Search Documents

By G. L. Tufford, R. L. Bleifuss

Low-grade manganiferous iron ores of Minnesota's Cuyuna Range, in general, do not respond to conventional mineral dressing techniques because of their fine-grained texture. Reducing these ores to magnetite with subsequent magnetic separation and flotation have not given satisfactory results because, in many instances, concentrate grade and manganese recovery are low. Metallization of iron and concurrent reduction of higher manganese oxides to MnO, as in the R-N process, followed by recovery of iron by magnetic separation and manganese by leaching, seems to be a technically feasible process. High-temperature x-ray diffraction studies show that solid-state reactions between iron and manganese, with the formation of intermediate iron-manganese oxides, occur during reduction and affect recovery of both iron and manganese from the final product. Solid state reactions also occur between FeO, MnO, and SiO, at temperatures as low as 900°C. The kinetics of these reactions are such that they become an important factor in the treatment of ores by the R-N process. These investigations suggest a temperature and gas composition cycle that would maximize both iron and manganese recovery. During the past ten years, iron ore shipments from the Cuyuna Range of Minnesota have decreased sharp1y. Because of adverse grade, structure, and cost, many Cuyuna ores are no longer competitive with high-grade foreign ores and domestic pellets. The low-grade manganiferous iron ores from the Cuyuna Range, in general, do not respond to conventional mineral dressing techniques because of their fine-grained texture. Reducing these ores to magnetite for subsequent magnetic separation and flotation has not given satisfactory results because concentrate grade and manganese recovery are often low. However, a technically feasible process appears to be metallization of the iron and concurrent reduction of manganese oxides to MnO with recovery of metallic iron by magnetic separation and extraction of manganese from the tailings by leaching. In 1962 the R-N Corp., with a grant from the Area Redevelopment Administration, conducted an amenability study of the metallization of manganiferous iron ore from the Cuyuna Range. The results of this preliminary investigation were sufficient to interest the Economic Development Administration in sponsoring further studies of the process with emphasis on secondary recovery of manganese from the nonmagnetic tailings. Inasmuch as the metallization process has considerable influence on the final form of the manganese - its texture and distribution between the magnetic concentrate and nonmagnetic tailings-the investigation included a study of metallization of the ore as well. Therefore, the investigation conducted at the Mines Experiment Station covered three interrelated phases: (1) laboratory R-N roasting studies and magnetic separation tests, (2) laboratory chemical extraction experiments of the nonmagnetic tailings, and (3) a mineralogical study of the crude ores and their various roast products. High-temperature x-ray diffraction investigation of the Fe-Mn-Si0,-0, system is the main topic of this paper and an extension of the mineralogical work. GENERAL GEOLOGY The Cuyuna Range is known for its complicated geologic structure, complex orebodies, and generally indifferent response to attempts at conventional beneficiation. Several geologists have made intensive studies of the Cuyuna Range, including Leithl (1907), ~darns' (1910), Zapffe3 (1925), Grout and Wolff4 (1955), and schmidt5 (1963), whose study was the most comprehensive of all. The Range is covered with glacial deposits - till, out-wash, and lake sediments -up to 250 ft thick. Bedrock stratigraphic units of the Cuyuna Range consist of three tightly folded Precambrian sedimentary formations. The lower unit is the Mahnomen formation, composed of 2000 or more feet of argillite, slate, siltstone, and quartzite. The middle unit is the Trommald formation, which varies from 45 to 500 ft in thickness and comprises the major iron-bearing formation. The upper unit is the Rabbit Lake formation, consisting of over 2000 it of argillite, slate, and interbedded lenses of lean iron formation. In the central part of the Cuyuna Range, the units have been folded into a series of

Jan 1, 1969

By John A. L. Campbell

Although there has been an increased interest in the electrokinetic properties of coal (1) research on the subject is still in an early stage of development (2,3,4,5,6,7) To the author's knowledge, no electrokinetic studies have been made on coal lithotypes - particularly anthracite lithotypes. This paper presents the results of an investigation of the double layer properties displayed at the anthracite/water interface (whole coal and lithotypes) as determined by streaming potential methods, It is hoped that this investigation and related future investigations will provide correlations from which the surface properties of any coal can be predicted and then related to surface dependent processes such as froth flotation and flocculation. Another aspect of this research, undertaken to determine the physical and chemical parameters necessary for anthracite lithotype differentiation, was previously published (8). The number of parameters involved, lithologic, organic and inorganic, and the wide divergence of these parameters within an individual coal limits the practical utilization of the results, however, the results are of value and of interest in guiding theoretical developments. Keeping the limitations in mind, the results are analyzed in terms of their application to froth flotation processes and are used to indicate the feasibility of making a lithotype separation by flotation.

