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By P. L. Weston, S. E. Khalafalla

A systematic study was made by the Bureau of Mines on the effect of so me hypothesized accelerators for the process of wustite reduction in carbon monoxide. When small concentrations of promoter materials in the order of 0.69 at. pct were added to the reducible charge, the rate of reduction to iron was increased. Promotion phenomenon prediction was made in light of a suyface reduction mechanism with the aid of Vol'kenshtein's effect regarding the propagation of crystal lattice disturbances by small amounts of relatively larger interstitial ions. The acceleration produced by a typical promotor, such as potassiunl, increases with protnoter concentration up to a maximum, beyond which the reduction rate decreases. Concentration for maximum promotion depends on the nature and physicochemical properties of the promoter. The extent of reduction rate enhancement is found to be directly proportional to the atomic volume and electronic charge of the additive. DESPITE the enormous volume of literature on iron oxide reduction, very little is reported concerning additive or impurity effects on this important metallurgical process. The beneficial effect bf calcium compound additions on the reducibility of iron oxide sinters has been reported by Tigerschiold,1 vor dem Esche,2 and Edstrom. Doi and Kasai~ found that the addition of lime or limestone to iron ores helps to break up any unreducible compounds, such as fayalite or ilmen-ite. and thus free the combined iron for reduction. Schenck et al. 5 suggested that the increased reduction rate obtained when adding lime could be accounted for by the instability of wustite in the presence of lime. Acid-base slagging reactions resulted in wustite disproportionation according to The dicalcium ferrite formed will yield iron and calcium oxide during reduction. Regenerated calcium oxide dissociates more wustite. This mechanism has been used by Seths and white7 to explain their experimental results. Recently, Strangway and ROSS' attributed the calcium carbonate acceleration of iron oxide agglomerate reduction to increased porosity, both initial as well as that developed during reduction. Aside from calcium carbonate, or oxide, no other promoter was noted in the literature, except for a brief mention by Barrett and woodg on the effect of sodium carbonate and aluminate as activators for the hydrogen reduction of magnetite at 600°C. The present investigation systematically studied a host of other promoters, including calcium and sodium, in an attempt to elucidate the mechanism by which promotion takes place and to fit the results into a simple chemical model. To attain this goal, the effect of promoter physical properties, such as atomic volume, electronic charge, and concentration are related to wustite reduction kinetics in this paper. Wustite reduction to iron, rather than the overall hematite reduction, was chosen since this reaction is known to be the slowest, and hence the rate-deter mining step for the overall iron oxide reduction process. EXPERIMENTAL PROCEDURE Raw Materials and Their Preparation. The pure or impregnated wustite pellets were prepared from minus 400-mesh chemically pure hematite powders. A known weight of hematite was thoroughly and uniformly mixed with a calculated weight of the additive. The mixed paste containing 35 wt pct water was gradually heated from 400" to 1200° C and fired at 1200°C for approximately 4 hr in an air atmosphere. After cooling, the sinter was pulverized to minus 100 mesh and pelletized into minus 4- plus 5-mesh spheres. Pellets were fired, similarly to the paste mix, air-cooled, sized, and stored. An appropriate weight of the charge (20 g) was placed in a zirconia reduction tube maintaining a uniform oxide bed height of 1 cm and a cross section of 7.1 sq cm for all of the test runs. The samples were supported in the vertical reaction tube by a bed of fragmented insulating firebrick plus 3- to 6-mesh alumina beads. The hematite was then transformed to wustite by reduction with a 30 pct CO2-70 pct CO gas mixture at 1000°C in a globar furnace. Complete conversion to wustite was ascertained by a continuous infrared gas analyzer recording the CO-CO2 content of the effluent gas until no carbon monoxide was absorbed from the inlet gas, and inlet-outlet gas analysis remained constant for 30 min. The wustite sample was then reduced with 100 pct CO at 100WC. From the recorded data, an initial rate of reduction was determined by the initial slope of the graph percent reduction vs time. In order to estimate the accuracy of the data, five separate determinations of the reduction curve of pure wustite, under otherwise identical conditions, were performed. The maximum deviation from the average reduction at 14 min amounted to 2 2 pct reduction. This deviation corresponds to 3.8 pct variation based on the percent reduction of the sample. Aiiy impurity effect below the limits of this maximum deviation was considered a spurious result. If the effect exceeded + 4 pct, then it was considered as a positive one. Considerable care was exercised in determining the initial rate from the slope of the initial segments of the curve. Each reduction curve was examined separately on large graph paper and the best tangent to the curve at zero time was drawn. The slope of this tangent was taken as a measure of the initial fractional reduction per minute. Although the time required to reach 50 pct reduction may be of special practical significance, initial rate measurements are invaluable in fundamental studies. These rates provide a measure of the process kinetics on the initial

