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By James Douglas

Discussion of the paper of James Douglas, presented at the New Haven meeting, February, 1909, and published in Bulletin No. 29, May, 1909, pp. 439 to 451. JAMES DOUGLAS, New York, N. Y. (communication to the Secretary*) :-In my paper on the Conservation of Natural Resources, I referred to the slow replacement of bee-hive ovens by the by-product ovens as a most notable instance of waste. And I quoted from Mr. Parker's report for .1906 an explanation given by him in accounting for the small production of by-product coke. It was that the markets for the by-products of the coke-ovens was so limited that some of the ovens constructed were out of operation. His report on the manufacture of coke in 1908 1 does not record an improvement, and attributes the strange fact that we alone, of all the industrial peoples, delay the adoption of this cardinal improvement from the continuance of the same almost inexplicable cause. To quote again from his report, lie says (p. 241): "The year 1908 was not marked by any notable gain in the construction of by-product coking plants, though some new work was done. There was a net increase of 115 in the number of completed ovens in 1908 over 1907, the totals for the two years being, respectively, 3,892 and 4,007. The additional equipment consisted of 140 Koppers regenerative ovens built at Joliet, I11., by the United States Steel Corporation, but this increase was partly offset by the dismantling of Y5 Semet Solvay ovens at Sharon, Pa., the net gain being 115 ovens. Included in the total of 4,007 completed ovens in 1908 are 152 Newton-Chambers ovens at Vintondale, Pa., but as no recovery of by-products was made at this plant in 190S, the production of coke is included with that from beehive ovens. The 56 ovens of the same type at Pocahontas, Va., have not been in practical operation since they were first. installed. In addition to these there was one other by-product plant of 120 ovens. Oat. was not operated during the year. The number of retort ovens producing coke in 1908 was 3,679, as compared with 3,811 active ovens in 1907." In describing the anomaly he says (p. 249): It has been contended that the development of the by-product coking industry would have shown more rapid progress if markets for the by-products were * Received Feb. 2, 1910. Mineral Resources of the United States for 1908, Part I1., U. S. Geological Survey (1909).

Apr 1, 1910

By Dwight H. Seely, Louis R. Records

A process for low-temperature dehydration of natural gas utilizing Joule-Thomson effect in expansion through a throttling orifice has been tested in a full-scale field installation. The results of these tests are presented in the form of performance curves from which the process may be easily evaluated. The effect of separation temperature on condensate recovery from the process is also shown. INTRODUCTION The transportation of natural gas from producing well to the consumer has always encountered the problem of hydrate prevention. This problem has become increasingly important in the past ten years due to the rapid increase in produced gas volumes, production pressures, transportation pressures and distance from producing wells to consumer. Natural gas, as normally produced from gas or gas-condensate wells, is saturated with water vapor at well-head conditions of temuerature and pressure. The solution of the hydrate problem require; but one basic process — dehydration of the gas to a water content which will result in a water dew-point below the minimum temperature to be encountered from the producing well to the point of consumption. Much of the recent development of gas and gas-condensate reserves in the Gulf Coast Area has been in locations which are accessible only by water. High well-head pressures, pipeline construction and maintenance costs and the desirability of final central gas-condensate separation facilities have stimulated the development of dehydration equipment which can be installed at each well and which will permit hydrate-free transportation of both gas and condensate in the same line to central facilities. There are four types of natural gas dehydration processes now used: 1. Adsorptive processes. 2. Absorptive processes. 3. Chemical reaction processes. 4. Refrigeration processes. The first three of these processes are indirect in that they require use of adsorbents, absorbents or reactive chemicals. These materials require regeneration and part of the total gas stream is consumed in the regenerative process. Indirect processes have a wide range of flexibility as defined by allowable operating pressure and temperature, but most are not easily adapted to automatic operation. The refrigeration process described in this paper was designed for installation at the producing well-head. It requires no regenerative cycle and with normal well-head temperatures no external source of heat. The flexibility of this process is limited only by the pressure drop which may be allowed between well-head and transportation line. THEORY There are three basic physical concepts involved in the low temperature dehydration process. These are: 1. Formation of hydrocarbon hydrates. 2. Joule-Thompson effect resulting from the expansion of gaseous mixtures through a throttling orifice. 3. The equilibrium composition characteristics of water vapor and gaseous hydrocarbon mixture.. The chemical composition and physical structure of hydrate; have been described by several investigators.3,4,5,10 Specific conditions of temperature, pressure and composition as well as the requirements for turbulence and presence of free water necessary for hydrate formation have been described by Katz.6 Natural gas hydrates, as they are found in plugged gas pipe lines, have the appearance of packed snow. The mass of these hydrates has low continuous porosity and permeability. Joule-Thomson effect. or the reduction in temperature which occurs when natural gas is throttled throusll a restrictive orifice, is the basic phenomenon which permits efficient use of refrigeration for the purpose of dehydrating natural gas. Joule-Thomson coefficients for gafeous mixture; of methane with ethane and with butane have been reported by Buder.-I~olzer, Sage and Lacey.2 Brown1 predicted temperature drops for pressure drops from enthalpy-entropy calculations. Aside from this work there were no fundamental data found which would be applicable to natural gas mixtures of varying spe-

