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By J. H. Henderson, H. J. Ledbetter, N. B. Gove, J. D. Griffith

INTRODUCTION The results of a series of laboratory flood tests using liquid Iso-butane to displace refined oils from test cores are pre- ented and interpreted on an empirical bask. The study Revealed the similarity of the miscible liquid displacement to that of the immiscible-fluid displacement mechanism. The efficiency of the iso-butane flood decreased markedly as the oil Viscosity increased. but the effect of injection rate on the effectiveness of the primary production stage was negligible over the range investigated. The presence of free-gas saturation prior. to iso-butane breakthrough increased the volume of iso- Butane required to recover a given percentage of the oil present. Injection of liquid i.e.-butane prior to water follicle sculpted in a marked improvement in oil recovery by the water flood. INTRODUCTION The production of petroleum is often enhanced by the injec-1i1)n of extraneous fluids into the reservoir. It has been suggeited that the injection or cycling of a wet gas or a liquefied petroleum gas would he instrumental in increasing the effic.ienr!; of oil recover! to a greater degree than the commonly injected fluids. dry pas and water. Although instances of injection of light liquid hydrocarbons are not unknown, a systrmatic recording of the result is unavailable and superfi- cially, the practice gives the impression of being economicaIIy unsound. For specific types of displacement, analytic: solutions have been advanced which aid in understanding the physical mechanisms involved. However, there is no generalized theoretical concept which permits adequate prediction of displacement efficiency from a knowledge of readily measured reservoir rock and fluid properties. The Buckley-Leverett approach to oil displacement by an immiscible phase is an admirable analysiy of that type of mechanism. Dykstra and Parsons have introduced a useful concept in their evaluation of the role of the mobility ratio and its merit in rationalizing displacement phenomena. Everett, Gooch and Calhoun3 in their report on the effect of viscosity ratio and miscibility have pointed out the lack of a comprehensive theoretical approach and the desirability of investigating the mechanism of miscible-miscible displacement. In lieu of a well-developed theory concerning miscible-111isci1)le displacement and in view of the scarcity of engineering information on actual LPG injection trials, the limited program of laboratory experimentation described below was undertaken. OBJECTIVES The original broad objectives of the program, to study the oil recovery process using LPG as the displacing phase, defined the direction and scope of the laboratory tests. The specific objective. of the experimentation were to evaluate

Jan 1, 1953

By Norman B. Pilling, George P. Halliwell

The effects of lead and tin up to maximum contents of about 0.1 per cent. each, in the presence of oxygen between 0.04 and 0.30 per cent., have been studied. Tin is retained efficiently in the oxidized condition, whereas lead is not. An approximate relation between the lead-oxygen and tin-oxygen contents is deduced which, if observed, permits the presence of these elements without detrimental effect. Excess of lead beyond this limit affects ductility and rolling properties adversely and an excess of tin correspondingly diminishes the conductivity. It is shown that copper carrying a combined lead and tin content of several hundredths per cent., yet fully equal in quality to electrolytic wirebar, may be produced under commercial conditions. Tin is not normally found in more than bare traces in current grades of American electrolytic copper, and lead is rarely found to more than a few thousandths per cent. In the electrolytic refining of copper these metals do not present great difficulty in separation and their presence in any considerable amount in copper that has been refined by this method need not be tolerated. On the other hand, the effect of these elements is not entirely academic, as a considerable tonnage of scrap copper liberally contaminated with them has been reclaimed by the fire-refining process into metal with a residual lead and tin content of several hundredths per cent., yet having excellent working properties and fully equal in quality to current grades of electrolytic wirebar. Such copper has been found entirely suitable for use in the manufacture of electrical apparatus. In the absence of oxygen, tin is known to depress the conductivity rapidly, and lead to impair ductility and the rolling properties, yet the effects of these metals on commercial grades of copper—i. e., copper containing from 0.03 to 0.10 per cent. of oxygen—apparently has not received systematic attention. Occasional reference is made to the fact that in the presence of oxygen lead may be tolerated, yet Addicks says,1 in regard to overpoling: "The unstable condition can be controlled by adding certain substances, notably lead, in small quantities, but as mere

Jan 1, 1926

By J. T. Norton, N. J. Grant, I. S., Servi

Coarse grained high purity aluminum was tested in creep at temperatures of 400° to 1200°F to develop subgrain structures. Measurements of subgrain size, distribution, and rotation were made from X-ray diffraction patterns. Subgrain size and distribution were checked metallographically and the size was compared with average slip band spacing. The slip family was determined for several specimens. THE interest and research recently evident abroad in the role of subgrain formation and polygon-ization as a contribution to the creep of metals at elevated temperatures is deserving of greater attention in this country. Such metallic subgrains can be defined as macroblocks existing within the grains. The general observation has been that the macro-blocks which belong to the same grain have a maximum difference in orientation of a few degrees. In spite of the considerable amount of work that has been done since Jenkins and Mellorl observed the "division of existing crystals into smaller units when deformation occurs at an annealing temperature," the subject of subgrain formation is only now receiving truly active discussion and investigation. The existence of subgrains has been revealed by metallographic methods, as in the work of Jenkins and Mellor,1 and by X-ray methods, first applied to this problem by Homes.' Hirst3 and Calnan and Burns4 applied the back-reflection Laue technique to the study of coarse grained specimens. Wood et al.5 and Greenough and Smith' examined the ring obtained with a back-reflection camera for the study of fine grained specimens. In addition to the above, the transmission technique was used by Wood.6 A special technique was developed by Guinier and Tennevin8 in order to improve the resolution. Metallographically, the subgrains have been observed directly on the surface of deformed specimens by Wood et al.,3 or have been made evident on repolished surfaces by applying a suitable etching reagent. The latter technique, first suggested by Lacombe and Beaujard,9 was then improved by Wyon and Crussard.10 Subgrains can be formed in single crystals after small amounts of bending followed by heating after this cold work, or during deformation at elevated temperatures. The first phenomenon was analyzed by Cahn11 for the simple case of pure bending followed by annealing. Cahn suggested a mechanism of subgrain formation based on the dislocation theory and called this phenomenon "polygonization." He extended this mechanism to the more complex case of local bending, such as the bending which may occur when a polycrystalline specimen is deformed in tension. Cahn's suggestion was later found quite consistent with the results obtained by Dunn and Daniels." An explanation has been presented recently regarding the formation of subgrains during deformation at elevated temperatures by Chang and Grant.'" In general, there are two schools of thought on the subject. One, according to Wood et al.,5 is that subgrain formation is a mechanism of deformation which is operative under certain conditions in the same way that the slip process is the mechanism of deformation which is operative under other conditions. The boundaries between the subgrains undergo a viscous flow which contributes substantially to the deformation of the material. The second, according to Cahn,13 Wyon and Crussard,10 and Chang and Grant,18 is that subgrain formation is the effect of simultaneous deformation and annealing and is,

