Search Documents

By Glenn B. Southward

The V system of mining used at the Norton mine of West Virginia Coal & Coke Co. was designed as a modified long wall with face conveyors, for use under roof conditions that would not permit regular long-wall methods. This mine is in the Lower Kittanning seam, which averages about 6 ft. in height. There is from 20 to 30 ft. of slate and shale immediately over the coal and above this is a bed of sandstone 40 ft. or more thick; the total cover will vary from 50 to 250 ft. In the room-and-pillar workings, the top in the rooms and headings is generally good but it is

Jan 1, 1924

By A. F. Baker, E. R. Palowitch, A. W. Deurbrouck

As air-pollution regulations become increasingly more stringent, increased significance is being placed on the amount of sulfur present in coals used for steam generation. These regulations are aimed at minimizing the pollution of the atmosphere with noxious gases such as the sulfur oxides that are formed and emitted when coal is burned. Two meet these future requirements, a definite need exists to reduce the sulfur content of some of the coals used for steam generation. Reducing pyritic sulfur involves liberating the pyrite from the coal and then removing it. The specific gravity of pyrite is high (5.0) compared to that of coal (about 1.2, mineral-free), and standard coal-washing devices, such as wet concentrating tables, will efficiently remove pyrite particles larger than about 100 mesh. Particles below this size will be entrained in the table water and will be carried into the clean coal product. Techniques such as froth flotation are of little benefit for pyrite reduction because the flotation characteristics of pyrite are similar to those of coal.

Jan 6, 1966

By John J. McKetta. Jr., Louis B. Lesem, George H. Fancher

The proration of oil produced in the field frequently is based partially or entirely upon the gas-oil ratio of wells. The measurement of the gas-oil ratio is one of the more important field tests in regulatory and pro-ration work, and the test always should be conducted according to standardized methods and procedure. Obviously, the gas-oil ratio and the volume of gas produced by a well depend upon many factors but should be independent of the method of measurement and of the devices used to measure gas and oil. Consequently, the volume of gas accompanying a barrel of oil produced by a well may be measured by any reliable and accurate device or instrument. Frequently either a critical flow prover or an orifice well tester is used for this purpose, and for a particular well the same rate of flow of gas should be obtained regardless of whether a critical flow prover or an orifice well tester is employed in the test. In Texas, when using either instrument, either Capacity Table 1 or 5' is employed in making the necessary computations. If the tables are used, a discrepancy always is found whenever the two instruments are compared by extrapolation to the same conditions of flow. Clearly, Tables 1 and 5 must be at fault in some respects. The orifice well tester and the Bureau of Mines type of critical flow prover are essentially the same instrument; both devices utilize a square-edged orifice 1/8 in. in di-ameter as the primary element, and both freely discharge gas to the atmosphere. Tables for the orifice well tester' have been published in the ranges of 0 to 15 in, of water and 0 to 40 in. of mercury (Hg) differential in pressure. Coefficients for the critical flow prover have been published for differentials in pressure greater than 75 psia. An extrapolation of either differs from the other set of data as much as 18 per cent at some points. No immediately obvious reasons for the discrepancy was found, and data available from the literature were insufficient to effect reconciliation. Consequently, a series of experiments was performed to check the available data and to determine discharge coefficients for the two devices in an overlapping range of differential pressure. The correlating equation used in preparation of tables such as Tables 1 and 5' is the so-called hydraulic equation, Q = C1 vh .....(1) The tables cover orifice sizes from 1/8 through 1 1/4 in. A second set of tables, for use with greater differentials in pressure, apply only to the 3/4, 1, and 1 1/4-in. orifice plates over a pressure range of 0 to 40 in. of Hg. The correlating equation used in preparation of the tables is Q = C2 vH(29.32 + 0.3H)/G . (2) Each of these equations is valid only for the range to which it has been applied, and neither equation is valid for extrapolation. Theoretical equations for flow through an orifice are based upon assumptions of fractionless flow and an emergent jet the size of the orifice. A multiplier, C,, called the discharge coefficient, is inserted into the theoretical expression to compensate for both frictional losses and the contraction of the jet experienced in the plane of the orifice. Buckingham3 shows that C, should vary with the ratio of upstream to downstream pressure for flow of a compressible fluid at any average linear velocity through the orifice less than the velocity of sound. Work published by the National Advisory Committee for Aeronautics4 indicates that the variation continues into the so-called critical flow region until the vena contracta coincides with the plane of the orifice. The NACA work, however, does not indicate a leveling off of the coefficient. The work of the Bureau of Mines5 for the critical flow prover was based on differential pressures greater than 75 psi and indicates that the discharge coefficient, Cd, is constant in this region at a value of about 0.86.

