Search Documents

By S. R. B. Cooke, R. O. Huch, C. S. Chang

IN the flotation of iron ores laurylamine derivatives have been used for considerable time.12 To effect satisfactory separation of the gangue, predominantly silica, from the iron oxide minerals, the addition of specific depressants for the iron oxides has been found necessary. Starches and starch products have been used for this purpose. 3 There is, however, very little published information on the effects of these materials and other variables on this process. In some cases it has been found that prior acid scrubbing and desliming are essential, 4 and depending upon the efficiency of the subsequent washing step, there will be accompanying changes in pH. It was the object of this investigation to test and observe the effects of the above factor as well as to examine and compare the action of various starches and starch products.

Jan 12, 1953

By N. A. Gokcen, R. A. Dodd

Solubility of nitrogen in liquid iron-manganese system at 1550°C and one atmosphere pressure has been determined by a simple method. Results show that the solubility increases from 0.040 pct for pure iron to 1.41 pct for pure manganese. DETERMINATION of the solubility of gases in volatile metals. and alloys by the well-known Sievertsl method is unreliable. This is particularly true for the Fe-Mn system since Mn vaporizes readily from the alloys containing as little as 2 pct Mn, and, upon condensing on the cooler parts of the apparatus, it absorbs large amounts of nitrogen. Further, the condensing Mn vapor interferes with the usual method of temperature measurements with an optical pyrometer.

Jan 1, 1962

By Samuel Lasky

FAULTING at Kennecott, with its attendant fracturing, is unusual, complex, and important. As study. and knowledge of the various fault systems have progressed, appreciation of that importance has helped in the selection of proper horizons for exploration and in the avoidance of useless crosscutting and drifting. During the study of this faulting and fracturing, a suggestion concerning the formation of the ore-bearing fissures occurred to me. Further study in the available portions of the approximately 45 miles of workings in the Kennecott mines for the purpose of checking up the the suggestion led to the hypothesis which this paper will attempt to present. Briefly, the hypothesis may be stated as follows: The formation of transverse faults that stop against a main, system is connected with changes in the strike or dip of the main fault, and such cross faults or fractures lie in the moving block of the main fault system and indicate a change in strike or dip of the main fault. It has been found that each kind of change tends to produce definite effects and that careful study of the evidence can often suggest the exact type of change.

Jan 1, 1928

By H. H. Keller, E. J. Couch

Damage to production wells subjected to the high temperatures associated with in-situ combustion projects has been a problem since the advent of this thermal recovery technique. Injection of water down the annulus of hot wells has been successfully utilized for cooling and prolonging the life of such wells. A mathematical model that is suitable for predicting the effectiveness of cooling water in a particular application is developed. Typical results for practical ranges of the various parameters involved are presented. INTRODUCTION In the normal course of in-situ combustion operations, highly damaging conditions develop in the production wells as the combustion zone approaches, and these wells are subjected to high temperatures (up to 1500F). The resulting well damage is recognized as one of the more serious operating problems unique to the in-situ combustion process. Even in operations where well completions have been specifically designed to cope with this problem, the question arises as to how this destructively high temperature can be kept within tolerable limits. A simple and economical approach to this problem is to circulate cooling water down-hole. This method has been used with some success in shallow reservoirs. At greater depths, however, the heat exchange with the overburden surrounding the well and between the fluids in the tubing and the annulus tends to equalize the temperatures of the two fluid streams so that the cooling capacity delivered to the bottom of the hole decreases with well depth. This method would provide no appreciable control over the bottom-hole temperature at great depths. In order to delimit the condition under which cooling by water circulation is effective, the wellbore temperature must be related to the water inlet rate and temperature; to the reservoir depth, production rate, and initial temperature; and to the combustion at at bot tom-hole depth. A model that meets these requirements and that will offer an approach for developing engineering solutions to practical design and operating problems is described in this paper. MATHEMATICAL MODEL Previous studies of temperature distributions include those for flowing wells1p2 and those for hot fluid injection. Adams and Haddenhorst 6 presented solutions for the down-hole circulation of hot oil in the treatment of paraffin-deposition problems. In this paper the thermal model presented by Ramey 4 is adapted to the flow system shown schematically in Fig. 1. Water at temperature Ti is injected at a rate wi and flows down the annulus outside the tubing. It mixes at bottom-hole depth D with the fluids produced at race w from the hot reservoir at temperature T. This mlxtureJ. of injected water and reservoir fluids flows up the tubing and is produced at the surface at TI,. In order to describe the temperature response in this system, we make use of the usual conservation of

