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By R. F. Rolsten

VAN Arkel 1 prepared ductile tantalum by the thermal decompoiition of tantalum pentachloride on a resistively heated wire (2000° C) in an evacuated bulb maintained at 100°C. Burgers and Basart2'3 observed the formation of a mixture of tantalum carbide and free metal when a carbon deposition base was used. campbel14 suggested the thermal decomposition of the iodide if a lower decomposition tem- perature was desired. To date, the details for preparing high-purity iodide tantalum have not been disclosed. EXPERIMENTAL The tantalum to be purified was symmetrically placed around the clear quartz deposition surface centrally located within a 64 mm cylindrical Vycor bulb. The deposition vessel usually employed5 was modified6 by incorporating a reentrant fin,mer in place of the customary metal filament in the head

Jan 1, 1960

By AIME AIME

SECOND only to the February Annual Meeting of the Institute are the Regional and Divisional meetings held in the fall of each year. Six such gatherings are scheduled in the next the months, with something likely to interest every member of the Institute. A brief résumé of the programs follows. Regional Meeting Vancouver T HE regional meeting of the Institute will be held at Vancouver, Sept. 13 to 20, in conjunction with the annual western meeting of the Canadian Institute of Mining and Metallurgy. The pro gram appeared on page 350 of MINING AND METALLURGY for July and-proof of careful preparation-a month later re- quires no correction and little elaboration. On the technical side there are few changes. A new item on the Wednesday morning program is the paper, "Investigation of Residential-type Stokers," by H. F. Yancey, supervising engineer, Northwest Experiment Station. U. S. Bureau of Mines, Seattle. As to entertainment the meeting is taking on some most pleasurable aspects. Two notable excursions have been arranged.

Jan 1, 1937

By Arthur L. Hall

The purpose of this symposium is to challenge industry to better air classification, and as a first step toward fulfillment, to spotlight three fairly recent, aerodynamically designed, highly efficient air classifiers. This discussion does not intend to imply that present practice is bad. Actually, when present air separators are used for the jobs for which they were originally designed, they give high production and uniform operation, with a minimum of maintenance. The customers of nonmetallic mineral pigment producers, however, are making increasing demands for finer products, such as 99.9 pct -20µ, which appears to be beyond the economic capabilities of standard air separators industrially used over the last 10 to 30 years. Here is an actual example. A 10-ft diam pebble mill is in closed circuit with a conventional 12-ft diam centrifugal air separator, grinding 20-mesh wollastonite to a series of fine grades up to 99.97 pct - U.S. No. 325 mesh (44µ). Fig. 1 shows variations in fineness of mill discharge (or air separator feed), recycle for regrinding (or air separator tails), and product as measured by a wet rotating sieve test. For example, when the mill is turning out a product 80 pct -325, the mill discharge or separator feed is 30 pct -325, and the coarse tailings or recycle is only 5 pct -325. Hence 25 pct of the 30 pct available is accepted as product. This is efficient separation, and the ratio of recycle to feed is only about 2: 1. How- ever, to make a product testing 99.97 pct -325 the separator feed is 62 pct -325 and the coarse tailing 60 pct -325. In this case the recycle ratio is about 13: 1 and the economic limit to produce fineness has been substantially reached with this given equipment and process arrangement.

Jan 10, 1957

By W. H. Yarroll Discussion by W. A. Griffith

W. A. Griffith (Head, Research Department, Phelps Dodge Corp., Morenci, Ariz.) - It is gratifying to see the increasingly common use of classical statistical procedures by metallurgical researchers. Mr. Yarroll has given excellent illustrations of the utility of multiple correlation analysis of complex metallurgical data. Our experience in applying these procedures to historical plant operating data has differed, however, from that which he suggests. The uninitiated frequently assume that the volumi-

Jan 1, 1969

By E. T. Turkdogan

Jan 1, 1962

Organization Place Date 1919 American Society of Mechanical Engineers... New York, N. Y. Dec. 2-5 American Institute of Chemical Engineers.... Savannah, Ga. Dec. 3-6 Geological Society of America..: Boston, Mass. Dec. 29-31 American Society of Heating and Ventilating 1920 Engineers New York, N. Y. Jan. Mining and Metallurgical Society of America.. New York, N. Y. Jan. 13 American Institute of Min. and Met. Engineers New York, N. Y. Feb. 16-19 American Ceramic Society Philadelphia, Pa. Feb. 23-26 American Electrochemical Society Boston, Mass. Apr. 8-10* *On Apr. 9, a joint meeting will he held with the A. I. E. E.

