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By P. D. I. Honeyman, P. A. Faust

At the Miami plant of the International Smelting Co., Inspiration, Ariz., there are four reverberatory furnaces, all 120 ft. long. At present only one of these furnaces is in operation. It is operated as a wet-charge furnace, the charge being distributed for about 65 ft. down the furnace length. Usually this charge contains about 12 per cent moisture and runs 25 per cent sulfur, of which there is eliminated in the furnace from 25 to 30 per cent. The furnace is oil-fired, the fuel being burned in a battery of Cananea-type, low-pressure burners. The flame is kept short and conditions so adjusted as to obtain complete combustion within the furnace. The average furnace draft, taken through the verb arch, amounts to only 0.02 in. of H2O. Draft is purposely kept low to cut down infiltration through the flues and boiler settings, and control dampers are regulated to maintain this uniform condition throughout the charging as well as the smelting period. Hot gases discharge from the furnace uptake through a common header flue to the waste-heat boilers. The general layout and dimensions of the plant are shown in Fig. 1. Four Stirling boilers, two of class M-26 (713 hp.) and two class M-31 (850 hp.), serve the furnace. Three usually are sufficient to take care of normal operation, the fourth boiler being used as a spare when necessary. The distribution of hot gases to the various boilers is regulated by the dampers in the boiler exit flues. Normally the boilers closest to the furnace uptake would evaporate more water than do those farther away, but dampers are regulated so as to distribute fairly well the load between the several boilers. Steam from the waste-heat plant is delivered to the adjoining power house of the Inspiration company, where it is used both in the Nordberg blowing engines and for electrical generation. Steam pressures and temperatures recorded are those in the main power-plant header and are thus inclusive of all losses in about 500 ft. of 10-in. line. Steam for smelter heating and auxiliary use is taken from the main waste-heat header, is reduced to 125 lb. and distributed through separate lines. Boiler feed water is supplied by the power plant and consists of returned condensate, augmented to a large extent by make-up water

Jan 1, 1934

By R. M. Sellwood

The No. 4 I.S.F. Smelter Complex at the Avonmouth Works of Imperial Smelting Corporation (N.S.C.) Limited commenced operation at the beginning of 1968. The furnace rating is 120,000 tons zinc and 40,000 tons lead per annum. Zinc and lead concentrates are unloaded onto a 1,000 tons per hour capacity conveyor belt and automatically weighed and sampled before receipt into a 48,000 ton capacity raw material store. Distribution is by a reversible boom stacker into 16 x 3,000 ton bays and recovery is by a front end loader. Materials are fed to 16 proportioning bins for feeding via continuous weigh feeders to a 132 square metre effective updraught area sinter machine with a material flow rate of 240 tons per hour over the machine. The required quantity of output lump sinter at up to 800ºC is fed to 2 x 600 ton storage bins on the I.S.F. plant. By-product SO2 rich gas is fed to a conventional wet gas single stream acid plant rated at 600 tons per day utilizing a dry N.T.P. gas volume of 100,000 cubic metres per hour. The hot sinter and preheated coke (800ºC) are automatically neighed and charged to a 27.3m2 shaft area I.S.F. fitted with 2 x 5.5 m. wide lead splash condensers. Grade 4 zinc is tapped and transferred to the zinc refinery. Conventional type lead bullion and slag are tapped from the bottom of the furnace through a separation forehearth. The refinery consists of 6 lead and 3 cadmium columns to produce some 52,000 tons per annum of S.H.G. metal. S.H.G. metal and Grade 4 metal is cast into various shapes as required.

