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By Albert Sauveur

AT the New York meeting of the Institute, February, 1914, Professor Hopkinson and Sir Robert Hadfield presented an important paper entitled Research with Regard to the Non-Magnetic and Magnetic Conditions of Manganese Steel.1 Any contribution on manganese steel by its discoverer necessarily carries with it much weight and is entitled to serious and close consideration. The momentous discovery of that alloy by Sir Robert Hadfield some 30 years ago was the signal for great activity in the field of alloy steels; and the remarkable results obtained in the last two decades probably constitute the most important modern advance in the metallurgy of steel. The authors of the paper referred to above are unable to reconcile with the allotropic theory the interesting results obtained by them in heat treating manganese steel. When they speak of the allotropic theory, however, I understand that they have more especially in mind the existence of beta iron. It is not my understanding that they question the occurrence of iron in the two allotropic varieties known as gamma and alpha. If I am wrong, I trust they will correct me. A careful consideration of the experimental results reported and discussed by the authors leads me to believe that on the contrary they can be very satisfactorily explained in terms of allotropy and that, in the light of our present knowledge, they cannot be accounted for in any other way. The physical properties of non-magnetic manganese steel described by the authors are those pertaining to iron-carbon alloys in which iron is present in the gamma condition, or, in other words, to austenite. The metal is then characterized by great tenacity and ductility and low elastic limit, while its hardness, mineralogically speaking, is not excessive, but of a special kind termed "tough hardness" by the authors. Even when subjected to the restraining influence of a large amount of manganese and of considerable carbon, however, relatively rapid cooling

Jan 9, 1914

By Paul C. Ragland, P. Geoffrey Feiss

The Piedmont province of the southern Appalachians is the focus of interest for many exploration geologists. In the past, only those deposits with significant surface exposure were exploited. Thus, few deposits have been found and relatively little exploration has been conducted in recent years. Modern geochemical and geophysical techniques can alleviate this problem of concentrating on exposed ore bodies by allowing us to "look through" the soil and saprolite to detect the presence of significant mineralization at depth. This paper will attempt to evaluate the feasibility and effectiveness of several geochemical exploration techniques in the Piedmont province of Cabarrus and Stanly counties, N.C. The area chosen for study is shown in [Fig. 1], lying almost wholly within the Mt. Pleasant quadrangle, N.C. The area is on the eastern boundary between the Charlotte belt, a zone of plutonic and intermediate grade metamorphic rocks, and the Carolina Slate belt, a series of complexly interbedded volcanic and sedimentary rocks of predominantly low metamorphic grade. The area is considered to be an early Paleozoic active, continental margin. l As is typical of most of the piedmont, outcrop is sparse. [Figure 2] is a sketch map of the general geology of the area under study, showing the Charlotte belt rocks in the northwestern quadrant and slate belt rocks to the east. Within the area are a number of old mines and prospects, the most famous of which are the Furniss and Phoenix mines in Cabarrus County. All are reported to have contained Au and Cu. Ag and Pb were reported from some. A summary of the deposits is given in [Table 1]. Data used in this study are from three Master's theses completed at the University of North Carolina at Chapel Hi11. 3, 5, 6 In separate studies, well waters, 5 B-zone soils,3 and vein and float from the area were sampled and analyzed. Each study concluded separately that geochemical anomalies in the vicinity of the ores justify use of that specific sampling technique in a geochemical exploration program. However, no comparative study of the methods has been made. It is our intention

Jan 1, 1980

By E. F. Loiseau

IN a paper on the manufacture of artificial fuel, read at the Philadelphia meeting of February, 1878, I enumerated the difficulties which I had to overcome before succeeding in the mixing of coal-dust and clay, the compressing of the same mixture, and the water-proofing of the lumps. The drying of the lumps, after leaving the press, was the remaining difficulty, and it was expected that a plan devised by Dr. Charles M. Cresson, of Philadelphia, would enable us to dry the fuel as rapidly as it was moulded, and that a continuous production could in that way be obtained. The company was reorganized. The works were purchased by the new company at an assignee's sale, and the oven was modified, according to Dr. Cresson's plan. Anticipating a possible failure, I had prepared a plan by which I expected to be able to demonstrate that anthracite coal dust mixed with pitch, could be manufactured with our present machinery slightly modified ; so that after all, if we were compelled to give up the attempt to make fuel for domestic use, there was a possibility of succeeding in the manufacture of a good steam-fuel. The plan suggested by Dr. Cresson for drying the pressed lumps of coal-dust cemented with clay, did not work as well as we expected. It enabled us to dry more fuel than we did before, but it could not be made to dry more than one-half of the lumps produced by the press. The plan was abandoned, and I was authorized to experiment with coal-dust and coal-tar pitch. The cement which is used in Europe to conglomerate coal-dust is ,usually dry pitch, which is prepared by separating from the tar, at a temperature of 572° Fahrenheit, the volatile matters which it contains. Some manufacturers, however, employ crude tar, others, a rich tar, which has been cleared of 25 per cent. of its volatile substances, by heating it to 392° Fahrenheit. But with common tar very weak fuels are obtained, which do not burn well, and give out a strong smell and a great deal of smoke ; it is also necessary to subject them to a baking process, in order to solidify them, and to eliminate the more volatile of the materials contained. This operation of course requires a special plant, the cost of which increases sensibly the price of manufacture, without counting the products

