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Jan 4, 1976

By David Phillips, George Jura

WHEN Bridgman1 determined the volume-pressure relationships of bismuth to 100 kg Cm-2, he found two small volume discontinuities at 45 and 64 kg em-2. Probably every investigator in high pressures has determined the electrical resistivity of bismuth in this pressure range. Until Zeitlin and Brayman2 reported discontinuities in the resistance of bismuth at these pressures, no one had found resistance discontinuities

Jan 1, 1968

By S. F. Emmons

The first paper which appears in the published Transactions of our Institute is that read by our respected Secretary at its first meeting in Wilkes-Barre in May, 1871. It is entitled " The Geographical Distribution of Mining Districts in the United States," and presents a brief but masterly review of what was known of the distribution of our deposits of useful minerals, particularly the metals, not only from a geographical but from a geological stand-point. At the request of Dr. Raymond I agreed, somewhat hastily, perhaps, to write for this occasion a brief sketch of the geological distribution of the deposits of the useful metals in this country, in the light of the increased knowledge of the present day. In the time given no personal investigation was possible, and as it was therefore out of the question to attempt to make anything that could be considered an original contribution to the history of our ore-deposits, I have been obliged to limit myself to an examination of such pub-

Jan 1, 1894

By Evan Just

THE high standards of living and improved national security that industrialization can bring are so evident that no country can be named that does not cherish the hope of industrializing. With such a universal aim, why do many countries unable to develop their own industries accomplish so little toward attracting the foreign private investor, who alone can provide them with the necessary capital and skill? Obviously, because they fail to under- stand what constitutes a favorable climate for investment, because they have false notions about being exploited or dominated by the foreign investor, or because they are so nationalistic they refuse to permit outside assistance. The purpose of this paper is to aid the citizens and policy makers of developing countries in achieving their aims, by defining the conditions which en- courage investment and portraying the results of a policy of encouragement. The following is quoted from Eugene R. Black, president of the World Bank:

Jan 6, 1957

By O. E. Kiessling

A GROWING uneasiness in the oil fields indicates that doubts are arising as to the efficiency of the present technical, economic and legal arrangements affecting production. Recent documents of the federal government, debates in state legislatures, editorials in the daily press and statements of oil company executives re-echo the notion that the present methods of producing oil satisfy neither the business man nor the public. Such intimations are of utmost importance, since oil is a vital clement in modern industry and dependence upon it increases as new uses develop. SECTION I-PRESENT SCHEME OF COMPETITIVE EXPLOITATION IS WASTEFUL The oil industry has convinced itself, for very good reasons, that the present scheme of competitive exploitation results in losses, both in terms of quantities of oil and in terms of profits. The story of these losses is familiar enough, and it is necessary only to distinguish and summarize briefly certain factors that are of importance to the following argument. Oil pools are exploited under a competitive economic system based on private ownership and contract; the hope of profits attracts capital and enterprise, and competition is supposed to serve as a regulative factor. Whether such a scheme of industrial organization works is partially dependent on the ability of the producer to withhold or produce is commodity as he sees fit, in accordance with the dictates of market demand.

Jan 1, 1927

By Arthur F. Taggart

PROGRESS in a technical art is of several kinds. It springs .from many diverse sources. It comprises invention, mechanical improvement, operating advance, analytical study, education. Invention is, by definition, a relatively great, essentially individual step, taken quickly. Operating advance is the slow, cumulated march of practice; in contrast, it moves at the pace of the tortoise, but over, the years its effects rival and, in some cases, surpass those of invention. Mechanical improvement- is a usual concomitant of the reduction of invention. to operating practice; thereafter it is a primary tool of operating advance. Analytical study is the process of mental digestion of the fruits of invention and practice. Its purpose is to render these into a form assimilable by the art as a whole, and by the perennial crop of would be practitioners. Education, disseminating the results of such study, consolidates and maintains the positions gained. Thus, slowly at first, but continuously accelerating, the tide of progress grows- to flood. Such growth, in mathematical parlance, is expressible in the general form y = mxn, where x is time, n is some positive number greater than one, m is another positive number, and y is the state of the action at instant x. When n is 2, the readers will recognize the graph of the equation as one branch of the familiar square parabola, whose property it is to become parallel to the y-axis; i.e., to move at an infinite rate, in that never-never

