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By Charles Maier

PART I DENSITY AND ENERGY CHANGES IN COLD-WORKED COPPER IT has long been supposed that when crystalline materials are com-minuted the energy used in the production of increasingly smaller grain sizes is not entirely dissipated as heat but that a certain portion is "stored" as a part of the internal energy of the material. This portion usually has been called the "surface energy" of the particles. The practical interest of the Bureau of Mines in this subject in connection with the energy requirements of crushing processes has led' to the author's attempt to measure the "stored" energy in finely divided calcite by heat-of-solution methods1. The experiments on calcite showed that "storage" of energy could not be proved for this material, because fine grinding caused a lack of chem-ical homogeneity evidenced by loss of carbon dioxide and subsequent adsorption of water on the surfaces of the calcite particles. When thermochemical correction was made for composition changes the cor-rected heat of solution was less for fine material than for coarse. Con-tinuation of the experimental work into the problem of comparing work and heat in the deformation of metallic crystals, where the calorimetric difficulties were less, showed, however, that in the case of copper and aluminum a real discrepancy between work and heat could be shown. Similar results had previously been obtained by Farren and Taylor2 and Hort3 and more or less simultaneously with the author's work by

Jan 1, 1936

By W. G. Davenport

Chapter 1 showed that flash smelting is a key step in extracting copper from sulfide ores. It also showed that there , are two versions of flash smelting: (a) Outokumpu flash smelting, which uses oxygen-enriched air blast and injects dry feed downwards into a hot furnace (b) lncoflash? smelting, which uses industrial oxygen blast and injects dry feed horizontally into a hot furnace. This chapter describes Outokumpu flash smelting.

Jan 1, 2001

By J. H. Swisher

The solubility of graphite in CaO-S2O2-Al,O3 slags was measured by equilibrating slag samples with graphite crucibles and CO gas. Carbon contents as high as 2 ut pct were obtained in CaO-saturated, CaO-A1,O3 slags, and 1.3 wt pct in slags of the composition CaO.Si0,. Although the observed conditions for Sic formation were in agreement with those predicted from thermodynamic data, CaC, was found to form at a lower temperature than predicted frotn thermodynamic data. From measurements of the equilibrium carbon content as a function of CO Partial pressure, it was found that carbide ions dissolve in CaO-A12O3 melts with a valence of minus two. The carbon content increased with CaO concentration in Ca0-Al,O3 melts and increased with SiO, content along the CaO'AlO3-CaOSi0 join in the ternary system. When solid CaC2 was added to CaO-A12O3 and CaO-SiO2-A12O3 slags, it was found that one of the oxides in the slag was reduced by the carbide (Al2O3 in the forrner and SiOz in the latter). In electric furnace steelmaking, a double-slag practice is frequently used to meet alloy specifications. Initially a flush slag, which is oxidizing in nature, is used to remove phosphorus and carbon from the steel bath. Later in the refining period, the flush slag is replaced by a highly reducing carbidic slag. When calcium carbide is formed in or added to a finishing slag, the slag is effective as a desulfurizing agent and also permits alloying elements such as chromium, vanadium, and tungsten to be added to the slag in the form of oxides. The oxides are readily reduced by calcium carbide, thereby minimizing the use of expensive ferroalloys. More work has been done on the thermodynamics of silicon carbide in slags than on calcium carbide. Baird and alor' and Kay and alor' determined the free energy of formation of Sic by measuring the partial pressure of CO in equilibrium with solid silica, silicon carbide, and graphite. Using a similar technique, they determined SiOz activities in CaO-SiOz and Ca0-Si0,-A1203 slags. Rein and chipman3 also determined the free energy of formation of Sic using slag-metal equilibrium measurements. A literature survey has uncovered only one experimental study of the behavior of CaC, in slag systems. Shanahan and cooke4 report the results of some preliminary experiments on the solubility and stability of CaC, in a CaO-A1,03 and a Ca0-Si0-A1,03 slag at a temperature of about 1500". The carbon solubility as CaC, in a slag containing 50 pct CaO and 50 pct A1203 was reported to be 0.6 pct. They also review earlier work on the binary CaO-CaC, system. A eutectic exists in this system, but various investigators disagree on the eutectic temperature and composition. eal has given an explanation for carbide furnace erruptions in terms of the thermodynamic properties of CaC,; his analysis is not based on experimental data, but on compiled data for the free energies of formation of CaC, and CO.' , These data for steel-making temperatures are all extrapolated from the results of low-temperature measurements. In the experiments described in this paper, slag samples were equilibrated with graphite crucibles and with mixtures of CO and argon or with CO gas at 1 atm total pressure for measurement of the carbon solubility. Most of the work was done on Ca0-A1203 binary slags, although in some experiments CaO-SiO, and Ca0-Si0,-A1,03 slags were used. EXPERIMENTAL Slag samples of the desired composition for the solubility measurements were obtained by blending pre-fused master slags. The master slags were prepared by fusing mixtures of reagent-grade CaC03 with either A1,03 or Si0, in a graphite crucible. The master slags were crushed, then decarburized in air in a muffle furnace at 1200O C. A schematic diagram of the apparatus is shown in Fig. 1. The source of carbon for the solubility meas-