Jan 1, 1968

By C. Edwin Nighman

THE following is a description of the methods used in rescuing men and extinguishing the underground fire at the Pennsylvania mine, Butte, Mont. This fire, which cost the lives of 21 men, began about 9 p.m., Feb. 14, 1916, at or near a ventilating fan on the 1,200 air-shaft station. This shaft at that time was downcast, while the main hoisting shaft was upcast. Owing to the proximity of the fire to the air shaft, the air in the latter soon became heated, and as the fan on the level was not running¬the power having been cut off shortly after the outbreak' of the fire-the aim' shaft became upcast to the 300 level. At this point a blanket of cold air from the surface caused the smoke and gases to he drawn in on that level and carried down again through the workings to the 1,200. A short time after the discovery of the fire, water was turned down the air shaft through a series of pipes around the collar of the shaft, which caused the smoke to recede, below the 300, so that within 2 hr. it was possible to search that level for the missing men. From the above it will be apparent why the air shaft was upcast instead of downcast as under normal conditions, and why men were suffocated at considerable distances from the seat of the fire. The smoke and gases that came up the main hoisting shaft did not diffuse through the workings to any extent. There are doors on all levels in the connections to the main hoisting and air shafts, but-in the confusion and running around many of these doors were left open, and this undoubtedly caused the smoke and gases to spread more rapidly than they would otherwise have done. It was necessary for most of the men on the various levels to pass close to the air shaft in going to the hoisting shaft, and when they encountered the smoke and gases in that vicinity a number turned hack and climbed down with the direction of the air currents and were then suffocated, while all those who passed through the relatively short pall of smoke to the main shaft were saved.

Jan 2, 1917

By D. E. Moore

The strength of a natural serpentinite gouge was measured at 400°C and an effective pressure of 100 MPa. The strength of the gouge decreased with increasing pore pressure to 50 MPa and then was nearly constant between 50 and 125 MPa. The samples at 50-125 MPa pore pressure slid stably, whereas those at 3-25 MPa pore pressure showed stick-slip behavior. Lengthening the pre-heating time to 72,000 s of samples at 100 MPa pore pressure led to increases in both the strength and the likelihood of sliding unstably. With still longer pre-heating times, the strengths decreased again and sliding once more became stable. The strength of the gouge at 3 MPa pore pressure was unaffected by changes in pre-heating time. A possible explanation for the results is that excess pore pressures are being generated in the gouge, causing the true effective pressure to be lower than the apparent value.

Jan 1, 1984

By AIME AIME

THOUGH the dust-control systems in the crushing plants and other buildings at Morenci do not differ materially from similar installations in other large copper reduction works, it is probable that in few other plants has as much attention been paid to the dust problem. Possibly the most striking feature of the Morenci installation is the manner in which the necessary equipment has been built into the various structures, and the absence of unsightly pipes, ducts, and fan houses. That this result has been attained is due, in no small part, to the basic conception that the control of the dust in a milling plant should be an essential part of the process itself and not something to be tacked on later after the plant is in operation. The control systems were designed and developed along with the general plant construction program and when the first car of ore was dumped into the crusher the dust-control equipment was ready.

Jan 1, 1942

By R. Dawson Hall

WHAT are the opportunities for the services of engineers in the coal mines? The best answer perhaps can be made by detailing the present lines of development in the bituminous coal mining regions. They are just at the beginning of a period that can be conservatively termed revolutionary. A few glimpses of new possibilities in economic mining that will reduce the cost of bituminous coal at the mines by at least one half have convinced almost everyone that a change must shortly come about. The cost of housing has become such a burden, especially in mountainous regions, that development which demands the hiring of more men and constructing more houses would not be profitable. The introduction of mechanical aids to mining, transportation and dumping suggests a way of obtaining a large tonnage with the same or a smaller number of men with no further house construction. At the same time the restriction of immigration has made it increasingly difficult to obtain men inured to hard labor. Modern civilization is not productive of muscular energy and at the same time it provides men who are not indisposed to the use of the mental effort required to direct the physical forces now available for the replacement of such energy.

