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The Institute is custodian of funds for support of numerous gold medals and prizes and has representatives on boards awarding still others. Details regarding the Institute Awards are given below. The Institute is represented on the boards of the John Fritz Medal, the Hoover Medal and the Washington Award, in connection with the three national societies of Civil, Mechanical and Electrical engineering; and, also, in the case of the Washington Award, with the Western Society of Engineers. Robert W. Hunt Medal and Prize THE partners of Robert W. Hunt established a fund which was presented to the Institute at a fitting ceremony on May 27, 1920, to establish an annual medal and a sum of money to be awarded under the following rules: 1. The award shall consist of two prizes: first of a gold medal, second of a sum of money; a certificate to accompany each prize. The money prize shall not be awarded to a member over 40 years of age, but under unusual circumstances, both prizes may be allotted to one person provided that he is not over 40 years of age. In general it will be understood that the Committee shall award the money prize to the younger men, rather than the medal. 2. The awards shall be made not oftener than once a year to that person or persons contributing to the Institute the best original paper or papers on iron and steel. The scope of the term "iron and steel" shall be determined by the subcommittee considering the awards. In general, papers dealing with the practical side of the subject have preference over those dealing with the theoretical side in recognition of the fact that Captain Hunt's main contributions to the industry have been in the improvement of production and quality of material. 3. A subcommittee of three to five, including the Chairman of the Iron and Steel Division, shall be appointed by the Iron and Steel Division annually to adjudge the award subject to approval. 4. The awarding committee shall submit its report to the Iron and Steel Committee at its October meeting, and the award shall be certified to the Secretary of the Institute in time to permit the presentation to be made at the Annual Meeting of .the Institute. 5. The recipient of the award shall be designated "The Hunt Medalist." Awards of the medal have been made as follows: 1920—-Robert Woolston Hunt. 192G—John A. Mathews. 1926—Charles Lewis Kinney, Jr. 1929—Edgar Collins Bain. 193G—James Aston. Awards of the prize have been made as follows: 1928—C. H. Herty, Jr. 1929—William E. Griffiths.

Jan 1, 1930

By John S. Brown

As a part of a symposium on the relations of structure to ore deposition, in February 1938, the writer presented some tentative opinions derived from his experience with a number of important lead-zinc replacement deposits. These ideas were set forth, as a basis for discussion and a stimulus to further inquiry, in a mimeographed leaflet that read as follows Intimate acquaintance with a number of lead and zinc deposits in metamorphosed limestones seems to indicate the existence of certain common features from which can be established some general principles governing the localization of ore in this type of formation. It is suspected that these principles can be applied, with modifications, to mineralization in unmetamorphosed limestone. In metamorphosed formations, some observed rules are as follows: 1. Bands or masses of pure limestone are very resistant to replacement by ore solutions, and are likely either to contain no ore or to resist replacement until near the end of mineralization. The reason for this apparently is physical, not chemical, since microscopic data indicate that when ore is deposited by far the greater part of it substitutes for carbonate. The chief factor is believed to be a lack of porosity in massive limestone that has undergone flowage and recrystallization. 2. Masses of intensely siliceous or silicated rock are likewise unfavorable ore receptacles. This seems to be accounted for by two factors: (a) chemical unsuitability or resistance to replacement, and (b) physical resistance to small-scale brecciation, which might facilitate the opening of effective channelways for solutions. Some low-grade ore may occur, however, and also sporadic fracture fillings. 3. The optimum condition for ore reception appears to be found in bands or areas containing carbonate and silicates (or quartz) intimately mingled in something like equal proportions. In this situation movement is likely to result in mixed flowage and fracture, producing a fine-textured porosity that admits solutions freely and provides access to an abundance of replaceable carbonate. Cleavage cracks in some minerals such as diopside are believed to facilitate the penetration of solutions. 4. Certain minerals or assemblages are regarded as favorable impurities in a limestone and others as unfavorable. Original quartz, and subsequently developed diopside, and perhaps garnet, are typical favorable pre-ore gangue; in general rather equidimensional, brittle minerals. Tremolite, biotite, and probably wollastonite, are typical unfavorable pre-ore gangue; in general highly elongated and somewhat flexible minerals likely to develop under strong shearing stresses. 5. Tentative opinion is that the ratio of lime and magnesia in a limestone is of little or no importance.

