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By David E. Hyatt, Christopher H. Cox, Franklin T. Davis

INTRODUCTION The composition of water used in the flotation process has always been of primary interest to the flotation metallurgist. It is by alteration of the chemistry of the water introduced to the process that flotation separation is effected. In only a few cases has it been necessary to treat available water prior to use in the process. In the past, flotation tailings were treated for the removal of solids via the tailings dam and water decanted from the dam was either recirculated to the process or discharged to the surface water system. The choice of recirculation or discharge was based upon water availability, effect of recycle water on the process, and economic considerations. The Federal Water Pollution Control Act Amendments of 1972 have charged the United States Environmental Protection Agency with establishing effluent limitations from point sources of discharge into the navigable water of the United States. A detailed study, sponsored by EPA, of the water of ore processing plants took place in 1974 and 1975 and guidelines for these plants will presumably have been published by the time this paper has been presented(1). The action of many of the individual states preceded the EPA in this attempt to regulate the quality of the water discharged from industrial point sources. Even with recycle of tailings water, some water is discharged from tailings dams into the substrata and at least one state is currently preparing guidelines for the quality of water discharged into the substrata.

Jan 1, 1976

By Thomas L. Garwood, F. C. Menk

I T is generally accepted that no method of coal cleaning except froth flotation is effective in cleaning dust. In the majority of coals mined in the United States the dust sizes contain a high percentage of impurities, hence the removal of the dust from the coarse sizes lowers the impurity content of these sizes. Dedusted coal is desired as a means of providing a better feed to cleaning plants because of increased efficiency in both dry and wet plants. In dry-cleaning plants, a dedusted feed makes for a pervious and uni¬form bed. With a dusty feed the fines tend to segregate in the feed stream and pass en masse over the air separators, causing a lack of uniform aeration and fluidity of the bed necessary to efficient cleaning. In wet-cleaning plants deducting of the feed often decreases the sludge problem to the point of eliminating the necessity of wasting wash water. It may be advantageous to eliminate sludge-settling equipment in favor of dedusting equipment, to provide the advantages of a dedusted feed to the wet-washing process. Dedusting advantages may include: (1) the removal of fusain, especially advantageous in plants washing coal intended for metallurgical coke; (2) prevention of the gradual build-up of solids in the wash water, with a consequent variation in the washing ability of the system; (3) prevention of the loss of dust to the sludge ponds, providing instead a fuel for local consumption or special markets.

Jan 1, 1943

By Dorsey A. Lyon, Robert M. Keeney

Page I. Introduction..........234 I1. Chemistry oF Copper Smelting...235 1. Native Copper Ores.......235 2. Oxide and Carbonate Ores....235 3. Sulphide Ores.......236 (a) Elimination of sulphur ...236 III. Reverberatory Copper Smelting...237 IV. Substitution of the Electric Furnace for the Reverberatory Furnace..................... 238 V. Smelting of Fine Michigan Native-copper Concentrates in the Electric Furnace.................. 239 1. Conclusions.................240 VI. Proposed Process for Electric melting of Fine Native-copper Concentrates.................. 241 VII. OrdINary Copper Blast Furnace 'Smelting......... 245 1. Prerequisites.................. 245 2. Losses .................... 247 VIII. Experimental Data on the Electric Smelting of Raw Sulphide. Oxidized and Carbonate Ores............. 248 1. Vattier's experiment................ 248 2. Wolkoff's experiments................ 249 3. Experiments of Stephan.............. 250 (a) Conclusions of Stephan ............ 251 IX. Smelting of Sulphide Ores in the Electric Furnace...... 251 1. Ores Treated.................. 252 2. Conclusions................... 253 X. ELectric Furnace vs. the Reverberatory Furnace and Blast Furnace as a Melting Agent.............. 253 XI. Smelting of Sulphide Ores without Roasting or Partial Pyritic Smelting............254 XII. The Electric Blast Furnace vs. the Copper Blast Furnace for Partial Pyritic Smelting.......259 1. Metallurgical conditions......259 2. Mechanical considerations......259 3. Comparison of costs.......260 (a) General considerations .....260 (b) Cost of plant........260 (c) Amount of electrical energy...260 (d) Cost of smelting.......261 (e) Cost of electrodes........262 XIII. The Use of the Electric Furnace in the Smelting of PyRITIc ORES : 262 XIV. Summary...................... 264