Jan 1, 1924

By B. F. Decker, D. Harker

The recrystallization reaction in OFHC and spectroscopically pure copper has been followed by X ray diffraction determinations of the amount of material with the cold-worked and recrystallized textures in specimens which had been given various heat treatments. The heats of activation for recrystallization are found to be: 29.9 kcal per rnol for OFHC copper and 22.4 kcal per rnol for spectroscopic copper. A reliable and speedy method for measuring the amount of recrystallized material in a piece of rolled metal, together with a new scheme for low temperature heat treatment, have made possible a determination of the activation energy for recrystallization in rolled copper. This method for studying recrystallization rates is different from others reported in the literature.' Oxygen free, high conductivity copper—OFHC copper—of purity 99.98 pct gave an activation energy for recrystallization of 29.9 kcal per mol with recrystallization data taken in the temperature range 208-245°C. Copper of purity 99.999 pct from the American Smelting & Refining Co. gave an activation energy for recrystallization of 22.4 kcal per mol with recrystallization data taken in the temperature range 43-135°C. The great change in activation energy for recrystallization as the small amount of impurity in the metal is decreased suggests that the motion of grain boundaries is conditioned by the impurities which must be concentrated in them. Thus the OFHC copper recrystallizes with an activation energy of the order of magnitude to be expected for the diffusion of the kind of impurities likely to be present. The high purity copper, on the other hand, recrystallizes with a much lower activation energy, in accord with the notion that the grain boundaries need not wait for the impurities to diffuse with them. Copper when strongly cold-rolled has a well-defined crystallite texture which can be described by saying that the [111] direction of the face- centered cubic crystals is aligned approximately in the cross-rolling direction and that faces of the form {110} lie approximately in the rolling plane. When such rolled copper is completely annealed the crystallite texture is quite different: the [loo] direction is in the cross-rolling direction and faces of the form (100) are in the rolling plane. At intermediate stages of annealing, the copper contains both textures. If a Geiger counter X ray diffraction spectrometer is set up so as to measure the intensity of the (200) Bragg reflection from the rolled surface of a piece of copper strip, this intensity increases from a very small value in the cold-worked state to a maximum as the specimen is annealed. The same would be true for (200) reflections from planes normal to the rolling or cross-rolling directions. In view of this fact, the amount of material in the copper which has recrystallized can be measured by comparing the intensities of one of these reflections just mentioned with the intensity from a similar specimen after complete annealing. In much the same way the intensity of (111) reflections from planes normal to the cross-rolling direction could be used to measure the amount of unrecrystallized material in the specimen. In the work to be described here the amounts of recrystallized and unrecrystallized material in partly annealed rolled copper specimens were determined in this way. Experimental Procedure Samples of oxygen free high conductivity (OFHC) copper, cold-rolled 99.7 pct to 0.002 in. thickness, were subjected to heat treatments for various chosen times at four different temperatures, and high purity copper samples, cold-rolled 98.0 pct to 0.0015 in. thickness, at six different temperatures. Each sample, after treatment, was placed in an orientation sample holder for use with a Geiger counter X ray spectrometer and a reading was taken of the intensity of the (200) reflection from planes perpendicular to

Jan 1, 1951

By S. T. Wellman

The gradual change within the Iast few years from wrought-iron to steel for many purposes, notably for rails, plates, beams and other structural shapes, has brought the desirability and possibility of casting and rolling the steel in very large masses as compared with the

Jan 1, 1891

By Walter Loel

THE application of aerial photographs to all phases of geologic mapping is set forth, indicating the advantages to be gained in different types of country and under varying climatic conditions. Methods of field and office procedure are given from a geological point of view, as well as suggestions regarding the best methods of aerial mapping for different uses and under varying field conditions, including the study of submarine geology. Aerial photographs with accompanying geologic maps are shown to illustrate the appearance from the air of different geologic features under varying climatic and topographic conditions.

