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By W. T. Turrall, M. J. Cook

A discussion of modern developments in beneficiation of fine sizes of anthracite, this paper includes a description of the plant flowsheet, an analysis of operating results, and a summary of fundamentals of mineral separation relative to plant operation.

Jan 9, 1953

By C. B. Alcock, M. G. Hocking

The kinetics of the growth of sulfate layers on blocks of Cu20 has been studied between 688" and 800°C. At 788c the over-all weight increases followed the parabolic rate law, with k = 216 30 sq mg per cm4 min, using a 1:1 entering gas mixture of SO2:02. At 757 after an initial linear period the parabolic rate law was followed, with k = 57.8 10 sq mg per cm4 min. The gas mixture required a platinum catalyst to produce the maximum SOs pressure. The sulfation rate at 757' and 788c was high until all the CUZO had changed into a core of CuO, when it became very much lower. At 757°C marker experiments showed that the sulfates (CuO. CuS04 and CuSO4) grow outwards from the oxide surface, but CuO. CuS04 mixed with CuO was found beneath the markers. At 688 markers were found at the CuO. CuS04/CuS04 interface. Visual observations at 757 showed a liquid eutectic moving beneath the sulfate surface. causing very rapid sulfation and extruding to solidify as thick 'needles" up to 8 mm long. Marker experiments have shown conclusi.cely that CuO grows on Cu20 in air by the outward migration of copper. ThermODYNAMIC measurements on the sulfate and basic sulfate of copper, reported recently,' are followed here by measurements of the rates of formation of these sulfates on cuprous oxide, in order to provide a background for the understanding of roasting processes. peretti2 and McCabe and Morgan3 have shown that the phase Cu20 lies next to Cu2S when the sulfide is roasted under conditions where sulfates will be formed. Since this would present too complex a system for kinetic study, the present work4 has been based on the kinetics of sulfation of the oxide phase. The results of a study of the kinetics and mechanism of the sulfation of cobaltous oxide have recently been reported.4,5 Results on the sulfation of cuprous oxide have also appeared,6 but are at variance with those to be reported here. This seems to be because the previous workers6 did not obtain constant SO3 pressures from the SO2/O2 sulfating gas mixtures used, as will be discussed later. Wadsworth, Leiter, Porter, and Lewis found that the sulfates produced when SO2/O2 mixtures are passed over Cu20 at red heats are CuS04 and the basic sulfate CuO.CuSO4. When the decomposition of CuS04 was followed' by differential thermal analysis, a stage corresponding to CuO .CuS04 was reached before decomposition into the oxide occurred. APPARATUS The vertical furnace used for quantitative studies was a conventional resistance-heated and propor- tionately controlled furnace with an even zone (1 deg) which was 4 cm long. The gas mixtures of SO2 and 02 were made by mixing measured flows from capillary flowmeters and drying over phosphorous pentoxide before passing them into the Pyrex top-piece of the furnace assembly. A mullite tube of bore 2% cm was used as reaction vessel and at the bottom of this tube was a trap for SO3, which condensed as a colorless liquid. The residual gas was led into a fume cupboard for ventilation to the atmosphere. The furnace used for visual observations of needle growth and other phenomena consisted of a transparent silica reaction tube of bore 3 cm, having an optically flat silica window sealed into its wall. The reaction tube was clamped vertically, inside a mullite tube of bore 4 cm and length 42 cm which was heated by Kanthal windings. The window in the silica reaction tube was arranged opposite a hole 3 cm wide and 2 cm tall which had been cut in the wall of the mullite winding tube 19 cm from its top end. A binocular microscope was used to look through the window, illumination being provided by a focusing microscope-lamp offset sideways and downwards. The oxide block to be sulfated was suspended from the removable Pyrex top-piece to the reaction tube, by means of which it was inserted at the start of the experiment, and through which entered the S02/02 gas mixture. The variation of the temperature inside the reaction tube with horizontal and vertical displacement from the window was investigated, and, while it can be said that the temperature was constant 1 deg, its value at a given position was known only to 12 deg. In both furnaces, the oxide block to be sulfated was suspended from a small silica hook immediately downstream from a platinum thimble used as catalyst, which was held on a long silica rod from a Pyrex spring attached to the removable Pyrex top-piece of the furnace. The spring was only included in the quantitative sulfating furnace; its sensitivity was 1.4 cm per g and it was found to be free from creep in a 16-hr test when carrying the working load. The extensions were followed by a cathetometer which could be read to 0.001 cm, corresponding to i0.7 mg. Extensions of the spring were measured on adding weights between 5 and 500 mg to the working load (thimble + oxide block), and Hooke's law was closely obeyed. SAMPLES Cuprous oxide blocks were prepared by oxidizing Johnson Matthey "Specpure" copper sheet of 1 mm thickness (impurities: iron at 3 ppm, silver at 2 ppm, lead, nickel, sodium, and silicon each at 1 ppm, calcium, chromium, magnesium, and manganese each at less than 1 ppm) for 6 days in air at 1000°C in a re-crystallized alumina boat. It has been reported7 that when Cu20 is prepared by heating copper sheet for 1 day the central plane of the blocks produced consists