Jan 1, 1951

By Dwight H. Seely, Louis R. Records

A process for low-temperature dehydration of natural gas utilizing Joule-Thomson effect in expansion through a throttling orifice has been tested in a full-scale field installation. The results of these tests are presented in the form of performance curves from which the process may be easily evaluated. The effect of separation temperature on condensate recovery from the process is also shown. INTRODUCTION The transportation of natural gas from producing well to the consumer has always encountered the problem of hydrate prevention. This problem has become increasingly important in the past ten years due to the rapid increase in produced gas volumes, production pressures, transportation pressures and distance from producing wells to consumer. Natural gas, as normally produced from gas or gas-condensate wells, is saturated with water vapor at well-head conditions of temuerature and pressure. The solution of the hydrate problem require; but one basic process — dehydration of the gas to a water content which will result in a water dew-point below the minimum temperature to be encountered from the producing well to the point of consumption. Much of the recent development of gas and gas-condensate reserves in the Gulf Coast Area has been in locations which are accessible only by water. High well-head pressures, pipeline construction and maintenance costs and the desirability of final central gas-condensate separation facilities have stimulated the development of dehydration equipment which can be installed at each well and which will permit hydrate-free transportation of both gas and condensate in the same line to central facilities. There are four types of natural gas dehydration processes now used: 1. Adsorptive processes. 2. Absorptive processes. 3. Chemical reaction processes. 4. Refrigeration processes. The first three of these processes are indirect in that they require use of adsorbents, absorbents or reactive chemicals. These materials require regeneration and part of the total gas stream is consumed in the regenerative process. Indirect processes have a wide range of flexibility as defined by allowable operating pressure and temperature, but most are not easily adapted to automatic operation. The refrigeration process described in this paper was designed for installation at the producing well-head. It requires no regenerative cycle and with normal well-head temperatures no external source of heat. The flexibility of this process is limited only by the pressure drop which may be allowed between well-head and transportation line. THEORY There are three basic physical concepts involved in the low temperature dehydration process. These are: 1. Formation of hydrocarbon hydrates. 2. Joule-Thompson effect resulting from the expansion of gaseous mixtures through a throttling orifice. 3. The equilibrium composition characteristics of water vapor and gaseous hydrocarbon mixture.. The chemical composition and physical structure of hydrate; have been described by several investigators.3,4,5,10 Specific conditions of temperature, pressure and composition as well as the requirements for turbulence and presence of free water necessary for hydrate formation have been described by Katz.6 Natural gas hydrates, as they are found in plugged gas pipe lines, have the appearance of packed snow. The mass of these hydrates has low continuous porosity and permeability. Joule-Thomson effect. or the reduction in temperature which occurs when natural gas is throttled throusll a restrictive orifice, is the basic phenomenon which permits efficient use of refrigeration for the purpose of dehydrating natural gas. Joule-Thomson coefficients for gafeous mixture; of methane with ethane and with butane have been reported by Buder.-I~olzer, Sage and Lacey.2 Brown1 predicted temperature drops for pressure drops from enthalpy-entropy calculations. Aside from this work there were no fundamental data found which would be applicable to natural gas mixtures of varying spe-

Jan 1, 1951

By Parke A. Dickey

Potential differences between strata of shale and sandstone have been recognized for about years, and they form the basis of the electrical logging of oil wells. Hitherto these potentials have been ascribed solely to electrochemical reactions caused by the disturbing effects of the water in the drill hole through which they are generally measured. Observations by the author in wells empty of water and in a mine shaft suggest that potential differences between sandstones and shales are natural and specific properties of the rocks, although they are modified in measurement by the disturbing effects of the water in the drill hole. The cause of these potentials probably is to be sought in the relative polar adsorptive capacities of quartz and clay particles. Introduction The existence of potential differences in the surface of the earth has been known for some time, and their measurement has facilitated the discovery of geological discontinuities such as ore bodies. The technique of measurement has been well established.'-a In measurements in oil wells, it has been found that the potential of shales with respect to some arbitrary reference is very nearly constant in any one well, at least below the zone to which meteoric water has gained access. Sandstones and some other types of sedimentary rocks have a difference of potential with respect to shale that is negative and may attain a value of 200 millivolts or more. The difference of potential, as usually measured commercially with water in the hole, is distributed over about one foot vertically at the top and bottom contacts of the sandstones. The sharpness of the curve at the formation contacts can be improved by using a short electrode that is close to the wall of the hole. These potentials generally have been ascribed to the disturbing effects of the water in the drill hole. Potentials have been found, however, in wells in which no water was present. In the course of experiments in electrical logging in Pennsylvania, carried out by the Pennsylvania Geological Survey, observations were made of several phenomena that hitherto have not been described, to the author's knowledge, in the published literature. The potential differences across the contacts of sandstone and shale are called in this paper "natural potentials," as distinguished from the potentials caused by electroendosmosis (electrofiltration) and concentration differences, which will be discussed subsequently. Potentials in Cored Well In the spring of 1942, the author measured the potentials in an exploratory well (Day 13, near Grand Valley, Pa.) which had been cored with diamond tools. The potentials were first measured with fresh water in the hole. A null balance potentiometer was used in this and all the other measurements described in this paper. One nonpolarizing porous pot electrode, containing copper sulphate solution and crystals surrounding a pure copper elec-

