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By J. Russ, C. L. Clark

For many years attempts have been made to develop a laboratory test that would serve to indicate the proper temperatures to be used in the various hot-working applications to which metals may be subjected as they are being processed from the cast ingot to the desired finished products. That these attempts have not been very successful is indicated by the fact that most of the temperatures in use today in these operations have been developed over a period of years by trial and error. In other words, the selection of the proper temperatures for the hot-working of metals is generally an art rather than a science. Our knowledge with respect to the behavior of metals at elevated temperatures has been greatly extended during the past several years. While most of the work in this field has been done at proposed operating temperatures of equipment, rather than at processing or fabricating temperatures, one outstanding fact has been developed, which is applicable to the entire high-temperature range; that is, that the rate of deformation to which the metal is subjected is of the same order of importance as the temperature. The failure to properly recognize this fact has greatly retarded the development of a suitable laboratory test for determining hot-working temperatures. Influence of Rate of Deformation on High-temperature Properties It is not the intent of this paper to survey all the work that has been done On the effect of deformation rate On the properties of metals. The importance of this factor, however, was shown by Zay Jeffries' as early as 1919, when he called attention to the existence of the so-called equicohesive temperature and to the effect of certain factors on the location of this temperature' Fig. I is a diagrammatic sketch showing the effect of temperature On the relative strength of the crystals and grain boundaries and the type of fracture that will res depnding On the location of the test, or Or temperature with respect to the equicOhesive temperature. Since the type fracture varies, it also follows that at temperatures below the equicohesive temperature the major deformation occurs in the grains: while at temperatures above, the deformation results either from the movement of the grains with respect to each other or recrystallization of the strained material occurs almost instantaneously, producing new crystals at the fracture. As previously indicated, it is an established fact that the position of this equicohesive temperature for any given metal is dependent On the deformation rate' For example, in 0.15 per cent plain carbon steel the location of this temperature under

Jan 1, 1947

By C. L. Clark, J. Russ

For many years attempts have been made to develop a laboratory test that would serve to indicate the proper temperatures to be used in the various hot-working applications to which metals may be subjected as they are being processed from the cast ingot to the desired finished products. That these attempts have not been very successful is indicated by the fact that most of the temperatures in use today in these operations have been developed over a period of years by trial and error. In other words, the selection of the proper temperatures for the hot-working of metals is generally an art rather than a science. Our knowledge with respect to the behavior of metals at elevated temperatures has been greatly extended during the past several years. While most of the work in this field has been done at proposed operating temperatures of equipment, rather than at processing or fabricating temperatures, one outstanding fact has been developed, which is applicable to the entire high-temperature range; that is, that the rate of deformation to which the metal is subjected is of the same order of importance as the temperature. The failure to properly recognize this fact has greatly retarded the development of a suitable laboratory test for determining hot-working temperatures. Influence of Rate of Deformation on High-temperature Properties It is not the intent of this paper to survey all the work that has been done On the effect of deformation rate On the properties of metals. The importance of this factor, however, was shown by Zay Jeffries' as early as 1919, when he called attention to the existence of the so-called equicohesive temperature and to the effect of certain factors on the location of this temperature' Fig. I is a diagrammatic sketch showing the effect of temperature On the relative strength of the crystals and grain boundaries and the type of fracture that will res depnding On the location of the test, or Or temperature with respect to the equicOhesive temperature. Since the type fracture varies, it also follows that at temperatures below the equicohesive temperature the major deformation occurs in the grains: while at temperatures above, the deformation results either from the movement of the grains with respect to each other or recrystallization of the strained material occurs almost instantaneously, producing new crystals at the fracture. As previously indicated, it is an established fact that the position of this equicohesive temperature for any given metal is dependent On the deformation rate' For example, in 0.15 per cent plain carbon steel the location of this temperature under

Jan 1, 1947

By W. M. Courtis

This district commences near Pigeon River, the northeastern boundary between Minnesota and Province of Ontario, and extends entirely around the north shore of Lake Superior, terminating for the present at the Bruce Mines on Lake Huron. The discoveries of mineral-bearing veins have been confined for the most part to the lake shore, or to the country opened up by the Dawson Red River road. As yet the country back from the lake has been but little explored, on account of its roughness, being intersected by steep, rocky trap bluffs, 1000 or more feet high, and alternating white cedar and tamarack swamps. The forests are exceedingly difficult for prospectors. In many places Titanic piles of rocks, protected by chevaux-de-frise of dead cedars, with their hooked, tough, sharp branches, and a covering of spongy moss, sometimes several feet thick, successively guard against the discovery of hidden treasure. The Hudson's Bay Company for nearly a century have maintained trading-posts at Fort William and other points, which probably opened the way to the first discoveries that were made at Prince's Bay, near the western limit of the district. At this point a large vein was worked by Colonel Prince, the owner, as early as 1846. The richest part of the vein seems to have been on Spar Island, but work was stopped on account of excess of water. Sir William Logan states that a mass of ore weighing several hundred pounds and carrying 3 per cent. of silver was taken out. On the mainland small quantities of native and sulphide of silver were found, together with iron and copper pyrites, zinc blende, and galena, in a large spar vein. On the main shore a drift 165 feet long and 90 feet in depth

