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By B. L. Averbach, M. F. Comerford, M. B. Rough

The volume fraction of ß phase was determined in a Ti-6Al-4V alloy by measurements of integrated diffraction intensities. The (0002), and (100)ß diffraction lines were chosen because this combination minimizes the errors resulting from preferred orientation. The difficulties arising from fluorescence radiation were eliminated by use of a diffracted beam monochromator. A specimen quenched from 1475OF (800°C) contained approximately 5 pct ß, but in specimens quenched from higher temperatures no ß was found. The ß phase formed during aging, and in specimens solution treated at 1570oF (855oC) approximately 10 pct ß was present after aging at 1000°F (540°C) for 24 hr. This ß appears to form by decomposition of martensitic a'. ThE kinetics of the reactions which occur during the heat treatment of titanium alloys are complex ' and not completely understood. It has been proposed that hardening occurs in some alloys' on aging by the precipitation of a transition phase w followed by the formation of the stable a and ß phases. It has been proposed for other alloys2 that the a' marten-site decomposes by precipitating finely dispersed a particles. Most investigations have been hampered by the difficulties of determining quantitatively the amounts of the various phases present. This paper is concerned with the measurement of the amount of ß phase by an X-ray method, similar to one developed for the determination of retained austenite. The principal new feature was the use of a mono-chromator in the diffracted beam in order to reduce the fluorescence arising from the sample. EXPERIMENTAL PROCEDURE The experiments were carried out on an alloy of nominal composition Ti-6Al-4V (actual weight percentages: 6.2 Al, 4.1 V, 0.02 Mn, 0.17 Fe, 0.005 H, 0.03 C, and 0.02 N). The material was received as 5/8-in.-diam centerless ground rods in the annealed condition. The heat treatments were carried out in a vacuum of approximately 0.03µHg. The X-ray intensity measurements were made on 3/8-in. thick discs. The surface was prepared by grinding off about 0.060 in. and electropolishing in a solution af 60 ml (70 to 72 pct) perchloric acid in 1000 ml glacial acetic acid with a current density of 0.5 amp per sq cm.q The X-ray determination is based on the proportionality of the diffracted intensity of each line to the volume fraction of the corresponding phase. In calculating the intensities for a powder sample it is assumed that a large number of grains con- tributes to the diffracted intensity and that the grains are oriented at random. The presence of preferred orientation introduces serious errors in the relative intensities. The material used in this investigation exhibited a strong preferred orientation, which could not be removed by heat treatment. Other investigators have also found that preferred orientation may be retained after phase transformations. Glen and pugh5 performed a detailed analysis of the randomness expected after several allotropic transformations, but stated that this is not observed. Burgers,6 and Burgers and Ploos van Amstel,7 found that, in zirconium, the original orientation is retained after two phase transformations. Newkirk and Geisler8 observed similar behavior in titanium. On the basis of this evidence, it appears that, in the absence of plastic deformation, textures present in annealed titanium alloys are retained. Heating an a-ß alloy to the all-ß region and subsequent cooling to room temperature do not make the orientation of the mar-tensite different from that of the original a phase. In the present investigation it was possible to take advantage of the crystallographic relationships involved in the martensitic transformation to minimize the errors associated with preferred orientation. The relative orientation for titaniu-m marten-site9 takes the form (0001), 11 (110)ß; [1120], 11 [lll]ß. The same relationship has been proposed for zirconium' and certain titanium-base alloys.10-12 Additional sets of approximately parallel planes have been determined for titanium-nickel alloys." The influence of preferred orientation can be minimized by comparing intensities from parallel planes in the two related phases. If it is assumed that each family of planes in a given phase is equally well populated, the effect of preferred orientation can be eliminated by using the normal multiplicity for the family of planes since each set of parallel planes is equally preferred for any orientation of the sample relative to the X-ray beam. The most suitable combination of reflections in the Ti-6A1-4V alloy appeared to be (0002), and (110)ß It must be recognized that the ß formed during aging of the Ti-6A1-4V alloy is a precipitate rather

