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

The dijfusiuity D was determined at 25° to 780°C- from hyd?-ogen evolution rates. Anomalous evolution from air-melted iron was att~zbztted to residual hydrogen, which is interpreted as a hydrogen compound that decomposes at a strongly temperature-(Ieperzdent rate above 500°C. Above 200°C, D = 0.0014 cm2sec-1 exp (-3200 cal per g atom/RT). Below, 200°C the diffusivity is anomalously low and represented by D = 0.12 cm2sec-l exp (-7820 cal per g atom/RT). It is postulated that at low temperatures the hydrogen in the metal is "trapped" with an energy 4.8 kcaL per g atom below- that of the interstitial hydrogen. 1 HE purpose of the present experimental study was to determine the diffusivity of hydrogen in a-Fe over an extended temperature range. As certain anomalies were encountered, attempts were made to understand the anomalies themselves. This research was in progress both before and after a determination of the diffusivity of hydrogen in nicke1.l The latter system was found to exhibit none of the anomalies of hydrogen in iron, and its description was far simpler. The experiments on nickel also

Jan 1, 1961

By James Terry Duce

Production of oil in Bahrein for the war years was as follows: YEAR BBL PER YEAR Prior to 1939 . . . . . . . . . . . . . . 22,287,055 1939 . . . . . . . . . . . . . . . . . . . . . . 7,588,554 1940 . . . . . . . . . . . . . . . . . . . . . . 7,073,919 1941 . . . . . . . . . . . . . . . . . . . . . . 6,794,157 1942 . . . . . . . . . . . . . . . . . . . . . . 6,240,627 1943 . . . . . . . . . . . . . . . . . . . . . . 6,571,609 1944 . . . . . . . . . . . . . . . . . . . . . . 6,713,795 1945 . . . . . . . . . . . . . . . . . . . . . . 7,308,938 Total to Jan. 1, 1946 . . . . . . . . 70,578,654

Jan 1, 1946

By W. G. Fischer, S. R. Felde

Trona ore at the Westvaco, Wyo., mine of FMC Corp. has been obtained by room-and-pillar methods since the mine began operation. The flat- lying, 10-ft thick trona (Na2CO3.NaHCO3.2H2O) is covered by 1500 ft of weak shale and sandstone, and extraction of pillars on the retreat quite often throws large amounts of weight onto development workings. Weak shales in the roof and floor fail rapidly, and the mine ribs slough to such an extent that mining often becomes very difficult. When this occurs, efficiency goes down, costs go up, and the risk to men and machinery increases greatly. Difficult mining conditions in the early '60s forced a re-evaluation of all presently known mining techniques in bedded deposits. Many room-and-pillar mining plans were compared with the system in use at that time, but none of them offered a better solution to the roof control problem. Longwall techniques were also seriously considered, but machinery was not available that would cut the hard trona seam and still maintain the productivity obtained from room-and-pillar sections. However, since roof control in the longwall methods appeared to be more satisfactory than that found in room-and-pillar techniques it was believed that a new technique using the longwall principle and based on rock mechanics should be tried rather than previously known pillaring methods.

Jan 4, 1966

By George A. Connell

BORAX, a sodium borate and the principal sodium salt of boric acid, has been surrounded with romance and with a certain amount of mystery. Its early history is not entirely known but it has been contended that Marco Polo in his travels in the Orient introduced this material to the West during the Middle Ages. Without doubt its first source was from Central or Eastern Asia and perhaps from Tibet. The well-known fluxing properties of borax probably introduced its earliest use that of a soldering flux in the manufacture of jewelry. This use, as well as the remote location of most borate deposits, added greatly to the romance associated with the thought of borax. COMPOSITION The common element in all borates is boron but this element has never been discovered as such in any deposit, because of its great affinity for oxygen. Incidentally, this makes its manufacture extremely difficult and expensive. Elemental boron undoubtedly has many properties that make it quite valuable but the extreme cost involved in producing it from its oxidized form prevents its general use or manufacture. The common element in all borates is boron but this element has never been discovered as such in any deposit, because of its great affinity for oxygen. Incidentally, this makes its manufacture extremely difficult and expensive. Elemental boron undoubtedly has many properties that make it quite valuable but the extreme cost involved in producing it from its oxidized form prevents its general use or manufacture. The common element in all borates is boron but this element has never been discovered as such in any deposit, because of its great affinity for oxygen. Incidentally, this makes its manufacture extremely difficult and expensive. Elemental boron undoubtedly has many properties that make it quite valuable but the extreme cost involved in producing it from its oxidized form prevents its general use or manufacture of disodium tetraborate (Na2B4O7.10H2O), and, further, can be considered as the acid salt of monosodium metaborate. However, the term "acid salt" might imply that borax gives an acid reaction in solution, which is not true, since solutions of borax are decidedly alkaline, giving a pH of 9.2. Boric acid, also known as boracic acid, has the chemical formula H3BO3; it occurs in nature as the mineral sassolite. Sassolite has been