Jan 1, 1938

By Irving Palmer

DURING the past 15 years in this country there have been few additions to the literature of lead smelting. After the consolidation of the principal smelting companies at the beginning of this period it became the policy of the larger company not to permit the publication of details in regard to many of its metallurgical processes. This led to similar action on the part of some of its competitors. The result, of course, was a decided decrease in the number of papers written upon the practical side of the subject. Even upon the theoretical side the contributions have been few. It would seem that the industry as a whole has suffered from this general unwillingness to exchange information. While it is true that a given company is entitled to the reward that may come from its own development of a new process, it is also true that a still greater reward might be the result of a free exchange of ideas with other plants. This principle has been recognized for a long time in other metallurgical industries, notably those engaged in the smelting of iron and the manufacture of steel. It is pleasing to note that the leading lead-smelting company has very recently decided to modify its policy of secrecy, and to permit the publication of papers covering some details of its metallurgical methods. The statement has been made that there has been but little progress in lead smelting during the period just referred to. This impression is due in part to the scarcity of papers written on the subject. There has been, it is true, some discussion of the new sintering processes, but with little reference to detail, and to the effect that blast roasting has had upon the industry as a whole. In spite of the prevailing belief, it may be said that lead smelting, in common with other metallurgical industries, has made steady and substantial progress. It is the purpose of the present paper to discuss briefly some features of the industry as it is now conducted, with special reference to the blast-furnace practice in the larger silver-lead smelting plants of the United States and Mexico.

Jan 7, 1914

By John G. Baragwanath

THE September issue of the Engineering and Mining Journal carried an item regarding the Cercapuquio Mining Co. which was mentioned as a large producer of lead, zinc, and cadmium, situated near Huancayo, Peru. The paragraph caught my eye because I had not heard of the property in thirty years and I recollect all too well the circumstances of its accouchement. In 1916 1 was making my headquarters in the town of Huancayo, then the terminus of the Central Railway of Peru, and was examining mines and prospects in that general area for Cerro de Pasco. In the course of my work I became acquainted with an engaging and energetic "practical" miner named Balarin, a Dalmatian living in Huan¬cayo, and made numerous trips in his excellent company. One day Balarin came to the down-at-heels hostelry where I stopped and told me that a Cholo prospector, a character by the name of Jose, had just reached town and claimed to have made a discovery in a little known locality called Cercapuquio. Lead-silver, Balarin said, and showed me a sample of galena about the size of his fist. "Fine," I remarked. "When do we leave?"