Jan 1, 1914

By A. W. Gray

Page CRUSHING STRENGTH...................... 659 The Black Dynamometer....................659 A Standardized Procedure for Crushing Strength Tests...... 660 Influence of Height of Test-piece upon Apparent Strength ..... 662 Influence of Packing Pressure and of Packing Time........ 662 Application of the Logarithmic Law...............665 Influence of Amalgamation Variables.............. 665 Influence of Temperature................... 669 The Transition Region Near 70" C............... 671 Influence of Packing Pressure at Various Temperatures ...... 673 Influence of Age upon Alloy and Amalgam........... 676 DIMENSIONAL CHANGES DURING THE HARDENING OF AN AMALGAM .......................... 678 The Black Amalgam Micrometer............... 678 Thermostated Dilatometer Designed by the Author........ 681 Graphical Representation of Reaction Expansions......... 683 The Typical Reaction Expansion Curve ............. 684 Influence of Packing Pressure................. 686 Influence of Trituration Time................. 687 Influence of Temperature................... 688 Influence of Mercury-alloy Ratio................ 689 Influence of Packing Time................... 689 Influence of Annealing the Alloy................ 691 Influence of Size of Alloy Particles...............691 Extension of the Typical Expansion Curve........... 693 Influence of Thermal Softening and of Reamalgamating a Hardened Amalgam.......................... 634 Curves Obtained with a Variety of Dental Alloys ........ 694 Copper Amalgam ...................... 694 PRACTICAL APPLICATIONS OF THE RESULTS.......... 695 Phenomena which reveal chemical and physical processes that probably go on in many alloys at temperatures not far removed from their melting ranges are observable in dental amalgams. These amalgams should. therefore. be of even more interest to the metallographer, the metallurgistl the chemist. and the physicist than to the dentist who uses them for saving decaying teeth. For this reason I am here de-

Jan 1, 1919

By E. W. Johnson, M. L. Hill

Equilibrium concentrations of hydrogen in iron were measured at H2 pressures up to 136 atm and temperatures down to 145°C. Residual hydrogen was prominent near 600°C in air-melted but not in vacuum-melted iron. The diffusible hydrogen solubility is abnormally high below 390°C, confirming the hypothesis of hydrogen trapping.' It appears that the traps for hydrogen in iron form suddenly on cooling. The estimated H2 pressure in equilibrium with 5 ppm hydrogen in steel at room temperature is less than 1000 atm. It was shown previously1 that the diffusivity of hydrogen in a-Fe below 200°C is anomalously low, a behavior attributed to the presence in the metal structure of hydrogen "traps." The energy of the trapped hydrogen was computed as 4.8 kcal Per g-atom below that of the interstitially dissolved hydrogen. The strongest confirmation of the trap hypothesis should be obtainable from measurements of the hydrogen solubility at low temperatures. such measurements have been performed and are reported in this paper. The "residual hydrogen" effect1'' must be carefully controlled if valid measurements of the solubility are to be obtained, and such an effort was made in the present work. Previous data for the solubility of hydrogen in iron have been summarized by Geller and Sun.3 Their equation for the most probable solubility at 1 atm in a-Fe above 400°C is

Jan 1, 1962

By H. A. Coy

THE Mascot mines of the American Zinc. Co. of Tennessee are situated at Mascot, Tenn., 14 miles northeast of Knoxville, on the Southern Railway. The district is centrally located in the Great Valley, or Appalachian Valley Province. Prior to 1900, a small output of zinc was obtained from oxidized ore mined in open pits. In 1900, a shaft was sunk to sulfide ore, and in 1903, a second shaft was put down, neither being as deep as 200 ft. The American Zinc Co. of Tennessee began drilling in 1911, and outlined an ore body to which its No. 1 shaft was sunk, to a depth of 365 ft. Since that time, the American Zinc Co. of Tennessee has been the only operator in. the district. The Federal mining laws have never been in operation in Tennessee and mining lands are as irregular in boundary and area as farm lands. Ownerships are generally held in fee. In most cases the surface and mineral rights, are transferred together. Electric power is supplied at 66,000 volts by the Tennessee Power do, from a hydro-electric plant at Parksville, Polk County, Tenn., 100 miles from Mascot. No other power is used, but an emergency steam plant is held ready in case of interruption of service. Labor is all native and non-union. Negroes are employed for most of the shoveling, and for a few miscellaneous jobs, but for almost, no other work.

Jan 9, 1924

By James Terry Duce

In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table 1 may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable from data available to the author, please insert y; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of an 0 is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when subtracted, should give the approximate thickness of the productive zone. For fields where this is not true