Jan 1, 1949

By AIME AIME

MOST of the copper mines in Canada are favored by nature in having other metals besides, copper in their ore, which puts them in a most satisfactory competitive position. Noranda ore has an important gold content, Flin Flon gold and zinc, and International Nickel of course has nickel. All of the larger copper companies in Canada operated during 1.933 and the total production of copper exceeded that of the year before. The Britannia Mining and Smelting Co. worked out to succcessful conclusion a three-product flotation process for separating the copper, zinc and iron from its low-grade ore. Although the method and equipment is different from that used at the Flin Flon mine, the object is the same, that

Jan 1, 1934

GENERAL COMMITTEE GERALD F. G. SHERMAN, Chairman. ARTHUR NOTMAN, Secretary. NORMAN CARMICHAEL, JOHN C. GREENWAY, W. L. CLARK, W. G. McBRIDE, B. BRITTON GOTTSBERGER, FOREST RUTHERFORD. General Committee on Transportation WALTER DOUGLAS, Chairman. CLEVELAND E. DODGE, Secretary. ARTHUR S. DWIGHT, JOHN C. GREENWAY, JULIUS KRUTTSCHNITT, JR. Committee at El Paso W. D. GORDON, ROBERT McCART, JR., W. W. ROSE. Committee at Santa Rita JOHN M. SULLY, Chairman.

Jan 12, 1916

By Maurice Ewing, L. Don Leet

Assuming that wave velocities in seismic prospecting increase as a continuous linear function of the depth, the authors have derived formulas for computing, from two time-distance observations, the amount of velocity increase, depth of penetration and a graphical determination of the path of the vibrations, and have discussed the ground, reflected and refracted waves. The application of the formulas is illustrated numerically. Earlier Investigations Observations of the energy propagated from the center of an earthquake disturbance have been used to give information about the velocities and paths of elastic waves in the interior of the earth. One method of accomplishing this depends on the use of the times of transmission. Herglotz(7) § and Bateman(3) obtained a solution of the integral equation involved, which determines the velocity of propagation at any point as a function of the distance from the center of the earth, with no assumption as to the manner in which the velocity of the disturbance varies with depth below the earth's surface. The expressions on which the value of the time and the form of the ray of propagation depend contain an unintegrable definite integral, involving the velocity as an unknown function of the distance from the center of the earth. Wiechert and Zoppritz(15) obtained a manageable form for this function by assuming a law of variation which required a constant curvature form for the path within each of a succession of concentric spherical layers of the earth. C. G. Knott(9) worked out the problem for the first time by an absolutely rigorous method from the data of observation (Zoppritz-Turner tables), without making any assumptions as to the functional relationship connecting the speed of propagation and the distance from the earth's center. His method is a numerical solution of an integral equation, giving each velocity and the corresponding distance from the center of the earth in figures.

