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By E. Northcott, I. M. LeBaron

Before describing the electrostatic processing of feldspar, it might be well to review some of the basic definitions and terminology of feldspars. The feldspar minerals constitute a group of alumino-silicates of potassium, sodium, and calcium. Barium feldspar sometimes occurs naturally but is very rare. Hardness varies between 6 and 6.5 and specific gravity between 2.5 and 2.8. Color is generally white or pale shades of red, yellow, or green. The approximate chemical composition of the principal feldspars is given in Table I. The albite (sodium aluminum silicate) and an orthite (calcium aluminum silicate) feldspars are the end members of a series called plagioclase. These two molecules form a complete solid solution series ranging from pure soda feldspar at one end to the pure lime feldspar at the other end. Intermediate solid solutions are known as oligoclase, andesine, labradorite, and bytoconite. The general structure throughout this series is the same. Sodium and calcium may replace each other and silicon and aluminum may replace each other in the structure.

Jan 10, 1958

By F. J. Meringer, C. W. MacGregor

Various investigations have been carried out to determine the effects of cold-rolling on the common physical properties as represented by the yield strength, tensile strength, percentage of elongation and ordinary reduction of area. Very little information is available in the literature with reference to the effects of cold-rolling on the true stress-strain properties. Since the ordinary physical properties base both the stresses and the strains on the original dimensions of the test piece, which are greatly changed during the test, they are essentially empirical values and do not represent physically either true stresses or true strains. Consequently, they do not give an accurate picture of the effects of different conditions, both mechanical and metallurgical, on the strength and ductility of the material. It is not, however, the purpose of this paper to review the various advantages accruing from the use of true stress and true strain values, since these have been shown elsewhere,1-l2 but to utilize them in representing the various effects considered. The true stress S and true strain (e = q') values mentioned above for the tension test are defined by1 S =1/A and where P, A, Ao are the axial load, the instantaneous area and the original area of cross section, respectively. From simultaneous readings of the axial load and the dimension or dimensions determining the instantaneous area of cross section, the true stress-strain curve is constructed by using the relations given in Eq. I. It is then the object of this paper to discuss the general effects of cold-rolling on the true stress and strain values for a low-carbon steel together with the effects of age-hardening and directionality on these properties. Preliminary Investigations The material considered throughout the paper is a low-carbon steel of the following chemical analysis: C, 0.19 per cent; S, 0.118; P, 0.092; Mn, 0.85; Si, 0.01. The stock was received in bars, 7 by 3/4 in., and was first annealed for one hour at 1650°F. followed by a furnace cool. Photomicrographs of this material showed considerable directionality even in the annealed condition. In view of the possible effects of the nonhomogeneity and directionality in this material, it was considered important to investigate their influence on the true stress-strain diagrams. In addition, the effect of strain-aging in this steel was also made the subject of a preliminary study. Effect of Aging on True Stress-strain Properties Since a certain time element would elapse between the cold-rolling operation and the final tension tests, it was determined to investigate the aging character-

Jan 1, 1945

By S. Nenno, T. Saburi, Y. Mizutani, M. Yomarnoto, K. Komatsu

In the equilibrium phase diagram of the Ni-Mo sys-tem1,2 available at present, intermetallic compounds (or ordered phases)ß(Ni4Mo) and ?(Ni3Mo) are known to exist to the nickel rich side. In our recent investigations on Ni-Mo alloys, however, it has been found that the quenched alloys from the high temperature region containing more molybdenum than the Ni4Mo do not decompose directly into 0 and when annealed isothermally below the peritectoid temperature, i.e., 865°C. This note is to report the existence of Pt2Mo type superlattice (possibly ordered Ni2Mo) as a metastable phase in the early stage of decomposition. Alloys containing 20.1, 22.7, and 24.4 at. pct Mo were prepared by vacuum-melting electrolytic nickel of 99.9 pct purity and molybdenum powder of 99.9 pct purity in an alumina crucible. From the resulting ingots, sheets 0.3 mm thick were obtained by forging, hot-, and cold-rolling. The sheet specimens were water-quenched from ! region and subsequently annealed for various periods of time at temperatures below the peritectoid temperature. On these specimens were made optical-microscopic and transmis-sion-electron-microscopic observations. Fig. 1- Optical micrograph of the 22.7 at. pct Mo specimen annealed for 100 hr at 700°C after quenching. (ß + ?) region, B, nucleated along a grain boundaries are invading the preexisting (ß + Ni2Mo) region, A. Details of A are observable only by electron microscopy. Etchant: 60 pct HNO3-40 pct CH3COOH.