Jan 1, 1947

By R. S. Wagner, C. E. Miller, H. Brown

A dc field was applied to liquid BI-Sx or Au-Ge alloys of eutectic composition. The liquid alloys were kept at a temperature slightly above the eutectic. The concentration changes due to electrodijfusion are large enough to cause nuclcation and growth of the primary phases at the respective electrodes. Nearly complete separation of Bi-Sn eutectic was obtained as well as substantial separation of Au-Ge eutectic. The effect of an electric field on the solute distrihn-tion was itluestignted itt tlirectiortally solidified rods of a dilute Bi-Sn (0.5 al. pc,t Bi) alloy. Field-freezing was carried out in small-diameter cupillay tubes to avoid cotuectice mixing -of the liquid. The relative sollcte corzcentratioi, Cs/Co , was rneusred by n radioac1il.e tracer netlod. Cs/Co can be made both largev than unity or srialler than the equilibiuwz distvibrrlion c.oejyicienl, k, , oiler a substattiul portion of the soliclifi&apos;erl rocls. A direct current, passed through a liquid-metal solution, can cause substantial concentration changes by electrodiffusion. The magnitude of the change depends on the difference in ionic mobilities of the atomic species in solution. Electrodiffusion has been studied in many binary and ternary liquid alloys.&apos;y2 It was found that the rate of material transport decreases with time for a constant applied field, as a concentration gradient is established in the solution. A steady-state concentration profile is achieved when electro-diffusion is compensated by chemical diffusion. This may seem to limit the use of electrodif fusion for metallurgical application. However, a way of utilizing the effect of electrodiffusion is to combine it with crystallization or controlled freezing. rakin was first to propose this as a new method of separating metal alloys of eutectic composition at temperatures slightly above the eutectic temperature. It was possible by this method to separate Bi-Sn and Bi-Cd eutectics into their component phases. Angus et al discussed the possibility that the effective distribution coefficient, keff, could be varied by proper application of an electric field during solidification. The combination of electrodiffusion and solidification, called field-freezing, was discussed in detail by Pfann and aner. It was shown that field-freezing can be used as a crystal-growth process, an efficient method for eutectic separation, and a new means of changing the effective distribution coefficient. k,ff, beyond the usual range of ko < k,ff < 1. The liquid layer adjacent to the solid-liquid interface can be either increased or depleted in solute due to

Jan 1, 1967

By R. H. Pemberton

The principle of airborne electroniagnetic prospecting is well-known. &apos;The basic geonhysicai texts in inost cases discuss the main elements involved in electromagnetic prospecting. However. there is ceriainlv iittle information available to the public concerning he present types of airborne eiectromagnerlc systenis being flown today by both contracting companies and some of the mining companies which have their own instruments. This is unfortunate since it is difficuit for those people not conducting such operations to understand thoroughly the iarge variation in the electromagnetic instrunlents available. Basically, the aeriai electromagnetic induction method utilizes a primary or transmitting coil through which is generated an alternating magnetic field at a frequents: generally of the range of 100 to 2000 cycies per sec. This primary field links with buried conductors and generates eddy currents within them. These eddy currents in themselves generate a secondary magnetic field of the same frequencv, but generally nut-of-phase with respect to the prinlarv field. This secondarv field is detected above the ground in the pick-up or receiver coil which is tuned to the frequency of the current applied to the primary transmitter coil. One of the main problems in the development of an airborne electromagnetic system is that of maintaining constant coupling between the cransmitting and receiving coil systems. Any variations in the coupling due to relative motion between the two coils will result in an in-phase signal being induced in the receiver coil. [However, any variation in the coupling does not result in an out-of-phase signal change in the receiver coil. The first airborne eiectromagnetic svsteins which were developed utilized a large prlniarv coil set up on the aircraft with the receiving coil being towed behind in a bird, generally at the end of a cable of about 500 ft. in length. It is possible with such a system to record the out-of-phase or quadrature responses more readily than the in-phase re-sponse. One system utilizes a dual frequency method, wnereby the out-of-phase responses at two frequencies are recorded. Another system used today records a single-frequency olrt-of-phase response. Recentlv home companies have succeeded in measuring from ne air both the out-of-phase and the in-phase components. The usefulness of recording in-phase is weil-known, but unfortunately this is difficult to obtain in any towed-bird system. In order to measure the true in-phase signal, the most straightforward system is that in which both the transmitter and receiver coils .Ire affixed in space so that there is little or no relarive motion between the two coils. THE FLIGHT SYSTEM The particular system which Canadian Aero Service is using at present is mounted on a Sikorsky S-55 helicopter (Fig. 1). A record of both the in-phase and out-of-phase responses is made at a frequency of 390 cycles per sec. The transmitter coil is set on a boom mounted in the front of the helicopter; the receiver is set on a tail boom extending back from the helicopter. Separation between these coils is about 65 ft. The two coils are mounted in a vertical co-axial relationship. Having the transmitting coil in a vertical plane ensures that maximurn coupling will occur with vertical conductors rather than flat-lying conductors. Having them mounted as they are in a co-axial relationship on the helicopter ensures that maximum response will occur when the flight direction is orthogonal to the strike direction of a given conductor. The present sensitivity of the Em system is 20

