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By W. A. Barrows, Carl Zapffe

Jan 1, 1913

By William Daly

THE application of artificial refrigeration, or air-conditioning, to the ventilation of deep, hot mines has long been a subject of interest to the operators of such properties. Artificial cooling of the air in theaters, railroad coaches, and various industrial plants has been so successful within recent years that it has been natural to assume that the adoption of similar methods would afford a ready solution to the difficult problem of mine ventilation. It should however, be obvious, that although there may be nothing technically impossible in the application of this process to mine ventilation there is a great economic distinction between the maintenance of a high standard of comfort for a large number of people in a relatively small space such as a theater and the cooling of air to improve working conditions for miners scattered throughout the extensive workings of a large mine. Many methods of air-conditioning have been considered by the management of the Anaconda Copper Mining Co. at various times, but until the development of the process to be described in this paper none has seemed economically practicable.

Jan 1, 1934

Despite the uncertain political situation in Katanga, copper and cobalt mining and metallurgical operations of Union Miniere du Haut-Katanga were normal at the time of this writing. In fact operations continued normal after Congo independence on June 30, 1960, with copper and zinc production for that year being slightly higher than in 1959. United Nations military operations from September to December 1961 resulted in death, shutdowns and damage to company persons and installations. Nevertheless, results for that year were only slightly off normal production. Moise Tshombe delared Katanga a separate state after Congo independence. Although there has been tribal unrest, the new State has enjoyed relative calm and normal industry by comparison with other parts of the Congo as a result of the firm hand of Moise Tshombe's government and the continued presence of Belgian officials and technicians.

Jan 12, 1962

By VILLIAN 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 correctness 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 c costumbres 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 the costumbres del pais shall not be over-ridden roughshod. He should also insist upon the gradual and reasonable adjustment of these conditions to the exigencies of the work; and (by no means the least difficult of his tasks) he should select the most competent men to patiently direct and teach the natives in the several departments, and by their own example encourage self-respect and decency. While the Braden mine is by no means as yet operated on a large scale, according to modern rating, it will nevertheless be interesting to note what has actually been accomplished there. An illustrative description of the mines and mill of the\

Oct 1, 1909

By John Blatchford, H. O. Hofman

The leading antimony mineral is stibnite. In smelting stibnite ore two processes are available, precipitation and roasting-reduction. The former is suited only for high-grade ores. As low-grade ores are more common than high-grade, roasting-reduction is of greater importance than precipitation. In the roasting process the aim may be to leave the oxidized antimony in the ore, or it may be to volatilize as much of the antimony as possible, collect the volatilized oxide as a rich intermediary product and smelt it for antimony, leaving the gangue poor enough to be considered a waste product. Whichever way the roast is conducted certain difficulties inherent in stibnite are encountered. These are: 1. The low melting point of stibnite which, according to Pélabon,' is 550°C., according to Wagemann2 540°C., and according to Borgstroma 546°C. 2. The ignition temperature: According to Friedrich,4 stibnite, if heated in air, begins to oxidize at 290°C. if the size of a grain is 0.1 mm. in diameter; at 343", if 0.1 to 0.2 mm.; and 430" if 0.2 mm. 3. The fusibility of a mixture of Sb2S33 and Sb203 which in the form of kermesite (Sb2S3)z.Sbz03 melts at 517°C.6 4. The volatility of Sb2Ss and SbzOs, for which no numerical data appear to exist, although practical experience has shown that they are volatile at low temperatures. As regards the oxidation of metallic antimony, we have the experimental evidence of C. F. Plattner6 that when fused and brought to a red heat, it burns with a bluish-white flame to Sb2Oa which passes off as a

Jan 1, 1916

By R. E. Cuthbertson

AN early appreciation by the management that Climax ore presented a challenging problem of economic concentration was responsible for the establishment, in June 1926, of an ore-testing department at the experimental plant of the Colorado School of Mines at Golden, some ninety miles from Climax. An engineering office was later organized in the same community for the design of all ore-treatment units erected at Climax during the period of rapid growth. Work of the ore-testing and design staffs was effectively co-ordinated under a common head. The primary reason for having the ore-testing and plant design departments in Golden, was to place these activities under the able supervision of A. J. Weinig, consultant for the Climax Molybdenum Co., and director of the experimental plant. A secondary consideration was the availability of excellent facilities for research in ore dressing in a highly favorable environment. Concentration of molybdenite by flotation from an ore of simple mineral composition does not appear, superficially, to present a serious problem in ore dressing but experience belies this apparent simplicity. The molybdenite content of average Climax ore is low and it is finely

