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By S. A. Falconer

D. A. Dahlstrom—Mr. Falconer has done an admirable job of proving the adaptability of the cyclone to the beneficiation of a very difficult size range in the preparation of coal. The addition of the cyclone to other coarser size methods makes it economically feasible for the coal operator to rigorously control his marketed products at a high and uniform quality level down to the 48 and 100-mesh size. Furthermore, it should be pointed out that by utilizing the cyclone as a deslimer or classifier the —3 200-mesh fraction, usually containing large percentages of undesirable material, can also be quickly and cheaply removed from the clean coal. Advantages of such a step are several: (1) Reduction of ash content, especially where clays and slimes are serious. (2) lower moisture content of the final coal. (3) easier mechanical and thermal de-watering of the fine coal due to higher cake and bed permeabilities. The author has indicated that adjustable control means should be installed on the cyclone operating on a heavy-media slurry. This also holds true for the cyclone acting as classifier, deslimer or preliminary dewatering agent and is worthy of special emphasis. Such controls, while not necessarily automatic, must be simple, rapidly adjustable, and require a minimum of attention. Three methods available to the operator are (1) throttling valve on the feed line, (2) back pressure valve on the overflow, and (3) adjustable diameter underflow nozzles. The first two, while fulfilling the specifications, suffer the disadvantage of restricting capacity if severe throttling is necessary. The third method has little effect on capacity and easily maintains an underflow of correct moisture content. Several designs are possible, but two find the widest application. The first was developed by Robert Piros of The Truax-Traer Coal Co. and uses a simple casting containing two holders for underflow nozzles which can be rotated about an axis parallel to the cyclone centerline. These holders retain the underflow nozzle flush with the conical section walls. When a change in nozzle diameter is required, the new size is placed in the spare holder and rotated into place. A second design utilizes a soft rubber cylindrical tube which is compressed or released from three sides, causing the inner diameter of the tube to decrease or increase. This is achieved by using a machine-threaded,

Jan 1, 1951

By Walter Miller

NOW, after a year's continued impact of war, the task of the petroleum-refining industry stands out clearly and looms up in larger aspect. This time it is not, as it was so largely in the first World War, simply a matter of increased quantity- more and more of the same petroleum products that had substantially been standard for years. In this era the emphasis is largely on newer and improved materials which had been produced, if at all, in comparatively insignificant quantities, and for which manufacturing equipment was not available on a large scale. At the beginning of 1942 four great product needs (besides a number of lesser one-) confronted the industry: 100-octane aviation gasoline, toluene for T.N.T. production, high-quality lubricating oils for aviation and Army equipment service, and petroleum chemicals for synthetic rubber manufacture.

Jan 1, 1943

By Norman D. Fitzgerald

IN 1943 the petroleum industry completed a series of practical adjustments to the acute problems which dominated the scene a year earlier. The crisis in petroleum transportation from the Gulf Coast to the East Coast was met by the completion of overland pipe lines supplementing emergency haulage by tank car so pressure on consumers along the Atlantic Seaboard was appreciably relieved. Later in the year when the western Atlantic was largely cleared of submarines, the sharp reduction in the hazards of marine transportation permitted the resumption of coastwise traffic and imports from South America. Nationwide restrictions in the use of gasoline and fuel oils became necessary as military demands for all petroleum products mounted to high levels.

Jan 1, 1944

By H. D. Wilde

GREAT emphasis is being placed today on petroleum as a source of chemicals. Such prominence is well merited, for rapid strides have been made in developing processes for the conversion of petroleum into synthetic chemical products, which are now being made on a huge scale. These marvelous accomplishments have resulted in some highly optimistic predictions as to what can be expected in the future. Many of these forecasts are well justified, but some writers, especially those contributing to the Sunday supplements and the popular-cience type of publications, have let their imagination run wild and present a rather distorted picture of the possibilities in this field in the postwar period. Commercial manufacture of synthetic organic chemicals had its beginning in England with the establishment of a plant by Sir William Perkin in 1857 for the manufacture of "Aniline Purple" or "Mauve." The preceding year he had discovered in the laboratory how this dyestuff could be made from aniline, one of the many derivatives of coal tar, and he soon made commercial application of his discovery. Influenced largely by his success, organic chemists began research on production of a vast array of synthetic dyestuffs, medicinals, flavors, scents, and explosives. Rapid progress was made and by the turn of the century hundreds of these products were being manufactured. Most of these synthetic chemicals were derived from materials obtained as by-products in the conversion of coal into coke. These by-products are generally referred to as "aromatics" and are obtained by processing coal tar recovered in the coking process, so they are popularly known as "coal-tar chemicals." During the early years of this century, coal-tar chemistry was the wonder of the age, and rightfully so, since the products so made seemed limitless.