Jan 1, 1961

By K. G. Davis

Dilute alloys of silzer in tilz haz been solidzjzed a1 controlled rules, in lzorizontal tubes 2 mrz and 0.5 rn in diam. Radioactive; tracer techniques we?-e used to study solute distvihutions along llze specimens and irmpurity substructures, as functions of the conditions growth. The results have heen mzalyzed using Burton, Prim, and Slichter&apos;s tnodel for the solute disty-ihution in the liquid ahead of an advancing solid-liquid interface. DECANTING techniques have been used to establish criteria for the formation of impurity substructure during solidification in several alloy systems An analysis equating the appearance of impurity substructure with the incidence of constitutional supercooling was developed,= in which diffusion was assumed to be the predominant mode of solute mixing in the liquid. Substitution of experimental data into the equations derived from the diffusion analysis gave reasonable values for solute diffusivity in the liquid. However, in these investigations solidification rates of 10 cm per hr and over were used, to minimize the effect of natural conection, whereas for crystals of high perfection lower solidification rates are needed, usually between 1 and 5 cm per hr. A knowledge of the conditions under which impurity substructures will be formed at low growth rates, and the degree of segregation to be expected, is therefore of interest. In the present investigation, radioactive-tracer techniques have been used to study the effect of growth rate, initial solute concentration, and size of specimen on the formation of substructure in uni- directionally solidified rods of dilute silver in tin alloys, over a range of growth rate between 0.5 and 10 cm per hr. Criteria for the formation of substructure were established by auto radiography. This was believed preferable to the decanting technique, for the relationship of the structure on a decanted interface with that of the freezing interface is not clear, since a layer of liquid is left on the surface following decanting.&apos; The effect of substructure on the distribution of solute along the rods was also investigated. EXPERIMENTAL The procedure for sample preparation has been described in detail by einber. Alloys were prepared from tin of 99.999 pct purity and silver of 99.99 pct purity. A"&apos;, an emitter of both y and 0 radiation, was used as tracer. Samples of the alloys were drawn up into silica tubes with inside diameters 0.5 or 2 mm, remelted in a horizontal furnace, and solidified at controlled rates. A few centimeters of the samples were left unmelted for a measure of the initial concentration. Total sample length was approximately 20 cm. The temperature gradient in the furnace was kept constant at 36°C per cm in the region corresponding to the melting point for tin. To find how well this corresponded to the actual temperature gradient in the melt, a thermocouple of 38-gage wire was electrically insulated with a thin layer of Sauereisen cement and placed within one of the 2-mm-diam tubes, which was then filled with tin. The maximum diameter of the coated wire was 0.5 mm, the bead of the thermocouple junction being no larger than the diameter of the wire. A plot of temperature vs distance traveled by the furnace is given in Fig. 1 for a rate of furnace travel of 1 cm per hr. The temperature gradient in the liquid