Jan 1, 1969

By C. Cronquist

Since April, 1962, Shell Oil Co. has operated a peripheral line-drive waterflood of the 10.750-ft lower Tuscaloosa (Cretaceous) Denkman sand in the Little Creek field. Located in southwestern Mississippi in the lower Tuscaloosa trend, the field was discovered by Shell in Jan., 1958. Among the largest in the trend, the accumulation is controlled stratigraphically and occurs in an extensive series of alluvial-point bar deposits across a nose that dips gently to the south. The crude oil is 39" API gravity and was highly undersaturated at initial conditions. Early production behavior indicated a depletion drive with slight water influx; primary recovery wm estimated to be 25 million bbl, or 24.5 percent of stock-tank oil originally in place. A.s a result of a favorable mobility ratio and remarkably uniform rock properties, the volumetric sweep eficiency in the waterflood has exceeded 90 percent. Despite the high connate water saturation (56 percent), the displacement efficiency by water injection has been quite efficient, contrary to traditional concepts. Based on observed field flood-out performance, ultimate recovery is calculated to be 46 million bbl. As anticipated, the production rate began declining during 1964 due to a continu ing reducrion in the number of producing wells as flood fronts advanced across the field. Cumulative recovery as of Jan., 1968, was 44.8 million bbl; waterflood operations ~hould be complete by 1970. Introduction Most waterfloods described in reservoir engineering literature involve pattern operations, the most common of which is the five-spot pattern. Only occasiona'lly are linear drives described, even though there probably are increasing numbers being put into operation. Increasing use of linear floods may reflect the accelerating trend towards early application of fluid-injection programs when linear drives are more efficient, as was the case at Little Creek. However. the Little Creek operation is unusual in several respects. It is one of a few successful waterfloods conducted in sands with connate water saturations approaching 60 percent, and it is among the deepest successful water-floods being operated anywhere. Development The Little Creek field was discovered in Jan., 1958, in the lower Tuscaloosa trend in southwestern Mississippi (Fig. 1). The discovery well, Shell-Lemann No. 1, was drilled on a seismic closure about 2 miles southeast of lower Tuscaloosa production at Sweetwater. The well was completed in the Denkman sand at 10,752 ft, and on initial potential it flowed 588 BOPD of 39" API crude on a %+-in. choke; psi was 730 and GOR was 442:l. Development proceeded rapidly on 40-acre spacing, and by the end of 1958 the field was producing approximately 9,100 B/D from 56 wells. Almost all this production came from the northern half of the field. The southern part was discovered in Nov., 1958, at a location almost 2 miles from previously established production. Subsequent drilling established an apparent conneotion about half a mile wide between the twd areas. Development of the field was practically complete by 1961 with the drilling of 155 producers and 35 dry holes. Some early wells were completed open hole but moslt are completed with casing cemented through the productive interval and perforated for production. Geology The lower Tuscaloosa structure in this area is a north-south nose with maximum dips of about 2" on the flanks. There is no discernible faulting at the producing horizon. Productive limits of the field are shown in Fig. 2, which is contoured on a marker just above the main productive zone. A common water level at 10,415 ft subsea was logged at both the northwest and southeast ends of the field. There is a gross oil column of nearly 100 ft (Fig. 2). Since there is less than 40 ft of closure, it is apparent that bhe accumubtion is controlled stratigraphically, being limited by a sand pinch-out across the creslt of the nose. The total produc-

Jan 1, 1969

By R. M. Brown, W. J. Murphy, B. M. Kapadia

An investigatiott was conducted to study the influence of nitrogen, titanium, and zirconium on the boron llardenabilzty effect in a low-carbon constructiona2 alloy steel. The experimental steels investigated exhibited a significant variation in hardenability, the variation being dependent on the interactions of boron, titanium, and zirconium with the nitrogen. Only the boron not combined with nitrogen was effective in increasing hardenability. Titanium, and with lesser effectiveness zirconium, combined with available nitrogen, thereby protecting the boron. The hardenabil-ity effect mas related to an empirical expression for the "effective" boron content, P, deduced from experimental evidence of these interactions. The hardenabzlity effect reached a maximum at about 0.001 wt pct 0, and decreased somewhat as P increased further. The physical understanding of this relationship is discussed. FOR many years boron has been added to steels to obtain high hardenability. Although a great deal of research has been conducted on boron-treated steels, certain aspects of the boron hardenability effect have not been fully understood. For instance, the magnitude of the hardenability effect has been observed to vary markedly, depending on the steelmaking technique, even when the amount of boron in the steel was essentially constant. Furthermore, the optimum amount of this element to be added has not been definitely established. A better understanding of the boron hardenability effect is essential because too small an addition of boron is likely to be ineffective, while an excessive amount can cause brittleness'' and hot shortness. The findings of earlier investigations have shown that the hardenability effect cannot be consistently related to the amount of boron added or retained in the steel. Grossmann observed that in a 0.60 pct C steel the hardenability increased to a maximum with mold additions up to about 0.0025 pct B and then decreased with larger additions. Other investigators5 likewise reported a maximum in the hardenability at about 0.003 pct B. Crafts and Lamont, however, found that in commercial open-hearth heats of medium-carbon steel the hardenability increased linearly with boron up to 0.001 pct and remained essentially unchanged with larger percentages up to 0.006 pct. Other investigators7,' also observed a rather constant hardenability effect in the range about 0.0005 to 0.0035 pct B. These observations and other evidence suggest that the effectiveness of boron in increasing hardenability probably depends, in addition to the amount, on the form of boron retained in the steel, this form being influenced by the presence of other elements. Both oxygen and nitrogen apparently exert the strongest influence on the hardenability behavior, since, at the temperature of liquid steel, boron readily combines with these elements, thereby losing its effectiveness as most experimental evidence seems to indicate. For consistent recovery of the boron effective in increasing hardenability, it is necessary that the oxygen and nitrogen in the steel be either reduced to extremely small amounts by the steelmaking practice or neutralized by combination with other elements before the addition of boron. The importance of achieving adequate deoxidation prior to the addition of boron in order to realize the full hardenability effect of boron has been sufficiently emphasized by earlier investigators. Digges and Reinhart' and others have investigated the role of nitrogen and have shown that nitrogen also interacts with boron and reduces or nullifies altogether its effect on hardenability. Moreover, their work also demonstrated that the addition of strong nitride formers such as titanium and zirconium reduce the deleterious effect of nitrogen on boron hardenability by combining with nitrogen to form stable nitrides. Another element which has a pronounced influence on the boron hardenability effect is carbon. It has been shown7'10 that the hardenability effect of boron diminishes with increasing carbon content, and becomes almost negligible at the eutectoid composition. This observation is useful in comparing the potential increase in hardenability from boron of steels with different carbon contents, but is not relevant to a study of the effects of normal steelmaking variables. The amounts of oxygen and nitrogen in steel vary with the steel composition and steelmaking practice employed. Most commercia1 low-alloy steels are fully deoxidized by the addition of silicon and aluminum, or other strong deoxidizers, which adequately protect the boron from oxidation. In addition, one or more of the elements such as titanium or zirconium are usually added, either separately or in combination with boron, in the form of complex ferroalloys, to protect boron from combination with nitrogen in the steel. However, the actual amount and type of addition employed for a given processing requirement are usually selected by trial and error, and have a rather limited range of applicability. As a result, substantial variations in the hardenability of boron-treated steels are often observed in practice, particularly when the nitrogen content of the steel is a significant processing variable. These variations might therefore be reasonably attributed to the interactions between boron, nitrogen, and titanium or zirconium present in the

