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By L. Weaver

THE Tennessee Copper Co.'s mines are in the southeast corner of the state of Tennessee, Polk Co., in the well-known Ducktown copper basin. Their new circular production shaft will eventually be the only ore hoisting shaft, and is located for handling ore from Boyd, Calloway, Mary, and Cherokee mines. A circular, rather than a rectangular, shaft was decided upon because: 1-The circular shaft section is stronger when lined with concrete. Reinforcing steel was not required, thus reducing lining cost by one- quarter. 2-Water sealing was desired; it was thought it could best be done with a concrete lining followed by pressure grouting to eliminate water seeps. 3-The shaft labor saving equipment could best be used in a large opening, so the round section was made for economy, sinking, mucking, concreting and water sealing. Less shaft steel is used than could have been possible with steel sets. There are no posts required; center beams and Tee plate assembly placed at 10 ft hold the 100 lb steel guide rails.

Jan 1, 1950

By A. C. Rubel

WHAT does management expect of W and from an engineer? First and foremost, it expects that he should become, and therefore should fit himself in every way to be, a part of management so that he may assume as much and as many of the responsibilities of management as his ability and the opportunities of the job permit. Let me make clear at the start that the profession of pure, technical engineering offers but limited opportunities at the top levels because of the inherent organization of engineering work. The line of succession to top jobs may be likened to a cone with a broad base and an extremely sharp point. Consider any oil company, large or small, or any operating function of that company, and you will find few top engineering jobs in the organization. This is true by the nature of the work handled. There will be a few district engineers depending on the spread of operations, a chief petroleum and production engineer, perhaps a few research engineers, possibly some technical executive assistants, and that is usually all. The road to these jobs is a long one and the competition is tough. The larger the organization the greater the opportunity, but always the ratio of engineers to top engineering jobs is only a small one.

Jan 1, 1947

THE metal iron has physical arid chemical properties which are some- what different from those of steels, but a knowledge of the pure metal is a useful starting point in studying the behavior of steels. Solid iron exists in two different crystalline forms, called alpha (a) and gamma (?) iron the former being the ordinary form at room temperature. When heated above the "A2 point," 769 C (1416 F), the metal becomes nonmagnetic, and at the "A3 point," 911 C (1672 F), it undergoes a change in crystalline form to become gamma iron. 111 the range 769 to 911 C, it is sometimes called beta (ß) iron to distinguish it from the magnetic alpha, but the two are identical in crystal structure. When gamma iron is further heated to 1392 C (2538 F), it changes into delta (d) iron, which is identical with beta or nonmagnetic alpha iron. Pure iron melts (in an inert atmosphere) at 1536 C (2797 F); the melting point is generally lowered by alloys or impurities. PHYSICAL AND THERMAL PROPERTIES OF IRON Many of the properties of iron undergo abrupt changes at the transition temperatures.1 For example, in heating through the A3 point, a sudden shrinkage in volume occurs. Similarly, melting is attended by sharp physical changes such as an increase in volume. Table 16-1 contains a summary of the measured physical properties of pure iron at several temperatures. Usually the properties change smoothly with the range of stability of a given form, but this is not always true. For ex- ample, the specific heat reaches a sharp maximum at the A2 point al- though no transformation occurs. (See Fig. 14-1.) Solvent Powers of Liquid Iron. Liquid iron is capable of dissolving most of the other metals and many nonmetallic elements as well. Of the metals that are liquid at the melting point of iron, only lead, silver, and bismuth refuse to dissolve to an appreciable extent. Table 16-2 contains a list of the common elements classified with respect to their solubility in liquid iron. Those which are very soluble or practically insoluble require no further discussion, but several of the nonmetals that are gases and exhibit limited solubility are of considerable importance to us and merit more detailed consideration.

Jan 1, 1964

By Verne D. Johnston

ALTHOUGH the stocks of Lake Superior iron ore on dock or at furnaces at the beginning of the year were about 6,000,000 tons less than at the beginning of 1938, the steel industry was operating at only 52 1/2 per cent of capacity and continued at approximately this rate to about Aug. 1. Consequently the iron mines in the Lake Superior district during the winter and spring period were almost all on a curtailed production basis, governed mostly by the needs of the communities rather than by anticipation of ore demands. Many of these properties gave extra employment by prosecuting heavy strip- ping programs, and the underground mines by shaft sinking and rock development. All underground mines re- turned to full operation in September, mostly two-shift, five days per week. A few operated the sixth day. The ship- ping schedules were increased so that the actual delivery for the year exceeded early expectations by about 20 per cent. Final Lake shipments were slightly in excess of 45,000,000 gross tons.