Jan 1, 1944

By D. A. Elgillani, M. C. Fuerstenau

With either sulfonate or oleate as collector, quartz responds to flotation with moderate additions of calcium only at moderately high pH, where some portion of the activator has hydrolyzed to caOH+ . Calculations of the concentrations of various ionic and precipitated species of calcium and collectors suggest that the products of [(CaOH+) (RSO3)] and [(CaOH+)(01-)] determine whether flotation is obtained under specific conditions. Ion products on the order of 10-12 were calculated for both the sulfonate and oleate systems. The activating effect of calcium ion in nonmetallic flotation systems is of considerable interest because of the normal presence of calcium in natural water. As a result, this phenomenon has received quite some attention in the past. Kraeber and Boppel1 showed that quartz could be activated by calcium above pH 10 with sulfonate as collector. The feasibility of selectively separating quartz from hematite with calcium activation at relatively high pH was demonstrated by Clemmer, Clemmons, Rampacek, Williams, and stacy.2 Cooke and Digre3 showed with a bubble pick-up method that the minimum quantity of calcium ion required as activator for complete pick-up of particles occurs at pH 11.5 for an addition of 20 mg per liter sodium oleate. They also showed that larger additions of calcium (10-fold increase per unit decrease of pH) must be added for complete bubble pick-up as the pH is reduced. Schuhmann and Prakash,4 using a vacuum flotation technique, found that quartz could be floated with moderate additions of calcium chloride and oleic acid at neutral pH, providing the metal ion was present in stoichiometric excess over the quantity needed to form the normal soap with oleic acid. They also reported that calcium will function as an activator only in basic media. More recently, Eigeles and volova5 have shown that essentially complete flotation of quartz is obtained with 6 x 10-4 mole per liter calcium chloride and 1.7 x 10-5 mole per liter sodium oleate at pH 11.6. while no flotation is obtained at about pH 10.9 and below. The importance of adsorption of activator and collector at the air-liquid interface is also demonstrated in these systems. The important role that metal ion hydrolysis assumes in quartz activation systems was also demonstrated recently.6-8 A detailed investigation of metal activation in sulfonate flotation of quartz was undertaken in one system7 and yielded a number of interesting and important observations. Quantification of the data of this system7 to the extent desired was not possible, though, because certain species could neither be ignored nor accounted for accurately. These difficulties can be circumvented when calcium is involved as activator. This detailed analysis was undertaken to obtain a more quantitative explanation of calcium and metal ion activation in quartz flotation. EXPERIMENTAL MATERIALS AND METHODS Sodium alkyl aryl sulfonate9 mol wt 450, and pure potassium oleate were used as collectors. All other reagents used were reagent grade in quality, i.e., n-amyl alcohol as frother, KOH for pH adjustment, and calcium chloride. Conductivity water, made by passing distilled water through an ion exchange column, was used in the investigation. Quartz was prepared by leaching the sized sample (48 x 150 mesh) with HC1 until no iron could be detected in the leach liquor. The experimental equipment and procedure were the same as that described previously.6,10 EXPERIMENTAL RESULTS As the presence of precipitates was noted in all of the systems to which ca++ and collector were added, experiments were undertaken to determine the solubility products of calcium sulfonate and calcium oleate using a nephelometer. With this technique, collector is titrated into a known solution, which in this case was 5 x 10-5 mole per liter CaCl2 at pH 5.5. Upon precipitation of the calcium-col lector salt, e.g., calcium oleate, light is scattered and detected