Jan 1, 1880

By Richard P. Rothwell

FIRES in mines are so serious in their consequences and of such frequent occurrence, that their causes and the means of extinguishing them are certainly questions of the greatest interest to a large part of the engineering profession. We have already, in this country, many mines which have been burning for years, and though our hard anthracite is so difficult to ignite that for a quarter of a century after it was first discovered it was not known how to burn it except with the aid of an artificial blast, yet most of the fires which have occurred underground have been in anthracite mines, and in the coal itself. The injury which these fires have caused to properties in various parts of the anthracite regions, and the cost of extinguishing them, would amount to many millions of dollars, and they have also occasioned the loss of many valuable lives. It is not surprising, therefore, that the subject has already attracted much attention, and the exercise of great ingenuity ; and the present communication is made less with the expectation of announcing anything new, than with the object of putting upon record the present state of our knowledge on this subject, or, in other words, of indicating how defective are the present means of combating underground conflagrations. (Causes of Mine Fires.-Even upon the surface, fire is a terrible foe to contend with, and there is probably no other which inspires such thorough and well-founded alarm. With what feelings, then, must we look upon this destructive element, when its field is in the narrow galleries of a mine, where the poisonous products of combustion, spreading in every direction, protect, in the most effectual manner, the fire itself from the attacks of extinguishers, while, if the face of attack be ventilated so as to enable them to approach the seat of the fire, the air current simply increases the extent and violence of the conflagration. Fires underground originate in as various ways as those on the surface, and it is scarcely necessary to say that, except in the rare cases where they are the result of design, they are invariably classed as " accidents," and most generally as " unavoidable accidents." In reality, by an intelligent understanding of their causes and with due precautions, they can almost always be prevented. Ignorance and

Jan 1, 1876

By Frederick Becket

DOCTOR Albert Sauveur, distinguished scientist and Honorary Mem-ber of this Institute, predicted in the first Howe Memorial Lecture that the privilege of delivering this annual address would be considered a highly significant honor. The intervening years have well borne out Sauveur's prophecy. I wish to assure the American Institute of Mining and Metallurgical Engineers that I also deeply appreciate this honor, recognizing at the same time the present and even more the future respon-sibilities with which it is accompanied. Several of the previous lecturers had the good fortune to attend the classes of Professor Howe and to work in his laboratories. I was similarly favored, although in my instance and to my great regret the period was all too short. However, Howe's book, published in 1903, "Iron, Steel and Other Alloys," afforded me abundant opportunity to continue these studies. How well I remember the inspiration I derived from this famous book by Howe, the metallurgical master, pioneer, and educator! Remembering that Professor Howe contributed numerous papers to The Metallographist, a magazine supported from a technical point of view by the world's pioneers in metallography, I was curious a few days ago to learn the nature of Howe's early contributions to this magazine. The first paper by Howe in the first year of The Metallographist (1898) dealt with the allotropic theory; the second also treated of allotropy, and I quote the first sentence. of that paper: The allotropic theory of the hardening of steel may, like so many other important theories, have to be accepted or rejected not on direct proof or disproof, but on the accumulation of circumstantial evidence for or against it.

Jan 1, 1938

By Alfonso Rizo-Patrón, A. M. Gaudin

PREVIOUS studies of activation in flotation have directed attention to the action of the activator on the mineral to be floated rather than to the relationship of the activator to the collector. The latter phase of the problem, however, seems to have definite scientific, if not also practical, interest. In the investigation reported in this paper, experiments were carried out, largely with quartz as subject, barium as activator, and oleate as collector. The results obtained indicate that a I : I ratio of collector ion to activator ion gives optimum results, and that a 2:I ratio almost fails to achieve activation and flotation. Yet, a 2:I ratio would have been expected on stoichiometric grounds, had the coating been a normal salt of the activator ion with the collector ion, since barium is a divalent cation and oleate a monovalent anion. To interpret and rationalize the observations, considerations of the crystal chemistry of quartz are helpful. The point of view to which these considerations lead may be of general applicability to systems involving suspensions of solids in liquids; they confirm that an adsorbed coating is inescapable. APPARATUS AND SUPPLIES The experimental work consisted in barium-ion abstraction tests, hydrogen-ion and hydroxyl-ion abstraction tests, flotation tests, and determinations of the surface of the crushed quartz. The flotation machine was built according to the design of D. W. McGlashan.* It consists of a drill press in which the bit has been replaced by a stainless-steel impellor surrounding a stainless-steel stator, as in the Fagergren laboratory machine. The air intake is controlled by a valve, and the cell consists of a beaker. The quartz was obtained from vein quartz stored in large chunks. It was first crushed to 20 mesh, then sized on a 28-mesh screen. The 20 to 28-mesh size alone was retained for use. This size was freed of coarse iron by passage through a Ball Norton magnetic separator, bleached with boiling hydrochloric acid to remove residual abraded iron, washed with distilled water until the washings were thoroughly free of ferrous, ferric, and excess hydrogen ion, and stored in covered Pyrex beakers under water until used. The barium was used as barium chloride, Baker's analyzed C. P. The oleate was used as sodium oleate. It was prepared from sodium hydroxide, Baker's analyzed C. P., and oleic acid purified by R. R. de Arellano3 in the laboratories at the Massachusetts Institute of Technology. The purification procedure was elaborated from the recent researches of Brown and Shinowara.2 It consisted in: (I) saponification of olive oil with potassium

