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By T. E. Leontis

The importance of magnesium alloys in the manufacture of aircraft engines has been realized for many years. A concentrated effort has been exerted in the laboratories of the Dow Chemical Co. to develop magnesium-base alloys with improved properties at elevated temperatures whereby greater advantage can be taken of the inherent lightness of these materials. In an earlier publication, attention was called to the superior tensile properties and resistance to creep of cerium-containing magnesium alloys at temperatures up to 700°F. More recently, additional data on magnesium-cerium alloys have been furnished by Murphy and Payne. The present paper deals with the mechanical properties of sand-cast magnesium alloys containing zinc, at temperatures up to 500°F. The study includes binary Mg-Znt alloys containing up to 10 pct zinc and several ternary and some polynary alloys based on the Mg-~Zn,f Mg-jZn, Mg-4.4211, Mg-6Zn, and Mg-roZn binaries. The compositional variation in the tensile properties, hardness, and creep at room and elevated temperatures, and in the electrical conductivity at room temperature has been determined. The results of these tests show that many zinc-containing magnesium alloys exhibit resistance to creep at elevated temperatures significantly higher than that of present commercial magnesium alloys, but lower than that of alloys of the magnesium-cerium type. In addition, they have high tensile properties at room and elevated temperatures and high conductivity. This combination of mechanical properties and conductivity indicates that these alloys should be given serious consideration for commercial applications involving exposure to temperatures higher than those to which present commercial magnesium alloys can be taken safely. Literature The properties of sand-cast magnesium alloys containing zinc as a principal alloying element have not been investigated very extensively, especially at elevated temperatures. The following remarks, which are confined to sand-cast alloys, will serve as a summary of the most important references on this phase of magnesium metallurgy. The first recorded determination of the tensile strength of binary Mg-Zn alloys as a function of zinc content was reported by Aitchison. Similar studies, including the measurement of elongation and hardness, have been performed by Gann and Winston,' Dumas and Rockaert, Haugh-ton and Prytherch,6 and by Spitaler, the last being reported by Beck.' A slight superiority in the tensile strength of chill-cent Mg + 8 es alloy Over the sand-cast alloy was noted by Maybrey.8 That alloys of magnesium containing 5 to 12 pct zinc

Jan 1, 1949

By Herbert H. Kellogg, Hugo Vasquez- Rosas

Recently the long-chain primary amines have been used extensively for the flotation of silicate minerals. The use of amines to float sulphide minerals has been investigated by several authorsl-5-l8 but most of this work has been done with the short-chain (less than six carbon atoms) primary amine compounds or the more expensive secondary, tertiary and quaternary amines. Perhaps the fact that the long-chain amines are good collectors for the common gangue minerals has led investigators to omit them from consideration as collectors for the selective flotation of metallic sulphides. The work reported in this paper was designed to investigate the use of a typical long-chain amine salt, laurylamine hydro-chloride, as a collector for the flotation of galena-sphalerite ores. The results show that laurylamine hydrochloride (LAmHCl), when used in small amounts, is a good collector for the selective flotation of sphalerite and galena from the common gangue minerals. The differential flotation of sphalerite from galena was not accomplished but the amine flotation of sphalerite after the standard xanthate flotation of galena is possible. The experimental work reported herein is not complete enough to be able to say whether amine flotation of lead-zinc ores would prove superior to xanthate flotation, or whether the method is even applicable to a more complex ore than the one used for this work. However, the apparent reagent costs for the flotation operations described in this paper seem to be less than for xanthate flotation. This fact alone should be sufficient to encourage the millman to investigate the use of these amine reagents, especially as these reagents are available on a commercial scale at a reasonable price. This paper has as its secondary purposes to illustrate how contact-angle measurements have aided in this investigation, and to bring forward some evidence concerning the mechanism of the collecting action of primary amines. Contact-angle Tests The contact-angle measurements were made by the method described by del Giudice6 and used in recent work by Taggart and his collaborators.7-9 The mineral specimens for the contact-angle tests were carefully chosen, to avoid cracks and inclusions of other minerals. All specimens were mounted in "transoptic" plastic mounts and the surfaces were cleaned by polishing with levigated alumina on a cloth-coverkd glass polishing wheel. Distilled water was used on the lap during the polishing and at all subsequent steps in the contact-angle tests. The mounted mineral specimens were handled with glass forceps and special care was exercised to prevent exposure of the clean surface to air or any other source of contamination.