Jan 1, 1969

By D. M. Deason, G. Y. Onoda

Phosphate clay wastes, as currently produced, leave montmorillonite clay in a highly dispersed and disintegrated form. Alternative processing, where the extent of swelling and self-disintegration of such clays is controlled or limited, may result in improved settling and consolidation behavior. In this study, a method to control montmorillonite dispersion, through preservation of clay tactoids, was examined. Through this process, significant improvements in settling rates and sediment solids concentrations were achieved in both pure clay systems and on simulated phosphate clay wastes.

Jan 1, 1985

By M. T. Abasov

The work suggests an approach to the problem of optimally planning the drilling and development of gas fields. The approach is based on systems analysis and allows a joint optimal choice of the total number of wells in the field, their spacing in the reservoir, the diameter of production tubing, drilling dynamics, the number and spacing of drilling platforms and well pattern schemes for each plat- form as well. The optimal solution satisfies the set of technical- economical requirements and provides a minimum value of discounted total expenditures (capital costs plus operating costs). A mathematical model of the problem is presented. This work represents an extension of the authors&apos; previous investigations that formulated and solved problems of optimal drilling of oil and gas deposits by directional wells [1] and problems of optimal control of the number of active wells in multi-reservoir oil and gas fields [2], [3]. For construction of the mathematical model we choose a range (Nmin, Nmax) of possible values of the total number of wells, N, which should be drilled in the deposit. Here Nmin, Nmax are minimum and maximum numbers of wells correspondingly, that should be drilled into the reservoir. N[€](Nmin = N1, ... N[o], ..., Nm = Nmax). For simplicity a one-reservoir gas field is considered. It is assumed that: (a) wells are spaced in the reservoir uniformly, (b) there is a certain algorithm providing a uniform spacing of the given number N[o] ([0]=l, . . . , m) of wells in the reservoir, (c) the diameters of the production tubing for all the wells are the same. The relation Qz (x), i.e. the dependence of the cumulative output of gas from the cumulative "well-years" of operations is constructed for each diameter dZ from the given range of diameters d1< ...< dr.

Jan 1, 1977

By Roshan Bhappu, Laszlo Dudas, Herman Maass

Introduction Chemical and mineralogical constitution play a very important role in the processing of ores because they dictate the method, either physical or chemical, for extracting the mineral or metal. Similarly, the mineralogical nature of the ore, especially the grain size of the valuable minerals, is very important in its processing. The fineness of the grain may be such that physical separation pro- cesses may be eliminated in preference to chemical techniques. In the past, very little attention has been devoted to the geo- logical and mineralogical occurrences which may be potential sources of ores by both the geologist and mineral processing engineer. On the one hand, geologists have devoted less attention to lower grade, complex mineral deposits, and, therefore, may have inadvertently curtailed an exploration 2rogra.m. On the other hand, the metal- lurgists have neglected to study in detail the geological environ- ments and mineralization of potential ores with the view of deter- mining the critical parameter that could assist in economically processing complex submarginal deposits. In the final analysis, a chemical processing technique converts the valuable metals to a mobile state under conditions similar to those which deposited originally in the host rock. The relationship between ore-genesis and chemical processing is close when the process of mineral or metal deposition in a particular ore deposit is understood--putting the metal in solution by reversing the process of deposition is re- latively easy. For this reason, some researchers and educators have been stressing the importance of ore-genesis, geochemistry, mineral equilibria, and ionic equilibria in studying and explaining the