Jan 1, 1967

By G. Sachs, L. J. Ebert, W. F. Brown

INTRODUCTION ISOTHERMAL transformation, or "austempering," of a carbon-containing austenite at elevated temperatures yields so-called "intermediate products." Their structure and properties are, for a given hardness, rather different from those of "tempered martensite" obtained on conventional quenching and tempering.1 Several investigators2,3 have found that for high carbon and slightly alloyed steels the intermediate products formed at temperatures close to that of the martensite reaction possess strength properties superior to those of tempered martensite. The structure of these low temperature, intermediate products is generally acicular (bainite) but clearly different from that of martensite. However, at higher austempering temperatures, between 1000 and 1300°F (540 and 700°C) carbon steels were found to exhibit a rather low ductility.4-5 Thus notch bar tensile tests showed the ratio between notch strength and regular tensile strength to decrease with increasing austempering temperature. For ductilities below a few percent this notch strength ratio is a measure of ductility, according to investigations on low alloy steels.6-7 Furthermore the presence of intermediate products formed unintentionally on quenching was considered as responsible for the low ductility and impact energy of some heat treated steels.8 These intermediate products could result from partial transformation at the so-called "nose-temperature" where the rate of the transformation is a maximum. Tempering improved such mixtures of martensite and intermediate products, their properties approaching those of tempered martensite of equal hardness. The following investigation constitutes an attempt to determine certain strength properties of a partially austempered and subsequently quenched low alloy steel, namely, a chromium steel (SAE 5140). The structures formed by such a treatment should consist of a mixture of intermediate products formed on austempering and a martensite formed on oil quenching from the austempering temperature. It was intended, by varying the austempering time, to vary the quantity of the intermediate products between zero and 100 pct. The austempering temperature of 860°F was selected after extensive preliminary tests close to the nose-temperature. Austempering at this temperature yielded an acicular intermediate product. Additional tests under less exacting conditions were made for an austempering temperature of 950°F where the intermediate product appeared to be very fine pearlite. To determine the effects of tempering on structures containing various amounts of

Jan 1, 1948

By H. M. Day

THE constitution of the system silver-mercury has attracted the attention of many investigators during the last two decades, but since their results are for the most part in poor agreement, there is little need for a review of their individual contributions. It remained for the very careful thermal and microscopic investigation of Murphy1 in 1931 to give the constitutional diagram in its present and unquestioned form, which is shown in Fig. 1. He devised methods for taking cooling curves on alloys under high pressures and for the microscopic observation of alloys which contained liquid mercury as a structural constituent at ordinary temperatures. The compositions of the intermediate phases were con-firmed and supplemented through X-ray analyses by Preston and Stenbeck.3 According to Murphy, at 276° C. silver is able to dissolve 44 to 45 weight per cent of mercury, which may increase at lower tempera-tures to about 50 per cent. Preston concluded that the saturation boundary occurred at 46 ± 2 per cent at 100° C. From the values reported in the literature, these are the only ones that may be accepted as lying even in the right region.

Jan 1, 1938

By Clarence Merritt

STAINLESS iron, as mild stainless steel is usually called, an alloy ranging from 11.50 to 15.00 per cent chromium with carbon under 0.12 per cent, has been considered to be not appreciably affected in respect to corrosion resistance by heat treatment. This metal, while one of the most widely used of the "straight" chromium stainless alloys, has failed in many applications because of insufficient information regarding heat treatment. These failures have been attributed to many possible causes from an inherent lack of resistance to corrosion and misapplication to mysterious electrolytic effects or comparatively minute non-metallic inclusions. Many uses for a steel with such excellent physical properties is are latent in this alloy have been lost on account of corrosion failures which could have been avoided by applying proper heat treatment. The alloy has not received the recognition or attention it should because of the fact that&apos; the details of its metallurgical behavior were not thoroughly understood. Response to heat treatment of the steel is well known as regards tensile properties, 1,2 but its application has been for improvement in tensile characteristics or on account of machining considerations rather than for corrosion prevention. The potential user of this steel has not been clearly advised in papers, either technical or commercial, that have been written about it in the last 10 years or more, of particular features that are of prime importance in developing the excellent properties of this metal. The data to be presented in this paper are concerned mainly with the effect of heat treatment on the corrosion resistance, but a study has also been made of the concurrent microstructural changes and an explanation developed for the phenomena revealed, as well as a correlation to the other physical properties-hardness, tensile characteristics and impact strength. Stainless steel, largely used for cutlery purposes, an alloy of approximately 13.00 per cent Cr with 0.30 per cent C, must be hardened and the surface prepared by polishing or pickling for best resistance to staining and corrosion.3 Monypenny reports that a loss of hardness is