Jan 1, 1947

By M. J. Marcinkowski, E. N. Hopkins

An investigation has been made of the ß(fcc) — a(hexagonal) transformation which occurs in lanthanum using both electrical resistivity and transmission electron microscopy techniques. It has been shown that the ß phase can be retained below the transformation temperature by rapid quenching but that the sample immediately begins to transform to the a phase. The transformation is observed to nucleate in the vicinity of inclusions. Based on the above observations, a detailed model of the transformation has been advanced which involves the nucleation of an extrinsic stacking fault bounded by a pair of Shockley partial dislocations in the vicinity of some heterogeneity, i.e., an inclusion. The stress field of the resultant dislocation pair acts to nucleate extrinsic faults in adjacent planes and leads quite naturally to the B-a conversion with a minimum of strain energy induced in the crystal. LANTHANUM possesses an fcc structure ß) (8) upon cooling transforms to a hexagonal modification (a) in much the same way as cobalt. The one exception, however, is that the stacking sequence of the closest packed planes in a La is ABAC ABAC, and so forth,1 whereas in cobalt it is ABAB, and so forth, i.e., hep. Mainly on the basis of transmission electron microscopy techniques, there seems to be little doubt that the 0 — a transformation in cobalt involves a dislocation mechanism2 although its exact nature still remains obscure. Although the ß - a transformation in lanthanum is somewhat more complex than that occurring in cobalt, it was thought that its very uniqueness would be helpful in understanding fcc — hexagonal transformations in general. Such a general understanding of these transformations is important since they represent what are perhaps the simplest of the martensitic class of transformations. The experimental techniques used were those of electrical resistivity and transmission electron microscopy. EXPERIMENTAL PROCEDURE The lanthanum used in this investigation was prepared by the calcium reduction of lanthanum fluoride in a tantalum crucible under an argon atmosphere as described by Spedding et al. The residual calcium was removed by vacuum remelting in a tantalum container. Portions of the metal were then analyzed by emission spectroscopy as well as vacuum fusion. The amounts of the various impurities that were found are listed in Table I. A portion of the lanthanum ingot was swaged at room temperature into 0.030-in.-diam rod for the resistivity samples while the remainder was rolled into 0.010-in.-thick sheet for the transmission electron microscopy phase of this investigation. In order to eliminate the plastic deformation induced in the samples during fabrication, they were sealed in evacuated tantalum lined quartz capsules and annealed for 1 hr at 700° C. Specimen resistances were measured using the conventional "four-wire" technique described by MacDonald, 4 employing a type K-3 Universal Potentiometer and a standard 0.001-ohm resistor, both manufactured by Leeds and Northrup Co. By taking into account all of the possible errors in the apparatus, it was felt that the absolute resistivities of the approximately 0.87-in.-long specimens measured are reliable to 3 pct. Resistances from room temperature to 700°C were measured using a vacuum furnace. In order to avoid sample contamination by the thermocouple, chromel-alumel leads were spot-welded into a tantalum shield which in turn was welded to the lanthanum specimen. Resistances below room temperature were obtained by transferring the sample to a helium gas-filled quench tube and slowly dripping liquid nitrogen into a surrounding dewar flask. A steady reduction of temperature to about —190°C was completed in about 23 hr, and the resistances were measured at various temperature intervals. As will be shown shortly, rapid quenching from above about 350°C was sufficient to suppress the B -a transformation initially but subsequent annealing at lower temperatures leads to a partial ß --a conversion. To investigate this aspect of the transformation, the samples were suspended in the hot zone of a helium-filled furnace from which they could be rapidly dropped into the quench tube mentioned previously which was now

Jan 1, 1969

By Howard M. Graff, Sidney C. Bouwer

The economics of mining has traditionally been viewed quite apart from the economics of blast furnace operations. It was realized, of course, that blast furnaces would operate best with good raw materials, but the shipping grade of ore, for example, was decided by a sort of collective bargaining process between the ore producers and the blast furnace operators. The mine operators had to keep their costs down, and were usually successful in convincing management that the ore in any particular deposit was endowed by nature with a certain iron content and that the mine grade could not be raised beyond a certain economic limit. The blast furnace operators would have liked a better grade, but as long as they were able to make a fairly good showing it was more or less accepted that they had to take the ore as it came. The mine operators were able to ship to the nation's blast furnaces thousands of tons of iron ore that would be completely unacceptable by present-day standards. As late as the early 1950's, the major steel companies were witnessing an actual decline in the iron content of their incoming ore supply as the mining companies mined progressively leaner material and upgraded it only enough to pass competitive market requirements

Jan 8, 1965

By John I. Yellott

SINCE the days of Newcomen and Watt, when men first sought to turn the energy of fuels to useful purposes, coal-generated steam has supplied most of the power needed for both stationary and mobile applications. The low efficiency and large water requirements of the nineteenth century steam-power plant caused many engineers to turn their thoughts toward more direct means of converting heat into power. As far back as 1791, John Barber secured an English patent on a combination' which he might well have called a "gas turbine." He proposed to generate procducer gas from coal or charcoal, to burn it under pressure in air obtained from a reciprocating compressor, and to drive a turbine wheel with the resultant hot combustion products. With the optimism characteristic of the inventor, he hoped that the turbine would not only operate his compressor but also perform useful work. There is no record that Barber ever built his machine, but if he had done so he would have learned that useful power can result from such a combination only when both turbine and compressor are highly efficient and when the temperature of the gas entering the turbine is not far below 1000°F. Hot-air prime movers continued to attract attention, and both Stirling in England and Ericsson in America2 built reciprocating engines that operated with some success upon coal-heated air. The internal-combustion engine, burning liquid fuels, supplanted the hot-air type, and, for the first time, challenged the supremacy of both the steam cycle and its familiar fuel, coal. LIQUID FUELS COMPETE WITH COAL As the increasing use of the automobile multiplied the demand for gasoline, the supply of residual fuel increased rapidly, and heavy oil declined in price to the point where it became competitive with coal. First in the marine field and later in stationary plants in areas adjacent to refineries, oil began to be widely used. Oil's greater convenience and higher heating value per pound of weight or per cubic foot of bunker space have caused it to take over much of the marine field. The introduction of the highly efficient diesel engine, capable of burning a fuel that is cheaper than gasoline, again threatened the position of coal, for the operating costs of the diesel became directly competitive with those of coal- burning equipment. In isolated power plants and smaller marine installations, the diesel provided the medium by which oil again successfully invaded fields formerly dominated by coal. The diesel engine, provided with an