Jan 12, 1919

By Earl Bardwell

THE determination of suitable and safe annealing temperatures is one of the most important problems arising in the operation of a copper rolling mill. Certain of the larger mills have worked this problem out for themselves and in these mills the operation has become more or less standardized. In some of the mills pyrometers are used to measure the temperature of the annealing furnaces and careful watch is kept to see that overheating does not take place. In a considerable number of the mills, however, dependence is placed entirely on the judgment of the operator. The almost total lack of literature bearing on this subject seems sufficient warrant for the publication of this paper. The discussion of this subject naturally divides itself into two parts: (1) The effect of annealing temperature on physical properties; and (2) changes in the microstructure of refined copper due to cold rolling and annealing. I. THE EFFECT OF ANNEALING TEMPERATURE ON PHYSICAL PROPERTIES For the purpose of investigating this phase of the subject six test bars were selected, varying in oxygen content between the limits of 0.036 and 0.070 per cent. The chemical composition of each of these test bars was as follows:

Jan 8, 1914

By Howard H. Fields

Any mining engineer with a desire to operate independently, with some financial backing, and with no fear of heavy responsibility and long hours, should be able to make a comfortable living in Mexico. Barring a few inconveniences such as a lack of satisfactory liability or accident insurance, the difficulty of obtaining repair parts or vehicles, and the length of time required to receive returns from shipments, the operation of small mine is not at all difficult. It is, in fact, a little easier to find a good prospect in Mexico than in the U.S.

Jan 1, 1950

By W. D. Johnston, T. P. Thayer

THE minerals that collectively are known as chromite form an isomorphous series of the general formula (Mg,Fe) 0. (Cr,Al,Fe) 203. So wide is the range in chemical composition in this group that chrome ore consisting entirely of the mineral chromite may range from less than 30 pct to more than 60 pct Cr203. The most comprehensive published data on the chemical com- position of chromite are by Stevens,62 who made complete analyses of 52 samples of chromite concentrate from many localities in North, Cen- [ ] tral, and South America. These samples were mechanically purified to remove associated silicates and might be regarded as the cleanest chromite that could be obtained by any mechanical milling process. Fig 1 shows the predominant zone of isomorphism, within the triangular prism of composition defined by the mineralogical end members of the series, wherein his analyzed samples fell.

Jan 1, 1949

By F. D. Richardson

STAFF: Editor, Gerhard Derge Carnegie lnstitute of Technology Schenley Park Pittsburgh, Pa. 15213 Editorial Assistant, M. A. Redmerski Production Editor, Otto T. Johnson THE METALLURGICAL SOCIETY: Jack H. Scoff, President; Richard C. Cole, Past-President; Harold 0. Emerick, President-Elect; Ralph L. Hennebach, Treasurer; Robert W. Shearman, Secretary; Donald A. Parks, Assistant Secretary; Leslie S. Wilcoxson, Assistant Secretary. PUBLICATIONS COMMITTEE OF THE METALLURGICAL SOCIETY: R. E. Lund, Chairman; T. E. Dancy, H. O. Emerick, P. R. Gouwens, R. E. Grace, J. H. Jackson, H. H. Johnson, A. E. Lee, Jr., R. R. Nosh, R. D. Pehlke, and Paul Queneau. Review and selection of manuscripts is under the supervision of the following Publications Committees: Extroctive Metallurgy Division: R. E. Grace, Choirmon; G. M. Bell, D. W. Bridges, J. M. Cigon, G. W. Heoly, T. A. Henrie, R. D. (Holli-doy, C. E. O'Neill, C. S. Somis, A. W. Schlech-ten, and Charles Shull. Iron and Steel Division: R. D. Pehlke, Choirmon; T. P. Floridis, Arnulf Muon, G. R. St. Pierre, E. T. Turkdogan, L. H.Von Vlock, and J. M. Uys. lnstitute of Metals Division: H. H. Johnson, Jr., Chairman; J. B. Clark, Vice Choirmon; M. R. Achter, G. F. Bolling. J. O. Brittoin, G. P. Conard, II, R. S. Davis, L. A. Girifolco, G. T. Hohn, J. P. Hirth, L. Himmel, G.T.horn, George Krauss, J. D. Livingston, R. D. Manning, H. M. Otte, S. V. Rodcliffe, R. E. Reed-Hill, H. C. Rogers, E. ScaIa, O. Sherby, M. T. Simnad, G. R. Speich, E. A. Steigerwald, R. A. Swolin, W. A. Tiller, W. R. Upthegrove, J. B. Wagner, Jr., Derek Wolton, H. W. Weart, W. W. Webb, and D. Published seven times yearly in February, March, April, June, August, October, and December by the American lnstitute of Mining, Metallurgical, and Petroleum Engineers, Inc., 345 East 47th Street New York, N. Y. 10017. Telephone PLAZA 2 -6800. Subscription $30 per year for non-AtME members m United States and North, South, and Central America; $32, foreign; $7.50 for AlME members Single copies, $6.00, single copier foreign, $6.50. The AiME is not responsible for any statement made or opinion expressed in its publications . . . Copyright 1964 by the American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. . . . Registered cable address, AiME New York Indexed in Engineering Index, Industrial Arts Index, and Chemical Abstracts. Second dost postaas poid ot New York, N. Y.,ond Ann Arbor, Mich. Volume 230, Number 6.