Jan 1, 1947

By J. M. McKenzie

p-n junctions to detect and measure the energy of single quanta of electromagnetic radiation are described. Useful energy range is from 1 kev to several Meu. Achieved energy resolution varies from 30 pct at 6 keu to 0.12 pct at 2 Mev. Parameters affecting the perfornzance of the present detectors and desired of a new material are discussed. DURING the last 6 years semiconductor detectors have been used extensively to detect and to measure the energy of charged particles. These detectors are made from reverse-biased p-n junctions. Electron-hole pairs are created in the depletion region of the junction, Fig. 1. The carriers are separated by the electric field and give rise to a pulse of current in the external circuit. This current pulse is proportional to the number of carriers and hence to the energy deposited in the depletion region by the ionizing event. More recently the discovery of the lithium drift process, first in silicon' and then in germanium,2 has extended the use of semiconductor detectors to the detection and the energy measurement of single quanta of electromagnetic radiation. These detectors now have a useful measurement range extending from the soft X-ray region, about 6 kev, to the hard y ray region of several Mev. Surface-contoured avalanche diodes can be used to extend this range down to 1 kev. There is however a desire for other materials suited to higher operating temperatures, and particularly for those materials with high y ray stopping power. The most important advantage of the semiconductor detector over gaseous and scintillation detectors is the average energy, E, required to form an electron-hole pair. Fig. 2 shows the quantum efficiency for germanium as a function of photon energy.3 At the band-gap energy, 0.7 ev, an electron-hole pair is generated by the absorption of the photon and the quantum efficiency is unity. The quantum efficiency remains constant at unity between 0.7 and 3 ev. It then increases as additional electron-hole pairs are formed by secondary ionization of the initial photoelectron. The rate of increase is about 1 electron-hole pair per 3 ev (actually 2.9 ev for germanium and 3.6 ev for silicon). This figure is constant irrespective of the particle type (electron, proton, a particle, heavy ion) and energy. In an ionizing event an incident particle of energy E will create N = E/e ion pairs. The statistical fluctuation in this number is proportional to &. The fractional energy resolution is therefore proportional

Jan 1, 1968

By Herbert H. Kellogg, Hugo Vasquez- Rosas

Recently the long-chain primary amines have been used extensively for the flotation of silicate minerals. The use of amines to float sulphide minerals has been investigated by several authorsl-5-l8 but most of this work has been done with the short-chain (less than six carbon atoms) primary amine compounds or the more expensive secondary, tertiary and quaternary amines. Perhaps the fact that the long-chain amines are good collectors for the common gangue minerals has led investigators to omit them from consideration as collectors for the selective flotation of metallic sulphides. The work reported in this paper was designed to investigate the use of a typical long-chain amine salt, laurylamine hydro-chloride, as a collector for the flotation of galena-sphalerite ores. The results show that laurylamine hydrochloride (LAmHCl), when used in small amounts, is a good collector for the selective flotation of sphalerite and galena from the common gangue minerals. The differential flotation of sphalerite from galena was not accomplished but the amine flotation of sphalerite after the standard xanthate flotation of galena is possible. The experimental work reported herein is not complete enough to be able to say whether amine flotation of lead-zinc ores would prove superior to xanthate flotation, or whether the method is even applicable to a more complex ore than the one used for this work. However, the apparent reagent costs for the flotation operations described in this paper seem to be less than for xanthate flotation. This fact alone should be sufficient to encourage the millman to investigate the use of these amine reagents, especially as these reagents are available on a commercial scale at a reasonable price. This paper has as its secondary purposes to illustrate how contact-angle measurements have aided in this investigation, and to bring forward some evidence concerning the mechanism of the collecting action of primary amines. Contact-angle Tests The contact-angle measurements were made by the method described by del Giudice6 and used in recent work by Taggart and his collaborators.7-9 The mineral specimens for the contact-angle tests were carefully chosen, to avoid cracks and inclusions of other minerals. All specimens were mounted in "transoptic" plastic mounts and the surfaces were cleaned by polishing with levigated alumina on a cloth-coverkd glass polishing wheel. Distilled water was used on the lap during the polishing and at all subsequent steps in the contact-angle tests. The mounted mineral specimens were handled with glass forceps and special care was exercised to prevent exposure of the clean surface to air or any other source of contamination.