Jan 1, 1946

By T. W. Guy

During the past three years the Surface Preparation Committee of the American Mining Congress Coal Operators' Committees has been collecting data on dewatering and drying washed coal, and on screening coal in representative plants in the Eastern and Central bituminous fields. Because of wide variations in bed moisture, such data can be compared only after deducting the bed moisture. It was found that practically every company used a different routine for moisture sampling and determinations. Some reported the moistures as total moistures, others as surface moistures, air-dried moistures, or oven-dried moistures. For most of the reports it was necessary to estimate, from a consideration of the bed moisture and other data available in a given case, corrections to be made in order to obtain surface-moisture figures as a common basis for comparison. At any plant, and regardless of bed moisture, the percentage of surface moisture remaining in a product when the dewatering, or a given stage of the dewatering, has been completed, is the real measure of what has been accomplished. The descriptions and data given with Fig. 1 show that surface-moisture figures show relationships that would not be shown by total moistures. Therefore bed moisture should be deducted, or, if more practicable, the surface moisture of the products should be measured direct. A preparation engineer finds one per cent, or even a part of one per cent, of surface moisture a very important consideration in the results of his efforts to find the most effective and economical methods of reducing and controlling the surface moisture in his products within the required limits. Therefore it is important for him to have accurate measurements of surface moisture with minimum uncertainty as to whether they sometimes include less than the surface moisture and at others all of the surface moisture plus an unknown part of the bed moisture. The Problem We know that pieces of coal have a capacity for holding water: (1) inside themselves, which is a natural characteristic of the bed from

Jan 1, 1938

By T. W. Guy

During the past three years the Surface Preparation Committee of the American Mining Congress Coal Operators' Committees has been collecting data on dewatering and drying washed coal, and on screening coal in representative plants in the Eastern and Central bituminous fields. Because of wide variations in bed moisture, such data can be compared only after deducting the bed moisture. It was found that practically every company used a different routine for moisture sampling and determinations. Some reported the moistures as total moistures, others as surface moistures, air-dried moistures, or oven-dried moistures. For most of the reports it was necessary to estimate, from a consideration of the bed moisture and other data available in a given case, corrections to be made in order to obtain surface-moisture figures as a common basis for comparison. At any plant, and regardless of bed moisture, the percentage of surface moisture remaining in a product when the dewatering, or a given stage of the dewatering, has been completed, is the real measure of what has been accomplished. The descriptions and data given with Fig. 1 show that surface-moisture figures show relationships that would not be shown by total moistures. Therefore bed moisture should be deducted, or, if more practicable, the surface moisture of the products should be measured direct. A preparation engineer finds one per cent, or even a part of one per cent, of surface moisture a very important consideration in the results of his efforts to find the most effective and economical methods of reducing and controlling the surface moisture in his products within the required limits. Therefore it is important for him to have accurate measurements of surface moisture with minimum uncertainty as to whether they sometimes include less than the surface moisture and at others all of the surface moisture plus an unknown part of the bed moisture. The Problem We know that pieces of coal have a capacity for holding water: (1) inside themselves, which is a natural characteristic of the bed from