Jan 1, 1940

By A. U. Seybolt

RECENTLY, cases of coexisting ordered and disordered phase equilibria have been reported among face-centered cubic metals,1"3 but not on body-centered cubic systems.4 McQueen and Kuczynski5 showed a single line as the boundary between ordered solid solution of Fe3Al type and corresponding disordered solution in the Fe-A1 phase diagram based mainly on dilatometric and magnetic measurements. Such a single line would indicate a second or higher order transition. or an absence of coexisting order and disorder. The writer found previously a two-phase equilibrium region at 800°C consisting of ordered and disordered solid solutions of Fe3Si in a matrix of approximately 1-6 wt pct Si (Fe3Si is of 14.3 wt pct Si). A similar two-phase region of ordered and disordered Fe3Al solid solutions might be expected if the similarity between Fe3Si and Fe3Si structures hold true. In the present investigation, a wire of 22 at. pct Al, balance Fe and 0.0513 cm in diameter was subjected to electrical resistivity measurement in vacuum as a function of temperature between 300 and 800°C, see Fig. 1. There was excellent agreement between data taken on heating and on cooling: no hysteresis was observed. The Curie temperature was determined to be 640 °C which agrees with the finding by McQueen and Kuczynski.5 But in addition, there were two transitional points in the resistance-temperature plot at 510oC and 400 "C. The former is thought to be a connection with the transition from disordered state to a coexisting order and disordered equilibrium state; while the latter, from such coexisting state to ordered state. Fig. 2 shows a phase diagram where the suggested two-phase region lies between dotted lines. The solid lines are those of McQueen and Kuczynski.5 Since these authors found only a single-phase boundary between ordered and disordered Fe3 Al, it would seem likely that the dilatometric method used by these authors was not sufficiently sensitive to resolve the ordering reaction into the two-phase boundaries. In addition, their phase diagram conflicts with the statement they make on P. 1 of their paper: "The sharpness of the peaks indicates that ordering to Fe3A1 is a first order reaction." The suggestion of coexisting order plus disorder in Fe3A1 must be considered tentative until confirmed by high-temperature X-ray examination. If

Jan 1, 1961

By William A. Mitchell

AN X-ray diffraction pattern for "calcined cold precipitated ferric oxide" is reproduced dia-grammatically along with data for other iron oxides by R. C. Mackenzie.1' This pattern, which shows spacings higher than those for any other form of iron oxide, was obtained from material prepared and photographed at several different times over a period of weeks, but later attempts to reproduce the results were unsuccessful, the pattern of hematite being obtained every time.2 In an attempt to solve this problem, the original photographs showing the strange diffraction pattern were examined and a marked similarity to the hematite pattern was noticed, suggesting that the pattern was in fact due to hematite but corresponded to a shorter wavelength of X-rays than the Cu Ka which was assumed to have .been used. The eight strongest lines were provisionally identified with the strongest hematite lines and, by means of the corresponding hematite spacings, the X-ray wavelength was calculated for each line. This gave an almost constant value, with the exception of the innermost line which was somewhat diffuse, and confirmed the presence of hematite. The value obtained, 0.703 ± 0.015Å, corresponds to the molybdenum Ka wavelength. The X-ray tube used was a four-filament demountable tube with a copper target. Other photographs, mostly of soil clays, taken during the same period gave normal patterns of Cu Ka radiation with one exception. This was a calcined soil clay with a high iron content and also showed Mo Ka lines of the hematite structure. The explanation is almost certainly that the copper target was contaminated with molybdenum, but it is not known how this occurred. Specimens of alumino-silicates gave their normal Cu Ka pattern, but as the K absorption edge of iron is a little longer than the Cu Ka wavelength, specimens with a high iron content greatly reduced the intensity of the Cu Ka diffraction lines relative to that of the lines due to the shorter Mo Ka wavelength. The formation of hematite on calcining cold precipitated hydrated ferric oxide3 is thus confirmed. References R. C. Mackenzie: Investigations on Cold-precipi-tated Hydrated Ferric Oxide and its Origin in Clays. Problems of Clay and Laterite Genesis, p. 69, Fig. 4, F. AIME Symposium, St. Louis, Mo. Feb. 19-22, 1951. Published 1952. 'R. C. Mackenzie: Ref. 1. Note added on proof. V. C. Hansen and L. T. Brownmiller: Equilibrium Studies on Alumina and Ferric Oxide and on Combinations of These with Magnesia and Calcium Oxide. American Journal of Science (1928) 5, No. 15, pp. 225-242.