Jan 1, 1964

By R. E. Gilchrist, R. F. Nielsen

When a gas is displaced by mother in a porous medium, and there is a relative immobile liquid present. there is a transition zone in which the gas composition varies from essentially that of the original gas to that of the injected gas. The change in extent of this zone with time may be governed by a mixing process in the direction of flow and by the rate of establishment of gas-liquid equilibrium, if the gases are appreciably soluble in the liquid. The relative importance of these two factors in deterri~ining the growth of the transition zone is discussed, with appropriate equations and experimental data. INTRODUCTION The various solution methods of oil recovery involve a transfer of the components of a mixture, whether within a single phase or between a liquid and gas. The similarity of a natural porous medium to systems used in separation and chromatographic processes makes it seem reasonable that certain concepts used by chemical engineers in "mass transfer" might be applicable to petroleum reservoirs. One approach, the HETP (height equivalent to a theoretical plate), involves a distance or length of time over which equilibrium might be con. sidered as established. Another approach involves direct use of a rate of mixing or rate of establishment of equilibrium. The latter approach has been preferred in relation to production problems. DISCUSSION AND PROCEDURE When a gas or liquid in a porous medium is displaced by one of different composition but miscible with it there will be set up a transition zone in which the composition varies from cssentially that of the original fluid to essentially that of the injected fluid. If the fluid being displaced is a gas, and there is a relatively immobile liquid present, the transition zone may be

By H. O. McLeod, J. M. Campbell

Data analysis of pentane and hexane adsorption from natural gas in a fixed bed of silica gel shows that constant length mass transfer zones form, the curvature of the adsorption isotherm controls the growth of the mass transfer zone and surface diffusion of molecules inside the silica gel particle controls the mass transfer rate. Curvature of the hexane isothem is more than the curvature of the pentane isotherm. Because of this curvature the hexane adsorption zones reached a constant length. In contrast, the pentane adsorption zones were always increasing in length during each run. A procedure was developed to obtain correct mass transfer coefficients using effluent curve slopes. These transfer roefficients increase with the amount of hydrocarbon adsorbed on the silica gel particle. The characteristic shape of the hexane effluent curves also show that molecular diffusion inside the silica gel particle controls the adsorption rate of pentane and hexane. INTRODUCTION The purpose of this study was to determine the mechanisms that control the dynamic adsorption of hydrocarbons from a natural gas onto silica gel. Before one can deal effectively with multicomponent adsorption, the transfer mechanisms by which a single hydrocarbon component is adsorbed from the gas stream must be defined. Two principal investigations of this system have been published ' and indicate that diffusion through the gas around the particle controls the adsorption rate. Some of the experimental observations in each study either do not support this transfer mechanism or are inconsistent with the mathematical model used in analysis. In this study surface diffusion of molecules inside the particle controls the mass transfer rate of pentane and hexane. This mechanism is indicated by the effluent curve shape for a constant length transfer zone and by the variation of the mass transfer coefficient with concentration of the adsorbed hydrocarbon. THEORY AND DEFINITIONS — MATHEMATICAL MODELS Mathematical solutions for the isothermal adsorption of a trace component from a carrier gas are derived from three relationships: the mass balance or continuity equation, the equilibrium relationship between the gas and solid phases, and a mass transfer rate equation. The transfer rate is proportional to the adsorbate concentration gradient within either the gas or solid phase. Mathematical solutions of these equations usually give the adsorbate concentration as a function of time and distance from the bed inlet. That part of the bed in which the adsorbate concentration changes from a maximum to a minimum value is called the transfer zone. This transfer zone is directly related to a plot of the effluent concentration vs time which has a characteristic S-shape. This general shape is determined by the continuity equation and occurs in many processes of diffusional transfer.