Jan 1, 1932

By F. A. Crossley

The titanium-rich end of the Ti-A1 system has been investigated up to 35 at. pct A1 (23 wt pet). One conzpound Ti3Al was found to occur between primary a and TiAl. It is ordered hcp with DO19 structure, it has virtually no solid-solubility range, and it has a closed maximum at about 875°C. OIL either side of the compound are a +Ti3Al two-phase fields. The limiting a1uminum solubility in primary a at the titanium-rich end is indicated to be 7.5 at. pct A1 (4.4 wt pet) at 550°C and about 6.8 at. pct Al fl wt pct) at 500°C. Quenching alloys from above the a + Ti3Al two-phase field produces the following structures with respect to alloy composition: Up to 13 at. pct A1 (7.8 wt pet), a solid solution; from 15 to 18 at. pct A1 (9 to 11 wt pct), shear transformation product or martensite; from 19 to approximately 30 at. pct (11 to 19 wt pet), submicro-scopic coherent Ti3Al in an a malvix. The twin hcp phase fields reported in the literature are the result of nonequilibrium corzdztions. Ti-A1 alloys, once partitioned by dwelling- in the a + ß phase field during either hot working or heat treatment, are extremely difjicult to homogenize at temperatures below 1000°C. Such partitioned alloys exhibit the characteristics or symptoms of two-phase materials, and may be said to suffer the "twin-phase syndrome". THE earliest investigations of the Ti-A1 system by Ogden et al.1 and Bumps et al.2 reported wide solubility of the primary solid solutions. Aluminum was reported soluble in the low-temperature allomorph to the extent of 37 at. pct (25 wt pct), and the first intermediate phase was reportedly TiA1. Somewhat later Kornilov et al.3 reported a similar diagram with phase boundaries displaced towards lower aluminum contents and higher temperatures. Beginning about this time (1956) reports in the literature made it very clear that one or more intermediate phases occurred at lower aluminum contents than TiAl.4-17 These reports included five major investigations of the titanium-rich end of the Ti-A1 diagram.4,12,14,16,17 Three of these diagrams show two two-phase fields below 37 at. pct Al, while two of them show a single two-phase field. The existence of the phase Ti3A1 is firmly established and is included in each of the diagrams, except one—that of Sato and Huang.12 The new phases are reportedly hcp and differ from primary a only slightly when disordered, and when ordered the "a" parameter is approximately one,4,12,15 two, 6-10,13,14 or four14 times that for primary a. Beyond this, however, the diagrams are remarkable for their lack of agreement. Two tacit assumptions are usually made in phase-diagram determinations of metal systems. These are: 1) equilibrium anneals bring the alloy to equilibrium or to indistinguishable closeness to it, and 2) equilibrium conditions established at elevated temperatures are either "frozen" by rapid quenching for evaluation at room temperature, or quench-transformation products are recognized as such. In the current investigation evidence was obtained that over substantial composition ranges neither of these two conditions was met in any of the more recent major investigations. I) MATERIALS, METHODS, AND TECHNIQUES The alloys of this investigation were prepared by nonc on sum able electrode arc melting. Materials used in the preparation of the alloys are summarized in Table I. The investigative tools employed were: optical and electron microscopy, differential thermal analysis (DTA), disatometry, X-ray diffraction, electron diffraction, and resistometry. Alloys for microscopic and X-ray investigations were prepared as 15-g melts. Alloys containing from 7 through 11 at. pct A1 were hot-rolled out of a furnace at 900°C, from 12 through 15 at. pct out of a furnace at 1000°C, and from 16 through 18 at. pct out of a furnace at 1125°C. Alloys containing more than 18 at. pct A1 could not be hot-rolled. The ingots were covered with Markal coating prior to hot rolling to minimize atmospheric contamination. After hot rolling, alloys containing up to 15 at. pct A1 were ground and pickled to remove 7 mils from each surface; alloys containing 16 and 18 at. pct A1 were skinned to a

