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By C. W. Waidner

THE standard scale of temperature that it is attempted to realize in practice is the centigrade thermodynamic scale, as defined by Kelvin about the middle of the last century. This scale would be exactly realized with a perfect1 gas in an ideal gas thermometer, and is closely realized with the more permanent gases. From the departure of certain properties of these gases from those of a perfect gas, it is possible to deduce the amount of the departure of the temperature scales, defined by their use, from the thermodynamic scale. In nearly all the precise experimental work done during the latter part of the last century, it was necessary for the experimenter to establish his own gas-thermometer scale, and the labor involved in this was often greater than that involved in the prime object of the experimental work undertaken. The experimental difficulties involved in gas thermometry led to the establishment of temperature scales differing from one another by amounts considerably greater than could be accounted for by the differences in the properties of the gases used. Results were, therefore, expressed in terms of somewhat different temperature scales, snaking correlation of such results difficult and uncertain.

Jan 9, 1919

Jan 1, 1963

By Edwin Hopkins

The year of 1924, in Venezuela, has been one of especial interest. The figures for production marketed are not so impressive, but to the well-informed followers of the development, the ease with which this production has been obtained and with which it apparently can be increased at will merits most careful consideration. For several years, the oil world, especially in the financial centers, has been closely following the slow unfolding. of the' Venezuelan developments, which has been, and still is, one of the great pioneering achievements in the history of oil exploitation. Venezuela, from the first days of its recognition by geologists and financiers as a great future source of oil, has been a field for the enterprising vision of the larger capital groups. The laws of the country have been drafted with almost an inspired foresightedness that has favored the exploitation of the resources along constructive lines, which' has eliminated the irrational promotion schemes that accompany many of the oil developments in the United States. Developments have been exclusively in the hands of strong financial groups, who have followed a conservative policy with respect to the dissemination of detailed information concerning the geological findings and detailed production data. Within the last year, however, the rapid expansion of the production phase of the developments has been on such an important scale and has involved such a large and rapidly increasing personnel, that further restraint with respect to information of a general informative' nature can serve no useful purpose. Certainly, from the volume of references to Venezuelan oil affairs, which are now of almost weekly occurrence in the oil trade journals, the public must appreciate the fact that in Venezuela, and in the Maracaibo district in particular, a new oil region of the first magnitude is about to emerge from comparative obscurity and occupy a commanding position on the stage of world oil affairs.

Jan 3, 1925

Jan 1, 1894

By P. Pietrokowsky

RECENTLY a comprehensive investigation of the various sigma binary alloys was published by Duwez and Baen.1 It was shown that the following conditions are necessary for the formation of the sigma phase: (1) the difference in atomic diameters of the two alloying metals must not be more than about 8 pct; (2) of the two elements which form sigma, one must exhibit a body-centered cubic structure while the second metal must be face-centered cubic, at least in one of its allotropic forms. In addition, a tetragonal unit cell was proposed and powder patterns of six sigma phases were indexed for d spacings greater than 1.640 kx. Since the indexing, based on tetragonal symmetry, led to only fair agreement, the possibility of sigma being orthorhombic was investigated. Various methods for indexing orthorhombic powder patterns are de- scribed in the literature.' The method used in this investigation was a graphical examination of the differences in values of sin' 9 for the adjacent lines of the powder diffraction pattern. This method led to a complete indexing of the Cr-Co (60-40) pattern. Because of the strong similarity between the various sigma alloys, it was then possible to assign indexes to the patterns of Fe-Cr (50-50), Fe-Cr-Mo (30-30-40), Fe-V (50-50), Co-V (50-50), and Ni-V (50-50). The values of sin' 9 and indexes of the six sigma alloys, together with visually estimated intensities, are presented in table 1. In general, the similitude between the six patterns is quite good. For spacings greater than 1.75 kx a few differences are noticeable. In the Ni-V pattern, no (320) exists and the two strong lines (030) and (031) are separated by only two lines of lower intensity, unlike any of the other sigma patterns. However, very little is known about the Ni-V phase diagram and it is possible that the equal atomic percentage composition in this system lies in a two-phase region. At lower spacings there is a close analogy between the patterns. The planes