Jan 1, 1967

The Candelaria deposit was first discovered by Spanish prospectors in 1863; but its silver ore was not exploited on a large scale until 1873, when the Northern Belle mine was opened. The first Northern Belle mill was built at Belleville, 13 km (8 miles) to the northwest. From 1876 to 1886 the Northern Belle paid over $1 million in dividends each year. In 1882 a 43 km (27 miles) pipeline was built to Candelaria from the White Mountains to the west to furnish water for the mills and town at Candelaria; it was 100 mm (4 in.) in diameter, hand- riveted, and made in England. Sections of this pipe are used. as claim posts today. At its terminus at Metallic City, above Candelaria, a large concrete reservoir was built and called Metallic Lake. It is being used today by Candelaria Partners. Production at Candelaria declined after the mid-1980s, revived for a short period in the early 1890s, and during the 1920s a 300 ton mill operated for three years. Candelaria Partners is owned jointly by Occidental Minerals and Congdon and Carey, with Occidental being the operator. An engineering study done in mid-1979 resulted in engineering for the plant commencing in late that year and heap leaching being started in September 1980. Two million tons of ore per year containing 108 g Ag and 0.28 g Au per mt (3.15 oz Ag and 0.008 oz Au per st) will be mined from the Lucky Hill and Mount Diablo .areas about 1.6 km (1 mile) up Pickhandle gulch from the heap leaching operation. Waste -to -ore ratio is about 2:l. Ore is mined by front-end loaders and hauled by 85 ton trucks to the primary crusher, a 1,070 by 1,780 mm (42 by 70 in. ) gyratory. Primary crushed ore is conveyed to a stockpile of 10,000 tons live capacity from which it is reclaimed by hydraulic reciprocating feeders and conveyed to the crushing and agglomeration facility. This unit is composed of a 1.8 m by 2.6. m (6 ft by 12 ft) double deck screen, a 2.1 m (7 ft) standard cone crusher, and three conveyors. At the conveyor transfer points NaOH and NaCN solution is sprayed on the ore as it falls through a row of 75 mm (3 in.) hanging steel bars. During this process of turning and dividing the ore, the fines agglomerate with the coarse ore to give better percolation for the leach solution on the heaps. Provision was made for the later addition of 2 kg per mt (4 lb per st) of cement to aid in the agglomeration. Agglomerated ore at minus 50 mm (2 in.) size is then conveyed to a 390 mt (430 st) loadout bin where it is transferred to 85 ton rear dump trucks for haulage to the leach pads.

Jan 1, 1981

By H. E. Wheeler

THE work described was carried out during 1917 and 1918 at the testing laboratory of Watertown Arsenal at the instigation of the Nitrate Division and later with the concurrence of the Cannon Section of, the Ordnance Department, U. S. A. The experiments follow three principal lines of work: First, the effect of nitrogen under pressure on steel containers of various compositions at a red heat; second, the effect of decomposing ammonia on various alloy steels, iron, and non-ferrous alloys; third, a new theory of the erosion of guns in respect to the effect of nitrogen in steel. PART I In the Haber process for the manufacture of ammonia from its elements, it is necessary to have nitrogen and hydrogen of 1500 lb. per sq. in. (105.5 kg. per sq. cm.) at a temperature of 500 to 600° C. The steel containers for these gases gave trouble by failing without apparent cause. When the General Chemical Co. began to develop its method for the production of ammonia, it experienced the same difficulty and, knowing that the Haber process had solved the difficulty by the use of alloy steels, it made several small steel bottles of different compositions and kept them filled with these gases at this pressure and temperature until they failed. The time of service varied from a few days, for the plain steel casting, to two years for a chrome-vanadium forging. Four of these steel bottles were sent to this laboratory for investigation; they were a plain carbon-steel forging, a nickel-steel forging, a chrome-vanadium steel forging, and a chrome-steel forging. The time of service was as follows: plain carbon steel, 4 mo.; nickel steel, 6 mo.; chrome-vanadium steel, over 2 yr.; chrome steel, 4 mo. When these containers were cut open and the cross-section surface polished, they showed an inside zone with a different luster from the rest of the metal. Upon etching, this zone was almost unaffected while the rest of the steel etched normally.

