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By J. T. Price

The study was undertaken to investigate the effect in the charge to a blast furnace of zinc and alkali contents, which tend to form accretions and scaffolds in the upper sections of the furnace. Commercial iron oxide pellets were reduced in a CO:N2, 40:60 gas mixture in a 5-cm by 5-m counter-current reactor (Rist-type apparatus) designed to simulate blast-furnace conditions. Pellets from a commercial magnetite concentrate were prepared in the laboratory with zinc (1% ZnO) and alkali (1% KOH) additions to the concentrate. Reducibility, crushing strength and swelling tests were carried out and the results compared with test data from pellets prepared without additions. The results indicated normal behaviour for those pellets containing zinc, whereas those containing alkali swelled catastrophically under the same reducing conditions.

Jan 1, 1977

By H. C. George

THE Wisconsin. Zinc District, or the Upper Mississippi Lead and Zinc District as it is often called, lies in the southwestern corner of Wisconsin, in, Grant, Iowa and Lafayette Counties, and it includes adjoining parts of Illinois and Iowa. The district is about 70 miles long, north and south, and about 40 miles wide, east and west. It lies wholly within what is geologically known as the non-glaciated area of the Upper Mississippi Valley. HISTORY OF THE DISTRICT The district was first opened up as a lead producer in 1822. From this time until 1860, about 205,000 tons of cog lead (galena) and washed lead (galena) was produced from shallow crevices and openings. From 1860 to 1900, about 74,500 tons was produced, and since that time, from 5000 to 7000 tons has been produced annually. Since-1900, most of the lead concentrate produced has been as a byproduct of the zinc mines. The first zinc ores were mined about 1862. These were the carbonate ores, locally known as " drybone." Very little zinc blende was mined in the district, previous to 1875. The zinc blende ores mined from 1875 to 1900 were mostly of the high-grade, hand-cobbed, sheet-ore class, which usually contained from 45 to 60 per cent. metallic zinc. Such nines as the "Sallie Waters," ? Quinlin," "Lead Mine," "Benton Blende" and "Ida Blende," located near Benton, Wis., were mines which produced ores of this type, during this period. The mines located at Highland, the "Coker Mine" located at Livingston, Wis., and the "Opencut Mine" located at Shullsburg, Wis., were mines that were heavy zinc carbonate producers, previous to 1900.

Jan 12, 1917

By W. R. Hibbard

Pole figures, torque curves, and coercive force have been determined for the following rolled and annealed permanent magnet alloys: Cunife, Cunico, Silmanal, Vicalloy I, Vicalloy II, and Heusler's Alloy. IN the general category of precipitation-type permanent magnet alloys there is a group of ductile alloys, including Cunife, Cunico, Silmanal, Heusler's Alloy and Vicalloy, which can be extensively rolled and annealed to develop a preferred orientation in the crystals of the matrix material. The rolling and annealing textures of Cunifel and Vicalloy' have been previously investigated qualitatively, but no pole figures are available in the literature. In addition, the role of precipitation in these permanent magnet alloys is still somewhat controversial. It

Jan 1, 1957

By O. W. Ellis

RECENTLY there has been a considerable revival of interest in the effects of the various elements commonly added to brass for the purpose of increasing its strength. For many years the work of Guillet2? alone gave reliable information in this regard. Even today his determination's of the coefficients of equivalence of the various elements relative to zinc in brass are those universally employed in industry. This is so because these coefficients have stood the test of time-their substantial correctness has been proved in almost universal practice. It is not our intention to discuss here these coefficients or their use. Rather do we wish to emphasize the need for further systematic studies of the mechanical properties of the ternary systems of copper, zinc, and other individual elements. Since Guillet published the results of his first investigations Millington,16 Smalley33 and Thibaud45 have added somewhat to our information. In general they have confirmed the findings of Guillet, which may be stated in the following rather general terms: 1. The addition of aluminum to the 70:30 and 60:40 brasses progressively increases their hardness and strength and reduces their ductility and resistance to shock. 2. The addition of small amounts of iron to a 60:40 brass improves its strength without affecting its ductility. 3. The addition of small amounts of manganese to a 60:40 brass causes a progressive increase in its strength and reduction in its ductility. A considerable amount of information has been amassed in regard to the effect of nickel on brass (9, 22, 41) which it is unnecessary to refer to here, in view of the scope of this paper.