Jan 1, 1953

By Thomas C. Wilder

The activities of both components and the partial and integral molar thermodynamic properties of mixing for the liquid Al-Ge system at 1200°K and for the gertnanium-rich Al-Ge liquidus have been determined from data for eighteen alloys of compositions in the range 0.0593 < 0.880 using the reuersible gal-vanic. cell in the temperature interval 9320 to 1258°K. The liqui-dus compositions above 93 2 °K loere also ve determined by observing the discontinuities in the C us T plots for the high-melting alloys. This system shows moderate negative deviation from ideality throughout, the values for y° being 0.212 and 0.189 for aluminum and germanium, respectively, at 1200°K. Pavtial molar Properties of aluminum on the germanium-rich solidus and at infinite dilution in Ge(s) oboue 932°K were estimated from the foregozng measurements and the equlibrium data of previous investzgators. RECENT compilations of data1" have shown an increasing demand for knowledge of the thermodynamic properties of mixing of metallic alloy systems. In the case of binary-liquid systems where one of the components is a semiconductor this information is useful because, primarily, properties of the second (dopant) component on the liquidus, solidus, and at infinite dilution may be determined more accurately than from calculations based on the phase diagram. In this investigation a reversible galvanic cell was used to determine the chemical potential of aluminum in the two-phase region, liquid + [Ge], on the germanium-rich side of the A1-Ge system in the temperature range 932" to 1193°K. In addition, similar measurements for homogeneous liquid A1-Ge alloys for the entire composition range were obtained for the temperature interval 932" to 1258°K. The cell used was: The experimental technique and the treatment of the data were essentially the same as described earlier394 and are elaborated upon only briefly here. Each cell consisted of a liquid aluminum anode and three A1-Ge alloy cathodes of different composition which were held in Morganite alumina crucibles. The alloys were made up from aluminum and germanium weighed to the nearest 0.1 mg to a total weight of 5 to 10 g. Aluminum was a gift of Aluminum Co. of America and had a purity of 99.995+ pct. Germanium of transistor grade was a gift of Bell Telephone Laboratories. The four electrodes were contained in a larger alumina crucible which also held the prepurified fused chloride electrolyte. Contact to the electrodes was made by tantalum wire leads sheathed in alumina. The tantalum leads were centered in the electrodes by suitable positioning of an alumina radiation shield which fitted on the top of the - alulnina crucible. Two chrome l-alumel thermocouples, sheathed in quartz wells, completed the internal cell arrangement. The entire assembly was enclosed in an alumina tube, fitted with a water-cooled copper head so the system could be evacuated and then flushed with purified argon. *

Jan 1, 1967

By David Scott

THE MOGOLLON mining district, New Mexico, has received little public attention, although for 15 years it has been the leading silver producer of the state; it is situated in a region remote from the principal lines of travel, and its activities have usually been limited to the operations of two or three companies. The value of the total production of the district in the 44 years of its history has been estimated at $15,000,000. For the years 1904 to 1917, inclusive, the output was: gold, $4,370,000; silver, 10,042,000 oz.; copper, 874,862 lb.; total value, approximately. $10,500,000. In 1913 the district contributed 80 per cent. of the total silver production of New Mexico, but in 1917 only 41 per cent., due to serious interruption in the operations of the leading producer. Since 1914 the silver output has diminished one-half, and the present high value of silver is nearly offset by the increase in cost of production. The output of gold has rarely exceeded 35 per cent, of the total for New Mexico. The ratio of silver to gold, by weight, has averaged 46:1 based on the whole output of the district. LOCATION AND TOPOGRAPHY The town of Mogollon is 75 mi. (121 km.) by a poorly located highway from the nearest railroad terminals, at Silver City and Tyrone. All supplies are transported by motor trucks and teams. The area, sometimes called the Cooney Mining District, lies on the western flank of the Mogollon Mountains, which occupy the western part of Socorro County. The elevations drop steeply on the west to the valley of the San Francisco River, adjacent to the Arizona boundary. The topography is very rugged, the whole area being sharply dissected; deep canyons with steep gradients and rugged walls are characteristic of the whole western-slope of the Mogollon Range. The main canyons run east and west, and usually maintain a flow of water during the entire year. As would be expected in a region of such deep dissection, the