Jan 1, 1958

By Carle R. Hayward

THOUGH recent months have seen a rapid decline in lead-smelting activity and consequent uncertainty as to the future, the first half of the year showed progress in keeping with similar activity in other metals. Demand for scrap increased and various lead-bearing materials found their way to plants producing secondary lead. Some of these materials introduced complications into normal smelting procedure and were the cause of many conferences among plant officials attempting to find the most satisfactory method of treatment. If a blast furnace is to do itself justice it must be run with an open charge. Troubles inevitably result when materials are added to a charge which tighten it up and pre- vent free burning of the coke and con- sequent rapid smelting with a clean hearth This fact has long been recognized by plants producing primary lead, but only recently only it received the attention it deserves.

Jan 1, 1938

By N. J. Grant, B. C. Giessen, M. Morris

The slvuclures of alloys in the system In-Bi have been investigated after (levy vapid queuching from the mell (splat cooling) to -190°C. Tuo-phase fields could be suppressed over most of the tota1 concentvalion range; five melastable phases a1, a2, ?, ?1. and ß exisl, of which four have simple elementtike structures. For example, ß has the A5 struclure of white till. Crystal-tographic data and coordination numbers for these phases aye given, as well as addilional information on the equilibrium diagram, where a new phase In5Bi3 teas found. THE phase diagrams of binary combinations of B elements from the groups B2, B3, B4, and B5 are usually of a simple type and show considerably fewer intermediate phases than combinations of these elements with A metals, transition metals, or the B1 noble metals. Aside from phases such as the typical B3-B5 compounds with the ZnS-B3 structure type, few stoichiometric phases are known; among them are In2Bi and 1nBi.l Nonstoichiometric phases include ß (In-Sn), a1, (In-Pb), and the tin-rich ? phases in the In-Sn, Cd-Sn, and Hg-Sn systems.' The first two phases have a close relationship to indium, while the latter group are known to be structurally related to a Sn. Thus, there are generally no immediate experimental data for the correlation of the crystal structures of B metals and B metal combinations with certain monotonously varying parameters, such as the valence electron concentration (VEC), or the average atomic size. Such parameters have been recognized as structure determining, e.g., for the transition 4 Sn — y phase,2,3 where nonintegral valence electron concentrations are encountered. It should be possible to extend such correlations to other binary systems, if nonequilibrium single-phase alloys could be produced over broad valence electron concentration ranges, and if their crystal structures could be regarded as being imposed by their electronic states. It has been shown in the case of the tin-rich 7 phases3 that alloy phases with typical crystal structures can be produced in B metal alloys rapidly quenched from the liquid to -190°C by the splat cooling technique due to Duwez,3-8 and reviewed in Refs. 5 and 6. The In-Bi system was selected because it extends over a valence electron concentration range in which several metastable, nonstoichiometrir phases could be expected to occur. Further, the low melting points of the known intermediate phases, In2Bi and InBi, Fig. 1(a), indicated low binding energies and thus possibly low driving forces for the formation Of the equilibrium structures. EXPERIMENTAL TECHNIQUES AND RESULTS The preparation of the quenched foils followed the practice described in Ref. 3. Master alloys were produced by melting of indium (99.97+) and bismuth (99.99+) in evacuated Vycor capsules or in an inert gas arc furnace; quantities of 20 mg were splat-cooled onto copper and silver substrates held at - 190°C; and crystal structures and lattice parameters were determined on a GE XRD-5 diffractometer using Cu Ka, radiation at -190°C and at room temperature. The duplication of each run with both substrates permitted the elimination of overlap of the substrate diffraction pattern and that of the investigated substance. The XRD patterns were usually taken from sin2 " = 0.03 to 0.35; the substrate was used as a means of internal calibration. The fractional accuracy of the lattice parameters of metastable phases is approximately 10-3 In the following, all percentages are in atomic percent. The stable and metastable phases found after rapid quenching to -190°C are listed in Table I, together with estimated concentration ranges and crystallographic data. The investigated alloys and phases present in them are given in Table 11. Except for the region between indium with 33 and 50 pct Bi, where a revision of the equilibrium phase diagram became necessary to include a new stoichiometric phase In5Bi3, the diffraction patterns taken after heating to room temperature agreed with those expected from the phase diagram, Fig. l(a). This suggests that the new nonstoichiometric phases are not stable at room temperature, thus following the observations made for the y phases based on tin.3 Results concerning the equilibrium phases In2Bi and In5Bi3 and the revision of the equilibrium phase diagram which is made necessary by the inclusion of In5Bi3 will be treated first. The Crystal Structure of In2Bi. Makarov7 had identified In2Bi as belonging to the AlB2-C32 type ; however, in a later paper the structure was revised.8 In2Bio was found to be of the Ni21n-B8ß type,21 with a = 5.496A, c = 6.57.9A, and N = 6 atoms per unit cell.9 This crystal structure was confirmed in the present work; definite evidence for the doubling of the c axis, as compared to the A1B2-C32 type, and for the proposed order structure, was found in the powder pattern. The observed lattice parameters agree well with those of Ref. 8; those measured at -190°C are given- in Table I. The Crystal Structure of In5Bi3. A new, equilibrium, intermediate phase was identified in slow-cooled, as-cast alloys; it was identified as In5Bi3. The structure has been worked out by Giessen and Grant;" lattice parameters at -190°C are given in Table I. This phase is probably identical with "In3Bi2", produced by vapor deposition techniques, but not recognized as an equilibrium phase by Palatnik et a1.11 After completion of the present work, the existence of In5Bi3 has also been demonstrated by superconductivity measurements on In-Bi alloys.20