Jan 1, 1932

By R. J. Wysor

SINCE the outbreak of the European war, few problems of raw-material supply have commanded more nation-wide attention than potash. It is well known that before the war the domestic production of potash was an insignificant percentage of the imports. The average annual importation of raw potash salts for several years prior to 1914 was slightly over 300,000 net tons, and f other potash manure salts about 700,0000 tons. The sudden and almost total cessation f these imports created a unique and stringent situation. Methods of recovering potash from feldspar and other native mineral sources, and reclamation from hitherto waste products, have received a marked impetus. Soaring prices have been a keen-incentive to research and industrial development. Although several brief articles concerning the possibilities of potash recovery have appeared in recent trade journals, it still may be a matter of some surprise to the average technical mind that potash might be reclaimed as a profitable byproduct in the manufacture of pig iron. At the present time it may be of special interest to present some data, largely of a technical nature, on this subject. A fairly thorough search of the literature reveals a number of articles concerning salts of the alkali metals in the blast furnace. Many of them deal with the-theoretical role f alkali cyanides in the furnace. Several discuss the, probable effect of the alkalies on the furnace brickwork. Two or three ambitious patents have been granted for reclaiming potash or other products from blast-furnace gas. However, we have heard nothing further as to the practical application of these patents. Little literature of importance has appeared during the last 10 years concerning alkalies in blast-furnace practice, and I have discovered no record whatsoever as to the actual sale or commercial disposal f flue dust for its , potash content until this was inaugurated in our plant at Bethlehem. A bibliography of the most important articles discovered is appended.

Jan 1, 1917

By Feridun A. Albayrak

Jan 1, 1985

By J. Husson, R. Iffly, M. Gondouin

A systematic variation of well deliverability, as reflected from isochronal back-pressure tests performed at regular intervals, has been observed in some gas condensate wells producing at high rates. The same effects have been obtained using a numerical model of gas and condensate flow which takes into account secondary gasoline deposited in the pore space as a result of pressure reduction, and non - Darcy flow of gas in the vicinity of the wells. Matching calculated values with previous test results has been possible, and future predictions have been obtained. An application of this method to the Hassi Er R&apos;Mel gas-condensate field in Algeria is tentatively shown. INTRODUCTION Flow capacity of gas wells is generally derived from an analysis of back-pressure tests. The empirical equation q = C (?p2)n used by Rawlins and Schellhardtl can be derived rigorously assuming that steady-state radial flow of a dry gas of constant viscosity and compressibility is established during each flow period of the well tests. Furthermore, when Darcy&apos;s law applies in the entire flow region, the theory predicts that the exponent n is equal to 1. In low-permeability reservoirs, it was soon discovered that the time required to reach a stabilized flow often exceeded the duration of the flow periods normally available for testing wells. Consequently, transient gas flow had to be considered instead of the steady-state assumption previously used. This led to the isochronal testing procedure established by Cullender2 which has largely replaced conventional back-pressure testing. For dry gas fields, this method yields definite values of C and n equivalent to those of the empirical equation. These values should remain constant for each well as long as the permeability of the formation and the characteristics of the gas (viscosity and compressibility) do not change appreciably. This is the case when reservoir pressure remains -close to the original value and when the formation near the wellbore remains free of plugging. Under those conditions, stabilized flow potential curves of gas wells can be established from a single sequence of isochronal flow and shut-in periods. An analysis of a pressure build-up following a longer production period provides additional data on the transmissivity (k h/ u) of the reservoir, and eventually on the &apos;drainage radius rd of the well, which can be related to the value of C so that future performance of the well can be predicted using the concepts developed by A. Houpeurt.3 At high flow rates, Darcy&apos;s law no longer applies in the vicinity of the wellbore, and inertial effects in the high velocity gas flow introduce additional pressure drops. As a consequence, exponent n of the backpressure tests becomes smaller than 1, and a slight curvature of the log-log plot of ?p2 vs q can be predicted when going from very low to high rates of flow (Elenbaas and Katz).5 The effects of variations of viscosity and compressibility with pressure on the radial flow of dry gas in an infinite reservoir were taken into account by Jenkins and Aronofsky.7 Numerical solutions of the transient flow of an ideal gas in finite radial reservoirs were presented by Bruce, Peaceman, Rachford and Rice.8 In the case of gas condensate wells, however, the presence of gasoline in the pore space as soon as reservoir pressure is reduced below the dewpoint pressure further complicates the interpretation of flow tests so that the prediction of stabilized well performance becomes very difficult. Field observation shows that both C and n derived from isochronal tests vary in time, even when reservoir pressure has not changed appreciably. Such a variation cannot be attributed to any change of the gas characteristics, and must result from the effect of a gasoline saturation on the gas flow.