Jan 1, 1951

By W. F. Baldwin

The timing circuit generally employed in Carter Reservoir Behavior Analyzers consists of a synchronous motor driven cam which actuates a microswitch. A mechanically actuated timer of this type has several inherent disadvantages, among which are the following: 1. The first time interval may not be of uniform length, depending on the exact position of the cam at the conclusion of a previous run. 2. The positioning adjustments on the microswitch lever arms are critical and require periodic readjustment. 3. The mechanical system is subject to wear which will ultimately impair its accuracy. It was therefore considered desirable to devise an alternate method which would eliminate these difficulties without introducing others that would be equally troublesome. This note describes the design of an electronic timing device which has been incorporated in the analyzer constructed by the Field Research Laboratories of Magnolia Petroleum Co. The electronic timer circuit is built around a simple neon glow tube relaxation oscillator, the complete circuit diagram of which is shown in Fig. l. The operation of the circuit is as follows: Condenser C, is charged to the critical firing voltage of the neon glow tube VR-75 by battery B1 through resistors R1 and R2. When the neon glow tube fires, the condenser C, is discharged, The charging cycle then repeats itself,

Jan 1, 1950

By James L. Martin, Daniel J. Martin

The dendritic pattern of steels shown by deep etching is used extensively as a guide in the inspection and control of the great majority of steels used in ordnance construction and for many applications in industry. The value of macroexamination lies in the fact that it enables a qualified observer to make deductions concerning the general quality of relatively large pieces of metal. Not the least of these general characteristics is the nature and extent of the dendritic segregation in the steel, either in the cast condition or after mechanical or thermal treatments. Previous Work Detailed methods for macroetching were outlined by Yatsevitchl and have been standardized by the American Society for Testing Materials. A comprehensive study of the occurrence, origin, and the chemical and crystalline nature of the dendritic structure was given by Keshiam2 The marked persistence of dendritic segregation in nickel steels is fully recognized and has been discussed by Sauveur and Reed3 and by others. Very little, however, has been written on the effect of the various elements on the macrostructure of steels, and the purpose of this report is to submit evidence concerning the influence of chromium, nickel and molybdenum on the macrostructure of some 4 by 4-in. ingots cast and treated under closely controlled conditions. Methods and Results The ingots to be described were made in a 60-lb. high-frequency induction furnace at the Watertown Arsenal. Heats were made from a single lot of materials; were molten for the same length of time; tapped at approximately the same temperature into a standard mold preheated in each case to 150º ± 10º C.; and stripped and buried in ashes after 10 min. in the mold. Transverse disks were taken from the same location in

Jan 1, 1939

The first meeting of the Naval Consulting Board was held at the office of the Secretary of the Navy, Washington, D. C., on Oct. 6, 1915. The Board organized by electing Thomas A. Edison, Chairman, Peter Cooper Hewitt, First Vice-Chairman, William L. Saunders, Second Vice-Chairman, and Thomas. Robins, Secretary. All of these officers are members of the American Institute of Mining Engineers. The other members of the Board are given below, and those who are members of the Institute are marked with an asterisk: *W. R. WHITNEY MATTHEW B. SELLERS. L. H. BAEKELAND. HUDSON MAXIM. FRANK JULIAN SPRAGUE. HOWARD T. COFFIN. BENJAMIN C. LAMME. ANDREW J. RIKER. R. S. WOODWARD. HENRY A. WISE WOOD ARTHUR GORDON WEBSTER. ELMER A. SPERRY. A. M. HUNT. *BENJAMIN B. THAYER. ALFRED CRAVEN. *J. W. RICHARDS. *SPENCER MILLER. *LAWRENCE ADDICKS. WILLIAM LE Roy EMMETT.