Jan 1, 1968

By S. M. Wu, R. L. Stone, T. D. Tiemann

The dissolution of silica from quartz in sodium hydroxide solutions was investigated by statistical methods. A second-order predicting equation was developed with 28 experiments expressing the dissolution of silica as a function of the variables quartz size, time, temperature and sodium hydroxide concentration. With this equation a comprehensive picture of the dissolution reaction was gained which included the effect on extraction of each variable and their interactions, fractional extractions, reaction rates and activation energies. A previous investigation of the extraction of silica from low grade siliceous iron ore by digestion in sodium hydroxide solutions presented the extraction as a function of time, temperature and sodium hydroxide concentration.' The present paper is an outgrowth of the previous work and develops by a mathematical analysis the functional relationship between the extraction of silica and time, temperature, sodium hydroxide concentration and particle size. Relatively pure quartz was used in this study in order that the basic quartz-sodium hydroxide reaction could be studied without the influence of other constituents that are commonly found in iron ores. The functional relationship between the dissolution

Jan 1, 1965

By R. W. Gurry

IN the course of a series of measurements of the rate of diffusion of carbon in austenite at about 960°C. (1760°F.) and 1110°C. (2030°F.), it became necessary to determine carbon concentration when austenite is saturated with graphite, because of indications that the hitherto accepted value of the solubility of graphite in this temperature range is too low. Specimens of carbonyl iron were saturated at temperature in a hydrogen-toluene atmosphere which was in equilibrium with graphite. The carbon content of the steel was measured either by combustion or by the loss of weight after substantially complete decarburization in an atmosphere of hydrogen saturated at room temperature with water vapor. The absence of carbide or graphite as a phase at temperature was demonstrated by microscopic examination of saturated specimens that had been drastically quenched. The mean result of concordant measurements is that gamma iron saturated with respect to graphite contains 1.39 per cent carbon at 957°C. (1755°F.) and 1.89 per cent at 1110°C. (2030°F.). These two values, plotted along with what appears from the literature to be the best value (0.69 per cent) at the iron-graphite eutectoid temperature (738°C. or 1360°F.), yield a curve that is almost linear, and which, continued upward through a short interval, leads to a limiting solubility of 1.98 per cent at the iron-graphite eutectic temperature 1135°C. (2075°F.) instead of the commonly accepted value of about 1.7 per cent. EXPERIMENTAL PROCEDURE The samples of carbonyl iron, with the exception of those for microscopic examination, were cylinders 3.8 cm. long, 0.475 cm. in diameter. They were placed in a graphite holder and suspended in a vertical furnace, the temperature of which was controlled precisely by means of the resistance of the platinum winding.1 In the empty furnace the range of temperature over a distance of 4 cm. at the heat center was 9°C. (16°F.) but at a given location the temperature remained within ±0.5°C. (0.9°F.); it was measured by inserting a platinum-rhodium couple calibrated at the melting point of palladium, 1555°C. Since the presence of the sample probably improved the uniformity of temperature, it was decided to consider the average temperature of the sample to be 3°C. lower than the maximum measured in the empty furnace with the same setting of the controller. Data were obtained in the vicinity of two temperatures, 960°C. (1760°F.) and 1110°C. (2030°F.). The samples for microscopic examination, 2.2 cm. long, 0.475 cm. in diameter, were suspended individually on pure iron wire; for these no temperature correction was applied. The carburizing gas passed into the furnace was dry, oxygen-free hydrogen saturated at room temperature with