Jan 1, 1942

By D. K. Deardorff, Haruo Kato

D. K. Deardorff and Haruo Kato (U. S. Bureau of Mines)—We wish to refute the 1875" 20°C value that Giessen, et al., report as the transformation temperature of hafnium. Although these authors state that their work along this line will be reported later, we can't leave their value undiscussed, for we believe it to be 125°C too high. Our value of 1750° 20°C, which the authors mention, has been substantiated in our laboratories by the use of three other methods. The first method of substantiation was by heating and cooling curves using a hafnium/tungsten thermocouple, the couple having first been calibrated against a t/Pt-10 pct Rh couple. The second method was by quenching and metallography of dilute Hf-Ta alloys. The third cussion, it may be pointed out that the observations of Rogers referred to large unidirectional strains where the internal cracks or voids appeared only after a strain of 32 pct or more. On the contrary the internal fissures observed, as a result of fatigue cycling, occurred for a total extension of some 5 pct and furthermore followed the directions of the slip zones. Finally, it is not our contention, as implied in Dr. Alden's last paragraph, that the tensile stress is an important factor in crack propagation. Indeed, in connection with the reference to the companion report, special note is made of the fact that "Deformation was apparently concentrated in grains which have a slip plane nearly perpendicular to the specimen axis and thus near the plane of maximum applied shear." This dependence of the growth of fissures on the orientation of the slip planes with respect to the direction of maximum applied shear is clearly shown in work on the torsional cycling of single crystals which has been submitted for publication. method was by heating and cooling curves with W/W-26 pct Re thermocouple. Counting the original resistometric method, four different methods have yielded 1750" 20°C as the transformation temperature of hafnium. All our work on determination of the hafnium transformation temperature has shown that the specimen under test must be quickly heated to and through the transformation temperature if the lowest possible transformation value is to be determined; otherwise a higher value not representative of pure hafnium will result. Speed was emphasized in all methods. In our resistometric work the corresponding voltage, amperage, and temperature readings were taken quickly and the transformation temperature was usually reached within 5 min total heating time. In the thermal analysis work involving Hf/W or W/W-26 pct Re thermocouples the transformation temperature was attained within three minutes total heating time, this time being less because the two variables were

Jan 1, 1963

Report of the Secretary TO THE BOARD OF DIRECTORS AND THE MEMBERS OF THE AMERICAN INSTI¬TUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN As will be shown by the special reports of the Finance, Membership, Library, Papers and Publications, Increase of Membership, and other standing Committees, together with that of the Treasurer, the year 1927 was one in which the Institute made very satisfactory progress in a number of directions. In total numbers the membership is no larger but in revenue from dues there has been a marked increase. This has been due to the promotion to full membership of Junior Associates of earlier years, to the larger proportion that come in originally as members rather than juniors, and to the keener interest in the work of the Institute reflected in prompter payment of dues. The latter is important, since experience shows that of those who fall behind a large number must ultimately be dropped for non-payment. Conditions in the mining in¬dustries have been healthy though not booming. It has been much easier for members to find employment and meet their financial obligations but there has not been that flow of young men into mining, and hence in part into the Institute, that characterized certain earlier years. Rather the tendency toward centralization and larger industrial units has re¬stricted the number, though not the scope, of opportunities for technical men in the mineral industries. The Institute is constantly receiving resignations from members crowded out of mining into other lines of activity. On the other hand, those who remain in mining and metal¬lurgy have a greatly increased necessity for information and contacts with technology. A few years ago many superintendents and most foremen were non-technical men. Today the reverse rule obtains and shift bosses and men who occupy even lower positions in industrial units are called upon to know and to apply such an amount of technical knowl¬edge that graduate engineers are the rule rather than the exception. The curious situation has obtained that with a much smaller enrollment of students in the schools of mining and metallurgy there has been at times an actual shortage of young engineers for beginners' jobs. The young men retort that the conditions of employment and pay offered in mining are not equal to those in other lines and, while it is undoubtedly true that the young engineer beginning in mining is able to start under conditions markedly better as to pay, living, and responsibility than did the men who are now leaders, they are required to know much more and have usually spent more in time and money to qualify for their jobs. The whole matter is one which warrants much more attention than has been given to it. For the Institute it is important since the young men

Jan 1, 1923

By W. Vickers

Single-point rotating cantilever fatigue tests have been carried out at 550" to 650°C on beryllium produced by a variety of fabrication routes. All the specimens gave similar plots of stress against number of cycles to failure but failure occurred at a lower stress range in the hot-pressed material than in the extruded material. A discontinuity or "kink" appears to exist in the curves and this is considered. A true endurance limit was not evident up to 10 cycles. When Brush hot-pressed warm-extruded beryllium was tested at 600oC a relationship where Nf = number of cycles to failure, ?ep = plastic strain range, and c = constant, was shown to be applicable for values of ?ep > 6.3 x 10-4. Further for this moterial and temperature and for frequencies between 150 and 4500 cycles per min, the variation of number of cycles to failure with frequency obeyed the expression N = Af0.44 where N =number of cycles to failure, f = frequency, and A = constant. Examination of the fracture surfaces indicated that they were generally intergranular and in all cases the higher the stress the more irregular was the fracture. Microexamination has shown that grain boundary cavities and fine intergranular cracks were associated with the fractures. REVERSING or cyclic stresses set up in fuel elements can lead to failure by fatigue. Fatigue stresses may be developed by instability of the fuel element in the coolant flow leading to rattling against the channel wall or fin vibration. Thermal cycling also sets up reversing stresses due to differential expansion of fuel and can. Fatigue resistance is of some importance therefore in the evaluation of canning materials. At the time the work described in this paper was initiated, beryllium was being considered for the can and endcaps of an advanced gas-cooled reactor fuel element. With this in mind, beryllium obtained from different manufacturing routes was tested on single-point rotating cantilever fatigue machines at temperatures the same as those envisaged in the reactor to obtain appropriate fatigue data. The results obtained indicated a discontinuity in the S-N curves coinciding with the yield stress in the specimens. Although in some cases the data is insufficient to warrant a detailed quantitative analysis, a qualitative analysis of this effect was thought to be justified. 1) EXPERIMENTAL DETAILS The materials used are given in Table I together with the production route and available analyses. The specimen shape is shown in Fig. 1. The fatigue specimens were machined slightly oversize, after which they were given a stress-relieving anneal of 1 hr at '750° C in vacuum. This was followed by an etch in sulfuric-phosphoric-chromic acid mixture down to the finished dimensions given in Fig. 1. Etching served to remove the interference colored oxide film formed on the surface during annealing and very small recrystallized surface grains too. The specimen was mounted in the grips of a cantilever machine and rotated inside a furnace controlled at the testing temperature. The specimen was loaded in increments as the speed was increased until the required load was applied at 5000 cycles per min. A revolution counter was used to record the total number of cycles.