Jan 1, 1967

By Walter Lang

The year 1931 has shown a marked change over 1930 in New Mexico, with respect to the volume of activities attendant upon the petroleum industry. Although the total production of oil and gas this year exceeds that of preceding years, the results have been attained from established units operating under restriction, but capable of supplying far more than the economic conditions justify. The presidential order of March 12, 1929, that "there will be complete conservation of Government oil in this administration," has merely anticipated a normal consequence of overdevelopment. As a result of the combined economic and legal restrictions imposed, very little new drilling has occurred during the year. Even in proven areas the drilling of offsets has been curtailed to the absolute limit of requirements. Scouting and sample-cutting, which in 1930 were still in a state of feverish activity, are at low ebb, and lease buying has reached a condition of stagnation. A number of the major oil companies have either materially reduced their field and office forces or completely eliminated local office representation. Two tests of particular interest, because correlation shows them to be structurally high although they failed to produce, are the National Securities well drilled six miles west of the town of Hobbs, on sec. 33, T.18 S., R.37 E., Lea County, to a total depth of 4272 ft., which developed a flow of 4,000,000 cu. ft. of gas at 3860 ft., and a show of oil; and the Western Drilling Co. No. 1 State, sec. 16, T.20S., R.32 E., Lea County. The latter test found dead oil at 2575 to 2580 ft., and sulfur water at 2745 ft., increasing to 2780 ft., representing the zone from which production was generally expected. The well was drilled to 4013 feet. The discovery of sulfur at about 950 ft. in the deepening of an old water well (Pearson, NE. 1/4 sec. 8, T.16 S., R.25 E.) drilled in the Little Cottonwood area northwest of Artesia led the Union Sulphur Co. to drill three prospect tests on a block of acreage in the vicinity during the summer and fall. The results of the investigation have not been disclosed. The Kummbaca Oil and Gas Co. drilled the T. J. Kerline No. 1, in sec. 34, T.21 N., R.30 E., Harding County, gaging 3,654,000 cu. ft. of 98 per cent CO² at 940 ft. The Barton structure, 20 miles east of Albu-

Jan 1, 1932

By J. E. Harris

The metallic elements, beryllium, calcium, cerium, lithium, manganese, titanium, vanadium and zirconium are used in metallurgical practice in relatively small percentages for the purpose of improving the physical properties of various alloys. No important uses for any of these elements have thus far been developed either in the pure form or in alloys of which they constitute the major constituent.

Jan 1, 1935

PAST AND PRESENT CHAIRMEN OF DIVISIONS Institute of Metals Iron and Steel Mineral Industry Industrial Minerals Year Division Petroleum Division Division Coal Division Education Division Division 1918 W. M. CORSET 1919 " 1920 W. H. BASSETT 1921 " 1922 W. B. PRICE RALPH ARNOLD 1923 E. DEGOLYER 1924 G. B. ELLIOTT 1925 F. JULIUS FOHS 1926 P. D. MERICA 1927 11 JOHN. M. LOVEJOY 1928 S. SKOWRONSKI A. W. AMBROSE RALPH H. SWEETSER ' 1929 " J. B. UMPLEHY G. B. WATERHOUSE 1930 ZAY JEFFRIES C. V. MILLIKAN W. J. MACKENZIE HOWARD N. EAVENSON 1931 SAM TOUR C. E. BEECHER F. M. BECKET 1932 C. H. MATHEWSON EARL OLIVER F. N. SPELLER THOMAS G. FEAR C. H. FULTON 1933 T. S. FULLER W. E. WRATHER JOHN JOHNSTON ELI T. CONNOR " 1934 J. L. CHRISTIE H. D. WILDE, JR. L. F. REINARTZ " T. T. READ 1935 W. M. PEIRCE HARRY H. POWER A. B. KINZEL JOHN T. RYAN SAMUEL H. DOLBEAR 1936 E. H. DIX, JR. HALLAN N. MARSH C. E. WILLIAMS EUGENE MCAULIFFE WILLIAM B. PLANK OLIVER BOWLES 1937 A. J. PHILLIPS M. ALBERTSON FRANCIS B. FOLEY J. B. MORROW " CHESTER A. FULTON 1938 R. F. MEHL G. B. CORLESS J. T. MACKENZIE PAUL WEIR FRANCIS A.THOMSON J. R. THOENEN 1939 R. H. LEACH W. H. GETS J. HUNTER NEAD C. A. GIBBONS " M. M. LEIGHTON 1940 E. M. Wise T. V. MOORE F. T. SISCO C. E. LA WALL W. R. CHEDSEY W. M. WEIGEL 1941 D. K. CRAMPTON E. A. STEPHENSON C. H. HERTY, JR. JULIAN E. TOBEY " PAUL M. TYLER 1942 CARL E. SWARTZ HARRY P. STOLZ E. C. SMITH NEWELL G. ALFORD A. F. GREAVES-WALKER B. L. MILLER

