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By HAROLD A. KNIGHT

The Miami Copper Co., Arizona, is asking Congress to reimpose the import duty of two cents per pound on copper which, by law, has been suspended until June 30, 1950. C. Donald Dallas, chairman of Revere Copper and Brass, champion of a duty-free regime as regards the red metal, has been answering E. H. Westlake, Miami president, now that Mr. Westlake's statement to stock- holders has been salted away for posterity on wire recorders. Even prior to this action and at the instigation of two prominent consumers of pig lead, the House of Representatives has, in the confines of committee, not yet reported out, as of June 16, a bill to suspend the duty on lead for another year from expiration of the present law June 30, 1949. But apparently the bill was started too late. Thus the tariff issue becomes a Rip Van Winkle again after having slept for several years in the mountains of metals scarcity. During the wartime scarcity and the boom days that followed, most metal producers welcomed a considerable influx of foreign metal since it gave them a little surcease from constant teleibhone calls asking why that delivery of 300 tons of lead, 250 tons of zinc, and 1000 tons of copper had been delayed. These were the days when it was such an undisputed sellers' market that the sellers had even thrown away their certificates of ownership. Another development that brings home the tariff situation, small in it- self but perhaps indicating a trend, has been the announced closing of

Jan 1, 1949

By Frederick Laist

IN the course of the past 75 years the treatment of copper ores has undergone the most profound changes. To a lesser degree, this is true of all the nonferrous metals, but the rapid increase in the demand for copper due to the phenomenal growth of the electrical industry, and the discovery of vast new ore deposits in Michigan, Montana and Arizona, provided an exceptional incentive for improvements in smelting practice and for large-scale operations. Because these must perforce be carried on in regions where labor was scarce and wages high, the need for mechanization and larger smelting units soon became apparent. At a later date the porphyry coppers were discovered, with ores so low in grade that enormous tonnages had to be treated daily if they were to be made to pay at all. In some instances these ores were associated with, or overlain by, oxidized ores, which could not be concentrated mechanically and, of course, could not be smelted directly. This led to the development of the copper-leaching process. While the principles of the various smelting and leaching processes are for the most part of European origin, and have long been known, modern practice is essentially American and was evolved on this side of the Atlantic. The ores of copper may be divided into three general classes; viz, native copper, sulphide and oxidized ores. By far the greater number of commercially important ore deposits come under the classification of sulphides. Commercial deposits of native copper are limited to the Lake Superior

Jan 1, 1947

By I. Iwasaki, P. L. De Bruyn

Electrical double-layer properties of the silver sulfide-solution interface in different electrolytes and the influence the properties exert on the adsorption of dodecylammonium acetate (DAA) were studied using an electrochemical titration technique. The flotation behavior of silver sulfide was observed using DAA as collector and the results were correlated with adsorption measurements. Silver and sulfide ions were identified as the potential determining ions and their adsorption densities were measured as functions of the pAg and of the ionic strength at two different pH values. The point-of-zero-charge (PZC) was observed to be at pAg 10.2, the value being independent of pH and of the nature and concentration of the electrolyte used. The surface charge of silver sulfide in these electrolytes was positive for pAg values less than 10.2 and was negative for pAg values greater than 10.2. The adsorption of amine on silver sulfide surfaces at pH 4.7 was found to be strongly dependent on the pAg. A shift in the PZC towards a lower pAg due to the adsorption of amine indicated a specific affinity of dodecylammonium ion towards silver sulfide surfaces. At pH 9.2 a strong adsorption of the undissociated amine molecule was indicated. The PZC shift towards a higher pAg and the adsorption of the amine was virtually independent of the interfacial electrical conditions.

Jan 1, 1972

By PAUL P. ZElGLER

Rapid growth of the aluminum industry continued through 1948 with an acute shortage of the metal in all forms marking the year. Estimates based on shipments made during the first nine months indicate that, in 1948, the industry shipped more than two billion pounds of aluminum products or roughly four times the amount shipped in the greatest peacetime year prior to the war. The rapid expansion of the aluminum industry is particularly reflected in the production of sheet. Last year, the industry as a whole shipped an estimated 40 per cent more sheet than was produced in the peak war year of 1944.