Jan 1, 1969

By S. James Campbell

Ladies and Gentlemen: Never in the history of our mining industry has the emphasis on public relations been accelerated as much as it has in the last few years. Knowing of your keen interest in this subject I consider it a great privilege that your program committee has asked me here to discuss the crushed stone segment of our industry approach to this important part of our daily business lives. As you are aware, crushed stone operations are present in almost every segment of the country wherever aggregates for construction projects are required. The tonnage of crushed stone produced is second only to sand and gravel - another source of aggregates - and this together with sand and gravel amounts to over half of the tonnage of all mined products in the United States. What is unique about this industry that will be of interest to all of you in analyzing how they have approached Public Relations? The fact that it is so wide-spread is of course obvious, but perhaps a more significant nature of this segment of the mining industry that has brought it more in the limelight of public interest and on a larger scale is the location of a large part of the quarries quite close into the urban area and population centers where you have the greatest demand for aggregate products.

Jan 1, 1969

By W. B. Morrison

The principal factors influencing the total percent elongation of a lead-tin eutectic and several low-alloy steels which exhibit superplasticity were investigated. These factors are: a) Strain-rate sensitivity of the stress (m). b) Specimen geometry; in particular, diameter-to-length ratio (d0/l0), and surface irregularity (e.g. notches). A feature of the tensile deformation of a superplastic alloy is the early appearance of a neck which continues to extend throughout the test. As a result the total elongation is directly related to the diameter-to-gage-length ratio. The strain-rate sensitivity of the stress varies during extension, mainly because of microstruc-tural changes. A satisfactory correlation exists between the minimum strain-rate sensitivity and total elongation, as indicated in the equation shown below. Notches cause a considerable reduction in total elongation and their effect is greatest at high values of strain-rate sensitivity. An initial notch depth exists below which there is no appreciable effect on elongation. An equation relating elongation to strain-rate sensitivity and specimen geometry is proposed, THE total percent elongation of a tensile specimen is usually regarded as a measure of superplasticity. However, little attention has been given to the fact that total elongation is also a function of specimen diameter and gage length, even though the importance of geometry has long been recognized in the tensile testing of materials in which elongations are relatively small.* In the present study, the effect on superplas- tic extension of the ratio of specimen diameter to length was investigated and an analysis was made of strain distribution along the gage length. Superplastic alloys are characterized by having a flow stress sensitive to strain rate but relatively insensitive to strain.2"' In an earlier study,5 it was found that the strain-rate sensitivity of several low-alloy steels changed during the test and that the minimum value correlated best with total elongation. In the present study, the variation of strain-rate sensitivity during the straining of a lead-tin alloy was investigated. EXPERIMENTAL PROCEDURE Lead-tin eutectic alloy (32 pct Pb 68 pct Sn), made from high-purity lead and tin, was cast in the form of 1-in. diam rod. The rod was cold-rolled in stages to 0.25 in. diam and then swaged to 0.125 in. diam. Samples were cut from the rod at various stages of the mechanical working process. Tensile test specimens were then made by attaching threaded steel ends to the rods by an epoxy-base thermosetting adhesive which required a setting treatment of 2 days at room temperature. The rods were seated in the steel ends in holes approximately 0.01 in. oversize. The test pieces thus made were of various diameters and gage lengths. These were stored at a temperature of about -70°C (-94°F) until required for testing. The distribution of strain along the gage length of a specimen was determined at various stages of the tensile test. The lead-tin alloy was superplastic at room temperature and direct observations during testing were simple. The gage length was divided by reference marks into five initially equal units. These reference marks were made with ink and were reinforced during the test when the initial marks became faint. Photographs were taken, at intervals, of the deforming specimen and measurements of the elongation in each of the gage units were made on these photographs. Tests were also done on several superplastic low-alloy steels whose properties were described earlier.5 The chemical compositions of these steels are given in Table I. A diagram of the notched tensile specimen used in the steel tests is shown in Fig. 1. The specimens were tested at 900°C (1650°F) in a furnace through which a mixture of He + 2 pct H was continuously circulated.5 RESULTS Strain Distribution. Approximately 20 tests on lead-tin alloy specimens were conducted to determine the strain distribution during the test. An example is shown in Fig. 2 of the strain distribution in the gage