By J. M. W. Mackenzie

The interactions between oil drops and mineral surfaces have been examined for the cetyltrimethylammonium bromide (CTAB)-quartz and sodium dodecyl sulfate (SDS)-hematite systems. The results have been interpreted using a electrical double layer interaction model, a "sweeping-penetration" model based on steric interactions and a free energy of adhesion model. The adsorption of long-chain ions at the mineral interface was also studied and found to follow a Fuerstenau-Modi model of combined Coulombic and chain-chain interaction forces. The basis of the emulsion flotation process and the feature which makes it differ from conventional flotation is: encounter, followed by adhesion, between oil drops and mineral particles which are suspended in an aqueous environment. The manner in which the adhesion between these two phases contributes to the flotation process may be through the formation of min-eral-oil drop-mineral linkages, mineral-oil drop-air bubble linkages, or a combination of both. Possible flotation mechanisms derived from these adhesion processes are shown schematically in Fig. 2 while Fig. 1 shows an example of the first mechanism for quartz particles which have been floated using a cetyltrimethyl-ammonium bromide (CTAB)-Nujol emulsion as collector. In Fig. 2 the three phases, mineral, oil, and air, for convenience have been shown as having approximately equal size. This would not always be the case in an actual emulsion flotation operation. For the flotation of sand-sized particles of approximately 0.5 mm diam, the mineral particles would be at least ten times the size of the largest emulsion drops present in the system, while in the flotation of —10u slime particles, the mineral phase may be of the same order of size as the oil phase. The air bubbles in a flotation cell are normally about 1 to 2 mm in diam and therefore, in general, would be larger than the oil drops. Although the relative size of the three phases does not alter the basic adhesion processes between oil drops, mineral particles, and air bubbles, which depend on the physical and chemical properties of the interfaces involved rather than on the extent of these interfaces, it does alter the degree of deformation of the oil drops and air bubbles which will occur on adhesion. For mechanisms 1 and 2 to take place, the oil-water and mineral-water interfaces must be partially replaced by a mineral-oil interface while in mechanism 2 there is the additional requirement that the oil-water and air-water interfaces must be replaced by an oil-air interface. In view of the importance of the oil drop-mineral particle encounter and subsequent adhesion stages to both of the emulsion flotation mechanisms discussed, a study has been made of some physicochemical factors which control these processes for Nujol-cetytri-methylammonium bromide (CTAB)-quartz and Nujol-sodium dodecyl sulfate (SDS) -hematite systems. Experimental Electrokinetic Measurements.—The zeta potential of mineral particles was measured using a streaming potential technique similar to that described by Fuerste-nau.1 The streaming potential was measured using a multirange electrometer while the plug conductivity was measured using a 50 cycle sec1 bridge. Measurements were made on 28 x 65 mesh particles. Contact Angle Measurements.—A captive bubble technique was used to measure the contact angles for air bubbles and oil drops. The angles were measured on fracture faces of unmounted minerals which proved easier to clean than polished mounted specimens and should more closely represent a flotation system. Reagents: These have been described in a previous publication.0 Minerals: Rock crystal quartz from the New England district, N.S.W., was used for contact angle and streaming potential measurements. The quartz was hand