Jan 1, 1949

By Morris J. Elsing

FOR MANY YEARS lead and zinc have had the so-called protection of a tariff and it is the purpose of the following brief discussion to show what' such protection actually accomplishes with a view to forecasting the possible results of the present copper tariff. In analyzing the subject, tabulations of the United States production, consumption, imports and exports, including ore and concentrates and all of the metallic products, of both lead and zinc have been made for each year since 1900. Of these data, the relationship of the imports and exports and the relative foreign and domestic prices are shown in Table 1. The conclusions drawn from these figures are listed below. 1. The United States is an exporter of zinc. 2. The United States is an importer of lead. 3. The average price of zinc at St. Louis for the last 32 years has been no higher than on the London market even though zinc and zinc ore have "enjoyed" a protective (?) tariff of varying amounts per pound for 22 years of this period. 4. The average price of lead on the New York market for 32 years has been 1.2c. per pound higher than on the London market, the tariff varying from 0.75 to 1.5c. per pound of lead in ore, and 1 to 2c. or more on manufactured lead.

Jan 1, 1932

By G. R. M. Del Giudice

The term "slime-coating" is not new in the art of flotation; the phenomenon has been observed and described by Taggart;(l)† Taggart, Taylor, and Ince;(2) and by Ince.(3) Notwithstanding that flotation was introduced for the treatment of finely crushed ore, the adverse effects of slimes have been recognized since the earliest days of the process, and the Elmore, Delprat, Potter, and other processes actually specified desliming of the ore prior to treatment. The cause of this trouble has been studied and described by Taggart;(1) Taggart, Taylor, and Ince;(2) Ince;(3) Morrow and Griswold;(4) and by Gaudin and Malozemoff.(5) Old Theory of Slime-coatings At present, so far as published work shows, there seems to be but one theory for the mechanism of slime-coatings. Ince(3) states that they are due to attraction between electrostatic charges of opposite sign on the sulfide and on the slime particles, supporting this theory by migration experiments in the Burton tube. He also used the microscope in conjunction with a glass cell employed by Beans and Eastlack(6) in studying migration, but met with interference from endosmosis. Several attempts have been made in the Department of Mineral Dressing at Columbia University to duplicate Ince's experiments with the Burton tube, but the results have never been convincing. Formation of precipitates which settled through the pulp levels, and evolution of gas at the electrodes, which disturbed the interface between the pulp and the distilled water above it, seriously interfered with observations. However, by use of the migration cell shown in Fig. 1, endosmosis effects and the disturbances due to precipitation and gas evolution were avoided, and distinct and reproducible migrations or absence of migration were observed. The cell was made of bakelite and had platinum electrodes. Objectives were employed which had a working distance of at least three millimeters,1 and the parts of the mounting which came in contact with

Jan 1, 1935

By C. Norman Bowers, Blaine B. Wescott

MARKED improvement in the serviceability of sucker rods has been effected in the last two years, partly because of the insistent necessity for greater economy in the operating costs of crude oil production growing out of the general industrial depression and partly because many of the recently developed fields have imposed more severe operating conditions upon both surface and underground equipment. The latter is particularly true of Kansas, where practically all of the oil produced. is associated with damaging amounts of hydrogen sulfide brine and where the method of establishing potential production demands equipment capable of being operated at maximum capacity without interruptions. The decline of flush production in the Oklahoma City field created new problems in deep-well pumping on a scale heretofore unequaled and the increased proportion of water it has been necessary to produce in the fields of the Greater Seminole area presented conditions that were acutely in need of betterment. The problem in the latter fields was complicated by the shift towards sulfide characteristics, which accompanied water encroachment, and it is probably true that nowhere, at the present time, are pump¬ing conditions generally as severe as in this territory. The Mid-Continent district, therefore, has become the proving ground for the numerous materials that have been proposed for sucker-rod fabrication. The information that ultimately will be obtained from an unprecedented amount of field experimentation will pay ample dividends when the decline of East Texas increases the demand for the vast reserves of sour crude in West Texas. It is a rare occurrence in industry that the use of such a simple piece of equipment as a sucker rod presents so complicated a problem for solution. As proof of this, it is only necessary to consider the numerous types of sucker rods on .the market at the present time and contrast this condition with that of less than four years ago, when it was the common aim of manufacturers to develop a single sucker rod for all conditions of