Jan 1, 1942

PAST AND PRESENT CHAIRMEN OF DIVISIONS Institute of Metals Iron and Steel Mineral Industry Industrial Minerals Year Division Petroleum Division Division Coal Division Education Division Division 1918 W. M. CORSET 1919 " 1920 W. H. BASSETT 1921 " 1922 W. B. PRICE RALPH ARNOLD 1923 E. DEGOLYER 1924 G. B. ELLIOTT 1925 F. JULIUS FOHS 1926 P. D. MERICA 1927 11 JOHN. M. LOVEJOY 1928 S. SKOWRONSKI A. W. AMBROSE RALPH H. SWEETSER ' 1929 " J. B. UMPLEHY G. B. WATERHOUSE 1930 ZAY JEFFRIES C. V. MILLIKAN W. J. MACKENZIE HOWARD N. EAVENSON 1931 SAM TOUR C. E. BEECHER F. M. BECKET 1932 C. H. MATHEWSON EARL OLIVER F. N. SPELLER THOMAS G. FEAR C. H. FULTON 1933 T. S. FULLER W. E. WRATHER JOHN JOHNSTON ELI T. CONNOR " 1934 J. L. CHRISTIE H. D. WILDE, JR. L. F. REINARTZ " T. T. READ 1935 W. M. PEIRCE HARRY H. POWER A. B. KINZEL JOHN T. RYAN SAMUEL H. DOLBEAR 1936 E. H. DIX, JR. HALLAN N. MARSH C. E. WILLIAMS EUGENE MCAULIFFE WILLIAM B. PLANK OLIVER BOWLES 1937 A. J. PHILLIPS M. ALBERTSON FRANCIS B. FOLEY J. B. MORROW " CHESTER A. FULTON 1938 R. F. MEHL G. B. CORLESS J. T. MACKENZIE PAUL WEIR FRANCIS A.THOMSON J. R. THOENEN 1939 R. H. LEACH W. H. GETS J. HUNTER NEAD C. A. GIBBONS " M. M. LEIGHTON 1940 E. M. Wise T. V. MOORE F. T. SISCO C. E. LA WALL W. R. CHEDSEY W. M. WEIGEL 1941 D. K. CRAMPTON E. A. STEPHENSON C. H. HERTY, JR. JULIAN E. TOBEY " PAUL M. TYLER 1942 CARL E. SWARTZ HARRY P. STOLZ E. C. SMITH NEWELL G. ALFORD A. F. GREAVES-WALKER B. L. MILLER

Jan 1, 1943

By W. F. Flanagan, K. R. Evans

The strong temperature dependence of the flow stress of bcc metals has prompted considerable interest and controversy concerning the rate-controlling influence of the Peierls' mechanism upon deformation in metals.18"21 Dorn and Rajnak" recently offered a criterion for Peierls' deformation utilizing a line-energy model of a dislocation to estimate the saddle-point activation energy, for the nucleation of a pair of kinks as a function of applied stress and the height and shape of the peierls9- barrier. It was found that Un/2Uk, where 2Uk is the excess energy of a kink pair, was a unique function of where is the effective stress and 7p is the Peierls' stress as defined in Fig. 20. The relationship found by Dorn and Rajnak between is given by the solid line of Fig. 21. may be expressed in terms of the temperature of test, T, and the athermal temperature, T,, defined in Fig. 20. Considering the strain-rate, 9, of deformation for a thermally activated process to be given by where fo is nearly a constant, it is seen that and the theoretical relationship of Fig. 21 may be examined with readily obtainable experimental parameters. Dorn and Coworkers analyzed a large amount of experimental data in this manner for materials sus-