Jan 1, 1940

By R. I. Jaffee, H. R. Ogden, D. J. Maykuth

Phase diagrams for the Ti-W and Ti-Ta systems were determined. The Ti-W system is characterized by a wide, two-phase region of ß plus tungsten which is derived from a peritectic reaction between the liquid and tungsten solid solutions. The ß field terminates in a eutectoid reaction between a titanium and tungsten terminal solid solution. Tantalum and ß titanium form a complete series of solid solutions. Other features of this system are the extensive a-ß field at low temperatures and an appreciable solubility of tantalum in a titanium. BOTH tungsten and tantalum were first thought to form ß-isomorphous systems with titanium as a result of early work' using powder-metallurgical techniques. Later work2 on arc-melted Ti-Ta alloys, made using a commercial titanium base, showed that, in the range of 0 to 10 pct, tantalum was soluble in ß titanium and that the a solubility extended to between 2 and 5 pct Ta at 790 °C. The present investigation covered the entire alloy range in both systems and was chiefly concerned with high-purity alloys at the titanium-rich end. The constitution of titanium-rich alloys made with a commercial titanium base was reported by Holla-day, Kura, and Jackson.3, 4 As will be shown in detail later, the early prediction of a isomorphism was true for the case of the Ti-Ta system, but not for the Ti-W system. The results of this investigation will be presented first. The experimental methods used are described in the Appendix. Ti-W System The entire Ti-W phase diagram is shown in Fig. 1. Details of the titanium-rich side are shown in Fig. 2. The chief features of the system are a ß eutectoid and a high-temperature peritectic between liquid and tungsten solid solution. Melting Range: Examination of cast structures of low and medium-tungsten-content ingots showed cored ß phase as the primary constituent. Fig. 3a illustrates a typical cast structure for alloys in the range of 20 to 30 pct W. From 30 to 72 pct W, coring was very severe. Alloys containing 72 through 88 pct W, however, showed definite evidence of a peritectic reaction between the liquid and a terminal solid solution of titanium in tungsten. Fig. 3b shows the cast structure for an 80 pct W alloy. A 95 pct W alloy, shown in Fig. 4, consisted primarily of primary tungsten solid solution plus a small quantity of ß probably rejected during cooling. Incipient-melting experiments located the peritectic temperature between 1850" and 1900°C and indicated that the reacting phases are liquid containing about 25 pct W and tungsten terminal solid solution containing about 8 pct Ti. Figs. 5 and 6

Jan 1, 1954

I do not think too much emphasis can be placed upon creation of favorable climate for development of foreign mineral resources to feed the hungry maw of our industrialized nation. We have become dependent, not only upon the ten raw products indicated in Mr. Bancroft's article, but upon 71 mineral substances listed by DMPA as in short supply. Forty-four of these are metals, 9 are chemical minerals and 18 are nonmetallic minerals. Of this list only 8 are produced in any large quantity in the United States, and all are vital in peace-time industry. Even more, they are absolutely essential for defense. This represents our present needs. But if our consumption and requirements are projected over the next 25 years as is done by the President's Materials Policy Commission-The Paley Report-our future outlook becomes appalling. The divergence of consumption over production, even allowing for substitution and conservation, will widen in the future. This means our dependence upon foreign raw materials, mainly minerals, will grow. What are the chief foreign sources of minerals for our future needs? They are chiefly Latin America and the dominions and colonies of the Western European nations. The British Commonwealth countries contain in abundance those minerals which the U. S. lacks. Of 32 of the most critical minerals the Commonwealth is deficient in 7 and lacks only 1; whereas the U. S. is deficient in 18. Strikingly, our deficient minerals are abundant in the Commonwealth and several of their deficiencies are in excess in the U. S. Resources of the two nations complement each other. If Europe should be overrun by an unfriendly power that could control the destinies and resources of the European dominions and colonies, our industrial life would be placed in severe jeopardy. Therefore, I heartily endorse Mr. Bancroft's statements regarding the Point IV program, provided the program is wisely administered and implemented. It is from the underdeveloped countries, as pointed out by Mr. Bancroft, that most of our future mineral supplies will have to come. Many of the underdeveloped source countries are African colonies and dominions of Western European nations. Our present aid to Europe, therefore, is not, as many infer, a purely one-sided affair; it safeguards our future industrial development and security. Development aid directly to the underdeveloped countries through a well administered Point IV program, can do much, I believe, to safeguard our prosperity. I regard it as a wise investment for future U. S. mineral needs. Dr. Alan M. Bateman Department of Geological Sciences Yale University Mr. Howland Bancroft's article, The Broadening Road to Foreign Investment, appeared on page 666 of the July MINING ENGINEERING.