Jan 1, 1944

By Parke A. Dickey

Potential differences between strata of shale and sandstone have been recognized for about years, and they form the basis of the electrical logging of oil wells. Hitherto these potentials have been ascribed solely to electrochemical reactions caused by the disturbing effects of the water in the drill hole through which they are generally measured. Observations by the author in wells empty of water and in a mine shaft suggest that potential differences between sandstones and shales are natural and specific properties of the rocks, although they are modified in measurement by the disturbing effects of the water in the drill hole. The cause of these potentials probably is to be sought in the relative polar adsorptive capacities of quartz and clay particles. Introduction The existence of potential differences in the surface of the earth has been known for some time, and their measurement has facilitated the discovery of geological discontinuities such as ore bodies. The technique of measurement has been well established.'-a In measurements in oil wells, it has been found that the potential of shales with respect to some arbitrary reference is very nearly constant in any one well, at least below the zone to which meteoric water has gained access. Sandstones and some other types of sedimentary rocks have a difference of potential with respect to shale that is negative and may attain a value of 200 millivolts or more. The difference of potential, as usually measured commercially with water in the hole, is distributed over about one foot vertically at the top and bottom contacts of the sandstones. The sharpness of the curve at the formation contacts can be improved by using a short electrode that is close to the wall of the hole. These potentials generally have been ascribed to the disturbing effects of the water in the drill hole. Potentials have been found, however, in wells in which no water was present. In the course of experiments in electrical logging in Pennsylvania, carried out by the Pennsylvania Geological Survey, observations were made of several phenomena that hitherto have not been described, to the author's knowledge, in the published literature. The potential differences across the contacts of sandstone and shale are called in this paper "natural potentials," as distinguished from the potentials caused by electroendosmosis (electrofiltration) and concentration differences, which will be discussed subsequently. Potentials in Cored Well In the spring of 1942, the author measured the potentials in an exploratory well (Day 13, near Grand Valley, Pa.) which had been cored with diamond tools. The potentials were first measured with fresh water in the hole. A null balance potentiometer was used in this and all the other measurements described in this paper. One nonpolarizing porous pot electrode, containing copper sulphate solution and crystals surrounding a pure copper elec-

Jan 1, 1944

By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By Cyril Stanley Smith

IsolatEd alloys of copper and silicon were prepared and examined by chemical methods more than one hundred years ago, but it was not until the work of Rudolfi l that the equilibrium relations were studied. The early history of the alloys was well described by Baradue-Muller 2 and need not be further discussed here. The diagram of Rudolfi, based entirely on thermal observations, showed sillcon to be soluble in copper up to 4.5 per cent. at 849" C., at which temperature there was a peritectic horizontal resulting from the formation of a ß phase with about 7.4 per cent. silicon from a and liquid with 7.85 per cent. silicon. The ß phase was believed to form a eutectic with Cu3Si at 820" C. and 9.8 per

Jan 1, 1929

By S. A. Montague

Mica can claim a considerably greater importance than would be assumed from its comparatively small dollar volume, which came to about $37,000,000 for the United States industry as a whole in 1957. Mica is one of the strategic minerals. We must depend on imports from distant sources for virtually all of our requirements of high grade block and all of our mica splittings. Mica is essential and indispensable for vacuum tubes and high-performance condensers, two electronic components which are vital military necessities besides being nearly indispensable to civilization today. Composition and Properties Mica is the general name for a group of some nine different minerals, two of which, muscovite and phlogopite, are the minerals used by the mica industry as its raw material. Several of the other varieties are commercially useful-vermiculite, * used for heat insulation in expanded form, and lepidolite, used as an ore of lithium while the others-biotite, roscoelite lepidomelane, paragonite and zinnwaldite have little or no commercial importance. Biotite frequently occurs as an undesirable impurity in muscovite. Table 1 lists various properties and other data concerning muscovite and phlogopite. Chemically, mica is a complex silicate of sodium, potassium and aluminum. Most varieties of muscovite are higher in sodium, and of phlogopite in magnesium. There are no important uses of mica where the chemical analysis is important, except that in some uses of ground mica, the content of iron oxide present as an impurity must be kept to a very low limit. Muscovite occurs in a range of color from the so-called India "ruby" which is more closely a pinkish brown, to light and dark green, with numerous other intermediate shades. Ruby color is usually preferred by industry, especially in the better qualities. When split very thin the color in most [ ] micas disappears. Muscovite mica is frequently found containing black and red "stain" as a homogeneous part of the books or sheets. In most cases this stain or impurity is magnetite

Jan 1, 1960

By S. F. Shaw

The Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escal6n, Chihuahua; also about, 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season. Vegetation is scarce, aside from scanty scrub oak and other brush in the mountains, and a few mezquite, locust, pepper, and cottonwood trees