Jan 1, 1969

By S. C. Jones, J. A. Davis

This paper describes displacement mechanisms of micel-lur solution slugs, displuced by a thickened water "mobility buffer", in a glass micromodel and in consolidated Berea sandstone cores. Colored motion pictures, taken through a microscope, recorded interactions on a pore-to-pore bash in the micromodel. Production and differential pressure data from consolidated cores previously waterflooded to residua1 oil saturation revealed displacement mechani.sm.s macroscopically. Oil is displaced miscibly, while interstitia1 water is displaced immiscibly by the injected micellar. solution slug. Part of this water is dispersed and carried near the lead ing edge of the .slug, and some may remain as a residual saturation. Thickened water displaces any residual water. It also emulsifies with the. slug material, thereby displacing it. The displacement sequence forms banks of oil and water with relatively constant fractional flows, saturations, and mobilities. The mobility of oil and water flowing ahead of the .slug defines .slug viscosity required for stable displacement. Equations are presented that describe. several aspecis of the displacement flow behavior: oil breakthrough, oil cut during production of the stabilized bank, breakthrough of banked water and the resulting decreased fractional flow of oil, fluid mobilities, etc. Breakthroughs, calculated from the equations, are compared with experimental data. Slugs of micellar sollution, ranging from 1 to 5 percent PV, produced unusually high oil recoveries (up to 100 percent) in previously waterflooded consolidated cores. Investigation of the effect of mobility buffer size on oil recovery indicated that recovery is reduced in 3-in. X 4-ft cores for mobility buffer sizes .smaller than 50 percent of the pore volume. Introduction A new oil recovery process,* conceived in 1962, utilizes a slug of micellar solution' that has sufficient viscosity to avoid an unfavorable mobility ratio with respect to the oil and water it displaces. These micellar solutions are composed of hydrocarbons, water, and surfactants, and may contain electrolytes and co-surfactants. The micellar solution is displaced by a "mobility buffer". The mobility buffer is a bank of reduced-mobility fluid, preferably an aqueous polymer solution. The entire system is displaced by unthickened water. This paper describes some of the microscopic and macroscopic displacement mechanisms observed during laboratory development of the fluids for a potential field test. Microscopic phenomena were observed photographically in a specially constructed glass flow model and macroscopic data were taken from constant rate, tertiary displacements conducted in Berea sandstone cores. Qualitative Description of Micellar Solution Flooding This section qualitatively describes displacement mechanisms that occur when a slug of micellar solution is injected into a previously waterflooded core. The slug completely removes oil from the portion of core it contacts, and banks oil in the process. The oil saturation in this bank and the flowing WOR reach definite, fixed values that are determined by water and oil mobilities and slug characteristics. This zone of constant WOR and oil saturation will be called "stabilized oil bank" in the following discussion. When this stabilized bank reaches the outlet end of the core, the oil cut jumps from zero to a constant value equal to the fractional flow of oil. Saline water has little or no solubility in the slug. Because of this. the slug displaces in-place brine immiscibly. During slug injection, most of the brine is displaced ahead of the slug, some is carried along in the leading portion of the slug, and part of the brine may become immobile. The immobile, residual brine is later miscibly displaced by thickened water. Displacement of all the oil and only part of the water during slug injection results in a higher fractional flow of oil ahead of the slug than occurs when all the water is displaced after injection of thickened water is begun. The slug spontaneously emulsifies fresh (low-salt content) water. By emulsification, the slug can become infinitely diluted, and hence totally displaced, by thickened water. Fluid saturations in the core are shown schematically in Fig. 1. Parts A and B show conditions before and after the start of the thickened-water injection, respectively. Since thickened water displaces any residual brine by-

Jan 1, 1969

By Colin M. Sargent

ALTHOUGH annealing twins are frequently observed in many fcc metals, their occurrence in aluminum is relatively rare. ~ahn' in his review of twinning has listed only a few references to observations of twins in aluminum, e.g., Refs. 2 and 3. They have also been shown to occur in evaporated aluminum layers.4 During the present work, several annealing twins were studied in aluminum. The specimens of 1099-grade aluminum had the following thermomechanical treatment: deformed 90 pct by rolling, partially re-crystallized, further deformed 60 pct to a final thickness of 100 p, then annealed for 24 hr at 120°C. This treatment produced several annealing twins—-about ten per electron microscope specimen. The specimens were produced by the window technique and examined in a Phillips E.M. 200 operating at 100 kv. A typical twin boundary is shown in Fig. 1. For several of the twins studied the twin plane could be tilted so that it was parallel to the electron beam, e.g., Fig. 2. The associated diffraction pattern, Fig. 3, shows the twinned relationship between the grains. The twinning plane in each case was (111). Use of a reflection common to both the twin and the matrix,* i.e., using reflecting planes parallel in the twin and the matrix, the coherent twin boundary becomes invisible and only the noncoherent segments of the stepped boundary are seen, e.g., Fig. 4. Trace analysis of the boundaries showed that the long straight portions were invariably the twin plane; i.e., these portions are coherent. The planes of the shorter segments are shown by Fig. 5 to be (551 1, (7111, and {211).

Jan 1, 1969

A modified liquation technique was developed for recovering tin from tinhouse scruff metal or hardhead containing about 10 per cent iron and 15 per cent occluded flux, palm oil, and moisture. This was effectedby heating the scruff metal to 950°C followed by rapid cooling to suppress the formation of FeSn2 and FeSn, and then subjecting it to the ordinary liquation and drossing processes of refining. By this method it was possible to recover about 83 per cent of the original tin content and, with subsequent smelting of the irony drosses, an overall recovery of 92 per cent was obtained.

Jan 1, 1969

By James E. Lawver, James L. Wright

This paper discusses the design and calibration of a Faraday pail for measuring electric charge. The paper also shows that at least for two minerals, quartz and calcite, the phenomenon that Johnson termed "reversibility" can be explained in terms of the contact electrification between the minerals and the metal rotor of an electrostatic machine. Each year the free world produces about 13 million tons of mineral concentrates by electrical separation. However, despite the rather general acceptance of electrical concentration as an industrial process, research in this area has lagged far behind the efforts devoted to competitive processes such as froth flotation. The purpose of this paper is to describe the design and calibration of a Faraday ice pail for measuring charge density on mineral grains and to show some of its applications in the area of electrostatic and electrodynamic research. THE DESIGN AND CALIBRATION OF FARADAY PAILS FOR ABSOLUTE CHARGE MEASUREMENT The electric charge on mineral grains at a given time during an electrical concentration process is de- pendent on many factors and cannot, in general, be accurately calculated a priori. It is thus important to devise a method of measuring absolute charge. One method of measuring electric charge is to note the potential rise of an electrometer when charged particles drop into a Faraday pail. Two types of Faraday pail have been constructed and calibrated. The first type, Faraday Pail I (Fig. 1), is a vertical pail originally designed to measure the charge due to contact electrification between mineral grains and a metal rotor or due to conductive induction when mineral grains are passed over a rotating cylinder in the presence of an electric field. The second type, labeled Faraday Pail II (Fig. 2), is a horizontal pail designed to determine the charge distribution of mineral grains after they pass through the separating zone of the electrical concentrator shown in Fig. 4. The main advantage of the horizontal pail is its low head-room requirement and the long opening which enables the experimenter to sample the entire width of the stream of minerals being separated. The Faraday pails were calibrated in the following manner: A calibration head was constructed in the form of a hollow brass sphere that could be held in an insulated metal cylinder by vacuum (Fig. 1). The capacitance of the sphere was calculated by measuring the capacitance of the sphere and cylinder combined and that of the cylinder alone and subtracting the latter measurement from the former. The sphere was then charged to a known potential (V) and allowed to drop into the Faraday pail which was attached to a Keithley Model 610A electrometer. This instrument has an accuracy of 2% full scale and has