Jan 1, 1946

By B. G. Matson, M. A. Whitfield, G. R. Dysart

This paper describes the development of u computer program to calculate changes that occur in the length of tubular goods due to temperature and pressure changes during stimulation operations. Due to the numerous variables involved and the uncertainty of all static and dynamic conditions that could exist, it becomes a staggering task for individuals charged with completions to perform the necessary mathematical calculations. The computer program permits advance calculations for several sets of conditions. INTRODUCTION In the Delaware basin of West Texas alone, 50 wells were contracted or drilled to 15,000 ft or deeper in 1965. Deep well activity is continuing in this and other areas on an expanding scale. Many of these deep wells require extensive stimulation for successful commercial production, and during these operations, pressures and temperatures are encountered that have a pronounced effect on the length of tubular goods. This length change during a large-volume, high-pressure stimulation treatment utilizing fluids considerably cooler than bottom-hole temperature can be of such a magnitude that permanent damage to casing and tubing will result unless mechanical design, pressures and fluid temperatures are evaluated and controlled. These pressure and temperature effects can be calculated. However, the process lends itself well to computer solutions because of the mathematical nature of the problem and the calculating hours involved in arriving at an answer. The engineering-hour demand becomes more severe as tapered strings are involved. On initial treatments on a given well, surface pressure and injection rate conditions are unknown, and offset well conditions have not proven to be a reliable method for making predictions. For these reasons, it has become rather standard procedure for operators to compensate for these uncertainties by placing unnecessary pressure and fluid temperature restrictions on stimulation design. On a number of occasions treating fluids have been preheated to as much as 160F as a means of compensating for thermal contmction resulting from pumping cool fluids. The maintenance of packer seals has been treated by Lubinski, Althouse and Logan',' and the problem of therma1 effects on pipe has been explored by Ramey." These works were expanded and the results made applicable to everyday oilfield terminology before submitting them to computer programming. The pressure and temperature effects on tubing movement previously mentioned occur simultaneously as fluid moves through the pipe. The pressure changes, for purposes of explanation, are categorized here as to the various effects these pressures have on a tubing string. These divisions are (1) the piston-like results of forces acting on horizontal surfaces exposed to pressure, (2) swelling or ballooning of the tubing along its entire length due to the forces of pressure acting against the tubing walls, (3) the elongation of tubing due to frictional drag and (4) corkscrewing of the pipe due to internal pressure. Thermal changes are also of great importance, as their results may be more significant than any of the pressure effects. Steel is an excellent conductor of heat and the earth is a relatively poor conductor. It has been calculated that pipe temperatures at depths of more than 20,000 ft approach within as little as 25" the temperfature of the surface fluid after pumping for 2 hours, or a drop in temperature in some treatments of more than 220F. The equations presented in this paper were developed for computer programming and simplicity of input information; therefore, numerical constants such as Young's modulus for steel (28 X 10\ si), the coefficient of thermal expansion of steel (6.9 X 10."IF) and Poisson's ratio for steel (0.3) are included with unit conversion factors. The moment of inertia of tubing cross-sectional area with respect to its diameter was changed to a constant times (D' — d') where D is outer diameter and d is inner diameter. Units in the equations are length in feet, diameter in inches, density in pounds per gallon, pressure in psi, rate in barrels per minute and time in hours. PISTON-LIKE REACTIONS A change in tubing internal dimensions and the exposure of other horizontal surfaces to different pressures on the inside and outside of the tubing result in a reaction much like a piston under pressure. Such is the case when the internal diameter changes in a combination string of pipe, when seals of a slick joint assembly are subject to pressure and in the end effects of a tubing string. The change in tubing length due to the piston effects of a slick joint packer is affected by the various diameters involved, the tubing pressure Ap,, the casing pressure ,Ap,, length of pipe L, densities of fluid in the tubing before and during pump-