Jan 1, 1935

By E. F. Kingsbury

One of the well-known and important uses of the noble or precious metals has been for electrical contacts. In fact, the elements of this group, comprising gold, silver and the six platinum metals, have been called "noble" because of their ability to resist heat and corrosion, properties which were early found to be of importance in good contacts. Of these, platinum and its iridium alloys, palladium, and silver, have been extensively used. In recent years the electrical industry has been responsible for about one-eighth of the total consiimption of the platinum metals in the United States. Information is not available as to what part of this one-eighth has been used for contacts but it is certainly an important one. Substitutes for Platinum During the past 20 years a considerable number of contact alloys have been proposed in the patent literature largely with the aim of more or less replacing platinum by gold or silver, and some of these alloys are finding increasingly widespread application as the reliability of their performance becomes established. From even the partial data at hand it appears that this substitution by the less precious metals has replaced at least one-half of the amount of platinum that the entire electrical industry would otherwise be consuming at the present time. While the subject is of considerable interest to the metallurgist it is even more so to the electrical engineer and it is surprising that the literature records no systematic and comprehensive investigation along these lines. Practically all the scattered work on noble metal contacts has centered around platinum as a standard and has had two more or less distinct aims. One of these has been the replacement of platinum by cheaper matcrials, and the other, the dcveloprnent of materials of superior electrical performance. The merit of a contact metal has been assumed to be dependent on its infusibility, and since thc more precious metals have the higher melting points there has naturally been an association of the two qualities in the sense that the more precious were

By C. R. Austin

IN a recent paper1 the authors presented information on a refinement of the Rohn type of creep test with data on pure iron that exemplified the behavior of the apparatus. The present paper extends that work to nickel and cobalt and to the examination of the comparative high-temperature properties of two widely used commercial alloys. Careful attention has been given to the effect of plastic deformation in decreas-ing creep rate, using the elementary metals iron, nickel and cobalt for purposes of analysis. In any, endeavor to develop new materials for high-temperature service one soon encounters a real problem as to the sort of test to be employed in evaluating the commercial possibilities of the alloys. At one time it was considered satisfactory to determine the tensile strengths at elevated temperatures and to use these values as a criterion for the commercial application of the alloys. More recently the proportional limit has been used as a means of classification. Data obtained from a form of bend test has also shown promise as providing a "merit index" of high-temperature serviceability.2 Koerber and Pomp3 state that since the influence of testing time is small, the high-temperature yield point of steel furnishes sufficiently reliable and concordant values up to about 350° C. (and a maximum of

Jan 1, 1934

By E. J. KENNEDY

THE annual dinner-dance was held in the large ball room of the Commodore hotel Wednesday evening. A total of 577 were seated at the dinner, over which President Eavenson presided as chairman and toastmaster. In introducing George C. Stone, the James Douglas Medalist, W. R. Ingalls outlined the former's association with the zinc industry. He said, in part In designing and building Palmerton, Stone erected a metallurgical monument and won the title of chief engineer of the New Jersey Zinc Co., with transferal to its New York office in 1900. There lie held forth in dignity, efficiency, and with appreciation until his retirement from active service in 1929. After a few years lie was diverted from the position of chief engineer for his company to the superior one of chief metallurgist and that gave to Stone his next big chance.... This was the conception of a research department and the ability to persuade his directors to adopt it. I shall not pretend to summarize the great things that afterward developed. I shall mention only the institution of the manufacture of lithopone in this country, the charging of the Wetherill furnace with briquets, the mechanicalization of the Wetherills, the accomplishment of continuous distilling, and most recently the introduction of reflux-refining.