Jan 1, 1938

By C. A. Siebert, D. J. Girardi

PRACTICALLY every metallurgical process in-volves, at some stage or another, the contact of a metal with a gas. Because of this, gas-metal re-actions are of great practical importance and have been subjected to numerous investigations. It has long been recognized that the presence of cuprous oxide in liquid copper has an important effect on its casting characteristics and .physical properties. This has led to the desirability of determining the quantitative relationships between cuprous oxide in the liquid copper and the usual gases present during processing. Such data are not only of practical importance but also of a theoretical interest in that they provide a means of applying the principles of physical chemistry to problems in applied metallurgy. The object of this investigation was to determine the quantitative relationship at equilibrium between the gases carbon monoxide and carbon dioxide and the cuprous oxide content of liquid copper. The reaction and its equilibrium constant may be expressed as follows: 2 Cu (liq) + CO2 (g) = Cu2O + CO (g) acu2o X aco/a2 cu X aco2 Here the underlined symbol Cu2O designates cuprous oxide dissolved in liquid copper and (a), the activity of the various constituents. The activities of carbon monoxide and carbon dioxide are assumed to be directly proportional to their re- spective partial pressures and the activities of cuprous oxide and copper are taken to be proportional to their respective mol fractions. The equilibrium constant may then be expressed as follows: K2 = Ncu2o X Pco [Ncu]2 X Pco2 where N = mol fraction The solubility of carbon monoxide and carbon dioxide in liquid copper is a rather controversial subject.'-' A review of the literature is given by 0. W. Ellis.' It appears that carbon monoxide and carbon dioxide are both only very slightly, if at all, soluble in liquid copper. Volskii and Slobodskoi5 determined the equilibrium between carbon monoxide, carbon dioxide, and liquid copper at 1100°C. Their results show a higher cuprous oxide content for a given CO/CO2 ratio than found in the present work. The system hydrogen, water vapor, and liquid copper was investigated by Allen and Hewitt8 over the temperature range of 1090" to 1350°C. Equilibrium values for the system carbon monoxide, carbon dioxide, and liquid copper calculated from these data agree reasonably well with the present work. Materials and Procedure The copper used was oxygen free, designated as OF and analyzed as 99.98 pct copper with no appreciable amount of any one impurity based upon spectrographic determinations. The carbon dioxide was cylinder gas averaging about 99.95 pct CO2 with air as the major impurity. The carbon monoxide was produced by passing carbon dioxide over heated charcoal. Alundum combustion boats were used as containers for the liquid copper. No appreciable reaction took place between the copper and the alumina. This was evident from the fact that the copper sample after a run did not ordinarily adhere to the bottom of the boat and that the

Jan 1, 1951

William Clinton Brown, Brooklyn, N. Y.: The demand for an apparatus for cooling water for condensers, refrigeratingmachinery and air-compressors, as well as water-jacketed furnaces, has led manufacturers to put such an apparatus on the market, so that it is now possible to purchase a cooling-tower, properly designed and constructed, by simply stating the amount of water to be cooled and the temperatures of the hot and the cold water. The principle is similar to that described by Mr. Henrich, but wood is not used in the best apparatus. There are two great objections to wood: First, it cannot last long under the very trying conditions to which it is subjected; and second, it absorbs the organic matter with which water in constant use becomes impregnated, and the resulting odor is very disagreeable. A few days ago I saw a cooling-tower and condenser, built by the Henry R. Worthington Co., in operation at the Edison electric-lighting station in Brooklyn, N. Y., cooling the water for a 700 horse-power condenser. It consisted of a large stack of iron, about 15 feet in diameter by about 30 feet high. This stack was filled with tiling through which the water falls. A whirligig distributes the water evenly over the top, and a large fan, about 6 feet in diameter, driven by a 10 horse-power electric motor, blows air into the bottom, thus giving a positive circulation. The water, in running down the sides of the tiling, is met by the blast of air, and enough is evaporated to cool the rest. The vacuum-gauge on the condenser showed 26 inches; so the condenser was undoubtedly getting sufficient cool water.