Jan 1, 1964

By L. Larson

SMELTERMEN in the copper industry know that punching the tuyeres of a copper converter is a difficult, disagreeable, and at times a hazardous job. Knowing this, many men in the industry have given serious consideration to punching by mechanical means. As evidence of such consideration, a great many patents have been issued covering various mechanical devices or machines for doing this task. In 1942, as war-created manpower shortages became more acute, it became increasingly difficult to get men to punch tuyeres. Faced with this situation at the McGill smelter, it was decided that an all-out effort should be made to develop some sort of a mechanical punching device. The various patents were studied over thoroughly but none of the devices seemed suitable, all were discarded and it was decided to develop one, using the ideas of the personnel at McGill. Initial test work indicated that a separate punching device should be attached to each tuyere. This meant that an adapter would have to be developed which would accommodate such a device; the adapter to be so constructed that it could be substituted for the regular Dyblie valve head, and be punched either by mechanical means or by hand. Also a method for quickly attaching or detaching the punching unit would have to be devised. If the punching unit was attached to the adapter, then the punch rod and tip would have to remain inside of and reciprocate within the tuyere pipe. This last requirement meant that the punching device, the adapter, the piston rod, and punch rod must be in perfect alignment. The whole arrangement thus would become an integral part of the converter and would rotate along with the tuyere line to all the positions required for converter operation. If the puncher was to rotate with the converter, there was also a problem of limited clearance. The construction of a device to meet all of these conditions imposed many problems. In the latter part of 1942, two pieces of equipment were constructed and tried out under test-stand conditions. Both of these devices were very crude, but test-stand operation indicated that progress was being made. Neither of the units was considered good enough to be attached to and tried out on a tuyere of an operating converter. In May 1943, work was started on another device and in August of that year it was attached to and actually punched a single tuyere of a converter on an experimental basis (fig. 1). This unit was essentially a cylinder 3 in. in diam and about 15 in. long inside. Valve ports were so located as to provide a 1-in. cushion on each end of the stroke. The cylinder ports were piped to a 3/4-in. four-way disk valve. High pressure air (90 psi) was delivered to the valve by means of a long hose, thus making it possible to supply air to the device at all operating positions of the converter. The forward and return punching strokes were accomplished by shifting the valve handle as required. With the 3/4-in. valve, stroke velocities from 15 to 18 fps were achieved. Punching with this experimental arrangement was carried on for some time, but many difficulties were encountered. The punch rod tips often stuck in the tuyere accretion, indicating that more energy of some sort was necessary to avoid sticking the punch rod. To overcome sticking, experiments continued with a speeded up unit and although progress was made, troubles of various kinds continued to appear. On this unit, piston cup seals passed the valve ports which proved to be of very poor construction. Also the piston, driven forward at approximately 28 fps, would often bottom metal to metal in the forward end of the cylinder causing both mechanical and operational trouble. Sometimes the punch rod and at other times the piston rod would break loose and be shot through the tuyere pipe into the converter. Bottoming and poor timing of valve reversal caused a bounce and a hesitation at the end of the forward stroke, with the result that the punch rod

Jan 1, 1951

By Paul A. Beck, M. N. Parthasarathi

By determining the (220) pole figure for OFHC copper rolled to 96 pct R. .A., the occurrence of four texture components of the type (135) [211] was confirmed. It was found that the total volume fraction of material close to the four symmetrical orientations of this type is larger than the volume fraction of the other components put together. THE rolling texture of copper was described by early investigators1'" as a mixture of components of the (110)[l12] and (112) [11l] types. Other studies, still using the qualitative photographic method of texture determination arrived, instead, at orientations of the type (135) [533] or (135) [211] for copper3'4 and at the closely related "Z-texture" for a fee nickel-iron alloy.5 The prevalence of this type of orientation, near (123) [412], in the rolling texture of aluminum and of copper was later confirmed by means of quantitative diffractometer methods.' However, in a recent paper7 Jones and Fell stated that the (110) [112] and (112) [111] double texture was in better agreement with the measurements of Young's modulus for cold-rolled copper.' These authors also expressed their belief that the "roll texture" can be determined by means of two photographic quasi-fiber texture patterns taken with sheet specimens rotated around the rolling direction and the transverse direction, respectively. Jones and Fell found7 that the results obtained from such patterns for cold-rolled nickel did not agree with any of the orientations mentioned above, but they suggested that the observed diffraction spots may have been brought about by the overlapping of reflections due to the (110) [112] and (112) [11l] double texture components. Jones and Fell concluded that the (123) 14121 type orientation is inconsistent with their patterns. They also stated, without offering any supporting evidence, that this orientation is inconsistent with the (220) pole figure. "Ideal orientations" are often used for a very rough description of the principal orientations encountered in a texture, It is, however, well to remember the fact that, no matter how "accurate", these ideal orientations are only schematic representatives of a continuous distribution9, which often (as in the case of rolled copper) includes extensive orientation spreads. The attempt by Jones and Fell7 to use elastic modulus data in deciding between various ideal orientations in the rolling texture of copper neglects this fact. The inadequacy of two-dimensional "axis density figures" in describing orientation distributions in sheet textures was previously discussed.9 It was also pointed out9 that there is no reliable evidence to prove that orientation distributions derived by the "quasi-fiber method" from rotated sheet specimens are fully equivalent to the corresponding information obtainable from quantitative pole figures. The view that a sheet texture could be adequately determined by means of two photographic quasi-fiber texture patterns is obviously erroneous9. The question as to the consistency with the (220) pole figure of ideal orientations derived from the (111) and (200) pole figures is, on the other hand, certainly very relevant. Since no quantitative (220) pole figure for cold-rolled copper appears to be available in the literature, the following work was undertaken. EXPERIMENTAL METHOD An extruded rod of OFHC copper, 1 in. in diam, was given alternate rolling (30 to 35 pct R.A.) and