Jan 1, 1970

By Ralph W. Bailey, William B. Price

During the past three or four years, the fabricators of silicon-bronze alloys have endeavored to induce users of phosphor bronze to use instead the silicon-bronze alloys, claiming that the silicon bronzes are superior to the phosphor bronzes for switches and springs, or where high fatigue resistance is desired. This paper gives the results of tests comparing several phosphor bronzes with a 3 per cent silicon bronze and a copper-nickel-tin alloy (Adnic), all processed by the Scovill Manufacturing Co. So far as the authors are aware, sheet-metal fatigue tests have not been made on any of the alloys included in this report, except on one phosphor bronze, material C, Table 1, which was tested by Townsend and Greenall1. Endurance Limit The majority of fatigue tests are designed to determine the endurance limit of a material. The number of repetitions of stress that will serve to establish an endurance limit varies with different materials. For ferrous materials, H. F. Moore2 has shown that stresses that do not cause failure up to 10,000,000 stress cycles will not cause failure up to 100,000,000 (and sometimes to 1,000,000,000) cycles. Thus an endurance limit for ferrous materials can be determined with a minimum of 10,000,000 stress cycles. For nonferrous materials, no such generalization holds. R. R. Moore3 has shown that for manganese bronze and elektron metal, 13,000,000 and 28,000,000 cycles, respectively, will serve to determine an endurance limit, while certain duralumin specimens gave no indications of having reached an endurance limit up to 400,000,000 stress cycles. J. B. Johnson6 showed that an endurance limit for duralumin was not found by tests running up to 500,000,000 cycles. H. F. Moore2

Jan 1, 1937

By Woolsey McA. Johnson

In metallurgical circles it is known widely, but somewhat vaguely, that the ease of reduction of metallic oxides depends largely on the way they hare been prepared. It is likewise known that different forms of carbon have different and greatly varying reducing powers. It is the purpose of this paper to show somewhat more definitely and scientifically these facts. Some years ago the writer published an account of pyrometric determinations of the reduction temperature of zinc oxides variously prepared and of several kinds.' In said paper it was shown that the temperature at which zinc oxide evolves zinc according to the equa-tion ZnO + C = Zn + CO depends upon the nature of the two reacting bodies. The determina-tions had a range of accuracy of from 2° to 6°C., whereas differences were found to amount to an extreme of 90' C. So the differences are real ones and must have a definite cause. The equation of boiling water, (H2O)4 D 4 (H2O) has a fixed temperature for equilibrium of 100° C. at 760 mm. pressure. In general, all equations reacting in the liquid or the gaseous phase have well-defined constant physical conditions which govern the equilibrium point and reaction velocities. In a reaction where we have one or more solid phases, the tempera ture conditions requisite for the unbalancing of the stable system are found to vary. These variations are due to the fact that in a solid there is a very complex molecule and it is not a question solely of the tearing away of two interlocked atoms, but also of the destruction of a complex molecule containing hundreds, or possibly thousands, of smaller molecules. In other words, there are two forces to be overcome: a certain

Jan 1, 1914

By Fred Beasley

METALLURGISTS have, in the past ten years, overcome many difficulties of high zinc in lead blast-furnace slags. This problem was brought to the front at the close of the late war, by the price obtained for lead and the high cost of labor, fuel, and flux. The Port Pirie plant of the Broken Hill Associated Smelters, Australia, early in 1919 had increased the zinc oxide in its blast-furnace slags from 13.5 to 20 per cent., at the same time reducing the iron oxide in the slag from 33.5 to 25.6 per cent. These results were obtained by the following proceduret the addition of granulated slag to the roaster charge, 10 to 12 per cent., improved conditions of the crushing and mixing and roasting of the constituents of the sinter. By experiments and improve-ments the practice at this plant has developed a normal slag that carries 22 per cent. zinc oxide, and at times runs as high as 33 per cent. zinc oxide, with only slight furnace trouble. The granulated slag is used not, only as a diluent to the sulfur in the roaster charge, but also on account of its value as a slag-forming material and on account of the physical properties it imparts to the finished sinter. The ore is mixed with flux and given a double roast. All the first roasting is by sintering with the Dwight & Lloyd machines. The final roasting is performed partly by Dwight & Lloyd machines and partly by H. & H. pots. The charge to the blast furnaces consists chiefly of the final sinter, slag shells, siliceous and non-bearing sulfur, lead ores. High blast and ore columns are the practice. The greatest care is taken to obtain in the final sinter as low a sulfur content as possible.