Jan 1, 1896

By E. S. Tankins, G. R. Belton

A simple solution model, based upon the formation of molecular species, is developed for strongly electronegative dilute solutes in liquid binary-metallic solvents. Two approximations are considered for the relative concentrations of the species: the random and the quasi-chemical. Equations are presented for the partial molar free energy, enthalpy, and entropy of mixing of the solute. An experimental study has been made of equilibrium in the reaction H2 6) +0 (dissolved) = H2O(g))for the liquid Cu-Co alloys. The standard free energy of solution of oxygen is presented as a function of composition for the alloys at 1550°C and as a function of temperature for five of the alloys. The experimental results for these alloys and also for Cu-Ni alloys are shown to be in reasonable agreernent with the theory in the random approximation. A knowledge of the thermodynamic behavior of dilute solutes in liquid metals and alloys is of importance in understanding and designing refining and alloy-making processes. Accordingly, several attempts have been made to derive suitable solution models to forecast the effect of a third component on the activity coefficient of such a solute in a metal. Alcock and Richardson' reviewed the literature prior to 1958 and also showed that a regular solution model gave a reasonable description in the case of metallic solutes but failed to account for the behavior of the more electronegative solutes sulfur and oxygen. These same authors2 later modified their model by using the quasi-chemical approximation3 to calculate the average composition of the first coordination shell surrounding each solute atom. This modified model was shown to lead to a better qualitative description of the behavior of the electronegative solutes; however, quantitative agreement with experimental data for oxygen in alloys could only be achieved by assuming a very small coordination number. The authors concluded that the major source of error in the model was the assumption that pairwise interaction energies were independent of composition. Substitutional and interstitial random solution models by Wada and saito4 are essentially similar to the first model except that the required interchange energies were derived from the modified solubility parameter equation of Mott, instead of from experimental binary data. Most recently Hoch5 has presented a statistical model for interstitial solutions and has applied the model to the Fe-C-O system. However, as the various interaction energies needed in the model had to be derived from the ternary data, the model does not promise well as a means of forecasting ternary behavior. Each of the above models carries the assumption that the strongly electronegative solutes have the same configurational environment as metallic solutes; i.e., the solute can be treated as a substitutional or interstitial atom in a quasi-crystalline lattice and is surrounded by a normal coordination shell of solvent atoms. There are, however, a number of facts which suggest that this is unlikely. First, the heats of solution are large, being more typical of molecule formation rather than alloying. For example, the heats of solution of monatomic oxygen and sulfur in liquid iron are -90 kea16,8 and -74 kea1,7, 8 respectively. These are to be compared with maximum heats of solution of metallic solutes in liquid iron of about -13 keal (silicon is an exception with -28.5 kea17). The large depression of the surface tension of liquid iron by trace amounts of the electronegative solutes oxygen, sulfur, and selenium9 suggests, by analogy with aqueous systems, the possible existence of polar molecules in the liquid. The effect of these solutes is at least three orders of magnitude greater than normal metal solutes.10 As has been pointed out by Richardson,11 the electron affinities and ionization potentials of oxygen and sulfur are such that it is likely that they exist in metallic solution as negatively charged ions. If this is so, and it is assumed that electrostatic forces play an important role in determining the configuration, it is unlikely that the stable configuration will be that of an isolated ion surrounded by a symmetrical coordination shell of solvent ions. It is more likely that the energy of the system would be lowered by the formation of solute-solvent screened dipoles. The above arguments suggest the formation of "molecular species" between solute and solvent atoms. The idea of the existence of molecular species in such solutions is not new, however', for Marshall and chipman12 have explained in a semi-quantitative manner the C-O equilibrium in liquid iron by postulating the species CO. Chen and Chip-man13 interpreted their measurements on the Cr-O equilibrium in iron in terms of the species CrO. Zapffe and sims14 have also postulated the existence of such species in liquid-iron alloys.