Jan 12, 1915

By G. G. Reed

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

Jan 1, 1986

By C. S. Sivaramakrishnan, Manjit Singh, Rajendra Kumar

Regarding liquid nzetals structurally as a suspm-sion of clusters , having derivated solid-state coordination, in truly liquid atoms, the recently developed Kuvlar-Samarin technique of centrifuging- in liquid state enabled the determination of the cluster sizes inAl-Cu mid Pb-Sn systems. It is shown that the colutne fraction of the clusters does not exceed 9 pct and the energy of their formation in Al-Cu is about 5.5 kcal per g-atom and in Pb-Sn eutectic alloys about 25 kcal per y-atoni. STRUCTURAL investigations of liquid state have principally followed the following three courses: i) studies with X-ray, electron, or neutron diffraction; these investigations have shown that there is a certain amount of regularity in the structure of liquid metals which can be defined by a coordination number and that the structure is a derived function of that in the solid state; ii) thermodynamical investigations which are based on the concept of ideal behavior; these describe the liquid state in terms of free-energy values and other thermodynamic functions; although these investigations are of help in the study of the general effects of alloying, they do not provide any structural insight into the precise atomic distribution in liquid state; iii) measurements of surface tension and viscosity; although it is natural to expect that the viscosity is related to the structure in liquid state, these investigations have so far only provided information which can be used by the foundry technologists and has been little utilized in formulating models of the structure of liquid state. As it happens, investigators in the three groups have worked almost independently of each other and there is practically no structural correlation between the results of one group with those of another. The purpose of the present paper is to indicate that the experimentally measured parameters of these three groups of research are closely related to the structure in the liquid state. STRUCTURE OF LIQUID METALS Although atomic distribution in solid and gaseous states is rigorously known, that of the liquid state is only appreciated on the fringes. There is no universal model of atomic distribution in liquid state, but two diverse models are at present hotly contested. The first, largely expounded by ~ildebrand,' regards the liquids as condensed gas since many of their properties and much of their behavior can be adequately described by regarding them as fluids. The second mode12j3 considers that some form of near-solid as- sociation of large number of atoms exists in the liquid state. On the other hand, ~ernal' was able to predict rather precisely the radial distribution functions in liquids on the basis of statistical geometric approach which considered that liquids are "homogeneous, coherent, and essentially irregular assemblage of molecules containing no crystalline regions or holes large enough to admit another molecule". He introduced the concept of pseudonuclei in the otherwise random structure as aggregates of closely packed tetrahedra which gradually merge into irregularity and continually replace each other. To what extent the pseudonuclei can be regarded as regions of near-solid association is indefinite but Bernal suggested that the concept of pseudonuclei can be compromised with the latter model if the near-solid associations are regarded as extremely dense and not necessarily crystalline. The difficulty in projecting the structure of liquid metals arises because they exhibit duplicity of character as some of their properties are closer to those of crystalline solids and others to fluids. There is an increasing tendency to discuss the structure of liquid metals in terms of the second concept according to which the structure of liquid metals may be conceived as consisting of i) clusters of atoms where the aggregation is a close derivative of that in the crystalline state, ii) individual atoms which behave like true liquids in respect to degrees of freedom and iii) excess number of vacancies. It is noteworthy that the introduction of only 5 pct vacancies is sufficient to transform crystalline matter into the liquid state. At any instant of time thermodynamic equilibrium exists between i, ii, and iii, but the relative proportion of the clusters and random atoms is not known. That this is so can be appreciated by the fact that, when liquid metal is rapidly cooled, liquid state vacancies may condense in the form of dislocation loops and vacancies in excess of their equilibrium number in solid state. These dislocation loops have been observed in thin foils of aluminum prepared from rapid cooled aluminum. As temperature increases above melting point the number and volume fraction of clusters decrease but those of vacancies and random atoms increase. Clusters are transient in nature. In pure metals the cluster is an aggregation of the metal itself. In alloys, however, the nature of the cluster largely depends on the interaction between solvent and solute atoms. If the interaction between unlike atoms is greater than between like atoms: the clusters are then aggregates of unlike atoms. Examples of this kind of system are A1-Cu, Mg-Pb, and so forth, i.e., systems which exhibit negative departures from the Raoult's law. In systems where the interaction between unlike atoms is smaller than be-

Jan 1, 1968

By G. E. Karantzavelos

Anew flotation process to recover alunite from low-grade alunite ores is described. The process begins with run-of-mine ore, reduced to less than 5 mm (0.2 in.), being preconditioned with the reagents before grinding and alunite flotation. From the preconditioning step, ore particles, impregnated with reagents, form pellets that subsequently disintegrate into the pulp during grinding. The second step is basically a standard alunite flotation step. Pilot plant test results show that an alunite concentrate assaying at least 85% alunite and less than 5% silica can be produced. Laboratory and pilot plant results were in excellent agreement, indicating that the new process is a viable means of alunite beneficiation. Plant results, using the new process, were superior to results from conventional alunite flotation procedure.