Jan 2, 1925

By MCA Woolsey

(Butte. Meeting, August, 1913.). IN metallurgical circles it is known widely, but somewhat vaguely, that the ease of: reduction of metallic oxides depends largely on the way they have been prepared. It is likewise known that different forms of carbon have different and greatly varying reducing powers. It is the purpose of this paper to show somewhat more definitely and scientifically these facts. Some years ago the writer published an account of pyrometric determinations of the reduction- temperature of zinc oxides variously prepared and of several kinds.1 In said paper it was shown that the temperature it which zinc oxide evolves zinc according to the equation Zn0. +' C = Zn + CO depends upon the ;nature of:., the.' two reacting bodies. The determinations bad a range of accuracy of from 2° to. 6° C.,whereas differences were found to. amount to an extreme. of 90° C. :.86 the differences are real ones and must have, definite cause. The equation of boiling water, (H20)4 = 4 (H2O) has a fixed temperature for equilibrium of 100° C. at 760 mm. pressure. , In general, all equations. reacting e in .the liquid or the gaseous phase have-well-defined constant physical conditions which govern the equilibrium point and reaction velocities. In a reaction where we have one or more solid phases, the temperature conditions requisite for the unbalancing of the stable system are found to vary. These variations are due to the fact that in a solid there is a very complex molecule and it is not, a question solely of the tearing away of two interlocked atoms, but also of the destruction of a complex molecule containing hundreds, or possibly thousands, of smaller molecules.

Jan 7, 1913

E. A. Peretti (University of Notre Dame, Notre Dame, Ind.)—Mr. Deitz and Professor Halpern are to be congratulated on a fine piece of work which adds to our knowledge of precious metal—cyanide-solution reactions. I should like to offer the following comments: The authors state, "the rate plots were always linear, indicating a zero order reaction rate." This appears to conflict with the data of Fig. 6 which clearly show the rate to vary with the NaCN concentration. It seems to me that the rate curves are linear because of the experimental setup. The volume of solution is so large that over a three-hour period the change in NaCN concentration is very small. A rough calculation for the experiments of Table I where the initial NaCN strength was 0.0096 mol per liter show a change of NaCN concentration of about 0.0009 mol per liter at the end of three hours. In short, over the period of time that the experiment was in progress, the NaCN strength was practically constant; hence the rate of dissolution remained practically constant. Eq. 10, as written, specifies that 1 mol of H202 and 2 mol of hydroxyl ion are formed when 2 mol of silver react. Is this true? The effect of H,O2 on the rate was made in solutions having an oxygen pressure of 4.8 atm. Were any tests made in solutions containing hydrogen peroxide, but no oxygen? G. M. Willis (University of Melbourne, Melbourne, Australia)—The authors have shown that, under their experimental conditions of high O2 concentrations, the rate of solution of silver in aqueous cyanide solutions is controlled by diffusion of O2 or CN- to the metal surface. With diffusion control, it is generally not possible to obtain further information about the mechanism of a process.

Jan 1, 1955

By John Chipman, Raymond L. Orr

Recently reported high -temperatlnre thermal data have been incorporated in a reuieu' of the therinody-r~ar,zic propesties of iron. The recent data permit mot corlsisterlt and reliuble choices to be made for many of the pvoperties, resnlling in bettev eslablished tabrtlations of the thermodynamic functions. Values of Cp, h°t- - H°298. s°t - S2sa, and (G°T -H298/T are tabulated for -the solid and liquid phases of iron in both stable and melastable regions. Consistency of the tabulations has been maintained to the precision necessr~vg to yield the Gibbs energy change belween the bcc (a, 8) and fcc (y) phases of iron at temperatures pertinenl to alloy studies. THE importance of the metal iron has stimulated many investigations of its thermodynamic properties at elevated temperatures. Reviews and summaries of the data have appeared from time to time. Among these the 1951 paper of Darken and smith' deserves highest recognition for the quality of its criticism and for the precision and thermodynamic consistency of its tabulations. These and the more recent table of Kaufman, Clougherty, and weiss2 reproduce the Gibbs energy of the (a, 6)--Y transformation with sufficient sensitivity for alloy studies. Other recent compilations of equal validity3-' make no attempt to do this. Since this Gibbs energy change is not greater than 22 cal per g-atom over the temperature range 1100° to 1800°K, it is obviously desirable to tabulate values of (G°t - H298)/T to four places of decimals even though the absolute accuracy would not warrant such precision. The necessity for reconsideration of the problem is emphasized by the recent publication of several important researches on the enthalpy and heat capacity of iron. The older work is well-covered in the reviews cited and will be mentioned here only when actually employed in the tabulations. GAMMA IRON Transition temperatures are taken from the selec -tions of Elliott and Gleiser,5 based on the work of Boulanger7 and earlier workers. For the a-y (A3) transition at 1184°K we retain the value 215 cal per g-atom adopted by Darken and smith.' It has received confirmation in the recent work of Dench and Kubaschewski,' and of Braun8 using adiabatic calori-metry, and of Wallace, Sidles, and Danielson10 using a pulse heating technique. The enthalpy data of Olette and ferrier" and of Anderson and Hultgren12 at higher and lower temperatures may be extended to 1184°K to give the following values which are adjusted to the required value of ? 1184 Ha,1184 Ha 298 = 8030 cal per g-atom [11 hr,1184-ha298 = 8245 cal per g-atom [2]