Jan 1, 1952

By James Terry Duce

In order to facilitate interpretation of the data in this chapter, we print the following excerpts from the Circular to Authors. The field is the unit in this tabulation. In cases of fields extending across State boundaries, such as Rodessa, it is suggested that each State author treat the section of the field in his State as a unit, and by a footnote indicate that the field extends into an adjacent State. Each space in Table 1 may represent one of four possibilities; either it is not applicable to the particular field, or the proper entry is not determinable, or the proper entry may be determinable but is not determinable from data available to the author, or the proper entry is determinable. When spaces are not applicable, leave blank; in spaces where the proper entries are determinable from data available to the author, please insert y; in spaces where the proper entries are determinable by the author, make such entries. y implies a hope that in some future year a definite figure will be available. The entry of an 0 is a positive declaration, and an important declaration where it is in order. Inability to determine precisely the correct entry for a particular space should not lead the author to insert merely y. Contributions of great value may be made by the author in many cases where entries are not subject to precise determination. In such cases the author should use his good judgment and make the best entry possible under the circumstances. For many spaces the correct entries represent the opinion of the author (for example, "Area Proved") and in such cases the entry need not be hedged to such extent as when the quantities are definite yet can be ascertained only approximately by the author. In cases under definite headings but where figures are only approximate, the author may use x. It is thought that the nearest whole numbers are sufficiently accurate for our purposes except as to percentage of sulphur in oil. If an author desires to report any other figures to tenths, he may do so. The quantity of gas produced should include, where possible, gas sold or otherwise marketed, and gas blown into the air, burned as flares or otherwise wasted. Segregation of these figures would be interesting if the authors can make such segregation. In any event, the figures should represent as nearly as possible the total quantity of gas removed from the reservoir. Under the columns on "Depth," the average depth to the top of the productive zones and to the bottom of the productive wells, when subtracted, should give the approximate thickness of the productive zone. For fields where this is not true

Jan 1, 1940

By R. R. Knuckey

HAVING been associated with the operation of the de Vooys process for coal, which has treated 13,000,000 tons per annum, and recognizing the process as of value in ore sorting, Huntington, Heberlein and Co. Ltd. (Great Britain) in 1936 made an examination of all other existing methods. In none of the pioneer applications had recognition been given to the necessity for maintaining certain conditions that are essential for sorting certain ores if a truly efficient separation by gravity alone is to be assured. Consequently, in 1936-1937 Huntington, Heberlein and Co. Ltd., with Pearson, employing certain ideas connected with the de Vooys application, commenced the development of a separator that would allow conformance with optimum conditions in the zone where separation is effected. Later, Holt and Wade added to the value of the original application by Wuensch, Rakowsky and others, whose conceptions are being successfully operated today. Meantime, Trostler had enhanced the value of the original H-H. process by improvements that are now embodied in operating plants, and today the process incorporates an improved apparatus and a stable medium that produce the optimum conditions for separation. These conditions are: 1. Elimination of disturbing currents in the separating zone; 2. Reduction to a minimum of medium-density differences throughout. the separating zone; 3. Stable medium of minimum viscosity to permit the unretarded fall of mineralized particles; 4. Removal of products of separation with minimum disturbance to the separating zone. DESIGN OF SEPARATOR The H-H. sink-and-float separator consists of a pyramidal tank in which the separation actually takes place, connected at the bottom with an inclined bucket elevator. The tank and the elevator are filled with medium to within a few inches of the top of the tank. Medium is fed into the separator at a variety of points, according to the type of ore being treated, and it is withdrawn from the separator at two points: (1) together with the float product, by means of a variable-speed paddle, at the surface of the medium, and (2) by flowing over an adjustable weir cut in the side of the elevator casing. The prepared ore is fed onto the surface of the medium. The intermediate paddles, which revolve at a slow speed of 2 to 5 r.p.m., move the floating ore across the bath from feed end to float-discharge end. The ore, which is heavier than the medium, sinks below the sweep of the paddles and reaches the boot of the bucket elevator, which discharges it without disturbance of the separating zone. These arrangements for withdrawing medium from the separator allow the use of minimum flows, which connote minimum

Jan 1, 1943

By R. R. Knuckey

Having been associated with the operation of the de Vooys process for coal, which has treated 13,000,000 tons per annum, and recognizing the process as of value in ore sorting, Huntington, Heberlein and Co. Ltd. (Great Britain) in 1936 made an examination of all other existing methods. In none of the pioneer applications had recognition been given to the necessity for maintaining certain conditions that are essential for sorting certain ores if a truly efficient separation by gravity alone is to be assured. Consequently, in 1936-1937 Huntington, Heberlein and Co. Ltd., with Pearson, employing certain ideas connected with the de Vooys application, commenced the development of a separator that would allow conformance with optimum conditions in the zone where separation is effected. Later, Holt and Wade added to the value of the original application by Wuensch, Rakowsky and others, whose conceptions are being successfully operated today. Meantime, Trostler had enhanced the value of the original H-H. process by improvements that are now embodied in operating plants, and today the process incorporates an improved apparatus and a stable medium that produce the optimum conditions for separation. These conditions are: 1. Elimination of disturbing currents in the separating zone; 2. Reduction to a minimum of medium-density differences throughout the separating zone; 3. Stable medium of minimum viscosity to permit the unretarded fall of mineralized particles; 4. Removal of products of separation with minimum disturbance to the separating zone. Design of Separator The H-H. sink-and-float separator consists of a pyramidal tank in which the separation actually takes place, connected at the bottom with an inclined bucket elevator. The tank and the elevator are filled with medium to within a few inches of the top of the tank. Medium is fed into the separator at a variety of points, according to the type of ore being treated, and it is withdrawn from the separator at two points: (1) together with the float product, by means of a variable-speed addle, at the surface of the medium, and (2) by flowing over an adjustable weir cut in the side of the elevator casing. The prepared ore is fed onto the surface of the medium. The intermediate paddles, which revolve at a slow speed of 2 to 5 r.p.m., move the floating ore across the bath from feed end to float-discharge end. The ore, which is heavier than the medium, sinks below the sweep of the addles and reaches the boot of the bucket elevator, which discharges it without disturbance of the separating zone. These arrangements for withdrawing medium from the separator allow the use of minimum flows, which connote minimum