Jan 1, 1986

By H. R. Shidel

THIS paper summarizes the results obtained from the preliminary cementing of wells in an effort to cut off the bottom water. The object of this work was two-fold: (1) To prevent the oil sand from becoming flooded. (2) To plug off bottom water, thereby preserving the individual well and reclaiming production. Valuable suggestions and help have been given by the following named: Messrs. Kyle and La Velle, of the U. S. Bureau of Mines; Magnolia Petroleum Co.; Freed Oil and Gas Co. The cementing work was carried out under the personal supervision of L. J. Snyder. In an unpublished paper on the "Water Problem in the Augusta Field," S. K. Clark reaches the following conclusions: (1) That the great amount of water present is bottom water, occurring in the Varner sand, the main producing or the 2500-ft. horizon. (2) That the only striking connection between structure and water is in the area of the marked fault on the Ralston, E. C. Varner, and F. Varner leases in sections 8, 9, 16 and 17. (3) That the oil occurs in porous streaks, generally separated by fine-grained, well cemented sand, which is barren. Possibly two, or three such pay streaks may be found. That under a pay, fine-grained sand occurs, which is presumably barren at the time of drilling, but soon reveals water. The writer takes partial exception to the last point, because well defined shale, slate, lime, or hard sand breaks have been encountered in a great many cases, separating the pay streaks under which water is often found. This is not an invariable occurrence, as cases have been noted when the oil has been followed immediately by water in the same stratum. In an effort to overcome the water menace, the following methods of plugging were tried: (1) Plugging with wood, lead, and limit plugs. (2) Plugging with sand pumpings.

Jan 10, 1918

By D. L. Katz

The critical phenomena have been studied during the past century but our knowledge of the critical temperatures and pressures of complex hydrocarbon mixtures still is very limited. The critical temperatures and pressures of pure substances have been examined in large num-bers,20 and in great detail.11,17 No experimental determinations of the critical phenomena have been reported on such complex hydrocarbon systems as a reservoir fluid. The critical temperature is defined by Taylor18 as follows: "there is some temperature for each gas above which the gas cannot be liquefied. This temperature is called the critical temperature." The critical pres-sure of a pure substance is the vapor pressure at the critical temperature. It should be noted that these definitions refer to a given substance in the pure state and do not mean that the pure substance cannot be liquefied in the presence of a second constituent. The normal procedure for obtaining the critical temperature of a substance is to heat it in a glass tube 1,20 under pressure until the meniscus between the liquid and vapor phase disappears, although other methods, especially for mixtures, have been used. 11,14 However, when considering oil and gas reservoirs, it is more enlightening to consider a critical phe-nomenon that occurs when a mixture of oil and gas are compressed at a reservoir temperature until the meniscus disappears because the two phases become equal in composition. This conception, along with erroneous applications of the definition of the critical phenomena of a pure substance to that pure substance when it is part of a complex mixture, has caused confusion even among persons familiar with the classical theories.

Jan 1, 1938

By J. R. Campbell

A DOZEN years or so ago, the general superintendent of our company, now the president, Mr. W. H. Clingerman, detailed me to make a study of the coal-washing problem and collect data, which threw me into contact with the best washery men of the country. and took me to those districts where the washing of coal for metallurgical purposes is carried out. I investigated many kinds of coal-cleaning schemes, made numerous tests on them, and collected voluminous data, yet I confess frankly that I have had but little practical washery experience and that little has been at the Middlefork washery of the United States Fuel Co. at Benton, Franklin Co., Ill., which was put in operation last fall. While this wash-cry installation may not be the "last word," I am quite sure it embodies some long steps in advance over older designs and constructions. From the washery man's standpoint, the removal of pyrites, or marcasite, a disulfide of iron, is the one vital problem, and the one productive of the most beneficial results, so far as elimination of sulfur is concerned. Sulfates and so-called organic sulfur occupy quite a secondary -position and are generally lost sight of in coal washing: The elimination of sulfur in coal in the past has usually been accomplished by jigging in water, but lately the use of concentrating tables has been employed with good success, and some mention may be made of the flotation process on fine coal, though hardly considered practicable. Coal washing, is rapidly coming into its own, due to the depletion of low-sulfur coals for coking purposes, and before many years we predict as careful attention being given to the design and construction of coal washeries, ,as is now being given to byproduct plants and other allied industries. Heretofore, coal washing has been considered only as an incidental and a necessary evil-instead of the big problem it is one worthy of the most careful study by men well trained along technical lines and capable of delving into the fundamental principles.