Jan 1, 1962

By Charles L. Mantell, Kurt Straler

The hydrogen reduction of Cr2O3 to chromium metal was found to be feasible at very low water-vapor concentrations, corresponding to dew points of -38° to -24°C, over a temperature range of 1130" to 1490°C. Hydrogen reduction under these conditions was predicted by the calculated equilibrium curves which also indicated that CrzOs is reduced directly to chromium without forming the intermediate oxide, CrO. This reduction path was confirmed by X-ray diffraction analysis. The percent reduction of Cr2O3 at each reaction temperature was constant with time, suggesting an inhibiting effect of water vapor. A small increase in the residual water-vapor concentration of a single temperature, 1490°C, strongly retarded the rate of reduction This effect was expressed by an empim'cal equation which indicated a direct relationship between "distance from equilibrium" and the rate of reduction. me effect of temperature over the range of 1130" to 1490°C was expressed in an Arvhenius plot of log rate vs reciprocal absolute temperature. From this curve the apparent enthalpy of activation was found to be 29,600 cal. Based on the hypothesis that the rate of reductiun is contvolled at the oxide-metal interface, an over-all rate equation consistent with the experimental data and the thery of absolute reaction rates was formulated. A simplification of this expression to an Arrhenius equation was justified by the overriding effect of temperature on the rate of reaction for the minimum water-vapor concentration range. MOST of the metals in Subgroup V1 of the periodic table can be prepared commercially by direct reduction of their oxides by hydrogen or carbon monoxide, at temperatures considerably below the melting points of both the metals and their oxides. Chromium is an exception, being generally reduced from its ore, Cr2O3 . FeO, by silicon in an electric arc furnace which operates above the melting point of the Fe-Cr alloy or above the melting point of chro- mium if a chromium oxide be the starting material. In reduction of chromium oxide by hydrogen, either reduction does not occur at all or the rate of reduction is extremely slow. Theoretical considerations based on the high, exothermic, free energy of formation of Cr2O3 compared to the oxides of the other Subgroup VI metals, molybdenum, tungsten, and uranium, would also suggest a slow rate of reaction and a high activation energy. Interest in the direct gaseous reduction of fine-powdered ores in fluidized beds was considered justification for examination of this reaction. In order to develop a basis for a continuing study of the commercial feasibility of the direct gaseous reduction of chromite, a study of the kinetics of the reduction of Cr2O3 with hydrogen was undertaken. To the authors' knowledge no accurate kinetic data for this reaction have been obtained. Neither has an activation energy been determined nor has an attempt been made to establish a mechanism of reaction. LITERATURE Maier10 compared the data of I. Y. Granaat,6 H. von Wartenburg and S. Aoyama, and G. Grube and M. Flad7 with that derived from calorimetric and ther-modynamic properties for the equilibria for the reduction of Cr2O3 with hydrogen. These results, plotted as the log of the equilibrium constant vs absolute temperature for the reduction of Cr2O3 and the intermediate oxide, CrO, to chromium, show agreement between the differently derived data. In both cases the equilibrium constants were extremely low. Maier showed that, over a temperature range of 1000° to 2000°K, Cr2O3 is more readily reducible than CrO. Granat assumed that CrO was preferentially formed from Cr2o3 above 1100°C. Grube and Flad's analysis of their reaction products in the 895" to 1000°C range indicated the coexistence of only Cr2O3 and chromium. The hydrogen reduction of the other Subgroup VI metals, molybdenum, tungsten, and uranium, shows that reduction of the higher oxide proceeds through all of the intermediate oxides before being reduced to the metal. Since evidence pointed to an anomaly in the reduction behavior of Cr2O3, the authors investigated the reduction path of Cr2Os.to chromium. This was done theoretically with more recently available free-energy data and experimentally by X-ray diffraction analysis. This work reinforces Maier's conclusion.

Jan 1, 1964

By Howard N. Eavenson

ALL of the matters so far taken up by the Institute Committee on Stabilization of the Coal Industry will be of help, but it seems to be that under present conditions not very much can be expected until the railroad situation has been improved. As an instance of this, I would cite the fact of our experience at our mines in West Virginia and Kentucky. During 1917 and 1918 at our West Virginia plants we produced for our own consumption, practically entirely in the Chicago district, about 4,750,000 net tons of coal. In 1919 our output was reduced to 3,500,000 tons, this being caused partly by the shortage of orders in the few months following the armistice, but more particularly by The car shortage which began last September and continued throughout the remainder of the year, with the exception of December. This car shortage has been more acute since the first of the year, and while we now have an actual capacity here of 20,000 tons daily and have the equipment to produce it, with the possible exception of a few houses, we are able to average only about 12,000 tons, and in consequence, about 30 per cent. of our by-product ovens in the Chicago district are idle, and a number of blast furnaces are down for the want of coke. These figures, of course, refer to conditions before the strike of switchmen in April was started.