Jan 1, 1967

By J. K. Edgar

FOR a number of years the production and use of super-purity aluminum (better than 99.99 pct) has been steadily increasing. High-grade lots of such aluminum show certain outstanding characteristics not found in lower grades containing principally silicon, iron and copper as impurities. One such characteristic is the so-called "self annealing," that is, the recrystallization of the heavily cold worked metal at room temperature.' Interest therefore is aroused as to the effects of the impurities. It is well known that the amounts of silicon and copper which occur in aluminum of better than 99.95 pct are completely soluble, at least at elevated temperatures (above 200°C). Iron, on the other hand, is known to be fairly insoluble in solid aluminum. Thus, a knowledge of the limits of this solubility would be of considerable use in studying the characteristics of the high purity metal. All investigators have agreed that iron has very low solubility in solid aluminum. Rosenhain, Archbutt and Hanson2 reported traces of an aluminum-iron phase in the "purest samples of aluminum obtainable." Gwyer and Phillips3 reported that an iron constituent was visible under the microscope in metal containing ".0088 per cent iron." Roth1 found that in the solid state the solubility of iron in high purity aluminum was 0.01, 0.01, 0.017 and 0.022 pct at 225, 320, 500 and 600°C respectively. Dix5 working with alloys containing less than 0.03 pct impurities, concluded from microscopic and chemical analyses of eutectic areas that the eutectic composition was close to 1.7 pct iron. Dix placed the eutectic temperature at 655°C'. Archer and Fink,6 using high purity aluminum-iron alloys, found that the hypoeutectic liquidus intersects the eutectic horizontal at 1.7 pct. This is in fair agreement with the investigation of the aluminum-iron system by Gwyer and Phillips who placed the eutectic at 1.89 pct iron with a freezing point of 653° PREPARATION AND CHEMICAL ANALYSIS OF ALLOYS Electrolytically refined aluminum (99.991 pct aluminum) and a high purity aluminum-iron alloy (11.45 pct iron) were used in the preparation of the alloys for this investigation. To aid in controlling the iron content of the experimental alloys, an alloy of lower iron content was prepared first from these materials. The high purity aluminum was melted and heated to about 700°C in a plumbago crucible coated with alundum cement and the aluminum-iron alloy was then added. The alloy was thoroughly stirred, fluxed and skimmed and then chill-cast into notch bars. The analyses of the three materials are given in Table I. The alloys for the determination of the solid solubility of iron in aluminum were prepared by melting 600 g total of the aluminum plus the required quantity of the aluminum-iron alloy (No. 92531). These

Jan 1, 1948

By M. E. Wadsworth, J. S. Cho

Colloidal silica dissolved in aqueous suspensions of high surface area thoria was permitted to adsorb on the thoria surface. Silica in three forms was identified by means of infrared spectroscopy and characterized by Si-O vibrational modes in the 9.0 to 10.5 region. A band at 9. 1 was attributed to free unad-sorbed silica, while adsorbed silica resulted in bands of greatest absorbency at 9.4 or 10.3p, depending upon the character of the surface bonding. Size considerations, the amount of silica adsorbed, and the character of the infrared spectrum for strongly adsorbed silica has been interpreted as evidence of formation of chain or layer silica linkages on the thoria surface. Infrared spectroscopy has been used successfully in recent years for the identification of minerals and synthetic inorganic substances. Unfortunately, infrared studies of silicate minerals have not proceeded to the point that unambiguous assignments may be made for Si-O vibrational modes as affected by lattice substitutions and structures. Several investigators have presented infrared spectra of silicate minerals, 1,7 and their work has pointed to the potential value of infrared to identify minerals as well as to note the sensitivity of various Si-O modes to structural and substitutional environments. The strong infrared absorption of various Si-O vibrational modes makes the infrared method a very useful tool for the study of silica adsorbed on the surface of solids of high surface area. Spaepen et a18 studied the adsorption of silica on thoria surfaces from aqueous solutions of silicic acid up to 300°C. A general review of the application of the infrared method to the study of surface adsorption has been presented by Pliskin and Eischens.9 EXPERIMENTAL Du Pont colloidal silica, Ludox SM (16.36% SiO2) and Ludox HS (30.25% SiO2) in aqueous suspensions were used as the sources of silica for the adsorption studies. The thoria used for this study was supplied by Union Carbide Nuclear Co.* under the preparation *Chemical Technology Div., Union Carbide Nuclear Co., Oak Ridge, Tenn. . number D-16-650. It was fired from the oxalate at 650°C and had a surface area of 32.4 ± 0.6 m2 per g measured by nitrogen adsorption. The chemical analysis of the D-16 thoria in ppm was: CO3= (5500), NO3- (< 4), so4±PO4 (100), and Si (20). The Ludox silica was placed in contact with the thoria in a two-liter autoclave10 between room temperature and 250°C. Slurries were made by placing 1 g of thoria in one liter of distilled water containing various additions of the silica sol. Samples were removed from the autoclave by opening a small stainless steel valve. Extracted samples were centrifuged for 10 min and excess solution was decanted. The sample was then dried for several hours at 80°C. Infrared samples were prepared by thoroughly mixing 10 mg of the thoria with 400 mg KBr in polystyrene vials on a "Wig-L-Bug" amalgamator. Pellets were pressed under vacuum and had final dimensions of 1.2 cm diam and 1.2 mm thick. Infrared spectra were