By AIME AIME

THE Institute of Metals held a well rounded out symposium on the working of metals, distributed over two sessions. At the first session* four papers were presented, two dealing with the, cold working of metals and alloys and two with the hot working of non-ferrous alloys. The first paper by E. V. Crane, dealt with "Metal Working in Power Presses." Mr. Crane pointed out the empirical nature of engineering data available for use in calculating the probable stresses developed and power requirements, for the shearing, drawing, binding and other forming operations. He described the various operations, methods of determining stresses developed and presented data obtained. In the discussion C. F. Hammond took exception to Mr. Crane's objections to the rather too frequent. annealing operations in drawing of cartridge cases, pointing out that the material was-manufactured to meet specified structure and physical requirements, which could only be met by carefully controlled sequences of working and intermediate annealing operations.

Jan 1, 1931

By Charles Camsell

MORE than one-third of all Canada is embraced in the federal domain known as the Northwest Territories. Its most northern point, Cape Columbia, on Ellesmere Island, is only 500 mi. from the Pole. It includes parts of the main physiographic divisions of the North American continent. In the West there is a strip of 30.000 sq. mi. lying in the Cordilleran region, where peaks in the Mackenzie Mountains rise as high as 8500 ft. East of this strip and extending roughly to a line through Great Bear and Great Slave lakes to the Arctic coast is a section of the interior plains. This section, known as the Mackenzie Lowlands, contains the great artery, the most striking feature of the Northwest Territories-the Mackenzie and Slave river waterway impressive in its width, almost two miles in places, and in it's navigability for 1357 miles without obstruction to the sea. Adjoining the Mackenzie Lowlands on the East is the greater portion of the mainland of the Territories, which, as well as a large share of the island area, is in the Canadian Shield.

Jan 1, 1937

By Albert Sauveur

THE senior author of this paper has expressed the belief that when gamma iron transforms into alpha iron on reaching the A3 point, each gamma grain does not change bodily into one or more alpha grains but that the alpha phase forms first at the boundaries and along the crystallographic planes of the austenite grains.1 To quote: On cooling through the point A, at about 900° C., iron passes from the gamma condition to a. new allotropic form generally designated as alpha. This transforma¬tion, however, is not instantaneous. There are good reasons for believing that it begins at the grain boundaries and along the octahedral planes of the crystals and that it progresses until each grain of gamma iron is changed into a grain of alpha iron, the resulting structure being similar to that of gamma iron. Were it possible to retain at room temperature pure iron but partially transformed, it seems probable that a Widmanstättian structure, or rather, as later explained, a martensitic structure would be observed (Fig. 1), consisting of alpha iron at the boundaries and at the octahedral planes, and of a groundmass of gamma iron. In order to confirm, if possible, the accuracy of that view, a number of experiments were conducted. Polished samples of electrolytic iron were heated in a vacuum, maintained in the gamma range for several hours and quenched in different media. It was hoped by such means to produce and retain on the polished surfaces a pattern which would reveal the mechanism of the allotropic transformation. The samples were placed in evacuated quartz tubes, heated to 1000° C. and held 2 hr. at that temperature. The tubes were then immersed in the quenching bath. Iced brine and liquid air were used first. The polyhedral austenitic structure existing at the time of immersion was very clearly revealed (Fig. 2). This is generally ascribed to iron volatilizing at the grain boundaries.

Jan 1, 1929

By GILBERT E. SEIL

GREAT advances in the preparation of ores for reduction to ferro-alloys have been made, although standard methods of reduction have been continued at most plants. Efficiencies, yields per furnace, and energy requirements per ton are generally better than previously attained. The advantages of sizing and conditioning of ore, fluxing stone, and coke have been realized. Conditioning varies from drying the furnace burden to chemical rearrangements to facilitate reduction reactions and sometimes to furnish some of the energy required for the reaction before the burden reaches the furnace. During the war period it is impossible to discuss in detail many of the advances made. They are subjects for postwar papers. However, the new procedures mentioned in the following paragraphs are indicative of the work already done and in progress.

Jan 1, 1944

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951