Jan 1, 1935

By D. V. Fites

Criteria for deciding when rock should be ripped and what ripping equipment and techniques should be used in given situations are discussed in this article. The relation between ripper performance and seismic wave velocities in various types of rock is also discussed. The ripper is not a new tool. In fact, it dates back as far as the Roman Empire. The Roman's ripper-mounted on wheels and shaped something like a plow — was pulled by oxen and used to loosen the earth for the shovelers and basket carriers building the Appian Way. There are records of rippers being used in this country in railroad construction between 1860 and 1880. However, the ripper as we know it today did not appear until about 1930. Tractor-drawn models were in use in 1931 on the Hoover Dam project. At that time they weighed about 7500 lb and were pulled by tractors with about 75 flywheel hp and up to 30,000 Ib total weight. The chief shortcomings of trailed

Jan 1, 1969

Bailey, Lewis Newton, Master Engineer, Senior Grade, 4th Regiment, U. S. Engineers, Headquarters Company, died of pneumonia at Camp Merritt, N. J., on April 30, 1918. Baird, Louis, Lieut., Royal Field Artillery, British Army, died on the battlefield in 1915. Ballamy, John H., Capt., 103c1 Engineers, killed in action near Fismes, Aug. 9, 1918. Bowles, Martin F., 2d Lieut., Co. B, 355th Infantry, killed in action, Sept. 3, 1918. Burt, Andrew, died in active service, 1916. Cobeldick, William Morley, Royal Engineers, died from gas poisoning on Oct. 7, 1915. Dougall, Ralph,. 4th University Co., Princess Patricia Regiment, killed in action early in the war. Evans, Alfred Winter, Lieut.-Col., New Zealand Rifle Brigade, D. S. 0., D. C. M., killed in action on Oct. 12, 1917. Gordy, Sheppard B., died in service, Oct. 9, 1918. Gorman, Thomas C., Lieut., Canadian Engineers, killed in France, Mar. 18, 1918. Hague, William, 1st Lieut., Engineer Officers' Reserve Corps, died in active service, Jan. 1, 1918.

Jan 1, 1919

By Lewis Smith

CHROMIUM is one of the new metals, but considerable research has been required to determine an approximate record of its production from 1827 until the present. Its use in the form of pure metal is not extensive; of the chromite mined, about one-half is required for making ferrochromium, about two-fifths goes directly into refractories and the remainder is absorbed chiefly by the chemical trades. The industries that demand chromite for such uses are mainly in countries that produce little chromite, while the important chromite-producing countries are not generally consumers. The international flow of chromite is therefore of interest, as yell as the political and commercial control of resources of the metal.

Jan 1, 1931

By John M. Lovejoy

FEDERAL regulation of the petroleum resources of the nation has long been an interesting topic for discussion. A plan to accomplish Federal control has now taken definite form. At the request of the President of the United States, a bill to be known as the Petroleum Conservation Act of 1939 has been presented to Congress-H. R. 7372, offered by Representative Wm. P. Cole, Jr., and more usually known as the Cole bill. It is an act ostensibly designed to conserve our petroleum resources, through regulation of production practices. Hearings are being held currently by a subcommittee of the Interstate and Foreign Commerce Committee, in compliance with the request of the President to report the bill early in the next session of Congress.

Jan 1, 1939

By H. B. Pulsifer

This paper outlines a method for rapid production of flat,, granular surfaces on many of the medium hard alloys. Grinding wheels and fabrics on wheels are not used; the purpose is accomplished by rubbing on emery papers and on fine abrasives heaped on hand boards. The advantages of chromic acid in the solutions for etching nickel and copper alloys are explained. Steels may require an additional step in the mechanical smoothing owing to the lack of an ideal etchant. Chloric acid is a rapid etchant for steel. Thirty-six photomicrographs illustrate the steps in smoothing and the clearness with which structures can be rapidly exposed. New structures in low-carbon steels are announced. After a little practice, many materials can be finished within two or three minutes. CUPRONICKELS In the previous papers on the metallography of copper and magnesiurn which the author has presented to this Institute there has been an attempt to demonstrate the advantages of minimizing the mechanical work of surfacing and depending more on chemical means; the present paper continues the research into a still wider field. It is obvious that the success of a chemical method for smoothing and etching depends almost entirely on the use of a suitable reagent. The etchant must remove the surface granulations and outline the structures. A very special type of reaction between reagent and metal must be displayed. Promiscuous corrosion or the intensification of the attack about local couples formed by impurities or components must not be in evidence. There are several reagents that etch highly polished nickel and copper alloys very well. Acidified ferric chloride solutions, concentrated and dilute nitric acid solutions, and nitric and acetic acids in acetone have been used to good advantage for the purpose. However, if they are expected to etch rather deeply—that is, smooth as well as characterize— the results may be far from satisfactory. Advantages of Chromic Acid In a protracted series of experiments it has been found that the addit,ion of chromic acid may be of the most surprising benefit. The function