Jan 1, 1969

By B. H. Caudle, L. G. Davies, I. H. Silberberg

This paper presents a method of predicting the recovery and performance of a five-spot steam injection project, in which a realistic approach to pattern sweepout efficiencies is made. Published methods for radial systems were modified for the five-spot pattern by approximating the stream lines with straight lines radiating from the injection well and then converging to the producing well. In each radial segment, the position of the steam front and the temperature profile ahead of the steam front were determined by heat balance equations, which included an estimation of heat losses to surrounding formations. The location of the saturations behind the cold water front was determined from a Buckley-Leverett solution to the material balance equation. Results from this program show steamflood recovery in a five-spot pattern to be considerably less than that predicted for true linear or radial flow systems. For a specific reservoir containing 900-cp oil, a steamflood in a purely radial flow system was predicted to recover more than 75 percent of the original oil in place when 2 PV of water had been injected as steam. A five-spot steamflood with otherwise identical properties was predicted to recover 10 percent of the original oil in place when 0.15 PV of water had been injected as steam and to recover almost no oil thereafter. A cold water five-spot flood in this system was predicted to recover approximately W percent of the oil in place with I PV of water injected. For a five-spot pattern in an example reservoir with 10-cp oil, steam injection similarly showed lower ultimate recovery than water injection but no improvement in recovery rule. Introduction The thermal recovery method considered in this study is steam injection in a five-spot pattern. Pattern steam injection has been given little attention in the past, possibly because of some rather obvious disadvantages. Unless steam temperature is maintained throughout the entire swept area, the process will revert to simple waterflood with all heat being lost prior to reaching the oil bank. Also, the oil viscosity reduction takes place near the steam front and not around the producing wellbore, so that low producing rates must still be endured. This is the reason for the success of the steam stimulation, or cyclic injection, in which the fluids are produced from the same well used for injection. On the other hand, steamflooding can offer some advantages. Oil displacement is by four methods: (1) mechanical displacement by the condensed water, (2) viscosity reduction of the crude oil, (3) swelling of the crude oil, and (4) distillation of the crude oil in the steam zone. Although dependent upon the crude, laboratory experiments have shown displacements up to 80 percent by steamflooding. In addition, steam is a good heat transport medium, since it is cheap and has a high heat content. Previous Investigations Previous publications have reported methods for predicting recovery in a steamflood for linear and radial systems. Since no pattern sweep efficiency is taken into consideration, the recovery even from a radial system must be greater than from more realistic geometries such as the very common five-spot patterns. Probably the broadest coverage is given by Willman who reported experimental results and offered a method of predicting recovery for a radial flow system. They concluded that both hot water and steam injection recover more oil than an ordinary waterflood, and that steam injection could yield recoveries "as much as 100 percent greater than by water flood." They also concluded that both the heat requirements for a reservoir and the residual oil remaining in the reservoir after steam injection were independent of the amount of oil originally in place, that short exploitation times were desirable, and that a high percentage of net sand in the reservoir with a high initial oil saturation was desirable. The method assumes that the flood occurs in three concentric cylindrical zones: (1) an inner steam zone, (2) a central hot water zone, and (3) an outer cold waterflood zone. Displacement in the steam zone is based on laboratory-determined residual oil saturations while the hot water and cold water zones use the conventional Buckley-Leverett equations. Although the results shown by Willman et al. are for a radial system flowing out from the well to an assumed external circular boundary, their equations did

Jan 1, 1969

By Edwin F. Brush, John Chipman

Published data on the activity of carbon in binary and ternary austenite at 1000°C are reviewed. The composition variables are . The coefficient, Vj, has the value for substitutional elements but may be assigned a ualue -1 for silicon to effect a simplification on the mathematical treatment. The activity coefficient PC = is obtained from gas equilibrium data. For the ternary systems studied the Henrian activity coefficient is given by the expression: The principle advantage in cornparison with the analogous expression in terms of atom fractions is found in the fact that for most systems the final term and in many the last two terms are zero. Values of the interaction parameters are tabulated and the graphical comparison of the equation with experirt~ental data is sho,wn in several figures. The thermodynamic properties of the solid solution, austenite, are of considerable importance in the heat-treatment of alloy steels and in other aspects of ferrous metallurgy. Early studies embodied in the Fe-C diagram have been extended to include other binary and some ternary diagrams. Our best hope of obtaining a useful thermodynamic treatment of reactions in complex alloy steels will not be found in quaternary and quinternary phase diagrams but in determinations of activities and interaction relations among the several solute elements. The foundation for such a development was laid by smith' in his early studies of the activity of carbon in Fe-C alloys and his subsequent work on Fe-C-Si, Fe-C-Mn, Fe-C-Ni, and Fe-C-Co solid solutions.2"4 Other observers have also made noteworthy contributions and these will be discussed and correlated here in the light of a somewhat simplified mathematical treatment of solute interactions. Fe-C AT 1000°C In a recent review of the thermodynamic properties of binary Fe-C austenite it was shown that the simple mathematical treatment employed by smith' was capable of describing all the published results on this solution. The treatment utilizes the atom ratio, yc = nC/nF,, rather than the atom fraction. The activity of carbon is proportional to the equilibrium gas ratio, either measured on a scalk in which the activity of graphite is taken as unity or, alternatively, aC may be set equal to yc at infinite dilution. In either case the ratio aC/y = (PC, the activity coefficient. It was found that the experimental data of smith1 and those of Diin-wald and wagner; Bungardt, Preisendanz, and Lehn-ert,' and Scheil, Schmidt, and Wiinnings at temperatures of 800" to 1200° C as well as reliable data on the solubilities of graphite and cementite could be represented by the equation for which graphite is the standard state: The data on alloyed austenite have been obtained at 1000°C. For this temperature, the "Henrian" activity coefficient (which is unity at infinite dilution) is: FOr an interstitial solute such as carbon in austenite it has been shown by statistical mechanicsg that the activity in the infinitely dilute solution is proportional to the ratio of the number of lattice sites occupied by carbon to the number of yet unfilled lattice sites. A variable zz proportional to this ratio serves as a useful measure of concentration:" in which b is the number of lattice sites provided by each atom of solvent; in austenite b = 1. The Henrian activity approaches zz at infinite dilution and the ratio a is the activity coefficient. The effect of a change in concentration is then given by: It has been shown further that in some systems the derivative in Eq. [4] remains constant over a wide range of concentrations. In such a case second-order terms become negligible and the Henrian activity coefficients is:

Jan 1, 1969

By Ben-Zion Weiss, Melvin R. Meyerson

FATIGUE crack propagation in some aspects can be viewed as being a result of localized plastic deformation concentrated near the tip of the crack.' Deformation is influenced by microstructure which in turn can affect the fatigue crack growth significantly. To study the effect of localized microstructural changes on fatigue crack propagation, cantilever-type notched specimens were subjected to cyclic bending at constant load amplitude. The extent of fatigue crack propagation was obtained by measuring the length of the crack by periodic observation with a microscope on the polished side of the sample,2"4 and these data were used in preparing the curves in the figures which follow. Figs. 1 (solid lines) and 2 show experimental results obtained in austenitic type 302 stainless steel containing higher than standard carbon (0.24 pct C) and 310 stainless steel. Both steels were homogenized for 8 hr at 1120°C and then water-quenched in order to prevent the precipitation of carbides. Fig. 3 shows experimental results obtained on 9440 low alloy steel in the normalized condition and in the quenched and tempered (580°C) condition. Indications of microstructural influence can be seen in scattering of the experimental data. The degree of scattering depends on both the microstructure and the amount of cyclic stress applied to the sample. For microstructures which are more easily deformed plastically, e.g., normalized or annealed as compared with hardened and tempered structures, the scattering is greater. Similarly, higher stresses produce greater scattering in the results, regardless of whether the cause of the stress increase is due to initial loading conditions or the growth in crack length. Scattering is believed to be a result of partial redistribution in the stress field around the tip caused by plastic deformation. This opinion is borne out by much smaller scattering of experimental results in the austenitic 302 high-carbon (0.24 pct C) steel. In this steel, plastic deformation in the neighborhood of the crack causes partial mar-tensitic transformation of metastable austenite,5 which in turn restrains further plastic deformation. As a result, the stress redistribution around The tip is reduced. Partial martensitic transformation was confirmed

Jan 1, 1969

By Edward W. Mehal

This paper presents a review of the technologies which have been used in the application of III-V compound semiconductors to integrated circuits and arrays. These materials have properties which make them useful for various devices such as: light emitters, sensors, microwave sources, and microwave diodes. Technologies for incorporating these devices into integrated circuits have been reported and processes developed for fabricating planar devices using selective epitaxial deposition or selective diffusions. Isolation methods utilizing semi-insulating GaAs, oxide isolation, and ceramic insulation have also been reported. These techniques, and the devices and circuits produced or proposed are discussed. AFTER the invention of the silicon-integrated circuit, methods for utilizing compound semiconductors for integrated circuit applications were proposed. The scope of applications was potentially much broader because of the range of properties available from these materials. There also was the opportunity of coupling these properties with germanium and silicon devices to realize functions and circuits which could not be produced with silicon monolithic circuits. Table I exemplifies the range of electrical properties available in III-V compound semiconductor materials which are currently being widely used. A wide range of sensor and emitter applications result from the range of band gap. The band structure of GaAs and GaAsxP1-x permits their use as microwave oscillator source, and the high electron mobilities further facilitate their utility in microwave devices. The concept of "integrated functions"1 results from the availability of these materials and methods for utilizing their special properties. Heteroepitaxial growth allows the fabrication of a monolithic block of these materials. Semi-insulating GaAs permits the attainment of electrical isolation between components in a monolithic block without resorting to p-n junction biasing or oxide isolation methods. An "integrated function" is a unit which can perform a system or subsystem role and perform a number of electromagnetic functions. These functions could include sensor or input transducer, signal processing, interconnections, and control or output function. Two examples which demonstrate this concept are an optoelectric processor and a microwave receiver front end. The optoelectronic processor, Fig. 1(a), would consist of a light sensor, signal processor, and output emitter. The sensor could be InSb or InAs which would be IR-sensitive. The signal from this sensor would then be amplified and transmitted to the light emitter. The amplifier could utilize GaAs bipolar or field effect transistors. A Gap emitter would then produce visible radiation. The microwave receiver front end, Fig. l(b), would consist of a local oscillator section and a mixer section. A signal input from an antenna is mixed with the signal from the local oscillator. The local oscillator signal is produced by a Gunn oscillator. The single-ended mixer utilizes one Schottky barrier mixer diode. The IF signal would then be amplified further and suitably displayed. A further extension of the capability of utilizing the

Jan 1, 1969

By Joseph W. Town

The Bureau of Mines conducted studies related to SO2 air pollution to determine attritioning rates, SO2 sorption rates, and sulfur loads that could be obtained on commercial alkalized alumina sorbent pellets. Fluidized-bed attritioning rates ranged from 0.025 pct/hr for alkalized alumina with a crushing strength of 4 kg to 0.075 pct/hr for 0.5 kg crushing strength mate¬rial. Airlift attritioning rates ranged from 0.50 pct/hr for 3 kg crushing strength alkalized alumina to about 3 pct/hr for 0.5 kg material. Attritioning rates for the commercial alkalized alumina were comparable to those obtained for sorbent pellets prepared in the Bureau of Mines laboratory. Sorption rates were related to S02 concentration in flue gas, temperature, and presence of nitrogen oxides in the gas stream. Sorption rates at 300° C were 0.35 X 10-6 gS/gp/sec (grams sulfur per gram pellet per second) in 0.045 pct so, gas, 5.1 x 10-5 gS/gp/sec in 0.34 pct SO2 gas, and 65 X 10-5 gS/gp/sec in 10 pct SO2 gas. For the 0.34 pct S02 gas, sulfur loads of 0.10 gS/gp (the projected load for regeneration) were obtained in 47 min at 130° C and in 116 min at 300° C. The presence of either NO or NO2 in the 0.34 pet S02 gas increased the SO2 sorption rates 2 to 3 times at 300° C, but had no effect at 130° C.