Jan 1, 1923

By S. F. Shaw

The Sierra Mojada mining district is situated in western Coahuila, about 8 km. east of the Chihuahua state line, and about one-half way from the northern to the southern extremity of the state. It is at the terminus of the Mexican Northern R. R., 125 km. northeast of Escal6n, Chihuahua; also about, 240 km. due west of Monclova, Coahuila. The altitude is approximately 1500 m. above sea level. The Sierra Mojada valley is about 10 km. long, from east to west, with a width of 1 to 2 km. It is approached from the east through the Puerto del Oro, where the Mexican Northern R. R. enters the valley; the slope from west to east is gentle. The Sierra Mojada, of which about 300 m. is an almost vertical wall, bounds the valley on the south side; on the north side, the slope to the crest of Sierra Planchada is more gradual, rising only 200 or 300 m. above the valley. Water is relatively scarce in the district, and there are no running streams. The rainy season, usually beginning at the middle of June, lasts through July, and occasionally into August or September. In some years the rains fail entirely. The slope of the ground is such that nearly all the water immediately runs off. The arroyos along the flanks of the mountains are not very deep, but in heavy rains, sometimes approaching cloudbursts, a tremendous volume of water rushes down them, carrying large boulders. A certain amount of seepage collects in the agglomerate, lying below the conglomerate, and is retained in the local fractures. Some shallow wells have been sunk in this agglomerate, and one well over 150 m. deep was sunk on the Volcan ranch, supplying about 76 1. (20 gal.) per min. A considerable supply of water is collected in large earth reservoirs in and below the town of Esmeralda. In ordinary years this supply will last until January or February, after which the Volcan well has to be depended on until the next rainy season. Vegetation is scarce, aside from scanty scrub oak and other brush in the mountains, and a few mezquite, locust, pepper, and cottonwood trees

Jan 1, 1923

By W. Chubb

By measuring the hardness of metals at temperatures just above and just below their allotropic change point, it has been established that crystal structure has a real effect upon the strength of metals. The DPH of cobalt, iron, titanium, uranium, and zirconium have been measured at temperatures up to 1000°C. It was found that the body-centered-cubic crystal structure is always the softer structure when it is involved in an allotropic transformation. The close-packed and more complex structures are inherently harder, and may be expected, therefore, to be better base materials for high strength alloys. IT has been observed that for metals with nearly the same melting point (i.e., tin and lead, magnesium and aluminum) the metal with the more complex crystal structure has a higher tensile strength and hardness. It might be asked whether this effect is really caused by the difference in crystal structure; and, if so, just what is the contribution of crystal structure to the strength of these metals. A qualitative answer to these questions can be obtained by measuring the change in hardness produced by the change in structure in metals exhibiting allotropic forms. The evidence for changes in mechanical properties during allotropic transformations is rather meager. In 1909, Rosenhain and Humfrey' observed that "ß" iron showed much less deformation at the transformation temperature than a iron. By means of a torsion test, Lee found that iron bars were "critically plastic" at the a-7 transformation temperature. Sauerwald and Knehans have shown that the dynamic hardness of iron increases between 900" and 1000°C. In 1930, Albert Sauveur' presented data on the hardness, tensile strength, and torsional strength of pui-e iron up to 1000°C. He concluded, "At 900°C, the a iron transforms into y iron, and this is accompanied by increased strength and stiffness and decreased ductility." The same year, Schischokin" obtained data on the hardness of thallium at temperatures above and below its transformation temperature. His data are replotted on semilogarithmic coordinates as Fig. 1. The fact that his data fall on straight lines in this type of plot is believed to attest to the purity of his metal and the accuracy of his results. In 1941, Nadai and Manjoine" obtained tensile data on pure iron with an indicated increase in strength at about 900°C. These experiments make it quite evident that changes in mechanical properties occur when a metal transforms from one crystal structure to another; but, except for Schischokin's data on thallium, none of the measurements seem accurate enough to determine the relative magnitude of the mechanical property change. Materials The metals that have been examined for changes in hardness during transformation include l—as- deposited commercial electrolytic cobalt about 99.7 pct pure, 2—Armco ingot iron, 3—are-melted iodide titanium of a purity in excess of 99.8 pct, 4—uranium of a purity in excess of 99.5 pct, 5—are-melted iodide zirconium of a purity in excess of 99.8 pct, 6—annealed, 0.08 pct C, rimmed steel, and 7—commercially pure RC55 titanium. While the purity of the first five of these materials leaves something to be desired, it will be noted that the observed hardness discontinuities occurred at the accepted transformation temperatures. (These temperatures are indicated by vertical arrows in Figs. 1 and 3 through 7.) The last two materials are commercial alloys introduced to show the effect of minor alloying elements upon the hot hardness curve. Apparatus Hardnesses at elevated temperatures were determined by means of a vacuum hot hardness machine. A diagram showing the basic features of this machine appears as Fig. 2. This machine is essentially a deadweight hardness .machine in a furnace within a vacuum chamber. The sapphire-tipped indentor