Jan 1, 1967

By V. H. Whihelm

Since 1935 California has enjoyed a remarkable cycle of discovery, which has placed the state in a very satisfactory position in regard to oil reserves. Most ol the geophysical plays have been drilled and it is possible that new discoveries must be made by the application of careful geologic and stratigraphic studies. During 1940 only one new field was discovered, which, although not of major importance, may lead to additional discoveries. During the year, 113 wildcats were drilled. New discoveries, extensions and a reappraisal of discoveries made in 1939 will not approximate over 50,000,000 bbl., as against an estimated withdrawal during the year of 224,000,000 barrels. Demand in terms of crude for 1940 was 632,000 bbl. per day as against 626,000 bbl. per day for 1939. Demand for gasoline was the same as in 1939, but the demand lor fuel oil increased 3.8 per cent. Compared with 1939, Japanese shipments decreased from 75,786 bbl, per day to 61,000 bbl. per day, but the balance of Pacific foreign shipments increased from 59,409 bbl. per day to 61,304. Total with-drawals from storage during the year will approximate 7,000,000 bbl., almost all of which is fuel oil. Drilling activity was slightly greater than in 1939 and accounted for 890 new producing wells as against 851 for 1939 (Table 3). Production averaged 611,900 bbl. per day as compared with 614.,842 bbl. per day for 1939. The productive acreage figure of the state was increased by 4000 through discoveries and extensions. New Discoveries Los Angeles Basin District Del Vdle Field.—Northwest of Newhall, where the first oil well in California was drilled, R. E. Havenstrite completed his Lincoln No. I well, flowing 390 bbl. of 50" gravity oil together with 7000 M CU. ft. of gas. Later the well was recompleted, after cutting off the gas, for 950 bbl. of 34" gravity oil. The type of structure from which this production is coming is a plunging anticline, complicated by faulting. The Lincoln No. I well uncovered approximately 180 ft. of net sand. This field contains a gas cap and its indicated productive area approximates 500 acres. An intensive wildcat drilling campaign is expected during this coming year in the district in the vicinity of the Del Valle field. Extensions and Deeper Sand Developments Los Ange1es Basin District Athens Field.—On the northwest plunge of the Athens structure, the Thorley Oil Co. completed its No. 12-1 well, flowing 250 bbl. of 3 2" gravity oil from a depth of 8097 ft. The area in which the well is located is complicated by faulting and it is impossible at this date to determine the importance of this deep-zone discovery.