Jan 1, 1929

By H. B. Pulsifer

This paper outlines a method for rapid production of flat,, granular surfaces on many of the medium hard alloys. Grinding wheels and fabrics on wheels are not used; the purpose is accomplished by rubbing on emery papers and on fine abrasives heaped on hand boards. The advantages of chromic acid in the solutions for etching nickel and copper alloys are explained. Steels may require an additional step in the mechanical smoothing owing to the lack of an ideal etchant. Chloric acid is a rapid etchant for steel. Thirty-six photomicrographs illustrate the steps in smoothing and the clearness with which structures can be rapidly exposed. New structures in low-carbon steels are announced. After a little practice, many materials can be finished within two or three minutes. CUPRONICKELS In the previous papers on the metallography of copper and magnesiurn which the author has presented to this Institute there has been an attempt to demonstrate the advantages of minimizing the mechanical work of surfacing and depending more on chemical means; the present paper continues the research into a still wider field. It is obvious that the success of a chemical method for smoothing and etching depends almost entirely on the use of a suitable reagent. The etchant must remove the surface granulations and outline the structures. A very special type of reaction between reagent and metal must be displayed. Promiscuous corrosion or the intensification of the attack about local couples formed by impurities or components must not be in evidence. There are several reagents that etch highly polished nickel and copper alloys very well. Acidified ferric chloride solutions, concentrated and dilute nitric acid solutions, and nitric and acetic acids in acetone have been used to good advantage for the purpose. However, if they are expected to etch rather deeply—that is, smooth as well as characterize— the results may be far from satisfactory. Advantages of Chromic Acid In a protracted series of experiments it has been found that the addit,ion of chromic acid may be of the most surprising benefit. The function

Jan 1, 1929

By Frank Reiber

The study of earthquakes long ago developed the fact that by study-ing the travel .times of the various groups of waves from the same earthquake, as received on seismographs :it varying distances, major discont'inuities in the earth's crust, could be reasonably well defined. Using this original discovery, and adapting the mathematical methods originally devised in seismology for determining the depth below the surface at which such discontinuities occur, other investigators were able to develop a new branch of seismology which promises to be extremely useful in extending the boundaries of our information on local conditions Below the earth's surface. As an outstanding example of the applications of this work, we have the so-called " seismograph " exploration of the Gulf Coastal region, which has resulted in the discovery of a large number of salt domes, from many of which oil fields may be developed. The original seismological investigations, from which different major discontinuities in the earth's crust were deduced, as well as these later successful experiments in locating salt-dome structures, involve relatively simple problems. In each case we arc dealing with surface materials in which elastic waves will be propagated with a fairly definite velocity. Under this material we have something quite different', in which the elastic waves will be propagated with a much higher velocity. The transition from one medium to the other is likewise relativtly abrupt. For example, in the Gulf Coastal region the sedimentary formations have a velocity of 6000 or 7000 ft. per sec., while the velocity of elastic waves in the cap rock of a salt dome may exceed 15,000 ft. per sec. Under such conditions, delineation of the formation is a relatively simple matter, and, furthermore, there is very little opportunity for ambiguous results. Development of Elastic-wave Method The success of this Gulf Coast work immediately suggested the advisability of attempting to extend elastic-wave methods to a point

Jan 1, 1929

By Albert J. Phillips

SEVERAL important changes have been' made during 1933 in the compilation and distribution of technical literature to those interested in nonferrous physical metallurgy. The Institute of Metals, of Great Britain, announced that preprints of all its papers would be distributed monthly to all members in combination with their bulletin of abstracts. The A.I.M.E. has announced that it will distribute to all members of the Institute of Metals and Iron and Steel Divisions a monthly bulletin entitled Metals, which will carry preprints of all publications of interest to the members of these two divisions. The American Society for Steel Treating has declared its intention to change its name to the American Society for Metals in order to indicate the broader scope of its activities. The abstract service of Metals and Alloys has been improved and expanded, covering practically the entire field of metallurgical literature. These changes and innovations now provide unparalleled reference service entirely in the English language.