By Frank H. Macpherson

Few people realize the tremendously important part that Saline and Pulaski Counties in central Arkansas have played in the winning of the war The present favorable war situation might have been very different if we had not had the bauxite produced during the past two years from these two small areas, a total Of about 15 square miles. As a general statement, it can be said that the Arkansas bauxite deposits are, individually, relatively small, irregular in thickness, somewhat scattered and, therefore, compared with coal or iron-ore or open-pit copper deposits, relatively ill adapted to a rapid and drastic expansion in output. A few years ago it would have seemed an impossibility for these two counties to produce over six million long dry tons of bauxite in one year. However, with the cooperation of the operators, that is what happened in 1943, when the state of Arkansas achieved the seemingly impossible with a production of 6,020,684 1 long tons (dried equivalent) of bauxite ore during the calendar year, compared with an average annual production of 323,7252 tons in the period 1931 to 1941. It became apparent early in the year '94' that the united States soon might be drawn into the war, and, therefore, that an immediate study of the domestic metal situation was necessary. Aluminum is by far the most important metal used in the manufacture of aircraft and many other implements of war and it was evident that there would have to be a tremendous increase in the domestic production of bauxite, which is practically the only present source of this metal. AS more than 95 per cent of the known bauxite reserves of the United states was in Arkansas, careful preliminary studies were made in that state by representatives of the united States Bureau of Mines, the United States Geological survey and the War Production Board in the summer of 1941 Reserves in other states also were studied. The result of these studies was a recommendation by the War Production Board that mining in the bauxite.producing areas of Arkansas be geared for maximum production, in order to supply sufficient ore for this country's war requirements and, if necessary, to supply the war needs of Canada as well. The annual goal of eight million long tons (dry weight) set for Arkansas by the war Production Board was exceeded in 1943, when in August the output reached a rate equivalent to more than 8,300,000 long tons, dry basis. Because of the comparatively small tonnage of bauxite reserves, Congress appropriated funds for an extensive drilling program to be carried out by the Bureau of Mines in cooperation with the Geological Survey. Drilling began in May 1942 but owing to delay in delivery of drills, and trucks upon which the drills were mounted the program did not get into peak operation until early in 1943. By the end of July 1944, the Bureau of Mines records indicated an addition to the Arkansas reserves of 10,000,000 long tons (wet basis) in place,

Jan 1, 1946

By J. Szekely, V. Stanek

Steady state heat transfer and fluid flow rates are predicted for the counter-current contacting of gas and solid streams. For a .fixed pressure drop across the bed the convective heat transfer rate is affected by the gas flow rate, which in turn is affected by the temperature distribution in the system. Variations in bed voidage and in particle size were found to change the predicted temperature profiles quite markedly, in particular when the thermal capacities of the gas and solid streams were equal. IN Part I we examined the effect of step and pulse changes in the inlet gas temperature on transients in the flow of gases through fixed packed beds. Here we shall discuss heat flow and fluid flow interactions in the counter-current heat exchange between packed solids and a gas stream. Counter-current heat exchange in packed beds has been extensively studied. In his now classical paper, Furnas' assumed constant property values and developed a simple analytical. expression for the temperature profiles in the gas and in the solid stream. A highly sophisticated analysis of counterflow systems, allowing for transients and interparticle conduction was developed by Amundsen. In preparing a very readable review of this topic Elliott' also presented a number of elegant solutions, including the case involving heat generation. A great deal of work has been done on the application of these concepts to the modelling of the blast furnace. However, in all this previous work the mass flow of the gas was regarded as a quantity independent of the gas-solid heat exchange process. In the following we shall consider counter-current heat exchange between a gas stream and a packed bed of solids, under conditions where the pressure drop across the bed is specified, rather than the mass flow of the gas. FORMULATION Consider a packed bed, extending from y' = 0 to y' = L, in which moving solids and a moving gas are contacted in a counterflow arrangement. Let cold solids, with an initial temperature Tsi and mass flow GA, enter at y' = L, and hot gas with an initial temperature of Tgi and mass flow Gg enter at y' = 0. In contrast to the problems considered in Part I this system has a nontrivial steady state and we shall restrict our attention to the study of the pressure drop flow relationships and the resultant temperature distributions for steady state conditions. Under these conditions the formulation of the problem requires the statement of the following: 1) heat balance on the gas 2) heat balance on the solids 3) the mechanical energy balance equation and in addition the knowledge of the equation of state, and a functional relationship between viscosity and temperature and an expression for the heat transfer coefficient in terms of the other parameters. On neglecting temperature gradients within the solids and for a constant mass flow of the gas, the solution to this problem is well known.'" The expressions for the temperature profiles of the gas and solid streams may be put in the following form: where Tg and T, denote the dimensionless gas and solid temperatures respectively, y is a dimensionless distance, and R is the ratio of the thermal masses. These quantities are defined as follows: For the particular case of equal thermal mass capacities by the gas and the solid, that is R = 1, the Eqs. [1]and[2] simplify to Eqs. (71 and[8], respectively: i.e., the resultant profiles are linear. As for most practical cases , solutions given by Eqs. [7] and [8] will contain only the inlet temperatures as parameters. For a fixed, predetermined value of C;b the above