Jan 1, 1970

By L. F. Tedsen, A. E. Flanigan, J. E. Dorn

SINCE aluminum-alloy sheet may be used occasionally at moderately elevated temperatures, the effects of temperature en the mechanical properties are of interest. Recently the short-time tensile properties of several high-strength materials have been studied at temperatures up to 375°F. This paper deals with stress-rupture and [ ] creep properties at the same temperatures. The work was done at the University of California as a portion of the project NRC-548. It was financed by the War Production Board and was supervised by the Office of Production Research and Development. This paper has been released for publication by the latter agency. The following materials were studied, all in the form of 0.040-in. sheet: Alclad 24S-T Alclad 24S-T8I Alclad 24S-T86 Alclad 75S-T R301-T (clad) [ ] Specimens were loaded in tension in the cross-grain direction. Testing temperatures included 94°F., 211°F., 300°F., and 375°F. Stress levels were selected to cause rupture in times ranging from several minutes to boo hr. In each test the following data were obtained: (I) fracture time, (2) elongation at fracture, (3) the complete strain-versus-time curve (creep curve), (4) creep rate (defined in a later section). MATERIALS Materials for specimens were obtained from the manufacturers' commercial

Jan 1, 1946

By Tedsen L. F., Dorn J. E., A. E. Flanigan

since aluminum-alloy sheet may be used occasionally at moderately elevated ternperatures, the effects of temperature on the mechanical properties are of interest. Recently the short-time tensile properties of several high-strength materials have been studied at temperatures up to 3750°F.l This paper deals with stress-rupture and creep properties at the same temperatures. The work was done at the University of California as a portion of the project NRC-548. It was financed by the War Production Board and was supervised by the Office of Production Research and Development. This paper has been released for publication by the latter agency. The following materials were studied, all in the form of 0.040-in. sheet: Alclad 24s-T Alclad 24s-T8I Alclad 24s-T86 Alclad 75s-T R3oI-T (clad) Specimens were loaded in tension in the cross-grain direction. Testing temperatures included 94°F., 2II°F., 300°F., and 375°F. Stress levels were selected to cause rupture in times ranging from several minutes to 1000 hr. In each test the following data were obtained: (I) fracture time, (2) elongation at fracture, (3) the complete strain-versus-time curve (creep curve), (4) creep rate (defined in a later section). Materials Materials for specimens were obtained from the manufacturers' commercial

Jan 1, 1947

By Tedsen L. F., Dorn J. E., A. E. Flanigan

since aluminum-alloy sheet may be used occasionally at moderately elevated ternperatures, the effects of temperature on the mechanical properties are of interest. Recently the short-time tensile properties of several high-strength materials have been studied at temperatures up to 3750°F.l This paper deals with stress-rupture and creep properties at the same temperatures. The work was done at the University of California as a portion of the project NRC-548. It was financed by the War Production Board and was supervised by the Office of Production Research and Development. This paper has been released for publication by the latter agency. The following materials were studied, all in the form of 0.040-in. sheet: Alclad 24s-T Alclad 24s-T8I Alclad 24s-T86 Alclad 75s-T R3oI-T (clad) Specimens were loaded in tension in the cross-grain direction. Testing temperatures included 94°F., 2II°F., 300°F., and 375°F. Stress levels were selected to cause rupture in times ranging from several minutes to 1000 hr. In each test the following data were obtained: (I) fracture time, (2) elongation at fracture, (3) the complete strain-versus-time curve (creep curve), (4) creep rate (defined in a later section). Materials Materials for specimens were obtained from the manufacturers' commercial

Jan 1, 1947

By C. S. Barrett, A. Smigelskas

J. T. NORTON*—I think Mrs. Smigelskas Fischer has done a splendid job in working out the pole figures from rather difficult photograms which are common to beryllium. Is there not a mistake in Fig 2 in that the pole figures B and C have been interchanged? A. SMIGELSKAS FISCHER (authors' reply)—Yes, there is such an error in the labeling of the pole figures of Fig 2. The correct plane for Fig 2b and 2c is the plane in parenthesis above the figure numbers and not that in the figure subtitle. J. T. NORTON—Also, I would like to mention another method of obtaining the data for pole figures which would be particularly applicable to this problem. It is a method which has been published only