Jan 1, 1929

By F. L. Ransome

The following paper aims to present in a much condensed form the salient results of a detailed geological study of the Bisbee quadrangle, Arizona, carried on during the latter part of the year 1902. It is essentially an abstract of the final official report which will shortly appear in the series of professional papers of the U. S. Geological Survey, accompanied by maps, sections and illustrations. I. Geography. The Bisbee quadrangle, which includes the Warren mining district, lies in Cochise county in the southeastern part of Arizona. It is inclosed between the meridians 109" 45' and 110" 00' and the parallels 31" 30' and 31" 201, the latter being locally the Mexican boundarg line. The area of the quadrangle is about 170 square miles, and includes the southeastern half of the Mule Mountains, one of the smaller of the isolated ranges characteristic of this part of Arizona. The Mule Mountains, while less markedly linear than the Dragoon, Huachuca, Chiricahua, and other neighboring ranges, have a general NW-SE. trend. They may be considered as extending from the old mining town of Tombstone to the Mexican border, a distance of about 30 miles. On the northwest they are separated by the broad, flat floor of Sulphur Spring Valley from the Chiricahua Range, and on the southeast by the similar broad valley of the Rio San Pedro from the Huachuca Range. The maximum width of the range is about 12 miles, and its greatest elevation attained by Mt. Ballard, west of Bisbee, is 7,400 ft. above sea-level. An index-map, showing the geographical position of the Bisbee quadrangle, is shown in Fig. 1. The town of Bisbee (Fig. 2), with an estimated population of 6,000, is crowded into a few narrow confluent ravines near the

Jan 1, 1904

By D. S. Tannhauser, I. Bransky

Measurements of the electrical conductivity, the thermal electromotive force, and the deviation from stoichiometry by thermogravimetry were made on ferrous oxide (wüstite) single crystals as well as on poly-crystalline samples in the temperature range of -900" to 1330°C. In the region defined by T 2 1000°C and 1.05 5 O/Fe 5 1.10 the electrical conductivity was shown to be proportional to the sixth root of- the oxygen partial pressure and to be linearly dependent on the deviation from stoichiometry. The absolute Seebeck coefficient of single and polycrystalline wüstite was shown to be independent of temperature in the above region and a p to n transition of the Seebeck coefficient was observed at O/Fe = 1.09 in polycrystalline wüstite. Analysis of the results showed that the predominant defects in wüstite in the above region were doubly ionized cation vacancies. The analysis also ruled out the existence of complexes of the type postulated by Roth, except that below 1000°C there is some evidence of 'association of defects. Of the three oxides of iron (FeO, Fe3O4, Fe2O3) only FeO (wüstite) can exist within a wide range of the ratio O/Fe. This has been shown by several investigations of the phase diagram using for instance chemical analysis of quenched samples'-4 or thermogravimetric measurements. 5,8 Darken and Gurry's1 data for example in the temper- ature range 1100o to 1400°C show that the lowest O/Fe ratio obtainable for FeOl +. is about 1.045 and that the existence range extends to O/Fe = 1.20 at 1400oC. On the basis of detailed analysis of thermogravimetric measurements made by Vallet and Raccah6 the existence of three varieties of wüstite at elevated temperatures was suggested by these authors and by Kleman. It is well-established that wüstite has a NaCl structure with vacant cation sites.3, 8 From a neutron-diffraction study of wüstite samples quenched to room temperature Roth9 concluded that defects in wüstite are mostly complexes composed of two cation vacancies and one interstitial cation in a tetrahedral site. The atomic arrangement in the vicinity of such a defect is similar to that in magnetite, where each occupied tetrahedral site is surrounded by four vacant octahedral positions disposed at the corners of a tetrahedron, so arranged that each vacancy is shared by two tetrahedral cations. Thus there is an average of two vacancies per interstitial. Recent X-ray diffraction measurements made by Smuts10 on quenched wüstite samples confirmed the results of Roth's neutron-diffraction experiments. Roth's model of defects in FeO can be regarded as a solid solution of Fe3O4 in FeO; salmon1' used this defect model to calculate the activity of Fe3O1 in FeO at high temperature and claimed good agreement with the results obtained experimentally by Darken and Gurry.' Each missing cation in wüstite is accompanied by two trivalent cations, thus preserving charge neutrality. The "holes" which differentiate between the Fe 2+ and Fe3' states of the ions in octahedral positions can overcome the attractive field of the cation vacancies, and are then free to move through the crystal as charge carriers. A similar picture holds for COO, NiO, andMnO.l2, 13 Localization of the charge carriers in transition