Jan 1, 1940

By M. E. Wadsworth, T. D. Chatwin

The kinetics of sulfidization of hematite (Fe203) by H2S gas at various partial pressures have been determined over the temperature range of 170° to 500°C. The process was controlled by thin films of pyrite (FeS2) and troilite (FeS) which were protective and formed diffusional layers. At higher temperatures the thermodynamic drive to form FeS2 decreased, and consequently the rate of formation of FeS, decreased. Conditions for the development of thin layers of FeSz consisting of 10 to 100 atomic diameters are presented. Laboratory flotation results on synethetic ores indicate floatability identical to that of pyrite of normal xanthate flotation. The prospect of high-temperature sulfidization of metal oxides using H2S, S, or other sulfur bearing compounds is intriguing as a potential activation process for flotation since the thermodynamics are very favorable for a large number of systems. If the kinetic parameters are sufficiently well understood it may be possible to provide surface sulfide layers a few angstroms thick, thus imparting normal sulfide floatability characteristics to the oxide. For thin layers the total sulfur pick-up would be small except for very high surface area materials but in most cases this sulfur could be readily removed by roasting if necessary. The general reactions for the sul-fidization of metal oxide MxO, to a metal sulfide MpSq using H2S may be written for the three conditions py > xq; py < xq; and py = xq: A large thermodynamic advantage is obtained in many systems because of the relatively large negative free energy of formation of H,O compared to H,S. For the temperature range 2S° to 1500°C &apos; where AFOis the standard free energy and T is absolute temperature. As is evident from Eqs. 4 and 5, the free energy of formation of H ,0 is approximately 35 to 37 kilocalories per mole greater than that for H,S over broad variations of temperature. For oxide-sulfide systems as outlined above, sulfidization may be expected to occur for the conditions: Groups I and 111: that is, if the terms on the right are more negative than those on the left the reaction is expected to occur thermodynamically. The value hFg,(,) is included in Eq. 6 since hFLzs is based upon gaseous S2 rather than the normal reference state, orthorhombic sulfur. The

Jan 1, 1969

By C. J. Ramsburg

The construction and operation of by product coke-oven plants in America are essential to strong national defense and of the greatest importance to many widely diversified undertakings as well as to safety and health. Carbonization Process Coal used under a boiler or in a locomotive is consumed by combustion. Coal used in a by-product oven is distilled or carbonized, meaning that heat is applied to the coal, out of contact with air, causing a distillation that removes the volatile matter in the coal in the form of gas and vapor, leaving coke as a final product. From the gas and vapor distilled from the coal, many valuable substances can be secured, known as by-products. Hence the name "by-product oven." The simplest example of this principle can be shown by means of an ordinary clay pipe. If powdered coal is placed in the bowl of the pipe, the opening of the bowl is plugged with clay, and the bowl placed in a flame, the bowl will become hot, transferring the heat through the wall of the bowl to the coal within. When this coal attains a temperature of about 750°F., gas will begin to pour out of the pipe stem, and this gas may be lighted. A black liquid also will exude from the stem of the pipe, This is tar mixed with certain other products. What remains in the bowl after distillation is coke. A coke oven corresponds to the bowl of the pipe. A modern oven of the latest type is a refractory brick chamber approximately 42 ft. long and 14 ft. high, averaging 18 in. in width. The oven is filled with coal through closable charging holes in the oven top. Each end of the oven consists entirely of a self-sealing door, the removal of which permits the finished coke to be discharged by means of a power-operated pusher machine. The ovens are built in batteries, and the heating is effected by gas burned in vertical flues in the oven walls, each set of flues heating the walls of two adjacent ovens. Such ovens carbonize a charge of approximately 18 tons of coal in 18 hr., or have a daily throughput of 24 tons per oven, producing about 17 tons of coke. In times of need, the output may be increased by raising the temperature of flues, thus shortening the coking time. There is one great essential difference in principle between distillation in a clay pipe and in a coke oven. In the 18-in. oven, the distillation proceeds from two parallel walls held at a high temperature (over zooo°F.) and instead of all the coal being heated at once, the distillation is a progressive one creeping inward. The average travel of this heating is 35 in. per hour from each vertical wall, and as the volatile products are formed progressively they must push away from the interior toward the wall through the previously formed hot coke, then up the walls and Over the top of the coal charge, finally escaping through the outlet pipe. This results in a cracking of the components into many different and valuable substances not formed when the carbonizing temperature is low.