Jan 1, 1960

By D. E. Stephenson. Discussion by R. G. K. Morrison, L. Obert

R. G. K. Morrison (Chairman, Dept. of Mining Engineering and Applied Geophysics, McGill University, Montreal, Que., Canada) - The discing of drill core has been a recognized pressure phenomenon for many years but only recently has an interest been taken in the mechanism involved. The work of Jaeger and Cook is referred to in the text. The authors have now advanced the study to establish, within certain loading limitations, a direct relationship between axial and radial stress at failure. This is an important contribution. In mines generally, where pressure conditions result in the spalling of openings, the faces of drifts and crosscuts, on scaling, usually show a concavity with respect to the opening very similar to the face of the drill hole after the separation of the stub. The same holds for shaft sinks. This suggests a similarity between the mechanism of the discing of core and that of the spalling of an opening, under pressure, to develop a more stable outline. The latter, commonly regarded as shear, is the most conspicuous type of failure observed in

Jan 1, 1967

By AIME AIME

ABOUT one hundred were in attendance when Donald M. Liddell opened the session* on non-ferrous metallurgy at 2 p. m. on Tuesday. F. F. Col- cord was vice-chairman. For the first part of the session the chair was turned over to Frank G. Breyer, who introduced G. L. Spencer, Jr., to read his contribution (T.P. 378), "High Silica Retorts at the Rose Lake Smelter," which was an account of the method of manufacture of high-silica zinc retorts at the Rose Lake smelter, and of the service given by these retorts. The materials used are, by volume, 50 per cent clay, 25 per cent silica flour and 25 per cent grog. Written discussion of the paper by E. M. Johnson, W. R. In- galls and M. M. Neale was read by Mr. Breyer. Mr. Johnson explained that their practice in manufacture differed very little from Rose Lake practice, but that their retorts did not last as long, possibly because Eagle-Picher does not use a hydraulic retort press or sintered ore. He ascribes the longer life of silica re- torts to the fact that they do not bend under heat. Mr. Ingalls pointed out that silica retorts are no better as heat conductors than clay retorts, but that they do have a superior rigidity in the furnace. The character of the retorts does not affect the density of the charge. Mr. Neale gave the procedure in the manufacture and use of high-silica retorts at the Donora zinc works, not

Jan 1, 1931

By R. R. Morral, F. M. Krill, K. T. Aust

THE occurrence of twins in aluminum ingots cast under certain conditions has been well established. For instance, Herenguel and Lacombe1,2 have observed a twinned columnar structure in 99.5 and 99.9 pct Al, solidified by continuous or semicontinuous casting. The structure, which they termed "basaltic," appears in the form of elongated crystalline fibers of alternating luster. Herenguel and Lacombe2 found sections of flat crystalline plates composed of twin crystal plates, in which the twin plane (111) and a [I121 direction contained in the twin plane are parallel to the principal heat gradient. This orientation relationship is different from the usual orientation texture observed in cast face-centered cubic metals, where the [100] direction is approximately parallel to the long columnar axes lying in the direction of growth." A large amount of twinning has also been observed by the present authors in semicontinuous cast aluminum of 99.2 pct purity, Fig. 1. Mondolfo4 has suggested that the twinned cast structure forms by a deformation twinning process as the result of uneven cooling stresses within the ingots. This suggestion appears to be inconsistent with the large amount of twinning observed in the semicontinuous cast ingots and with the large difference of dendritic

Jan 1, 1953

By Stanley J. Gasior, Albert J. Forney, Joseph H. Field

Most bituminous coal mined near Eastern industrial areas requiring high-Btu pipeline gas is caking and therefore unsuitable for fixed-bed pres- sure gasification by present techniques. If the caking property of such coal can be destroyed, the resulting fuel can be gasified in a fixed bed at pressure with steam and oxygen as a preliminary step in making a high-Btu gas. To find a practical way to convert strongly caking coals of granular or small lump size to noncaking fuel was the object of this study. In previous work, strongly caking coals of 1/8- to 1½ -in. size were converted to a noncaking coal char by treatment in a static bed in about 3 hours1 and coal of 18-100 Tyler mesh in a fluidized bed in about 5 min.2 An inert gas such as steam, nitrogen, carbon dioxide or a mixture of all three with a small amount of oxygen was used in both studies. In our work a strongly caking bituminous coal from the Pittsburgh seam of 4-8 Tyler mesh size was converted to a noncaking form in free-fall in about 2 sec by dropping it through a countercurrent flow of steam containing 4% to 7% oxygen at 1150º-1200°F and 300 psig. This method should also be applicable to smaller-sized material.

