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United Engineering Trustees, Inc. ARTHUR S. DWIGHT GEORGE D BARRON J V. N DORR Engineering Societies Library Board ROBERT PEELE PHILIP W. HENRY GEORGE C STONE JOSEPH E. POGUE The Engineering Foundation H C BELLINGER GALEN H CLEVENGER J V N DORR

Jan 1, 1923

Jan 1, 1944

By John J. Strohl, Henry J. Schwellenbach

This paper relates the results obtained by decreasing the size of feed to a rod mill screen circuit. As would be expected, added production was gained and a finer grind with no tonnage loss was made possible.

Jan 12, 1950

Jan 1, 1969

Jan 1, 1933

Jan 1, 1944

Jan 1, 1902

United Engineering Trustees, Inc Engineering Foundation Engineering Societies Research Board Other Committees United Engineering Trustees, Inc. ARTHUR S. DWIGHT GEORGE D. BARRON J. V. N. DOER Engineering Societies Library Board ROBERT PEELS PHILIP W. HENRY GEORGE C. STONE JOSEPH E. POGUE The Engineering Foundation H. C. BELLINGER GALEN H. CLEVENGER J. V. N. DORR

Jan 1, 1929

By ALEX. S. THOMAS

HOWEVER good a furnace may be in regard to design, etc., or however excellent in the quality of the gas used, a suitable heat for the successful working of the metal cannot be obtained unless the melt be coated with a proper quantity of slag. This coating may be excessive or it may be deficient in quantity. The right degree of heat is the essential condition of successful working, for the quality of the steel made is never very good when the metal is allowed to simmer in the furnace for an excessive period, and this heat cannot be obtained if the metal is not protected by a proper covering of slag. This is not only to prevent the metal being over-oxidized and wasted, but also to prevent the metal being chilled when exposed with only a thin covering of slag. The slag may be obtained in either of two ways : 1, naturally, by the presence of sufficient silicon in the iron used, to unite with iron oxide to form a staple slag ; or, 2, by the addition of slag or free silica. In the first case the slag is formed naturally by the action of the oxygen in the flame - i.e., the oxidizing atmosphere of the furnace-on the silicon in the metal when melting. The charge then melts, as it is termed, "thick," and protects the banks from being cut. If too much silicon be present, however, and an excessive quantity of slag be formed, it will be found to be rather infusible, and unless care be taken to add the oxides quickly and follow the furnace up-thus rendering the slag more fusible by the extra iron oxide-the furnace bottom is liable to be pulled up. In such cases the author has frequently been able to warn

Nov 1, 1906

IRON AND STEEL COMMITTEE ALBERT SAUVEUR, Chairman. A. A. STEVENSON, Vice-Chairman. HERBERT M. BOYLSTON, Secretary, Abbot Bldg., Cambridge, Mass. John Birkinbine, William Kelly, J. S. Unger, William H. Blauvelt, Charles Kirchhoff, Felix A. Vogel, James Gayley, Richard Moldenke, Leonard Waldo, Henry D. Hibbard, Joseph W. Richards, William R. Walker, Henry M. Howe, C. F. W. Rys, William R. Webster, Robert W. Hunt, E. Gybbon Spilsbury, Frederick W. Wood. J. E. Johnson, Jr.,

Jan 1, 1914

By U. N. Bhrany, N. Arbiter

F. C. Bond (Consulting Engineer, Processing Machin-Dept., AllisChalmers Manufacturing Co., Milwaukee) This is a very comprehensive paper. It deals with 1) size distribution functions, 2) energy-particle size relationships, and 3) criteria for grinding efficiency. The method of analysis used consists of tracing the increase and decrease of successive Tyler scale screen fractions as grinding progresses. The treatment is based upon the assumption that the work done in grinding is concentrated entirely upon the coarse size fractions in the mill. It is postulated that when a feed consisting entirely of particles of one size fraction is batch ground that finer fractions increase at a constant rate as grinding progresses, until finally each in turn begins to be ground and to decrease in amount. It is shown that under these conditions the empirical Gates-Gaudin-Schuhmann log-log size distribution plot can be logically explained. It is difficult to imagine any condition of ball mill operation, or any probability analysis, which would result in no grinding contacts on the finer particles present. However, the authors' postulate must be accepted if their conclusions are to be sustained. They conclude that the equation expressing the for mation rate of each size fraction can be resolved into the G.-G.-S. size distribution equation, and that the curvilinear portion of the log-logsize distribution line represents the only particle sizes which are being ground as well as produced. The author's statement that the G.-G.-S. Eq. 4 applies only to the finer portion of the size distribution while the Rosin-Rammler Eq. 6 applies over the whole size distribution range certainly supports the view that an exponential equation of the Rosin-Rammler type corresponds more closely to actual size distribution than does the power law G.-G.-S. equation. However, the G.-G.-S. equation is used to derive Eq. 8 and Eq. 9, which state that the energy required to grind a ton through a particular mesh varies inversely as the particle size to the exponent -a , whic h is the slope of the extended G.-G.-S straight line. This is stated to apply to both batch and continuous grinding. The G.-G.-S. slope exponent thus becomes very important in all crushing and grinding analyses by this method. The authors include some data which can be used to test their conclusions, as described below: We will consider grinding a feed composed of 14 mesh (1190u) to -200 mesh (74u). The average of 17 Allis-Chalmers grindability tests on quartz gives a work index (Wi) of 12.77. The -200 mesh product should have 80 pct passing 41.6u or P = 41.6. The equivalent 80 pct passing size of the 14 mesh feed particles is considered to be the particle diameter, as is true for spherical particles. Thus F is 1190u. In the work index equation 10 wi 10 wi 127.7 127.7 P f 41.6 1190 = 16.1 kw-hrperton. In Table I the ball mill exponent for quartz is 1.0 and from Eqs. 9 and 10: w=kw-hr/ton =Constan/(do/di) = 16.1 ton so that (1190) Constant/ Constant and the Constant equals 259. The tons per horsepower-hour value is 0.0464, in agreement with Table IV. The exponents for other minerals are listed in Tabl e 11. In Table IIA, the kilowatt hours per ton required to grind these minerals between the same sizes as the quartz, both by the authors' method and the work index equation, are listed. According to the authors kw-hrperton = 259/(16.1)".