Jan 1, 1942

By C. J. Ramsburg

THE construction and operation of by-product coke-oven plants in America are essential to strong national defense and of the greatest importance to many widely diversified undertakings as well as to safety and health. CARBONIZATION PROCESS Coal used under a boiler or in a locomotive is consumed by combustion. Coal used in a by-product oven is distilled or carbonized, meaning that heat is applied to the coal, out of contact with air, causing a distillation that removes the volatile matter in the coal in the form of gas and vapor, leaving coke as a final product. From the gas and vapor distilled from the coal, many valuable substances can be secured, known as by-products. Hence the name "by-product oven." The simplest example of this principle can be shown by means of an ordinary clay pipe. If powdered coal is placed in the bowl of the pipe, the opening of the bowl is plugged with clay, and the bowl placed in a flame, the bowl will become hot, transferring the heat through the wall of the bowl to the coal within. When this coal attains a temperature of about 950°F., gas will begin to pour out of the pipe stem, and this gas may be lighted. A black liquid also will exude from the stem of the pipe. This is tar mixed with certain other products. What remains in the bowl after distillation is coke. A coke oven corresponds to the bowl of the pipe. A modern oven of the latest type is a refractory brick chamber approximately 42 ft. long and 14 ft. high, averaging 18 in. in width. The oven is filled with coal through closable charging holes in the oven top. Each end of the oven consists entirely of a self-sealing door, the removal of which permits the finished coke to be discharged by means of a power-operated pusher machine. The ovens are built in batteries, and the heating is effected by gas burned in vertical flues in the oven walls, each set of flues heating the walls of two adjacent ovens. Such ovens carbonize a charge of approximately 18 tons of coal in 18 hr., or have a daily throughput of 24 tons per oven, producing about I 7 tons of coke. In times of need, the output may be increased by raising the temperature of flues, thus shortening the coking time. There is one great essential difference in principle between distillation in a clay pipe and in a coke oven. In the 18-in. oven, the distillation proceeds from two parallel walls held at a high temperature (over 2000°F.) and instead of all the coal being heated at once, the distillation is a progressive one creeping inward. The average travel of this heating is 1/2 in. per hour from each vertical wall, and as the volatile products are formed progressively they must push away from the interior toward the wall through the previously formed hot coke, then up the walls and over the top of the coal charge, finally escaping through the outlet pipe. This results in a cracking of the components into many different and valuable substances not formed when the carbonizing temperature is low.

Jan 1, 1942

By C. J. Ramsburg

The construction and operation of by product coke-oven plants in America are essential to strong national defense and of the greatest importance to many widely diversified undertakings as well as to safety and health. Carbonization Process Coal used under a boiler or in a locomotive is consumed by combustion. Coal used in a by-product oven is distilled or carbonized, meaning that heat is applied to the coal, out of contact with air, causing a distillation that removes the volatile matter in the coal in the form of gas and vapor, leaving coke as a final product. From the gas and vapor distilled from the coal, many valuable substances can be secured, known as by-products. Hence the name "by-product oven." The simplest example of this principle can be shown by means of an ordinary clay pipe. If powdered coal is placed in the bowl of the pipe, the opening of the bowl is plugged with clay, and the bowl placed in a flame, the bowl will become hot, transferring the heat through the wall of the bowl to the coal within. When this coal attains a temperature of about 750°F., gas will begin to pour out of the pipe stem, and this gas may be lighted. A black liquid also will exude from the stem of the pipe, This is tar mixed with certain other products. What remains in the bowl after distillation is coke. A coke oven corresponds to the bowl of the pipe. A modern oven of the latest type is a refractory brick chamber approximately 42 ft. long and 14 ft. high, averaging 18 in. in width. The oven is filled with coal through closable charging holes in the oven top. Each end of the oven consists entirely of a self-sealing door, the removal of which permits the finished coke to be discharged by means of a power-operated pusher machine. The ovens are built in batteries, and the heating is effected by gas burned in vertical flues in the oven walls, each set of flues heating the walls of two adjacent ovens. Such ovens carbonize a charge of approximately 18 tons of coal in 18 hr., or have a daily throughput of 24 tons per oven, producing about 17 tons of coke. In times of need, the output may be increased by raising the temperature of flues, thus shortening the coking time. There is one great essential difference in principle between distillation in a clay pipe and in a coke oven. In the 18-in. oven, the distillation proceeds from two parallel walls held at a high temperature (over zooo°F.) and instead of all the coal being heated at once, the distillation is a progressive one creeping inward. The average travel of this heating is 35 in. per hour from each vertical wall, and as the volatile products are formed progressively they must push away from the interior toward the wall through the previously formed hot coke, then up the walls and Over the top of the coal charge, finally escaping through the outlet pipe. This results in a cracking of the components into many different and valuable substances not formed when the carbonizing temperature is low.

