to be the water-insoluble remains of the leached Prairie Evaporite formation of Middle Devonian age, the thick salt section of which is preserved down dip. The effects of salt solution are seen in the disturbed bedding and the intermixture of greyish green shale with gypsum in the core, the shale content being responsible for the rather low chemical purity of the deposit. A similar gypsum deposit, but probably of higher purity, is postulated to occur beneath the Athabasca River valley about 60 miles north of Fort McMurray.

Jan 1, 1969

The reduction of zinc from slags by a molten, carbon-saturated bath was examined in a laboratory study under conditions of continuous slag feeding. The results show that it is possible to reduce the bulk of the zinc from the slag before there is a net reduction of iron. However, the recovery of zinc was not as high as in batch tests performed in an earlier study. Lead in the slag was reduced simultaneously with the zinc to very low levels and was volatilised. Copper in the slag was reduced and dissolved in the alloy. An attempt was made to identify potentially commercial ways of treating zinc slags using an iron bath. The approaches that appear to have the greatest potential are reduction in a batch process using electrical heating and reduction in a continuous process with co- or countercurrent flow of the slag and alloy. In the latter the alloy would be prepared in a separate furnace before being contacted with the slag. The purpose of this would be to superheat and carburise the alloy so that no additional heat or reductant would have to be supplied in the slag-alloy reactor

Jul 1, 1991

By C M. Stewart, P Bowen

McArthur River Mine, in the Gulf Country of the Northern Territory, exploits one of worldÆs largest deposits of zinc, lead and silver. It was officially opened in September 1995, 40 years after its discovery in 1955. This paper describes the geological, engineering and metallurgical assessments which made up the feasibility study. It then relates how these study components compare with the first two years of operation. The challenges that had to be overcome before the McArthur River Mine became economically viable included the metallurgical problems associated with extremely fine grained ore and the development of an effective mining process.

Jan 1, 1998

By K. Krishnapisharody, G. A. Irons

"The modeling of gas-liquid plumes in steelmaking ladles has been the subject of many investigations. In most studies, the “modified” Froude number, based on the momentum of the injected gas, has been employed to characterize two-phase plumes. This approach has several shortcomings and is critically reviewed in the present work. Based on an extensive review of previous work and theoretical considerations, it is demonstrated that the injected momentum and consequently, the modified Froude number has no significance to gas blowing operations in Ladle Metallurgy. Instead, an approach based on the “plume” Froude number, previously shown by the authors as the proper form for Froude similarity, is extended as a simpler alternative.IntroductionGas injection is central to most Ladle Metallurgy operations. During ladle processing, the steel melt is usually stirred by an inert gas like Argon through porous plug(s) fitted in the bottom of the ladle or a lance inserted deep into the melt. The purging serves several purposes viz., homogenizing the melt, flotation of inclusions, enhancing the rates both of refining reactions and dissolution of alloying elements and promoting inter-phase interactions in the ladle.The topic of gas injection into liquid baths has been the subject of several investigations in the past. A great deal of this work, both experimental and computational, was devoted to describing the structure and properties of two-phase plumes as reviewed recently [1]. Generally, the ascending two-phase mixture is sub-divided into three distinct regions [2]: the jet core, transition and the bubble plume, respectively. The jet region, where the momentum of the injected gas is transferred to the bulk liquid, is also called the ‘momentum region’. In a similar manner, the plume is called the ‘buoyancy region’ where the motion of liquid is caused by the buoyancy force exerted by the bubbles. The proper characterization of these regions is important for the analysis and modeling of stirring operations in Ladle Metallurgy. Although many mathematical correlations exist for this purpose, some issues of theoretical and practical interest to the modeling of gas-liquid plumes need further attention."

Jan 1, 2012

By M. J. Laurila

Simulation of coal preparation circuits is becoming a widely practiced technique used for the design of coal preparation plants. On a much more limited basis, simulators are finding application in off-line process control. A typical application in the latter category involves inputting projected coal washability data for a shift into the simulator and using the software to optimize product quality and recovery within a range of predefined specifications. The plant is then operated at SG?s of separation determined from the simulation exercise for the one shift time period. This procedure is useful in that it incorporates some form of advanced planning into preparation plant operations. There is an attempt made to reflect changes in feed coal quality on a shift by shift basis rather than continually running the plant near design specifications with changes in SG?s of separation being made in response to an inadequate sampling program which only provides a spot measurement of material that has already passed through the plant. Instead of instituting changes on a shift by shift basis, NHI has proposed a method whereby monitoring three major operating parameters, * Feedrate to jig * Flowrate from hydrocyclone overflow * Density from cyclone overflow the ongoing plant operating performance can be accurately predicted on a continual basis, i.e., updated hourly. Using a distribution curve to predict the split between the clean coal and refuse from a given separator does not account for variations in efficiency that occur as a result of variations in operating parameters. NHI and Arch have studied the effect of both jig loading and solids content in the recirculating load to the jig on product quality. As a result, relatively simple measurements can be made on-line in a preparation plant which will provide input data to the simulation program that enables the prediction of jig/hydrocyclone circuit performance on a real time basis.

Jan 1, 1985

By Joseph D. Martinez

"The benefits of modern technology can readily be identified with energy availability. A clear correlation has been established between per-capita energy consumption and the GNP for various nations. The United States is an outstanding example of a nation which has benefited from vast energy reserves. The nation is now challenged, how¬ever, by dwindling reserves and the need to develop new sources consistent with the preservation of environmental quality. The development of new, virtually inexhaustible and environmentally acceptable sources cannot be expected for several decades. Meanwhile, we will have to depend on coal, nuclear energy and/or rigorous conservation measures.The net effect of environmental considerations has been to delay and perhaps ultimately eliminate the nuclear energy option as a national energy alternative. This forces a more positive move toward coal as the next major source of electrical power. Our coal resources are large, but the use and production of coal is also a threat to the environment. Thus, we seem to be moving from one major accessible source to another due to environmental concern only to face the probability that the alternative is also environ¬mentally unacceptable.Controversies revolving about energy choices must be resolved by an analysis of the relative benefits and impacts of these two sources and others. The pattern of changing energy sources is not new. We have moved from wood to coal to oil and gas in the past and must learn to adapt in the future. Rational decisions must be made relative to the utilization of intermediate energy sources pending development of promising future approaches. A collapse of current levels of energy supply could threaten our technological society and the means to develop a new energy base."

Jan 1, 1976