Jan 4, 1920

By J. R. Dawson, A. B. Kinzel

THE purpose of testing is to determine whether the material in question is identical in all essential respects with similar material which has given satisfactory service. The most common method of securing such information is to select samples as representative of the entire material and subject them to destructive tests. As the welding industry grew, service data were accumulated and tests of welds took on new significance. New tests were devised and old tests modified so as to be more pertinent to welding. Moreover, in some cases the generally accepted procedure of testing by sampling is not accorded the same degree of confidence when applied to welds as in the usual applications. Thus, in instances where great hazard would be involved should the material fail, means of non-destructive testing have been sought with favorable results. Accordingly, tests used today may be divided into two groups, destructive and non-destructive tests.

Jan 1, 1930

By R. T. ROLFE

IN this critical age, people are not content .with the judgments passed on men and things long ago, but must needs revise them. It is an excellent spirit, so long as we do not start out with the idea that old opinions must necessarily be wrong, and that all ancient malefactors must therefore be whitewashed. That interesting ogre, Gilles de Retz, to whom the process has recently been applied, is no longer with us, so no one will be the worse for it, but the old bugbear8 of the steelmaker, sulfur and phosphorus, still are, and now Mr. McIntosh, in a recent article in these pages, asks us to regard one of them in a new light.' This article is a most interesting one, with much of which one must agree. One of his -statements, how- ever, although correct, is somewhat' misleading, and he rather discounts the fundamental objection of the steelmaker to phosphorus, its dangerous propensity to segregate and the secondary effect on the carbon distribution and therefore on the homogeneity of the steel that is produced thereby. Further, the evidence on which he bases his claim that phosphorus does not lower the impact strength of steel is rather slight. The writer views with the utmost misgiving any proposal to increase the amount of phosphorus in steel, and cannot regard it in any other light than as a prejudicial impurity, to be kept down to as low a proportion as possible. It thus becomes necessary to examine the evidence upon which Mr. McIntosh's claims are based

Jan 1, 1926

SAMUEL L. HOYT,* Minneapolis, Minn. -I was privileged to see the apparatus used by Mr. Scott, which is quite unique. It is, as the author says, a modification of the apparatus designed by Dr. Rosenhain, but it is evidently quite an; improvement. The author is to be congratulated on the fact that lie has given us, with his apparatus, a quantitative thermal analysis of these critical points. I notice the author refers to Ac3, Ac2, and Ac1. His designation of the Ac2 point is all right, but naturally in a steel with as much carbon as this, which would mean a hypereutectic steel, the other point might better be considered as an Ac, point with possibly another point above the Ac, point. Another important point brought out is the fact that, in Fig. 3, the lines representing the Ar1, transformation and the Ac,1_3 transformation do not intersect at the zero rate curve,

Jan 5, 1919

By Edward Keller

(New York meeting, February, 1912.) IN a paper, entitled A Uniform Method for the Assay of Copper Material for Gold and Silver,1 A. R. Ledoux invited the assayers of this country to contribute to a symposium, in which the results of their assays of given samples of copper-matte and metallic copper would be made comparable. This symposium 2 appeared about one year thereafter; and through it and its discussion, first became generally known the fact that the ,gold-yield by the all-fire method of assaying is usually higher than by the so-called combination (wet and dry) method, in which nitric acid is employed as a solvent for the copper. In the publication alluded to, the supposed cause of gold-losses in the latter method was declared to be the solvent action of copper nitrate, or of the reduction-products of the nitric acid, upon the gold. Up to a very recent date, gold has been held to be insoluble in pure nitric acid. (The solvent action of any chlorine present in the nitric acid must here properly be disregarded as belonging in the realm of carelessness. Among later allusions to this topic, W. R. Tan Liew 3 ascribes the solution of the gold in the combination-assay entirely to the action of nitrous acid at the high reaction-temperature of copper and nitric acid ; F. B. Flinn 4 a believes the low result in gold to be due exclusively to mechanical losses-finely-divided gold penetrating through the filter-paper-but presents no experimental data confirmative of this belief; and 0. Pufahl 5 attributes the solubility of the gold in some coppers to the presence of selenium-a view which appears to be shared by many as- 1 Trans., xxiv., 575 (1894). 2 Trans., xxv., 250 (1895). 3 Engineering and Mining Journal, vol. lxix., No. 16, p. 469 (Apr. 21, 1900). 4 Engineering and Mining Journal, vol. lxxxvii., No.11, p. 569 (Mar. 13, 1909). 5 Lunge, Chemische Technische Untersuchungs Methoden, vol. ii., p. 229 (1900).