Jan 1, 1970

By J. F. Radavich

Many heats of steel of low carbon value have been known to produce brittle pieces of steel. The brittleness is believed to be due to the impurities located within the grain boundaries. Such brittle steels have been examined with an optical microscope to ascertain the nature and the amount of the impurities present at the grain boundaries. Due to the relatively low resolving power of the optical microscope, the impurities are not visible in fine detail. The writer obtained some sheet steel and proceeded to determine the location of the impurities and to show the application of the electron microscope to the study of grain boundaries. One sample was known to be capable of becoming embrittled, whereas another sample was believed to be much less susceptible to embrittlement. Treatment of Specimens The specimens were embrittled by annealing above the A3 point under mildly oxidizing conditions. One piece of ingot iron could not withstand a 90" bend, whereas another piece of ingot iron was not affected and could withstand a 90" bend. The brittle piece was then annealed at a high temperature in a hydrogen atmosphere. The annealed ingot iron was termed cured and could withstand a 90" bend very easily. The three specimens examined will be designated as brittle, good. and cured in the discussion that follows. Procedure The sizes of the specimens were as follows: one piece of brittle ingot iron-3/8 by 35 in.; one piece of good ingot iron-96 by 1/8 in.; one piece of cured ingot iron-36 by 54 in. The specimens were too small to be polished by hand and therefore were mounted in bakelite. The polishing procedure was carried out in the conventional manner with the use of 1/0 through 3/0 papers, and the final polish was done with alumina on a billiard cloth. The specimens were then etched in a 4 pct solution of picral in alcohol, and then they were examined through an optical microscope. An area was chosen that showed distinct grain boundaries, and an effort was made to keep near this area when pulling the replicas REPLICA TECHNIQIJE The replica technique used in the preparation of the replicas for examination under the electron microscope is described in Electron Metallography.' It consists essentially of the following steps: 1. Obtaining a suitably etched specimen. 2. Applying a swab of ethylene di-chloride on the surface. 3. Applying a formvar solution on the surface. 4. Placing a screen on any desired spot. 5. Breathing on the fornivar layer. 6. Applying scotch tape on the screen and film. 7. Pulling the film and the screen up with the Scotch tape. 8. Separating the screen from the Scotch tape. This replica technique is very similar to the one described by Harker and Shaefer. However, with the added step, the percentage of replicas removed is very much higher regardless of the length of the time from the etching of the specimen to the actual pulling of the replica. The replicas were then shadow cast with manganese at a filament height to replica distance ratio of 1 1/2:7. This produced a very high contrast replica for use in the electron microscope. One of the dificulties encountered with this study was the restricted area of the specimen. The width of the specimens was the same as that of the 200 mesh nickel supporting screen. In order to increase the effective area, the screens were cut down as shown in Fig 1. The arrow indicates the direction in which the replica was pulled. This operation made it possible to obtain a large percentage of good replicas. Fig 3 shows an electron micrograph of a brittle piece of ingot iron and a grain boundary that was polished mechanically. The surface is very rough probably due to the incomplete removal of the flowed layer by the picral etchant. The grain boundary does show evidence of impurities. It was decided to electropolish the specimens to obtain a much smoother surface than the one obtained by mechanical polishing. ELECTROPOLISHING The specimens were cut in half to expose the metal on the back side. The exposed metal had sufficient area to make good electrical contact and electropolishing was carried out easily. The conditions for electropolishing were 0.9 amp, 35 volts, and 25 sec. in an electrolyte composed of 850 cc of ethyl alcohol, 100 cc distilled water, and 50 cc of perchloric acid. The polished specimens were then etched in the 4 pct picral solution for a shorter time than was necessary for

Jan 1, 1950

By H. T. Clark

NO previous determinations of the deformation or recrystallization textures of titanium or of titanium-base alloys have been reported in the literature. The room-temperature structure of titanium is hexagonal close-packed with a c/a ratio less than 1.633. It would be expected, therefore, to have a rolling texture similar to that of other hexagonal close-packed metals, namely (0001) [1010]. Burgers and Jacobs1 have shown that zirconium, a metal isomorphous with titanium in its structure and similar in many of its properties, has such a texture with a scatter of the basal plane toward the transverse direction. This scatter is in the opposite direction from that found in magnesium by Bakarian2 but similar to that reported by Smigelskas and Barrett3 or beryllium. The rolling and annealing textures reported here for high-purity iodide titanium are significantly different from the . textures of any other hexagonal close-packed metal. All titanium used during this investigation was prepared by the iodode process." The annealed hardness of this material varied from 73 (material used for sample No. 2) to 97 Vickers hardness number. An estimate of the chemical composition of this grade of titanium has been reported by Finlay and Snyder.5 With one exception, shown in table I, the as-deposited titanium was cast into 10 to 20 g ingots in an electric arc furnace in purified argon before being rolled to sheet. The cast ingots were forged and ground until their cross-section was approximately rectangular, annealed 1 hr at 700°C in vacuum and cold rolled. Rolling was carried out in a two-high, 4 in. diam mill, using reductions no greater than 10 pct per pass. The direction of rolling was reversed after each pass, and, in order to avoid temperature effects, the sheet was allowed to cool after each pass. Unless the rolled sheet was sufficiently thin for X-ray penetration (about 0.004 in.), it was reduced to this thickness by pickling. Because of the possibility of introducing twinning or other deformation during grinding, no attempt was made to maintain uniform thickness of the sample during pickling by intermediate grinding or sanding operations. Those samples to be used for determining the annealed texture were recrystallized by vacuum annealing the cold-rolled sheet for 1 hr at 500°C. These thin samples were held between thick titanium sheets during annealing to prevent distortion. Table I outlines the rolling and annealing schedule of those samples for which photograms or texture patterns are shown. X-ray Techniques The usual techniques for determining textures were employed during this work. Molybdenum radiation was used for the transmission exposures and copper radiation for the glancing angle ones. Since titanium fluoresces under these conditions, it is necessary to employ a filter between the sample and the film. The Kß radiation filters are very satisfactory for this purpose. Sufficient grains having favorable orientation were present in both the cold-worked and in the cold-worked—500°C annealed samples to provide satisfactory patterns with the samples stationary. Because of the difficulties of comparing intensities of transmission photograms with those obtained

