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By Frank L. Antisell

Certain physical and chemical properties of copper are so intimately related that a change in variation of the physical properties indicates a certain chemical change. The standard specifications of copper of the American Society for Testing Materials are based upon physical characteristics with one exception, namely, the copper contents. The physical standard includes electrical properties, defects in the "set or casting," variation in dimensions, weight, etc. Paragraph 4 of the specifications states, " Wire bars, cakes, slabs and billets shall be substantially free from shrink holes, cold sets, pits, sloppy edges, concave tops, and similar defects in set or casting." Shrink holes and concave tops indicate both physical and metallurgical defects; cold sets, sloppy edges, etc., indicate physical defects only; small pit holes may be indicative of either or both physical and metallurgical defects, depending on conditions under which they originated. To the refiner, a copper casting, no matter how made, is known as a "shape," irrespective of whether it is wire bar, ingot, cake, slab, billet, etc. As practically all shapes are cast in an open mold, that is a mold without cope, the surface of the shape cools in contact with the atmosphere and has a coating of oxide. Certain phenomena of the surface indicate the adaptability of the metal for forging or rolling. The writer believes that it is much simpler to produce shapes that are metallurgically correct than those that are mechanically satisfactory. When copper is to be rolled into thin sheets or drawn into very fine wire, the slightest physical defect becomes evident. It is, therefore, of the utmost importance to consider every characteristic of the shape and ascertain the physical and chemical relationship. Pitch and Set.—The appearance of the surface of the copper when cooled is considered as to its "pitch," or the general contour of the surface of the shape (which may vary from a concave to a convex); and the '" set,"' or the detail appearance of the surface of the shape (the wave-like structure). When the shape presents a concave surface, it is known as "low pitch;" a convex surface is known as "high pitch" or "tough pitch;" and a level surface is called "flat pitch." The set of the copper is, in a very large measure, directly related to the pitch; and so intimately are

Jan 1, 1921

By H. H. Kellogg, T. R. Ingraham

Three anhydrous zinc sulfates have been identified. They are: ZnSO,(a), stable below 1007°K; ZnS04(/3), stable above 1007OK; and ZnO.ZZnSO,. The decomposition pressure of each sulfate has been measured and the following relations calculated from the results: The measured data have been combined with the known themzodynamic properties of ZnS, ZnO, Zn, SO,, and SO, to yield univariant and bivariant phase diagrams for the system Zn-S-0. The application of these diagrams to problems of roasting zinc concentrates is discussed. PRESENT knowledge of the equilibrium chemistry of the system Zn-S:O, so essential to scientific control of zinc-blende roasting, is deficient in several respects. A basic sulfate of zinc has been reported by many investigators, but its composition is in doubt and its thermodynamic properties have not been measured. Our scanty knowledge of the properties of the normal sulfate at roasting temperatures is based on old and inexact studies. A crystal transformation in the normal sulfate, involving a sizable heat effect, has been noted by several investigators but has never been quantified. The studies reported herein were designed to fill these gaps in knowledge and to make possible a reasonably complete thermodynamic description of the system Zn-S-0 at roasting temperatures. The results make possible a far more exact understanding of zinc roasting chemistry than was hitherto possible. EXPERIMENTAL The principal experimental technique employed was the measurement of the total gas pressure developed from decomposition of either ZnSO, or ZnO2ZnS0, in a closed system. The apparatus employed was essentially the same as that described by Warner and lngrahaml and Flengas and tngraham.' The unusual feature is a flexible Pyrex bellows used to separate the reaction gas mixture (S03, SOz, and 02) from the mercury in the manometer and thus prevent corrosion of the mercury by SO3. The bellows operates without evidence of hysteresis and, barring accidents, may be used for several months. The response of the bellows varies from manometer to manometer, but is generally of the order of 0.6-cm displacement for a l-cm change in pressure. The response for all manometers has been linear over the range 0 to 1 atm. To prevent condensation and polymerization of sulfur trioxide, the bellows-manometer was maintained at 100.0" * 0.5" by a circulating bath of silicone oil. The connecting tubing between the manometer and the furnace was maintained at 100.0" * 0.2"* also, with a stirred air bath. The open end of the manometer was connected with a chamber which was maintained at a known pressure. The pressure could be varied so that readings of the height of the mercury column, measured with a cathetometer, could be made with both rising and falling mercury column. By using the average of the readings, any error due to sticking of the mercury column was minimized. The sample was placed in a 2-in.-long platinum boat formed into the shape of a half-cylinder. The sample was prepared as a fine powder and pressed against the inner wall of the platinum boat. A silica thermocouple well, covered with a platinum sleeve, was placed lengthwise along the center of the boat. The temperature of the sample was read on a calibrated Pt-10 pct Rh theirnocouple. The temperature profile of the furnace was constant within ± 0.2 C over the length of furnace occupied by the sample. The horizontal furnace used to contain the sample and the quartz reaction tube was electrically heated, with the control thermocouple placed 1/4 in. from the windings. A Brown Pyro-O-Vane temperature controller with a 3-sec response time was used to maintain the furnace temperature. Before beginning a run, the apparatus, including the bellows manometer, was thoroughly washed in sib with acid and distilled water to remove any