Jan 1, 1954

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By Eugene F. Poncelet

This paper attempts to analyze the phenomena involved in the fracture of brittle solids by simple compression. Glass squares standing on edge, and compressed between two parallel steel jaws, developed jagged fractures, roughly parallel to the compression. Polarized light disclosed the presence of high local stress concentrations indicating poor contact all along the contact surfaces with the steel jaws. Teszar has shown that partial contact between the jaws and such a compressed solid causes tensile stresses in the free surfaces of the solid normal to the compression. Furthermore, Scoble has shown that in brittle solids fractures are caused by, and develop normally to, a sufficient tensile stress. It follows that such "partial-contact" cracks must be expected. With optically flat jaws and specimens, no "partial-contact" cracks developed. Instead, very smooth cracks vertical to the compression appeared 'upon release of the pressure. Investigation showed that the friction with the rigid steel opposed the return of the glass to its original width, after creeping on the steel as compression built up, thus setting up tensile stresses in the glass surfaces. It was not found possible to eliminate these "release" cracks. Compressed to destruction, such specimens flew to dust. A Microflash photograph taken during the explosive disintegration revealed: (I) oblique parallel fragmentation cracks, 30" off the direction of the compression; (2) transverse forking fragmentation cracks, normal to the former; (3) release cracks parallel to the compression; (4) a disintegration cloud. Given a distribution of submicroscopic cracks of random orientation throughout the glass, Griffith has shown the highest tensile stresses to be located at the tip of the cracks 30" off the direction of the compression. Although the preexistence of such cracks or flaws in unstressed glass is doubtful, they can be generated by the distorting forces set up by the compression itself. Atoms, in a structure held together by Morse-type forces or bonds, have under tension both a stable and an unstable state-of equilibrium. The difference in energy level between these two states is a function of the tension, and this difference must be borrowed from the thermal energy level of the bonds to reach the unstable state and result in a broken bond. As the fraction of the bonds having at any instant a sufficient thermal energy level is a known function of that level, it is possible to determine, in function of the prevailing tension, the fraction of the bonds that are broken. Upon breaking of the bond uniting two atoms at the tip of an advancing crack, the two atoms accelerate away from each other, causing in the solid propagation of a

Jan 1, 1944

By Howard I. Smith

THE mineral trona was discovered on Government land in 1938, about 18 miles west of the town of Green River, Wyo., in the core of the John Hay, Jr., well, a test well drilled for oil by the Mountain Fuel Supply Co. in sec. 2, T. 18 N., R. 11o W., sixth principal meridian. Although no oil or gas was reported, the drilling led to a discovery of great potential economic importance and exceptional scientific interest. Trona is a relatively rare mineral found at various places in playa deposits but not previously found at any great depth. It is composed of hydrous sodium carbonate and sodium bicarbonate (Na2CO3.NaHCO3.2H2O). Pure trona contains the equivalent of 70.35 per cent of sodium carbonate. Total sodium computed to carbonate times 1.42 equals the percentage of trona in the absence of other sodium carbonate minerals in the sample. ANALYSES Two short pieces of core sent to the author a few days after the completion of the Hay well were analyzed by R. C. Wells† and found to be exceptionally pure trona. A brief article on this discovery has already been published.1 Arrangements were then made through W. T. Nightengale‡ for the author to inspect and sample the core. The company log of the well included notations of sodium salt crystals from a depth of 1190 to 1820 ft. Not being able to identify all the minerals present, the author selected several specimens of the core for petrographic examinations and sampled the sections of trona for analysis. J. J. Fahey, of the Geological Survey, examined the specimens and reported most of the crystals to be a new anhydrous sodium carbonate and calcium carbonate mineral (Na2CO3.2CaCO3), which he named shortite,2 after Maxwell N. Short.* He analyzed the samples of trona, with the results shown in Table i. [ ] In addition to the 10 ft. I in. of trona in the first section, it is reasonable to assume that the 9 ft. 8 in. for which no core was available for sampling is either mostly trona or some other soluble salt, but it should not be included in calculating reserves. In the part of the core between 1590 ft. 3 in. and 1600 ft. 4 in. the material insoluble in cold water, amounting to about 5 per cent, was estimated petrographically to contain 70 per cent clay, 25 per cent shortite, and 5 per cent pyrite. ACCOMPANYING MINERALS Fahey later secured about 600 ft. of the core for a detailed examination and study

Jan 1, 1942

By Eugene F. Poncelet

This paper attempts to analyze the phenomena involved in the fracture of brittle solids by simple compression. Glass squares standing on edge, and compressed between two parallel steel jaws, developed jagged fractures, roughly parallel to the compression. Polarized light disclosed the presence of high local stress concentrations indicating poor contact all along the contact surfaces with the steel jaws. Teszar has shown that partial contact between the jaws and such a compressed solid causes tensile stresses in the free surfaces of the solid normal to the compression. Furthermore, Scoble has shown that in brittle solids fractures are caused by, and develop normally to, a sufficient tensile stress. It follows that such "partial-contact" cracks must be expected. With optically flat jaws and specimens, no "partial-contact" cracks developed. Instead, very smooth cracks vertical to the compression appeared 'upon release of the pressure. Investigation showed that the friction with the rigid steel opposed the return of the glass to its original width, after creeping on the steel as compression built up, thus setting up tensile stresses in the glass surfaces. It was not found possible to eliminate these "release" cracks. Compressed to destruction, such specimens flew to dust. A Microflash photograph taken during the explosive disintegration revealed: (I) oblique parallel fragmentation cracks, 30" off the direction of the compression; (2) transverse forking fragmentation cracks, normal to the former; (3) release cracks parallel to the compression; (4) a disintegration cloud. Given a distribution of submicroscopic cracks of random orientation throughout the glass, Griffith has shown the highest tensile stresses to be located at the tip of the cracks 30" off the direction of the compression. Although the preexistence of such cracks or flaws in unstressed glass is doubtful, they can be generated by the distorting forces set up by the compression itself. Atoms, in a structure held together by Morse-type forces or bonds, have under tension both a stable and an unstable state-of equilibrium. The difference in energy level between these two states is a function of the tension, and this difference must be borrowed from the thermal energy level of the bonds to reach the unstable state and result in a broken bond. As the fraction of the bonds having at any instant a sufficient thermal energy level is a known function of that level, it is possible to determine, in function of the prevailing tension, the fraction of the bonds that are broken. Upon breaking of the bond uniting two atoms at the tip of an advancing crack, the two atoms accelerate away from each other, causing in the solid propagation of a