Jan 1, 1951

By V.K. Zworykin

Throughout its development the science of electronics, like so many other branches of science and industry, has been indebted to the metallurgist. Metallurgy has provided the electronic engineer with conductors to furnish passage for electrons outside of his evacuated tubes: it has developed tungsten and tantalum wires for emitting electrons and various refractory metals and alloys suitable for electrodes, which receive them and guide them within the tube; finally it has supplied ferromagnetic materials both for shielding electronic apparatus from magnetic fields and for forming highly concentrated fields for deflecting electron . Today I hope to show you that electronics has not been altogether ungrateful for this assistance. More specifically, I wish to indicate the role that the electron microscope, a relatively recent product of electronic engineering, is playing even now in the study of metals. Every metallographer is aware that his standard metallographic microscope will not reveal structural detail involving separations smaller than a certain fraction —at the very best a tenth—of a micron. This limitation, he knows, is a consequence of the fact that the wave length of the light employed for forming the image has this order of magnitude. It is, thus, a property of all light microscopes. TO overcome it, a different imaging medium must be employed, The existence of such a medium became evident when it was demonstrated1 that electrons were affected by magnetic and electric fields with axial symmetry just as light is affected by glass lenses; these fields, or "electron lenses," curve the paths of electrons reaching them from an object located on the axis of symmetry in such a manner that, at some distance from the lens, a true image of the object is formed. Furthermore, although a wave length may . be ascribed to electron beams just as to light, this wave length is much shorter; for electrons accelerated through a difference of potential of 50 kilovolts, the wave length is only about one hundred-thousandth of that of visible light. Actually, the elcctron microscopes of today resolve detail one hundred times as fine as light microscopes; if the maximum useful magnification of the latter is taken to be a thousand, that of electron microscopes is one hundred thousand. The Electron Microscope Since electrons are readily scattered and absorbed by matter, specimens to be observed in the electron microscope must be prepared to be less than one micron in thickness; furthermore, the interior of the microscope must be carefully evacuated to prevent collisions between the clectrons and the molecules of the air. Finally, as already mentioned, the lenses are formed by axially symmetric magnetic or electric fields, and not by any material medium such as glass. Apart from these basic differences, the electron microscope closely

Jan 1, 1943

By V. K. Zworykin

Throughout its development the science of electronics, like so many other branches of science and industry, has been indebted to the metallurgist. Metallurgy has provided the electronic engineer with conductors to furnish passage for electrons outside of his evacuated tubes: it has developed tungsten and tantalum wires for emitting electrons and various refractory metals and alloys suitable for electrodes, which receive them and guide them within the tube; finally it has supplied ferromagnetic materials both for shielding electronic apparatus from magnetic fields and for forming highly concentrated fields for deflecting electron . Today I hope to show you that electronics has not been altogether ungrateful for this assistance. More specifically, I wish to indicate the role that the electron microscope, a relatively recent product of electronic engineering, is playing even now in the study of metals. Every metallographer is aware that his standard metallographic microscope will not reveal structural detail involving separations smaller than a certain fraction —at the very best a tenth—of a micron. This limitation, he knows, is a consequence of the fact that the wave length of the light employed for forming the image has this order of magnitude. It is, thus, a property of all light microscopes. TO overcome it, a different imaging medium must be employed, The existence of such a medium became evident when it was demonstrated1 that electrons were affected by magnetic and electric fields with axial symmetry just as light is affected by glass lenses; these fields, or "electron lenses," curve the paths of electrons reaching them from an object located on the axis of symmetry in such a manner that, at some distance from the lens, a true image of the object is formed. Furthermore, although a wave length may . be ascribed to electron beams just as to light, this wave length is much shorter; for electrons accelerated through a difference of potential of 50 kilovolts, the wave length is only about one hundred-thousandth of that of visible light. Actually, the elcctron microscopes of today resolve detail one hundred times as fine as light microscopes; if the maximum useful magnification of the latter is taken to be a thousand, that of electron microscopes is one hundred thousand. The Electron Microscope Since electrons are readily scattered and absorbed by matter, specimens to be observed in the electron microscope must be prepared to be less than one micron in thickness; furthermore, the interior of the microscope must be carefully evacuated to prevent collisions between the clectrons and the molecules of the air. Finally, as already mentioned, the lenses are formed by axially symmetric magnetic or electric fields, and not by any material medium such as glass. Apart from these basic differences, the electron microscope closely