Jan 3, 1965

By J. D. Mooney

(San Francisco sleeting, September, 1915) THE accompanying chart has been drawn for the convenience of engineers as a means of quickly determining the correct number of plies of conveyor belts operating under specific conditions. The calculations are based on the average safe strength (factor of safety, 15) of the various standard rubber conveyor belts. The, calculations assume maximum loading conditions; that is, the belt is considered as carrying the greatest load that it will handle without spillage at ordinary belt speeds. This not only produces the most economical operating conditions, but also the maximum tension in the belt. The chart is a graphical representation of the formula: p = kgW (L + 1OH) Where, p = the correct number of plies k = a constant, depending on the type of drive g = the weight in pounds per cubic foot of material handled W = the width of the belt in inches L = the length of the belt in feet (approximately twice the center distance). H = the difference in elevation between the head and tail pulleys, in feet. For a simple drive, with a bare pulley, k = 1/250,000 For a simple drive, with a rubber-lagged pulley, k = 1/300,000 For a tandem dive, with bare pulleys, k= 1/375,000 For a tandem drive, with rubber-lagged pulleys, k = 1/455,000 The chart is drawn for a simple drive, with a bare pulley (k =1/250,000;

Jan 9, 1915

Jan 1, 1969

By K. P. Mukherjee, K. P. Gupta, J. Bandyopadhyaya

Even though a lot of work has been done in the past to establish phase equilibrium in the Cu-Si system a re cent investigation casts some doubt about the existence and crystal structure of some of the phases that form in the composition range of 15 to 25 at. pct Si in Cu. The present investigation was carried out using high temperature X-ray diffraction technique along with other standard techniques to study the phases in this composition range. The high temperature 6 phase appears to be tetragonal with parameters a,, = 8.815A, c, = 7.903A, and co/ao = 0.896. The reported bcc E phase exists at room temperature and at least up to 780°C and appears to undergo a transformation near 600°C. The phase appears to be cubic but not of the bcc type. The ? phase appears to undergo a transformation, as has been indicated by earlier investigators, and the low temperature form of .? phase is tetragonal with parameters a, = 7.267A, co = 7.8924, and co/ao = 1.086. THE Cu-Si binary system has been investigated by several investigators1" and several intermediate phases,?,e,?' at lower temperatures and ?,ß,0,e, and ? at higher temperatures, were observed between terminal solid solutions of copper and silicon. Even though the existence of the e phase and the transformation in the ? phase were reported in many early works, in a recent study of this system Nowotny and Bittner6 doubted the existence of the e phase and phase at 550°C. Among the high temperature phases, the 6 phase was reported to have a complex cubic structure with parameter a, = 8.805A.7 Nowotny and Bittner, however, suggested that the structure of the 6 phase might be of CsCl type. In order to check these contradictory reports the present study was taken up to investigate the Cu-Si binary system in the composition range of 17 to 25 at. pct Si. EXPERIMENTAL PROCEDURE Weighed amounts of copper (99.99 pct) and silicon (99.9 pct) were induction melted in recrystallized alumina crucibles under argon gas atmosphere. The alloys containing 17, 18, 20, 21, 21.2, 22, and 24 at. pct Si were annealed in evacuated and sealed quartz capsules at 700°C for 3 days and subsequently water quenched. Other than this annealing, the 21.2 at. pct Si and 24 at. pct Si alloys were annealed at 550°C for 10 days, the 17 at. pct Si alloy was annealed at 750°C for 3 days, and the 22 and 24 at. pct Si alloys were annealed at 780°C for 2 days. All annealing temperatures were controlled to within *l°C. Alloys after quenching were subjected to metallographic and X-ray diffraction investigation. A solution containing 5 g FeC13 + 10 cc HCl + 120 cc H2O diluted with six times its volume with water was used as etching reagent. A 114.6 mm diam Debye Scherrer camera was used for obtaining diffraction patterns. The 17, 21.2, and 24 at. pct Si alloys were subjected to high temperature diffractometry using a Tempress Research High temperature attachment and a GEXRD VI diffractometer. For the 6 phase (17 at. pct Si alloy) powder specimen from a 750°C annealed alloy was reheated to 750°C in the high temperature attachment for 1½ hr before taking a diffraction trace. A 550°C annealed and slowly cooled phase (24 at. pct Si) alloy was first reheated to 550°C. a diffraction trace was made after annealing it for 2 hr, and subsequently it was heated to 716OC and kept at this temperature for 2 hr before taking a diffraction trace. For the e phase (21.2 at. pct Si alloy) a 550°C annealed and slowly cooled specimen was heated first to 425°C and annealed at this temperature for 2 hr before taking a diffraction trace. Subsequently, the specimen temperature was raised to 495", 540°, 603", 635", 682", 720°, and 748°C and homogenized at each temperature for 1 hr before taking diffraction traces. The powder specimen temperature was controlled to within +2oC at each temperature and argon gas, purified by passing it at slow rate through a fused CaC12 column, hot (800°C) copper and titanium chips and finally through a P2O5 column, was used to prevent oxidation of the powder. For all X-ray work copper-radiations at 25 kv, 15 ma (for Debye Scherrer technique), and 40 kv, 20 ma (for diffractometer tech-nique) were used. RESULTS AND DISCUSSION At 700°C the alloys containing 17 to 21 at. pct Si showed two phases while the 21.2 at. pct Si alloy was found to be single phase. The X-ray diffraction patterns of the two-phase alloys were consistent with the phase (ßP-Mn type structure) and the phase (21.2 at. pct Si) patterns. The diffraction patterns of the 17 at. pct Si alloy quenched from 750" and 700°C were identical. According to the accepted Cu-Si phase dia-gram4,5,10 the 17 at. pct Si alloy at 750°C should be in the (k + 6) two-phase region and very close to the -phase boundary. The identical patterns possibly resulted from the decomposition of the 6 phase on