Jan 1, 1961

By Renato G. Bautista, Robert A. Hard

A comparative study has been made of the ex-tractability of several of the transitim metals from thiocyanate sohtions using methyl isobutyl ketone as the organic solvent. Extractions were made of scandium (III), chromium (III), manganese (II), iron (III), and cobalt (II), of which only the scandium , iron, and cobalt were readily extracted. All extractions were made at pH 2 and at 25.5 °C. A series of extraction experiments was made on scandium, iron, and cobalt to determine the effect of thiocyanate cmcentration added as the ammonium and also as the calcium salt. Also determined was the effect of metal ion concentratim and ionic strength on the distribution ratio. Analyses of the organic extracts indicated the scandium and iron were extracted principally in the uncharged trithiocyanate form, while the extractable form of the cobalt contained the cobaltotetrathiocyanate anion. THE chemical separation of metal complexes in solution by solvent extraction has in recent years been developed for large scale separation as well as bench scale work in the laboratory. It has also found increased application in analytical chemistry. Its extension to extractive metallurgy as a unit operation is best illustrated in the recovery of uranium and vanadium from their leached liquor.5-8 The extractability of some thiocyanate systems have been extensively investigated. The rate earths have been separated from one another using butanol as a olvent. Scandium was effectively extracted in ethyl ether using ammonium thiocyanate as the com-plexing agent.'' Similarly, the separation of hafnium from zirconium has been reported using ether""' or hexone13 as the organic solvent. The extractability of various metal thiocyanates in ethyl ether is given by 0ck.l Sharp and Wilkinson15 prepared nickel-free cobalt slats by thiocyanate extraction. The mechanism of extraction of titanium (IV) thiocyanate with methyl isobutyl ketone was determined by elafosse.''" The characterization of cobalt (TI) thiocyanate complex using methyl isobutyl ketone as the solvent at near neutral aqueous solution and the spectrometric studies of the ex-tractable cobalt complex has been made by Hard." It is noteworthy to mention at this point that the fundamental characteristic of ketone (oxonium) solvent extraction is that the extractable species are uncharged ion pairs solvated by the ketone molecules, but probably still partially hydrated.

Jan 1, 1963

By E. C. Pechin

AT the suggestion of some members of the Institute, attention is called to the record of the working of Dunbar Furnace during the twelve months ending in January, 1874. During this period, with a product of over eleven thousand gross tons, not a single ton of

Jan 1, 1874

By Barry N. Whittaker

INTRODUCTION Considerable progress has been achieved with long- wall mining in recent years especially in enabling increased rates and levels of output to be gained, higher standards of safety and increased usage of advanced technological developments. Longwall mining also has major long term advantages, prominent amongst which is general minimisation of the effects of pillars and room intersections giving rise to future instability problems as can be the case with room and pillar mining operations. The fact that longwall mining is not presently limited by depth below surface inclination of seams or thickness of seam to be worked strengthens its position as the most popular underground mining method for extracting coal seams in Europe. Its wider application in North America and Australia can give rise to significant economic benefits coupled with higher levels of safety and recovery of coal. This present paper reviews recent progress achieved and draws attention to the more important factors influencing longwall mine design and layout. LONGWALL STRATA PRESSURE ABUTMENTS A longwall gives rise to major redistribution of strata pressures. The roof behind a longwall is normally allowed to cave and permit subsidence of the overlying strata and eventually giving rise to a trough depression at the surface. Consequently, reestablishment of strata loading within the caved region behind the longwall depends upon effective caving and subsequent recompaction. This requires sufficient depth pressure and/or adequate width of extraction in relation to the depth to achieve breaking of overlying roof beds necessary to reload the extracted region. Figure 1 shows results of an analysis carried out by Whittaker and Singh (1979) indicating the pattern of redistribution of vertical stress around a longwall in the plane of the seam. The analysis represents the average depth of longwall working in the UK, and was performed using a stress balance assumption of compatibility before and after mining. The main stress abutments are indicated by (1) the front abutment strata pressure zone which travels with the longwall, and (2) the flank abutment strata pressure zone which

Jan 1, 1982

By Philip E. LaMoreaux

Fluoride, generally less than 0.5 ppm, is present in ground water from rocks of Paleozoic age and older, in northern and eastern Alabama. Some of the water-bearing formations in the Coastal Plain area of the State yield water with as much as 6.8 ppm fluoride.