Jan 1, 1941

By V. H. Whihelm

Since 1935 California has enjoyed a remarkable cycle of discovery, which has placed the state in a very satisfactory position in regard to oil reserves. Most ol the geophysical plays have been drilled and it is possible that new discoveries must be made by the application of careful geologic and stratigraphic studies. During 1940 only one new field was discovered, which, although not of major importance, may lead to additional discoveries. During the year, 113 wildcats were drilled. New discoveries, extensions and a reappraisal of discoveries made in 1939 will not approximate over 50,000,000 bbl., as against an estimated withdrawal during the year of 224,000,000 barrels. Demand in terms of crude for 1940 was 632,000 bbl. per day as against 626,000 bbl. per day for 1939. Demand for gasoline was the same as in 1939, but the demand lor fuel oil increased 3.8 per cent. Compared with 1939, Japanese shipments decreased from 75,786 bbl, per day to 61,000 bbl. per day, but the balance of Pacific foreign shipments increased from 59,409 bbl. per day to 61,304. Total with-drawals from storage during the year will approximate 7,000,000 bbl., almost all of which is fuel oil. Drilling activity was slightly greater than in 1939 and accounted for 890 new producing wells as against 851 for 1939 (Table 3). Production averaged 611,900 bbl. per day as compared with 614.,842 bbl. per day for 1939. The productive acreage figure of the state was increased by 4000 through discoveries and extensions. New Discoveries Los Angeles Basin District Del Vdle Field.—Northwest of Newhall, where the first oil well in California was drilled, R. E. Havenstrite completed his Lincoln No. I well, flowing 390 bbl. of 50" gravity oil together with 7000 M CU. ft. of gas. Later the well was recompleted, after cutting off the gas, for 950 bbl. of 34" gravity oil. The type of structure from which this production is coming is a plunging anticline, complicated by faulting. The Lincoln No. I well uncovered approximately 180 ft. of net sand. This field contains a gas cap and its indicated productive area approximates 500 acres. An intensive wildcat drilling campaign is expected during this coming year in the district in the vicinity of the Del Valle field. Extensions and Deeper Sand Developments Los Ange1es Basin District Athens Field.—On the northwest plunge of the Athens structure, the Thorley Oil Co. completed its No. 12-1 well, flowing 250 bbl. of 3 2" gravity oil from a depth of 8097 ft. The area in which the well is located is complicated by faulting and it is impossible at this date to determine the importance of this deep-zone discovery.

Jan 1, 1941

By Francis T. Freeland

In the West many precious-metal mines are worked in patches by lessees, under conditions which closely resemble those of what is called " tribute-work" in Cornwall.* The company has its own foreman or inspector, and usually employs the engineman, blacksmith, pumpman, and perhaps other general workmen. As an inducement to work on a new piece of ground, where no ore is in sight, the company may advance a " footage"

Jan 1, 1896

By John Chipman, Wayne L. Worrell

Using recent thermodynamic data for the carbides and oxides of tantalum, columbium, and vanadium, the stable solid phases aboue 1300°K and at 1 atm CO(g) pressure in each M-C-O system have been determined. Pourbaix-Ellingham diagrams have been constructed and are used to estimate the minimum temperatures necessary to obtain these metals by carbothermic reduction under reduced pressures. TANTALUM, columbium, and vanadium react with carbon to form the M,C and MC carbide phases. The M,C carbides have narrow homogeneity ranges, but the MC phases possess considerable ranges of homogeneity.' The free energies of formation of the MC carbides were recently measured, and those of MC and M2Ccarbides have been estimated., (The notations MC and MC denote, respectively, the carbide compositions at the carbon-rich and at the metal-rich boundaries of the homogeneous MC phase.) In this paper, these carbide data are combined with thermodynamic data for the oxides to predict the stable phases in the Ta-C-O, Cb-C-O, and V-C-O systems at specified temperatures and oxygen pressures. M-C-O PHASE DIAGRAMS The solid phases in equilibrium above 1300°K for each M-C-0 system are shown in Figs. 1, 2, and 3. Above 1300°K, the vapor would consist entirely of carbon monoxide; and these phase diagrams were obtained by specifying the vapor pressure of CO(g) to be 1 atm. The temperature at which any two solid phases become unstable is specified along the two-phase equilibrium lines in each diagram. To simplify the diagrams, all solid phases in the Ta-C-O and Cb-C-O systems are represented as stoichiometric compounds. However, the homogeneity ranges of VO and VC are indicated, because they form a complete series of solid solutions.3 It also should be noted that the homogeneity range of

Jan 1, 1964

By H. L. Hazen

THIS is the story of the recent operations of the Standard Cyaniding Co., which owns the Standard mine, a low-grade gold property in sight of Highway 40 about thirty miles from Lovelock toward Winnemucca, Nev. The ore is mined by power shovel and cyanided after grinding to only 3/S in. A total direct cost of $1.24 was attained in 1941 on 600 tons a day. Mining operations ceased, under Government edict, in 1942, and only in recent months have been resumed. The operating difficulties of today are: (1) the high cost of supplies; (2) labor problems; and (3) Federal laws as interpreted and enforced by executive bureaus of the Government. Of these, the increased cost of supplies is the least important.