Jan 1, 1970

By H. C. Chao, L. H. Van Vlack

Small MnS inclusions with known crystallographic orientations were placed inside powder compacts of low-carbon steel. After the metal was axially campressed with negligible end friction, the deformstions for the metal and the inclusions were compared. The MnS inclusions deformed more when the [100] direction was aligned with the compression axis than when the [111] direction was parallel to this axis. The deformations of the inclusions in the two principal radial directions were equal for each of the above orientations. Inclusions with [110] compression alignments did not deform with radial symmetry. The relative deformation of the inclusion and metal was closely dependent upon the relatiue hardness of the two phases. The relative deformation of the two phases was not sensitive to the rate of deformation. RECENT studies by the authors1.&apos; suggested that the plastic deformation of MnS in steel would probably be highly sensitive to the orientation of the inclusions and to the temperature of the metal. This paper reports an investigation of these factors upon MnS behavior within steel. Manganese sulfide (MnS) possesses an NaCl-type structure and typically has extensive (l10) {110} slip as a separate (noninclusion) crystal.&apos; A secondary slip system, ( l 10) { l l l}, has also been observed where the major slip system is restricted. In general, MnS inclusions must be rated as a highly deformable second phase.3 The amount of sulfide deformation varies, however, with several composition and processing factors. Some of these have been only partially assigned. For example, it is known that minor amounts (<0.01 pct) of silicon within free-machining steels will increase the amount of MnS deformation,4 but the mechanism of the added deformation can only be surmised at the present. Manganese sulfide and steel have sufficiently comparable deformation characteristics so that slip which is started in steel may be continued through the sulfide inclusions and back into the steel if the crystal orientations are favorable.5 A more detailed discussion of previous work on the plastic deformation of NaC1-type crystals and on the plastic deformation of inclusions within a metal is given in Chao&apos;s work.6 EXPERIMENTAL PROCEDURE The manganese sulfide which was used in this study was prepared by previously described methods.&apos; Single crystals of MnS, both as cleavage cubes and as spheres, were oriented within steel powder compacts so that the desired crystal directions were parallel to the direction of axial compression. A four-stage hydrostatic compaction procedure was used and involved the following steps. In the first stage part of the powder was placed in a metal die 1 in. in diameter with a thick (1 in. OD, 5/8 in. ID) rubber liner which had one end plugged. The steel powder was hand-rammed, making it as dense as possible before placing a carefully sized MnS crystal (either as a sphere or as a cube) near the center. The crystal was oriented with the chosen direction vertical; viz., [001], [011], or [111], with the aid of a X10 microscope. A pair of tungsten wire threads 0.020 in. in diameter was inserted along the side of this (&apos;core compact" to locate the desired plane after the compression tests. After the crystal was positioned in the center of the die, more powder was added and carefully rammed by hand. The die was then capped with a rubber plug of the same hardness and thickness as that of the liner. The whole assembly as shown in Fig. 1 was compacted by a ram load of 54,000 lb (about 70,000 psi). In the second stage a smaller, 3/4-in, rubber-lined die was used to give a stress of approximately 120,000 psi. The above process was repeated with the initial compact serving as a core for a larger compact. The final product after sintering was a cylinder 1 cm long and 1 cm in diameter, having a density of 7.54 g per cu cm. This was close to the theoretical density since the metal contained a non-metallic phase. There was no evidence of MnS deformation during the hydrostatic compaction or subsequent sintering. Elevated-temperature hardness data were obtained by procedures previously described.2 Compression tests for inclusion deformation utilized the cylinders which were described above. The critical problem in these tests was the lubri-