Jan 1, 1956

By H. E. Cline, D. F. Stein

A fine lamellar structure with interlamellar spacings ranging from 0.I to 3.7 was Woduced by high-speed directional solidification and used to study the interaction of dislocations with an array of bimetallic bound-am.es. The tensile flow properties were measured at elevated temperatures and the results interpreted in terms of an image force model. As the width of the plates decreases the strength increases according to a Hall-Petch relation, suggesting pile -ups. Considerable strengthening was also observed at elevated temperatures. In recent years composites containing a strong but brittle phase and a ductile but weak phase have been studied extensively in the search for a high-strength material with adequate ductility.' However, the strength of these composites has been limited to a volumetric average of the strengths of the component phases. In this paper we will show that a composite made by directional solidification of a Cu-Ag eutectic has strength properties that substantially exceed the strength of either of the metals in the composite, and an explanation for this increased strength will be presented. The Cu-Ag eutectic is a near ideal material to study for several reasons. The eutectic structure is made up of alternate plates of silver-rich and copper-rich phases with the same crystal structure.2'3 In addition, the mechanical and elastic properties of silver4 and copper5 are known over a wide range of temperatures and the eutectic microstructure is stable to nearly the melting point.6'7 Therefore, the properties of the eu-tectic are readily comparable to various theories involving the mechanical properties of copper and silver. The experiments consisted of producing directionally solidified Ag-Cu eutectic material, determining the structure and performing tensile tests at different temperatures and strain rates. EXPERIMENTAL A) Solidification and structure. A cylindrical ingot 2.2 cm in diam and 15 cm long was prepared from 99.999 pct pure materials and cast in argon. The ingot was placed in an alumina crucible and was direc-tionally solidified at 7 x 10"4 cm per sec in a Bridg-man apparatus in argon. Metallographic examination at both ends and along the length of the ingot showed a uniform structure that consisted of fine alternate plates of silver- and copper-rich phases. The plates were aligned parallel to the growth direction, as shown in the longitudinal section, Fig. 1, and were in small randomly oriented domains of parallel plates as viewed in a transverse section, Fig. 2. Four smaller ingots 0.175 in. in diam were solidified at speeds of 2Xlo-', 4.4 xlo-', 4.4 x 10-3, and4.4x10-4 cm per sec to produce a range of lamellar spacings. Replica electron micrographs were taken to resolve the individual plates as shown in Fig. 3. The copper-and silver-rich plates in the larger ingot were about

Jan 1, 1970

By O. D. Sherby

In 1938, Kanter' revealed that the steady-state creep rate of low-carbon iron alloys could be correlated by an activation energy expression, where the activation energy for creep, Qc, was found equal to about 90.0 kcal per mole for most of the alloys investigated. He suggested that creep at high temperatures might be controlled by some sort of solid self-diffusion process since the value of Qc was about equal to the known value for self-diffusion, Qd. Correlations were not further attempted along these lines until many years later, when new evidence2-8 was presented suggesting that Qc = Qd for many metals. This equality now appears to be established for ten metals (Al, Pb, Ni, Mg, Cd, In, a Fe, y Fe, Cu, and Au). This experimental fact prompted several investigators to postulate various mechanisms of dislocation motion which would yield an activation energy for creep equal to that for self-diffusion.7-9 Possibly the most accepted theory is that based on dislocation climb7 where a dislocation is envisioned to surmount a barrier by an atom-vacancy exchange process, thereby "climbing" from one slip plane to another. Such a model would suggest that the steady-state creep rate, i, should be directly proportional to the rate of self-diffusion, D, for a given creep stress. In order to more clearly reveal the relationship between creep and diffusion, and to eventually determine the correct model, it would be desirable to obtain data showing correlations between i and D, rather than with a comparison of the temperature coefficients, Q. It has been known for some time that the self-diffusivity of iron atoms is greatly decreased when body-centered-cubic (a) iron transforms to face-centered-cubic (y) iron. This has been ascribed to the more close-packed structure of y iron. The diffusivity ratio at the transition temperature is Da/Dy =350. Correlations of creep data for a and y iron5 reveal that the creep rates under a given stress at the transition temperature differ by about the same ratio (ea/ey 2 200). It would be difficult to reconcile these results on any other basis than that the diffusivity of atoms probably controls creep of iron in some very direct way. No other published data on other allotropic metals appear currently available for further checking such a possible correlation between i and D. Thallium transforms from a hexagonal close-packed (a) structure to a body-centered-cubic (ß) structure at 230°C (503°K) and the self-diffusivities of the two structures have been determined by shirn.10 His results are plotted in Fig. 1 where it will be noted that Dß/Da = 25 at the transition temperature. It would appear desirable, therefore, to determine the creep rates of polycrystalline a and ß thallium at the transition temperature, as well as determine