Jan 1, 1942

By C. H. Herty

The reactions that occur in the basic open-hearth process are complicated and are subject to many different factors such as temperature, slag composition and rate of boiling of the bath. It is difficult, therefore, to present an extended theoretical discussion of open-hearth operations without confusing the theory of the process with the application of the theory. This paper attempts to present some of the theory of the open-hearth process without mentioning theory at any point, simply giving some of the practical applications of results founded both on theory and practice and on experimental work both in small and large furnaces. It is hoped that an answer to a number of questions commonly asked by the open-hearth operator may be found in this paper. Discussion of the subject matter is taken up more or less in the order in which a heat ie worked, beginning with the oxidation of the scrap charged, sulfur absorption by the scrap, calcination of the limestone, and extending into the pig iron for the charge, the slags formed during the process, and some of the phenomena occurring in deoxidation of the steel and in its action in the molds. Oxidation of Scbap When scrap is charged into a furnace it immediately begins to oxidize, Oxidation is carried out by.three reactions: Fe + H20 + FeO + Hz (absorbs heat) (1) Fe + C02 + FeO + CO (absorbs heat) (2: Fe+ ½O2 + FeO (gives off heat) (3: The product of oxidation contains some Fe3O4, but FeO usually predominates on account of the iron present in close contact with the scale formed For a given type of scrap the amount of oxidation is controlled by thc fuel and by the excess air being carried in the furnace, the temperature 01 the furnace, and the length of time that the scrap is in contact with the furnace gases. In general, less oxidation occurs when the furnace is rur hot so that the scrap melts rapidly. More important in operation thar the two variables atmosphere and temperature, is the type of scrap being