Jan 1, 1942

By W. J. Skewes, C. T. Holland

Properly constructed stopes are necessary underground for proper ventilation and safe, healthful working conditions. Mining companies are concerned with providing the best possible stoppings at an economic cost. It is important to consider 1) proper materials, 2) construction that ensures maximum performance from the material used, and 3) keeping costs within reasonable limits for the unit operation—stopping—involved. The authors investigated all aspects of the problem and have attempted to layout a study program to provide information on all phases. Mining companies every year purchase huge amounts of material for the construction of ventilation stoppings. This material by the time it is in place in the stoppings will cost the company many thousands of dollars. In addition and more importantly these stoppings are supposed to confine air travel along certain well defined paths into areas where it is needed to provide safe and healthful atmospheres for workmen. The cost of forcing this air through the mine is large and in general increases as the total quantity increases. Consequently, if the stoppings leak, increased cost results and in addition unsatisfactory ventilation may prevail in the mine. Therefore, it is essentia1 to provide the best possible stoppings at an economic cost. When attempting to provide the best stoppings possible at an economic cost, three aspects of the problem must be considered. These are 1) getting the most suitable material for stopping constructions, 2) constructing the stopping so as to get the best performance from the material used, and 3) keeping the cost of stopping construction to a minimum for a suitable stopping. This investigation is concerned with all phases of the problem and has attempted to lay out a study to provide information on all of them. In order to develop information on the best stopping material available it seemed wise, after con- sidering the job a stopping must do, to investigate the following aspects of material used for stoppings: 1) strength in compression, 2) compressibility or yield under load, 3) porosity, and 4) permeability. To provide information on the best manner of construction the following aspects of air leakage through the stopping were investigated: 1) when the stopping is built of dry stacked materials—i.e., the joints are not mortar-laid (See Fig. 1); 2) when the stopping is built of dry stacked material and then plastered on one side (see Fig. 2); 3) when the