Jan 1, 1950

THE translators wish to record their appreciation of the help given by many individuals with whom they have discussed various details of the work. They are particularly indebted to Mrs. Anne Noble McKeachie, who initiated their collaboration; to Miss Cora Adamson, who spent many hours in making an accurate copy of a much-mutilated &st draft of the translation; and to the Yale University Library which gave access to its excellent collection of books on all aspects of the history of the sciences. The reader will share with the translators their obvious indebtedness to Mr. Carl P. Rollins, Mr. James W. Boyden, and the staff of the Printing-Office of the Yale University Press. The publication of this translation by the American Institute of Mining and Metallurgical Engineers has been made possible by a grant from the Seeley W. Mudd Memorial Fund, administered by a committee composed of Harvey S. Mudd, H. DeWitt Smith, and George Otis Smith. The translators are gratified that their work has been judged to fall within the scope of this Fund, which was established for the advancement of the sciences of mining and metallurgy by the encouragement of research and the dissemination of knowledge, and especially for the furtherance of such activities as might benefit the younger members of the profession. While Biringuccio's book would scarcely serve as a dependable text for the young mining student or metallurgist, it can give him a sense of his membership in a long-standing and honorable profession and enable him better to see his own work in true perspective. It is hoped that this English edition of a sixteenth-century Italian work will be read by the practicing metallurgist as well as by those who have already found pleasure in exploring the past of their profession. A man always feels more at home in a foreign country with men of his own craft than in his birthplace with those of different interests: As in space, so in time, and the modem metallurgist who may be unmoved by the literary and artistic Renaissance will quickly appreciate the spirit of that exciting period as he talks shop with Biringuccio on a visit to mine, smelter, forge, and foundry; as he sees in different forms the very furnaces and machines whose operation and response he knows so well; and as he discusses with this engineer of four centuries ago such topics as the best kinds of fuel or refractory for a given operation, and the importance of adequate supplies of power and material.

Jan 1, 1942

By O. D. A. Pease, C. D. Young, C. H. Strand

In an effort to employ cast steel of a stronger structure than that found in the annealed steel casting, the possibilities of heat treatment which will increase the strength without materially decreasing the ductulity may be resorted to.

Jan 1, 1915

By Robert Lewis

Some recent experiments in the use of compressed air for rock drills at higher than usual pressures, up to 150 lb. per sq. in., emphasize the importance of maintaining the compressed-air system in the best condition if the greatest possible over-all efficiency is to be secured. No claim of high over-all efficiency can be made for the compressed-air system of braking that is used on railroad trains, yet the air brake works effectively. Compressed air is not used efficiently in the rock drill, but no other type of machine drilling is yet a serious competitor of the air-driven rock drill.

Jan 1, 1930

By Thomas Robins

About six years ago the writer had occasion to visit a large magnetic iron-ore concentrating-plant, and then saw for the first time rubber belts employed for conveying-purposes. These belts were from 20 inches to 30 inches in width, and some of them were as long as 500 feet between centers. When I spoke of the enormous amount of material they handled with a small expenditure of power, the superintendent assented, but at the same time complained that although he bought the best quality of belts, the abrasion of the ore wore them out very rapidly, causing continually very large bills for repairs and renewals. On close examination several interesting points were discovered :