Jan 1, 1943

several days before leaving Buffalo; influenza developed, and when his train reached Nashville, Tenn., he was too ill to continue his journey and was taken to the Kissam Hall Hospital, Vanderbilt University, where he died of pneumonia. He was a young man of unusual ability and high moral character, always brigh.t, happy and kind, faithful and honorable in all things; loved by both his associates and those under his authority. His life and character cannot be better described than by the following quotation from one of his superior officers: "Lieutenant Ohnsorg was a man loved by all of us, always cheerful, just and kind, with unusual executive ability. We can never expect to find a man who has his ability and fine temperament and his position can never be sled as he filled it." He was happily married and leaves to mourn his loss a wife, Constance E. (Rogers) Ohnsorg and a baby girl born since his death, Nov. 29, 1918, a father, W. H. Ohnsorg, mother, Ida May Ohnsorg, and a sister, Mrs. Stuart Strathy McNair. He was a member of the American Institute of Mining Engineers and of the Florida Phosphate Miners' Association. Lieutenant Edward Hale Perry At the height of the first great German'offensive -of'the Spring of 1918, Edward Hale Perry, of Boston, First Lieutenant, Company D, Sixth Regiment Engineers, U. S. Army, was killed on March 30, near War fusee—Aban-court, Picardy, France, while defending the Boisdes Tailloux against the terrific plunge aimed at Amiens. Lieutenant Perry was born in Boston, Jan. 23, 1887, the son of Georgianna W. and the late Charles F. Perry. After completion of his college preparatory course, he travelled for a year in South America and Europe before entering Harvard with the class of 1910. It might have been regarded as the natural thing for Perry, upon graduation, to choose a path that would lead to a business or professional career at home, but there were in his character a solidity, a horror of sham, a contempt for the "soft" things, and a love-of the open which caused him to be attracted to a life of stern and sturdy reality. Accordingly, he entered the graduate mining school at Harvard, and received the degree of Mining Engineer in 1913. In the meantime, two summers spent in Western mining camps had at-

Jan 1, 1920

By M. T. Simnad, G. Derge, I. George

Measurements of current efficiency on iron-silicate slags in iron crucibles showed that conduction is about 10 pct ionic in slags with less than 10 pct silica and about 90 pct ionic in slags with more than 34 pct silica, increasing linearly in the intermediate range. The balance of the conduction is electronic in character. Silicate ions are discharged at the anode with the evolution of gaseous oxygen. Transport experiments show that the ionic current is carried almost entirely by ferrous ions, which may be assigned a transport number of one. THERE has been increased evidence in recent years that the constitution of liquid-oxide systems (slags) is ionic.1-3 The principal studies designed to establish the structure of liquid slags have been by electrochemical methods', " and conductivity measurements1,6,7 which also have indicated the presence of semiconduction in several silicate systems1,4-0 and in pure iron oxide.' It is well known that many slag-forming metallic oxides have an ionic lattice type in the solid state, and their properties are determined to a large extent by the lattice defects and ion sizes. As Richardson8 as pointed out, the detailed models of liquid slags cannot be found on thermodynamic data only but "must rest on a proper foundation of compatible structural and thermodynamic knowledge, combined by statistical mechanics." A careful thermodynamic study of the iron-silicate slags has been carried out by Schuhmann with Ensio9 and with Michal.10 They obtained experimental data relating equilibrium CO2: CO ratios to slag composition and made thermodynamic calculations of the activities of FeO and SiO, and of the partial molal heats of solution of FeO and SiO2 in the slags. It was found that the activity-composition relationships deviate considerably from those to be expected from an ideal binary solution of FeO and SiO2. However, the partial molal heat of solution of FeO into the slags was estimated to be zero. Their experimental results were correlated with the constitution diagram for FeO-SiO2 of Bowen and Schairer,11 with the results of Darken and Gurry" on the Fe-O system, and with the work of Darken"' on the Fe-Si-O system. All these studies were found to be consistent with one another. The variation of the mechanism of conduction with composition in the liquid iron-oxide-silica system in the range from pure iron oxide to silica saturation (42 pct SiO2) in iron crucibles was reported in a preliminary note." The current efficiency, or conformance to Faraday's law, showed some ionic conductance at all compositions, the proportion increasing with the concentration of silica. The current-efficiency experiments since have been extended. Furthermore, transport-number measurements have been completed in silica-saturated iron silicates to determine the nature of the conducting ions. Experimental Current Efficiency in Liquid Iron Oxide and Iron Silicates using Iron Anodes: This study was carried out by passing direct current through slags in the range from pure iron oxide to iron oxide saturated with silica (42 pct silica), using pure iron rods as anodes and the iron container as the cathode. A copper coulometer was included in the circuit to indicate the quantity of current passed during electrolysis. Assuming that the cation involved is Fe-+, the theoretical quantity of iron lost from the anode according to Faraday's law may be calculated and when compared with the actual loss observed, gives an indication of the extent to which Faraday's law has been obeyed. It also gives an indication of the presence and extent of ionic conduction in the melt. Preparation of the Slags: About 100 g of chemically pure Fe,O, powder is placed in an iron pot which is heated by induction until the contents liquefy. In this way, FeO is produced according to the reaction Fe2O3 + Fe = 3 FeO. More Fe2O3 or SiO, powder is added and, when a sufficient quantity of molten slag is obtained, the induction unit is turned off, the pot withdrawn, and the molten slag poured on to an iron plate. Homogenization and Electrolysis of the Slag: Apparatus—After considerable development, the setup illustrated in Fig. 1 proved to be quite satisfactory. A is an Armco iron cylinder, 1 in. ID and 1/8 in. wall, consisting of three sections placed one on top of the other. The bottom section is a pot about 5 in. long with a small hole drilled in its bottom to allow withdrawal of gases during evacuation of the apparatus. The middle section is 6 in. long and consists of a pot which serves as the slag container, while the top section is a hollow-cylinder continuation of the slag-container pot. The height of this latter section is about 5 in., giving an overall length of approximately 16 in. The iron cylinder is constructed in this way for ease of fabrication, the individual sections becoming welded together after the