Jan 1, 1969

By E. Rudy, St. Windisch

The only complete phase diagram investigation of the Ti-W system is by Maykuth and coworkers,&apos; Fig. 1. Although previous work by Gonser2 indicated complete miscibility, later investigations3°5 essentially confirmed the diagram depicted in Fig. 1. The present study was undertaken because preliminary results on metal-rich ternary Ti-W-C alloys indicated complete solid solubility between 0 titanium and tungsten at temperatures above 1300°C—in contradiction to the presently accepted diagram. The powdered elements, as well as crystal bar titanium and tungsten sheet, were used in the preparation of the experimental alloys. The iodide titanium, obtained from Foote Mineral Co., Exton, Pa., had a total impurity content of less than 410 ppm, of which 150 ppm were interstitials (H, O, N, C). The overall purity of the titanium powder (Var-Lac-Oid Chemical Co., New York) was better than 99.7 pct. Major contaminants, in ppm, included: 0, 800; N, 10; H, 1500; Fe + Co + Ni + Cu + Zn, 50; C1, 200. The measured lattice parameters of the titanium were a = 2.94A and c = 4.68,A. The tungsten sheet and the tungsten powder (Wah Chang Corp., Albany, Ore.) contained the following impurities (in ppm, values in parentheses refer to the sheet tungsten): Mo, 50 (70); 0, 140 (110); Fe, 20 (60); Ni, 20 (not determined); N, 110 (not determined); sum of other impurities, <60 (<100). Samples from the iodide titanium bar stock and from tungsten sheet were prepared by repeated melting of the chipped materials in a nonconsumable electrode arc furnace under high-purity helium. The melted alloys were heavily cored, and homogeneity of the alloys could only be achieved after prolonged heat treatments at subsolidus temperatures. The majority of the alloys were therefore prepared by cold compacting the well-mixed powders in steel dies and pre-homogenizing the compacts for 6 hr at 1300°C in a tungsten-element furnace. The vacuum was better than 10"6 Torr, but for additional protection the sample container was wrapped in zirconium foil. Both preparation methods led to identical results. The measurements of the solidus temperatures were carried oat in the Pirani-type furnace described in a previous paper.6 Incipient melting in alloys containing between 20 and 90 at. pct W was rather difficult to detect visually, and therefore a photoelectric transducer system7 was employed to indicate the phase change. For the investigation of the solid-state equilibria, the specimens were first homogenized for 2 hr at slightly subsolidus temperatures in the Pirani fur- nace and then reequilibrated at, and rapidly cooled (-100°C per sec) from, the selected equilibrium temperatures. After the runs, the alloys were analyzed microscopically and by X-ray diffraction. With the exception of spot checks for oxygen and nitrogen in processed alloys, no other chemical analyses were performed. However, as the weight changes of the alloys during processing were within 0.05 pct and the lattice parameters of indeqendently prepared alloy series agreed within 0.0015A, it is reasonable to assume that no significant concentration shifts with respect to the nominal compositions had occurred. The measured solidus temperatures, shown together with literature data in Fig. 2, ascend smoothly from

Jan 1, 1969

The geology of an area in north-western New South Wales, bounded by the South Australian and Queensland borders, latitude 32&#176; S. and longitude 14&#176; E. is discussed.The area involved includes sixteen 1:250,000 standard military sheets and covers approximately 96,000 sq. miles.The geology of the Willyama Complex is not dealt with but a small area of metasediments previously included in this unit is separated and a possible correlation with Precambrian to the east is suggested. Torrowangee Group sediments are described and the problem of nomenclature using a glacial implication is raised.Nine areas of proven Lower Palaeozoic sediments are considered and their relationship to the boundaries of the Bancannia Trough outlined. It is possible that some exposures not yet substantiated by fossil evidence may prove to be Lower Palaeozoic rather than Precambrian in age.The sediments of the Lachlan Geosyncline in the area of the Cobar massif are described and new concepts on the age and distribution of some of the established stratigraphic units are introduced. The absence of rocks of Middle Silurian age probably indicates the time of a major orogeny in this area.Lithology, thickness, and distribution of the Upper Devonian sediments is considered and some of the more recently found fish plate localities are listed.Mesozoic sediments occur in isolated areas of Lower Jurassic age and in the Great Australian (Artesian) Basin. A four-fold subdivision of sediments of the basin has been possible in some areas but lack of sub-surface information at present, precludes the possibility of correlation with the type sections in Queensland.Units in the Cainozoic are subdivided and a five fold subdivision of the Quaternary, at present being used throughout western New South Wales, is described.

Jan 1, 1969

The chief use of manganese ore is in the production of ferromanganese alloys for steelmaking. Manganese ores generally occur in tropical areas, which influences the type of treatment required. Present methods of treatment are relatively unsophist- icated but demands by customers for tighter specifications will necessitate the installation of gravity concentrator at many mines At present only limited tonnages of minus j in. product can be sold hence future development will centre around methods of producing an agglomerate satisfactory to the smelter.