Jan 1, 1897

By J. B. Darby

In an investigation of various equiatomic alloys of transition elements, Dwightl did not find evidence for the CsC1-type ordered structure in VMn. More recently waterstrat2 has reported the occurrence of this structure in the alloy his sample had been homogenized at 1150°C and subsequently reannealed at 725°C after crushing to powder. The purpose of this note is to confirm the existence of the CsC1-type ordered structure in VMn and to report a lattice parameter. An equiatomic alloy was prepared by arc-melting under an argon atmosphere vanadium and electrolytic manganese having a purity of at least 99.9 pet. The composition was obtained by charging an excess of manganese and monitoring the weight loss until the stoichiometric composition was achieved; the assumption that the loss during melting was due to the vaporization of manganese appears to be a valid one.' The calculated composition of the sample prepared was 49.85 at. pct V and 50.15 at. pct Mn. Specimens taken from the fractured as-cast buttons were wrapped in molybdenum foil and encapsulated in quartz capsules under vacuum; there was no evidence of a reaction between the alloy and foil. The X-ray patterns were obtained using filtered copper or chromium radiation with a Straumanis-type Debye-Scherrer camera having a diameter of 114.6 mm. The CrKa radiation is best suited for detecting the superlattice lines since it overcomes the slight difference in scattering powers of the components by making use of the anomalies in atomic scattering factor which occur when the frequency of the radiation is close to the characteristic absorption frequency of one of the elements.394 A specimen in the as-cast condition, as well as one which had been annealed for 1 week at 900°C and water-quenched, gave a diffraction pattern for the disordered bcc solid solution. However, when samples were homogenized at 900°C for 3 weeks followed by a subsequent anneal at 700°C for 6 to 7 weeks and then water-quenched or furnace-cooled, the (loo), (1111, and (210) Ka superlattice lines were observed in films taken with chromium radiation. An ao = 2.904 * 0.001 was determined by a Nelson-Riley extrapolation from a film taken with CuKa radiation. The author wishes to thank Mr. J. W. Downey and Mr. L. J. Norton for carrying out the experimental portion of this investigation. This work was performed at the Argonne National Laboratory under the auspices of the U.S. Atomic Energy Commission.

Jan 1, 1963

By N. H. Harrison, J. K. Rodgers, S. Regier

This paper presents comparisons of data obtained from a laboratory reservoir study and from a calculated behavior prediction with the actual production history of a condensate reservoir. A small non-commercial discovery was depleted under closely controlled conditions and the well fluids were sampled at frequent intervals. Data on the reservoir and production variables were accumulated on a fixed schedule. A laboratory reservoir study war made using the initial well fluid samples as charging stock. The production procedures and operating conditions were held constant throughout the study wherever possible and in general paralleled the field work. The well fluid compositions and the cumulative recoveries ar a function of the reservoir pressure were also calculated using conventional flash vaporization procedures and equilibrium constants. Comparisons based on the composition of the well fluid show good agreement, the laboratory study agreeing within experimental accuracy with the field work and the calculated data comparing equally well. The gas-oil ratios are also in good agreement, but with somewhat greater deviations at the higher pressures. In the overall picture, it is believed that a model st,~tiy can predict within experimental accuracy the production history of a condensate reservoir. Better equilibrium constants for the heavier hydrocarbons are needed in order to attain improved composition accuracy by calculation. INTRODUCTION In Aug., 1955, a gas condensate well was completed in San Juan County, Utah, that was initially thought capable of good commercial production. These conclusions were derived principally from core data and electric logs, which indicated good permeability, porosity and gas content. However, after the usual series of potential tests it was found that the reservoir pressure had declined some 22 per cent, and it was obvious that the zone tapped was but a small pocket or trap. It became apparent that, with a controlled depletion of a small reservoir, a unique opportunity was available to compare laboratory and calculated studies with an actual field depletion and to further the present knowledge of condensate reservoirs. FIELD WORK The Coalbed Canyon Well No. 1 was conventionally completed in the Paradox limestone formation to a total depth of 5,912 ft. The producing zone from 5,762 to 5,806 ft was perforated with four jet shots per ft. The wellhead and field equipment were also conventional, the major items consisting of a two-pass indirect fired line heater, a high- and a low-pressure separator with the necessary controls and accessories, gas meters, back-pressure regulators, flare stacks and condensate stock tanks. The initial testing of this well con-sisted of a series of flow potential and pressure build-up tests during which some 30 MMcf of gas was produced. The reservoir pressure declined from an estimated 2,300 to 1,782 psig during this period, from which it was concluded that the reservoir was very small. In order to approach steady-state conditions in the reservoir and so provide optimum conditions for making comparisons, the field depletion was programmed to approach, if possible, constant production conditions. Bi-hourly readings were taken of the tubing pressure, the pressure and temperature of the separators, oil and gas rates, and other pertinent operating data. The gas rate, as indicated by the orifice meter, was held constant by the adjustment of the choke in the line heater. The temperature of the first stage separator was held constant by adjustment of the line heater jacket temperature. Practical considerations of production made the maintenance oi a constant gas rate impossible. The test started with a gas rate of 4 MMcf/D and a separator pressure of 250 psig. This rate was maintained until the choke was fully opened. The gas rate then declined with the falling tubing pressure and production was continued until the rate was about 2