Jan 8, 1950

By A. D. Taylor

In recent years there has been an increasing effort to attract students into engineering. Obviously, the effort is necessary because young people find the image of the engineer unattractive. Some of the things they find unattractive are real, some are not, and part of the problem is too little knowledge of the field. First, I would like to comment on some of the ideas which appear to be justified. Engineering is a difficult course of study. True, and nothing can or should be done to change this. The education is continually being improved, but it is unlikely to be made easier.

Jan 1, 1970

JOSEPH W. RICHARDS, Chairman. J. E. JOHNSON, JR., Vice-Chairman. ARTHUR S. CALLEN, Secretary, 453 Chestnut St., So. Bethlehem, Pa. SUB-COMMITTEES IRON ORE DWIGHT E. WOODBRIDGE, Chairman. ERNEST F. BURCHARD, WILLIAM KELLY, CHARLES F. RAND, FELIX A. VOGEL. BLAST FURNACES II. A. BRASSERT, Chairman. WILLIAM H. BLAUVELT, AMBROSE N. DIEHL, JAMES GAYLEY RICHARD V. McKAY. STEEL WORKS HENRY D. HIBBARD, Chairman. GUILLIAEM AERTSEN, C. F. W. RYS, .1. S. UNGER. FRANK D. CARNEY, A. A. STEVENSON, WILLIAM It. WALKER. MECHANICAL TREATMENT CHARLES A. BUCK, Chairman. ROBERT W. HUNT, GEORGE MESTA, FREDERICK W. WOOD.

Jan 6, 1915

By H. M. Chance

The Taviche district is about 12 miles from the town of Ocotlan in the State of Oaxaca, and about 250 miles south of the City of Mexico. Its altitude rises to something more than 5,000 ft.; and although within the tropics (latitude about 17° N.) the climate is mild and salubrious, neither excessively hot in summer nor cold in winter. The phrase, "perpetual spring," which has been applied to it, aptly describes the weather during my stay. Sugar-plantations, bananas and other tropical and semitropical fruits flourish in the valleys, while the hills

Jan 1, 1905

By G. G. Reed

G.G. Reed, Jr. The authors are to be commended for finding a material for pellets binding that we were unable to uncover during the investigations that led to US Patent No. 3,748,116, "Method for producing metallic iron powder from iron ore concentrate," July 24, 1973, by G.G. Reed, Jr., J.M. Karpinski, and S.V. Fox. This patent concerns a method of processing "super"-concentrates prepared from magnetite or "blue dust" into molding-grade metallic iron powder for use as a bulk commodity, in contrast to current methods which produce small batches that are custom-blended with additives and/or alloys to customer specifications. The one thing we had not found at that time was an organic binder (mineral-matter-free) that would allow induration to produce hardened pellets that would survive SL/RN Direct Reduction. Peridur appears to provide this missing link needed for large scale (200 t/a, or 220,460 stpy) single line plant capacity consistent with a low market price to ensure greatly broadened use of metallic iron powder. I hope that industry will adopt this combination so that metallic iron powder usage can fulfill its potential. ?

Jan 1, 1986

(The following list contains the names of those members of the Institute of whose connection with military service we have only recently become acquainted; it also includes the names of a few who have recently been promoted or transferred, indicated by a *. A complete list was published in the Year Book, issued as a supplement of the Bulletin for March, 1918.) ANDERSON, AMIL A., Co. A, 309th Regiment Engineers, 84th Div., American E. F., Care Postmaster, New York. ARMSTRONG, HAROLD K., Pilot, Naval Aviation, U. S. Naval Air Station, Miami, Fla. BASSETT, ARTHUR F., Co. 6, -E. 0. T. S., Camp Humphreys, Va. BEDDALL, THOMAS H., Adjutant, 1st Battalion, 1st Gas Regiment, American E. F. BERNARD, CLINTON P., Candidate, 12th Observation Battery, F. A. C. 0. T. S., Camp Taylor, Ky. BROOKE, LIONEL, 50th Co., 13th Battalion, 5th Replacement Engineers, Camp Gordon, Ga. BROWNING, EDWARD, Corp., 1st Regiment Engineers, Co. D, American E. F. BUGBEE, EDWARD E., S. A. T. C. Headquarters, Raleigh N. C. BUTTERFIELD, G. BRUCE, CO. C, 605th Engineers, American E. F. CADOT, J. J., 1st Lieut., U. S. Air Service, American E. F., Care Post- master, New York. CARLOCK, J. B., Major, 2d Battalion, 1st Gas Regiment, American E. F., France.

Jan 12, 1918