Jan 1, 1965

By K. M. Rolls, F. W. Reuter, J. Wulff

The superconducting behavior and microstructural characteristics of a nominal Nb-40 wt pct Ti-0.239 wt pct O alloy were studied as a function of ther mo -mechanical processing treatment. Critical current density us applied transverse magnetic field was obtained for 0.010-in.-diam wires at 4.2°Kin steady fields 14 to 110 kG. Both optical metallogvaphy and transmission electron microscopy were used to delineate the micros tructures of the same wires. It wan found that a 1-hr 500°C precipitation heat treatment after cold drawing to final size led to the highest critical current density. Heat treatment at 600°C also led to a high critical current density, but the precipitate differs in kind and form from that at 500°C. The resistire critical field was also found to be sensitive to precipitation heat treatment since the effective composition of the superconducting phase changes. This is discussed in terms of the oxygen in interstitial solid solution. Two types of high-field superconducting wire are at present used in the construction of high-field superconducting solenoids. These types are solid-solution alloy wire such as Nb-Zr and Nb-Ti and composites of the brittle inter metallic compound Nb3Sn. The latter generally have a high super cur rent-carry ing capacity which is difficult to vary if properly made. The supercur rent- carry ing capacity of the former can be varied drastically and often predictably by suitable thermomechanical processing treatments. In general, the critical current density Jc of the solid-solution type of alloy is increased by cold work and by additions of interstitial elements along with aging heat treatments. The imperfections which result are be-iieved to be responsible for the observed increase in Jc. In 1962 Kneip and coworkers1 found that the critical faurrent density of Nb-Zr alloys could be increased by proper heat treatment preceded and followed by cold work. Betterton and coworkers2 using a Nb-25 at. pct Zr alloy found that small additions of oxygen or carbon enhanced the effect of this heat treatment. They suggested that the interstitials present aided precipitation in the alloy, leading to a filamentary structure with superior properties. If the precipitation heat treatment was omitted, interstitial additions had a negligible effect on Jc. wong3 showed that higher heat-treatment temperatures lowered Jc. Walker and co-workers,4 who studied microstructure (by transmission electron microscopy) as well as superconductivity, found that the Jc anisotropy introduced by cold rolling was itself affected by heat treatment. They were unable to clarify the relation between microstructure and critical current density, although evidence of precipitation was indicated. More recent investigation of Nb-Zr alloys,5,6 besides showing that structural defects and fiber ing due to cold work and precipitation serve to raise Jc, also elucidate important optically observable microstructural changes which occur upon precipitation. In these reports, coarsening of the microstructural features was found to decrease Jc. Vetrano and Boom,7 who studied Ti-20.7 at. pct Nb, found that Jc was increased to a maximum by a 415°C, 3-hr heat treatment following quenching from 800°C and cold working. Heat treatments can also affect the resistive critical field Hr. Final-size heat treatments of Nb-Zr wire can lower Hr drastically if gross phase decomposition occurs5'* or moderately if the effects of cold work are eliminated without changing significantly the composition of the phase of interest.3,5,6,8 The percentage of oxygen which can be added to Nb-Zr alloys to enhance Jc is limited by the difficulty of subsequent cold drawing. Since Nb-Ti and Ta-Ti alloys in contrast can tolerate appreciably higher percentages of oxygen, it was decided to investigate the superconducting behavior of various alloys in these systems. The present paper describes the results of adding oxygen to a nominal 40 wt pct Nb alloy as a function of thermomechanical treatment. I) EXPERIMENTAL PROCEDURE A small alloy ingot was prepared from high-purity niobium, iodide, crystal-bar titanium, and Nb2O5 powder by arc melting on a water-cooled copper hearth in a gettered argon atmosphere. The ingot was turned and remelted fourteen times to insure homogeneity. After final melting and rapid cooling, it was machined round to 0.415 in. diam, jacketed in stainless steel, and cold-swaged to 0.117 in. diam. The jacket was removed and swaging continued to 0.051 in. diam followed by wire drawing in carbide dies to 0.010 in. diam. Although it was intended that about 1500 ppm O (by weight) be added, inert gas fusion analysis indicated a 2390 ppm 0 content, apparently due to additional oxygen pickup in the arc furnace. Even so, the alloy was sufficiently ductile to be cold-worked to greater than 99.9 pct reduction