Jan 1, 1959

By John Alden

A CONSIDERABLE PROPORTION of the tonnage of aluminum used today has at some stage during its manufacture, been rolled. I. For one, therefore, was particularly pleased to hear that this Society was to hold a symposium on rolling of nonferrous metals. Metallurgists can well afford to direct their close attention to the metallurgy involved in this important operation. To one who has seen today's high production rolling mills for aluminum it is difficult to realize that the first aluminum rolling mill For sheet was installed a scant 55 yr ago, in 1892. This mill was a three-stand train of 2-high mills, driven by a steam engine and was operated for many years successfully rolling aluminum sheet. Mills for the rolling of aluminum rod were installed in 1899 to meet the demand For manufacture of electrical conductor wires and cables. Bars and rods in straight lengths were also made. While these mills were the first built for rolling aluminum products of these types some rod had previously been rolled on brass and copper mills. Not until many years later, in 1929, however, Were facilities provided for the rolling of structural shapes, such as I-beams and channels. Growth of the aluminum sheet business and the necessity for economical manufacture soon brought the realization of the economies resulting From-the rolling of sheet in long lengths and coiling it. A five-stand continuous mill driven by a steam engine, was in operation late in 1907. This took aluminum slabs coating from

Jan 1, 1948

By L. B. Gittinger

Sulfur is a nonmetallic element widely distributed in nature. It constitutes 0.06% of the earth's crust but only a very small portion occurs in sufficiently concentrated amounts to justify mining. Sulfur occurs in practically all animal and plant life. It constitutes approximately 0.09% of the elements in the oceans; it has been found in meteorites. Sulfur was known and used by man before recorded history. The American Chemical Society approved spelling for the element is sulfur. The English spelling sulphur is used commercially in the United States. In ancient times, sulfur was called brimstone, literally "burning stone." Today the term brimstone is used interchangeably with the term elemental sulfur. Sulfur is found naturally in the elemental form in subsurface deposits associated with gypsum and anhydrite in salt domes and sedimentary formations in evaporite basins and in solfatara-type deposits associated with volcanoes and mineral springs. Sulfur occurs also in molecular combination in ferrous sulfides (pyrites and pyrrhotite) and nonferrous sulfides (copper, lead, zinc, and nickel), and in mineral sulfates (gypsum and anhydrite); as hydrogen sulfide contaminant in natural gas; as organic compounds in crude oil and tar sands; and as pyrite and organic compounds in coal and oil shales. Sulfur resources are abundant and exist throughout the world but the extent to which they can be classified as reserves is greatly circumscribed by prevailing prices and technology. Estimates of world sulfur reserves are compiled by the U.S. Bureau of Mines. A compilation of reserves by area and source of sulfur published in 1970 and presented here as [Table 1] totaled 2.47 billion tons (Lewis, 1970). The effect of the decline in prices which has occurred since the earlier estimate is dramatically illustrated by the 1972 estimate of the U.S. Dept. of the Interior which shows world sulfur reserves of only 1.2 billion tons (Anon., 1972d). Sulfur is produced commercially from one or more sources in nearly 70 countries of the world. World production of sulfur in all forms totaled 41.6 million tons in 1971. (Sulfur statistics given in this chapter are long tons.) Native deposits, sulfides and oil and gas contributed, respectively, 31, 41, and 25% of world production (Table 2). Of the sulfur produced from native deposits, salt domes accounted for 54% and evaporite basin deposits, 44%. Volcanic deposits are of little significance except for local consumption. The past two decades have seen important shifts in the world's sulfur sources. In 1950, native deposits and sulfides each supplied about one-half of the world's production. During the 1950s, sulfur recovered from oil and natural gas grew rapidly, representing about 10% of the total by 1960. Since then, the petroleum industry has continued to increase its relative importance as a source of sulfur, representing more than 30% at 1972 year-end. Sulfur is generally classified as elemental or nonelemental for statistical purposes. Elemental sulfur is sulfur produced in the pure, uncombined form. It includes production from native deposits, as well as that recovered in the elemental form from oil and natural gas or other sulfur-bearing materials. When produced from other than native deposits, it is generally referred to as recovered elemental sulfur. Nonelemental sulfur is that which is utilized commercially in molecular combination with other elements, such as sulfides or sulfates. Elemental sulfur is being produced from salt dome deposits in the Gulf Coast region of the United States and the Isthmus of Tehuantepec in Mexico, and from evaporite basin deposits in west Texas, Poland, Sicily,

Jan 1, 1975

By Robert M. Dreyer

Population growth in industrialized economies constitutes an automatic stimulus for expansion of the construction and chemical processing industries, which are a big market for industrial minerals. Of the total value of mineral production in the United States, excluding fuels, about 70 % results from the production of industrial minerals. The value of industrial mineral production rose more than 10 % between 1961 and 1962. A similar growth has occurred during 1963. During the decade 1952-1962, the production of industrial minerals increased in value by 98%, in contrast to an increase of 60% in the value of the gross national product. The accompanying table shows the percentage change in the production of various industrial minerals from 1952-1962, as well as from 1961-1962.