Jan 1, 1963

By J. W. Fredrickson

VERY little information is available in the literature concerning the solubility of magnesium in titanium. Aust and Pidgeon&apos; report the solubility of titanium in magnesium to be 0.0025 pct at 650°C and 0.015 pct at 850°C. X-ray diffraction studies failed to detect any evidence of solid solubility. Based on the fact that the addition of titanium to magnesium increases the c/a ratio of magnesium, Busk&apos; suggested that the Mg-Ti system, like the Mg-Zr, is a peritectic. Eisenreich- eported the solubility of titanium in magnesium to be 0.003 pct at 655°C and 0.064 pct at 760°C. Removal of hydrogen from the melt increased the solubility of titanium to 0.115 pct at 800°C. Eisenreich proposes a peritectic-type diagram for the high magnesium side of the system. Recent work&apos; with Ti-Mg diffusion couples indicate that the solid solubility of titanium in magnesium is extremely small and that there is limited solid solubility of magnesium in titanium. Experimental work on the Ti-Mg system is complicated by the fact that the boiling point of magnesium is considerably below the melting point of titanium. Consequently, the usual alloying methods are impractical. Alloying was accomplished in this investigation by sheath-rolling compressed compacts." The alloys were made from titanium sponge and high purity magnesium. Chemical analysis of the sponge showed 0.04 pct Mg, <0.005 pct Al, <0.001 pct Cu, 0.05 pct Fe, 0.022 pct Mn, <0.0025 pct Ni, 0.007 pct Si, <0.005 pct V, and <0.01 pct Zn. All heat treating was conducted in a protective atmosphere by encapsulating the specimens in fused silica ampules under a partial pressure of helium. Equilibrium was achieved by holding the specimens at temperature for periods of 24 to 120 hr. The alloys were hot rolled, cold rolled, and annealed prior to solution heat treatment. Fig. 1 shows the constitutional diagram obtained for the Ti-Mg system up to 1.5 pct Mg. Oxygen was known to be present in the alloys; therefore, it is necessary to consider the alloys as ternary rather than binary and the diagram should be viewed as a plot of a section through the Ti-Mg-0 system. Other investigatorso have shown that the addition of oxy- gen to titanium stabilizes the a phase. The data presented in Fig. 1 indicate that the addition of magnesium to titanium tends to stabilize the p phase. Armour Research Foundation7 has shown that the addition of magnesium to zirconium lowers the a transus and is classified as a p stabilizer in that system. Magnesium is soluble in solid titanium to the extent of at least 1.5 pct in both the a and /3 phases. No intermetallic compounds or magnesium-rich phases were observed either by light microscopy or X-ray diffraction. However, this does not negate the possibility that such phases exist at higher alloy concentrations.

Jan 1, 1956

By C. L. Sainsbury

Lode and placer tin deposits of the western Seward Peninsula, Alaska, have produced more than 2200 tons of metallic tin and constitute the only known domestic deposits of economic grade and size. The lode deposits consist of quartz-topaz greisens containing cassiterite and wolframite as well as numerous base-metal sulfide minerals, and most are in or near altered biotite-granite that forms isolated stocks or in rhyolitic dikes near granite. Within the main lode-producing area in the central York Mountains, nonpegmatite beryllium deposits, consisting principally of fluorite, chrysoberyl, diaspore, tourmaline, and white mica, with minor euclase, bertrandite, phenakite, hematite, and todorokite, are distributed zonally around the tin deposits and locally are transitional with them. All the known beryllium deposits are replacement lodes in carbonate rocks. In the area discussed, both tin and beryllium deposits are localized in a structural belt striking N70° to N85°E across the central York Mountains. The belt is characterized by numerous normal faults, which cut extensive thrust sheets, and by dikes of rhyolite, rhyolite porphyry, and lamprophyre that were injected along the faults. Ore deposits are localized where the dikes intrude brecciated rocks beneath thrusts and, although complex in detail, form tabular lodes that tend to lie along the thrusts. The granites contain abnormal amounts of tin, beryllium, lithium, and boron, and the tin and beryllium lodes are believed to be genetically associated with these enriched granites