Jan 1, 1967

By EDWARD B. DURHAH

The illustration Fig. 12, of the paper of Edward B. Durham, "Electrolytic Refining at the U. S. Mint, San Francisco, Cal.," printed in Bulletin No. 58, October, 1911, p. 830, contained an error. The corrected diagram is printed below.

Nov 1, 1911

[Officers and Committees of the Society of Petroleum Engineers 1 Officers and Staff of the AIME 2 Officers of AIME Sections Predominantly Petroleum in Membership 3 Alphabetical List of Members 5 Geographical List of Members 106 Advertisers' Index 128]

Jan 1, 1961

By R. S. Wagner, W. G. Pfann

METHODS that have been used to measure stress relaxation in metals and plastics have been reviewed recently by G. R. Gohn and A. FOX.' The ideal stress relaxation test comprises placing a sample under a constant strain (usually considered

Jan 1, 1962

By D. J. Sellmyer

In order to orient single crystals by the back-reflection method it is necessary to know the angles between the various crystallographic planes. These angles have already been published for the hexagonal close-packed metals magnesium, zinc, and cadmium.'

Jan 1, 1965

[Officers and Committees of the Society of Petroleum Engineers 1 Officers and Staff of the AIME 2 Officers of AIME Sections. Predominantly Petroleum in Membership 3 Alphabetical List of Members 5 Geographical List of Members 95 Advertisers' Index 122]

Jan 1, 1961

Freeport's Floating Mine Begins Sulphur Operation Eight years of research were culminated when Freeport Sulphur Co.'s floating mine plant went into operation on Bay Ste. Elaine in the remote Louisiana bayou country 60 miles southwest of New Orleans.

Jan 1, 1953

By D. W. Fuerstenau, S. Raghavan

This paper presents a brief summary of some of the thermo- dynamic aspects of flotation processes. Thermodynamic considerations that control interfacial and wetting behavior in mineral/water/air systems are discussed. Particular attention is given to the thermodynamics of collector adsorption.

Jan 1, 1976

The amendment to Article III, Section 1, of the Constitution, raising the dues from $10 to $12 a year commencing in 1917, which was submitted to the members for letter ballot, was passed by a vote of 1,039 to 401.

Jan 4, 1916

A regular general meeting of the Canadian Mining Institute will be held in Vancouver, B. C., on Nov. 26-28. The Council extends a cordial invitation to all members of the American Institute of Mining and Metallurgical Engineers to attend.

Jan 11, 1919

CARACAS PETROLEUM Established February 24, 1957 Official year begins in January Harry J Sykes, Chairman G J Clarke, Vice-Chairman Robert S Longwell, Vice-Chairman David L Stepanek, Treasurer Robert C Newman, Secretary Texas Petroleum Co Apartado 267 Caracas, Venezuela

Jan 1, 1960

EDWARD B. GRUBB, Burlington, N. J.: In connection with the discussion relative to the effect of vibration upon the molecular structure of wrought-iron, I would like to call your attention to the following extracts from a work by William

Jan 1, 1897

By F. H. Spedding

CONSIDERABLE confusion exists in the literature concerning the phase transformations exhibited by the lighter rare earth metals; namely, lanthanum,1-8 cerium,1,3,5,8,9-15 praseodymium,8 and neodymium.1,8,16,10 To obtain further information

Jan 1, 1958

By Charles A. Ashburner

THE appliances which have been proposed, and the modifications in the construction of boiler-furnaces which have been made for the prevention of smoke, and the utilization of what are ordinarily called the waste products of combustion, have been innumerable.

Jan 1, 1882

By E. H. Crabtree

Research on the iron ranges begins to bear fruit in big plant construction -Big coppers raise capacity, build at new Arizona, Michigan, Nevada, properties - Hydrometallurgy comes to fore with new uranium ore treatment and the Chemico process for nonferrous metals -

Jan 2, 1953

By Oscar Glaeser

THE purpose of this paper is to present specific applications of the fundamental principles of mine ventilation and the means that are at our disposal to accomplish the task of maintaining a healthful atmosphere in small mines and prospect openings.