By D. P. Kedzie, R. A. Dodd

The fatigue strength, fatigue hardening, and effect of fatigue deformation on subsequent age hardening of supersaturated Al(Cu) solid solutions have been determined as functions of alloy composition and temperature. The fatigue strength/tensile strength ratios, determined at 150°, 25°, and -195°C, decreased with increase in alloy content for all temperatures, but the F.S./U.T.S. ratios at -195°C decreased much more rapidly than did the ratios for 150" and 25°C. This suggested that strain aging and/or age hardening occurred during tests at higher temperatures. Additionally, the F.S./U.T.S. ratios at 150°C exceeded those at 25°C for all compositions, indicating greater strengthening during fatigue at 150°C. The effect of fatigue or tensile deformation at 150°, 25°, and -195°C on subsequent age hardening showed that the deformatzon increased the rate of precipitation and indicated that mechanically produced vacancies were probably formed during deformation. Fatigue hardening was studied at 150°, 25°, and -195°C, and the effect of room-temperature rests after 10 and 100 cycles was examined. The results confirmed that strain aging occurred at the higher temperatures . DURING the last 15 years various mechanisms of fatigue crack nucleation and growth based on dislocation and vacancy interactions, operating singly or collectively, have been proposed. The probable consensus of present opinion is that the fatigue process in pure metals essentially involves dislocation interactions, and that vacancies formed by such interactions play a minor or inconsequential role. However, there is some evidence that age-hardened alloys tend to overage during fatigue, probably by local vacancy-enhanced diffusion, and strain aging also might be important in selected cases. Furthermore, it has been established that the behavior of quenched-in vacancies in Al(Cu) and other solid solutions is composition-sensitive. Therefore, it seemed worthwhile to investigate various aspects of the fatigue behavior of supersaturated Al(Cu) alloys and to examine the results in terms of vacancy-enhanced effects. EXPERIMENTAL The alloys used in this investigation were prepared from 99.994 wt pet A1 and OFHC copper, the latter containing 0.04 pet 0 as the principal impurity. Six alloys were made, containing, by actual analysis, 0.58, 0.96, 1.96, 2.85, 4.45, and 5.51 wt pet Cu. They were induction-melted in air in graphite crucibles, cast as 7-in. by 7/8-in.-diam rods in graphite molds, and hot-rolled to 5/8 in. diam. The experimental work was a three-part program involving the determination of a) 10' cycle fatigue stresses as a function of alloy composition and temperature; b) the effect of fatigue deformation on subsequent aging of the supersaturated alloys; and c) fatigue hardening as a function of alloy composition and temperature. For determining the 105 cycle fatigue stresses, a portion of the 5/8-in. stock was machined into Krouse rotating cantilever beam fatigue specimens, 2 in. in length by 1/4 in. minimum diameter. These were tested at +150°, 25°, and -195°C (liquid nitrogen) on a Krouse high-speed machine, with special weights to provide lower -than-normal loading ranges, this being necessitated by the small load requirements of those alloys of lower copper content. For the high-temperature tests a small resistance heater was designed to clear the collets and fit in between the chucks, while for the low-temperature tests a hollow nylon cylinder was used, having closed ends drilled to pass a fatigue specimen, and positioned similarly to the heater. A plexiglass container completely enclosed the fatigue machine; rubber gloves fixed to ports in the walls enabled the machine to be operated from outside the box. A tray of magnesium perchlorate dried the air in the container and prevented both atmospheric corrosion fatigue at room and elevated temperatures and troublesome ice build-up at low temperatures. A total of ten to fifteen specimens was used for each combination of alloy composition and temperature. The result of each test was plotted on a standard S-N diagram, and the next stress was selected on the basis of the trends indicated by previous specimens. In this manner a small portion of the S-N diagram was constructed, and the 105 cycle fatigue stress obtained. Small Krouse fatigue specimens were also used to study the effect of cyclic prestrain on subsequent

Jan 1, 1964

By W. F. Holbrook

THE problem of sulfur control is important in all blast-furnace operations but particularly for certain grades of steel because of the rigorous specifications. During the past decade the tendency has been to produce pig iron, and, hot metal of lower sulfur content. As most of the sulfur in the ion originates in the fuel, the use of high-sulfur coke demands modifications in practice to meet sulfur specifications. While it is generally known that high temperatures and more basic slags favor desulfurization, operators as a rule produce the most acid slag that will permit proper desulfurization. The viscosity of blast-furnace slag has been thought to be related to desulfurization and has been investigated by Feild and Royster1, also McCaffery and his associ-ates2, but apparently no systematic effort has been made to determine the relative desulfurizing powers of slags over the range of composition encountered in practice.