Jan 1, 1947

By R. R. Knuckey

Having been associated with the operation of the de Vooys process for coal, which has treated 13,000,000 tons per annum, and recognizing the process as of value in ore sorting, Huntington, Heberlein and Co. Ltd. (Great Britain) in 1936 made an examination of all other existing methods. In none of the pioneer applications had recognition been given to the necessity for maintaining certain conditions that are essential for sorting certain ores if a truly efficient separation by gravity alone is to be assured. Consequently, in 1936-1937 Huntington, Heberlein and Co. Ltd., with Pearson, employing certain ideas connected with the de Vooys application, commenced the development of a separator that would allow conformance with optimum conditions in the zone where separation is effected. Later, Holt and Wade added to the value of the original application by Wuensch, Rakowsky and others, whose conceptions are being successfully operated today. Meantime, Trostler had enhanced the value of the original H-H. process by improvements that are now embodied in operating plants, and today the process incorporates an improved apparatus and a stable medium that produce the optimum conditions for separation. These conditions are: 1. Elimination of disturbing currents in the separating zone; 2. Reduction to a minimum of medium-density differences throughout the separating zone; 3. Stable medium of minimum viscosity to permit the unretarded fall of mineralized particles; 4. Removal of products of separation with minimum disturbance to the separating zone. Design of Separator The H-H. sink-and-float separator consists of a pyramidal tank in which the separation actually takes place, connected at the bottom with an inclined bucket elevator. The tank and the elevator are filled with medium to within a few inches of the top of the tank. Medium is fed into the separator at a variety of points, according to the type of ore being treated, and it is withdrawn from the separator at two points: (1) together with the float product, by means of a variable-speed addle, at the surface of the medium, and (2) by flowing over an adjustable weir cut in the side of the elevator casing. The prepared ore is fed onto the surface of the medium. The intermediate paddles, which revolve at a slow speed of 2 to 5 r.p.m., move the floating ore across the bath from feed end to float-discharge end. The ore, which is heavier than the medium, sinks below the sweep of the addles and reaches the boot of the bucket elevator, which discharges it without disturbance of the separating zone. These arrangements for withdrawing medium from the separator allow the use of minimum flows, which connote minimum

Jan 1, 1947

By C. P. Kempter, H. L. Brown

Recently Chang determined heat content values of tantalum monocarbide and tungsten monocarbide from 325" to985°Kand 326" to 912"K, respectively, and, using other published data, made certain solid-state calculations for these two compounds. Chang expressed his Cp values in units of cal per "g-atom alloy" OK. We consider this poor usage since l) tantalum monocarbide and tungsten monocarbide are not alloys, and 2) an atom of an alloy does not exist. However, one may convert his values to units of cal per mole OK by merely doubling them. For TaC he calculated a Nernst-Lindemann parameter of 9.07 x lo-' "g-atom per cal". We have refined the calculation of this parameter and have arrived at a much lower value. Rather than approximating the true coefficient of volume expansion, a,, as three times the true coefficient of linear expansion, a, we calculated u, from the TaCo.99, lattice expansion data of Fries and Wahman.38 At 25°C a, = 14.3 x 10s per OC. The molar volume was calculated to be 13.32 cu cm per mole at 25°C. From the lattice compression data of Champion and Drickamer~' for "TaC,.,," we determined the room-temperature compressibility to be 3.5 x 10-l3 sq cm per dyne by plotting l/Vo (aV/ap) vs applied pressure. (Since the lowest pressure at which Champion and Drickamer reported a relative volume was 20 kbars, one may calculate an approximate compressibility only. Chang calculated a compressibility of 3.175 x 10-l3 sq cm per dyne from the same data.) We also used twice Chang's value of Cp = 4.38 cal per "g-atom alloy" OK for the molar heat capacity at 25°C. From these four values we calculated a Nernst-Lindemann parameter of 5.8 x 10-l4 mole per erg or 2.4 x lo- ' mole per cal, and a Cdil value of 2.3 x 10' ergs per mole OK. In the case of tungsten monocarbide no isothermal compressibility has been reported; however, one may calculate an approximate Nernst-Lindemann parameter by using the adiabatic compressibility reported by Brown, Armstrong, and Kempter." Using the WC lattice expansion data of Mauer and Bolz~l we calculated a, to be 12., x l0-' per OC. The molar volume was calculated to be 12.5 cu cm per mole. We used twice Chang's value of Cp = 4.18 cal per "g-atom alloy" OK for the molar heat capacity at 25°C. From these four values we calculated an approximate Nernst-Lindemann parameter of 2 x lo-' mole per cal, which is much