Jan 1, 1934

By Hans Allenius, R. T. Hukki

This paper describes in quantitative terms the effect of sharpness of classification on the performance of the closed grinding circuit. The analysis is based on a large number of laboratory experiments designed to simulate the two most common industrial closed grinding systems. The experimental results show quantitatively the degree of improvement achievable by more efficient classification. In an earlier paper1 the senior author has presented a trend showing qualitative analysis of mill and classifier performance in tile closed grinding circuit. According to this analysis, the master key to a major improvement appeared to be effective removal of finished fine material from the classifier sands, or in other words, improved sharpness of classification, leading simultaneously to a substantial reduction of the circulating load. One purpose of this paper is to present the results of a quantitative investigation of the closed grinding circuit. Another is to set forth the essential pertinent variables revealed by the quantitative experiments carried out by the junior author. In the two most common systems of closed-circuit grinding, (1) feed to the circuit is introduced into the grinding unit, normally the ball mill, operating in closed circuit with the classifier; or (2) feed to the grinding circuit is introduced into the primary grinding unit, normally the rod mill, discharging into the classifier in closed circuit with the secondary grinding unit, normally the ball mill. In the following discussion, these two systems are analyzed separately in the indicated order. BALL MILL - CLASSIFIER CIRCUIT The Test Apparatus and Procedure: The test appara- tus included: (1) a F 195 mm x 220 mm laboratory ball mill rotated at a speed 77% of the theoretical critical speed, and a 7-kg batch of F 20 mm-F 50 mm steel balls; (2) a conventional 65-mesh test sieve and a Ro-Tap sieve shaker serving as a classifier; and (3) a Permaran instrument manufactured by Outo-kumpu Co. for surface area determinations by the permeability method. As no continuous closed-circuit experiments could be brought about on a laboratory scale, the process was broken down into alternating grinding and sizing steps in such a way that the new feed plus the returning sands always formed a batch of 1000 gm. For each selected grinding period and for each selected sharpness of classification the basic steps were repeated six times. Steady-state conditions were then reached. Crystalline vein quartz was used as a test material. Feed to the process consisted of -10-mesh fraction of this quartz crushed in rolls. This fraction included 15% of-65-mesh material. Experimental Results: The general flowsheet is shown in Fig. 1. Table I gives the essential data obtained representing steady-state conditions under the indicated set of variables. The table is based on 110 grinding experiments, 440 screen analyses and an equal number of specific surface area determinations. Fig. 2 shows the relationship between the cumulative net energy consumption and the cumulative number of mill rotations as evaluated by separate experiments. Note that this relationship is not linear but is instead represented by a slight curve. The data given in Table I are presented in graphical form as follows: Fig. 3 shows the produced -65-mesh material in grams per minute vs. time of grinding in minutes; the sharpnesses of classification at 65 mesh were 100%, 75% and 50%. It is clearly indicated that the highest-capacity figures call for relatively short grinding times and for the sharpest possible classification. Fig. 4 presents the specific surface area on the final -65-mesh product in square centimeters per gm vs. time of grinding in minutes. In conventional mineral dressing processes, a final product characterized

Jan 1, 1969

Frank Clemes Smith, Deadwood, 8. D. (communication to the Secretary): The reading of Mr. Chance's interesting paper suggests a few ideas relative to his discussion of certain Black Hills gold-ores. Mr. Chance refers to his examination, in 1897, of " the (Carboniferous) limestone plateau-country which encircles the central area of the Black Hills," and says that " it had been generally assumed that the mineralization of this formation was confined to the northern area;" further, that he "found, however, a general mineralization, extending in zones or belts throughout the region," and that the ores, being more or less specially

Jan 1, 1900