Jan 1, 1974

By Sidney L. Wise, Walter Strache

While the installation of mine bulkheads to retain water under high pressure is by no means a rarity, the following points which arose in the designing and placing of two of these bulkheads may be of interest: The Hibernia magnetite mine, located about 40 miles west of New York, in the State of New Jersey, is partly fillcd with water. This mine is located on an ore lens, the outcrop of which is over a mile long. The ore has been mined from this lens from the surface to a depth of more than 1,500 ft. It was held desirable to separate the old workings from the new, and to allow the former to fill to the 850-ft. level. Two weak places existed between the new and old workings below this Ievel: namely, a temporary bulkhead on the 10th level and a rock bulkhead of indeterminate thickness on the 16th level. When the matter of allowing the old workings to fill was investigated, the fact was developed that if these old workings were filled, the bulkhead on the 10th level would be subjected to a water pressure of about 50 lb. per square inch, and that 200 lb. per square inch would act on the 16th-level bulkhead. As the above-mentioned barriers were not deemed of sufficient strength to permit of these pressures, it became necessary to design and install new bulkheads. Design As the 16th-level bulkhead was required to withstand a pressure of 200 lb. per square inch, it presented some difficulties. A careful consideration of the various types of mine dams now in use led to the adoption of a design of the form of a truncated wedge. In this, the pressure side of the dam is of greater area than the hack, so that the resultant action is similar to driving the wedge. By cutting generous skewbacks in the walls, roof, and floor, this type in reality becomes an invisible arch. The wedge feature tends to compress the materials in the bulkhead, thereby adding to its imperviousness.

Jan 1, 1915

By R. L. Tobie

The degree of automation that has evolved in the dumping and hoisting of ore at the 3A and 3B hoisting shafts of the San Manuel mine is discussed. Motormen underground now dump their own trains at shaft pockets with rotary car dumps which operate semiautomatically. The ore is then drawn out of the 1200-ton shaft pockets into measuring baskets in skip loading stations, loaded into bottom-dump skips, hoisted, and dumped into coarse ore bins on the surface, in a fully automated operation. In an underground control room on the 2075 level midway between 3A and 3B shafts, car dumping, skip loading, and hoisting systems are monitored on lighted control panels which mimic each step in the operation. Here skip loading and dumping are viewed on closed-circuit television.

Jan 1, 1972

By J. J. Knoerzer

A full-scale operational test was conducted on the Coaltek preheating and pipeline charging system at the Semet-Solvay Div. of Allied Chemical at Ironton, Ohio, for the purpose of determining whether a high-quality blast furnace coke could be made from blends containing at least 75% Illinois No. 6 Coal and at the same time reduce air pollution during the charging of the ovens. The coke produced had similar physical characteristics as compared to our conventional wet-charged coke, with the exception of smaller size for the preheat coke. Air pollution during charging was con- trolled and there were no serious operating problems. The coking time was reduced 25% from our normal 17 hr for wet charging to 12.8 hr for preheated charges. The blast furnace performance with preheat coke was satisfactory.

Jan 1, 1976

By T. D. Yensen

If the question should be asked at this time: "Does pure iron have allotropic transformations?" the reply would necessarily be, "We do not know." And it is doubtful whether anybody, anywhere, is in a position to make any other reply at this time, for the simple reason that pure iron has not yet been made and tested. The nearest approach to it contains either an appreciable amount of carbon or else an appreciable amount of oxygen (a few hundredths of a per cent.). But why be con-

Jan 1, 1929

EUGENE MCAULIFFE, St. Louis, Mo. (written discussion*).-When we undertook the development of the Kathleen mine, near DuQuoin, certain features greatly influenced the construction and underground development. The country is very flat, so that the usual gravity yard movement of empty and loaded coal cars would entail a very heavy fill at the empty-car end of the tracks, with some form of car-pulling arrange-ment to move the loads where it was practically impossible to provide. a gravity movement. So the yard was made level, except for 1000 ft. (304 m.) under the two tipples, where the cars are moved by gravity and controlled under the main-shaft tipple by four Fairmont car retarders. Both tipples are spread sufficiently to admit of introducing a narrow-gage track and locomotive. One 18-ton locomotive is at present employed in moving empties clown to a point above the main-shaft tipple and the loads off the track scales clown into the storage yard; ultimately a 25-ton loco-motive will be employed on the loaded side of the tipple. This form of car movement and control will admit of handling empty and loaded cars