Jan 1, 1920

By F. A. Forward, J. Halpern

A new process for extracting uranium from ores with carbonate solutions is described. Leaching is carried out under oxygen pressure to ensure that all the uranium is converted to the soluble hexavalent state. By this method), alkaline leaching can be used successfully to treat a greater variety of ores, including pitchblende ores, than has been possible in the past. The advantages of carbonate leaching over conventional acid leaching processes are enhanced further by a new method which has been developed for recovering uranium from basic leach solutions. This is achieved by reducing the uranium to the tetravalent state with hydrogen in the presence of a suitable catalyst. A high grade uranium oxide product is precipitated directly from the leach solutions. Vanadium oxide also can be precipitated by this method. The chemistry of the leaching and precipitation reactions are discussed, and laboratory results are presented which illustrate the applicability of the process and describe the variables affecting leaching and precipitation rates, recoveries, and reagent consumption. THE extractive metallurgy of uranium is influenced by a number of special considerations which generally do not arise in connection with the treatment of the more common base metal ores. Perhaps foremost among these is the very low uranium content of most of the ores which are encountered today, usually only a few tenths of one percent. A further difficulty is presented by the fact that the uranium often occurs in such a form that it cannot be concentrated efficiently by gravity or flotation methods. In these and other important respects, there is evident some degree of parallelism between the extractive metallurgy of uranium and that of gold and, as in the latter case, it has generally been found that uranium ores can best be treated directly by selective leaching methods. It is readily evident that this parallel does not extend to the chemical properties of the two metals. Unlike gold, which is easily reduced to metallic form, uranium is highly reactive. It tends to occur as oxides, silicates, or salts. Two ores are of predominant importance as commercial sources of this metal: pitchblende which contains uranium as the oxide, U3O51 and carnotite in which the uranium is present as a complex salt with vanadium, K2O-2UCV3V2O5-3H2O. These ores may vary widely in respect to the nature of their gangue constituents. Some are largely siliceous in composition, while others consist mainly of calcite. Sometimes substantial amounts of pyrite or of organic materials are present and these may lead to specific problems in treating the ore. Further complications may be introduced by the presence of other metal values such as gold, copper, cobalt, or vanadium whose re- covery has to be considered along with that of the uranium, or whose separation from uranium presents particular difficulty. In general, there are two main processes for recovering uranium in common use today.'.2 One of these employs an acid solution such as dilute sulphuric acid to extract the uranium from the ore. A suitable oxidizing agent such as MnO, or NaNO, is sometimes added if the uranium in the ore is in a partially reduced state. The uranium dissolves as a uranyl sulphate salt and can be precipitated subsequently by neutralization or other suitable treatment of the solution. The second process employs an alkaline leaching solution, usually containing sodium carbonate. The uranium, which must be in the hexavalent state, is dissolved as a complex uranyl tricarbonate salt, and then is precipitated either by neutralizing the solution with acid or by adding an excess of sodium hydroxide. The latter method has the advantage of permitting the solutions to be recycled, since the carbonate is not destroyed. This is essential if the process is to be economical, particularly with low grade ores. With each of these processes, there are associated a number of advantages and disadvantages and the choice between using acid or carbonate leaching is generally determined by the nature of the ore to be treated. In the past, more ores appear to have been amenable to acid leaching than to carbonate leaching and the former process correspondingly has found wider application. With most ores, acid leaching has been found to operate fairly efficiently and to yield high recoveries. One of the main disadvantages has been that large amounts of impurities, such as iron and aluminum, sometimes are taken into solution along with the uranium. This may give rise to a high reagent consumption and to difficulties in separating a pure uranium product. Excessive reagent consumption in the acid leach process also may result

Jan 1, 1955

By Milton H. Fies

THE writer wishes to acknowledge at the outset his great sense of obligation to those who contributed so broadly and expertly to the preparation of this paper: Dr. Albert DeSmaele, Chairman of the Board of Directors of Socogaz, Belgium; Dr. Julien Venter, Director of the National Institute of Coal Mining and Coal Utilization Industry, Belgium; Dr. Roger Loison, Chief Engineer, French National Coal Research Board, France; and Dr. Erich Sarapuu of the Sinclair Coal Co., Kansas City, Missouri. Liberal use has been made in this paper of a recent publication on Russian, Italian, Belgian, and French experiments prepared jointly by the Centre d'Etudes et Recherches des Charbonnages de France (Cerchar) and the Institut National de l'Industrie Charbonnière of Belgium (Inichar).1 The writer is particularly indebted to Dr. E. T. Wilkins, of the Fuel Re¬search Station, London, and to Mr. James L. Elder, of the Alabama Under¬ground Gasification Experiment at Gorgas, Alabama, for their unfailing patience and effective support. Not only did these experienced and capable men edit and revise this discussion, but much of its content is a direct con¬tribution quoted in full from their memoranda. Without the assistance of all these colleagues, this presentation would not have been possible. It has been a privilege to serve and work with them and to acknowledge repeatedly their loyal cooperation. The recovery of the energy inherent in coal beds throughout the world has been done through the years by methods that today may be justly regarded as primitive. While the techniques of coal mining through the application of machines and the enhancement of information and skills have advanced to an extraordinary extent, particularly during the past 20 years, the underlying means is essentially the same as when man first began to mine coal. Despite this progress in the manner of coal mining, it continues today as a hazardous, toilsome, grimy task. Coal mining per se has advanced at a greater and more rapid stride in the past 25 years than the mining of any: other mineral, but the basic method is fundamentally the same as it was the first day a miner took a pick into his hands many centuries ago. This situation presents a challenge to mining engineers everywhere, from