Jan 1, 1961

By G. H. Bishop

The kinetics of the inter granular penetration and embrittlement of [100] tilt boundaries in 99.998 pct pure nickel upon exposure to bismuth-rich Ni-Bi liquids have been determined in the temperature range from 700° to 900°C. The kinetics of penetration are parabolic in time at constant temperature over most of the temperature range. In a series of 43-deg bicrystals the rate of penetration is anisotropic with respect to the direction of penetration into the grain boundaries. In lower-angle bicrystals the penetration rate is isotropic. The rate of penetration decreases with tilt angle at 700°C. The activation energy for penetration in the 43-deg bicrystals is 42 kcal per g-atom independent of direction. It is concluded that the intergranular penetration and embrittlement in the presence of the liquid proceeds by a grain boundary diffusion process and not by the intrusion of a liquid film. This was confirmed by a determination that the kinetics of penetration and embrittlement were the same in the 43-deg bicrystals upon exposure to bismuth vapor under conditions such that no bulk liquid phase would be thermodynamically stable. WhEN solid metals are exposed to a corrosive liquid-metal environment, the grain boundaries are sites of preferential attack. Depending on the temperature, the composition of the liquid, and the composition, structure, and state of stress of the solid, a number of modes of attack are possible. This paper reports a study of the kinetics of intergranular penetration and embrittlement of high-purity nickel bicrystals upon exposure to bismuth which, together with an earlier study by Cheney, Hochgraf, and Spencer,&apos; demonstrates that there are at least two modes of intergranular attack possible in the Ni-Bi system. In the study by Cheney et al., columnar-grain specimens of 99.5 pct pure nickel were exposed to liquid bismuth presaturated with nickel in the temperature range 670" to 1050°C. They found that the majority of the boundaries, which were predominantely high-angle boundaries, were penetrated by capillary liquid films, the attack proceeding by a process which will be termed grain boundary wetting. This process occurs in a stress-free solid when twice the liquid-solid surface tension is less than the surface tension of the grain boundary,* i.e., when 2yLs < YGB In this case the penetration of the grain boundary by the liquid occurs at a relatively rapid rate, resulting in the severe embrittlement of a polycrystalline solid. Grain boundary wetting is a common mode of intergranular attack in systems in which the lower melting component is relatively insoluble in the solid, but the solid has an appreciable solubility in the liquid, for example, the Ni-Bi system, Fig. 1. In systems of this type at temperatures above the range of stability of any intermetallic phases, once the liquid is saturated with respect to the solid so that no gross solution occurs, chemical gradients are small, and surface tensions become major driving forces for attack, provided the solid is stress-free. The results of Cheney et al. appear to be typical of those encountered when grain boundary wetting occurs.&apos; Capillary films were observed in the boundaries after quenching from the exposure temperature. The mean depth of penetration increased linearly with time, and the activation energy for the process was found to be 22 kcal per g-atom. In a study of the Cu-Bi system Yukawa and sinott4 found that the depth of penetration of bismuth into high-purity copper bicrystals of orientations from 22 to 63 deg of tilt about (100) at 649°C ranged from 0.05 to 0.25 in. after a 12-hr anneal. This corresponds to a linear rate of 6 to 15 X 10~6 cm per sec. At the same reduced temperature of 0.68 the rate for the Ni-Bi system&apos; was 7 x lo-&apos; cm per sec. In another study of the Cu-Bi system, Scheil and schess15 determined the kinetics of grain boundary wetting in hot-worked commercial rod. While there were several complicating factors present in this study, there is general agreement with the above results. The kinetics of penetration were linear, the activation energy was 20 kcal per g-atom, and at 650°C the rate of wetting was 2 to 5 x 10-6 cm per sec. The rate of wetting in the A1-Ga system6 is somewhat

Jan 1, 1969

By Marie L. V. Gayler

WITHOUT diffusion taking place in liquid metals and alloys, no castings could be made; it is therefore the most important factor affecting the structure of metals. Diffusion involves the interchange of atoms, a process which takes place during the life history of an ingot. In the liquid, atoms are in a state of high thermal agitation, but this thermal vibration is reduced in amplitude with falling temperature. When solidification sets in, the atoms arrange themselves on an ordered space lattice and the changes in structure which take place in the solid are due to the interchange of atoms on this space lattice. The rate of atomic interchange-e.g., of diffusion-is most rapid at temperatures close to the melting point and decelerates as the temperature is lowered. At room temperature, the rate of diffusion is practically negligible in most alloys, and any change in structure can only be brought about by using methods which will accelerate the rate of diffusion. The rate of diffusion depends on three factors (I) temperature; (2) concentration gradient and (3) activation energy. The growth of grains and particles in the solid alloy also depend on these factors and are therefore intimately associated with diffusion. The rate of homogenization in a cast alloy depends on several factors, such as: (I) rate of solidification, which involves grain and particle size which, in their turn, depend on diffusion: (2) the nature of the constituents; (3) the temperature interval between the melting point of the metal or alloy and the temperature at which it is being heat-treated. It is well known that coarse, cast structures are extremely difficult-if possible to homogenize, and the finer the grain size and particle size, the more readily solid solution will take place. The rate of diffusion depends, also, largely on the nature of the constituents; for instance, copper and magnesium form solid solutions with aluminum quite readily but nickel and iron do not; neither do certain intermetallic compounds, such as alpha and beta FeSi. Furthermore, the actual formation of intermetallic compounds may be a very slow process, particularly when they are formed in the solid state as equilibrium products. For example, ßFeSi is formed in the solid as the result of the reaction aFeSi + Al?ß FeSi. The particles of aFeSi become sur¬rounded with a reaction ring of ßßFeSi. This layer is formed as the result of diffusion of atoms taking place between the aluminum matrix and aFeSi. As the amount of ßFeSi surrounding the core of aFeSi increases the concentration gradient becomes low and so the rate of diffusion of atoms also decreases until it practically ceases. This occurs after a comparatively thin layer of ßFeSi has been formed. It follows that when intermetallic compounds of this type are formed in the solid, as the result of diffusion, it is generally impossible ever to attain equilibrium, since the forma-