Jan 1, 1969

EARLY in 1911 the Public Service Board of New South Wales suggested the advisability of inaugurating a School of Mines at Broken Hill, arid made inquiries to determine how such an institution should be conducted. He, the author, believed the Board, as a result of the inquiries, was in favour of the project being worked in conjunction with the Technical College, and hoped to be ready to receive students at the commencement of 1912. That the inauguration has not yet taken place is probably due to the vast amount of consideration and preparation that a new departure of the sort would require. At the present time New South Wales or, to speak more broadly under the same denunciation, Australia is not at all suitably catering for the technical training of young men to provide the increasing demand for officers to work the valuable mines within its territory...

Jan 1, 1912

The use of QemSCAN in providing mineralogical input to detailed ore and product characterization has proved of immense value in recent years. In this paper, a brief review of selected Cu-case studies is presented to demonstrate the versatility of automated, quantitative mineralogy by QemSCAN. This versatility ranges from measurement and analysis strategies through to data processing and presentation. As a rapid diagnostic service, it is common to find that only grain size, the degrees of liberation and/or ore mineral modal mineralogy are of interest. By contrast, the detail afforded by the simultaneous determination of both gangue and ore minerals can alert mineral engineers to fatal flaws and attributes deleterious to processing that are directly a function of silicate and other gangue mineralogy. Examples of the latter effects include the influence of micaceous minerals and acid consuming species, while the former include fluorine minerals, which can provide both processing and environmental challenges.

Jan 1, 2007

The presentation of the John Fritz Medal to Professor Henry M. Hone will take place in the auditorium of the Engineering Societies? Building, 29 West 39t,h Street, New York, at 8:30 o'clock on the evening, of May 10. It is hoped that many members of the Institute will be able to attend this ceremony, and the committee desires to make special mention of the fact that ladies are cordially invited to be present.

Jan 5, 1917

By James Withers, Dongbo An, Jinhong Zhang

A micro-scale investigation was carried out by applying atomic force microscopy (AFM) to study in situ the adsorption of various collectors, i.e., oleic acid, octanohydroxamic acid (HA), and salicylhydroxamic acid (SHA), on bastnaesite in aqueous solutions. The obtained AFM images show that the surface morphology of bastnaesite changes greatly after it comes into contact with the solutions of the collectors, suggesting that all these collectors can effectively adsorb onto bastnaesite. Increasing temperature can facilitate the adsorption of oleic acid onto bastnaesite. Results from attenuated total reflectance–Fourier transform infrared spectrometry (ATR-FTIR) also show that all of these collectors adsorb strongly onto bastnaesite, with strong absorbance spectra being detected. The ATR-FTIR results confirm those obtained by AFM. In general, hydroxamic acid collectors (HA and SHA) adsorb onto bastnaesite mainly in the form of insoluble metal hydroxamate. This specific adsorption mechanism explains that a high selectivity with a moderate collectivity will be achieved with a hydroxamic acid collector for the flotation of bastnaesite.