Jan 1, 1944

By Willard P. Ward

I DESIRE to put on record a fact in relation to the effect of manganese on pig iron which I have never seen in print, and which may, perhaps, not have been observed by anyone except myself. In 1875, while experimenting on the production of ferromanganese in a blast furnace, I had burdened the furnace with a charge which I calculated would produce a 15-per cent spiegel. The furnace was very hot, having been running for a couple of days on a very light burden, and making a burnt iron, preparatory to the experiment I proposed to make to produce a high grade of spiegel. I calculated that the charge would begin to work in the furnace in about twelve hours after it was put on. After the lapse of that time I commenced to watch the furnace carefully, but found little or no. change in the appearance of the metal, although there was a very decided change in the cinder, showing that the manganese ore had come in work. The iron was quite gray and very tough. The character of the cinder was good for a spiegel cinder, and I could not imagine where the manganese was going to, as it (lid not appear to be in either metal or cinder in anything like the quantity indicated by the charge. The next morning things were still in, the same condition. The furnace was very hot, the cinder good, and the iron very gray. I was then sorely puzzled. I had never heard of a gray iron with over 4 or 5 per cent, of manganese, and had no notion that an iron with more manganese could be gray and tough. With great difficulty a piece for chemical test was broken from a pig. Not less than a hundred blows from a heavy sledge were required to break it off I took the specimen to the shop and directed that some borings from it should be brought to the laboratory, as soon as possible, whither I myself at once repaired -to put things in readiness for a rapid manganese determination. In about half an hour the machinist came in with the iron specimen in one hand and about, a dozen blunted and broken steel drills in the other, saying that it was impossible to drill the iron. There were several little depressions in the iron, which was malleable enough to be indented by the point of the drill, but not a chip had been cut from it. The metal was never subjected to further physical tests. A chip broken from

Jan 1, 1882

By E. J. Rapperport, J. P. Pemsler

We have made calculations to evaluate the sensitivity of atomic absorption as a technique to measure vapor pressure changes with temperature. Our conclusion, supported by the experimental findings presented in this work, is that the ultimate sensitivity of the technique is well below lo-' Torr. This magnitude of vapor pressure sensitivity makes the method extremely attractive for thermodynamic studies. Atomic absorption techniques have been used previously in this connection by Scatchard and Boyd' and by vidale2 with a much lower sensitivity reported. Scatchard and Boyd's work measured cadmium pressure over Ag-Cd alloys in the range 0.02 to 0.3 Torr, and Vidale estimated that sensitivities of only 10"5 to 10"6 Torr are to be expected. Atomic absorption appears to be particularly well-suited to thermodynamic studies for several reasons: A) It is extremely sensitive; our experiments indicate an ability to measure vapor pressure changes of 10"9 Torr. B) It is highly selective; there is seldom interference among the resonant wavelengths of the various species. C) It may be performed in an absorption cell under static conditions. This alleviates such problems as surface impoverishment of alloys, attainment of equilibrium, and temperature measurement and control. D) Simultaneous, or near-simultaneous, vapor pressure measurements may be made for several elements in a given system. Experimental. The physical basis of the technique is the highly selective absorption of particular wavelengths by specific atomic species. In most atomic absorption work the element of interest is incorporated into a hollow cathode lamp to provide a characteristic spectral source of high intensity. The spectra lines characteristic of the element in the cathode are attenuated by atoms of that element in the radiation path. Radiation from silver or cadmium hollow cathode lamps was directed along a path containing a 10-cm evacuated silica cell. The cell was positioned within a silica windowed furnace and contained silver, cadmium, or an Ag-Cd alloy. As the furnace temperature was elevated, the number of atoms of the absorbing element in the vapor phase within the cell rose, and the resonant radiation was increasingly absorbed. Intensities were measured by passing the radiation through a Techtron Model AA-4 one-half meter grating atomic absorption spectrometer equipped with a photo-multiplier detector. In order to minimize instabilities in the source, the hollow cathodes were allowed to warm up for several hours and were run at only 2 5 to 30 pct of their maximum rated amperage. In addition the attenuated beam was monitored before and after each reading. The attenuation of resonant wavelengths may be related to vapor pressure by the following relationships.