Jan 1, 1968

By Edward Walsh

In the early history of the production of metallic iron from the native oxides or ores, success attended the labors of the workman according to the care he devoted to his work, and according to the degree of skill he possessed in furnishing the required amounts of fuel and ores to be acted upon by the blast propelled by the bellows, trompe, or wooden tub, and delivered into the hearths of the Persian, bloomery, or Catalan forges. The same skill may also have been of avail in the use of the lower forms of the ".Stück," "Blue,"or" Wolf"

Jan 1, 1887

By T. W. Lippert

CUBA fancies herself the "pearl of the Antilles" and, by many, Jamaica is called "blessed." But far to the southward lies what is seemingly the Caribbean's most glittering jewel, the sparsely-settled, Spanish-speaking United States of Venezuela, indeed blessed by nature to a lavish degree. Not a large country, Venezuela is leaping from the donkey to the airplane under the impact of its natural wonders. Angel Falls, dwarfing Niagara and seldom seen by man, is hidden in the cold, primitive and unexplored Guiana highlands along the southeast border. A few hundred miles northwest are the low and torrid coastal plains from which gush unlimited black-gold streams of oil. About midway are the Llanos-low-lying, savanna-type grasslands, beneath which large deposits of bauxite are as yet barely touched by the explorer's diamond drill. And jutting starkly upward 2000 ft from a surrounding expanse of savanna is a small mountain (see front cover), 11 miles long and 1 mile wide. It is, or was, La Parida.

Jan 2, 1950

By Morris Cohen

IT has been known for several years that in certain age-hardenable alloys precipitation of finely divided particles occurs simultaneously with the changes in physical properties; while, in other alloys, these changes take place prior to, or without any, precipitation. . The silver-copper alloys are generally considered to be the classical example of the first group, and the aluminum-copper alloys (duralumin) are typical of the second group. The two types of aging are explained by the precipitation theory and the knot theory respectively. ? It is well recognized now that these theories do not conflict with each other; the one used for a given aging system depends upon which way the alloy in question happens to age-harden. However, previous work on the aluminum-copper alloys1,2 has shown that if the aging temperature is raised sufficiently the hardening will be accompanied by actual precipitation. In fact, it is quite probable that all of the so-called knot-hardening alloys will harden by precipitation at elevated temperatures. Therefore, a combination of the knot and precip-itation theories is necessary to give a complete picture of the age-harden-ing of these alloys, and indicates that knot formation and precipitation are not independent processes. To test the generality of this concept, it is necessary to show that the alloys that commonly harden by precipitation will harden prior to precip¬itation if the aging temperature is sufficiently lowered. For this reason, it would be well to carefully re-examine the aging characteristics of the silver-copper alloys at aging temperatures somewhat below those used by previous investigators. If hardening can be detected prior to precipi¬tation in these alloys, it will lend great weight to the idea that knot forma-

Jan 1, 1936

By Herbert H. Kellogg, Hugo Vasquez- Rosas

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

Jan 1, 1947

By Herbert H. Kellogg, Hugo Vasquez- Rosas

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

Jan 1, 1947

By G. H. Shefelbine

DISCOVERED during the time of the Spaniards, the Namiquipa silver-lead-zinc mines in Chihuahua, Mexico, remained idle until 1916, when mining claims were first denounced. About 1922 a Japanese company, the Santo Domingo Mining Co., was formed to mine the oxide silver ore. The company built a 75-tpd cyanide plant and mined in the area for a number of years. Because of an error in surveying in one of the company's mines situated in another district, mining was carried over into a claim owned by General Marcel Caraveo, at that time governor of Chihuahua. Santo Domingo Mining Co. lost the resulting lawsuit and consequently had no capital to continue operating at Namiquipa. Later, Ray Brown and Eugenio Caballero formed a company to operate the mine, shipping crude ore to the American Smelting and Refining Co. smelter at Avalos, Chihuahua. The cyanide plant was changed to flotation with a capacity of 75 tons per 24 hr. In 1936 the property was again closed owing to labor trouble, a drop in the price of silver, and increased water in the mine.