MR. TESCHER (Disaster at Dawson) : I move that you appoint a committee of nine members of this Institute to draft a set of resolutions that we can send out to all members of this Institute, to the mine officials in all four states, that might go towards preventing these disasters; that we reach all men, all mining men, mine officials of all kinds. I think we have enough brains to carry out a few suggestions of that kind. I think you are fully familiar or know men who are fully qualified to act on this committee. The only qualification that I have is to ask that Mr. Harrington be appointed a member of this committee. PRESIDENT WHITESIDE: You have heard the motion, and I believe it was seconded. Is there any discussion? That is a subject that really needs a great deal of thought. MR. LAMB: Things like that can't be handled in a minute. What Mr. Tescher suggested is all right, but to my mind, going into a great many of these different properties, seeing the conditions, such things hit pretty close to home. I would suggest that you put this off; lay it over until such time as the people who had the disaster have some time to think these things over. It is too soon to offer even a suggestion. Suggestions are all right, but there are no nine living men in the United States who can stand up or sit down and talk it over and give you any reasonable answer, in one hour or six months. First, you would naturally have to go down there and converse with the men who were at the camp at the time. You are all operators; all you operators would -like to talk it over today. You realize that anything that is good for the camp is always acceptable in disasters of this kind. I say, do it gracefully and not by publication. MR. TESCHER: I feel that the men present know these suggestions by heart and they don't have to discuss them. They know them instinctively and they know they will apply to any mine. It must be understood that if these suggestions are not carried out, they ought to be; and there is a motion before the house. PRESIDENT WHITESIDE: Mr. Murphy, you started to rise to your feet a moment ago. Have you anything to say on the subject? MR. MURPHY: I have just returned from a visit to Mr. Brennan. Mr. Brennan and I have worked together for twenty years. The manager of our company asked me to go down there and express his sympathy. Those things come to all men if they live long enough, in the coal business, and he wanted me to express to Mr. Brennan personally his sympathy and deep regret. What I had in mind when I started to rise, was to suggest that the Institute as a whole express its sympathy to Mr. Brennan. I don't think there is a man in Utah, Wyoming, Colorado or New Mexico who has done more in safety' lines than Mr. Brennan, and it just seems bad luck that he had this disaster, and I am in hearty sympathy with the gentleman who spoke about not appointing this committee. I believe a resolution to Mr. Brennan would be very much better. JAMES DALRYMPLE: I am in sympathy with this gentleman here. I think it is going to hurt the feelings of those connected with the mines in which this disaster occurred. If you will give me the privilege for a few minutes, I will gladly express myself and the action that has been taken in the past by this Institute, and my opinion combined with a great many other opinions. And what I am going to say is going to be said by the-well, I am going to say it as I see it. I am going to say it not in an unfriendly spirit, but from a spirit of not undue criticism. I happen to be one of the original members who organized this Institute. I did what I could to obtain memberships. I remember very well when we had our first meeting that we had a very large membership. I think I have a photograph of the members which was taken on the steps of the Capitol building at that time. Our membership at that time was composed largely of underground officials. I mean by "underground" officials, the superintendents to some extent, the mine foremen, their assistants,

Jan 1, 1923

By Klimpel. R. R.

Acknowledgments I am honored to be named as a recipient of the Antoine M. Gaudin Award, and I would like to briefly single out four groups who deserve a special thank-you relative to this award. The first group consists of Professor Kawatra, the many international support references that he gathered and the Gaudin Committee itself. I know such things don't come without considerable effort by many individuals, and I'm grateful for their support. The second group consists of the management of The Dow Chemical Company, the managements of various mining companies and, in recent years, the management of G. S. Technologies, all of whom supported me, financially and otherwise, in my grinding, flotation and other particle-processing work. Operations people are the most overworked and under recognized people in the world, whether they be in the mining or chemical industry. Obviously, without extensive industrial support, especially from operating personnel in the mining industry, almost nothing about the work contained in this lecture would have, or could have, happened. The third group consists of a number of coworkers who have played key roles in specifically implementing the new flotation-product portion of this lecture. Of these, Bob Hansen, Don Leonard, Basil Fee, Simon Isherwood, Fernando Cones and Marty Meulendyke deserve special recognition. They have not only been dedicated, but they have been great to work with. Also in this third group are many members of the international academic community, especially those at Penn State. Professor Leonard Austin must be singled out because he took me as a young mathematically oriented chemist and taught me to be an effective process-oriented engineer. Without this experience, I would not have had the over 30-year career as an engineer, which I have loved. In addition, Len planted the size-reduction-research virus in my blood, which I can't seem to get rid of. I also need to mention Professor Frank Aplan, whose obvious love of mineral processing and froth flotation helped to create my interest in flotation. Thus, for those of you who don't like my approach to flotation, it's all Frank's fault. The fourth, and certainly not the least, group to thank is my wife, Charlene, and our two sons, Richard and Steven. No one could have a more supportive family. In every sense of the word, my wife has been my partner from the beginningwe were married at the end of my freshman year in college. She has sacrificed much for me, and I will never really be able to express the depth of my gratitude for Charlene's encouragement, loyalty and support over the past 36 years. General comments on froth flotation The industrial process of froth flotation: Where is it going? I'm here to tell you loud and clear that froth flotation is alive, well, and growing. The inherent characteristics of high mineral throughput per unit of capital, low operating cost per unit of feed, high mineral specificity and high operating flexibility have guaranteed froth flotation an important past and a growing future. As with any evolving technology, there are always trends at the industrial level that are primarily driven by economics. The current trends include: •the movement towards larger and larger equipment, •more alternative equipment designs (e.g., the column cell),