Jan 1, 1969

By M. W. Dumais, E. P. Abrahamson

In a paper by Abrahamson and Alexander concerning a series of correlations between electronic structure and property changes, it was hypothesized that each solute atom in a dilute solution had a characteristic volume of solvent atoms over which some form of electronic interaction occurred. From this description it is possible to picture the solute atoms as occurring in an ordered array for the most efficient arrangement. A recent review article2 has shown that some form of anomaly exists for a whole series of properties when dilute additions of tungsten are made to iron, of. Fig. 1. Any mechanism to fit one property must also be amenable to mechanisms for the other properties. The possibility of some structural change in this region appears to offer the best hope. The system chosen for investigation was the iron tungsten system. Zone-refined iron with zone-leveled tungsten additions were supplied by Materials Research Corp. as 3/8-in.-diam bars. Transmission electron microscopy was used to study the structure. One-quarter inch specimens of each alloy were cold-rolled to 10-mil sheets, cleaned, punched to electron-microscope specimen-holder size, and annealed in vacuum for 2 hr at 800°C and 2 hr at 700°C followed by a furnace cool. The specimens were attached to a platinum wire and the specimen edge and wire were painted prior to thinning in a solution of 10 pct perchloric acid in glacial acetic acid. It was believed that if ordering were present due to electronic interactions the polishing procedure chosen would provide a simultaneous combination of chemical attack and electropolishing to exhibit the ordered structure. The chemical attack would be expected to penetrate those areas equidistant from the tungsten atoms, while the electropolishing would serve to "plane off" the volumes where the chemical attack had taken place. If one of the ordered tungsten planes were parallel to the specimen face at the edge of the thinned hole, a plate or micalike structure would be expected. A typical result of this polishing is shown in Fig. 2. Here a series of plates can be seen lying one upon the other. In several other specimens the plates parallel to the electron beam have been observed, behaving like slices of bread in a loaf. These edge views coupled with moire patterns indicate that the minimum plate thickness is 37 to 42A. This is equivalent to a concentration of 455 at. ppm of W if a simple cubic superlat-tice exists, or one tungsten atom every twelve iron atoms on the ordered plane. It was further noted that the base iron exhibited no signs of platelike structure. As the concentrations increased above 100 at. ppm W the amount of plate material increased. Among the specimens investigated was that shown

Jan 1, 1967

By S. Beatty

RECENT experimental results' on the superconductive properties of vanadium indicate that the magnetic behavior of the metal is greatly affected by internal strains caused by mechanical work, and particularly by oxygen and nitrogen impurities. These result in an increase in the hardness of the metal such that metallurgists' have used hardness as a measure of the impurities. An increase in the impurities should also be reflected in a change of lattice parameter with increasing impurity content. The lattice parameter of vanadium prepared by the thermal decomposition of the iodide has been determined by two workers. Neuburger3 obtained a value of a, =3.0338 ± 0.0003A for the body-centered cubic lattice by means of the powder method. The work of Katelaar is referred to by van Arkel4 in which a value of a0 = 3.025 is given. Four samples were used for this investigation. Sample A, the vanadium of the highest purity in the group, was obtained by means of the thermal decomposition of vanadium diiodide and deposited on a 3 mil diam tungsten filament in the form of crystals. The second sample, labeled B, was obtained by the calcium reduction of the pentaoxide at a sufficiently high temperature to give a melt. A third sample, C, was obtained in the same manner as B but remelted in a pure argon atmosphere. The last sample, D, was prepared by the calcium reduction method and the fine powdered vanadium was then sintered by means of applied heat and pressure. Samples A, B, and C were thus essentially free of mechanical strain in their preparation. Sample D was annealed in a high vacuum at 800°C. The samples were prepared for X-ray diffraction analysis such that all additional strain by cold work or by contamination with oxygen and nitrogen was kept at a minimum. Powder obtained from filings was deemed unsuitable since this would require annealing to get rid of the cold work. A heat treatment up to 1000°C at 10-6 m pressure might still increase the impurity content by means of adsorbed oxygen from residual gas in the vacuum chamber. The most satisfactory samples were prepared for back-reflection film techniques. Samples were cut to size, etched with hydrobromic acid, and mounted in Bakelite. They were then lightly polished on 3-0 paper and lightly etched. Chemical and Hardness Analysis of Samples Spectrographic analyses were made of the four samples and indicated similar metallic impurities for the group. The major metallic impurity in each sample was iron, which was less than 0.01 pct. The sum of the other metallic impurities was approximately 0.1 pct. The carbon content was assumed low by virtue of the methods of sample preparation. The principal impurity difference between the samples was in the oxygen and nitrogen content.