Jan 1, 1965

By Robert C. Edmiston

The measurement of temperatures in exploratory drill holes yields information on regional and local geothermal gradients and mean surface temperatures. This data may be beneficial to the mining geologist interested in the occurrence and oxidation of metallic sulfide minerals or to the mining engineer interested in subsurface temperatures or water movement. Additionally, the estimation of mean surface temperatures by the projection of thermal gradients to the ground surface provides data on which to evaluate infrared imagery as an exploration tool. Temperature measurements in 30 diamond drill holes in the Silver Bell mining district of Arizona show that a regional geothermal gradient of 2.45°C per 100 m increases to 3.03°C per 100 m near the ground surface. It is also found that an anomaly in the mean annual surface temperature of 0.5°C is associated with the shallow occurrence of disseminated sulfides. Changes in the geothermal gradient due to topography, water circulation, and formation changes also occur.

Jan 1, 1976

By E. J. KENNEDY

THE 142D MEETING of the Institute is rapidly shaping up with splendid prospects of a strong technical program and the lighter side of this annual occasion amply provided for. The date is February 20 to 23. The technical sessions will be held in the Engineering Societies building; the smoker-dinner, the informal dance, and the annual reception and dinner, at the Commodore Hotel, Monday, Tuesday and Wednesday respectively. The news to date on the technical side is as follows: Mining Methods-Subsidence The Mining Methods Committee has prepared an interesting program which will be divided into two sessions to be held early in the week. At the first there will be papers on mining methods and development, including a description of the "Sinking and Equipment of No. 2 Shaft at Minas de Matahambre," by Dudley D. Homer and R. H. Cromwell. They describe in considerable detail the equipment used and the practice followed in sinking this important shaft, giving detailed costs and performance figures. Hoist¬ing ?arrangements and mining practice at the "Red Ore Mines of the Woodward Iron Co. at Bessemer, Ala.," are described by Tenny C. DeSollar, superintendent of mines, in a second paper. At this session of the Mining Methods Committee, H. M. Roche and R. E. Crockett, of the Committee on Eastern Magnetite Mining and Milling Methods, will present their paper, "Iron Ore Mining at the Scrub Oak Mine." This mine is in the highlands of New Jersey about 40 miles west of New York City. Prof. Robert K. Warner of Yale University will present a paper on "The Selection of a Mining System," which should have an interesting discussion. Pierre R. Hines, of Portland, Ore., will present, with stereopticon slides, his paper on "The Owyhee Tunnels, U. S. Reclamation Project, Owyhee, Oregon," describing one of the recent irrigation undertakings.

Jan 1, 1933

By W. H. Moore, E. T. Powell

IN the early days of mining in the Anthracite field, only the thicker and better seams of coal were mined, because of the limited mining and coal-cleaning facilities, therefore many of the thinner and less productive seams were permitted to remain unmined. With improvements in mining methods, the introduction of modem preparation plants, and the increased market demand for small-size coal, the thinner and more laminated seams have now become assets. In many instances these seams overlie the mined-out beds of the thicker and better seams, from which all recoverable coal was removed by the conventional breast-and-pillar method of mining. Some collieries in certain sections of the Anthracite field are now relying on these thinner and laminated seams. For the purpose of illustration, a large area in the Hickory Swamp-Ridge Basin of the western middle coal field has been selected, where as early as 1898 the No. 4, or Little Buck Mountain, seam was mined and pillars removed. The No. 5, or Buck Mountain, seam lying on a comparatively light pitch and with intervening strata of but 55 ft. of rock was not mined until 1935. Farther east, in the same basin the Nos. 8 and 9 seams, which are two splits of the Mammoth seam, have been mined and robbed and the workings have been abandoned since 1896. The overlying No. 9 ¾ seam, or the upper split of the Mammoth, and the No. 9 ¾ or 4-ft. seam remained virgin, with only an interval of 50 ft. of rock separating them, and with 40 to 50 ft. of rock strata separating the No. 9 ½ seam from the completely mined area of the Nos. 8 and 9 seams. These seams lie on a pitch of 45° on the south side of the basin and on 75° on the north side of the basin. Mining has been carried on in the 9 ½ and 9 ¾ seams for 3 years on both dips of the basin, for a distance of 3500 ft. In some sections the overlying strata of the thicker seams previously mined have settled without any apparent breaks in the upper strata, as indications have shown in the top split of the Mammoth; while in other areas the roof and bottom of this top split of the Mammoth have settled unevenly, thereby causing the bottom and roof to break into blocks. In attempting to mine over a large area of the No. 5 or Buck Mountain seam, a similar settlement has been encountered; the roof of the seam has been broken and a considerable amount of timbering has been necessary in order to make the mining of the seam possible. The conventional breast-and-pillar method, using shaker conveyors, has been used in the No. 5 seam, and a slant-breast method in the mining of Nos. 9 ½ and 9 ¾ seams. MINING OF LIGHT-PITCH SEAMS The No. 4 seam was mined and robbed by the conventional breast-and-pillar system. In this area the seam pitched from 5° to 25° on the north dip, averaged 8 ft. in thickness and had a slate bottom and a