Jan 1, 1968

By J. Parke Channing

IT, HAS been my privilege to be Chairman of Engineering Council for very nearly three years, during which time Mr. A. D. Flinn, the. Secretary, and myself, have seen the organization develop until it is functioning smoothly and accomplishing what it can with the money at its disposal. The earliest attempt at what may be called an Engi¬neering Council, of which. I have any knowledge, was made six or seven years ago when the four Founder Societies each appointed two men, who occasionally met to discuss matters submitted to them which were of importance to, the, profession as a whole. I was one of the representatives of the American Institute of Mining Engineers.

Jan 1, 1920

By AIME AIME

HIS many admirers regard the "official"&apos; candidate for president of the Institute in 1934 as far above the average in ability and capacity; but perhaps his outstanding characteristic is dependability. Some men of great brilliance succeed indifferently because they cannot be relied upon. When Howard Nichols Eavenson undertakes to do something he either does it, or he proves to his own satisfaction that the particular object is not attainable. And the latter outcome is exceptional because his judgment is so good that he generally foresees the impossibility and selects in advance a practical alternative. Though a tireless worker he is pretty sure that his energy is not spent futilely.

Jan 1, 1933

By G. W. Healy, J. C. Schottmiller

Molten silicates were found to exist in the Cr-Si-0 system at temperatures above 1450°C. one atom of oxygen is readily removed from CrzOs in the presence of Si02 at 1700°C, forming a silicate melt. Steam-hydrogen ratio measurements made at this temperature indicate that the free energy of the reaction: Cr20s(c) + Hz = 2CrO (in Si02 -saturated melt) + H20 is approximately 5600 * 1500 cal. A deep-blue chromous silicate, probably Cr2Si04, forms from these melts at about 1400" to 1500°C, and is characterized by.its distinctive X-ray diffraction pattern and optical properties—distinct pleochroism and high refractive indices. THE question of the state of oxidation of chromium in slags has vexed metallurgists for many years The experiments of Koerber and Oelsenl suggested the probable presence of divalent chromium in silica-saturated slags equilibrated with high-chromium melts. Hilty and coworkers2 had also found chromium at lower valency, as Cr304, in inclusions formed from oxygen-saturated Fe-Cr melts with as little as 10 pct Cr. In both cases, disproportiona-tion of the lower oxide to CraO3 and chromium was found to occur to a greater or lesser extent, depending upon the rate of cooling from the high temperature. The work on Cr304 was sufficiently detailed for chipmans to derive its thermodynamic properties, but Oelsen&apos;s experiments in the silicate system were not extensive enough since most of his runs were made with slags containing large amounts of manganese oxide in addition to iron and chrome oxide and silica. The present study describes experiments carried out to map out an approximate liquidus diagram in the CrzOs, "CrO", SiOa portion of the Cr-Si-0 system, and to measure the partial free energy of solution of oxygen in the system. EXPERIMENTAL 1) Approximate Melting-Point Determinations. Preliminary trials showed that when an equimolar mixture of Cr20s and SiOa was treated with hydrogen in the temperature range 1500" to 1600°C, copious amounts of steam were evolved, and a low-melting liquid formed which could be quenched to a blue, crystalline, material having a distinctive X-ray diffraction pattern. It was found that the identical material could be produced by heating intimately mixed, finely divided Cra03, Cr, and SiOa, held in a tungsten crucible, under purified argon. Thus, it was possible to prepare mixtures containing any desired proportions of chromium, silicon, and oxygen, pel-letize them, heat to temperature in the furnace shown in Fig. 1, and observe, after cooling, whether the pellet remained unchanged or showed signs of incipient, partial, or complete melting. 2) Free Energy of Solution of Oxygen. This was studied by measurement of steam-hydrogen ratios for the reaction: H20 (gas) + O (dissolved in charge) + Ha (gas) The experimental method chosen was to prepare a