Jan 1, 1968

The Colorado Scientific Society, Denver, Colo Charles Henderson, President, 519 U. S Custom House, Denver, Colo. Beginning in 1882, up to. about 1919, the Society published 11 volumes containing many valuable papers From the informa¬tion at hand, the papers in those volumes are now only available in libraries or on file at institutions. Vols 12 and 13 are the current volumes, and the list of the geologic papers contained in them are given here For any information as to price and availa¬bility, address the above. Vol 12 (1929-31) No 1, The geology of the Sangre de Cristo Mountains, by J H Johnson, 2, Relation of the ore deposits of the southern Rocky Mountain region to the Colorado Plateau, by B S Butler; 3, Mosquito Range and the Leadville district, by C H Behre, Jr , 4, Geologic history of the Front Range, by T S Lovering, 6, Revision of geologic structure and stratigraphy in the Ouray district, by W S Burbank, 7, Localization of ore in the schists and gneisses of the Mineral Belt of the Front Range, by T. S. Lovering, 8, Relation of the ore deposits of the southern Rocky Mountain region to the Colorado Plateau, by J. B. Tenney; 9, Preliminary geologic map of the Alma mining district, by Q D. Singewald and B S Butler, 10, The Climax molybdenum deposits of Colorado, by B S Butler and J W. Vanderwilt, 12, Localization of ore bodies at Rico and Red Mountain, by G. F Collins, and Geology of Mount Lincoln and Russia mines, by Q D Singewald and B S. Butler. Vol 13 (1932- ): No. 1, Preliminary geologic notes on Galena Mountain, by J. W Vanderwilt, and High plains of Colorado and New Mexico (Late Tertiary history), by F. M. Van Yuyl and J M. Coke

Jan 1, 1933

By H. H. Stout

IN the early fall of 1025, the writer was conducting, in the Ledoux and Co. labora-tory, New York, experiments directed to-ward ascertaining the effect on its impurity content when cathode copper was subjected to a current of various gases at an elevated temperature below the melting point. The apparatus consisted of a vertical I-in. dia. silica tube about 12 in. long, heated on the outside. The cathodes were broken to pass 3/8-in. mesh, and a current of various differ-ent gases was passed up through a 4-in. long column of these loose cathode particles in the vertical tube furnace. Temperature was maintained to 1500° to 1600°F. and the gas treatments lasted from 3 to 6 hr. The writer observed that whenever reducing gas (H2 or CO) was used, these cathode par-ticles stuck together at points of contact with each other. The cohesion was so marked and tenacious that an examination was made of the fractured surfaces, when cathode particles were broken from the cluster. Crystal growth was always found to have taken place across the surfaces where separate particles were in contact, but only after all oxides, sulphates, etc., had been completely removed. The idea of a possible new process was then conceived and was disclosed to A. M. Smoot (V. P. Ledoux and Co.) with intent to obtain his views. The first conception as given Smoot was "to gas-clean broken cathodes, put them in an extrusion press, solidify and extrude them at around 1500°F." Smoot's reaction, after a few moments considera-tion, was, "It looks perfectly all right to me." The writer and his assistants, W. H. Osborn and H. H. Stout, Jr., after confer-ring as to ways and means, decided to go ahead with preliminary laboratory experi-ments, which, it was thought, would move the new process from the possible to the probable. This program followed a course indicated by three basic considerations: I. Since brittle cathodes were often unin-tentionally produced, it seemed probable that the laws controlling this type of deposi-tion could be ascertained. 2. We had already proved the gas-clean-ing feature. 3. There remained to prove: whether a sound, homogeneous metal billet could be produced with crystal growth established over the entire surface of each individual particle in the billet; and, if so, what would be the physical properties? Osborn arranged with Columbia Uni-versity for conducting experiments in its research laboratory to prove or disprove the third item; Columbia assigned C. A. Phillipi, Jr. to assist in the project. A press with a cylinder 2 in. high and of I-in. dia. was used. It was surrounded and heated by a resistance coil of Nichrome wire. Broken tough cathodes were used.