Jan 1, 1969

By W. P. Ward

I desire ho put on record a fact in relation to the effect of man ganese on pig iron which I have never seen in print, and which may, perhaps, not have been observed by anyone except myself. In 1875, while experimenting on the production of ferroman ganese in a blast furnace, I had burdened the furnace with a charge which I calculated would produce a 15-per cent. spiegel. The fur nace was very hot, having been running for a couple of days on a very light burden, and making a burnt iron, preparatory to the experiment I proposed to make to produce a high grade of spiegel. I calculated that the charge would begin to work in the fur nace in about twelve hoars after it was put on. After the -lapse of that time I commenced to watch the furnace carefully, but found little or no change in the appearance of the metal, although there was a very decided change in the cinder, showing that the man ganese ore had come in work. The iron was quite gray and very tough. The character of the cinder was good for a spiegel cinder, and 1 could not imagine where the manganese was going to, as it (lid not appear to be in either metal or cinder in anything like the quan tity indicated by the charge. The next morning things were still in the same condition. The furnace was very hot, the cinder good, and the iron very gray. I was then sorely puzzled. I had never heard of a gray iron with over 4 or 6 per cent. of manganese, and had no notion that an iron with more manganese could be gray and tough. With great difficulty a piece for chemical test was broken from a pig. Not less than a hundred blows from a heavy sledge were required to break it off, I took the specimen to the shop and directed that some borings from it should be brought to the laboratory, as soon as possible, whither I myself at once repaired to put things in readi ness for a rapid manganese determination. In about half an hour the machinist came in with the iron specimen in one hand and about a dozen blunted and broken steel drills in the other, saying that it mas impossible to drill the iron. There were several little depressions in the iron, which was malleable enough to be indented by the point of the drill, but not a chip had been cut from it. The metal was never subjected to further physical tests. A chip broken from

Jan 1, 1882

By Henry N. Toler

Development in the Jackson gas field, Hinds and Rankin counties, for 1935 continued at a slow pace, there being only nine wells drilled on the structure, of which five resulted in gas producers and four in dry holes. There were no wells drilled deep enough during 1935 to test any of the horizons below the producing Selma chalk. There are 113 producing gas wells in the Jackson gas field, with three wells on the southeast edge of the field making some oil with a large quantity of salt water; this oil comes from the same horizon as the gas. The combined open flow of the 113 gas wells is about 4,100,000,000 cu. ft. The proven area of the field is approximately 8000 acres. The production of 10,291,000,000 cu. ft. for 1935 represents the largest yearly pull from the field by almost a billion cubic feet. The total production from the field to date is 45,104,000,-000 cu. ft. It is interesting to note that the rock pressure has dropped from 1010 lb. per sq. in. initial to 943 Ib. at the end of 1935, a decline of only 67 lb. in 6 years. There is a difference of opinion as to the age of the deepest formation tested on the Jackson structure; some people holding that it is Tuscaloosa, others, Trinity, and still others that it is Paleozoic, probably Pottsville. The production of the Amory gas field, Monroe County, continued to decline and the capacity was far under the demand. Originally there were four producing wells in the field with a combined open-flow capacity of approximately 15,000,000 cu. ft. and a rock pressure of 680 lb. per sq. in. At the end of 1935 only two wells were producing with a combined open-flow of less than 1 million cu. ft. and the rock pressure down to 100 lb. or less. No attempt has been made to drill new wells in the immediate field but three wells are being drilled in the county in an effort to secure new supplies of gas. The wildcat operations for 1935, with only 11 wells drilled, were the lowest since 1932, just about one-half the number drilled during 1934. None of the wildcat wells drilled in 1935 resulted in producers and, so far as the writer is aware, did not uncover any large structures. The 11 wells drilled were abandoned or junked at comparatively shallow depths, except the well drilled in George County to 6928 ft. by the United Gas

Jan 1, 1936

By James Norman, O. C. Ralston, John Dasher

MOST mineral products are used in the finely divided state, but some are sold in larger sizes. Coal, gravel, metallurgical fluorspar, phosphate rock, hematite, chromite, and other products are sold in sizes coarser than can be treated by many mineral-dressing methods. Gravity separation of coarser sizes by log washing and jigging is probably as ancient as any process now in use. The performance of jigs on a feed with sufficient difference in density of the minerals is excellent, but many families of minerals are too similar in density to be separated effectively by this method. The use of heavy suspensions of fine solids to separate coarse coal from bone and slate has been in use for some years. This separation by sink-and-float was limited until recently to light minerals. Development of galena and ferrosilicon as suspension media, by Minerals Beneficiation, Inc., at Mascot, Tenn., Pitcher, Okla., and Crosby, Minn., under patents granted during and since 1938, has permitted excellent results to be obtained on minerals of very similar densities up to 3.3. This process has been put in the hands of American Cyanamid Co. for exploitation, and further research now in progress may increase the density of suspension obtainable so that separation, at a density of 4,0 may be practicable before this is published. The Huntington-Heberlein dense-medium process, developed in England, is also being commercialized in the United States by Sink and Float Corporation. Du Pont has developed a sink-and-float separation using halogenated hydrocarbons as parting liquids; at this writing, the method is used commercially only on coal but has been successful in the pilot plant on many other minerals using tetrabromethane at densities up to 2.95. While these processes were being developed to extend the range of separation by difference in density to the coarser sizes, the Bureau of Mines was engaged in developing a process that will extend the range of separation by difference in wettability up to 2-in, size. War work has pushed aside its further development indefinitely. The results are published here with the hope that some use may be suggested that will justify post-war development, and so that readers that may be able to make immediate use of the scheme may have the information. EARLIER WORK It has been known since the time of Herodotus (B.C. 484(?)-425) that water-repellent particles will adhere to sticky surfaces. That early historian reports the