Jan 11, 1919

By R. R. Wilson

THE Cassidy Colliery operated by the Granby Consolidated Mining, Smelting & Power Co., Ltd., is situated about 9 miles in a southerly direction from the city of Nanaimo on Vancouver Island. The coal seam worked, which is called the Douglas bed, outcrops in the western part of the property, clipping easteyrl, and is opened by a slope 7 by 14 ft. in the clear, and is timbered by 12 to 14-in. framed sets of timber, 4 ft. center to center. A separate manway provides for a traveling road and at the same time forms an intake airway. The general average of the dip of the seam at Cassidy is 18°, and varies in thickness from 1 to 25 ft., averaging about 8 ft. The main slopes follow straight down the dip a distance of 4545 ft. At the bottom of the main slope two rock tunnels were driven a distance of 1500 ft. to the south, cutting through a fault, and opening up an area in the same seam which is known as No. 7 South Section. The coal is found in this section at a vertical depth of 1560 ft., and is very soft and friable. The immediate roof is a strong, sandy shale overlain by massive sandstone while the floor is a light-colored shale, hard when freshly exposed. It does not soften materially oil exposure. In the folding of the coal measures a great thrust caused a movement along the coal seam as indicated by the slickensided nature of the coal. The floor has buckled and this has rolled and squeezed the coal-so that with rare exceptions it shows no normal bedding but curved slip planes, which frequently start at right angles to the floor, curving upward and then in the direction of the dip. As such planes are slickensided it is probable that there is a coating of clay which is more or less impervious to gas.

Jan 1, 1927

By J. O. Edstrom, G. Bitsianes

Parabolic rate constants were determined for the formation of wiistite by the solid state reaction between magnetite and iron. The reaction was diffusion controlled and inert marker studies indicated that the mass transport through the wiistite layer was accomplished by means of iron migration. Relationships between rate constants and self-diffusivities are discussed. The transport capacity for iron through dense wustite layers was found to be sufficient to carry on reduction, even in gaseous reduction processes. REDUCTION of iron oxides has been the subject of many investigations. Most of the work, however, has been done on rather crude material and there have been difficulties in correlating the data on a quantitative basis. The reverse process of the oxidation of iron has been studied more thoroughly and usually by starting from the pure metal. As a result, the mechanisms of oxidation are now fairly well known.It has generally been found that the oxidation of metals follows the so-called parabolic 1aw;Q hat is, when the oxides are formed as dense layers, their thicknesses are proportional to the square root of the reaction time. This parabolic law follows directly from Fick&apos;s first law of diffusion The flux, J, is defined as the quantity of diffusing substance passing per unit time through unit area of a plane at right angles to the direction of diffusion. This flux is proportional to the concentration gradient of the diffusing substance, and the factor D, known as the diffusion coefficient, is introduced as the proportionality factor with dimensions of (length)&apos;/time. If the flux is measured as the increase of thickness of the oxide layer (Ax) per unit time (t) and the assumption is made that the concentrations of the reactants at the phase boundaries of the layer are independent of time, Eq. 1 reduces to Integration of this expression yields the parabolic function ax = k . t. [31 The product of the diffusion coefficient and the concentration difference across the oxide layer is included in the constant k. When iron is exposed to a highly oxidizing atmosphere, the oxide phases are formed normally in a topochemical fashion, i.e., the interfaces between the phases maintain parallel positions to the original surface of the specimen. Above 570°C, the phases are orientated usually in the order of iron, wiistite, magnetite, and hematite, a condition in conformance with the requirements of the Fe-0 system. Below 570°C, the wiistite phase is unstable and has not been found as a normal constituent in the oxidation products of iron. There is a strong probability that continuous layers of the solid oxides are formed as the specific volumes of the phases increase in direct order from iron to hematite.&apos; , &apos; Regarding mass transport through dense solid oxide layers, Wagner&apos; has postulated that diffusion in oxides generally may be interpreted as migration processes of ions and electrons. There must be normally a concentration gradient across the growing oxide layer for diffusion to occur. This condition requires that there be deviations from the ideal stoi-chiometric composition of the oxide and accordingly deviations from the strict order of an ideal lattice. Such "lattice defects" include interstitial ions, cation and anion vacancies, quasi-free electrons, and electron holes and are decisive for all migration processes.&apos; Cations, anions, and electrons all may have some mobility in the oxides but the movement of one of the particles generally far exceeds that of the others. Previous work&apos;, 1,2,7 has shown that during the oxidation of iron the migration through the wiistite layer, and probably also the magnetite layer, is confined to the movement of iron ions. Migration through hematite, however, has been found to take place by oxide ion movement. These behaviors are in direct agreement with the type of vacancies present in the respective oxides. Reduction of Iron Oxides The gaseous reduction of iron oxides, like the oxidation of iron, takes place in a topochemical fashion at distinct interfaces between the appearing phases."-&apos;" Porosities might be expected in these reaction products, since their specific volumes are less than that of the starting material. Frank and van Der Merwe" have shown, however, that it is theoretically possible for nonporous layers to form if the degree of misfit in specific volume is less than about 15 pct. These aspects on porosity formation