Jan 1, 1955

By Elmars Ence, Harold Margolin

The titanium-aluminum system has been investigated in the composition region 0 to 34 pct Al in the temperature range 800" to 1450°C. The phases encountered in this region were: a,ß, TiAl3, The reactions observed are as follows: 13 ; L - 6T. A1, 0 (15 pct Al) + 6 (18 pct Al) - yTi Al (16.5 pct Al) at -1170°C andP (7 pctpct Al) + y (9.2 pet Al) - ah(9 pct Al) at - 1060°C. A eutectoid reaction: y — a +d belm 700°C is postulated. THE Ti-A1 system has been the sub.ect of a number of investigations. Several of these1-3 have indicated extensive solubility of A1 in both a and ß titanium. Ence and Margolin, as a result of work on the Ti-A1-0 system:'5 have shown that the a solubility ofalumi-num is considerably restricted, and found that a compound, Ti2A1 existed in the region formerly designated as Q a This structure was identified as hexagonal with c/a = 0.803. Pietrokowsky confirmed the existence of this phase7 and pointed out that the structure was isomorphous with Ti3Sn.8 Although the existence of Ti,A1 has been confirmed by others,9-12 there has been considerable disagreement regarding the composition and mode of formation. A detailed reinvestigation of the Ti-A1 system has been published by Sagel et al.13 The tentative diagram indicated two phases, a, and e, occurring in the former all a region. The a, phase has the same structure as Ti2A1 and was indicated as having a broad region of solubility. Epsilon, a tetragonal phase, was shown to form within the a, solubility region. AS a result of unpublished work,14 Ence and Mugy3 olin disagreed with the interpretation of Sage1 et al., although some common features existed. The present study was conducted in an attempt to clarify prevailing uncertainties. EXPERIMENTAL PROCEDURE Alloy Preparation—Alloys were prepared from iodide titanium (99.9 pct Ti with less than 0.01 pct Zr) or Bureau of Mines electrolytic titanium (BHN-73) and high purity aluminum (99.99 pct). Alloys were arc-melted in argon or helium atmosphere as 15-g buttons in the composition range up to 34 pct Al. Depending on need, alloys were made in increments varying from 0.25 to 2 pct Al. Up to five 15-g buttons of some compositions were made. Weight losses during melting did not exceed about 1 pct of the charge and chemical analysis revealed that both titanium and aluminum were evaporated. In general, nominal and analyzed compositions agreed within 0.5 pct and therefore nominal compositions were used in plotting the data. Unavoidably, some overlap of composition occurred, particularly where small increments of A1 were used. The small increments were primarily used to obtain alloys which would fall into the narrow a -, r region and this purpose was achieved. In general, the data obtained from Bureau of Mines base titanium and iodide titanium alloys were in agreement. Forging—Both as-cast and forged samples were employed. Samples were heated for hand forging by an oxygen-hydrogen torch to the region 1200" to 1300°C. A titanium anvil and cover plate were used to prevent any iron pick-up and consequent formation of a low melting point compound. Frequent reheating kept the temperature in the desired range. Under these conditions, alloys containing up to 15.5 pct could be successfully forged. To check on the depth of contamination, forged alloys were heated slightlybelow the ß transformation temperature. Metal was removed to a depth below the contaminated surface so revealed, and the subsequent results obtained from these samples agreed closely with those secured from as-cast material. Heat Treatment—Prior to heat treatment, all alloys were vacuum annealed to remove hydrogen. Samples

Jan 1, 1962

The paper relates to the laboratory and pilot plant studies that have been carried out by Sherritt Gordon Mines Ltd., Metallurgical Research Div., in developing the ammonia pressure leach process for extracting Cu, Ni, Co, and S from high grade Ni concentrate produced from Lynn Lake ores and describes in some detail the chemistry of the process. In the leaching stage air, ammonia, and sulphide minerals react in a sequence of inter-related steps to produce soluble amines of Ni, Cu, and Co in a solution containing sulphate, thiosulphate, polythionate, and sulphamate ions and a controlled amount of free ammonia, the iron and other components of the concentrate remaining as an insoluble residue which is separated from the leach solution by filtration. The pregnant solution produced in leaching is further treated by boiling to precipitate and remove Cu as cuprous sulphide, leaving a copper-free solution with a composition suitable for subsequent precipitation of Ni and Cu by H,