Jan 1, 1953

By Carter S. Cole

Mr. Chairman, Fellow Members and Guests, our chairman this morning got over into the geneological field, so perhaps I may be pardoned if I revert to some of my ancestral training and give you a text. I always like to talk about some special little text that may illustrate what we want to say. So the text that I will take for this afternoon is a very simple one, "Win the War." That is the guide for all of our actions, or should be. We should question everything we do to see what it does to contribute to winning the war. If we fail to do that, nothing else is going to count. On the wall of the office of one of the branch chiefs in the Copper Division in Washington there is a little slogan which I think we should take very deeply to heart, "The difficult we do right away. The impossible takes a little longer." I think that is a very good guide for us to follow in the work that lies ahead of us in the metallurgical field and in the handling of these secondary metals and the things that result therefrom. My subject is "Conservation and Specifications." Some people would wonder just where that fits in, and how you might define "conservation." One very good definition would be "the utmost use of our resources." If you will pardon my going back to some of my earlier experience for a little simile, those of you who know me know that for ten years after the last war I was in the railroad business. If we are with the engineman in a cab, and we have a green signal ahead of us, that is a clear signal and tells us to proceed at full authorized speed. Now suppose we come to a yellow signal that is caution, slow down to one-half authorized speed and be prepared to stop. Now if you do slow down, the chances are that that obstruction that was ahead of you will move out of the road, and you may get another yellow or caution signal at the next block, and be able to keep going at a slow speed. As of the date of Pearl Harbor our tin supply took on a very yellow tinge, and it threw the caution sign right in our faces. If we had not heeded that sign, and cut down our consumption of tin, we would not have any today; but because we have done so we are in a much better position today than we were a year ago, that is comparing our visible supply with our present rate of consumption as contrasted with the visible supply a year ago and our then rate of consumption.

Jan 1, 1943

Duval Corporation, the owners of the Sierrita, Esperanza, and Mineral Park copper operations in Arizona, first acquired the mineral rights to their Battle Mountain, Lander County, Nevada, property in 1962. Development of the mine commenced in mid - 1965, and the copper operation began at the end of 1968. The ore, a mixture of chalcocite and chalcopyrite, was milled and floated at a rate of 3, 175 mtpd (3,500 stpd). Because of low copper grade and price, the plant was shut down after about ten years of operation. Attention was then turned to an adjacent low-grade precious metal ore body which contained 2.74 g Au and 3.4 g Ag per mt (0.08 oz Au and 0.10 oz Ag) and minor amounts of copper. Test work revealed recovery by Carbon-In- Pulp treatment would amount to approximately 2.8 mt (90,000 oz) each of gold and silver per year. A rapid engineering and construction schedule resulted in the world's largest, as of late 1980, Carbon-In- Pulp plant being put on-stream in January 1979, with a capacity of 2.720 mtpd (3,000 stpd). Fortunately, the original crushing and grinding plant with all its infra structure was available, and the only modification needed was the addition of a gravity circuit to remove coarse free gold ahead of Carbon- In-Pulp treatment. One of the four primary 500 mm (20 in.) cyclone underflows in the primary ball mill circuit is directed to a secondary ball mill where its product is again cycloned. The cyclone underflow is screened at 3,360 microns (6 mesh) with the undersize being treated on two Pan American 1.07 m by 2. 14 m (42 in. by 84 in.) jigs. Hutch product is further concentrated on two Wilfley tables, a magnetic separator, and on a third Wilfley table where approximately 930 g (30 oz) of gold are recovered each day for amalgamation, retorting, and smelting. Returning to the grinding circuit, the final cyclone overflow is sent to the original plant tailings thickener to obtain proper pulp density for Carbon-In-Pulp treatment. Thickener underflow, at about 40% solids, is then conditioned with air and lime in a series of two 8.5 m by 9.75 m (28 ft by 32 ft) 15O cone bottom Pachucas for oxidation of pyrrhotite. The pulp is then split into two streams for cyanidation for 48 hours in two lines of eight Pachucas of the same size. Pulp is transferred from tank to tank by auxiliary air lifts. Cyanided pulp is then sent to a series of six C. I. P. mechanically agitated tanks with one hour retention in each tank. Originally these