Jan 1, 1956

By James F. Lewis

THE hematite iron ore mines east of the Hudson River are confined to a strip of country ten to fifteen miles wide, commencing on the south, near Fishkill, running northeast through Dutchess County, and striking the southeast corner of Columbia County, extending into Litchfield County, Conn., known there as the Salisbury mines, cropping out again at and near West Stockbridge, Lanesboro, and Cheshire, Mass., also in Bennington County, Vermont. The ores are found in beds or deposits and in veins, with a limestone ledge on one side and slate on the other, from six to thirty feet from the surface. Portions of it are quite solid, called rock ore, but

Jan 1, 1877

By Ying-Chu Hoh, Renato G. Bautista

The chemically based models previously developed to describe and predict the distribution coefficients and separation factors for several different single and multicomponent metal extraction systems are presented in a more general form in this paper. The degree of formation of the aqueous phase inorganic metal complexes, the extraction mechanism of the complexes, and the equilibrium constant for the extraction reaction are used in the development of the models. The concept has been successfully applied to extraction systems where the organic solvent extracts an ionic species and where the organic solvent extracts only the neutral species. In addition, a model to describe a system where the organic solvent is extracting several extractable species has been derived on the same basis

Jan 1, 1981

By R. L. Andelin, J. D. Knight, M. Kahn

Self-diffusion in single-crystal tungsten and diffusion of rhenium tracer in single-crystal tungsten have been measured over the temperature range 2660° to 3230°C by direct sectioning and radio-chemical analysis of W185 and Re183 and Re184 tracers. The initial radioactive layer was produced on the diffusion specimens by bombardment with 9.0-mev deuterons. Diffusion heating of the samples in high vacuum was accomplished by induction heating. Temperatures were measured by optical pyrometry, and the system was calibrated ALTHOUGH a considerable body of experimental information has been accumulated on self-diffusion in solids, the major part of the detailed work has by reference to the melting points of tantalum (2996°C), molybdenum (2620°C), niobium (2468°C), and rhodium (1966°C). The diffusion coefficients for the two systems, obtained by least-squares analyses of the data, are well-represented by the equations thus far dealt with relatively low-melting systems. Diffusion studies on the high-melting elements niobium,1 tantalum,2,3 and tungsten4&apos;5 have been limited to polycrystalline material, for which data interpretation and theoretical analysis are sometimes difficult. Only recently, a study has been made with single-crystal molybdenum.6 The present work deals with the measurement of self-diffusion in single-crystal tungsten at temperatures approaching the melting point (3410°c).7 Since the method chosen for producing the radioactive tracer layer-bombardment with deuterons—produced detectable isotopes of rhenium as well as of tungsten, the diffusion of rhenium was measured also.

Jan 1, 1965

By Joseph Chalmers, E. L. Rawlins, D. B. Taliaferro

PRoblems dealing with the movement or migration of fluids through porous beds have been the subject of much research. The subject is not peculiar to the production of oil and gas, as many investigators have studied the nature of this movement and its relationship to the problems of other industries. Darcyl conducted a series of experiments relating to the percolation of water through filter beds. King2 carried on an extensive series of laboratory experiments with the object of formulating some conception of the rate of movement of water through soils and sand strata in the drainage of surface water into underground channels and subsequent recovery of this water through wells drilled into the source beds for irrigation purposes. Slichter3 undertook a study of the same problem from a mathematical standpoint, and more recently Furnas4 has investigated the flow of gases through beds of broken solids with particular reference to blast-furnace operation. With specific reference to gas production, Muskat and Botset5 of the Gulf Research Laboratory undertook an experimental study to establish quantitatively the characteristics of and laws governing the flow of gases through consolidated and unconsolidated porous materials of fine texture with a view of predicting the performance of gas in an underground reservoir. There seems to be a general agreement that many of the relationships between the numerousfactors influencing the flow of fluids through porous materials are far too complicated to be attacked by analytical methods based upon a knowledge of hydrodynamics. For gases, the laws of