Jan 1, 1944

THE slag performs two useful functions in open-hearth steel- making. First, it is the means of disposal of all the impurities, save carbon, which are removed from the charge materials in refining the steel, so it must be suited to receiving and retaining as much as possible of undesirable elements with minimum loss of iron and useful alloying elements. Second, the slag serves as a buffer between the flame and the bath and transfers oxygen to the metal at a measured pace contrasted with the violent and difficultly controlled oxidation of the bessemer process. At the same time, the slag is a thermal insulator that limits the rate at which heat can be delivered to the metal from the flame, and a heavy slag blanket thereby serves as a brake on production rates. It has been said with justification that the secret of good steel- making is to make a good slag and the steel will take care of itself. In a broad sense, the subject of slag control includes not only the adjustment of the composition of the slag but also of its relative weight in terms of percentage of the metal-bath weight. The slag is made up essentially of: (1) oxides formed by oxidation of silicon, manganese, phosphorus, and iron in the charge, (2) Si02, MnO, MgO, and other oxides charged as such or introduced incidentally with ores or fluxes or by refractory erosion, and (3) lime charged or fed to the heat to neutralize the "acidic" oxides present (Si02 and P205). Obviously, if practically perfect control were possible over the composition of the charge as well as over the oxidation process during the melting period, both slag weight and composition would be very nearly predetermined; and the control problem would be solved. Unfortunately, only a somewhat imperfect control over these factors is possible, so the operator must begin during the lime boil and continue through the refining period to discover and correct departures from the normal pattern of slag development. To do this as the heat progresses, the first helper must be able to make quick estimates of the composition and physical state of develop-

Jan 1, 1964

By V. GUDKOV

THE iron-ore deposits of Russia were estimated at 2,200,000,000 by the Russian Geological Survey, in 1910; but this estimate must be considered as being far too low. The estimate for Siberia, which had been explored very little for iron ore, was placed at about 27,000,000 tons. The exploration, in 1912-14, of the three iron deposits-Blagodat, Baakal and Kamensk-raised the estimate of the iron-ore reserves or the Urals from 282,000,000 tons to about 400,000,000 tons. Conservative estimates of the explored deposits made by the writer in 1915, gave the following figures: Southern Russia 900,000,000 tons, Ural Mountains 500,000,000 tons, Central Russia 900,000,- 000 tons, Siberia 100,000,000 tons, Caucasus 20,000,000 tons, or a total of 2,420,000,000 tons of iron ore, or 1,200,000,000 tons of pig iron.