Jan 1, 1940

By Basil B. Zavoico

PRODUCTION of crude it in the United States during 1939 totaled about 1.255,776,000 barrels, an average of 3,440,482 barrels per day, 3.41 per cent above the 1938 output of 1,214,355,000 barrels but 1.83 per cent below the record pro¬duction of 1,279,160,000 barrels, in 1937. However only the two-week shutdown of oil fields in the Southwestern States in August and September prevented the domestic crude production from establishing an all-time record in 1939. Demand for all petroleum products for the first ten months of 1939 showed an increase of 7.04 per cent over the similar period of 1938. Domestic demand for all petroleum products was particularly benefited by the increasing industrial activity, advancing 8.37 per cent above the like period of the preceding year equivalent to a volume increment of 256,810 barrels per day; with motor-fuel demand gaining 5.83 per cent and demand for all fuel oils gaining 12.15 per cent over the corresponding period of 1938. The export demand for the first ten months of 1939 was slightly below the export movements during the same period of 1938, declining 0.56 per cent. The European war was a major factor in 1939 for the petroleum industry in the United States, even if, at the end of the year, the war had not yet resulted in the expected large shipments to England and France.

Jan 1, 1940

By Frank A. Hill

A visitor to the Northern anthracite coal-field in 1844 wrote: " History and song have hallowed the valley of Wyoming, and everything pertaining to it seems wrapped in an atmosphere of romance." Song and history have since been almost forgotten in the rush of enterprise and business energy, while the invested capital which has built 160 colliery plants, producing last year 17,031,826 tons of coal and giving employment to 50,000 men and boys, lends an atmosphere the inspiration of which is the very sustenance of prosperity and progress. The fundamental cause of this great valley's financial strength, however, rests on the fulness of its mineral wealth. Its mountains surround and its cities are built upon anthracite coal. Its foundation, physically, financially and socially, is coal. Its geology has governed its growth and developed its greatness. In 1768, ten years, prior to the celebrated Wyoming massacre, two Connecticut Yankees, named Gore, settled near Wilkesbarre, Luzerne County, and, burning Pennsylvania anthracite in their blacksmith's forges, were the first to utilize it as a fuel. Its first use in the household was also at Wilkesbarre, where, in 1808, Judge Fell burned it in an open grate. Carbondale, Wilkesbarre, and Scranton were early recognized as the coal centers of the field.

Jan 1, 1887

LIST OF REFERENCES COMPILED BY ENGINEERING SOCIETIES LIBRARY FUEL POSSIBILITIES IN STEEL MAKING. Iron Age, November 6, 1913, p. 1056-1059. Paper read before the American Iron and Steel Institute, by William Whigham. The author discusses the use of pulverized coal as a fuel for open-hearth furnaces. IMPROVED PULVERIZED FUEL FEED DEVICE. Iron Age, November 6, 1913, p. 1024. Brief description of the Dunn apparatus, especially intended for cement kilns, but used also in the nodulizing of iron ore. WIDER UTILIZATION OF PULVERIZED COAL, H. R. Barnhurst. Iron Age, October 23, 1913, p. 906-908. Part of discussion of paper by James Lord on The Use of Pulverized Fuel in Metallurgical Furnaces, read before the Engineers' Society of Western Pennsylvania. POWDERED COAL FOR OPEN HEARTH FURNACES. Iron Age, October 16, 1913, p. 855. Abstract from the "Coal and Coke Operator." USE OF PULVERIZED COAL AS A FUEL FOR BOILERS, R. C. Carpenter. Sibley Journal of Engineering, December 1913, p. 85. COAL-DUST FIRED BOILER. Indian Engineering, November 29, 1913, p. 301. PROGRESS IN FUEL UTILIZATION. Mining and Scientific Press, October 25, 1913, p. 638. BUFFALO GRAIN-ELEVATOR DUST EXPLOSION. Engineering News, July 31, 1913, p. 223-24. Reprinted in the National Fire Protection Association Quarterly, October, 1913, p. 149-151. Mention is made of the danger of explosions in connection with the burning of powdered coal. POWDERED FUEL AND EXPLOSIONS. Railway Age Gazette, July 18, 1913, p. 53-84. Letter by W. D. Wood. USE OF PULVERIZED COAL IN METALLURGICAL FURNACES, James Lord. Engineers' Society of Western Pennsylvania, Proc., October, 1913, p. 363-371; discussion, p. 371-417. With bibliography.