Jan 1, 1996

By K. Fountain

In Novemeber of last year I visited a mica mine in Hunan Province, China. For nine months , we had been trying to sell Chinese mica to a customer in Belgium. Talking to the customer was like negotitating with a stone wall. The buyer refused to communicate any -thing other than his steadfast refusal to consider Chinese mica. He would not advise us what he wanted, what specifications or grades. He would give no indication if our price at market, or reasonable, or totally out to lunch. He would not even accept samples. It took no genius to guess that the mica buyer had at some time in the past bought a shipment of Chinese mica and had received a disaster. I invited the mica mine in Hunan in order to see for myself what could be done - without massive investment in equipment and instruments - to upgrade the quality of the mica for export. We had seen this type of customer reaction before. One disgruntled customer who had pur¬chased pigment grade barites direct from China ranted and raved about unreliable and inconsistent quality. It did no good to explain to him that China is a big country, with hundreds of mines scattered throughout many areas, each producing a different product. Our further explanation that Chinese export organizations also varied in degree and efficiency of customer service fell on deaf ears. Samples had no effect on his perception. Eventually we showed him photoraphs of two mountains of pigment grade barites. One lot was our sales of pigment barites to a major European minerals processor. Our Chinese barites stood proudly white and beautiful next to a hill of other material which now appeared at best mediocre and dull by comparison, and which the buyer had decided to reject after he received our Chinese barites. Finally the customer was sufficiently impressed to look seriously at our guaranteed specification and the outturn analysis performed by our other customer.

Jan 1, 1987

By J. Gummer, M. Williams, S. J. Hawksworth

A common problem encountered in British coal mines is bearing failure on conveyor system idler rollers, which on occasions has led to fires. The UK Mines Inspectorate initiated a study of such failures to assess the potential for ignition of explosive atmospheres. As part of this study HSL have developed a system to measure the temperatures generated within the bearings during controlled failure. Temperatures are measured using both infrared thermal imaging and contact thermometry. The work to date has shown that temperatures well in excess of the auto-ignition temperature of methane can occur.

Jan 1, 2003

By Wayne E. Glenn

The San Miguelito Field of Ventura County, California, lies along the coast approximately five miles northwest of the city of Ventura. The structure is one of several in the Ventura anticline, a series of anticlinal folds trending northwest-southeast through the San Miguelito Field. The Ventura Avenue Field lies to the southeast along the anticline, and Padre Canyon and Rin-con Fields lie to the northwest; the series then extends beneath the Pacific Ocean. Production is obtained from the Lower Pico and Repetto formations of Pliocene age, and oil accumulation is controlled by faulting, lithology and structure. The first well in the First Grubb Pool was completed in November, 1931, and to date 48 producing wells have been drilled on the 276 productive acres. Approximately 685 ft of net pay are contained in the eight sand bodies grossing 1,220 ft of section. Production of oil to date has been 15,-600,000 bbl. A gas injection project was instigated in April, 1940, but was discontinued in September, 1949. This paper is confined to a discussion of the development and performance history of the First Grubb Pool of the San Miguelito Field. LOCATION AND GEOLOGY The San Miguelito Oil Field is located in Ventura County about five miles northwest of the city of Ventura along the coastal highway to Santa Barbara. It is located within sections 23, 24, 25, and 30 of Township 3 North, Range 24 West, San Bernardino Base and Meridian. Surface elevation in the field ranges from sea level to plus 1,200 ft, and the terrain is extremely rugged. The structure is well defined on the surface and on the wall of the Amphitheatre Canyon where appears a so-called "text book" anticlinal section. The San Miguelito structure is an asymmetrical, elongated anticline about two miles long and three-fourths of a mile wide. The trend of the axis of the anticline is northwest-southeast. Fig. 9 illustrates the contours and major faults of this structure. Dips on the southwesterly flank average about 40 degrees, whereas the northeasterly flank ranges from 60 to 75 degrees. There are several faults striking generally east and west. These faults do not appear to affect materially the area of accumulation or performance behavior. It is believed that accumulation was affected by steeply dipping beds and extremely low permeability of the northeast flank of the structure. As shown by the typical log, Fig. 1. the San Miguelito Field is divided into two stratigraphic producing intervals. The First Grubb Pool comprises the interval from the "G" to "L" markers; the Second Grubb Pool from the "L" to "M" markers. The First Grubb Pool, ranging in thickness from 1,105 to 1,680 ft, with an average of 1,220 ft, includes approximately 685 ft of oil-bearing sands. The First Grubb zone consists of eight sand intervals separated by shales. The shale bodies separating the eight sand intervals within the First Grubb Pool are continuous throughout the major part of the structure and serve as an effective barrier. Many of the thin, irregular shale or siltstone streaks within these sand bodies are discontinuous and do not affect well performance appreciably. The productive horizons in the First Grubb Pool are siltstones and sandstones of the Lower Pico and Repetto formations of Pliocene age. It is apparent from inspection of the typical log that the "G" to "L" interval might have been separated into at least six producing zones and selectively pro. duced. Unfortunately the electric log and some of our modern tools were not available or were in their infancy dur. ing the period 1931 through 1937. Not until 1937 when eight wells had been completed were there sufficient geological data to permit definition of the sand bodies. Then the problem of reservoir control in this multiple-sand field, where all sands are open to a common