Jan 1, 1942

By Wilbert G. McBride

Two Also 3 1/2-ton motor trucks were used by Young Bros. while operating at the Mammoth Collins mine at Shultz, Ariz. One was equipped with an oil tank holding 1,075 gal. and was used for the transportation of "tops." The other was fitted with a stake body and used to carry machinery, wood, rails, pipe and all classes of miscellaneous supplies. The bodies were made of oak with maple flooring and were attached to the frame of the chassis by U-bolts, to avoid drilling the main members of the frame. Most of the hauling was done from Tucson, a distance of 47 1/2 miles. During the first 3 months, part of the road was in very bad condition and the tire cost was excessive. After this part was repaired the road was in fair condition, but never good. There were no excessive grades or bad sand, but wagon ruts, too narrow for the truck wheels and of a different gage, caused heavy tire loss; while chuck holes, sharp curves and stones, both imbedded and loose, were objectionable features. During wet weather the trucks could not get sufficient traction to climb some of the hills and were likely to stick in the mud in certain places, so that no attempt was made to run them unless they were on the' road when the rain started. This lost time amounted to about 5 per cent. of the total, but, whenever possible, it was utilized in making minor repairs. The price of gasoline was from 17 to 21 c. per gal. Rubber tires were used throughout. Drivers were said $4.50 to $5 per shift, and a return trip to Tucson was counted as two shifts even when made in one day. Drivers were provided with a room in Tucson and were paid for a11 time lost due to causes beyond their control. Trucks were loaded one way only. Speedometers were placed on both trucks but the excessive vibration soon caused them to fail. For this reason, and because no account was taken of the distance covered in picking up a miscellaneous load or in other minor ways, the mileage given is under the actual distance traveled. Some of the weights had to be estimated, but care was taken to have the number of ton-miles low rather than high, to avoid underestimating the costs. The cost of hauling from Tucson to the mines was $12 per ton

Jan 1, 1917

By P. W. Neurath, R. E. Waite

INFORMATION is available on the effect of stress on permeability, coercive force, and hysteresis for a variety of materials' but for the technically important grain-oriented 3 pct Si-Fe' the stress effects are not adequately covered in the literature; in addition, most of the stress data do not permit estimation of what would happen to the 60 cycle watt losses of the material under stress. Direct measurement of these effects therefore has been made and appears to be of considerable theoretical as well as practical interest. Losses were measured on the central 25 cm portion of 40~3~0.035 cm samples which could be stressed in a small tensile machine built for this purpose. Under tension the following effects, illustrated in the figures by a particular example, were observed: 1—"Unstrained" material of commercially acceptable loss level shows no change or a small increase in loss at low elastic stresses. For the sample shown in the figures, this is illustrated during the initial run, where a 7 pct increase is observed (Fig. 1). 2—There is no additional change in loss when the sample is further strained up to the elastic limit (Fig. 1). Within that limit the loss-stress curve is reversible. This is not illustrated in Fig. 1. 3—Even in the plastic range only small increases in loss are observed as long as the sample is kept under stress (Fig. 2, point N); often no increase can be observed (Fig. 1). 4—A large increase in watt losses is observed after removal of the stress subsequent to plastic deformation (Figs. 1 and 2). 5—All, or nearly all, of the foregoing increase in loss due to plastic deformation can be eliminated by a reapplication of tensile stress but returns upon removal of this stress. This is illustrated in the third run (Fig. 3). This run remains within the elastic limit and shows the reversibility of the stress-loss curve under this condition. These findings have been confirmed on large Samples (approximately 200~10~0.035 cm and larger) except that under 1 no initial increase in loss was ever observed on these. The accuracy of the watt loss measurements is of the order of 1 pct. Neither bending of the sample in the tensioning device nor a redistribution of flux along the width of the sample accounts for these results. They therefore must be explained on the basis of either a change in the domain configuration due to stress or a change in the domain wall mobility. Acknowledgment The assistance of Mr. Robert L. TenBroeck with the instrumentation is gratefully acknowledged.