Jan 1, 1947

By L. L. Handy

Two equations are compared for calculating imbibi-tion rates of water into porous media. A linear relation was found to apply when the square of the volume of water imbibed was plotted against time for water imbibing in natural rock materials. The effect of adsorbed organic materials on surface wettability was determined from measurements of rate of imbibition, water saturation and water permeability. INTRODUCTION An understanding of the mechanisms by which water displaces oil from porous media requires an understanding of the role of capillary forces in the displacement process. The capillary forces are determined by properties of the water-oil-solid surfaces. Consequently, some measure of the surface properties of reservoir rocks is necessary if displacement behavior in oil reservoirs is to be predicted from laboratory measurements. Several experimental procedures have been proposed to assign quantitative wettability indexes to reservoir rock surfaces. The most recent of these proposals are those of Bobek, Mattox and Denekas' and Amott.' These indexes are designed to show a continuous variation from the preferential oil-wet to the preferential water-wet systems. They require measuring some property of the rock which is a function of surface wettability. The quantities are measured on unaltered core material and compared with values obtained for known oil-wet and water-wet extremes on the same material. These methods are useful but are semi-empirical in nature. They have the disadvantage that the measured quantities may be functions of other variables in addition to surface wettability. Some understanding of the behavior of water-oil-rock systems may be obtained from studies of the simpler water-air-rock systems. Surfaces of a given wettability are more easily maintained for the latter. Also, certain approximations can be made for the flow of water and air which are not justified for water-oil flow. The theoretical and experimental work discussed in this paper is part of a study of the role of capillarity in the dynamic displacement of air by water. The expec- tation is that observations for the water-air system will lead to generalizations which are applicable to water-oil systems. THEORY Imbibition is defined as that process by which one fluid displaces another from a porous medium as a result of capillary forces only. Differential equations have been derived to describe the displacement of oil by water during imbibition, but these equations have not been solved.".' With certain assumptions, however, solutions are possible for water-air imbibition.

By Otto H. Henry, J. J. Cordiano

Though powder metallurgy is one of the oldest of metallurgical processes, it is in its infancy as a branch of the modern field of metallurgy. As early as 3000 B.C., the ancients produced implements and weapons of iron by reducing iron ore in a charcoal fire and forging the resultant sponge while still hot into the desired shape. Melting and casting soon superseded the powder metallurgy practice, and it was not until the turn of the twentieth century that powder metallurgy was applied to the commercial manufacture of tungsten lamp filaments. From this beginning, the use of the powder metallurgy process spread" to the manufacture of porous oil-impregnated bearings, cemented carbide tools, contact points, diamond grinding wheels, clutch facings, starter brushes, resin-bonded radio cores, magnets, metallic filters, and other parts. More recently, and particularly during the present war, there has been a definite trend toward the manufacture of machine parts by this process in competition with the more conventional fabricating methods. Notwithstanding these many developments, scientific progress has been slow. While many articles on powder metallurgy have appeared in the press and various publications, there have been too few contributions to our technical societies, with the result that there is a dearth of the type of information necessary for the full development of this science. It is of primary importance that the results of research and development be freely disseminated if powder metallurgy is to realize its fullest potentialities. Purpose of Investigation Excluding the refractory metal field, all commercial powder metallurgical products made by a cold compressing and sintering operation contain voids. These voids can be substantially eliminated by subsequent severe working and heat-treatment, but ' such practice has not proved economical in most applications. By applying heat during the compressing operation, plastic deformation of the powder particles is substantially increased, and the resultant compact or briquette is practically free of voids. However, hot-pressing has many attendant problems, which at present preclude its use in the manufacture of precision parts. The more important of these are to devise: 1. A die steel capable of withstanding high pressures at elevated temperatures. 2. A high-temperature lubricant capable of preventing excessive die wear and welding of the compact to the die walls. 3. A method of retaining a neutral or reducing atmosphere in the compacting zone of the die assembly. 4. A means of ejecting the hot-pressed specimen into a neutral atmosphere until reasonably cold.