Jan 1, 1950

By Louise Corriveau, Bronwyn Azar, Valerie A. Jackson, Luke Ootes, Jeff Harris

We use the results of new bedrock mapping, combined with geochemical point data and airborne radiometric data (in particular equivalent uranium concentrations) to help determine which geological units in the Paleoproterozoic Great Bear magmatic zone (GBmz) contain elevated uranium. The data collectively indicate that the highest primary uranium concentrations are in equigranular granites and subvolcanic/volcanic porphyries. Notably, these rocks host the majority of known uranium-bearing deposits and/or prospects in the GBmz. We speculate that the uranium in these deposits/prospects was derived from nearby, uranium-enriched rocks and was mobilized by much younger, circulating hydrothermal fluids. Sedimentary rocks of the Thelon and Dismal Lakes groups unconformably overlie the GBmz and are known to host unconformity-type and sandstone-hosted uranium prospects. Most likely, the uraniumenriched rocks of the GBmz acted as a uranium donor to these overlying sedimentary basins. The method of investigation employed in this study may be applicable to other ‘granitic’ terrains in order to identify regions with favourable rocks for uranium exploration.

Jan 1, 2013

By Kun Wang, Weipeng Luan, Qingbo Yu, Qin Qin

The oxygen uncoupling property of the oxygen carrier is essential for the chemical looping gasification process. In this paper,the combined Cu-based oxygen carrier were prepared by mechanical mixing method. XRD and SEM were used to characterize the oxygen carrier prepared. TG experiments were performed in a thermal analyzer to investigate the oxygen uncoupling property. The XRD pattern of the fresh oxygen carriers showed that the phases of the oxygen carriers were stable.The active phase of oxygen carrier was CuMnO. With the increasing of x 3-x 4 heating rate, the starting and ending temperatures of the reduction reaction increased. However, the reaction time decreased and the reduction rate increased. With the increasing of oxygen concentration, the starting temperatures of the reduction reaction shifted to high level. Temperature had great effect on the reduction rate and the reduction rate increased with increasing of the reduction temperatures.