Jan 2, 1964

By Frank L. Nason

The complete statistics of zinc-ore production in the United States for 1916 are not yet available. The following figures are, therefore, only approximate. The total production of concentrates for this year, including New Jersey and Tennessee, amounts to 1,280,000 tons. Of this tonnage, five mines produced approximately 536,000 tons, or about 42 per cent. The remaining concentrates came mainly from the "Valley States," Missouri, Wisconsin, Kansas, Oklahoma, and Arkansas. The 1,280,000 tons of concentrates represent about 25,000,000 tons of crude or run-of-mine ore. Of the five mines producing the 42 per cent., the dimensions of three are approximately 25 by 1500 by 2000 ft. (7.6 by 457 by 610 m.) or more: Four of the five mines are undoubtedly veins in the common acceptance of the term. They are located in great vein systems. The mines of "Valley States" have not, so far, been classed as veins; simply as "secondary deposits." The origin of these secondary deposits has been a warmly debated subject. Many geologists contend that they are the results of leaching from overlying and adjacent rocks carrying but traces of zinc, these traces leached out and deposited in favorable places. If this theory is correct, deposition is strictly limited to shallow depths. No volume of ore comparable to that of "true fissure veins" is to be expeeted. Just what this means to the future of zinc mining in these States is here indicated. The total zinc-bearing areas of these States amount to about 9124 sq. miles (23,631 sq. km.). Assuming that 10 per cent. of this total will be more or less productive, there are 912 sq. miles (2,362 sq. km.) of "mineral" ground. The average depth of the operated mines is something like 100 ft. or less. In Bulletin 606, U. S. Geological Survey (1915), p. 202, Siebenthal makes the following statement: "The writer is informed by William Waugh, one of the drillers of the Stone City well, that cuttings from other wells which he drilled in the vicinity of Pittsburgh, Kan., have shown galena and sphalerite taken from a depth of 591 ft. (180.14 m.) and that the showing of ore at some places would be considered good enough to justify the sinking of a shaft had it been found in the Joplin district and at shallower depths." Leaving out of the question the prohibitive cost of such a shaft, there is

Jan 1, 1918

By T. F. Mueller, P. A. Witherspoon

For the case of an infinite radial system operating at constant terminal rate, the reservoir engineer often uses the "point source" solution of the diffiusivity equation to study pressure interference effects. At early times and at short distances from the inner boundary these solutions are invalid. The amount of error is often not precisely defined because of mathematical difficulties. Work presented here shows that, if dimensionless time is defined appropriately, previous solutions of the pressure equation can be displayed .as a family of curves on one chart. These solutions include the point source solution (referred to in the field of hydrology as the Theis solution) and other solutions obtained with digital computer methods. With these curves, an exact evaluation of the pressure drop within a reservoir or an aquifer can be made by the engineer. Examples of field problem solutions are presented. In most reservoirs the error involved when the Theis solution is employed is often negligible; whereas, in the calculation of interference effects in an aquifer, a substantial error can occur through such an approach. INTRODUCTION Flow equations are used in petroleum engineering to study the behavior of individual wells and reservoirs. In the case of wells, the pressure response at the wellbore face is the major point of interest; whereas, in the case of reservoirs, the pressure response at the interface of the aquifer boundary is sought. To aid in such studies, the flow equations have been solved in terms of the behavior at these two inner boundaries. Only limited work has been published in regard to the pressure conditions away from these points, i.e., within the reservoir or aquifer. Theis and Mortada are among the few who have reported on this problem. The Theis approach employs the exponential integral and is valid for pressure conditions that occur some distance away from the flow disturbance. It is derived from the concept of a point source, as opposed to a flow across some finite area. The Mortada results, on the other hand, are valid at all points within the reservoir or aquifer. They are presented in terms of dimension less ratios of the radius where the pressure is desired to the radius where the flow rate is measured. Their main use, in the past, has been in aquifer studies. The published results are presented in the form of graphs that are limited to a maximum radius ratio of 64. These graphical results are cumbersome to interpolate at non-integral radius ratios, so that one may be forced to utilize a rather involved analytical expression presented by Mortada. BASIC EQUATIONS The solutions of Mortada and Theis are both based on the diffusivity equation as applied to the case of an infinite radial system subject to a constant terminal rate. The equation is obtained by combining the material balance equation with Darcy's flow equation. The assumptions implicit in the use of this equation are as follows: (1) a single fluid is present that occupies the entire pore volume; (2) the reservoir is horizontal, homogeneous, uniform in thickness, and of infinite radial extent; (3) compressibility and viscosity of the fluid remain constant at all pressures; and (4) fluid density obeys the equation Using the diffusivity equation in situations where the above conditions do not hold will result in errors. These errors (not discussed here) but only the errors which arise in the solution of the equation itself. The diffusivity equation for the homogeneous reservoir conditions cited above can be written in cylindrical coordinates, as To obtain a dimensionless equation, so a single solution can be used for applications of different porosity, permeability and fluid properties, the following transformations are usually made: After these transformations are made, Eq. 3 .can be written in dimensionless form, as MORTADA SOLUTION One solution of Eq. 6 has been given by Mortada.