Jan 1, 1947

By T. R. A. Davey

The fundamental principles by which bismuth may be removed from lead by pyrometallurgical processes are enumerated. Qualitative discussion of the phase diagrams concerned is followed by presentation of quantitative diagrams. Brief mention is made of the practical aspects. Data presented show how chemical lead (<0.005 pct Bi) may be produced by the Jollivet, Dittmer, and Kroll-Betterton processes. BISMUTH is an element whose properties are very similar to those of lead, and its minerals are associated to a greater or lesser extent with nearly all the major lead ore deposits of the world. In consequence, the lead produced contains bismuth unless a special debismuthizing process is practiced. There does not appear to be any published comprehensive review of the effect of bismuth as an impurity on the properties of lead, and there is some uncertainty as to the beneficial or detrimental effects of small amounts of bismuth in lead used for particular applications. Standard specifications of most countries stipulate a maximum bismuth content of 0.005 pct for chemical lead. With one exception, this specification is met only by lead producers whose ores are relatively bismuth-free, or whose refineries are electrolytic. In lead for certain applications a higher bismuth content is preferred by some fabricators.&apos; In contrast to the refining for silver, copper, and antimony, the refining for bismuth does not usually result in a large overalil economic gain from the sale of byproduct. Thus, debismuthizing is customarily practiced only if market conditions demand a lead with a bismuth content lower than that produced by classical refining; i.e., softening, desilverizing, and zinc refining. Until this century, debismuthizing was carried out only a:; an incidental result of desilverizing, as later described. This century has seen the development of the Betts electrolytic process—the only successful one of many electrolytic processes proposed and patented —and a number of precipitation processes based on the pioneering work of Kroll,&apos; although only one of these, the Kroll-Better ton process,&apos; is in wide commercial use today. It is proposed in this paper to deal only with the pyrometallurgical processes, excluding those based on aqueous electrolysis. Historical Background Prior to 1833 silver (and incidentally bismuth) could not be removed from lead. To recover silver from rich bullion, the only course available to lead refineries was to cupel the bullion, forming a slag of litharge. The first slag tappings or skimmings, on reduction, yielded soft lead of very low silver and bismuth contents. Intermediate skimmings yielded a lead of somewhat higher silver and bismuth contents, which could if desired be recupelled. The last skimmings yielded a litharge very high in bismuth, which could by successive oxidation and reduction cycles be separated into high purity bismuth, and lead returns. This oxidation reduction process, with modern operating techniques, can still be used today to produce a portion of a lead refinery&apos;s output of very low bismuth content, as discussed later. In 1833 Pattinsone discovered that lead bullion could be purified of silver and bismuth by fractional crystallization, the primary lead crystals formed by partial freezing being purer than the melt. Repeated processing in pans produced a lead containing as little as 0.02 pct Bi. The simple explanation of this

Jan 1, 1957

By Eugene R. Rice

There are many methods for determining the meridian, but all of those in common use involve at least two separate observations, one for latitude and one for azimuth. Such observations made upon a south star at any hour are open to the objection of possible inaccuracy due to ignorance of the absolute refraction, and also to slow change in the altitude of the star when near the meridian. The method of observing a circum-polar star at elongation. besides requiring a separate observation for latitude, is open to the serious objection that clouds may obscure the star at the critical moment. Moreover, a tedious wait for the star to come to elongation is sometimes necessary. Many of us can recall &apos;long, cold, weary vigils, waiting for Polaris to reach elongation. For observing a circumpolar star at any hour, not only the latitude, but also the true time, must be known. This it is practically impossible to obtain, except in regions reached by the telegraph, and usually then one has to know the longitude also, in order to reduce " standard time" to " local time." The results obtained by this method, when the star is at culmination, are not very good, unless the true local time is absolutely known. The methods of obtaining the nleridian from the sun, by means of a solar attachment, or by direct observation, while good, are not absolute, by reason of refraction, change in declination of the sun, and small change in vertical angle, when the sun is near the meridian. For these two methods, latitude, time, and approximate longitude have to be known. In the method here described, only one observation is needed, and from it are computed azimuth, latitude, aud sidereal time. In other words, one call observe a circumpolar star—Polaris

Jan 1, 1911

Jan 1, 1959