Jan 1, 1932

By A. Kenneth Schellinger, O. Cutler Shepard

Overgrinding, Or the breaking of ore particles into sizes smaller than required for liberation, is a first-magnitude problem in grinding for concentration processes. The conventional ball mill-classifier circuit used in commercial grinding produces mineral particles that are all ground to pass an upper size limit, while the proportion of very fine sizes, or slimes, is uncon rolled. Calculations based on measurements made in commercial plants which were grinding ore for flotation concentration indicate that about go pct of the energy used in grinding is consumed in useless overgrinding.1 In addition to accounting for the consumption of a large amount of energy, over-grinding is detrimental to the flotation process. Overground slime coats larger partitles and inhibits selective action by the flotation reagents on particles which by themselves could be separated very well. A further difficulty is that extremely finely ground minerals do not respond satisfactorily to flotation-collecting reagents, and both selection and recovery decrease markedly with particles finer than 5 to 10 microns.2 conventional classifier-ball mill circuits inherently tend to overgrind the valuable minerals more than the gangue minerals because most valuable minerals are of higher density and are softer and more friable than the gangue minerals. The rem- edy to this situation would seem to be a separating mechanism which would separate free valuable mineral particles regardless of size and density considerations and a mechanism which would operate in the grinding mill so that valuable mineral grains would be removed from the grinding machine as soon as they are freed. A consideration of these ideas led the authors to the conception of a simultaneous grinding and flotation mechanism. So far as the authors are aware, such a machine has never been tried, even on a laboratory scale. Development oF Apparatus and Experimental Method Apparatus development went through several stages before a really workable machine was devised. Work was started with a large cast-iron mortar 7½ in. in diameter and 8 in- deep. A cast-iron disk Was mounted on the end of a vertical shaft SO that it fitted loosely into the bottom of the mortar. On top of the disk four radial cleats ¼ in. high were bolted to agitate the ball charge as the disk, or impeller, rotated. The vertical shaft was driven at 100 rpm by a mechanism improvised from an old coffee-mill type of grinder. A hole was drilled into the bottom of the mortar through which compressed air was introduced for frothing. In operation, more charges of Ore which had been crushed to pass an 8-mesh screen were placed in the bowl along with water and suitable reagents. The impeller was then started and the compressed air turned On so that the ore was ground while being exposed to air bubbles. Mineralized froth was

Jan 1, 1949

ATHOUGH the open-hearth charge contributes CO, CO2, and water vapor to the combustion gases and absorbs oxygen from them, in the main the thermal effects in the melting charge and molten bath can be considered independently of those in fuel combustion, the latter being regarded simply as the source of any extra heat required to finish a heat of steel. First of all, it should be remembered that a large percentage of the heat supplied to the bath is furnished by oxidation of the various elements in the charge itself. If this charge consisted of 80 to 100 per cent of hot metal and the oxidation were obtained by blowing in air or oxygen, as is the case in the Bessemer converter, then the net heat absorption would be negative, that is, the bath would contribute part of the heat required to keep the melting chamber hot, in addition to that contained in the finished steel and slag. In actual open-hearth practices, probably the nearest approach to this is in the duplex furnace, charged with Bessemer-blown metal and some hot metal, where very little heat is required to complete the refining and nearly all the heat energy from fuel combustion is used to keep the roof and walls of the melting chamber up to around 2900 to 3000°F. (1600 to 1650°C.) so that the bath will not cool off during the refining. The other extreme is with all-cold charges containing around 80 per cent steel scrap and 20 per cent cast iron or cold pig iron, in which case a very large proportion of the heat in the bath at tap is supplied from the fuel combustion. THERMAL EFFECTS IN MELTTNG In the previous chapter it was pointed out that in a typical heat, the fuel furnishes about four million B.t.u. per ton of steel produced. The heat required for the metallurgical processes is not easily defined in useful manner (as is shown later), but it ranges downward from about one million B.t.u., depending not only on the charge but on the manner of calculation. In any event this requirement appears quite small in comparison with the heat furnished by the fuel and invites

Jan 1, 1944