Jan 10, 1957

By R. Thiessen

The question whether the kind, rank and grade of coal is in any way determined by the kind or type of plant from which it originated has been a problem since coal was first studied. Some investigators claim that the kind of plants has contributed none of the attributes that characterize the differences found in the various coals; others claim that all differences are caused by the contributing plant; and others hold that only a few characteristics are inherited from the kind of plant from which the coal originated. Most coalologists, however, give this matter no thought. It can easily be shown that the kind of plant which contributed to a coal had a marked influence on its kind and type. A number of factors enter into this problem, and all unrelated ones must be carefully eliminated, including metamorphism caused by the pressure of the cover, earth movements, mountain building and higher temperature. Only the fundamental substance—the plants out of which coal was formed—• and the causative conditions that gave rise to a peat swamp and the conditions imposed upon the plant and the plant substances during the formation of the peat swamp can be considered. Everything else being equal, the question then is, how far do different classes and types of coal owe their differences to different kinds or types of plants? Geologic Age of Coal Coal has been laid down in almost every geological period since the Devonian era. Even as early as the middle Devonian some coal was formed; although of no value it has great scientific significance. The most valuable coal was deposited during the Carboniferous. The coals of England were formed during the Mississippian, and most of the valuable coals of America, Europe and China during the Mississippian and chiefly the Pennsylvanian. From the Permian come the coals of France, Saxony, Thuringia and Schwarzwald in Germany and of Bohemia and of the Ural districts of Russia. From the Mesozoic come the coals

Jan 1, 1930

By Paul Billingsley

The Asientos-Tepezala district is in the north of the State of Aguasca-lientes, about 30 miles north of the city of Aguascalientes, the capital. The district is reached by a standard-gage railway on the west side through the junction, Rincon de Romos, which is on the main line of the National Railways of Mexico from El Paso to Aguscalientes. The terminal is Tepezala. On the east side a narrow gage connects Asientos with the junction, San Gil, on the main line, Asientos to San Luis Potosi. Tepezala on the west side of the Asientos hills is about 2 miles from Asientos on the east side. The area between the two mining centers is separated by a low subdued divide which forms the central part of the hills. The district is in a group of isolated hills surrounded by characteristic bolsón plains. The hills rise above the surrounding plains about 6500 to 10,000 ft.; the highest peak is Alta Mira. The two mining districts lie somewhat upon the flanks of the hills at about the same elevation, 7200 ft. The district is an old one and has been known since early in the 17th Century when the mines were worked by the Franciscan Monks. Their mining operations, which were limited to the oxidized ore above the water level, consisted chiefly in extracting silver from the Santa Francisca vein. To judge from the old workings and the remains of surface plant, the operations were on a large scale. By modern mining operations since about 1900, the various mines of the district have been one of the principal sourees of ore for the smelter located at Aguascalientes. Topography The topographic features of the Asientos hills are largely controlled by the character of the underlying rocks. During the Tertiary period, the entire group of hills was probably covered by extrusive volcanic material in the form of cones and lava flows. The central part of these have since been carried away by erosion, so that remnants have been left along the borders of the hills. These remnants form rather conspicuous peaks,

Jan 1, 1927

By Alan F. Stewart, Douglas R. Piteau, Dennis C. Martin

Three examples of open pits where toppling failure controls the stability and design of the slopes are described. Two examples involve the design of overall slopes in base metal mines. The third example concerns the analysis and design of remedial measures to prevent toppling failure from occurring in a critical slope in a coal mine. The analytical techniques for assessing toppling failure on a rational basis are discussed for the three examples. This includes an assessment of the important parameters which govern the stability for the toppling failure mode. The geological setting and input data for each example are described, as are the important external or limiting factors pertinent to the sites in question. A statistical cumulative technique was used to assess one of the most important input parameters in the two examples involving overall slope design. Both deep-seated toppling failures, involving the entire slope, and shallow bench failures are considered. Results of the stability analyses and their related engineering significance with regard to slope stability and design are discussed. A sensitivity analysis of various parameters is effectively utilized. Design charts are developed and evaluated accordingly. In the example where toppling failure was unavoidable, the rationale for design of stabilization techniques to prevent toppling is discussed.