Jan 1, 1953

By E. D. Gardner, E. M. Sipprelle

The Synthetic Liquid Fuels Act (58 Stat., 190; 30 U.S.C. Sup., Secs. 321-325) was approved by Congress April 5, 1944; it directed the Bureau of Mines to build demonstration plants to produce synthetic liquid fuels from coal, oil shale, and agricultural products. The most important oil-shale deposits in the United States are in the Green River formation of Colorado, Utah, and Wyoming. The oil shale of western Colorado generally is more amenable to exploitation, more persistent, and apparently richer than elsewhere in the Rocky Mountain Region. It occurs at the top of a high plateau surrounded by bold, nearly vertical escarpments 500 to 600 ft in height. The top 400 to 500 ft of these escarpments comprises an oil-shale measure that averages 15 gal of shale oil per ton; the bottom 70 90 100 ft of the measure, called the Mahogany Ledge, averages over 30 gal per ton. The full measure in a 1000-square-mile area is estimated to contain 300 billion barrels of shale oil;' the Mahogany Ledge is estimated to contain 100 billion barrels of oil. These estimates are based on numerous surfac,e samples and on core-drill holes drilled by the Government and by private enterprise. The oil-shale beds are undisturbed and lie nearly horizontal. The name "oil shale" is unfortunate, as the rock is a tough, strong marlstone. Organic matter named "kerogen" is a constituent of the rock. The oil-shale demonstration mine is on Naval Oil-Shale Reserve No. 1; it is about 5 1/2miles by mountain road from the plant site, which, in turn, is 2 miles from U.S. Highway 6 and 10 miles west from Rifle, Colo. The highway parallels the Colorado River, the Denver and Rio Grande Western Railroad, and a 66,000-volt public-utility power line. Early in the program it was realized that an oil-shale enterprise would have to be on a large scale to be commercial, and that unusually low mining costs would be necessary. The physical characteristics of the Mahogany Ledge and an overlying roof stone are unusually favorable both for large-scale operation and low mining costs. Quarry practices largely will be followed underground to mine the Mahogany Ledge. The aim has been toward complete mechanization of all mining operations. A mining unit would comprise a square mile containing 100,000,000 tons of oil shale with allowance for mining losses. An investment of $1,000,000 would be $0.01 a ton; such an expenditure, therefore, could be made to save, say, $0.015 per ton daily operating cost. A goal of a mining cost of $0.50 per ton was set up in 1945. Open-cut mining costs then were about $0.25 per ton of material handled; it was hoped that a cost double this amount could be obtained in mining the Mahogany Ledge. Costs of labor and supplies have increased since 1945 and so has the selling price of petroleum products. To those unacquainted with the character of the Green River deposits, the name "shale" suggested high mining costs. Others assumed that coalmining costs of $2 to $5 per ton would apply. To many, the expected mining costs appeared the principal handicap to the establishment of an oil-shale industry. The purpose of the Bureau of Mines is to demonstrate methods and to establish costs for mining the oil shale on a large scale. It is hoped this work will lead to the establishment of a large-scale, commercial oil-shale enterprise.

Jan 1, 1950

By E. E. Wahlstrom

The Harold D. Roberts tunnel, in Summit and Park Counties, Colorado, is a concrete-lined pressure tunnel finished to a circular cross section of 10.25 ft diam. The tunnel is 23.3 miles long and is designed to transport water for domestic use by the City and County of Denver from reservoir storage at Dillon to a tributary of the South Platte River at Grant. The tunnel passes beneath the Continental Divide at the crest of the Front Range and intersects rocks of diverse types and origins and geologic structures of extreme complexity. Geologic investigations preceded and were continued during construction and contributed materially to the safe and economical advance of the tunnel headings. Geological data obtained and evaluated during construction include plans and sections on a scale of 1 in. to 50 ft, rock temperatures at 2000-ft intervals, records of progress related to geology, records of ground-water conditions, summaries of the use of steel and timber supports, and summaries of grouting operations. Adverse conditions required use of steel and timber supports for 71.74% of the total length of the tunnel. Most supported sections reached a condition of equilibrium within a few hours to a few months after being excavated, and the concrete lining serves chiefly to provide an additional safety factor and to provide necessary hydraulic characteristics to the tunnel. Efforts to attain a maximum rate of advance of the tunnel headings necessitated use of more steel and timber supports than would have been required in a less accelerated tunneling operation. This report summarizes geologic investigations prior to and during construction of the Harold D. Roberts tunnel in Summit and Park Counties, Colorado (Fig. 1) and analyzes the tunneling operation as it is related to the various kinds of geologic conditions encountered in the tunnel. The tunnel is concrete lined to a circular cross section of 10.25 ft and is designed to transport 788 sec ft from reservoir storage at Dillon 23.3 miles along a dog-leg course passing under the Continental Divide to outlet and control works at Grant, Colo. The primary purpose of the tunnel is to augment the domestic water supply of the City and County of Denver, but plans include provisions for power generation at the outlet portal at a future date. Location of the tunnel was made after extensive preliminary geologic and engineering investigations by the Board of Water Commissioners of the City and County of Denver, and the U.S. Bureau of Reclamation. In 1946 the Board of Water Commissioners started tunnel driving on a limited scale from the east (outlet) portal and by 1955 had completed 9986 ft of tunnel. An urgent need for additional sources of water supply required acceleration of the tunneling operation, and, in 1955, Tipton and Kalmbach Inc. of Denver were assigned the responsibility of reviewing the project and preparing plans and specifications for the tunnel and appurtenant features. Additional geologic studies were made, and the geology of several possible alternate tunnel lines were compared before determining that the tunnel should be driven along the course previously adopted by the Board of Water Commissioners. On July 12, 1956, a contract for construction was awarded to Blue River Constructors Inc., a combine

Jan 1, 1962

By C. W. Spencer, Che-Yu Li, R. J. Knight

The usual reaction product for the monotectic reaction in the Bi-Se system consists of rod -shaped particles of selenium-rich liquid embedded in a single crystal matrix of At certain crystallo-graphic orientations of the matrix with respect to the reaction interface, more complex shapes are as -sumed by the liquid particles. This reaction has been examined at different growth rates and relative crystallographic orientations of the matrix with respect to the reaction interface. The uhriation in auerage particle size of the liquid phase with reaction rate has been determined at one crystallograpIzic orientation of the matrix. On a plot of logarithm of average particle diameter vs logarithm of reaction rate, data points for crystals grown at rates of 10- to 1.0 cm per hr fall near a curve of slobe -0.4. MONOTECTIC reactions in binary alloy systems are reactions of the eutectic class in which, as the system is cooled through the three-phase reaction isotherm, one liquid phase (L) decomposes to a solid phase and another liquid phase (LII).' A partial phase diagram, as taken from Hansen, showing the monotectic reaction in the Bi-Se system is given in Fig. 1. This diagram specifies the monotectic point at 618°C and 72 at. pct Se, and the monotectic reaction products as the intermetallic Bi Se3 and a liquid (LII) which contains approximately 98 at. pct Se. At a lower temperature, 217°C, this liquid may undergo a eutectic reaction in which the reaction products are BizSe3 and crystalline selenium. However, under conditions of rapid cooling, or quenching, from above 217°C, this selenium-rich liquid may be partially retained to room temperature in an amorphous or glassy state. The intermetallic BizSe3 is rhombohedral, of the space group jm;' however, for convenience it is usually represented by a hexagonal struture. A pronounced plane of cleavage, which lies perpendicular to the main axis of the rhombohedral unit cell or parallel to the basal plane of the hexagonal cell, exists in the structure. The usual monotectic reaction product consists of rod-like particles of LII embedded in a single-crystal matrix of BizSe3, although at certain crystallographic orientations of the matrix BizSe3 other more complex shapes are assumed by LII. A similar rod-like, or cylindrical, morphology for the carbide phase has been reported by westbrook7 in the a Cr-Crz3Ce eutectic structure. In this paper the morphological characteristics of the LII particles, as retained to room temperature, have been examined under conditions of varying growth rate and crystallographic orientation of the matrix BizSe3 with respect to the growth direction. EXPERIMENTAL PROCEDURE Alloy specimens corresponding to the monotectic composition, 72 at. pct, or 50 w pct Se, were prepared from 99.999 pct pure bismuth and selenium obtained from the American Smelting and Refining Co. The two elements, corresponding to a total specimen weight of approximately 30 g, were encapsulated in 13 mm OD Vycor tubing under a vacuum of 5 x X mm of Hg. The capsules were suspended on a fine platinum wire in a Bridgman-type furnace which exhibited a temperature gradient of