Jan 1, 1966

By O. J. Hassel, W. T. Maidens, J. H. Calbeck

The rotary gas fired reheating furnace used by the American Zinc Oxide Co. at Columbus, Ohio for Therotarygasfiredreheatingfurnacerefining lead-free zinc oxide is described. The outstanding features of this operation are that the color of the zinc oxide is greatly improved, sulphur is eliminated, and cadmium arethatrecovered without densifying the product to an objectionable degree. IN 1919 Leland S. Wemple obtained a patent for a process of reheating zinc oxide wherein the "coarsening of grain due to excessive heating was avoided." He taught in his specification that if solid carbonaceous material, such as lamp black, was added to the zinc oxide in proper amounts prior to reheating, objectionable sulphur compounds could be removed and the color would accordingly be improved and no objectionable densification would occur because of the relatively low temperature required. The situation that made this invention imperative was the newly opened zinc oxide plant of the American Zinc, Lead & Smelting Co. in Hills-boro, Ill. This was one of the early Western Type American Process zinc oxide operations. Characteristic of all of these early Western operations using Tri-State and Western ores was the great difficulty encountered in obtaining a product low enough in sulphur to compete with the Eastern Type American Process zinc oxides which were made from ores containing very low sulphur percentages. Wemple demonstrated that the refining process of his invention produced a superior color and although this was true and a most welcome feature, the primary purpose of the early refining operations at Hillsboro was to reduce substantially the high sulphur content of the crude zinc oxide. Although many and varied attempts had been made for refining zinc oxide none of the processes had a commercial history of any consequence until Wemple's invention became standard practice for the American Zinc, Lead & Smelting Co. in 1919 and their operations have been unique in that substantially all of their lead-free zinc oxide has been reheated since the first installation at Hillsboro. This process has become known in the industry as refining. The furnace developed by Wemple and continued in use by the company from 1919 until 1943 was unusual and merits some consideration by way of review in this paper. The furnace was essentially a double hearth coal-fired muffle furnace with a mechanical raking system consisting of a central shaft supporting six rabble arms in each muffle. The untreated or "crude" zinc oxide was fed onto the outer rim of the top muffle, moved to the center where it dropped to the lower muffle and progressed to the outer rim where it was discharged into an alloy screw conveyor. The retention in this furnace was extremely short, about 5 min, and the shallow zinc oxide bed on the hearths of the muffles was being continuously turned by the fast moving rabbles. Soft coal was burned on the grates below the lower muffle and the long yellow flame necessary to carry the heat around both muffles resulted in a very inefficient combustion of the fuel. The temperature of the top of the lower muffle seldom exceeded 65 °C although the oxide itself often reached 700°C before discharge. The capacity of this furnace was approximately 1/2 ton per hr. In our plant at Columbus it was necessary to keep four of these furnaces running in parallel to take care of the production because, as mentioned above, every pound of zinc oxide produced during these 24 yr passed through one of these refining furnaces. An essential part of this refining operation was the use of carbonaceous material admixed with the zinc oxide fed to the furnaces. Between 1 and 2 pct of a bran produced in the processing of cotton seed was added to all zinc oxide charged to the furnaces. The bran ignited on the top hearth and was still burning when the charge fell from the top hearth to the bottom hearth making a cascade of sparks. The rapid turning of the zinc oxide caused these particles of bran to flash on the hearths behind each rabble; but the combustion, of necessity, had to be complete by the time the charge reached the outer rim of the bottom hearth, otherwise the finished product would be contaminated with the charred particles of bran which would give the zinc oxide an unsatisfactory color. Although this operation was initiated to reduce objectionable sulphur percentages, as time went on new properties of the product were appreciated which made advisable continuing the refining process long after other methods of sulphur reduction became known in the industry. The particle size and particle size distribution, the absence of colloidal fines and perhaps a unique surface condition gave this product an outstanding performance when used in paints. The Wemple furnaces installed in Columbus in 1919 had to be rebuilt frequently and were extravagant in the use of fuel. The raking mechanism and the muffles required excessive maintenance expense and as the furnaces wore out the problem arose whether to continue along this line or to explore the possibilities of obtaining similar or better results in the simpler and more commonly used rotary furnace. To this end special research was initiated in 1941 on a small laboratory rotary

Jan 1, 1951

By A. N. Winchell

In connection with law suits between mining companies at Bingham, Utah, a few years ago, the writer made petrographic studies of more than 1400 rock and mineral samples in thin sections, and also careful studies of their field relations. In petrographic studies, even when an area is studied intensively, attention is commonly centered very largely on the unusual features of special interest, so that the relative abundance of rock types (or minerals or textures) can only be determined by a study of map areas outlined largely by field methods, and cannot be based directly on microscopic work. It is very uncommon, and usually impossible, to take samples at regular short intervals along and across formations. It is precisely because such methods were used at Ringham that the work presents a rare opportunity for determining, on a microscopic basis, the relative abundance of rock types and the continuity of gradations between rock types. At the same time, a study was made of the alteration of sediments under the influence of igneous intrusions, with results that are believed to be of interest and importance. • Sandstone-limestone Gradation The sedimentary rocks of the Bingham district are chiefly sandstones, with some beds of limestone, all now lying with their strike nearly east and their dip nearly north at an angle of about 30°, near the surface. The limestone beds are remarkably irregular in thickness in some places, but usually change very slowly in composition along the strike. However, the most interesting results are obtained from a study of a section across the beds at right angles to the strike. In some places, such sections show the usual alternation of pure sandstone with nearly pure limestone, in the simple manner assumed in most geological discussions.

Jan 1, 1924