Jan 3, 1914

Jan 1, 1893

By RAYMOND M. LARSEN

The area covered by this paper is the same as that covered in 1944. Colorado, Montana, Utah, and Wyoming are included in the discussion and statistics, and brief mention is made of activities in the adjoining states, except Nebraska and New Mexico, which are considered separately (see pp. 187-189). The other adjoining states, North and South Dakota, Arizona, Nevada, and Idaho, have had virtually no oil or gas production, except in the gas field of Cedar Creek. Montana, which extends into North Dakota; the Pierre field in South Dakota, where gas is produced and separated in gas-water wells, and the abandoned Payette area in western Idaho. Seven gas wells were drilled in North Dakota, but no wildcatting was reported. Several unsuccessful wildcats were drilled in South Dakota, and some were continuing at the end of the year. Activity in Idaho and Nevada was negligible.

Jan 1, 1946

By J. T. Burwell

The crystal orientation in silicon iron that has been given a particular treatment described by Goss,l has been studied by Goss, by Bozorth2 and by Sixtus,3 but their results do not agree and are almost entirely qualitative. The following pages give a description of the orientation of the crystals in the material as determined by means of X-rays and expressed graphically in a pole figure. The treatment consists of hot-rolling the material into strip and then giving it two cycles of cold reduction followed by recrystallization. This produces remarkably good properties in the rolling direction, the product having a maximum permeability in this direction of more than 25,000 and a permeability at 16,000 Gauss of more than 2200. It is now generally agreed that Goss's original conclusion1 that the crystals in the final product are randomly oriented was incorrect, since Bozorth2 and Sixtus,3 using different methods, have shown that there is a decided preference in orientation. Those writers, however, expressed their results only in terms of one or more ideal orientations with deviations therefrom. X-ray Data A strip of the material containing 3.1 per cent Si, prepared by Goss,† 1.2 by 0.0125 in., was etched rapidly in warm dilute hydrochloric acid until it was 0.005 in. thick, in order to eliminate the effect of the two surface layers. The specimen was then mounted in an integrating camera similar to one described in the literature.4 The purpose of this camera is to translate the specimen during exposure, so that a statistically large number of grains contribute to the pattern photographed. The camera also allows the plane of the specimen to make various angles with the X-ray beam. An area 5 by 1.2 in. was scanned by a beam of unfiltered radiation from a molybdenum target tube operating at 37 kv., and the measurements were made principally on the peak of the white radiation. X-ray photographs were taken at intervals of 15" in a plane

Jan 1, 1940

By J. T. Burwell

The crystal orientation in silicon iron that has been given a particular treatment described by Goss,l has been studied by Goss, by Bozorth2 and by Sixtus,3 but their results do not agree and are almost entirely qualitative. The following pages give a description of the orientation of the crystals in the material as determined by means of X-rays and expressed graphically in a pole figure. The treatment consists of hot-rolling the material into strip and then giving it two cycles of cold reduction followed by recrystallization. This produces remarkably good properties in the rolling direction, the product having a maximum permeability in this direction of more than 25,000 and a permeability at 16,000 Gauss of more than 2200. It is now generally agreed that Goss's original conclusion1 that the crystals in the final product are randomly oriented was incorrect, since Bozorth2 and Sixtus,3 using different methods, have shown that there is a decided preference in orientation. Those writers, however, expressed their results only in terms of one or more ideal orientations with deviations therefrom. X-ray Data A strip of the material containing 3.1 per cent Si, prepared by Goss,† 1.2 by 0.0125 in., was etched rapidly in warm dilute hydrochloric acid until it was 0.005 in. thick, in order to eliminate the effect of the two surface layers. The specimen was then mounted in an integrating camera similar to one described in the literature.4 The purpose of this camera is to translate the specimen during exposure, so that a statistically large number of grains contribute to the pattern photographed. The camera also allows the plane of the specimen to make various angles with the X-ray beam. An area 5 by 1.2 in. was scanned by a beam of unfiltered radiation from a molybdenum target tube operating at 37 kv., and the measurements were made principally on the peak of the white radiation. X-ray photographs were taken at intervals of 15" in a plane