Jan 1, 1936

By Charles D. Russell, L. H. Jenks, W. J. Leas

A detailed description is given of an experimental method for determining relative permeability of porous media to gas. Results are presented for natural and synthetic cores. The experimental data for two and three phase systems are compared. The reproduci-bility of the equilibrium gas saturation ii demonstrated and the effects due to a variation in rate of gas flow are discussed. An attempt is made to correlate total permeability and rock textural factors with relative permeability to gas. Capillary pressure curves obtained simultaneously with the relative permeability curves are shown to be equivalent to those obtained in conventional displacement cells. INTRODUCTION The advances in petroleum reservoir technology during the past decade have made increasingly apparent the desirability of a simple, rapid, reliable metliod for obtaining relative permeability data on small cores. Such data are needed in order to study fluid mechanics in porous media and for the more refined reservoir behavior prediction calculations now under development. The early experimental work in this field was done by Wyckoff and Botset1 who measured relative permeabilities for gas-liquid mixtures flowing through

Jan 1, 1950

By H. D. Yoo, M. R. Tek, D. L. Katz

The behavior of gas-storage reservoirs subject to water drive is investigated through analog simulation on an electronic differential analyzer. The simulation technique developed on an LM-10 computer permits the prediction of reservoir volume or pressure resulting from the movement of water in the surrounding aquifer. The method developed on the analog computer consists of setting up an appropriate transfer-function circuit and feeding the arbitrary time-varying boundary conditions as an input signal. The input may be specified as gas reservoir pressure, pore volume or the water flux. Several cases studied include an isolated gas reservoir on a limited aquifer, interference among three reservoirs adjacent to a common aquifer and the growth of gas-storage volume on an aquifer. It is concluded that the method developed on an electronic differential analyzer provides an excellent technique to simulate and investigate the behavior of gas reservoirs subject to water drive. The agreement between the reservoir performance as predicted from the simulation technique and as measured from actual field data is found to be better than the range usually encountered in predicting water-drive behavior. INTRODUCTION It is generally known that some gas-storage reservoirs are located on top of blanket sands of large extent, saturated with brine called aquifers. Because the volume of the body of water associated with aquifers is usually very large and water is compressible, the cyclic pressure variations encountered in normal storage service inevitably cause unsteady, compressible flow conditions in the adjacent aquifers. The solution to radial diffusivity equation for a limited aquifer for constant terminal conditions has been know111 since the early 1930's. The solution for the constant terminal conditions for an infinite aquifer was puhlished in 1949.2 The proldem of handling the unsteady flow of water through a porous medium with time-varying boundary conditions has been studied by many investigators through the use of graphical,3 digital4 computing techniques or on an R-C type of electrical analog called a reservoir analyzer.5 The digital computer performs a series of arithmetic calculations to superimpose the solutions of constant terminal conditions, while the R-C type of analyzer permits the simulation of the continuous medium by means of "lumped-cell" electrical resistance and capacitance elements based on finite-difference approximations. The graphical method is based on the convolution integral solution of the partial differential equalion. The purpose of the present study was to simulate the behavior of an aquifer on a general-purpose, electronic differential analyzer to obtain the influx of water or the change in pressure at the reservoir continuous1r and quickly. The use of the electronic differential analyzer was based on well known solutions for the constant terminal conditions already available in the literature.2,6-8 THEORETICAL DEVELOPMENT MODEL. The gas reservoir (R) is described in relation to an aquifer in Fig. 1. The permeability and porosity of an aquifer sand, the viscosity of the brine, and the compressibility of the brine and the formation are assumed to be constant. It further is assumed that the blanket sand is not thick enough to give appreciable vertical pressure distribution. The model in consideration is circular with radial geometry. The aquifer radius can be of limited or infinite extent. The gas-water interface is assumed to be fully segregated, and the displacement of the gas by