Jan 1, 1969

By H. A. McKinstry, F. F. Lange

A vector analysis of orientating single crystals using the Laue back-reflection X-ray technique is given. Briefly, the analysis involves using a few data taken from a Laue photography and defining the crystal co- ordinate axes in a reference coordinate system. After a few matrix multiplications, the proper goniometer angles can then be determined to orient the crystal coincident with the reference frame. This analysis is easily programed for a digital computer to provide a fast, precise, and efficient method of orienting many crystals which are identical. The general procedure is as follows. The crystal is mounted on a goniometer. Laue photographs are taken until an array of diffraction spots is observed that includes a Laue spot that represents a rotational axis of symmetry. The rotation angles of goniometer are recorded. These angles are defined as positive for a counterclockwise rotation. When the axis of symmetry is located on the Laue photograph, the crystal coordinate axes can be defined in the reference coordinate system* as follows. Two Laue spots are chosen, one of which corresponds to the rotational axis of symmetry and the other to a set of planes whose zone axis is a known crystallographic direction and normal to the rotation axis of symmetry. The Laue spots are used to determine these two crystal directions in the reference coordinate frame. This is done by placing the Laue photograph on a sheet of polar coordinate graph paper and determining the polar coordinates (r, o) of these two diffraction spots in the reference coordinate frame. Their third coordinate is the distance between the crystal and the film (-D). The coordinates Xni of the two crystal directions Nn, (n = 1, 2) in the reference frame are then calculated by the following equations: Xn1 = -D X2n = Ancos on X3n = A, sin on where -tan- 1 rn/D An =Dtan(tan-1rp/D/2) By taking the proper cross products of these two directions (normalized to unit vectors), the crystal coordinate axes 3 (i = 1, 2, 3) can be determined in the reference frame. This is illustrated in Fig. 1. The next step is to determine the relation between

Jan 1, 1969

By O. F. Walker, W. C. Hahn, V. A. Johnson, J. D. Wood

The diffusion coefficients of zinc in single-crystal zinc and carbon in single-crystal and poly crystalline nickel were measured by means of radioactive tracer techniques both with and without the application of ultrasonic vibrations under conditions such that the temperature of the sample was closely controlled. The results of this investigation indicate no enhancement of diffusion in any of the samples. It is suggested that previously reported enhancement may have been due either solely to temperature increases caused by ultrasonic vibrations or in combination with changes in the boundary conditions. A number of observations have been reported in the literature in which it has been implied or inferred that the application of ultrasonics enhances diffusion (see, for example, Refs. 1-5). The present study was undertaken in an attempt to observe this effect under carefully controlled conditions, particularly with regard to measurement and control of the temperature of the sample. Two different types of systems were studied; these were the self-diffusion of zinc and the diffusion of carbon in nickel. EXPERIMENTAL For diffusion with ultrasonic energy applied, the samples were included as part of a resonant ultrasonic system operating at 58.5 kcps. The ultrasonic generators used were rated at 100 and 250 w and could be tuned over a frequency from 10 to 100 kc. A PZT (lead titanate/lead zirconate) ceramic transducer provided the driving vibration. This system requires no metallurgical joining of the specimen to the acoustical transmission line since the ultrasonic driver and the follow-up section clamp the specimen in position by means of a constant pressure of 50 lb developed by an air cylinder. The ultrasonic driver and follow-up section, both made of titanium, were 4 in. in length from clamping point to the end in contact with the specimen. Using the relationship given by Mason,6 A = V/f, the resonant wavelength, A, in titanium is calculated to be 3.3 in. at a frequency, f, of 58.5 kc, taking the velocity of sound in titanium, V, as 1.95 X 105 in. per sec. The 4-in. driver and follow-up section, therefore, are each 4.0/3.3 =1.21 times the resonant wavelength. Clamping pressure must be applied at stress nodes of the transmission line in order to preserve resonance. Therefore, a specimen length of 0.58 times the wavelength in the specimen was required to place the clamping pressure application points at stress nodes exactly three wavelengths apart. A stress antinode was contained in the center 3 in. of the specimen. A small PZT ceramic disc attached to the follow-up section provided an output voltage proportional to the intensity of the standing wave. This output voltage was monitored on an oscilloscope and the ultrasonic system was tuned to resonance by varying the frequency until the output signal was a maximum amplitude. The amplitude of the output signal was maintained constant throughout the diffusion anneal. A split cylindrical stainless-steel chamber, which was purged with argon prior to and during the runs, was placed around the specimen. The chamber in turn was surrounded by a movable furnace whose temperature could be controlled to 7C. Heat exchangers were used to cool the driver, follow-up section, and ultrasonic transducer. Great care was taken to obtain the true specimen temperature in all cases. Several different methods were tried; the most successful was that in which the thermocouple was held in contact with the midlength of the specimen by means of an asbestos insulating pad and wire straps. In the case of zinc, single-crystal specimens of 99.999 pct purity were used. The samples were 0.25 by 0.25 in. square and of the proper length for resonance, that is 1.1 in. long with the c axis parallel to the long dimension of the specimen for the case of diffusion perpendicular to the c axis and ultrasonic motion parallel to the c axis, and 1.9 in. long with the c axis perpendicular to the long dimension of the specimen for the case of diffusion parallel to the c axis and ultrasonic motion perpendicular to the c axis. In each case, one of the rectangular faces was electroplated with a thin film of zinc containing Zn The constant pressure used to clamp the specimen in place in the ultrasonic system caused some deformation in some of the samples. For these samples the deformation was concentrated in either end of the specimen; thus, for all samples (both zinc and nickel) the center in. was cut from the specimen after the diffusion anneal to be used for sectioning and counting. The nickel single-crystal samples, of 99.999 pct purity, were used in the form of rods 0.25 by 0.187 by 2.07 in. long with the (100) direction parallel to the rod axis. The polycrystalline nickel samples of 99.97 pct purity had an average grain diameter of 0.007 in. and were used in the form of rods 0.25 by 0.125 by 1.87 in. long. The direction of ultrasonic motion was parallel to (100) direction (bar axis) for the single-cqstal samples and parallel to the bar axis for the polycrystalline specimens. A thin film of c14 suspended in methanol was applied to the diffusing face of the specimen. Two specimens were butted together lengthwise for each diffusion anneal to minimize oxidation. After diffusion, a precision lapping device similar to the one described by Goldstein7 and a radiation detector were used to obtain a plot of specific activity vs penetration distance for each specimen. (A scintil-

Jan 1, 1969