Jan 1, 1963

By Charles H. Moore

In the study of the properties of rutile pigments it became apparent several years ago that certain physical and optical properties could not be determined on particles of pigmentary size. Since reflected light is the dominant type which reaches the eye from small particles, the true color of pure rutile was not known. Most rutile pigments are acicular in habit, elongated parallel to the "c" axis. It was considered important to know the nature and tone of light transmitted, for example, by a basal plate. Further, as shown by spectrophotometric curves, there is a very strong absorption of light of 4000 k as measured on particles with random orientation. It would be interesting to see whether this absorption position varied with predetermined and selected orientations. Also, since the behavior of titanium pigments in a vehicle is important, a knowledge of the surface wettability of single crystals by various media should prove very fruitful. Finally, the optical properties of rutile are such that it should show, in a single pure crystal, greater fire and brilliance than the diamond. Mineralogists had long speculated that this would be the case and curiosity was strong to produce a single crystal large enough to cut.

Jan 1, 1949

By R. P. Rothwell

THE milling of silver ores has arrived at a great degree of perfection in the mining districts of our Western States and Territories, and I have thought the record of the practical results obtained at the present time, in a few of the principal districts, would prove of value and interest to many of our members, both at home and abroad. An American silver mill is composed, in descending order from where the ore is dumped, of: 1st. A rock-breaker, usually of the Blake or Alden pattern ; 2d. The battery of stamps, the number of which varies from 5 to 120, generally in batteries of 5 or 10 heads, so arranged that a single battery may stand while the others are running; 3d. The tanks where the crushed ore settles (if it is a wet stamping-mill), or of a drying-floor if the crushing is done dry; 4th. Amalgamating pans ; 5th. Settling pans ; 6th. Agitators or pans in which mercury escaping in the tailings is caught; 7th. Blanket sluices, over which the tailings run, and where mercury and unamalgamated sulphides are saved. A reference to the engravings (see plate), which show one of the latest forms of an 80-stamp silver-mill run by a turbine water-wheel, will show clearly the arrangement of the several parts. THE ONTARIO, UTAH, SILVER MILL. One of the best examples of a silver-mill, and at the same time one of the most successful concerns in the West, is the mill of the Ontario Silver Mining Company, near Salt Lake, in Utah. This mill treats the ore from the Ontario mine, ore which at present is very base, being composed of zinc, lead, and silver sulphides and silver chloride in a quartz gangue. This ore has become baser as the mine attained greater depth, though the vein holds its own, or rather increases, both in thickness and richness. The mill is man¬aged in a skilful and economical manner, though the necessity for * Read at the Montreal meeting, September, 1879.