Jan 1, 1956

By Clarence Zener

IT has long been known that the density of a metal usually decreases with cold-work. Thus O'Neill1 observed as early as 1861 that cold hammering of commercial hot-rolled copper is accompanied by a decrease of density of 0.2 per cent, and that subsequent annealing restores the original density. The origin of this density change, however, has remained obscure. In particular, experiment has not yet decided whether it is due to the presence of small cavities and an increase in intergranular surface or to an actual expansion of the lattice itself. This uncertainty in the origin of the change in density is a reflection of our uncertainty as to the changes induced in a metal by cold-working. One school regards cold-working as a breaking up of the original grains into a large number of perfect crystallites somewhat randomly orientated with respect to one another.2 According to this viewpoint, the mere introduction of a large intercrystallite surface induces a net volume expansion. Another school regards cold-working primarily as a distortion of the grains. It is not obvious that this second viewpoint will lead to a net volume expansion. The purpose of the present paper is to show that this is indeed the case, and that this expansion is of the right order of magnitude to explain existing experimental data. The physical basis for the association of an expansion with distortion lies essentially in the variation of the elastic moduli with volume. This variation is considerable. Thus from Table I we see that a I per cent increase in volume for the case of copper will decrease the bulk modulus K by i0 per cent, the shearing modulus µ by 3.8 per cent. If we thus twist a rod through a given angle, we shall do less work upon it if it increases slightly in volume, thereby reducing the torsion modulus that involves as a factor the shearing modulus. A general principle' in physics states that the rod will so adjust itself as to have a minimum potential energy consistent with the end restraints. It will therefore expand. [ ] In order to obtain a quantitative comparison with experiment, we follow Maier4 in comparing the lattice expansion with the latent energy of cold-work. This latent energy has been measured directly by Taylor and Quinney5 on copper rods subjected to torsion, and may amount to as much as 15 per cent of the total work done upon the specimens. We shall assume that this

Jan 1, 1941

By R. A. Kinzie

THE major operating costs in a cement plant are labor, power, and fuel. The opportunities and methods of savings in labor and power parallel other industries. Because our industry's use of fuel is large and its method of use is unique, the devices adapted for saving fuel are of interest. In normal practice the raw material in the form of a dry powder or a mud is fed to a rotating inclined cylinder where it is dried, calcined, and clinkered. In a Lepol kiln the raw material is rolled up into little balls with water in the nodulizer, fed to a traveling grate on which it is dried and partially calcined and tben to a short kiln where the process is finished. The more usual methods of saving heat have been the use of long kilns with chains in wet process plants and the use of waste heat boilers in dry plants (fig. 1). At the Santa Cruz plant we have used a Lepol system kiln and achieved a fuel 'economy of 4.7 gal per bbl of clinker or about 704,-000 Btu per bbl. This can be compared with our old kilns using the same fuel and raw material which consume 7.8 gal per bbl or 1,130,000 Btu per bbl. These are gross Btu and not the net figures usually used in reports of foreign companies. Our average consumption for 1948 was 708,000 Btu per bbl of Lepol clinker, based on cement sold, and oil purchased. The overall fuel consumption for 1948 was 6.61 gal per bbl. The Lepol system consists of a nodulizer, a grate, and a kiln. There is the usual accessory equipment which is similar to that used in other cement plants. The following description covers the equipment in operation at our plant. The nodulizer is a cylinder 8 ft 10 in. in diam by 18 ft long set on a slope of 1/2 in. per ft, and rotated at about 10 rpm. It is driven by a 50 hp wound rotor motor drawing about 9 kw. The inside of the shell is cleaned by a continuously operating scraper which draws 0.1 kw. The dry raw material is fed to the nodulizer where, being sprayed with water, it rolls into small spheres about 90 pct being between 1/2 and 1 in. in diam and containing about 15 pct water. The nodules fall on the traveling grate where the hot gas from the kiln is pulled down through the

Jan 1, 1951

By James Norman, O. C. Ralston, John Dasher

Most mineral products are used in the finely divided state, but some are sold in larger sizes. Coal, gravel, metallurgical fluorspar, phosphate rock, hematite, chro-mite, and other products are sold in sizes coarser than can be treated by many mineral-dressing methods. Gravity separation of coarser sizes by log washing and jigging is probably as ancient as any process now in use. The performance of jigs on a feed with sufficient difference in density of the minerals is excellent, but many families of minerals are too similar in density to be separated effectively by this method. The use of heavy suspensions of fine solids to separate coarse coal from bone and slate has been in use for some years. This separation by sink-and-float was limited until recently to light minerals. Development of galena and ferrosilicon as suspension media, by Minerals Beneficia-tion, Inc., at Mascot, Tenn., Pitcher, Okla., and Crosby, Minn., under patents granted during and since 1938, has permitted excellent results to be obtained on minerals of very similar densities up to 3.3. This process has been put In the hands of American Cyanamid Co. for exploitation, and further research now in progress may increase the density of suspension obtainable so that separations at a density of 4.0 may be practicable before this is published. The Huntington-Heberlein dense-medium process, developed in England, is also being commercialized in the United States by Sink and Float Corporation. Du Pont has developed a sink-and-float separation using halogenated hydrocarbons as parting liquids; at this writing, the method is used commercially only on coal but has been successful in the pilot plant on many other minerals using tetrabrom-ethane at densities up to 2.95. While these processes were being developed to extend the range of separation by difference in density to the coarser sizes, the Bureau of Mines was engaged in developing a process that will extend the range of separation by difference in wettability up to 2-in. size. War work has pushed aside its further development indefinitely. The results are published here with the hope that some use may be suggested that will justify post-war development, and so that readers that may be able to make immediate use of the scheme may have the information. Earlier Work It has been known since the time of Herodotus (B.C. 484(?)-425) that water-repellent particles will adhere to sticky surfaces. That early historian reports the recovery of gold from the mud of a lake