Jan 9, 1919

By J. J. De Witte, J. G. Cazort

The Paranam plant in Surinam (formerly Dutch Guiana) was built during 1939-40 to supply crushed and dried bauxite for the growing U.S. aluminum industry, supplementing production from the Suriname Aluminum Co.'s Moengo works, which began operation in 1922. A subsidiary of Aluminum Company of America, Suralco's total annual production from these two plants averages 2.55 million dry metric tons of various grades of bauxite. Starting in 1941 with bauxite from mines on the west side of the Suriname River, annual production at the Paranam plant has varied from a low of approximately 450,000 tons to more than 1 million tons in 1949. High production rates during World War II and the late 1940's rapidly depleted these reserves, and in 1950 plans were made to mine the known deposits on the east bank of the river, about five miles downstream from the original Paranam plant.

Jan 11, 1960

By William Y. Warren

Messrs. Thomas & Cross, having leased from the Akron Cement Company from twelve to fifteen acres of abandoned cement-tunnels and chambers, for the purpose of propagating mushrooms for the market, commenced operations about a year ago, and are now beginning to furnish mushrooms in quantities to the local markets of Buffalo and Rochester. The quarries, or, more properly, the mines, of the Cement Company are located at Akron, Erie County, PIT. Y. The cement-rock occurs in a stratum about 71/2 to 8 feet in thickness, which is overlain by from 1.5 to 25 feet of limestone and flint-rock. There is a gentle rise from the opening of the tunnel inwards, giving a natural drainage and leaving the chambers comparatively dry. The roof is good and is supported by pillars and heavy timbers. The mushroom-beds are located about 300 feet from the opening of the tunnel, and are made in the form of mounds about 3 feet by 12 feet, at the base, and 24 feet high, giving to the chambers the appearance of a subterranean graveyard. Many experiments have been made to determine the best form for the beds, and the mound

Jan 1, 1889

By Stephen Taber

A vein may be defined as an aggregation of mineral matter, more or less tabular or lenticular in form, which was deposited from solution and is of later origin than the inclosing rock. This definition differs from the one found in many text-books in that no assumption is made as to the origin of the space occupied by the vein or the manner in which the mineral matter was deposited. In the present paper the writer purposes to discuss the mechanics of vein formation, and does not wish to begin by begging the question. The origin of ore deposits has been diligently investigated in recent years, but, while much has been written concerning the chemistry of the process, the physical side of the question has received less attention. The source of the ore minerals; the chemical composition of ore-bearing solutions; the relative importance of magmatic and meteoric waters as agents of concentration; and the causes of mineral precipitation have all been discussed at length. On the other hand, little has been written concerning the mechanics of vein formation, and the theories given in text-books today are essentially the same as those developed by the early Cornish and Saxon miners. Early investigators often regarded both veins and dikes as igneous in origin, but today the theory that vein minerals have been deposited from solutions, either liquid or gaseous, is firmly established. The latter view is supported by the fact that many vein-forming minerals are not found in unaltered igneous rocks; by evidence obtained in the laboratory regarding the solubility of minerals; by the presence of many ore minerals in hot-spring waters; by the occurrence of some veins in regions consisting exclusively of unaltered sedimentary rocks; by evidence as to the temperature at which some minerals are formed; and by the absence of mineral segregation due to difference in specific gravity. There is still, however, much difference of opinion as to whether certain tabular-shaped masses should be classed as veins or as dikes. Some of the earlier investigators have also advocated the theory that veins are contemporaneous in origin with the inclosing rock, while others have believed the vein minerals to represent a recrystallization or transforma-