By Raymond C. Johnson

GASIFICATION is important to the anthracite industry, as it is to the entire solid-fuel industry and to the nation. However, to the anthracite industry it may have particular significance in that it would increase the market value of many millions of tons of a by-product fuel, which the industry now has in storage and is currently producing, in addition to increasing the potential market for all its products. The by-product fuel is of usable quality but the ash content is higher than it can be in other products and therefore it must be converted or used at the point of production. Gasification is one method by which the product may be given increased value. The inherent characteristics of anthracite make it well suited for producing a fuel or synthesis gas. It is the most concentrated form of natural commercial carbon, noncaking and noncoking; it does not produce smoke, tar, or soot and has a low sulphur content; and the volatile matter, which ranges between 2 and 8 pct, is 80 to 85 pct hydrogen with small amounts of methane, carbon dioxide, carbon monoxide, and nitrogen. The ash fuses at high temperatures, which allows it to be burned at high rates without slagging. However, with the addition of small amounts of dolomite, the ash will form a slag, or glass, which is very fluid. Anthracite has long been used in the manufacture of city gas and it is extensively used in various parts of the country to make water gas to be converted to hydrogen. Buckwheat and rice anthracite are used in Galusha producers to make producer gas. Excellent synthesis gas has been made in a Galusha producer with rice and barley anthracite with oxygen in tests at the Consolidated Mining and Smelting Co., Trail, British Columbia. In these tests, anthracite was shown to have advantages over competitive fuels, in that the gas had a higher hydrogen content and could be cleaned with less difficulty. The anthracite seams are steeply pitching and in mining the parting strata and some of the roof and bottom materials are taken with the coal. In preparation, these materials are separated by gravity from the commercial product and stored in refuse banks. This refuse contains a mixture of rock, slate, or shale, and high-ash anthracite with bone coal, which is low-ash coal that is interspersed with thin bands of shale. The bone coal contains between 25 and 50 pct ash with an average ash content of approximately 30 pct, with a

Jan 1, 1953

By Reed W. Hyde

SOME information has been published on the sulphur dioxide concentration of gases from Dwight-Lloyd machines sintering lead ores but most of this relates to the customary practice in which the charge is relatively high in lead and is sintered in two passes over the machine. It is thought, therefore, that the following observations on sintering in one pass a low-lead, low-sulphur charge may be of interest. The data were obtained in sintering lead sulphide flotation concentrates mixed with minus 20-mesh oxide ore, the mixture carrying 16.8 per cent Pb and 5.3 per cent S. No returns were used because of the limited amount of sulphur available as fuel, but the mixture pelletized readily to make a satisfactorily permeable bed on the sintering machine. As there was a possibility that the SO2 might be utilized, a series of runs was made to determine the concentration of SO2 in the gases at different points along the wind box, and the effect on this concentration of changes in the wind-box vacuum. Several runs each were made with vacuums (as measured in inches of water at the wind box) of (1) 2 to 1 3/4 in., (2) 4 to 3 1/2 in. and (3) 6 to 5 1/8 in. The averages of the determinations from each series are platted on the graph (Fig. I). The vertical scale shows the percentage by volume of SO2 (as determined by the Reich method), and the horizontal scale shows the time expressed as percentage of the total sintering time. Sintering was considered to be complete when no SO2 could be detected in the gases. In all cases the depth of bed was 4 1/2 in. and the weight of dry charge per square foot of hearth area was 45.2 lb. Other data are given in the table. The volume of gases corresponding to the several points along the wind box at which SO2 determinations were made could not be measured, but has been calculated from the SO2 content and sulphur elimination on the assumption that the volume is uniform throughout the sintering period. This is not strictly true, as with a given vacuum the volume will usually drop slightly toward the middle of the period and increase toward the end. However, this assumption is a reasonable approximation. Several interesting features are brought out by these data. In general, the published data on SO2 concentration in sintering under ordinary conditions show a high SO2 concentration in the early stages followed by a rapid decrease in concentration and with relatively little SO2 in the gases from the last half or third of the operation. In other words, the greater part of the sulphur elimination is obtained in the first third or half of the period. In these runs, the 6-in. vacuum, which approximates the usual operating condition, gives a curve that follows this customary pattern. Maximum SO2 concentration is obtained 2 ½ min. after

Jan 1, 1942

By William N. Matheson

The major consideration in any management and engineering decision is the economic evaluation of factors. The right decision is the best cost decision, provided of course that it is the safest. Changes, improvements, and advances in mining technology, as in any business, come about through the pressure of economics in combination with the inventiveness and engineering abilities of efficient mine operators. Without proper economic evaluation and an appreciation of profit and loss of an operation, advances in mining methods would come about at a slow pace, if at all.

Jan 4, 1959