Jan 1, 1921

By S. H. Chauvenet

HARRISBURG is situated on the Pennsylvania Railroad, one hundred and five miles from Philadelphia, two hundred and forty-eight miles from Pittsburgh, and ninety miles from Baltimore, and has running through it the Pennsylvania, Northern Central, Philadelphia and Reading, and Cumberland Valley Railroads, and the Pennsylvania Canal. Surrounded by a thickly settled farming country, from which to draw native labor, within easy distance of anthracite and bituminous coal, with ores and limestone near at hand, and with the Susquehanna River as a never-failing water supply, Harrisburg has advantages for manufacturing which warrant the investment of the capital that has already been made, and has a future as a manufacturing city second only to Pittsburgh and Philadelphia. THE PENNSYLVANIA STEEL COMPANY, L. S. BENT, SUPERINTENDENT. The works of this company, the largest in Harrisburg, lie between the Pennsylvania and the Philadelphia and Reading Railroads, on. the Pennsylvania Canal, and are essentially devoted to the manufacture of Bessemer steel rails. Capital stock, $2,000,000; invested in business, $5,000,000; wages per month, $80,000; employs 2000 men; capacity, 100,000 tons of rails per year, which is being increased to 130,000 tons. The plant, as it now stands, comprises five Bessemer converters, two 7-ton and three 8-ton converters, two 15-ton open-hearth furnaces in operation, and two 30-ton open-hearth furnaces in course of construction, one blooming mill, one rail mill, seven steam hammers, two blast furnaces in operation, two blast furnaces in course of construction, foundry, pattern $hop, machine shop, blacksmith shop, and frog shop, and merchant mill in course of construction. Bessemer No. 1 was built in 1865, with two 7-ton converters, 2 spiegel cupolas, 3 feet diameter, and 3 iron cupolas 6&apos; 6" diameter,

Jan 1, 1882

By C. R. Johnson, R. A. Greenkorn, G. W. Widner

This paper describes a short, simple well-testing procedure evolved from unsteady-state concepts to appraise wellbore damage in water-input wells. Input rates are changed at specific intervals over a 30-minute period and the wellhead pressure recorded at the end of each interval. From these data, the pressure drop due to the "skin" can be computed. This pressure drop in terms of psi/B/D of input rate is referred to as the "skin factor". Two of these variable-rate tests are required to determine change of wellbore damage and to evaluate well-treatment techniques. There are several advantages to the variable-rate procedure. The necessary data can be obtained with wellhead gauges and meters. There is little interference with normal operations. The short testing period eliminates many interpretative difficulties that come from interference from adjacent wells. The shut-in period required for standard tests before the plot of pressure vs log of time attains a straight line is often 12 hours or more. Such a time period is incronvenient, especially when a well must be tested repeatedly to evaluate change in wellbore characteristics. This variable-rate procedure has been successfully npplied to water-input wells in three fields. For some of the wells, skin factors were calculated from both the standard and the variable-rate tests. These results show good agreement. THEORY OF THE VARIABLE-RATE PROCEDURE In many waterflood input wells, the pressure in the wellbore differs from the pressure in the reservoir immediately adjacent to the well because of the restriction of flow through the skin of the well. If the true pressure of the reservoir at the well, p,, is that pressure which would exist in the well if no skin were present, and p,&apos; is the actual pressure as measured in the well, this difference, is the skin effect. Fig. 1 shows the change in skin effect with change in flow rate. As the flow is reduced, the skin effect is reduced by an amount equal to the change in wellbore pressure minus the change in reservoir pressure. The equation of pressure change without skin using the point-source solution of the diffusivity equation is (after van Everdingen&apos;)