Jan 1, 1971

By George Comstock

THESE notes should be considered as a further discussion of Mr. S. W. Miller&apos;s paper on "Some Structures in Steel Fusion Welds."1 In that paper and the resulting discussion; several conflicting opinions were expressed as to the identity of the needles or small crystals present in oxyacetylene and electric welds. An interesting specimen of an electric weld examined by the writer seems to afford new evidence regarding the needles, that may be worth presenting at this time. The specimen consisted of a piece of 3/8 -in. (9.5-mm.) steel plate, about 2 ¼ by 1 ¾ in. (5.7 by 4.5 cm.) in size, on which some iron had been deposited by arc-welding to a depth of about 3/16 in. (4.7 mm.). The weld appeared to be a very good one, with no noticeable break or boundary between the plate and the deposited iron. Sections for microscopic examination were cut in three planes at right angles to each other through the deposited metal, two of these sections also extending through the steel base. After polishing in the usual way, the microscope showed that the deposited metal was full of very small, round, gray, oxide spots, while the steel plate contained quite a number of alumina inclusions and a little slag. The sections were etched with nitric acid in ordinary alcohol, and structures similar to those described by Mr. Miller were then displayed. Fig. 1 shows the typical appearance of the deposited metal, which was quite uniform in all three of the planes examined. The round dark-gray spots are oxides, and the pale angular crystals are evidently what, Mr. Miller called cementite and Mr. Jeffries martensite, while Dr. Ruder and Prof. Boylston suggested that they might be nitride. The boundary between this structure and the steel base was sharply defined under the microscope. Fig. 2 shows the structure of the plate just under the weld; this is almost martensitic and resembles a coarse-grained casting. This coarse cast structure soon became finer as the distance from the weld increased, finally, becoming very fine, with numerous small particles of sorbite. This very fine structure, shown in Fig. 3, became coarser in turn and finally merged into the original normal structure of the steel plate, shown

Jan 1, 1919

By Reno Sales

THE present-day application of geological knowledge to mine opera-tions owes much to Survey activities. Early publications covering developed deposits at Comstock and Eureka in Nevada, and Leadville in Colorado, aroused great interest in mine geology among mine owners and operators. In later years personal contacts between Survey geologists, notably Lindgren, Spurr, Emmons, Weed, and Ransome, to name only a few, and mine managers, mine superintendents and mine foremen, brought directly home the importance of geological mapping and study in connection with mine operations. However, the Survey had recognized from the beginning that it was not practicable, either from the viewpoint of cost or policy, to supply direct help to the miner. The situation was met by many large mining companies through the organization of geological departments to deal with problems of geology which concerned not alone the every-day mine operation but also the life expectancy of the ore deposit. The mine owner therefore looked to the mine geologist to apply the "laws of ore deposition" in estimating the future of his mine. The examination of outside properties also became a duty of the company geologist where replacements were needed or where expansion of operations was contem-plated. And finally, out of this situation there developed the inde-pendent consulting geologist, specializing in geological examinations of prospects, mines, and mining districts, whose duties included the highly important but often difficult task of appraising ore reserves and ore possibilities. Thus, while it may be considered by many that the work of the mine geologist overlaps that of the Survey geologist, their respective fields of endeavor are not in conflict. The appearance of the mine geologist has lessened in no manner the need of intensive field and research work by the Geological Survey and related organizations.