Jan 1, 1967

By B. S. Butler

A. D. Mutch (Falconbridge Nickel Mines Ltd., Ona-ping, Ontario)—This contribution is prompted by the fact that the writer has recently published an article'!' which has in part the same general conclusions as B. S. Butler's, namely, the form of the standard mineral paragenesis in hypogene deposits and the parallel transition from early high temperature acid to late low temperature alkaline or neutral solutions. Since the writer also recognizes that he is not fully qualified to discuss the formation of ore deposits as a chemical problem, this discussion will be limited to summarizing other observations and will suggest how Butler's Table II might be made more effective. The form of Butler's table is not unlike that widely used by European geologists'" in which the various minerals are related to the types of ore fluids—peg-matitic, pneumatolic and hydrothermal. Thus the decrease in temperature and change in pH of the ore-bearing fluids as recognized by Butler may also be paralleled by perhaps even greater changes in composition, density, and character. W. H. Newhouse's article:" on the sequence of hypo-gene ore mineral deposition is still one of the most complete analyses of the problem. In it he makes four major observations: 1) The order of O, S, As, Sb is the same as their increasing atomic weights and the same as their melting points. 2) The order of the metallic elements is the same as the Schuermann series. 3) The general mineralogical order is paralleled by decreasing heats of formation. 4) The order is generally in decreasing hardness, higher metal content, and higher specific gravity. The order of 0, S, As, and Bi is also the same as their relative abundance. Another point worth mentioning about this series is that As, Sb, Bi, when abundant, often substitute for sulfur in the early pyrite-like minerals, whereas later in the sequence these elements appear to act more like metals. This behavior may be a further indication of the acid character of the early fluids. C. J. Sullivan"' has attempted to show that the sequence of the metallic elements is related to the order of their melting points and has discussed the interrelationship of the different types of bonding of sulfo-phile and oxiphile elements in minerals. Items 3 and 4 might best be summarized by saying that bonding of the minerals in the series appears to be from ionic to covalent to metallic, the early minerals being light in weight, hard, and near-transparent; the intermediate minerals of intermediate weight, semi-transparent, and semi-conducting; and the end minerals heavy, soft, and malleable, opaque and good conductors. A rapid fall in temperature has been assumed to be the cause of ore deposition in many deposits. Perhaps this in turn is the effect of a rapid release of energy in the form of pressure release and change of volume, the first minerals to form being those with the highest heats of formation which absorb the released energy the most rapidly. Butler's Table II could probably be streamlined and made more effective if the listed compounds were assembled as mineralogical groups as in Dana. Thus the sulfides, arsenides, antimonides, bismuthides, and sulfa salts could be arranged in AX,, AX, A2X2, etc. groups. Since these are continuous substitution series, in which the fields of stability and the heats of formation of the various individual minerals can be fairly regarded as similar, this should be accomplished with no loss of clarity. The occurrence of the individual minerals and the precise sequence of the mineral deposition in any one deposit is probably more dependent on the concentration and relative abundance of the component elements. The assembling of geological data in tabular form such as Butler's Table II will continue to be a very effective method of studying geological phenomena. The importance of this particular problem has been pointed out by C. F. Park,% who concludes that understanding of mechanisms of the standard paragenesis and interrelated problems of mineral zoning in space and time is one of the major keys to classification of ore deposits.

Jan 1, 1959

By John Jermain Porter

The chief purpose of this paper is to indicate the laws governing the fuel-economy of the cupola, to examine the feasibility of some of the proposals for increasing its fuel-economy, and to show that the conditions limiting fuel-economy here are altogether different from those prevailing in the blast-furnace. The two methods available for studying the thermal efficiency of the cupola and determining the factors limiting fuel-economy are: 1, by the determination of the total heat-balance; and 2, by the application of the theory of critical temperatures. The case selected as an example represents a cupola operating under fairly efficient conditions. The data are as follows : Cupola, GO in. in diameter, 15 ft. high to the charging-door, with a 9-in. lining. Bed-charge, 2,000 lb. of coke and 4,000 lb. of iron. Subsequent charges, 400 lb. of coke and 4,000 Ib. of iron. Total number of charges, 20. There was 800 lb. of coke recovered from the drop, hence the total coke burned is 8,800 lb., or 0.11 lb. of coke per Ib. of iron. Coke contains 90 per cent. of fixed carbon and 2 per cent. of moisture. 300 1b. of kindling-wood is used in lighting. 80 lb. of limestone (95 per cent. of CaCO,) is used per charge, or 0.02 lb. per Ib. of iron. Melting-loss, 4 per cent.; distributed thus : Fe, 3.5; Si, 0.25; Mn, 0.25 per cent. Average analysis of top-gases : CO2, 15.1; CO, 10.0 per cent. Average temperature of top-gases, 1,600" F. Temperature of air and stock charged, 60" F. Dew-point of air, 50 F. The items entering into the total heat-balance and their calculation are as follows: 1. Heat of combustion of fuel.—Total heat evolved = 14,580 x lb. of carbon burned + 7,200 X Ib. of wood burned. Hence B.t.u. per lb. of iron charged =

Jan 1, 1913

By CARLE R. HAYWARDC

BEFORE discussing this subject it is necessary to define somewhat the meaning of the tern metallurgical.. When I was a student at M. I. T. ore-dressing was not thought of as metallurgy in any sense of the word, but it was considered as more closely allied to mining, enabling the miner to market an otherwise unmarketable product, or at least to market it to better advantage. Progress in ore-dressing has gradually allied it more closely with smelting, for at present the raw material received by the smelter is predominantly concentrates and smelting practice has been profoundly affected by the products of the concentrating mill. It is not surprising therefore that in many schools ore-dressing is frankly considered as metallurgy and although there may be some dissenting opinions it will be considered as such in this discussion. Twenty-five years ago at M. I. T. metallography was taught in a few optional lectures. This subject has developed rapidly and been expanded into the new and increasingly important field of physical metallurgy. To many metallurgists the -term metallurgy means only physical metallurgy. They know little or nothing about smelting and leaching and even less about ore-dressing. Having then broadened the scope of the term metal¬lurgy to cover ore-dressing, smelting, leaching and phys-