Jan 1, 1943

By R. H. Dourson, B. H. Sage, W. N. Lacey

The compositions of coexisting phases in the methane-propane-n-pentane system were determined at 160° and -2 20°F. throughout the two-phase region, at pressures above 500 lb. per sq. in. The experimental results permitted the calculation of gas-liquid equilibrium constants as well as the establishment of the critical behavior of this ternary system. Although many binary paraffin hydrocarbon systems have been investigated, the experimental work relating to the phase behavior of ternary paraffin hydrocarbon mixtures at elevated pressures is relatively scarce, being limited to a study of the meth-ane-propane-PL-pentane system at 100°F.l,2 However, Guter and co-workers have studied the phase behavior of the methane-ethane-ethylene system at relatively low temperatures. Information concerning the phase behavior of ternary systems is of value in predicting the behavior of the components in multicomponent systems, since the influence of pressure, temperature, and concentration may be individually ascertained. In the light of the importance of such information, the study of this ternary system was extended to higher temperatures in order to increase the field of temperature in which the data could be applied. Since all states encountered in this investigation are above the critical temperature of methane, the details of its phase behavior are not of direct significance. The properties of propane in the heterogeneous region were taken from a correlation3 based upon recently published data. The corresponding information for n-pentane was taken from experimentally measured vapor pressures and volumetric data.4 The rnethane-propane system has been studied throughout the two-phase region at temperatures above 70°F.,5 while the phase behavior of the propane-n-pentane system has been established for temperatures above 160°F.6 The volumetric and phase behavior of the methane-72-pentane system has been studied in detai1.7,8 The experimental measurements serve to establish with adequate accuracy the phase behavior of the components and of the constituent binary systems for this ternary system. It is believed that, with the exception of the measurements for the methane-propane system, the uncertainties in the earlier data relating to the pure substances and the binary mixtures are probably less than those associated with the values reported here. Method The methods and apparatus employed in this investigation have been described.137 In principle, the method involved the withdrawal of samples of the coexisting gas and liquid phases from a vessel containing a heterogeneous mixture of methane, propane and n-pentane. Provision was made so that

Jan 1, 1943

By W. N. Lacey, R. H. Dourson, B. H. Sage

The compositions of coexisting phases in the methane-propane-n-pentane system were determined at 160° and -2 20°F. throughout the two-phase region, at pressures above 500 lb. per sq. in. The experimental results permitted the calculation of gas-liquid equilibrium constants as well as the establishment of the critical behavior of this ternary system. Although many binary paraffin hydrocarbon systems have been investigated, the experimental work relating to the phase behavior of ternary paraffin hydrocarbon mixtures at elevated pressures is relatively scarce, being limited to a study of the meth-ane-propane-PL-pentane system at 100°F.l,2 However, Guter and co-workers have studied the phase behavior of the methane-ethane-ethylene system at relatively low temperatures. Information concerning the phase behavior of ternary systems is of value in predicting the behavior of the components in multicomponent systems, since the influence of pressure, temperature, and concentration may be individually ascertained. In the light of the importance of such information, the study of this ternary system was extended to higher temperatures in order to increase the field of temperature in which the data could be applied. Since all states encountered in this investigation are above the critical temperature of methane, the details of its phase behavior are not of direct significance. The properties of propane in the heterogeneous region were taken from a correlation3 based upon recently published data. The corresponding information for n-pentane was taken from experimentally measured vapor pressures and volumetric data.4 The rnethane-propane system has been studied throughout the two-phase region at temperatures above 70°F.,5 while the phase behavior of the propane-n-pentane system has been established for temperatures above 160°F.6 The volumetric and phase behavior of the methane-72-pentane system has been studied in detai1.7,8 The experimental measurements serve to establish with adequate accuracy the phase behavior of the components and of the constituent binary systems for this ternary system. It is believed that, with the exception of the measurements for the methane-propane system, the uncertainties in the earlier data relating to the pure substances and the binary mixtures are probably less than those associated with the values reported here. Method The methods and apparatus employed in this investigation have been described.137 In principle, the method involved the withdrawal of samples of the coexisting gas and liquid phases from a vessel containing a heterogeneous mixture of methane, propane and n-pentane. Provision was made so that

Jan 1, 1943