Jan 1, 1934

By H. W. Mossman

Three aspects of magnetite smelting are discussed. The first is the working out of equilibrium conditions for eliminating sulfur. The second is the influence of magnetite solubility on the difficulty of tapping the reverb matte. The third is an approximation of the equilibrium conditions in the reverb gases which govern whether magnetite is mode or reduced in the reverb slag by these gases and by any iron sulfide in the slag. MAGNETITE has had a varied history in the Hurley Smelter since its start in 1939. Magnetite determinations on the smelter products are made regularly only on the monthly composite samples. Variations on the monthly averages are shown in Table I. Magnetite which drops from the slag and matte in the reverb has some slight bottom buildup which comes and goes, but no substantial accumulation from this source has been found at the end of a normal nine months&apos; furnace campaign. However, there has been some low grade magnetite bearing material mixed with considerable A1,0,, which has slid down from the bottom of the sloping flue between the reverberatory furnace and the waste heat boilers. This accretion has required drilling and blasting near the skimming end of the furnace. The magnetite has interfered with tapping at times. When the smelter was first started, tapping trouble from magnetite was extremely severe. Increasing the reverberatory furnace temperature by putting in an air preheater and a Dutch oven has helped greatly, although there still is occasional tapping trouble. When the present series of physical chemistry articles on copper smelting started coming out in 1950, they were read with interest, but no immediate application was seen for them. Results of some laboratory work in 1952 aroused a much stronger interest in this physical chemistry. A series of melts was made on some converter slags, which had magnetite in very large grain sizes, with the object of reducing the grain sizes in the slag, as it was known that it was easier to handle in the reverb in that condition. Anything done in the tests greatly reduced the grain sizes—even in the controls, where nothing was done except melt the slag and cast it. There was more magnetite in the slags after the tests than before, and with wide variations. There were no obvious reasons lor much of what happened in these tests. Much of the base material published in English in this field was made available for study. Recalculations were made on many of the type problems, and part of the data was reduced to local temperatures and compositions. Explanations were found for what happened in the 1952 series of tests on converter slags, and the same principles turned out to be a description of much of what magnetite does in the reverb. This article is to present the results of that study, from the viewpoint of applying the technical material in definite numerical form to the operating conditions in both the converters and the reverberatory furnaces at the Hurley smelter. Table I. Magnetite Variations on Monthly Averages, 1939 to 1955 Pet Magnetite Lowest Highest Average Converter slag 13.6 43.3 25.4 Roverb slaa 2.7 20.9 8.7 Matte 28 15.9 98 In general it was found that magnetite is made or reduced in both the converters and the rever-beratory furnace, depending on variations of temperature, matte composition, and reverb gas composition occurring in ordinary plant operation. Within reasonable limits, the field conditions for formation or reduction can be predicted, and probably can be set up and maintained. Converter conditions affecting magnetite formation can be put into numerical values better than for the reverb from purely technical calculations. The converter can be operated so as to keep the magnetite in the slag down to between 12 and 14 pct and still give satisfactory life for the converter brick. This depends upon having converter flux available which will make a slag with a good separation without raising the temperature too high. In the Hurley reverb and others with similar conditions, it is likely that a compromise of conditions will give a reasonably good control of combustion and still keep the magnetite from building up on the bottom. This discussion consists of three main parts. The first is the working out of the equilibrium conditions in the converter for determining in which direction the reaction 3 Fe,,O, (s) + FeS (1) F? 10 FeO (1) + SO, will go under actual converter operating conditions. The second deals with the influence of the solubility of magnetite in the slag and matte in the reverb on the difficulty of tapping matte. The third is an approximation of the equilibrium conditions in the

Jan 1, 1957

By Jack C. Bokros, Philip C. Rosenthal

DEVELOPMENT of the autoradiographic method in metallurgical research has been directed mainly toward gaining higher resolution, i.e., toward being able to locate segregation of a radioactive isotope on a finer scale. In the investigation reported, the liquid emulsion autoradiographic technique&apos; used in the biological science was adapted to the autoradiography of metals. The distribution of carbon-14 in pure iron after various treatments was studied using this technique. Amorphous carbon uniformly labelled with carbon-14 at a specific activity of 6.95 microcuries per millimole was obtained from Tracerlab Inc. Carbon-14 emits P particles having a maximum energy of 157 kev and an average energy of about 50 kev. These ßs have a maximum range of about 30 mg per cm&apos; and a half-thickness of about 3 mg per cm2. The iron used was spectroscopically pure electrolytic iron prepared by the Oak Ridge National Laboratory. Unhardened nuclear track emulsion, type NTB, was kindly supplied by the Eastman Kodak Co. This emulsion contains approximately 80 pct Ag halide,

Jan 1, 1957