Jan 1, 1946

By S. R. B. Cooke, S. W. Clark

Adsorption of calcium and magnesium by quartz was determined over a wide pH range using flame photometry for solution analysis. A parallelism was noted between calcium adsorption at alkaline pH and flotation of activated quartz by means of various fatty acid collectors. Abstraction of calcium from 100 ppm solutions increased above pH 10.5 until all of the calcium was removed at pH values between 12 and 12.5. Calcium was desorbed from the quartz over the pH range 12.5 to 13.0 and returned to the solution. Precipitation of magnesium hydroxide prevented measurement of magnesium adsorption above a pH of 9.9. A calcium adsorption isotherm determined at pH 9 matched measurements of barium adsorption by other investigators over the range where adsorption corresponded to the equation of a Freundlich adsorption isotherm. In accordance with the Gouy-Chapman theory for adsorption in the diffuse layer, adsorption of the divalent cations under these conditions was four times the adsorption of monovalent sodium. Activation of quartz by multivalent metal cations in flotation using anionic collectors has been studied by many investigators. The occurrence of activator cations in the water of flotation mills makes depression of silaceous gangue very difficult. Alternatively, in some flotation systems it is practical to cause activation of quartz so that it is floated from the desirable mineral values. The present study was initiated to investigate the activation of quartz by measuring adsorption of calcium and magnesium ions as a function of solution pH. Early empirical tests showed that quartz would be activated to flotation using anionic collectors if any of a number of divalent or trivalent metallic cations were present in the pulp.1*2 Subsequent studies by Clemmer,3 Cooke and Digre,4 Cooke,5 Schuhmann and Prakash,6 and Cooke, Iwasaki, and Choi,7-8 showed that flotation depended strongly upon the alkalinity of the flotation pulp, the concentration of the activating cations, and the chain length and structure of the organic collectors used. The concept of the electrical double layer has been applied to the case of the quartz-aqueous solution interface by Gaudin and Fuerstenau,9-10 and by de Bruyn 11 to explain the activation of quartz by multivalent metal cations. Studies of the surface of quartz by Gaudin and Fuerstenau9,10,12 and by Li " using the streaming potential technique contributed much information on the electro kinetic condition of the surface of quartz in the presence of various organic and inorganic ions. Measurement of adsorption of ac-

Jan 1, 1969

By Otto H. Henry, J. J. Cordiano

Though powder metallurgy is one of the oldest of metallurgical processes, it is in its infancy as a branch of the modern field of metallurgy. As early as 3000 B.C., the ancients produced implements and weapons of iron by reducing iron ore in a charcoal fire and forging the resultant sponge while still hot into the desired shape. Melting and casting soon superseded the powder metallurgy practice, and it was not until the turn of the twentieth century that powder metallurgy was applied to the commercial manufacture of tungsten lamp filaments. From this beginning, the use of the powder metallurgy process spread" to the manufacture of porous oil-impregnated bearings, cemented carbide tools, contact points, diamond grinding wheels, clutch facings, starter brushes, resin-bonded radio cores, magnets, metallic filters, and other parts. More recently, and particularly during the present war, there has been a definite trend toward the manufacture of machine parts by this process in competition with the more conventional fabricating methods. Notwithstanding these many developments, scientific progress has been slow. While many articles on powder metallurgy have appeared in the press and various publications, there have been too few contributions to our technical societies, with the result that there is a dearth of the type of information necessary for the full development of this science. It is of primary importance that the results of research and development be freely disseminated if powder metallurgy is to realize its fullest potentialities. Purpose of Investigation Excluding the refractory metal field, all commercial powder metallurgical products made by a cold compressing and sintering operation contain voids. These voids can be substantially eliminated by subsequent severe working and heat-treatment, but ' such practice has not proved economical in most applications. By applying heat during the compressing operation, plastic deformation of the powder particles is substantially increased, and the resultant compact or briquette is practically free of voids. However, hot-pressing has many attendant problems, which at present preclude its use in the manufacture of precision parts. The more important of these are to devise: 1. A die steel capable of withstanding high pressures at elevated temperatures. 2. A high-temperature lubricant capable of preventing excessive die wear and welding of the compact to the die walls. 3. A method of retaining a neutral or reducing atmosphere in the compacting zone of the die assembly. 4. A means of ejecting the hot-pressed specimen into a neutral atmosphere until reasonably cold.