Jan 1, 1930

By DR. SAMUEL B. CHRISTY

? THE man is always greater than his work.? The training of the men who are to develop the mineral resources of the world is the most important problem connected with mining engineering. It becomes ever more important to civilization as the mineral wealth of the earth approaches exhaustion. I have therefore decided to consider a few of the more important problems arising in the training of the mining engineer, and especially those arising in America. THE PECULIAR NATURE OF MINERAL WEALTH. Mining and Agriculture are the two fundamental arts. Without the latter our existence would be precarious; without the former, our civilization impossible. Agriculture furnishes that regular supply of food and raiment which leads to the growth of large communities in which cultivated leisure first becomes possible; while raining furnishes the metallic thread from which is woven that complex fabric we call civilization. But in these two arts the conditions for success are widely different. Most of the crops that the farmer reaps may be harvested year after year, and the proper fertilizers being added, he may continue the annual harvest indefinitely, while, as a result of cultivation, his farm becomes yearly more valuable. But the crop the miner reaps can be harvested but once in the history of the race. Our mineral wealth has taken unknown ages to mature in the bosom of the earth. The ripened fruit can be plucked but once. There are no fertilizers for worked out mines. It never pays to work over a mine that has been

Sep 1, 1905

By W. O. Philbrook

An engineering analysis indicates that the coke rate in present blast-furnace practice is set not by chemical or thermal needs but to give adequate charge permeability for economical driving rates. An equation showing interrelations among pressure drop, gas flow, and charge characteristics has been derived. Flooding conditions and the location of the fusion zone are discussed. Maximum ore size is probably limited by chemical re-ducibility rather than by heat transfer. THE intention of this paper is to show that the ].imitations on the production rate and coke requirement of the iron blast furnace are not primarily chemical or thermal in nature but are related to characteristics of the burden and operation that govern gas flow, heat transfer, and stock movement. A semiquantitative analysis will be developed in terms of standard engineering principles to give a useful picture of the relative importance of physical and mechanical factors in contrast with the chemical features of the process that are more commonly emphasized. Most of the details of calculation have been omitted in the interest of brevity and to avoid submerging the rnain points in a sea of arithmetic. Numerical values have been arrived at by objective methods from reported operating data or by reasonable estimates of material properties where exact data are lacking and then tested to see how well they fit practice, rather than by working backward to find what assumptions are needed to give the desired answers. The analysis is oversimplified in many ways because exact engineering relations have not yet been studied for bed distributions as complex as are known to exist in the blast-furnace stock column. One objective of this paper is to show that the blast furnace, in spite of its complexity, can be at- tacked by engineering methods in the hope that this viewpoint will stimulate the kind of research needed for a more exact treatment. The basic ideas and many of the conclusions presented are qualitatively well known. A careful literature survey to credit the source of all observations not original to the author would indeed be voluminous, and such has not been attempted. T. L. Joseph's Howe Memorial Lecture' gives an excellent background of what is known about the internal workings of a blast furnace. Other important reference works or sources of specific information will be noted. It is hoped that the present paper will contribute something new, in method of attack and interpretation, that will aid in a clearer understanding of how to operate the blast furnace to best advantage. Factors Limiting Production and Coke Rates The rate of combustion of coke in a blast furnace, as in any fuel bed, is exactly proportional to the rate at which air is supplied. It is axiomatic, then, that the production rate of a furnace is limited by the rate at which it will take wind, i.e., burn coke, and the amount of coke that must be burned at the tuyeres to make a ton of iron of suitable composition. These two possible limiting factors will be considered briefly in the order mentioned. One common restriction on wind rate is flue-dust production. Since the volume of top gas is nearly proportional to the blast volume (by a factor of about 1.35 on a dry basis), an increased wind rate causes a correspondingly increased linear velocity of top gas in the throat of the furnace. The higher