Jan 1, 1936

By S. Arthur Krom

(New York Meeting, February, 1912.) THE James diagonal-plane slimer is specially adapted to handle the finest slimes, but it will also handle sands as coarse as 40-mesh. The saving efficiency of this machine is due to the original construction of the deck, and to the rapid reciprocating movement imparted to it by the head-motion. The deck consists of a plurality of connected planes, having a certain fixed ratio of inclination one to another. These planes intersect each other diagonally to the stroke-line of the table and are arranged so as to give the pulp on the table a double treatment. This double concentration performed by the diagonal-plane deck produces cleaner concentrates and tailings than those obtained by the operation of two separate machines. The action of the diagonal planes settles, combines, and holds all the concentrates in one compact mass, sharply defined from the gangue, and easily cut away without loss. Many slime-concentrating machines distribute the feed-pulp for a distance of 4 or 5 ft. only, and upon a very limited settling-surface. This results in a thick, heavy deposit, from which it is impossible to stratify the values and wash, away the gangue, the resulting products being dirty concentrates, and tailings carrying high values. The diagonal-plane slimer distributes the feed-pulp for a distance of 10 ft., and upon a settling-surface having an area of 40 sq. ft.; in other words, it spreads the pulp thinly on the table, which allows the metallic values to settle through the gangue quickly, forming a bottom stratum from which the thinly-distributed overlying stratum. of gangue is easily brushed away by the feed-water without disturbing the underlying concentrates. Referring to Fig. 1, plane A is the main settling-section, of the table. The feed pulp flows gently down this plane and is

Jun 1, 1912

By Lester C. Uren

Petroleum occurs, in nature, as a fluid saturating the pore spaces between the grains of porous rocks or aggregations of rock particles such as sand, sandstone, conglomerate, shale, limestone, etc. The oil, under the influence of gas pressure, hydrostatic pressure, gravity, earth pressure, and, perhaps, other natural forces, is caused to flow through the porous "reservoir rock1' into wells penetrating the stratum in which the oil occurs. The principal moving force is the pressure of dissolved or occluded natural gas within the oil, though this force is assisted by gravity and by the hydrostatic or buoyant pressure of ground water about the edges of the "pool." The wells, providing outlets to the surface, are centers of reduced pressure and the flow of rock fluids into a particular well is usually an expression of the difference in pressure existing between the space within the well and that of the stored oil within the reservoir rock. The greater this differential pressure, the more rapidly will oil flow from the source rock into the well. Opposing movement of the oil from the reservoir rock into the well are certain natural forces related to the rock structure, such as pore friction and capillarity, and certain others related to the physical properties of the oil, such as viscosity and adhesion. The differential pressure between the well and the boundaries of the area drained by it must be sufficient to overcome the forces opposing flow if there is to be movement of oil into the well. If by any device the resistance to movement of the oil may be reduced, the oil will flow into the well at a more rapid rate and the effective area of drainage will be increased.

Jan 1, 1925

For convenience, we tabulate below the weight systems contained in the Probierbüchlein: [Pound and centner weights used by merchants for ore, lead, and copper I frother = 20 or 50 centners (depending on locality) I centner (Stolberg & Eisleben) = 112 pounds. I centner (Nuremberg) =100 pounds I pound =2 marks =32 lot =128 quintlein-512 pennyweights =1024 beller I mark -16 lot -.64 quintlein =256 pennyweights = 512 beller 1 lot= 4 quintlein= 16 pennyweights= 32 beller I quintlein = 4 pennyweights= 8 beller I pennyweight = 2 beller Netherlands mintmasters' weights for silver I mark =12 pennyweights=288 grains I pennyweight - 24 grains Assay weights for gold I mark= 24 carats 96 carat-grains. I carat = 4 carat-grains] The assayer's weights were miniature copies of the legal weights of his locality, intended, like the modern assay ton, to eliminate calculation. Each assayer made his own, not usually bothering about a given proportion between the true weights and the assay set, but maintaining the correct ratio between all the weights in any one set. The weights were quite small, to permit the use of less sample, but the exact size is nowhere stated in the Probierbüchlein. Even the legal pound varied considerably from place to place, depending on locality, and assayers would use different factors depending on the sensitivity of their balances, among other things. Agricola makes the assay centner equal to one actual drachma, by which term he means the German quintlein, or 1/12,800 of the full weight of the 100-pound centner. Schreittmann says that the 100-pound centner on the assay scale should be less than half a quintlein, i.e., the factor should be at least 25,600. Biringuccio says the assay centner might

Jan 1, 1949