Jan 3, 1955

By James E. Lawver

A SURVEY of Minerals Beneficiation Div. membership indicated genuine interest in automatic process control, but revealed that the average mill is operating with a minimum of self-regulating devices. Apparently, the mill operators are content to continue without controls until the practicality of self-regulating devices is more generally accepted, or, in the opinion of the writer, until automatic controls become a necessity to meet economic demands of product quality and cost. Both to stimulate interest in control, and to solicit publication of technical know-how by members and equipment manufacturers, this paper presents a cross section of control problems in two general categories: (a) Control problems that can usually be solved by reference to the literature, i.e. controls that have proven successful in the mineral or chemical industries; (b) Problems that are troublesome and frequently unsolved due to unavoidable adverse conditions in the mill circuit to be controlled.

Jan 10, 1953

By Clemens Jones

The difficulties attending the reduction of ferric sulphate in the determination of metallic iron by the method of Marguerite, are often serious, and affect time, patience and accuracy. They depend upon the condition and purity of the zinc used, the state of saturation of the solution, acidity, and temperature. D. J. Caruegie (Chem. News, lvii., No. 1481), says that ferric solutions are instantaneously reduced by the use of zinc-dust. But there are obvious objections to its employment in quantitative work. Dr.

Jan 1, 1889

By S. Isserow

RECENTLY, a description of the wartime work in this laboratory on the U-Si phase diagram was published. This diagram was available earlier in the open literature; as were Zachariasen's crystal structure identifications for the compounds in the system. The uranium end of the phase diagram is shown in Fig. 1. The most recent work on this system has emphasized the peritectoid E phase, of particular interest for a number of reasons. The early work provided evidence of this phase's resistance to corrosion in water and of its slight ductility. Further information on these properties has been obtained here. Work elsewhere4 has provided evidence of stability under irradiation. This body-centered-tetragonal phase is relatively isotropic compared to the more usually applied a or ? uranium phases. Unlike the other compounds in this system, it contains no Si-Si covalent bonds.3 In addition, consideration on the basis of Pauling's concepts leads to the conclusion that in the E phase, uranium has a higher valence than in any of the other phases. Definition of the composition of the ? phase has been of prime concern in the study of this alloy. Evidence is presented below that its silicon content is slightly higher than that of stoichiometric U8Si, the composition frequently assigned this phase on the basis of Zachariasen's identification. This work on the composition required careful attention to the method of dissolving the alloy for analysis, since apparently low silicon contents could be found under certain conditions, see Appendix. Preparation: Melting, Casting, and Heat Treatment—Almost all the samples were from castings with a diameter of 13/4 or 2 in. and about 1 ft long, weighing 10 to 15 lb. The U-Si charge was melted by heating to about 1650°C in an induction heated vacuum furnace. Beryllia crucibles were used at first, but were replaced by zirconia-washed graphite as the technique of keeping the carbon content low enough (about 500 ppm) was mastered. The alloy was bottom-poured at about 1650°C into graphite molds. A few small buttons, weighing no more than 50 g, were prepared in a small arc melting unit.' Since cast material has a preponderance of uranium and U8Si2, heat treatment is necessary to ob-tain the ? phase by the solid-solid peritectoid reaetion. Once obtained, the ? phase is stable to room temperature, obviating the need for speeial attention to the method of cooling after epsilonization, see Fig. 1. It was found desirable to epsilonize at 800°C for a week. For some purposes, in which residual uranium and/or U8Si2 are tolerable, shorter periods may be adequate. The temperature of 800°C is not critical, since essentially the same results were obtained from 785° to 825°C. Further departure from this epsilonization range is inadvisable.

Jan 1, 1958

By Oswald J. Heinrich

(Read at the Amenia Meeting, October, 1877.) THE deposit of rock salt along the shores of Lake Huron, in Canada, has been brought before the public during the last six months, in consequence of the developments made by the diamond drill at Goderich. It is likely to be of more than common interest in the future, since now actual operations have been commenced to exploit the deposit and work it by regular mining. The methods of mining rock salt being but little known in this country, it may be of interest to make a few general remarks in regard to them before entering, upon the description of this new mining enterprise. According to the conditions under which salt is found in nature, various methods have been resorted to, in course of time, to make it available for the human race. They consist in : A. Natural or solar evaporation. B. Artificial evaporation, either exclusively or in connection with the former. C. Mining the rock salt in its natural state, and converting it to a marketable product, if need be, by simply pulverizing it. Without going into the details of the various methods of making salt available in an economical point of view, dependent on its degree of purity, or on various local influences, we cannot refrain from. alluding to the general principles which influence the mining and manufacturing of salt in countries where they have been carried on for hundreds of years. ECONOMICAL CONDITIONS FOR SUCCESS. Salt being one of the articles of prime necessity, and one universally distributed throughout nature, it must always be sold at a comparatively low price. It would even be quoted in the market at prices far below those now ruling, if it were not for the high duties generally imposed upon it, for purposes of state revenues. But looking closer into the subject, it will be found that this duty is probably one of the least oppressive, although in some countries it exceeds sixfold the cost of profitable production. To produce the article at the lowest possible cost requires, therefore, a