Jan 1, 1880

Jan 1, 1925

By J. C. Yannopoulos, N. J. Themelis

Ah electronic thermogravirnetric balance was used to measure the veductioiz rule o single cirpric oxide particles suspended in a stream of hydrogen. Very jzne thermocouples embedded in lie center and at the surface of the sphere recorded the variation of terw perature during reduction. In contrast to iron oxide reduction, where in most instances the rate of interface reactiokl is controlling, the heat- and mass-transfer phenotnena play a predolrinant role in the reduction of cupric oxide. The correlation of experitnental data or tnass lransfev lhrough the boundary layer at Reynolds nunlber 0-4 50 was as jollocs: ThE reduction of cupric oxide by hydrogen is represented by the equation: It is a highly exothermic reaction and the amount of heat released varies only slightly with temperature (-21,430 cal per g-mole at 400°C). Most of the published studies on this system have been conducted at temperatures in the range of 34 to 280c.l-&apos; The concensus of opinion has been that at temperatures below 200°C the reaction is preceded by an induction period during which there is very little or no reduction. The length of this period diminishes as the temperature of the reaction is increased1l5 and aseawa found that at 280°C reduction starts practically immediately when the oxide is exposed to hydrogen gas. The existence of an induction, or incubation, period has led experimenters to believe that the reduction of CuO by hydrogen is catalyzed by metallic copper.&apos; Boldurev and rmolaev found that mechanical additions of powdered copper to oxide did not affect its reduction, although metallic copper produced during the reduction seemed to have a catalytic effect. At least three other authors2&apos;5&apos;7 have reported that addition of copper had no effect on the rate of reduction. Pease and alor&apos; observed that water vapor had a strong inhibiting effect on the reduction at 1503C, but its effect was greatly diminished at 200 C. Pavlychenko and Rubinchik5 studied this reaction at 159 to 235 C and found that, once the reaction had been initiated, there was no inhibiting effect due to the introduction of water in the hydrogen stream; at temperatures above 183°C there was no inhibiting effect due to water vapor, either before or during reaction. The same authors noted that the rate of reduction was independent of pressure in the range of 200 to 700 mm Hg. aseawa investigated the kinetics of the CuO-Hz system at 160 to 280°C and estimated the apparent activation energy at 14,000 cal per g-mole. A similar value (13,500 1200 cal per g-mole) was reported by ond&apos; in the temperature range 148 to 216°C. Bond also reported that there was no incubation period and that water vapor had no inhibiting effect on reduction at temperatures above 190 C. The above studies have been conducted at temperatures below 280°C and the physical configuration of the system under investigation has not been defined adequately. However, it is well-known that the mechanism of gas-solid reactions depends on a number of in series physical and chemical rate prcesses.&apos;&apos; It is, therefore, essential to include among the experimental factors the geometry of the solid system and the mass-transport characteristics of the reducing gas. Scott studied the reduction of packed beds of cupric oxide cylinders by Hz-He streams of very low hydrogen concentrations at temperatures 400 to 600 C, pressure of 10 to 30 atm, and gas velocity from 0.18 to 5.8 ft per sec (3 < Rep < 30). The reduction rate was found to be mainly controlled by diffusion through the boundary layer and through the pores of the reduced copper phase. The following correlation was proposed: Scott in an earlier work studied the reduction of fixed beds of cupric oxide wire and found that the rate of flow of the gas stream through the bed had a controlling effect on the rate of reduction. The same mass-transfer phenomenon was observed by Bond and clark13 on a similar reduction system. The analogy between mass and heat transfer through the boundary layer which exists between a solid surface and the bulk stream stems from the similarity of the differential equations representing these phenomena

Jan 1, 1967

By W. G. Sinclair

THE North Texas district presented in this paper includes the counties of Archer, Baylor, Clay, Cooke, Foard, Hardeman, Jack, Knox, Montague, Wichita, Wilbarger and Young. It corresponds with the Texas Railroad Commission&apos;s district No. 9. Table I conforms with the nomenclature of pools as designated by the Commission. Most of the oil and gas produced in this region, generally referred to as the Red River uplift, comes from the Pennsylvanian strata. In recent years, however, increasing amounts are being developed in both the Mississippian and Ordovician.

Jan 1, 1946