Mar 1, 2018

By T. T. Read, F. C. Houghten

"The bad effects upon the health and output of miners that result when the ventilating current in a mine lacks sufficient cooling power have been described by Harrington and Sayers in a previous report (1)*** The normal temperature of the human body is about 98.5°F. and whenever work is done by the muscles, indeed even when sitting still, the normal bodily processes generate heat which must be given off, otherwise the body will become overheated and a number of bad effects will be produced. If it were possible to so enclose a man that he could continue to breathe and no heat could escape from his body he would die within a short time. In a series of experiments made at the Pittsburgh Station of the Bureau of McConnell and Houghton (2) found that a dry-bulb and a wet-bulb temperature of 112.5°F could he borne for only 35 minutes, even when the subject was at rest. A wet-bulb temperature of 100.4°F (dry-bulb 157°F) could only be tolerated for 45°F minute. Under such conditions the bodily temperature rises as much as 45°F above normal and the pulse is accelerated. Very uncomfortable sensations are felt when the pulse rate exceeds 135. The human body, like any other internal combustion engine, must be cooled in order to function properly.Under ordinary circumstances the air surroundings people is enough coder than themselves to permit this heat generated within the boiy to be river off with¬out difficulty. At higher temperatures, or when the rate of work, with its corresponding generation of heat is high, the body can not throw off heat fast enough, so it begins to sweat and the evaporation of the sweat cools the body. But the results of the experiments cited above indicate that in still air, even with the body at rent, it can not adjust its temperature when the air is above 90° wet- bulb. J. S. Haldane (4) says ""at a wet-bulb temperature of 60°F the actual amount of work done by the miner begins to fall off; as the wet bulb temperature rinse farther the work Bona gradually diminishes to the vanishing point. Then the temperatures indicated by the wet-bulb exceeds 85°F hard work in a mine seems hardly or the commercial working of a mine the wet-bulb thermometer should not in generaI, be allowed to rise above 80°F, unless perhaps where there it a good current."

Dec 1, 1923

By R. T. Sorensen

Research and testing in a small scale equivalent of a commercial flota-tion plant was completed on four low-grade, iron-bearing materials from the western Mesabi range. Closed circuit-flotation of calcium-activated silica with fatty acid collector developed data for comparison with the batch process and highlighted problems not evident from previous bench testing. The four ore samples contained from 27 to 39 percent Fe and were equally represented by nonmagnetic taconite and semitaconite type materials. Iron concentrates containing 6.0 percent, or less, SiO2 were made 5, all four samples. Of the two material types, the semitaconite was the ore amenable to treatment, yielding iron recoveries of about 90 percent as cc pared with 70 to 80 percent for the other. Pilot plant tests showed that concentrate grade made in batch tests could be duplicated in the closed circuit and demonstrated that the amount of recoverable middling iron varied considerably between ore samples. The continuous tests also showed that water temperature strongly influenced results in the treatment of one ore but apparently was of indifferent consequence in another. Progress in thickening and filtration of flotation concentrates was made through introduction of tapioca flour to serve the dual role of iron mineral depressant and flocculant.

Jan 1, 1966

By K. K. Kelley

The first bulletin (245)3 in this series, which appeared in 1932, summarized the entropy values then available for the elements and inorganic compounds, results being listed for some 150 substances. In the interim advances in the realms of spectroscopy applicable to the determination of thermodynamic properties and in the development of methods of calculation therefrom have added many highly accurate values. Moreover, through the efforts of Prof. W. M. Latimer (286) and his coworkers, satisfactory entropy values are now available for all but a few of the common inorganic ions in aqueous solution. At the same time rapid progress has continued in the study of low-temperature heat capacities in several laboratories, In addition, compilation and correlation of data pertaining to vapor pressures (247), thermodynamic properties of carbonates (258), thermodynamic properties of sulfur and its inorganic compounds (250), and the thermodynamic properties of metal carbides and nitrides (251), which were published as members of this series, have yielded many values. As a result, over 500 usable entropy values for inorganic substances may now be tabulated. This bulletin originally was planned as a second revision of the first member of this series, the first revision (249) having appeared in 1936; however, because of requests for the explanatory section of the first bulletin from those teaching thermodynamics, it was decided to com¬bine the information in the first bulletin and its revision with the data that have appeared since 1935 and to repeat the explanatory material in somewhat more detail. The purpose of this bulletin is therefore to give the available values of the entropies at 298.1° K. of the elements and inorganic compounds, together with enough explanation of the methods employed in calculating entropies to make the results comprehensible.