Jan 1, 1981

By D. B. Carson, D. L. Katz

Natural gases under pressure form crystalline hydrates with water. Experimental data are reported on four-phase equilibrium for the methane-propane-water, methanc-pentane-water, and methane-hexane-water systems. Temperatures and pressures for equilibrium between gas, water-rich liquid, hydrocarbon-rich liquid, and hydrate were measured, as well as the percentages of methane and propane in the hydrate. The data indicate that natural gas hydrate behaves as a solid solution and that pentanes and heavier hydrocarbons do not enter into the solid phase. Vapor-solid equilibrium constants are presented that permit the approximation of the conditions for hydrate formation, from the composition of a gas. Introduction Natural gas hydrates have been the object of considerable research in recent years, because of the trouble they have caused in the natural-gas and natural-gasoline industries. Natural gas hydrates are white crystalline compounds of water and gas, which, under pressure, exist at temperatures considerably above the freezing point of water. Because of the relatively high temperatures at which the hydrates exist, they become a nuisance in high-pressure gas operations where water is present, since their formation causes partial or complete plugging of valves and pipes. From a practical standpoint, the trouble incident to hydrate formation has been solved by dehydration of the gas before it enters the plant or pipe line, or by other remedial measures. Extensive work on gas hydrates in the latter part of the nineteenth century, by Villardl and others, gave data on methane hydrate and on ethane hydrate. Schroeder summarized these theoretical studies2 Hammerschmidt3 introduced the information on gas hydrates to the gas industry and Dcaton and Frost4-6 gathered a considerable number of data on the behavior of natural gas hydrates. Recent papers7,8 have extended both the data and the theory of these hydrates. At present, data are available on tem-peraturcs and pressures of hydrate forma. tion for pure methane, ethane, propane, n-butane, methane-ethane mixtures, meth-ane-propane mixtures, methane-butane mixtures, and some Is natural gases, all- in the Presence of excess water. However, up to the Present time no method has been available for predicting the temperature at given pressures or the pressure at given at at which natural gases will form hydrates if hydrates with water. 'This Paper Presents data on the methane-propane-water, methane-pentane-water and methane-hex-""e water systems in four phases, one of which is the hydrate. he application of the phase rule to the methane-~ro~ane-water data Proves that hydrates behave as solid solutions. The data of this paper and those in the literature were used to develop vapor-solid. equilibrium constants,8 which permit prediction of conditions of hydrate formation from the analysis of a natural gas.

Jan 1, 1942

By Arthur F. Taggart, Nathaniel Arbiter

The fact that the floatability of minerals with fatty-acid collectors changes as the pH of a pulp varies was utilized in the early days of flotation, when sulphuric acid was used with oleic acid to float sphalerite and galena. from gangues which themselves float with fatty acids in alkaline pulps. Gaudin1 showed that this difference in floatability is a regular function of the extent of the change in pH. The present paper offers an explanation of the phenomenon, and on the basis thereof sets up recommendations for control of soap-flotation operations. Experimental Parallelism between floatability of a mineral in a given environment and its contact angle in that environment is so well established,2 and the contact angle is so readily and rapidly measurable, that contact angles have been used throughout the experimental work to indicate relative floatability. Experiments comprised contact-angle measurements on a number of representative minerals and metals, and a variety of subsidiary tests designed to check and to amplify the contact-angle indications. Contact-angle measurements were made by the method described in detail by del Giudice.3 Sequence of procedure for determination of the points of Fig. I was: I. Polish specimen. Most specimens yielded zero contact angle after polishing; a few showed a slight "cling." Cling is characteristic of specimens that pit on polishing; it is due to a residue of organic contamination, originally on the particle surface, which persists in the pits. The cling did not change total contact angle after conditioning, and is not, therefore, additive in the upper part of the curves of Fig. I. It may have broadened the bases of the curves for the affected minerals slightly. 2. The specimen was next conditioned in soap solution for 5 minutes. 3. The conditioned particle was transferred, under conditions that precluded surface drying, to an aqueous solution of the pH desired and contact angle determined. 4. The particle was thereupon transferred, again without surface drying, to water. The confirmatory tests will be described at the places pertinent in the argument. Discussion of Results Gaudin and Vincent4 have shown that contact angles with heptoic acid as a collector decrease for a given specimen when the concentration of collector present falls below a certain value. A similar reduction in angle occurs with collector-conditioned particles that are visibly slime-coated, and varies roughly with the extent of coating. Since in the last case the reduction in angle is certainly due to reduction in the proportion of total conditioned mineral surface presented to the bubble, the authors believe that the same condition prevails in the first case cited, and that similar reduction in angle and floatability will occur whenever starvation quantities of collector are present, whether by design or by reason of excessive consumption.

Jan 1, 1943