Jan 1, 1940

Discussion of the paper Of JAMES JOHNSTON, presented at the New York meeting, February, 1914, and printed in Bulletin No. 85, January, 1914, pp. 107 to 133. CHAIRMAN E. GIBBON SPILSBURY.-I would like to call attention to the fact shown in this paper that less than five years or perhaps seven years ago nobody had thought it possible to cyanide with success silver ores. The cyaniding of silver and gold ores was first of all started in Mexico, and gradually extended to this country in the case of the silver ores alone. The average extraction, I think, for the metals in Mexico, in the case of the silver ore, is less than 85 per cent., whereas here, in the case of a very complex ore, carrying a high percentage of sulphur and arsenic, and other objectionable elements, the ore has been treated so as to extract an average of 95 per cent. of the silver contents of the ore. It is really a phenomenal revolution in the metallurgy of silver ores which has been demonstrated and worked out at the Nipissing mines. GEORGE A. PACKARD, Boston, Mass.-I would like to suggest a slight modification, perhaps, of the statement which is made that no one considered cyaniding of silver ores up to five, or perhaps seven years ago, because in 1897, when I was at Mercur, Utah, one mill near there was operating on silver ores. It did not operate very successfully from a commercial standpoint, because they did not have a great deal of ore, but the extraction, I was told, was very satisfactory, and I am quite confident that it was, because, as suggested by the name, Chloride Point, the ores were silver chloride ores, and of course very easily soluble. Some years before that, in 1892, I made some tests myself. I spent three months making tests on more or less complex silver sulphide ores at Virginia City, Mont., and while our tests on the plain sulphide ores, finely ground, were quite successful, on account of the presence of a small amount of copper we did not work out a satisfactory solution of the problem at that time; although since then a cyanide plant has been erected and for at least eight years these ores have been treated by cyaniding at Virginia City, and the mill is still in operation. The period of five to seven years should, therefore, be modified considerably, in justice to the pioneers in the cyanide processes. REGINALD E. HORE, Toronto, Ont., Canada.-I hoped that there would be metallurgists from Cobalt here to present and discuss Mr. Johnston's paper. In their absence a few remarks from me may help to make clearer to you what they have accomplished.

Jan 6, 1914

US 4,132,635 -In the froth flotation beneficiation of low- grade siliceous iron oxide ore, an aqueous pulp of undeslimed ore is conditioned first with a reagent formed by incorporating a water-soluble polyvalent metal salt into an aqueous solution of sodium silicate and then with oleic acid or other anionic collector and optionally pine 011 or other frother. The conditioned pulp is subjected to flotation to concentrate Iron oxide values in the froth D. C. Yang, assigned to Michigan Technological University Jan 2, 1979 7 pp (209-1 66) Filed 1-1 3-77 (759,094) Drawing below.) [ ] US 4,133,038-In the froth flotation beneficiation of copper sulfide ore or other ores, an aqueous suspension of a mineral sample of uniform grain size and composition is conditioned with a strongly adsorbable collector in an amount which is a fraction of the amount sufficient to create a monomolecular layer on the mineral grains, and the conditioning continued until the entire amount of collector is adsorbed The conditioned pulp is subjected to flotation, the floated particles separated at timed intervals, and the flotation rate coefficient determined. By varying the degree of adsorption in repeated treatments, the dependence of the flotation rate coefficient on the degree of adsorption may be determined A Nieml Jan 2, 1979 10 pp (364-502) Filed 12-7-77 (858,353) Priority Finland, 5-26-75 (75/1,525) Same: British 1,533,723, dated Nov 29, 1978 Same Canadian 1,065,066, dated Oct 23, 1979 US 4,133,746System and method for maintaining substantially steady state conditions in the froth flotation beneficiation of copper ore, molybdenum ore, or other metal ores The mass flow of flotation concentrate from the cell is monitored continuously, and the rate of admission of aeration air into the pulp in the cell is varied inversely with respect to variations in the mass flow control of rougher flotation cells is accomplished with a single valve G W Dopson, assigned to Magma Copper Co Jan 9, 1979 6 pp (209-1) Filed 11- 23-76 (744,306

Jan 1, 1980