Jul 1, 1912

By Saluja, Sunder S.

Man had to learn to break rocks as early as the Stone Age, when they formed his main source of raw material. He started with chipping and over the years has reached a stage where he can employ atomic blasts and break, with one blast, millions of tons of rock. In between these two extremes there have been several stages of development including fire setting, use of the expansion of water on freezing in chipped cracks in cold climates, the use of low or deflagrating explosive black powder in about the 17th century, the use of high explosives with the discovery of nitroglycerine in 1846 by Sobrero, followed by the monumental discoveries of the great Swedish scientist Alfred Nobel in the latter half of the nineteenth century.

Jan 1, 1968

By R. I. Jaffee, J. G. Dunleavy, W. Hodge, H. R. Ogden

Jan 1, 1949

By Paul T. Benson

MOST important of the various departments of a custom smelter, so far as the financial welfare of the plant and the confidence of shippers are concerned, is that responsible for correct weights, accurate moisture sampling, and the obtaining of control samples that are strictly representative of the lot of ore from which they come. Treatment rate schedules are based on the metal content of ores received, reduced to dry weight. These rates must be low enough to keep the ship- per from taking his business else- where and still must allow the smelter a profit. Assay results, likewise, must satisfy the shipper, but if they show too high a metal content for the ore they represent, the smelter will actually lose money. It is always considered, and constant checks through umpire assays prove, that laboratory results are closely correct, so the bur- den of the plant profit and loss and the satisfaction of the shipper rest squarely upon the sampling department.

Jan 1, 1936

By Clyde E. Williams

MUCH has been said recently concerning the depletion of the Lake Superior iron ore re- serves. Estimates given indicate a total life of the present known reserves of twenty to thirty years. Some argue that there is no need to concern ourselves about the possible depletion of the Lake Superior iron ore supply because foreign ores can be brought in to this country at a lower price than rich agglomerated ore can be produced from the lean domestic ores. Some fear, as a result of this, a displacement of the steel business from present districts to the Atlantic seaboard. Others show that foreign ores will be brought to interior points via the projected Great Lakes-St. Lawrence waterway. Others believe that the South, given better freight rates, will extend its iron and steel market into northern territory.

Jan 1, 1931

[Aase, Qlenn D., (Junior Member '40) Jr. Met.. American Smelt. & Refin. Co., Selby. Calif. Abadie, Henry G., (Junior Member '43) Petr. Engr.. Avenal, Calif. Abbott, Clarence E., (Member '04) Civil En=.. V.P.. Tennessee Coal. Iron & R.R. Co., 1542 Brown biarx Bldg.. Birminpham, Aln. Abbott. Fred E., Jr., (Member '44) Petr. Engr., C/O Arabian Anierican Oil Co.. A.P.O. 816. c/o Postmaster, New York, N. Y. Abel, Raymond L., (Member '28) Chem. Engr.. C. O., Pittsburgh Chem. Warfare Procurenlent Dist.. American Bank Bldg., Pittsburph. Pa. Abel, Walter D., (Member '32) Min. Engr.. Supvr. Engr.. RFC, Los Angeles, Calif.]