Jan 2, 1920

By Bailey Willis, George Otis Smith

I. Summary of General Features. Location.—The Clealum iron-ore deposits occur on Clealum river, a tributary of the Yakima river; in the eastern spurs of the Cascade range, Washington.† Mount Stuart, 9470 feet in altitude, is a dominant peak of the district, which will therefore be referred to as the Mount Stuart district. By way of the valley and cañon of the Clealum, the ores are 18 miles from Roslyn, the colliery-town, which is reached by a short branch from the Northern Pacific Railroad. Where they occur the valley has an elevation of 2900 to 8000 feet above sea; that of the end of the branch railroad at Ronald is 2345 feet. The grade of the valley from near Ronald to the junction of the Clealum and Salmon Lasac rivers, 144 miles, is 20 feet per mile; thence to the iron-ores it is 130 feet per mile, through a cañon 241/2 miles long. Abreast of the deposits the western wall of the valley is formed by precipices of sandstone; the eastern slope is comparatively gentle, being cut in easily eroded

Jan 1, 1901

By Frederick T. Fischer

INTRODUCTION Post-Lower Ordovician karstification on a continental scale produced a wide-spread paleoaquifer in the upper portion of the Knox Group of the Southeastern United States. The presence of economic zinc deposits in the Knox of Tennessee is considered to be a con- sequence of this paleoaquifer(1). During The New Jersey Zinc Company&apos;s initial exploration of the middle Tennessee region the known artesian nature of modern Knox water and its potentially adverse effect upon mining activities was a matter of concern. This concern intensified as a mining situation appeared imminent and a program of hydrologic investigation was begun in early 1969 and continued through August 1972. The preliminary findings of this work were reported at the AIME World Symposium on Mining and Metallurgy of Lead & Zinc in 1970(2). This paper presents additional data acquired during subsequent stages of the program and relates the hydrologic relationships to the overall geologic framework of the area. PHYSICAL GEOGRAPHY The Elmwood mine is 85km east of Nashville and 8km southeast of Carthage in Smith County, Tennessee (Figure 1). Its physiographic location is in the Central Basin of Tennessee, a basin resulting from erosional breaching across the Nashville Dome of the Mississippian strata which now form the bordering Highland Rims. Both the Central Basin and Highland Rims are divisions of the Interior Low- lands Province. Outcropping rock units of the Central Basin are predominantly Middle Ordovician limestones with scattered high hilltops capped by Devonian and Mississippian strata. One outlier

Jan 1, 1977

By Stuart S. Forbes

Changes and additions made to the Canadian Copper Refiners Ltd. electrolytic refinery between 1949 and 1955 are reviewed. The effect of high current density on current efficiency and section work is discussed. OPERATING and physical changes which have been made to the electrolytic tank house of Canadian Copper Refiners Ltd. suggest a review of present conditions. Previous papers1 a have described the general arrangement. Since then, expansion, closer anode spacing, and higher current densities have increased annual cathode capacity from 112,000 to 182,000 tons. A recent extension to the tank house, begun in the spring of 1954 and completed in August 1955, was undertaken to handle the monthly production of about 3,000 tons of anodes from Gasp6 Copper Mines. The anticipation of these additional receipts and large stocks of unrefined copper caused by the increase in custom smelting at Noranda made it necessary to increase production without immediately available additional cell capacity. Accordingly, from December 1954 through March 1955, the tank house was operated successfully at a current density of 24.0 amp per sq ft. Again, as of September 1955, one of the two tank house circuits is being operated at this high density. Although other refineries may operate at current densities higher than 24 amp per sq ft, none is doing so with anodes which contain silver and gold content as high as those being refined at Canadian Copper Refiners Ltd. General Arrangement The original building consisted of two parallel bays, each 660 ft long and 60 ft wide, with a 24 ft pump bay extending along the west side of the building. A previous expansion, completed in 1939, was to the west of the original building and consisted of two 60 ft parallel bays 240 ft long. The length of these two bays was extended in 1954 to 540 ft, adding one stripper and 12 commercial sections to No. 2 electrical circuit. Space is still available for an additional six commercial sections and one stripper section. Construction on these seven sections started in September 1955, and will be completed early in 1956. The tank house capacity will then be 206,000 tons of cathodes per year. In the two tank houses there is a total of 900 cells distributed as follows—commercial, 468; stripper, 36; total, 504 in the No. 1 tank house (No. 1 circuit): commercial, 360; stripper, 36; total, 396 in the No. 2 tank house (No. 2 circuit). Section arrangement consists of nine cells to a tier and two tiers or 18 cells to a section. Anodes, weighing 620 lb each, are cast with a Baltimore groove and are refined by the multiple system. Solution enters each cell through a bottom inlet at one end and overflows at the top of the opposite end. Rate of solution flow through the cells is controlled by valves at each section to 4.5 gpm. Electrical power to the tank house is now provided by nine 675 kw motor generator sets. Each set consists of a 135-12 v 5000 amp dc generator, driven by a 980 hp 2300 v synchronous motor. When No. 1 circuit is operated at 22,000 amp, five sets, at 4400 amp each, are connected in parallel. As the maximum allowable current on No. 2 electrical circuit has recently been set at 18,000 amp, only four sets are connected in parallel on No. 2 circuit. A tenth set, now being installed, will be reserved as a spare, for use in either circuit as required. Recent Changes In 1949, the annual capacity of the tank house was increased from 112,000 to 132,000 tons by closing the