Jan 1, 1929

By Malcolm J. McPherson, Michael Hood

Sunnyside Mines, owned and operated by the Kaiser Steel Corporation, are situated near the city of Price, Utah. The complex comprises three adjacent mines, named simply Nos. 1, 2 and 3, all connected underground. Two seams, the upper and lower Sunnyside have been worked. These dip at about 10 percent to the north-east. The surface cover is variable due to the mountainous nature of the topography. The Sunnyside upper seam varies from 5 1/2 ft (1.7m) to 9 ft (2.7m) In thickness whilst the lower seam remains at about 6ft (1.8m). The separation between the two seams has ranged from 7 to 45 ft over the mined area (2 to 14m). Longwall mining has been practiced at Sunnyside for over 20 years due to difficulties of roof control encountered when using the roan and pillar system. Number 3 mine is bounded on the north and south sides by mines Number 1 and 2 respectively. Whilst current production is concentrated into Number 1 mine, much of the future of the complex lies in the further development of deeper reserves in Number 3 mine. Workings in this latter mine were curtailed in 1978 due to difficulties in ventilation. Present developments are ventilated partially from the neighboring Number 2 mine where no workings are in progress. The layout of Number 3 mine is illustrated on the schematic Figure 1. Trunk airways extend down dip from the surface at No. 2 Canyon and the Water Canyon for a distance of some 9,600 ft. (2930m). The area between the two sets of trunk airways has been worked extensively in both seams as have the corresponding reserves on either side in the connected adjacent mines. At the present time exhausting fans are sited at the top of a shallow shaft in No. 2 Canyon and an 8 ft (2.4m) diameter shaft sunk to a depth of 1013 ft (310m) closer to the current developments (Figure 1). The current airflow system, even with an additional 116,000 cfm (55m3/s) entering from No. 2 Mine, is adequate only for the development work now in progress but will be unable to support new longwall faces further downdip. The basic ventilation problem of this mine may be stated quite simply. In a situation where all intake and return airways pass through extensive old workings, a ventilation system design was required that would be effective, efficient and economic for the foreseeable future of the mine. ORGANIZATION OF THE PLANNING PROCEDURE The procedure followed during the study is illustrated on Figure 2. Initial ventilation surveys established the current state of the airflow system and provided the necessary data for setting up a Basic Network File in a computer store. The data in this file was a mathematical model of the ventilation system of the mine. The basic network was analysed by a ventilation network analysis program in order to correlate the measured and computed airflows and to establish the basic network as a true representation of the mine as it stood at the time of the surveys. The network model could then be extended to simulate the future development of the mine and alternative ventilation designs investigated. The remaining sections of the paper outline the work involved in each of these main phases of the planning procedure. VENTILATION SURVEYS Conduct of Surveys Two types of measurements were conducted simultaneously throughout the air-carrying routes of the mine: (i) Airflow measurements were made by anemometer traverse or smoke tube at 221 selected stations. Anemometer traverses were repeated at each station until at least three gave results to within 5 per cent. (ii) Pressure drop measurements were made across ventilation doors, regulators and, wherever possible, across stoppings. Additionally, frictional pressure drops were measured along airways where such pressure drops were significant (above 0.01 inches of water gauge or 2.5 Pa over a 100m distance). The trailing hose method was used to determine these frictional pressure drops. This involved laying out 100m of abrasive resistant plastic tubing (3 mm internal diameter) with a 4 ft. pitot-static tube facing into the airflow at either end and a low range pressure gauge connected into the line. The trailing hose method was preferred to the alternative barometer technique for this study because of (a) the relative ease of access between measuring points and (b) the greater accuracy within individual airways. The anemometers used were Davis Biram Type A/2-3" (30 to 5,000 ft/min) and Airflow Developments AM-5000 digital (50 to 5,000 ft/min). The pressure gauges employed were Dwyer magnehelic instruments. These were preferred to liquid in glass manometers because of their portability and dependability under adverse mining conditions. A checklist of the equipment used in the survey is given in Appendix 1. The instruments were calibrated before and after the surveys in the mine ventilation laboratory at the University of California, Berkeley. The survey occupied two teams, each of three men, for ten working days. The work consisted

Jan 1, 1982

By D. R. Mash

A strong yield point with attendant enhanced mechanical properties was found in commercially pure beryllium under certain conditions of heat treatment. Beryllium specimens also responded to both quench and strain aging treatments. Based on these results, a possible means of obtaining increased normal temperature mechanical properties is suggested. COMMERCIALLY pure beryllium has been found to exhibit the yield point phenomenon and several other aging manifestations under certain conditions of heat treatment. This behavior is not surprising in view of the present accumulation of experience regarding such effects in numerous metals; but in addition to extending this experience to include beryllium, the present study is of interest because aging effects are generally associated with the presence of small amounts of solute elements. The well known lack of tensile ductility in beryllium at normal temperatures is also considered to be due to impurities in some way. In the present investigation, the view was taken that beryllium of commercial purity (greater than 98 pct) should be considered as a dilute alloy and that precipitation phenomena may well exist which could lead to enhanced mechanical properties. In connection with this possibility, published data on the variation of mechanical properties with temperature are of interest. For example, Fig. 1 illustrates the variation of ductility (percentage of elongation) and ultimate strength as a function of temperature for beryllium of various histories.* Although these curves are somewhat schematic in nature, they clearly indicate the possibility that precipitation of an unstable phase and/or aging effects occur during tests in the region 400" to 700°C. The existence of such behavior should be recognized as affecting the properties of the commercial material and perhaps can be employed advantageously. Experimental Method All testing was done at room temperature using a Baldwin universal testing machine. A microformer extensometer was used in conjunction with a micro-former-type stress-strain recorder. All tests were conducted at constant loading rate, the slowest rates being used. This corresponded to 120 lb per min in the 1200 lb full scale range and 300 lb per min in the 6000 lb full scale range. After the rate of loading was set in the elastic range of the material during the early part of the test, no further adjustments were made, allowing the test to proceed at that setting. In the plastic region of the curve above the yield region, strain rates of from 0.002 to 0.006 in. per min were regularly obtained. All experimentation was carried out on specimens machined from the same lot of beryllium, lot No. Y5036BP. Table I shows the chemical analysis as furnished by the supplier, Brush Beryllium Co., as well as the standard specifications to which commercial beryllium is produced. Both 1/4 in. thick hot pressed plate and ½ in. round hot pressed and warm extruded rods were obtained. The history of the material is reported to be as follows: 1—Beryllium metal plates, produced from a standard hot pressed QMV beryllium metal block 4x15x40 in., were cut off and finished machined to 1/4x6x12 in. flat plates. The original hot pressed block was made by hot pressing —200 mesh vacuum cast attri-tioned powder at about 1050°C under vacuum. 2—Beryllium rod was hot pressed and warm extruded. Extrusion billets were machined from the regular hot pressed blocks followed by extrusion at 425°C. The extrusion was done without jacketing, and graphite was used as a lubricant. The rods were then straightened at 720 °C, after which they were annealed at 800°C for 15 min. Both flat tensile specimens and round tensile specimens were tested. The former were machined from the plate stock into standard specimens according to specifications shown in ASTM E8-52T. The nominal cross-section was 0.25x0.500 in. and the gage length was 2 in. The round specimens were