Jan 1, 1920

The following is an incomplete list of members and guests who called at Institute headquarters during the period June 10, 1919, to July 10, 1919. Anvil A. Anderson, Rapid City, S. D. Roy N. McBride, U. S. Army. R. Hay Anderson, Mexico City, Mex. R. S. McIntyre, Berkeley, Calif. W. A. Barnes, San Francisco, Calif. H. R. Maier, Brooklyn, N. Y. Bennett R. Bates, Denver, Colo. Wm. D. Mainwaring, Philadelphia, Pa. Harlan H. Bradt, Duluth, Minn. Wm. E. Milligan, Chrome, N. J. H. Brings, San Francisco, Calif. Willard S. Morse, Tacoma, Wash. Robert S. Burg, Ocean Park, Calif. Arthur Notman, Bisbee, Ariz. D. W. Butner, Congo Belge, Africa. P. Nugue, Chalon Sr. Saone, France. George A. Camphuis, El Paso, Tex. George A. Packard, Boston, Mass. Fred Canan, Denver, Colo. C. L. Petzel, New York City. Walter H. Coleman, Prescott, Ariz. V. Porreaud, Paris, France. Fred Crabtree, Pittsburgh, Pa. Fred S. Porter, Seattle, Wash. Ross E. Douglas, Rancagua, Chile. R. W. Prouty, Morenci, Ariz. F. A. Downes, Golden, Colo. Charles E. Prior, Brooklyn, N. Y. W. G. Eberhardt, Tucson, Ariz. Louis Ravicz, Minneapolis, Minn. Charles H. Fulton, Cleveland, Ohio. Wm. Reed, El Oro, Mexico. Wm. R. Grunow, New York City. E. J. Ristedt, Globe, Ariz. Orr R. Hamilton, Lansing, Mich. A. M. Rodgers, Middletown, N. Y. T. N. Havlin, St. Louis, Mo. J. C. Scoles, Salt Lake City, Utah. G. M. Henderson, Weston, Mass. C. E. Siebenthal, Washington, D. C.

Jan 8, 1919

By James Johnston

Synopsis.—A description of the working of the mills of this company and the metallurgical practice in vogue, by which a remarkably complex silver ore, averaging 54 oz. of silver per ton (run-of-mine ore), is treated to give a 95.66 per cent. extraction. The main features of the processes are: The cyanide amalgamation of the high-grade ore. The cyanide treatment of the low-grade ore, after extremely fine grinding and close classification, in a caustic soda solution. The use of a wet desulphurizing process to break up refractory silver minerals. The substitution of aluminum dust for zinc dust as a precipitant. The recovery and shipment of over 13,000,000 oz. of silver in bullion at 997 to 999 fine since this metallurgy was inaugurated, about 2.5 years ago. On the completion and successful operation of the mill to treat their high-grade ore,' the Nipissing Mining Co., under the general management of R. B. Watson, started a series of investigations of the possible treatment of the low-grade ore by the cyanide process, so that they would be in a position to market only silver bullion. These tests were run in July, 1911, on a large scale, by G. H. Clevenger, on an average mixture of Nipissing ore. The results obtained by a partiai amalgamation followed by cyanide treatment gave an extraction varying from 90 to 93 per cent. and were sufficiently encouraging to warrant Charles Butters, the company's Consulting Metallurgist, in recommending that the new low-grade ore mill under contemplation should be a cyanide mill, instead of a concentrator. The cost of such a mill, capable of treating 200 tons per day, to obtain a 90 per cent. extraction at a working cost of $3 per ton of ore treated, was estimated at $250,000. In coming to a decision as to which type of mill should be erected, the concentrator, with the subsequent shipping of concentrates to a smeltery,

Jan 1, 1915

By I. Iwasaki

The steel industry is facing an unprecedented challenge. I would like to point out the role that flotation technology could play in meeting this challenge by providing high quality raw materials to the steel industry. Of all the technology available to a blast furnace operator, raw material preparation is by far the most important. Raw material preparation has been a key to the success of the Japanese steel industry. The foremost proponent of better raw material preparation was Professor Joseph at Minnesota. He gave a Howe memorial lecture to the AIME audience in the early 1950s, prepared from the lecture notes that he gave in his classes. At about that time he was invited to Japan. It is ironic that the Japanese steel industry listened and made it a success. In order for our steel industry to be competitive, first we must supply high quality and uniform quality raw materials to improve the efficiencies of our blast furnaces. Where does flotation fit in to the iron ore industry then? First, as a primary means for concentrating for oxidized iron ores. Second, to touch up magnetite concentrates for the removal of the last few percent of silica. And third, in the preparation of super-concentrates for direct reduction.

Jan 1, 1984