Jan 1, 1957

By C Gunther

The classification here used is one of convenience only; it is not intended to include all known types of ore deposits. The characteristic features of the several well-marked types of primary mineralizations are described without reference to the ultimate source of their metals. The minerals of many deposits of obscure origin were probably introduced through fissures that are now healed, or are due to the migration of metals from such deposits. It is not within the scope of this book to enter into a general discussion of the genesis of ore deposits but, in view of the progress being made in our comprehension of the conditions under which ore deposits were formed, mention should be made of recent work. J. E. Spurr&apos;s two volumes, "The Ore Magmas," are recommended as crystallizing the views of those who are inclined to ascribe the origin of most ore deposits to a differential precipitation from magmatic rock masses and to the migration and precipitation of the viscous, liquid or gaseous exhalations from those masses. He has especially emphasized the role

Jan 1, 1932

By J. Campbell

Various models are discussed for the evaluation of the negative pressures which may occur in solidifying materials which exhibit various deformation modes: elastic-plastic, Bingham, viscous, or creep flow. The inadequacy of the previously proposed elastic-plastic solution for solidifying metals is revealed by comparison with the more reliable creep results which are given graphically for aluminum, copper, nickel, and iron. The maximum tensions experienced in the liquid phase of solidifying spheres ranging in size from large castings to submicron powders are in the range from —10&apos; to —105 atm for these metals. THERE has been much recent interest in the negative pressures associated with the volume change on solidification and in the possibility of the occurrence of cavitation. Considering the freezing of a highly supercooled liquid, an attempt to evaluate the stresses in the liquid ahead of the rapidly moving solidification front has been made by Horvay1 on a microscale and by Glicksman2 on a macroscale. In a casting of a wide freezing range alloy, the pressure differential due to viscous flow of residual liquid through the pasty zone has been discussed by Piwonka and Flemings,3 In a previous publication4 the author has attempted to estimate the negative pressure occurring in the residual liquid of a spherical casting, employing an elastic-plastic model to describe the collapse of the solidified shell under the internal tension. An earlier model assuming a rigid shell was shown to be inaccurate by many orders of magnitude. The elastic-plastic model is critically reviewed here, and other models are developed which are thought to be more closely related to metals and other materials near their melting points. The spherical geometry (Fig. 1) is chosen because the highest shrinkage pressures would be developed, although the analyses are readily adaptable to cylindrical geometry. A parallel sided casting experiences little internal tension because of the relatively easy dishing inward of the sides. (This commonly observed phenomenon has previously been attributed solely to atmospheric pressure.) Furthermore, small regions of confined liquid in a large solidified volume of a casting approximate reasonably well to spherical geometry. ELASTIC-PLASTIC MODEL The author has shown4 that as solidification proceeds the internal hydrostatic tension builds up until the elastic limit of the shell is exceeded. At this point the internal pressure is closely -2Y/3. Subsequently a plastic zone spreads from the inner surface toward the outer surface of the shell. When the whole casting is deforming plastically a rather more generalized analysis taking account of the externally applied pressure PA + 2y/b gives the internal pressure as: P = Pa + 2y/a + 2ys/b - 2 Y In(b/a) [1] The 2y/a and 2ys/b terms result from the tendency of the liquid-solid and solid-vapor interfaces to shrink, reducing their energy, and thereby helping to collapse the solid phase and compress the liquid phase. The 2y/b term would be important only for powders. The last term arises because of the plastic restraint of the solid, resisting collapse and so effectively expanding the residual liquid. From Eq. [I] it is easily shown that there is a minimum in the pressure at the radius amia= y/Y [2] which is of the order of 103K for the metals aluminum, copper, and iron, and corresponds to the minimum pressure Pmin = 2 Y[l-ln(bY/y [3] The results of a fully worked out elastic-plastic solution are given in a previous reporL4 The main criticism which may be leveled at this analysis when applied to metals at their melting points is the strong dependence of the yield stress on the strain rate. The strain rate varies with both solidification conditions (e.g., whether chill-cast or slowly cooled) and during solidification, as is indicated in the following section. Thus an appropriate choice of Y is very arbitrary. Before proceeding to a discussion of models which are strain-rate-dependent, it is necessary to evaluate the strain rate as a function of the rate of solidification. SOLIDIFICATION RATE Various empirical relations have been deduced5 for the rate of thickening of the solid shell by pour- out tests on partially solidified spheres. These, however, are unsatisfactory for our purposes since they become very inaccurate when the liquid core is very small. A theoretical approach is therefore necessary, and some solutions are set out below. Making the assumptions of constant surface temperature of the casting during freezing, no superheat, and a material freezing at a single temperature, Adams8 deduces the approximate solution: which becomes when b » a: Employing a semiempirical approach vallet6 finds:

Jan 1, 1969

By L. S. Darken

THE manufacture and treatment of metals comprises operations whose effectiveness depends in large measure upon diffusion phenomena. The significance of such phenomena has, for a few simple cases, long been understood, but in more complex cases it has not been adequately recognized. This paper presents a mathematical analysis of some of the cases in which diffusion leads to the formation of a new phase within the metal, and this analysis provides a basis for interpreting quantitatively many apparently diverse experimental observations recorded in the literature, some of which are outlined in the following pages. OBSERVATIONS RECORDED IN LITERATURE An outstanding instance is the general type of phenomenon in which diffusion of an element into an alloy is followed by a phase change, which most frequently is a reaction (precipitation) of the diffusing element with one or more components of the alloy to form a compound. Thus in certain alloys heated in contact with oxygen not only the usual oxide scale appears but, in addition, beneath the surface, a well-defined zone in which free oxide particles are dispersed with notable uniformity. This zone, commonly referred to as the subscale or zone of internal oxidation, is remarkable in that the visible boundary between it and the unaltered metal is usually sharp. Such a subscale, which appears to have been recognized first in oxidized copper alloys, has been described and studied by C. S. Smith,1 by Rhines,2 and by Rhines, Johnson and Anderson;3 but it appears also in other alloys when they are exposed to conditions that bring about the precipitation of some compound, not necessarily an oxide. Another clear case of this same kind is the diffusion of carbon into a steel containing an element such as molybdenum, chromium, vanadium or tungsten, whose carbide is less soluble in iron than iron carbide, the result being that some part of that element is precipitated as a dispersed carbide. A similar phenomenon may occur on the welding of two alloys each of which contains one of a pair of elements that react to form a compound or a new phase of any sort. But in addition to the precipitation of a compound formed from the diffusing element, other effects may result merely from the presence of the diffusing element. For instance, if homogeneous austenite, nearly saturated with respect to carbon, is heated in contact with silicon in the absence of oxygen, one would expect to find, behind the several iron-silicon phases analogous to a scale, a zone of austenite containing dispersed carbide, because of the fact that silicon decreases the solubility of carbon in iron. As still another example, oxidation of an alloy may result in diffusion toward the surface of one or more of the constituents; for instance, during oxidation of a steel containing an element such as copper, which is less prone to oxidation than iron, there is a notable enrichment of copper just beneath the scale-metal interface. As an example of a yet more