Jan 1, 1946

By Charles S. Barrett

THERE is a road into the microscopic realm that has remained untraveled through all these years of intense activity with high-power optical and electron microscopy. The road is worthy of careful scouting by metallurgists and other investigators, for it leads into relatively new country and it makes some areas accessible that heretofore could be reached only by very indirect paths or by the use of imagination. And when the road passes through familiar territory it frequently permits a new view of commonplace things that should prove of value from time to time. An accepted way to interest people in new sights such as this is to present an illustrated travelogue. This I propose to do, using many pictures taken in my recent exploration of this road. In the manner of travelogues, I shall touch briefly upon a large number of different subjects in physical metallurgy and shall, attempt to give an exhaustive treatment of none, for the objective is to provide a means for further research, to interest others in it, and to indicate what appears at the moment to be profitable directions for it to take. The method I shall present involves X-rays, but does not make use of the usual accompaniments of X-ray research such as reciprocal lattices, Fourier series, or the stereographic projection. The method is so simple in its fundamentals that it could have been developed 20 years ago, or perhaps even 30 years ago. It is well to have a destination for our travels, so that when we are through we shall have explored some region of importance, despite our preoccupation with the novel means of transportation and our interest in the sights to be seen along the way. So let us name the Cold Worked State as our destination, and make side trips into the territories known as Recovery, Recrystallization, and Precipitation-hardening. A great many investigations have been made of the nature of cold-worked metal, and a great variety of methods used, many of which are indirect, such as X-ray line intensities, X-ray line widths, calorimetric measurements, and magnetic measurements. Since comprehensive reviews of these investigations have been published in recent years, they need not be discussed here. The investigations that were the direct forerunners of the present work should be first mentioned. In 1931 I became interested in the structure of individual spots in X-ray diffraction patterns.1 When a crystal is placed in the narrow pencil of X-rays in a Laue camera, the spots recorded on the film are not always uniformly black, but may have an internal structure. The meaning of this may be understood from Fig. 1, which represents a narrow beam containing X-rays of many wave lengths ("general radiation") penetrating a crystal in the direction of the arrow and forming a pattern on the vertical film at the right.

Jan 1, 1945

By D. B. RUSHJIORE

(New York -Meeting, February, 1912.) TORCHES were used by the early Romans for mine-lighting, and these were followed by open lamps or earthen jars filled with tallow or oil, and later by candles. In early coal-mining, explosive gases seldom occurred, and, if they were encountered, the danger of explosion was materially diminished by the absence of any ventilating-system and the consequent insufficient circulation of air to form with the methane an explosive mixture. As the art advanced, the danger of fire-damp became more apparent, and methods for testing the air were resorted to as early as in the fifteenth century. The method of testing consisted in lowering a clog in a, basket down the shaft. As soon as he encountered fire-damp he would commence to howl, after which he was withdrawn, and a leafy bush was fastened to the end of the rope and run rapidly up and clown the shaft. This so disturbed the accumulation of gas as to cause it to rise out of the shaft. Later this odd method of testing was improved upon through the discovery that a light inserted in a body of fire-dam p would produce a blue flame. Candles were used for this purpose, and, when fire-damp was thus discovered, brushing or some other primitive method of fanning was resorted to for driving out the gas. In some instances the gas was burned away, regardless of the danger thereby incurred. A man, wearing a well-moistened coat and a mask with glass spectacles, descended in the mine a few hours before each shift. With a long stick, to which was fastened a burning torch or candle, lie would crawl on the floor with the stick so raised that the light would sweep the roof and ignite the gas which it encountered. In this position the flame of the explosion would pass over him, after which he would retreat from the gases resulting from the combustion. The occurrence of serious accidents resulted in

Jul 1, 1912

By WALTER CARROLL

Between cross currents of economic factors and international expediencies the iron and steel industry in 1948 made an outstanding contribution to the general economic picture. Were it not for an unfortunate episode during the month of April involving a temporary shortage of coal, 1948 would have been an all-time record year in output. Exceeded in no previous peacetime year, the production of iron and steel in 1948 totaled some 88,500,000 tons. That it was a worthwhile effort of no small magnitude is evidenced by the fact that in three and one half years following the war, this nation has produced as much steel as in the five years preceding the war. This figure of 88,500,000 tons is 68 per cent greater than that for 1939.

Jan 1, 1949

By Joseph B. Umpleby

PROGRESS in the petroleum industry in 1929 has been characterized by outstanding accomplishments in the fields of new discovery of supply, economic control of production, increased efficiency and reduced costs of recovery, and lowered costs and greater flexibility in manufacture. Resources have been developed in an outstanding degree in the Kettleman Hills. California, the Oklahoma City field (which adds a large potential area in central Oklahoma), the discovery of Woodbine sand production in East Texas, and the discovery of Wilcox sand production in west-central Kansas. Engineering technique has progressed both along the lines of development and production, with a net result that costs have been reduced and extraction increased in notable degree, although it is impossible to give a close measure of either. In the field of re- fining crude oils variations to the end of promoting reduced cost and greater flexibility has been more important than genera! acceptance of innovations in practice.

Jan 1, 1930