By Arnulf Muan, Hobart M. Kraner

Ferromanganese alloys react with aluminu-silica brick in blast furnace hearths and cause the formation of new phases with low refractoriness and consequent failure of the refractory lining. The nature of these reactions is explained on the basis of petrographic observations, thermodynamic data, and Phase equilibrium considerations. Animproued hearth design resulted from these findings. The production of ferromanganese in blast furnaces presents many problems which are not encountered in the production of iron in the same furnaces. One of the most serious of these problems is the rapid failure of refractories caused by their reaction with the ferromanganese metal. The present paper describes such a "hearth attack", its symptoms, causes, and cure. Following an introductory discussion of operating practice in ferromanganese blast furnaces, results are presented of a petrographic examination of samples from a furnace which had to be shut down because of refractory failure. The causes of this failure are then analyzed on the basis of petrographic observations combined with thermodynamic and phase equilibrium data available in the literature. The latter type of data were subsequently used as a guide in recommending improvements in hearth designs which have since proven themselves successful in practical operations. I) FERROMANGANESE BLAST FURNACE PRACTICE It is considered good practice to blow in a furnace on iron and operate it in this way for a period of time preliminary to producing ferrornanganese. During this time, iron generally penetrates the bottom refractories six or more feet below the original working surface of the hearth. Not only does this metal pervade the joints to these depths, but the pores of the refractories are usually also filled by molten iron. The high throughput of the iron furnace provides ample heat to maintain a high temperature in the hearth refractories. This, together with a high ferrostatic pressure, causes porous clay brick of the hearth to shrink. During subsequent use of such a furnace in ferromanganese production, the iron in the pores of hearth brick if; replaced to some extent by ferromanganese. The replacement is usually not complete. This is probably due to the lower metal throughput and lower prevailing temperatures resulting from this in the brick of the hearth bottom. When the ferrornanganese furnace is banked—or when the temperature in the furnace falls due to a furnace delay—-manganese oxidizes even though the atmosphere is largely CO. Considerable expansion accompanies this oxidation of manganese from metal to oxide. The hearth refractories are then subjected to the disintegrating forces of the volume expansion. These forces may in extreme cases be large enough to lift the furnace off its mantle supports as was described in a previous paper.&apos; When cooling takes place slowly, however, and the temperature remains at a fairly high level, the refractories undergo fluxing action by the MnO. This latter reaction and the reduction of SiO2 of the clay brick is the general subject of the present paper. The observations to be described herein were made on a ferromanganese furnace located at the Johnstown plant of Bethlehem Steel Co. The furnace was lined entirely with clay refractories and had operated on iron for 266 days and on ferromanganese for 96 days prior to being taken off because of a hearth wall failure. II) PETROGRAPHIC EXAMINATION AND CHEMICAL ANALYSIS The photograph reproduced in Fig. 1 shws a cross section of the upper part of an 18 by 9 by 4-1/2 in. bottom block removed from the blast furnace. This brick came from a depth of approximately 6 ft below the original working face of the bottom. It will be noted that the 4-1/2 in. dimension is almost the same as when the brick entered the furnace. Three characteristically different zones marked I, II, and III on the print of Fig. 1 are apparent. Results of chemical analyses of the original brick and samples from each of these zones are listed in Table I. Petrographically the various zones were characterized as follows: The central zone marked I was essentially un-reacted brick. The microstructure consisted of fine needles of mullite, and the pores in this entire area were filled with iron. This is characteristic of

Jan 1, 1962

By J. L. SCHUELER

THE writer has reread Mr. Ingalls&apos; interesting article in the July, 1923, issue of MINING AND METAL- LURGY on "The Use of Spelter in Galvanizing." It seems that most writers, in commenting upon coatings of spelter on sheets and wire, dwell upon the thin coatings which these materials carry, and rightly so. However, they seem to forget that until very recently, in the case of wire, the manufacturer did not know how to apply a heavy coating of spelter to the wire, especially if the wire was to be woven into fence or fabricated in some other manner, because heavy coatings of spelter are exceedingly brittle. This is even true in the case of high-grade spelter, but to a lesser degree than with Prime Western. Because of this brittleness, it has been necessary for wire manufacturers to smooth the coating by passing the wire through tightly compressed wiping means of some kind, usually asbestos. This removes all of the excess spelter and allows only a thin coating to remain. The latter, as a rule, is malleable and the wire can be fabricated without material injury to the coating.

Jan 1, 1924

By GILBERT E. SEIL

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

Jan 1, 1944

By Sheldon P. Wimpfen, Ralph H. Sweefser

FOR centuries the pumping of water has been one of the chief problems to be overcome by the persistent men who win the mineral wealth of the world. Profitable operations have often been forced to suspend activities as the mine penetrated well below the water table or when sudden rushes of water were encountered. To operate below the local water level requires continuous pumping equal in volume to the amount of water flow¬ing into the mine workings. Often the water to be removed exceeds the tonnage of valuable material produced. To be above local water level is a valuable asset. Modern mining practice permits nothing short of the extraction of the last pound of profitable ore from a mineral deposit. In the days before the development of mechanical and electrical power as we know it today. water in any quantity was a major

Jan 1, 1948

By J. B. Austin

Jan 1, 1945

By Norman Ketzlach

Manganese Products, Inc. has developed a chemical process for the recovery of high-grade manganese oxides from low-grade manganese ores. Ammonium sulphate is also produced. Manganese ore is leached with sulphurous-sulphuric acids. The impurities are removed with ammonia, heat, and air. Manganese oxides are produced by addition of more ammonia and air under pressure. Ammonium sulphate is recovered from the remaining solution.

Jan 3, 1950