Jan 1, 1942

By M. J. Duggin

Structural similarities between the E, X, and iron carbides are illustrated. Experimental evidence regarding phase transformations occurring during ternpering reactions in finely divided carbides, thin-film carbides, and carbides which occur in steels is considered and possible mechanisms for the E — x and x — 9 transformations proposed. HOFER1 has shown that within the appropriate temperature ranges carbon monoxide will react with finely divided a iron to form either iron carbide or x iron carbide. He has shown that at an elevated temperature the E iron carbide will transform to the x iron carbide (Hagg carbide) which, upon further elevation of temperature, will transform to 9 iron carbide (cementite). Jack,2,3 using X-ray diffraction methods, has observed that during the tempering reactions occurring in steel the E iron carbide formed in the first stage of tempering passes into two-dimensional platelets of 0 iron carbide during the second stage of tempering. The three-dimensional form of the 0 carbide is formed during the third stage of tempering. Jack suggested2 that the two-dimensional platelets of 0 carbide could be related to the faulted x iron carbide. Okada and Arata4 investigated a Swedish steel containing 1.05 wt pct C and approximately 1.0 wt pct Mn using permeability measurements at low field strength. A Curie point of 360°C was observed in the quenched steel, which indicated the presence of E iron carbide. On tempering at 400°C the specimen developed a Curie point at 230°C, indicating the presence of x iron carbide, and on tempering at 700°C the specimen developed a Curie point at 190°C which was assigned to 0 iron carbide. The carbides were extracted electro-lytically and the use of X-ray diffraction techniques4r5 indicated the carbide with a Curie point of 230°C to be x iron carbide. The Curie points of the carbides are 10 to 22°C lower than the accepted values which is probably due to the presence of manganese in the carbides, since it has often been observed (e.g., Ref, 6) that a partial substitution of manganese for iron in cementite will lower the Curie point of this carbide. Hofer&apos; summarizes additional evidence of the tempering reactions in steel in which E iron carbide, formed during the first stage of tempering, transforms to x iron carbide during the second stage of tempering. During the third stage of tempering, the x carbide disappears as the 0 carbide is formed. By carburizing thin iron films in a CO gas stream, ~a~akura&apos; has been able to produce the E, X, and 0 iron carbides. He found that below 250°C the E iron carbide was formed; between 250" and 350°C the x iron carbide was formed and above 350°C the 0 iron carbide was formed. He has shown that the E iron carbide transforms to form x iron carbide at 380" to 400°C and that the x ir°n carbide transforms to form the 0 iron carbide at approximately 550" C; both of these phase transformations are irreversible. Hofer&apos; presents a review of evidence to show that the sequence of reactions occurring during tempering processes subsequent to the formation of E iron carbide formed by the direct carburization of finely divided a iron is the same as the sequence of reactions which occur during the tempering processes subsequent to the formation of E iron carbide in steel during the first stage of tempering. It is evident from Nagakura&apos;s work that identical tempering reactions are found in thin films of iron which have been carburized to form iron carbide. The purpose of this paper is to discuss the structural similarities between the E, X, and 0 carbides and to suggest a possible mechanism by which regions of the E carbide, formed during the first stage of tempering, may transform to the x carbide during the second stage of tempering. For the finely divided or thin film carbides a mechanism will be proposed for the transformation of the x carbide to the 0 carbide during the third stage of tempering, although it will be suggested that there is evidence that such a transformation may not occur in steels. STRUCTURAL DATA OF THE E, X, AND 0 IRON CARBIDES € Iron Carbide. It is evident from X-ray diffractions and electron diffraction&apos;, investigations that the metal atoms in the E iron carbide form an hcp structure with lattice constants ah = 2.752A, ch = 4.3534, using electron diffraction, reports the lattice paramet$rs of the superlattice cell to be a = 4.767A, c = 4.354, c/a = 0.9134. He finds that the carbon atoms occupy the octahedral voids in the metal atom structure so as to form a hexagonal stacking sequence with its basal plane parallel to that of the metal atoms. Considerable long-range disorder occurs in the positioning of the carbon atoms, however, which is in agreement with the possible range of composition Fe2C-Fe3C discussed by Hofer.&apos; Barton and ale" have made X-ray diffraction measurements on a sample of E iron carbide extracted from a catalyst in an organic process. Although there were few reflections recorded on the obtained X-ray powder diffraction pattern, they have proposed that the structure could belong to one of the three possible space groups p3m1, P63/mmc, or Pbcn if one assumed the composition to be Fe2C. Nagakura, using electron diffraction data, suggests a space group of P 6322 for a specimen of c iron carbide of apparent composition Fez.&. x Iron Carbide. The x iron carbide has been studied by Duggin and Hofer" and by Jack and wild,&apos; who