Jan 1, 1955

By AIME AIME

MOST recently elected to the limited group of Honorary Members in the A.I.M.E. is the distinguished Australian metallurgist, Guillaume Daniel Delprat. His citation reads: "in recognition of his distinguished achievement as metallurgist, engineer, and administrator in the production of ferrous and nonferrous metals," Mr. Delprat's ability and experience in both the ferrous and nonferrous fields at once distinguishes him from most of his professional brothers. Mr. Delprat's nativity was neither Australian nor English, for he was born in Delft, Holland, in 1856, and educated in Amsterdam. At the age of 22 he went to Spain, as metallurgist for the Tharsis Sulphur and Copper Co., Ltd. Afterwards he spent some time with the Bede Metal and Chemical Co., which had mines in both Spain and Norway, and of which company he became general manager. Other positions of responsibility held by Mr. Delprat before he went to Australia included the managing directorship of the Cordova Exploration Co., with properties in Spain and Canada; of the Rincon Silver-Lead Mining Co., in Spain; and of the Deloro Gold Mines, in Canada.

Jan 1, 1936

Discussion of the paper of G. K. Burgess and J. J. Crowe, presented at the New York Meeting, October, 1913, and printed in Bulletin No. 82, October, 1913, pp. 2537 to 2591. HENRY M. Howe, New York, N. Y. :-I think we can hardly rate the importance of the entry of the Bureau of Standards into our field. There is no body in the world that is better fitted to undertake this work than that Bureau, and it is work which really calls for the aid of some national organization. The skill and care with which this work has been done speaks for itself. It is very striking that within a very few months the distinguished English investigator, Professor Carpenter, of whom I spoke before, thought that he had disproved the existence of beta iron by proving that the A2 retardation which Professor Burgess has now demonstrated did not occur. Dr. Burgess's demonstration of the existence of. this retardation makes the existence of beta iron very probable, in my opinion. Osmond used to call beta iron " decipuum." You knew of its existence as you know of the existence of certain planets, only by the perturbation which it caused. Certain phenomena could not be explained, except by assuming the existence of a third allotropic form, beta iron. The evidence that you got was always evasive and susceptible of other explanations, except that which we have to-day, which it seems to me is not capable of other explanation. Professor Carpenter proceeded in the same way that Dr. Burgess has, by taking the heating and cooling curves of exceedingly pure iron, and thought that he had shown that there was no thermal change, no absorption or evolution of heat at the supposed A2 point, and hence that the A2 point did not exist. This he did by a piece of reasoning which I think seems to most of us rather surprising. That is to say, if of ten witnesses, three have seen a thing and seven have not, the evidence of the seven who have not is set aside, and that of the three who have seen stands. In Dr. Carpenter's own experiments under certain conditions he found the A2 change, the heat evolution., under certain others he did not. That is like the three witnesses who saw and the seven who did not see. You can arrange your test so that this change will not become visible or so that it is masked. But though an existent change can be masked a non-existent one cannot be shown. So that the reasoning seemed to me wholly fallacious.

Jan 12, 1913

By Henry F. Hebley

INTRODUCTION How often has the thoughtful observer pondered the apparent contradictions experienced in the weather? One can take records of two days, one in the winter and one in the summer. The "degree days" indicate that space heating and domestic load were present in one case and not in the other. The Business Index may be about the same, indicating that the industrial activity of the area and its concomitant use of fuel were about the same. Thus the volume of the products of combustion released to the atmosphere varied only as related to the space heating demand. Yet on one day in winter the atmosphere may be clear and bracing, while on a summer's day the air is thick and murky and the visibility sharply reduced. The situation may be reversed. What are some of the factors that contribute to the creation of these conditions? These few notes have been prepared to indicate some of the influences that are exerted on the problem. THE SOURCES OF ATMOSPHERIC POLLUTION The industrial area of Pittsburgh, Pa., has been a dominant center for the production of iron and steel for over one hundred years. In fact, with the growth of the numerous auxiliary processes Allegheny County which contains Pittsburgh is probably the most industrialized county in the world. In addition, the type of manufacture carried out in this area is predominant dependent on thermal energy (heat). That energy is supplied from coke and coal produced in the vicinity of Pittsburgh. Indicative of the stupendous quantities of fuel that are employed in this industrial area's economy, the following (Table No. taken from the U. S. Census (1940) may I of interest. An influence that has never been fully appreciated by many individuals is the fact that no matter what adventures the gases of combustion experience as they pass through the various processes, ulti¬mately the spent gases are discharged through chimneys to the atmosphere.

Jan 1, 1948