Jan 1, 1963

By Charles H. Fulton

(Cleveland Meeting, October, 1912.) I. INTRODUCTION. THERE are comparatively few accurate data on the melting-or the freezing-point temperature of metallurgical slays, or on related physical phenomena, such as fluidity near the melting-point, specific heat, latent heat, etc. With the exception of the work of H. 0. Hoffman,1 and some older work by R. Akerman, P. Gredt, and H. M. Howe, no information is available that is of direct interest to the metallurgist. Hofman's valuable work is the only one that refers to slags produced in the metallurgy of copper and lead. The classic work of J. H. L. Vogt,2 who views slays from the standpoint of physical mixtures (solutions in which the entities are minerals), has opened up a. new field in the study of slags, and has placed the investigation of such properties as melting-temperatures, etc., on a rational basis. The recent work of A. L. Day, E. T. Allen, and W. P. White, of the Carnegie Institution, at Washington, and of European investigators 3 on certain systems of silicate minerals confirms the value of the investigation of silicate series from this standpoint, and it is my aim to apply this method to metallurgical slaws, in order to gain exact data of value in metallurgy. The work recorded in the present paper is the result of an investigation of reverberatory-furnace slags made for a Western smelting company to determine exactly the influence of change in composition, within comparatively narrow limits, on the melting-point. For a general discussion concerning the mineralogical character of slaws and the principles on which this investigation is based, reference should be made to other work,4 for the subject is too large to be stated in this paper, except very briefly in the following outline 1 Trans., xxix., 682 (1899). 2 Die Silikatschmelzlösungen; I. Ueber die Mineralbildung in Silikatschmelzlösungen; II Ueber die Schmelzpunkt-Erniedrigung der Silikatschmelzlösungen (Christiania, 1903-04). 3 Doelter, Handbuch der Mlineralehevu:e (1911) 4 C. H. Fulton, Principles (of Metallurgy. Chapter viii., on Slags, p. 24.5 (1910).

Dec 1, 1912

By P. Marier, T. R. Ingraham

When cylindrical powder compacts of nickelous oxide (NiO) are heated in an equilibrated stream of SO3, SO,, and 02, in the temperature range 500°to 800°c, tlickelous suljate (NiSO4) is formed as an adherent layer on the oxide. The reaction is diffusion-controlled, with an activation energy of 13 ± 3 kcal per mole. When cylindrical powder compacts of NiSO4 are heated in a stream of dry nitrogen in the temperature range 1000 0to 11500C, NiO is formed at a well-defined interface between the sulfate and oxide. The interjhce migrates into the sulfate at a constant rate at a constant temperature and gas flow. The reaction rate increases with increasing gas flow and decreases with increasing partial pressure of SO3 in the gas stream. Resolution of the partial-pressure data with a Lang-itzliir Adsorption Isothern suggests that about 80 pct of the NiO interface is covered with SO3. The heat of adsovption is about 68 kcal per mole. The activation energy of the decomposition process is 61 ± 3 kcal per mole. MOST of the work reported on the formation and decomposition of nickel sulfate is related to thermodynamics.1-3 No quantitative work has been reported on the decomposition process. The only kinetic work reported on the formation is that by Fletcher and shelef.4-6 whose main purpose was to study the effects of alkali metal sulfate additions on increasing the rate of nickel sulfate formation. They found that, in the absence of an additive, only small amounts of sulfate were formed and the kinetic data were difficult to interpret. However, they suggested that the sulfa-tion of nickel oxide is a diffusion-controlled process for which the activation energy is approximately 17 kcal per mole.6 In this paper, both the formation and decomposition reactions will be examined; and based on the effects of temperature, flow rate, interfacial area, and partial-pressure of sulfur trioxide, mechanisms and activation energies will be suggested for both processes. EXPERIMENTAL Material. The nickel source material used in all experiments was Baker and Adamson Reagent Grade NiSO4. 6H2O, for which the following analysis was supplied by the manufacturer: C1, 0.001 pct; NO3, 0.005 pct; Co, 0.02 pct; Cu, 0.005 pct; Pb, 0.002 pct; Fe, 0.001 pct: insol, 0.005 pct. The anhydrous sulfate was prepared by heating the hydrate at 420°C in a muffle furnace for 5 hr. Nickel oxide was prepared by decomposing the sulfate at 950°C over a period of 10 hr. Method. The technique used for measuring the rates of formation and decomposition was developed earlier in these laboratories.7-8 The method is based on the observation that the kinetic parameters of a reaction can be established in a flow system, with specimens prepared by compacting powder to a uniform pellet shape. The results are identical with those established with solid polycrystalline specimens or single

Jan 1, 1967