Jan 1, 1956

By Sherwin F. Kelly

THE present lull in engineering activities presents an advantageous moment for inquiring into the position now occupied by geophysics in its various fields of application. The recent over-expansion in all lines of work resulted in an uncritical employment of these methods of exploration which was bound to have its harmful reaction. The pendulum has now swung back, producing a decidedly hypercritical attitude toward the new science that had been recently welcomed so joyfully as the panacea for prospecting troubles. The severe retrenchment in exploration has forced upon us a period of waiting and, it is to be hoped, of profitable contemplation. This can well be employed in trying to pass a reasoned judgment on what position geophysics should occupy in the new geological exploration programs that will inevitably ac- company the looked-for industrial recovery.

Jan 1, 1931

By Oscar Harder

IT is now just a quarter of a century since Fred W. Taylor§(23) pub-lished his classical paper On the Art of Cutting Metals, describing -his researches in which he, in cooperation with Maunsel White, had developed what is essentially the modern method of heat-treating high-speed steels. Regarding this research, Dr. Sauveur, (22) in his address on Steel Wizards, Past and Present, at the annual banquet of the American Society for Steel Treating in Philadelphia in 1920 said, "The discovery of high-speed steel, or if you prefer, of the treatment imparting high-speed properties to certain steels by Taylor and Maunsel White I am inclined to consider as our one epoch-making contribution to the metallurgy of steel." It was at about that same time (1900) that Taylor exhibited high-speed steels, heat-treated by the improved process, at the World&apos;s Exposition in Paris and attracted much attention by showing that the steels would operate at such feeds and speeds that the tips of the tools were visibly red hot. This observation must have started metallurgists to wondering regarding the relative hardness of the various steels at red-heat temperatures. Considerable work has indeed been done in an effort to measure the hardness of high-speed steels and. related materials in the red-heat range, using various methods. . The results, however, have been only partly satisfactory, owing to experimental difficulties. The present investigation had as its immediate inception an address by J. V. Emmons, of the Cleveland Twist Drill Co., to the Columbus Chapter of the American Society for Steel Treating in 1931, in which he deplored the fact that comparatively little was known with regard to the hardness of high-speed steels at elevated temperatures, in spite

Jan 1, 1933

By C. H. Wayman, D. W. Fuerstenau

THE gas phase is one of the indispensible ingredients in flotation operations. Flotation depends on the collision of an air bubble and a mineral particle in a pulp and their ability to remain in contact long enough for adherence to take place. Before it is possible to understand the mechanics of air bubble-mineral particle encounter, it is necessary to learn more about the nature of bubbles themselves before collision with a mineral particle has taken place. To date, little work has been done on air bubbles in flotation systems. In 1945 Fahrenwald1 presented a study of the role of frothers on air bubbles and on aeration in flotation, and recently Wark and Sutherland2 discussed the work of Rosenberg3 in relation to flotation. The research reported in this present article was undertaken to investigate systematically the effect of bubble size and the concentration of certain reagents on the terminal velocity, shape, path, and drag coefficient of single bubbles in distilled water. Most of the work is concerned with the effect of a-terpineol on bubble motion in water, but studies were made with potassium chloride, potassium hydroxide, potassium ethyl xanthate, and potassium amyl xanthate.