Jan 1, 1941

By H. J. Modi, D. W. Fuerstenau

pH effectively regulates the flotation of corundum through its control of the surface charge. Since collector ions function as counter ions in the double layer, the collector must be anionic when corundum is positively charged and cationic when it is negatively charged. Even a long-chained xanthate will float positively charged corundum. Association of the hydrocarbon chains of the adsorbed collector ions gives rise to increased adsorption and increased rate of flotation. Because of this phenomenon, neutral organic molecules aid flotation although the unionized collector cannot promote flotation independently. Na2SO4 was found to depress the flotation of corundum with animic collectors through ionic competition whereas the same salt activates corundum for flotation with cationic collectors. A close connection between ion association, electrokinetic behavior, and floatability is suggested. As part of the increasing interest in the physical chemistry of flotation, strong experimental evidence has been obtained which indicates that organic ions are adsorbed as counter ions by non-metallic oxide minerals mainly because of the electrical forces which exist at interfaces(1-3). Thus flotation of such minerals without activation should then be appreciable only when the mineral and the collector are oppositely charged. Since only limited work has been reported on the effect of surface charge upon flotation behavior(3) this general hypothesis on the flotation of insoluble oxide minerals has not been tested thoroughly. Investigating the flotation of a mineral for which extensive electrokinetic data exist yields a way to test this hypothesis more extensively. The electrokinetic behavior of corundum in solutions containing both organic and inorganic electrolytes has been studied quite thoroughly&apos; Electro-kinetic measurements have shown that in the case of corundum, simply by controlling pH the solid surface can be charged either positively or negatively. For this reason corundum was chosen for study. The object of this paper is to present a study of the flotation of corundum and to explain the results in the light of our knowledge of adsorption mechanisms gained from streaming potential investigations. This paper is concerned mainly with the effect of surface charge on flotation with anionic and cationic collectors, but in addition such flotation phenomena as collector hydrolysis, Van der Waals attraction between hydrocarbon chains, ionic competition, and activation are discussed. While the present paper is confined to a reporting of the data obtained and some of the more immediate conclusions, it will be seen that the results, in combination with those on other systems, do promise a

Jan 1, 1961

Jan 1, 1967

By W. G. Davenport, M. Paneni

Experiments in sheets of mercury and water have confirmed that the dynamics of bubble rise are simi-lur in Liquid metal and aqueous systems. RECOGNITION that bubble/metal interactions are important in pyrometallurgical refining processes (e.g., steelmaking, vacuum degassing, deoxidation of copper) has led to a number of investigations into the dynamic behavior of bubbles rising in liquid metals. Terminal velocities of bubbles rising in mercury (20°C)&apos; and silver (1000" to 1050"c)1,2 have been measured. Good agreement between aqueous and liquid metal systems has been obtained. Shapes of air bubbles rising in mercury have been determined experimentally by Davenport, Bradshaw, and Richardsonl who used a system of electric probes to measure maximum horizontal and vertical dimensions, Fig. 5. In the present work the motion and shape of nitrogen bubbles rising in a thin sheet of mercury (i.e., a "two-dimensional" environment) have been studied with the view of confirming dynamic similarity between aqueous and metallic systems. The use of thin sheets of liquid permitted direct visual and photographic comparisons of bubble behavior in clear liquids and in mercury. EXPERIMENTAL METHOD The thin sheets of mercury or water were held in a clear acrylic plastic container, Fig. 1. The sheets of liquid were 80 cm high by 30 cm wide and 0.47 cm thick. Single bubbles were formed by injecting the desired volume of nitrogen into an inverted semicircular cup (stainless steel). The cup was then rotated into the upright position using an external handle thus releasing a single bubble of measured volume. Nitrogen was injected into the cup from a nitrogen cylinder through the external handle and a hollow rotating axle. The volume of a bubble (volume range 0.01 to 10 cu cm) at any instant was obtained by connecting a soap film meter to a small gas space above the liquid. By this technique any change in the volume of a gas bubble in the liquid (i.e., during cup filling or during rise) produces an equivalent displacement from gas space A into the buret B. This displacement is determined by measuring the movement of a horizontal soap film in the buret. Bubble shapes were determined using single-frame photography. Rising velocities were determined by cinephotography with a 1/100-sec stopwatch in the field of view. In both cases dimensions were referenced to a rule attached to the container surface, also in the field of view. Linear dimensions were measured on projections of the single-frame negatives. Rising velocities were calculated from measured heights of rise (10 to 20 cm) and times of rise. The effects of disturbances caused by cup rotation and by bubble release were minimized by photographing bubbles at a point not less than 25 cm above the cup. MATERIALS Mercury: Technical-grade purified: minimum 99 pct Hg; Johnson Matthey and Mallory Limited, Toronto. Nitrogen: Technical-grade purified nitrogen: 99.99 pct Nz, 0.01 pct 02, trace argon; Air Liquide Canada Limitee, Montreal.