Jan 1, 1969

By Charles A. Ashburner

VERY little is known of the economical value of the cod-bells of the State of Texas. The first authentic statement in regard to their occurrence is that contained in the reports of the United States Exploratians for the Pacific Railroad, near the 32d parallel of latitude, published in 1863-55. Professor William P. Biake reports, "that a number of seams of bituininorls coal, varying in thickness from two to four feet, have been opened along the Brazos River, in Young County, about one hundred and fifty miles west of Fort Worth." Dr: Shurunrd also states, " that the claracteristic fossil fornis of the Carbeiferaas Era have been found with this coal, and considers the age of the formation established. Foesils obtained from the carboniteroas limestone remove all doubt of the age of these deposits."† In the spring of 1879, I was called upon by some Eastern capitalisets to make an examination of the Brazos coal-field, in order to obtain the thickness, extent., and value of the coal which could be mined and be&apos;made merchantable fir stearn, heating, and metallurgical purposes. The demand for coal in this section of the country is great, and a fuel which in our Eastern markets might be considered of inferior quality, would here find a ready sale. It must be remernbered that the market value of a coal does not depen&apos;d upon its absoltite purity, but upon its actual value in heat units which it is capable of prodwing. A poor coal which can be cheaply milled near the consuper, is infinitely more remunerative to a mining company than a superior coal whose cost to the consumer is greatly increased by high mining charges and railroad freights. The value of the Texan coals does not depend upon their purity but upon their low first cost and nearness to a market. A glance at a geological map of the United States, will show that the Brazos coal-field is the extreme southwestern extension of what may be called the Missourian, Fourth or Western, bituminous coal

Jan 1, 1881

By K. L. Komarek

Based on theoretical and experimental evidence a discussion follows of the behavior of phosphorus -bearing iron ores in the R-N Direct Reduction Process and suggestions are made of methods of reducing the amount of phosphorus in the metallic end product. In ferrous metallurgy a direct reduction process is one in which iron ores are reduced to metallic iron with gaseous or solid reductants without the appearance of a liquid phase. A number of attractive features have induced several companies and government agencies to invest in the development of direct reduction processes. A summary of all direct reduction processes up to 1954 has been given by Barrett,&apos; and Wiberg,2 and Willems3 have reviewed the most recent developments in this rapidly expanding field. Many difficulties have been encountered in direct reduction processes and the nature of these difficulties has varied from process to process. One problem common to almost all of them is the removal of phosphorus which is one of the reasons for the rather pessimistic outlook given by some government publications4&apos;5 to direct reduction processes. In this paper an attempt is made to give a theoretical explanation of the variations in phosphorus removal observed in the R-NY Direct Reduction Process. However, many conclusions are general enough to be applicable to other processes. Most iron ores treated by the R-N process yield products lower in phosphorus than the original ore. A qualitative account of the factors has been given by Stewart, Reed, and Herasymenkoe but the erratic removal of phosphorus from some ores and the general importance of this problem make a more careful analysis of the theoretical aspects desirable. In the R-N process mixed ore or balled fines, ex-

Jan 1, 1963

By Frank R. Van Horn

It is customary to ascribe two general modes of occurrence to natural gas, namely, shale gas which, as the name indicates, is found in shale, and reservoir gas, which occurs in sandstone, conglomerate and dolomitic limestone. Both of these types are found in the Cleveland district. The shale gas has been produced on a small scale for a long period of years, probably dating back as far as 1883. Shale gas is a low-pressure gas, small in volume with variable pressure, and is limited to no definite horizon. It is generally independent of oil, may last for a long time, and is not dependent to any great extent on the structure of the rocks. There are many such wells in the district which range from 400 to 1,840 ft. in depth, although most have been completed at about 800 ft. This indicates that the wells pass through the Cleveland and Chagrin shales into the Huron or Portage shale of the Upper Devonian. During the last 2 years great interest has developed in a deeper-seated reservoir gas. What is commonly called reservoir gas is generally a high-pressure gas occurring in large volume at a definite horizon. Oil may, or may not, be associated with the gas, and in most regions in which reservoir gas is found, the geological structure is of great importance. This type of gas occurs in all large fields such as those of West Virginia which have been supplying Cleveland until the recent discovery of local gas at great depths in commercial amounts. Historical Outline The oldest well producing reservoir gas in the district was drilled in 1886 in Newburg for what was then known as the Cleveland Rolling Mill Co. This well was 3,000 ft. deep, and was thought to have reached the "Clinton" formation. Two "sands" showing small amounts of oil were recorded in the Niagara limestone at depths of 2,658 and 2,686 ft. This is about the horizon of the so-called Newburg sand which has proved to be of some importance as a source of gas and oil by recent drilling operations. The rock pressure was reported to be 400 to 500 lb. per square inch, but since the volume was only 14,000 to 16,000 cu. ft. daily, the well was not only considered unsuccessful but was thought to prove the absence of high-pressure gas in commercial quantities in the Cleveland district.