Jan 1, 1941

By P. G. Thornhill

EARLY in 1951, Falconbridge undertook a research program aimed at the development of a sulphate roasting process for the recovery of the non-ferrous rnetals from the nickeliferous pyrrhotite fraction of Falconbridge ore, in order to reduce the tonnage of iron entering the srnelter. Such a method, it was hoped, would permit a high recovery of the nickel from pyrrhotite otherwise entering the smelter feed, thus not only raising the grade of the latter and reducing its iron content, but also providing an iron oxide residue useful as a source of by-product iron ore. At an early stage in the exploratory laboratory test work it was found that the degree to which the nickel could be solubilized by the sulphating roasting treatment was limited by particle size and the ex-tent to which the pyrrhotite concentrates were freed of the nickel occurring as physically separable pentlandite, a mineral relatively difficult to roast. ( 1) Thus the program

Jan 1, 1961

By Xiaodi Huang, Matthew Andriese, Zheng Zhang, Jiann-Yang Hwang, Zhiwei Peng

"A simplified finite-difference time-domain (FDTD) algorithm for modeling microwave propagation in magnetic dielectric materials was developed and employed to study the microwave dissipation in magnetite. Heat transfer during microwave heating of magnetite was subsequently investigated by solving heat transfer differential equation using explicit finite-difference (EFD) method. It is observed that temperature of magnetite surface increases rapidly in the first minute due to the rapid strength decays in both electric and magnetic fields within a short distance along the path of microwave dissipation. A temperature peak, initially formed at the surface of the sample slab, migrates inward as heating time extends and microwave power increases.IntroductionAs one of primary materials in iron and steel industry, magnetite exhibits excellent microwave absorption capability, which leads to great energy conservation in microwave assisted steelmaking [1,2]. The fast temperature increase in microwave heating of magnetite can be attributed to both dielectric and magnetic losses [2]. Although much experimental work has confirmed this observation, detailed computational studies for modeling of microwave field dissipation in magnetite at commonly used frequencies, such as 915 MHz, has not been well addressed [1,3].Finite-difference time-domain (FDTD) method is widely used in computational electrodynamics modeling to simulate the dynamics of electromagnetic wave scattering from various media [4,5]. This approach requires modeling algorithm to be formulated with integration of specific characteristics of each medium. An extensive literature survey indicates that current formulations are only suitable for modeling electromagnetic waves propagating in normal dielectric lossy materials [5,6]. Since magnetite is a magnetic dielectric material in which both dielectric and magnetic properties contribute to the heating process under microwave irradiation, a specific algorithm should be developed for the simulation."

Jan 1, 2012

By E. A. Nesbitt

The important permanent-magnet alloys 15 years ago contained carbon and depended upon it for their permanent-magnet properties. In recent years great advances have been made in a number of new alloys substantially free of carbon. These include Remalloy,' an alloy of iron, cobalt, and molybdenum, the various iron-nickel-aluminum alloys of the Mishima2 type, and the more recent Alnico V3 in which the best properties are developed by heat-treating in a magnetic field. The Mishima and the Alnico types of alloys are very brittle and after casting must be ground to size. This article describes a permanent-magnet material4 that can be machined as cast, and when handled with some care can be rolled to thin sheet and drawn to fine wire. Optimum magnetic properties are developed by a simple heat-treatment, and at this time the ductility of the alloy disappears. If the cast alloy is heat-treated without cold-working the mag netic energy product is about 1.0 X 106. This material is called Vicalloy I (pronounced vicalloy, V for vanadium, I for iron, and C for cobalt). When the alloy is first hot-worked and then considerably reduced in area by cold-swaging, drawing or grooved rolling, it is found that after heat-treatment the magnetic energy product measured in the direction of previous extension can be increased to 2.0 to 3.5 X 106. These higher values have been obtained only after reductions in area of 75 to 95 per cent, and since the material hardens considerably during working, the reduction ordinarily can be accomplished only in fine wires, although larger sizes can be reduced by the use of powerful machinery. When the material has been cold-worked in such a manner as to improve its energy product substantially, it is called Vicalloy 11. Commercial use of Vicalloy has been made in the recording of speech. Tape 0.002 by 0.050 in. has been found superior in quality to all others tried, and is now used in the Western Electric Mirrorphone 5 In a variety of forms Vicalloy I or I1 is useful in many laboratory instruments, and in experiments in which the sizes and shapes required cannot be obtained with the other more brittle permanent-magnet materials. In 1936, during a study of other age-hardening magnetic systems, it occurred to the author that some of the iron-cobalt-vanadium alloys might be suitable for permanent magnets. The proportions of iron, cobalt, and vanadium were varied and a range of alloys of particular interest was found, as shown by the indicated area in Fig. I. The limits of this range of composition are 30 to 52 per cent iron, 36 to 62 per cent cobalt, and 4 to 16 per cent vanadium. The compositions indicated by points outside this area were also tested. Preparation and Properties OF Vicalloy I The alloys were usually cast in graphite molds into bars 3/4 in. in diameter and

Jan 1, 1946