Jan 1, 1970

By D. A. Elgillani, M. C. Fuerstenau

With either sulfonate or oleate as collector, quartz responds to flotation with moderate additions of calcium only at moderately high pH, where some portion of the activator has hydrolyzed to caOH+ . Calculations of the concentrations of various ionic and precipitated species of calcium and collectors suggest that the products of [(CaOH+) (RSO3)] and [(CaOH+)(01-)] determine whether flotation is obtained under specific conditions. Ion products on the order of 10-12 were calculated for both the sulfonate and oleate systems. The activating effect of calcium ion in nonmetallic flotation systems is of considerable interest because of the normal presence of calcium in natural water. As a result, this phenomenon has received quite some attention in the past. Kraeber and Boppel1 showed that quartz could be activated by calcium above pH 10 with sulfonate as collector. The feasibility of selectively separating quartz from hematite with calcium activation at relatively high pH was demonstrated by Clemmer, Clemmons, Rampacek, Williams, and stacy.2 Cooke and Digre3 showed with a bubble pick-up method that the minimum quantity of calcium ion required as activator for complete pick-up of particles occurs at pH 11.5 for an addition of 20 mg per liter sodium oleate. They also showed that larger additions of calcium (10-fold increase per unit decrease of pH) must be added for complete bubble pick-up as the pH is reduced. Schuhmann and Prakash,4 using a vacuum flotation technique, found that quartz could be floated with moderate additions of calcium chloride and oleic acid at neutral pH, providing the metal ion was present in stoichiometric excess over the quantity needed to form the normal soap with oleic acid. They also reported that calcium will function as an activator only in basic media. More recently, Eigeles and volova5 have shown that essentially complete flotation of quartz is obtained with 6 x 10-4 mole per liter calcium chloride and 1.7 x 10-5 mole per liter sodium oleate at pH 11.6. while no flotation is obtained at about pH 10.9 and below. The importance of adsorption of activator and collector at the air-liquid interface is also demonstrated in these systems. The important role that metal ion hydrolysis assumes in quartz activation systems was also demonstrated recently.6-8 A detailed investigation of metal activation in sulfonate flotation of quartz was undertaken in one system7 and yielded a number of interesting and important observations. Quantification of the data of this system7 to the extent desired was not possible, though, because certain species could neither be ignored nor accounted for accurately. These difficulties can be circumvented when calcium is involved as activator. This detailed analysis was undertaken to obtain a more quantitative explanation of calcium and metal ion activation in quartz flotation. EXPERIMENTAL MATERIALS AND METHODS Sodium alkyl aryl sulfonate9 mol wt 450, and pure potassium oleate were used as collectors. All other reagents used were reagent grade in quality, i.e., n-amyl alcohol as frother, KOH for pH adjustment, and calcium chloride. Conductivity water, made by passing distilled water through an ion exchange column, was used in the investigation. Quartz was prepared by leaching the sized sample (48 x 150 mesh) with HC1 until no iron could be detected in the leach liquor. The experimental equipment and procedure were the same as that described previously.6,10 EXPERIMENTAL RESULTS As the presence of precipitates was noted in all of the systems to which ca++ and collector were added, experiments were undertaken to determine the solubility products of calcium sulfonate and calcium oleate using a nephelometer. With this technique, collector is titrated into a known solution, which in this case was 5 x 10-5 mole per liter CaCl2 at pH 5.5. Upon precipitation of the calcium-col lector salt, e.g., calcium oleate, light is scattered and detected