Jan 1, 1878

By AIME AIME

CHARLES A. CHASE, manager of the Shenandoah-Dives Syndicate, operating the Shenandoah Mines in southwestern Colorado, reviewed the current work at that property at a recent meeting of the Colorado Section, in Denver. This operation is a new one, having been in effect only two years, but the properties that were consolidated by Mr. Chase had had certain production in earlier years, since when they had: been inactive. These properties are located. in the high mountains of the San Juan section in Colorado, and although they had had a substantial production of ores of good grade in the upper levels, the project as a whole involved the bold undertaking of driving through the mountain, starting on the Mayflower claim on the Arrastre Gulch side and passing through the Mayflower, Slide, Terrible, North Star, Dives and Shenandoah No. 3 claims. This is a distance of over 8,000 ft. which is known to be mineralized, and the main operating tunnel was started at an elevation of approximately 11,000 ft. The main exploration work has already extended in nearly 4,200 ft. and the present mining production of nearly 550 tons daily is being secured while the main exploration work is being continued. The main heading is now within the North Star claim and the plan of operations involves continuing ahead for a few hundred feet and then starting an upraise which will he 2,200 ft. high and which will connect with the old workings of the North Star mine. The plan of ruining then will he to drive levels along the vein in both, directions to daylight and retreat downward, taking out all the ore and abandoning, the workings after the ore is removed. In this way one level after another progressing downward will be abandoned. The raise will be of two compartments, one of which will carry the 8-ton skip and the other the counterweight and manway. So far the ore has been broken over an average width of more than 11 ft., with an output of 39 tons per machine shift.

Jan 1, 1932

By R. L. Huntington, Frank P. Vance, George F. Russell, Robert Thompson

With the advent of higher pressures in the operation of natural-gas transmission lines, the removal of water vapor from the gas has become increasingly important in order to prevent condensation or formation of gas hydrate from slowing down or stopping the flow of gas. Intelligent design of these dehydration or gas-drying plants has been hampered through the Iack of experimental data on the water vapor content of natural gas at elevated pressures. In view of this need, this present investigation was sponsored by the Southern Natural Gas Co. in the Chemical Engineering laboratories at the University of Oklahoma Research Institute. Experimental results were obtained on the water-vapor content of natural gas up to 2000 lb. per sq. in. at atmospheric temperatures. The water content at 2000 lb. is approximately two thirds as much as it is at 1000 Ib. Deviations from the ideal gas laws vary directly with pressure and indirectly with temperature. Introduction The removal of water vapor from natural gas is an important operation in connection with the production and transportation of this commodity because: I. Liquid water accelerates internal corrosion of a pipe line. 2. Accumulation of water at low points in a pipe line reduces markedly its capacity. 3. Gas hydrates, icy snowlike growths, form readily under high pressure in the presence of the lower hydrocarbons and water, often plugging up the pipe line. In order to design dehydration plants for stripping the gas of its water content, it is essential that the engineer. have a knowledge of the saturated or equilibrium water-vapor content of the gas to be processed. With the gradual increase of operating pressures around gas-producing wells and pipe lines, it was observed that the quantity of water recovered from dehydration plants or condensed in colder lines was considerably greater than had been expected from calculated contents, based on vapor-pressure data taken from steam tables. This observation prompted a number of investigators, for instance, Laulhere,3 Dea-ton,l and Hammerschmidt2 to carry out experimental work at pressures up to 600 lb. per sq. in. in order to determine quantitatively the water content of various gases. Sage, Lacey, et al.4,5 have recognized more recently the need for such data at higher pressures, but their work was done at temperatures of 100ºF, and higher. Since hydrate formation usually, if not entirely, occurs at temperatures below 100ºF., the present investigation was confined to the . lower temperature range at pressures from 600 to 2000 lb. per sq. in. gauge.

Jan 1, 1945

By M. K. Seguin

The study described in this paper is first centered on the determination of the physical properties (gravimetric, magnetic, electrical, and electromagnetic) o f metamorphosed iron ores of the Carol Lake-Labrador City District. Different geophysical surveys available in the Carol Lake-Wabush area were interpreted quantitatively and the dimensions, attitude, and tonnage of the ore bodies investigated were determined. A geophysical-statistical study was undertaken which permitted the determination of the grade of iron, magnetite, and, subsequently, specularite in the ore bodies. A discussion of the theory and logical progression of the study and the application of the results to actual geophysical data is presented. The conclusions, which are of real significance from the economic standpoint, may be predicted from the data obtained from geophysical surveys before any diamond drilling is undertaken. An integrated interpretation of this type is useful in planning future exploration work and selecting the most favorable geological structures. It also serves as a guide to minimize and determine tonnage drilling patterns. The general conclusion that a restricted range of residual gravity and magnetic anomalies are a key to exploration is valid. Indeed large depths to the top of deposits are absent since all the ore bodies are overturned synclinal structures with tops located close to the surface. Certain irregular geometries do occur but they are not common and the alignment of the iron ore bodies is sub parallel so that magnetic anomalies are evenly reduced in the earth's magnetic field vector.

Jan 1, 1975