Jan 1, 1983

ALABAMA Aldrich -Thomas, D A Altoona -Cain, J Anniston -Cowie, L K Walmsley, W N White, H E Ashland -Sturdevant, J C Bankhead -Connaway, M B Bessemer-Ball, E M McKenzie, W C, Jr Mitchell, F R Morgan, C Thompson, N E Birmingham -Abbott, C E Adams, J H

Jan 1, 1923

Jan 1, 1879

Jan 1, 1920

By Karl L. Fetters

In the process of making steel in the open-hearth furnace the refining of the metal during the working period of the heat is largely accomplished through the agency of the slag. From the birth of the process until the present day steelmakers have recognized the importance of the slag in determining the composition of the metal and the quality of the product. The general relationships between slag composition and metal analysis have long been known, at least in a qualitative or approximate fashion. For examples, the iron oxide content of the slag is higher on lower carbon heats; the more basic slags are higher in iron oxide for a given carbon content; certain amounts of iron oxide and lime arc required for phosphorus removal and a high lime-silica ratio is needed if the sulphur content of the metal is to be diminished. In recent years a number of quantitative relationships involving these and other variables have been developed through plant and laboratory studies by numerous investigators in this country and abroad. The direct comparison of laboratory and open-hearth data involves the question of the degree to which each approaches the conditions of chemical equilibrium, a question which, from the open-hearth standpoint, we are scarcely yet in position to answer. And, although a considerable body of dependable equilibrium data has been obtained in the laboratory, this work has not yet been extended to cover the ranges of slag composition encountered in basic open-hearth practice. In the present study we shall not attempt to draw comparisons between data from the two sources; nor do we attempt to draw conclusions as to the approach to chemical equilibrium in the open-hearth furnace. Many of the operating variables that are likely to be erratic or unrecorded during the earlier stages of the heat become more consistent and arc more readily subject to observation and control during later stages. For example, undigested lime or ore gradually goes into solution, the rate of carbon drop levels off, and the temperature of the metal is brought under control. For these and other reasons a greater degree of self-consistency is likely to be found among data obtained during the

Jan 1, 1940

By J. B. Austin

In considering so complex a process as the smelting of iron in the blast furnace, there is obviously no single method of calculating efficiency that gives a complete appraisal of the performance of the furnace in all its several functions; such a comprehensive view as is required to evaluate producing ability and manufacturing costs for a given furnace is obtained only by considering a group of efficiencies, each of which measures the performance of the furnace from a specific point of view. For instance, there is the rate of consumption of coke per ton of iron produced, which is probably the most frequently considered, and is certainly one of the most important of the group; there is the efficiency of recovery of iron charged; and there is the efficiency of utilization of energy, both chemical and thermal, in some respects related to the former two yet in other ways independent of either. In each of these cases, the calculation can be made on the basis of the actual input of material or energy, or it may be based upon a comparison with the minimum amount of material or energy that would be required by a "perfect" furnace; that is, an imaginary ideal furnace analogous to the perfect steam engine used in thermodynamic calculations, when this furnace is operating under optimum conditions. Moreover, the furnace itself can be considered either as an apparatus for smelting iron or, taking a somewhat less common point of view, as a gas producer yielding iron and slag as by-products. Some of these efficiencies are more useful than others, yet all are instructive; for a knowledge of them not only leads to good engineering practice from the standpoint of control but also discloses limits to possible improvement in performance and indicates the lines along which improvement is most likely to be profitable. Estimates of some of these efficiencies have appeared from time to time in the literature, but many of them are open to objection because they are based on data of uncertain accuracy or because they have been caleulated without due regard to the thermodynamic principles involved. Moreover, so far as the author is aware. no general survey of the blast furnace comparing its performance in all the aspects mentioned has been made.

Jan 1, 1938