Jan 1, 1917

By H. A. Schwartz, W. Kenneth Bock

In this paper it is shown that when the tensile strength of a given steel in various states of heat-treatment is plotted against its elongation, a straight line results. The equation of this straight line can be computed with considerable accuracy from its chemical composition. The appropriate equations are given. The logarithm of the slope of the tensile-strength locus is shown to be proportional to the cumulative effect of the total alloy addition and the vosition of the line to be directly proportional to the cumulative effect of the alloy content. It is further pointed out that heat-treatment is more effective than composition in determining yield ratio. The latter enters mainly by its effect on hardenability, which is briefly discussed. Reduction of area and Brinell number are given some incidental attention. The data are applicable only to steels that have been normalized and/or quenched. The steels, if normalized, may or may not have been tempered. If quenched they must have been tempered at or above 4oo°C. (75o°F.). Introduction Cast steels vary in composition and frequently are used in various states of heat-treatment. It is obviously important to be able to predict the compositions that might accompany specific engineering properties by suitable selection of heat-treatments. For cast steels, which are of necessity produced heat by heat in accordance with the particular requirements of the castings to be poured, there has been, happily, much less tendency to standardization than for rolled products, whose destination is not necessarily known when particular ingots are made or rolled. It is of distinct advantage to the steel foundry-men to be able to make steel of given properties, using alloys that can be recovered from scrap, or most conveniently or cheaply bought, rather than a particular formula adopted in the interest of standardization. The heat-treatment appropriate to securing a given result in a given steel is well known to be closely related to composition. For example, molybdenum steels are not much softened by tempering except at rather high temperatures. Highly alloyed steels are "air-hardening," and on cooling in air behave like carbon steels that have been quenched. With these matters, we do not concern ourselves in this paper, although we recognize their importance. The entire picture evidently will be very complex and can be brought within accurate understanding only if our knowledge of test results can be coordinated in terms of general principles.

Jan 1, 1944

By H. A. Schwartz, W. Kenneth Bock

In this paper it is shown that when the tensile strength of a given steel in various states of heat-treatment is plotted against its elongation, a straight line results. The equation of this straight line can be computed with considerable accuracy from its chemical composition. The appropriate equations are given. The logarithm of the slope of the tensile-strength locus is shown to be proportional to the cumulative effect of the total alloy addition and the vosition of the line to be directly proportional to the cumulative effect of the alloy content. It is further pointed out that heat-treatment is more effective than composition in determining yield ratio. The latter enters mainly by its effect on hardenability, which is briefly discussed. Reduction of area and Brinell number are given some incidental attention. The data are applicable only to steels that have been normalized and/or quenched. The steels, if normalized, may or may not have been tempered. If quenched they must have been tempered at or above 4oo°C. (75o°F.). Introduction Cast steels vary in composition and frequently are used in various states of heat-treatment. It is obviously important to be able to predict the compositions that might accompany specific engineering properties by suitable selection of heat-treatments. For cast steels, which are of necessity produced heat by heat in accordance with the particular requirements of the castings to be poured, there has been, happily, much less tendency to standardization than for rolled products, whose destination is not necessarily known when particular ingots are made or rolled. It is of distinct advantage to the steel foundry-men to be able to make steel of given properties, using alloys that can be recovered from scrap, or most conveniently or cheaply bought, rather than a particular formula adopted in the interest of standardization. The heat-treatment appropriate to securing a given result in a given steel is well known to be closely related to composition. For example, molybdenum steels are not much softened by tempering except at rather high temperatures. Highly alloyed steels are "air-hardening," and on cooling in air behave like carbon steels that have been quenched. With these matters, we do not concern ourselves in this paper, although we recognize their importance. The entire picture evidently will be very complex and can be brought within accurate understanding only if our knowledge of test results can be coordinated in terms of general principles.

Jan 1, 1944

By G. L. Oldright

THE economic manufacture of sulfuric acid by the ordinary chamber process usually involves production on a large scale and a plant that is costly to construct. The nature of sulfuric acid makes it costly to transport any great distance. For these reasons, the metallurgist has not found it feasible, at times, to beneficiate ores amenable to leaching, and a. need exists for a local process that will produce acid cheaply on a small or large scale. To leach ores containing residual sulfides, an oxidizer, such as ferric sulfate, is needed in solution. Precipitation with scrap iron is one of the cheapest methods of removing some metals from solution, giving a plant of low first cost and supplying a source of cheap ferrous sulfate. The other ingredient needed for the process is SO2 roaster gas; the addition of which, as, described below, will give both ferric sulfate and sulfuric acid. Where roaster gas is a waste or obnoxious, product, the expense. for materials is still further lessened. The use of ferric sulfate and sulfuric acid as a solvent lends itself, well to the utilization of scrap iron as a precipitant, and the stages of the process fit in well together as an economic whole.

Jan 8, 1925

By F. E. Buch

THE Smelter is designed for a production capacity of 10,000 short tons of blister copper per month, when operating on the present concentrate grade. The Smelter lay-out is shown in Fig I. The major units of equipment comprise two reverberatory furnaces, three 13 by 30 ft Peirce-Smith converters, two straight line casting machines, one being served by a 13 by 30 ft holding furnace and the other by a ladle tilting quadrant, two converter ,aisle cranes and two converter blowers. The plant is compact and the general arrangement of standard gauge railway tracks and conveyor belts provides for a smooth flow of incoming materials and metallurgical products. Concentrate is received by conveyor belts and fluxes in standard railway trucks. The local track system is covered by an electric trolley locomotive. The Smelter treats a wet (10 pct moisture) flotation concentrate containing approximately 53 pct total copper and 0.9 pct oxide copper. The predominating minerals are chalcocite, chalcopyrite and bornite accompanied by small quantities of malachite and cuprite. The gangue is highly siliceous and requires limerock as a flux. Metallurgy would be straightforward were it not for the necessity for eliminating k bismuth which occurs as an impurity in the ore along with the copper. Directly or indirectly most of the Smelter problems can be traced to the necessity for bismuth removal. Copper recovery, based on new copper treated, averages 97.5 pct. GENERAL DESCRIPTION Flotation concentrate, containing to pct moisture, is conveyed from the filter plant to the smelter storage bins by conveyor belts, the material being weighed in transit by a revolving drum type of weigh-hopper manufactured by Samuel Denison and Son, Ltd. The weigher consists of a steel drum with dished ends carried on a horizontal shaft and rotated by an 8 hp squirrel-cage motor through a worm and spur reduction gear. A feed mouth in the drum permits of filling and discharging. The whole unit is supported on a framework resting on weighing levers, which in turn connect to transfer levers, thence to an indicator of the steelyard type situated 16 ft from the centre line of the drum. The indicator is of the "Denison" patent equilibrium controlled ticket stamping type, insuring mistake-proof records by a combination of electrical and mechanical movements which prevent the operator from printing until the cover enclosing the steelyard is closed and until the poise-weights have been set correctly to the weight of the hopper and contents. The machine is capable of weighing 30 short tons at a time but the usual load is 28 tons. After obtaining the gross weight the drum is rotated and discharged into a receiving bin situated below it. The empty drum is weighed and the net weight re-