Jan 6, 1958

By R. W. Raymond

The idea of obtaining light from incandescent solids is not new; nor is it. new to make such bodies incandescent by holding them in a heating flame. But the successful combination of the right substance and form of the body to be heated with the right kind of flame and the right means of adjustment, has not, to my knowledge, been accomplished heretofore; and it seems to me that the matergas incandescent light of Mr. Otto Fahnehjelm of Sweden, in which these objects appear to have been secured, is destined to become both famous and useful. The first fact upon which this invention is based, is the intense

Jan 1, 1885

By AIME AIME

A MODERN copper reduction works has both a genera1 chemical laboratory for control work and a research laboratory for the study of improvement of present processes and better working-up of by-products. The division of work in the general laboratory would naturally differ in different plants. The following statement to the writer from a chemist in one of the works will give a good idea of the type. of work in the general laboratory :

Jan 1, 1929

By Joseph M. Jacisin

Fatigue tests were conducted on 2017-T4 alumium in alloy in an u1lrcthig.h vacuum of 2 x 10-lo Torr and in air. The vatio of vacuum-to-air faligue life for this ~malerial varied Jrom 3.5:1 at a strain of 2.5 X 1O-3 ill. pegr in. to 8:l at a strum of 3.3 x X ill. per 171. Sotlze pvelivtlinary data were also obtained on the faligue life of the alumirnum alloy in a dvy-nitrogen atmosphere. A dark deposit observed on the fracture surfaces of the aiv-tested specimens was identified as oxides of tr~angarzese and magnesium This observalion, and the close correlalion betaveen results obtained in vaCuum and dry-nitrogen environtments, tend to confirm that air stvongly influences the fatigue mechanism by a covrosion process. THE fatigue life of certain metals is known to increase when the atmospheric pressure is reduced. Gough and Sopwith1-2 postulated that this is due to a joint chemical and mechanical process operating in air at the surface of the metal with oxygen and water vapor playing significant roles. Wadsworth and Hutchings3 observed that aluminum is mainly affected by the presence of water vapor. Very little information is available on the fatigue properties of structural aluminum alloys in a vacuum environment. This report describes work performed on 2017-T4 aluminum alloy in an ultrahigh vacuum (2 x 10-loTorr) and in air. Some preliminary data are also presented on the fatigue life of the alloy in a dry-nitrogen environment. 1) EXPERIMENT 1.1) Test Material. The material tested was commerciaT 2017-T4 aluminum alloy which, in addition to aluminum, has an approximate composition of 4 pct Cu, 1 pct Fe, 0.8 pct Si, 0.5 pct Mg, 0.5 pct Mn, plus smaller amounts of other elements.* Some typical naturally age to a substantially stable condition. Specimens were then machined from these rods and ground to a No. 8 microfinish. In order to minimize variation in material characteristics, specimens were made from rods procured from the same lot. 1.2) Apparatus. The apparatus and test specimen used in the fatigue tests are shown in Fig. 1. The device utilized a single-cantilever beam with rotating-bending loading. Bending stress was applied to the fatigue test specimen by placing a spacer beneath the bearing support, thereby providing a constant deflec-

Jan 1, 1968

By J. Leja, J. H. Schulman

FROTH flotation is usually effected by the addition of a collector agent and a frothing agent to an aqueous suspension of suitably comminuted mineral ores. The action of collectors is to adsorb onto the surfaces of minerals to be separated, sensitizing them to bubble adherence. The action of frothers has, in the past, been accepted as that of froth formation only, brought about by a lowering of the air/water interfacial tension. Substances capable of producing froth are classed1a,b according to their relative capacities for production of froth-volume and froth stability in the simple frother-water system. The purpose of this paper is to show that the surface active agents acting as frothers become effective only when there is a suitable degree of molecular interaction taking place between collector molecules and frother molecules at the air/water and solid/ water interfaces. Further, the discussion will demonstrate that the actual mechanism of adherence of an air bubble to a suitably collector-coated particle is due to the molecular interaction collector-frother. This leads to the formation of a continuous interfacial film of associated molecules, anchored to the mineral by polar groups of the collector, and enveloping the whole bubble. The tenacity of adhesion mineral-to-bubble results from the strength and the visco-elasticity of this mixed film.