Jan 1, 1946

By F. H. Wilson, R. M. Brick

With the papers of Palmer and Smith1 and of Burghoff and Bohlen,2 published in 1942, understanding of the problem of the development of ears on deep-drawn brass cups was brought to the point where, from a practical standpoint, producers of brass sheet could keep earing under control. However, these very practical results raised questions concerning the reasons for the observed behavior. Since plastic deformation is fundamentally a function of crystallographic slip, these reasons must be considered in the light of the textures to be found in the annealed sheet. Various attempts have been made. to interpret the mechanism of ear formation by correlation with the preferred orientation and the anisotropy of the sheet. However, none of these has satisfactorily explained why ears are usually found in the rolling and transverse directions for copper but at 45' to these directions for brass. This paper offers additional data on these two related subjects and has been divided into two sections The first section provides a survey of the recrystallization textures of brass as affected by annealing temperatures and prior reductions, and an account of the caring behavior which accompanies these textures. The second section reports new data on the anisotropy that accompanies a characteristic texture for brass and endeavors with partial success to establish the factors that account for the difference in earing behavior between copper and brass Earing BehavioR oF Brass Review of Textures The recrystallization texture of severely rolled brass was first reported by Bass and Glocker.3 The preferred orientation to which this texture, obtained from metal annealed at 500°C., was most akin was (II3)[I12] This texture has been confirmed by Bauer, von Göler and Sachs;4 Brick;' Brick, Martin and Angier;6 and Cook and Richards7 who, in general, used annealing temperatures under 500°C. Bass and Glocker3 also reported the recrystallization texture at 850°C. to be the same as at 500°C. They analyzed their textures by means of single photograms obtained with white radiation. The photo-grams for both temperatures are reproduced in their paper, and there is a strong similarity between the two. However, for the latter temperature, the number of spots registered on the film was remarkably large for the grain size to be expected, and the authors made no mention of using a technique that would integrate a large enough area of the specimen to produce so many spots. The only other attempt to determine textures resulting from high temperature

Jan 1, 1945

By F. H. Wilson, R. M. Brick

WITH the papers of Palmer and Smith1 and of Burghoff and Bohlen,2 published in 1942, understanding of the problem of the development of ears on deep-drawn brass cups was brought to the point where, from a practical standpoint, producers of brass sheet could keep earing under control. However, these very practical results raised questions concerning the reasons for the observed behavior. Since plastic deformation is fundamentally a function of crystallographic slip, these reasons must be considered in the light of the textures to be found in the annealed sheet. Various attempts have been made to interpret the mechanism of ear formation by correlation with the preferred orientation and the anisotropy of the sheet. However, none of these has satisfactorily explained why ears are usually found in the rolling and transverse directions for copper but at 45° to these directions for brass. This paper offers additional data on these two related subjects and has been divided into two sections. The first section provides a survey of the recrystallization textures of brass as affected by annealing temperatures and prior reductions, and an account of the earing behavior which accompanies these textures. The second section reports new data on the anisotropy that accompanies a characteristic texture for brass and endeavors with partial success to establish the factors that account for the difference in earing behavior between copper and brass. EARING BEHAVIOR OF BRASS Review of Textures The recrystallization texture of severely rolled brass was first reported by Bass and Glocker.3 The preferred orientation to which this texture, obtained from metal annealed at 500°C., was most akin was (113)[112]. This texture has been confirmed by Bauer, von Göler and Sachs;4 Brick;* Brick, Martin and Angier;6 and Cook and Richards7 who, in general, used annealing temperatures under 500°C. Bass and Glocker3 also reported the recrystallization texture at 850°C. to be the same as at 500°C. They analyzed their textures by means of single photograms obtained with white radiation. The photograms for both temperatures are reproduced in their paper, and there is a strong similarity between the two. However, for the latter temperature, the number of spots registered on the film was remarkably large for the grain size to be expected, and the authors made no mention of using a technique that would integrate a large enough area of the specimen to produce so many spots. The only other attempt to determine textures resulting from high temperature