Jan 1, 1947

By E. Bicknese, R. Clark

The mechanism and rate of reduction of FeO at conditions similar to those in the stack of a blast furnace have been determined for temperatures from 980" to 1165°C. Preliminary studies of the reduction of Fe2O3 with activated coconut charcoal in a static system (no flow of reducing gas) have shown that the CO2-CO ratio of the product gas depends upon the relative reactivities of the Fe2O3 and charcoal. In a systern with a "hot blast" of CO and Nz (simitar to dry bosh gas), synthetic FeO, and actiuated coconut charcoal, the rate of reduction was not sensitive to the flow of reducing gas, and the rate-controlling step alas the chemical reaction at the metal-oxide interface. Wherz solid carbon was not present, a critical flow rate of reducing- gas had to be met in order to prevent a lowering of the reduction rate. The effect of a less-reactive carbon (blast-jurnace coke) and of a "natural" FeO on the mechanistn and rate, and the mininum amount of carbon necessary in the charge to tnaintain the reducing potential of the gas phase, have been determined. THE importance of iron oxide reduction processes has encouraged many studies of the process reaction kinetics. Despite this, the mechanism is not well-understood and three main theories have evolved, which can be stated as follows: A) the rate-controlling step is diffusion, either gaseous diffusion of the reductant or product gas through a porous solid,&apos; or solid-state diffusion of iron and oxygen atoms through the so1id.2 B) The slow step is diffusion of reducing gas through a stagnant boundary layer. C) The reaction rate is controlled by the chemical reaction occurring at the metal-oxide interface and is proportional to the area of this interface.3 By increasing the velocity of the reducing gas to a flow rate beyond which no increase in the reduction rate is observed, critical flow rate, it may be possible to eliminate B as the slow step. However, as warnere points out, the establishment of a critical flow rate may only assure that the reaction is not limited by a reduction in the reducing potential of the gas and that B may still be the rate-determining step. Edstrom and Bitsianes and Seth and Ross8 show that A and C may both be correct for the reduction of the same oxide, depending upon the stage of the reduction, and that the relative importance of the two mechanisms varies with the porosity of the oxide. Themelis9 has derived expressions which express A, B, and C in terms of the fraction reduction, Rx, of a spherical particle. Thus, in the case of A a plot of In (1 - Rx) vs time must be linear and the time to reach a given reduction is proportional to the square of the particle diameter. For B a plot of (1 - Rx) vs must be linear and the time to reach a given reduction is proportional to the square of the diameter. For C a plot of 1 - (1 - RX)1/3 vs f must be linear and the time to reach a given degree of reduction should be proportional to the diameter. In the case of mixad controlled reactions, none of the plots are linear over their entire length. The results of previous studies, in which the rates of gaseous reduction of iron oxide were measured in the absence of carbon, may not correspond to blastfurnace practice because they ignore the effects of the Boudouard reaction. CO2 +C — 2CO The presence of carbon may alter the mechanism or the rate of iron oxide reduction through an enrichment of the gas phase by Eq. [1]. In this case, the presence of and reactivity of carbon become important. If the Boudouard reaction has no effect on the rate of reduction, the reducing gas could be supplied by some means other than the gasification of carbon at the tuyeres and carbon could, theoretically, be eliminated from the burden. Preliminary studies of the reduction of Fe2O3 with activated coconut charcoal were made to determine if the reactivity (surface area) of the Fe2O3 had any effect on the product gas composition. Two size fractions of Fe2O3 were reduced with charcoal in a static system (no flow of reducing gas). In each case the charcoal was -100 + 325 mesh and was 25 pct of the total charge. One fraction of the reagent-grade Fe2O3 was submicron in diameter. The other fraction was -100 + 200 mesh and was prepared from the former by compacting, sintering at 1300°C, crushing, and screening. In each experiment, the reaction vessel was filled with a mixture of CO and CO, which would be in equilibrium with FeO and iron at the reaction temperature. A furnace was heated to the desired temperature, the vessel was placed in the furnace, and the gaseous products of the reaction were collected and analyzed. The results of these experiments, Fig. 1, show that the gas phase associated with the submicron oxide is more oxidizing than that with the -100 + 200 mesh oxide. Therefore, in a static system, the relative rates of the reduction reaction and the gasification of carbon depend upon the reactivities of the Fe2O3 and charcoal. The reduction of FeO to iron is the most important reaction occurring in the blast furnace and is probably the slowest of the several reduction steps. The mechanism and rate of reduction of FeO in a system containing carbon and a flow of dry bosh gas have been studied. TRANSACTIONS OF THE METALLURGICAL SOCIETY OF AlME

Jan 1, 1967