Jan 1, 1967

By T. R. Braithwaite

The brief comments made in this chapter deal mainly with shaft sinking, but don&apos;t assume that freezing techniques apply only to shaft sinking. They can be used on tunnel work, on such things as liquid gas storage in sediment, and I think you will probably see other applications for it as we go along. The method was first developed in 1883 and was used to sink shallow shafts through water-bearing overburden in Germany and in England. One of the early shafts was in Germany and was sunk by freezing to 310-ft depth. The project required 17 months for drilling, roughly 5 1/2 months for freezing, and another 7 months for sinking, giving an average progress of 10 ½ fpm. Fortunately there have been numerous improvements and new developments in this technique through the years. With equipment and techniques available today, we can take a 20-ft-diam shaft down through 2000 ft of water-saturated overburden and the time schedule runs roughly 4 months for site preparation, freeze-hole drilling, installing the casings, and setting up the plant; 4 ½ months for freezing; and 6 months for excavating and installing permanent linings. This gives a progress rate of about 140 fpm, on average. I might qualify that a little in that the special linings that are required for some formations can affect the time. If it&apos;s straightforward sinking where one can use a heavy concrete lining, up to 630-640 fpm may be achieved in a shaft; but with special cast-iron tubbing or types like that, 5 fpd is pretty good progress, so the lining does affect the time. The freezing method is used mainly for sinking shafts through unstable water-bearing formations which cannot be grouted either effectively or economically and which are too deep to enclose in pile casing. Even with overburden, grouting methods available today can handle roughly 100 lb water pressure; in the range of, say, 100 to 150 ft from the surface, it&apos;s very often best to grout 40 or 50 ft. You normally drive a pile casing and go through it. Below that range, freezing is very often the economical

Jan 1, 1970

President and Director JOSEPH L GILLSON, &apos;62 Wilmington, Del Past President and Director HOWARD C PYLE, &apos;61, Los Angeles, Calif President-elect and Director R R McNAUGHTON, &apos;63, Trail, B C, Canada

Jan 1, 1960

THE total crude production from the Dutch East Indies, and the British Protectorates of Sarawak and Brunei for 1932 is given in the following table: BARRELS BARRELS (42 GAL.) (42 GAL.) North Sumatra 4,226,935 Ceram 326,207 South Sumatra 13,956,157 Sarawak 2,739,650 Java 3,845,568 Brunei 1,322,725 Dutch Borneo (main island) . 9,406,733 Dutch Borneo (Island of Tara- kan) 6,579,184 Total 42,403,159 Production, which had shown a rapid increase from 1921 to 1929, has since been reduced. Exploitation drilling in the majority of the larger fields was suspended and existing production kept within predetermined limits by beaning. Most of the smaller fields were shut down entirely. The depth of producing levels varies widely in the different fields. Shallow fields with drilling depths to 500 meters (1650 ft.) are still numer-ous as well as those with depths between 500 and 1000 m. (3300 ft.). A few of the newer fields reach greater drilling depths. up to 1600 m. (5250 ft.). The deepest exploration well drilled to date (Djambi field, South Sumatra) reached a depth of 2332 m. (7650 ft.) before abandon-ment in March, 1930. The specific gravities of the various crude oils produced range between 0.65 (86.2° A.P.I.) and 0.95 (17.5° A.P.I.). The lighter crudes have a high gasoline content and fuel oils are derived from the heavier crudes, which usually are rich in paraffin.

Jan 1, 1933

By Lauren A. Wright, A. E. J. Engel

Under the designations "industrial talc" and "soapstone" are included earth materials of widely different chemical and mineral compositions. Talc, the mineral, is a hydrous magnesium silicate, with a suggested theoretical formula H2Mg3(SiO3)4 or H2O.3MgO.4SiO2, which postulates 63.5 pct SiO2, 31.7 pct MgO, and 4.8 pct H20.18 Single grains or leaves of talc, however, seem to have variations in water content that range from 3.5 pct to more than 7 pct, as well as slight differences in the proportions of MgO and Si02.20 Most of the industrial talcs produced in the United States do not approach the composition given above (see Table 1), but are essen- [ ]

Jan 1, 1960