Jan 1, 1945

Geological Survey of the State of Maine, Orono, Me. Joseph Conrad Twinem, State Geologist In the years 1837, 1838, 1839, Charles T. Jackson made three reports on the geology of Maine Reports were made in 1861-1862 by C. H Hitchcock entitled, respectively, "General Report on the Geology of Maine" and "Geology of Maine." These old reports are now out of print

Jan 1, 1933

E. D. WILLIAMSON,* Washington, D. C. (written discussion?).-The paper is interesting and suggestive and the work described should he carried to completion, as it presents points of interest quite apart from the immediate application in glass manufacture. It ought to help, for instance, in throwing light on the chemical nature of glasses and on all questions of viscous flow.

Jan 11, 1919

By John A. Von Essen

To some, the paddle mixer may seem old as antiquity. Yet, as industrial mixing requirements become increasingly sophisticated in the late 20th century, it is proving more useful and versatile than ever. From water treatment applications to high-pressure reactors, the new and specialized demands in mixing have been met by a continuous evolution and adaptation of this basic workhorse design.

Jan 7, 1978

By James T. Curry

FACED with processing an increasing volume of raw material through its existing plant, early in 1955 Calaveras Cement Co. of California considered incorporating liquid cyclones in its raw mill grinding circuits. One of many problems was the prospect of handling larger volumes of finished slurry through existing pipelines. Fixed capacities of the mechanical classifiers also placed limits on plant expansion.

Jan 10, 1957

By George Krauss, Morris Cohen

NUMEROUS investigators1-4 have shown that one of the most conspicuous effects of the reverse marten-sitic transformation in Fe-Ni alloys is the stabilization of the austenite which forms on reversal. However, the present authors5 found a virtual absence of stabilization in a recent study of this subject. The purpose of this note is to account for the discrepancy.

Jan 1, 1963

G. K. BURGESS, ? Washington, D. C.-At the Bureau of Standards it was decided, in order to study the high-aluminum end of these curves, that efforts should be made to prepare pure aluminum, and the promise of getting aluminum, practically free from the two elements that have such great effect in very small quantities, namely, silicon and iron, and which

Jan 12, 1919

By William I. Rau

This presentation will examine the role commercial banks will be expected to assume in financing international minerals projects, including a discussion of various financing techniques such as project loans, production loans, and production payments. A discussion of the necessity for completion guarantees, finalized sales contracts, reserve evaluations, management contracts, and marketing undertakings in conjunction with financing availability are also included.

Jan 1, 1981

By D. S. Choi, H. von Schonfeldt, H. D. Dahl

The design of pillars around a longwall panel in which the effect of the adjacent and worked-out panel is taken into consideration is discussed. A mathematical model is used to duplicate field observations such as opening closure and pillar rib movement. The model is then used to predict the effect of changes in mining geometry on the opening stability.

Jan 1, 1976

By H. C. Meister

The zinc-smelting industry of the United States has grown very rapidly in recent years and bids fair to outrival that of all other countries in the future. On account of the geographical situation of the chief ore-supplies, the industry may be divided into two main groups, the eastern and the western. The eastern and older group includes the works of Penn-

Jan 1, 1905

By D. J. Bourne, G. E. Atwood

The new potash refinery of Duval Sulphur & Potash Co. produced its first tonnage of muriate of potash in November 1951. Full capacity was attained in early 1952. Excellent extraction efficiency is being obtained by the process, which is basically froth flotation. System temperature control is practiced and has proved to be of great metallurgical value through high potassium recovery and low reagent cost.

Jan 11, 1953