Jan 2, 1954

By Curtis L. Graversen, J. H. Hamilton, John C. Nixon, John R. Lewis

RECENTLY there has been much speculation concerning the advantages of using oxygen enriched air or pure oxygen in pyrometallurgical processes. The advantage of using oxygen in the iron blast furnace and elsewhere in ferrous production metallurgy has been given careful consideration and, as a result, several experiments have been tried and a number of papers have recently appeared on this subject.1.2 The use of oxygen in nonferrous smelting likewise poses interesting problems, therefore any experimental data obtained in this area should likewise be of general interest.3 Ashcroft4 in 1933 claimed to have obtained improved results when copper concentrates were roasted in pure oxygen. However, his&apos; paper gives neither data nor experimental details. A few years ago a research program was started in this laboratory which had for its objective the determination of the mechanism of oxidation of metallic sulfides under varying conditions. To date we have studied the oxidation of galena, 5 sphalerite, and chalcocite. It is a well known fact that copper sulfide minerals are oxidized slowly by weathering agents, so that the sulfides of copper which find their way into a tailing pond are gradually changed into watersoluble and acid-soluble compounds. Commercially, the oxidation of copper sulfide minerals is accomplished by roasting them at elevated temperatures in air using a suitable (usually multiple-hearth) roaster. Most copper smelters are equipped with such roasters. In this phase of the study we were especially interested in determining the effect of temperature on: (I) the air oxidation of chalcocite and (2) the oxidation of chalcocite using commercial oxygen. The amount of sulphur removed as sulphur dioxide, the percentages of water-soluble copper, and of acid-soluble copper were determined for the air oxidation tests. In the tests using commercial oxygen, the percentages of sulphur dioxide, water-soluble copper, acid-soluble copper, water-soluble sulphur and acid-soluble sulphur were determined. For these experiments the temperature was varied from 250 to 700°°C. EXPERIMENTAL Preparation of Chalcocite (Cu2S) Natural chalcocite is not pure. Minerals such as bornite, covellite, and chalcopyrite may be present. It was decided, therefore, to prepare some chalcocite in our own laboratory. An intimate mixture of sulphur and finely divided metallic copper in the ratio of 4 g of copper to I g of sulphur was prepared. To this was added a slight excess of

Jan 1, 1948

Division of Geology, State of Tennessee, 401 Seventh Ave, North, Nashville, Tenn. Walter F. Pond, State Geologist A selected list of Bulletins available: Bulletin 1(B), Bibliography of Tennessee geology (1911); 2(A) Outline introduction to mineral resources (1910), 2(D) Marbles (1911); 2(G) Zinc deposits (1910), 16, Red iron ores of east Tennessee (1913), 22, Geology and natural resources of Rutherford County (1920), 24(A) Geology and oil possibilities of parts of Overton, Clay, Pickett and Fentress counties (1920); 24(B) Oil and gas resources of northeastern Sumner County (1920), 26, Mineral resources of Waynesboro Quadrangle (1921); 28, Marble deposits of East Tennessee (1923), 29, Magnetic iron ores of east Tennessee (1923), 31, Zinc deposits of east Tennessee (1923), 33, Tennessee coal fields, 37, Geology and mineral resources of Hardin County, 38, Stratigraphy of the Central Basin (in press), 39, Brown iron ores of the Eastern Highland Rim (in press) From 1911 to 1919, inclusive, volumes were issued annually on The Resources of Tennessee Only a few of the separate papers contained in those volumes are now available Vol. 2 (1911): No 1, Explosions of coal dust in mines, and other papers, No. 4, Lignite and lignitic clays in west Tennessee, and other papers; 5, The growth of knowledge of Tennessee geol¬ogy; 9, The valley and mountain iron ores of east Tennessee, 10, The iron industry of Lawrence and Wayne counties, and other papers; 11, Barite deposits in the Sweetwater district, and other papers, 12, The iron ore deposits in the Tuckalioe district, and another paper Various oil maps (15 to 40 cents each) and traverse maps of counties (25 cents and 31 each) can be had, as well as pertinent U. S topographic maps.

Jan 1, 1933