Jan 1, 1964

By Rafael Errazuriz

About eighty miles north of the city of Antofagasta, Chile, located just below the Tropic of Capricorn, there spreads a wide desert area where copper oxide outcrops can be seen with the naked eye. Numerous old mining works and dump heaps with the green of atacamite and chrisocolla shining in the blazing sun, attest to the work done by miners in the beginning of this century. The dry desert air preserves the footstep marks, paths and trails of old cartwheels from years back. The mining area known as Michilla and Panizos Blancos, is located on the high plateau at 3000 ft above sea level. Around 1920 a Bleichert ropeway was built, which carried ores from the best known mine to a wharf at the Michilla bay. High grade silicious ores were shipped to the Gatico Smelter further north or to smelters in the United States or Japan.

Jan 8, 1973

By Jos D. Weeks

On the extreme fringe of&apos; the great Appalachian coal-basin is a long narrow detached coal-field, which is, in some respects, one of the most important in the United States. This field, about 90 miles long by 2½ to 16 miles wide, extends from the southwest corner of Somerset county, Pennsylvania, through Allegany and Garrett counties, Maryland, Mineral, Grant and Tucker counties, West Virginia, into Randolph county, West Virginia. In this distance four distinct sub-districts are recognized, the Wellersburg in Pennsylvania, the Cumberland-Georges creek in Maryland, and the Elk Garden and the Upper Potomac in West Virginia. The output of coal from the whole field including steam, domestic, smithing and coking-coal of the best quality, is about 4,500,000 tons annually. It is the nearest to tide-water of all the bituminous coal-fields which supply the great coal-markets of the Northern Atlantic seaboard ;

Jan 1, 1895

By G. D. Gemmell

Effects of solid-sdutidn alloying with titanium, molybdenum, and tungsten at concentrations up to 10 pct on the strength of pure columbium at elevated temperatures (mainly 2000°F) have been investigated by means of creep-rupture, hot-tensile, and hot-hardness testing and recrystallization studies. ThIS paper presents some results from the initial part of a study of the effects of alloying on the high-temperature strength properties of columbium. The elevated-temperature strength characteristics of pure columbium were first studied. Binary alloys of columbium with titanium, molybdenum, and tungsten containing 1, 5, and 10 pct of the solute elements were chosen on the basis of their high melting points, their known solid solubility in columbium, and results of separate oxidation-resistance studies of columbium alloys. EXPERIMENTAL PROCEDURE All the materials used were of highest purity. A typical analysis of the columbium is shown in Table I. Compositions of the alloys are also given in Table I. To evaluate the strength properties of pure co-lumbium and the alloys at elevated temperatures, creep-rupture, hot-tensile, and hot-hardness testing was done on recrystallized material. To prepare the pure metal and the alloys for these tests, 1- 1b buttons were made in a water-cooled copper crucible, inert atmosphere, tungsten arc furnace. Tapered ingots, 3 in. long, were made from these buttons by a skull-casting technique and these were machined to 1/2 in. diam, swaged to 50 pct reduction (pure columbium at room temperature, alloys at lowest temperature possible without cracking, generally in range 1100" to 1800°F) and heated in vacuum (lo-&apos; mm Hg) for 16 hr at 2550°F for re-crystallization and homogenization. The resulting grain diameter was 0.1 to 0.3 mm. The 10 pct Mo alloy casting was not successfully swaged at temperatures up to 1800°F without cracking and was not included in the test program. Creep-rupture testing was done at constant load in vacuum on cylindrical specimens of 0.16 in. diam, using Instron capsules. The pressure at test temperatures was less than 10-1 mm Hg. Hardneas readings taken on the test specimen before and after testing were used as a check on possible gaseous contamination. Hot tensile tests in vacuum on cylindrical specimens of 0.125 in. diam were also made with Instron equipment at a strain rate of 0.067 min.-l. Hot-hardness measurements were taken with a unit constructed at the Du Pont Experimental Station. The test piece, supported on an alumina anvil, and the molybdenum indenter shaft with sapphire tip is heated in a platinum-wound furnace. The load applied to the pyramid indenter is measured by strain gages attached to a proving ring located outside the hot zone. In the measurements reported here the load was I kg. The tester operates in a vacuum of about 10"5 mm Hg and is capable of temperatures up to 1400°C.

Jan 1, 1960

By Rudolph G. Wuerker

THE scarcity of values of tensile strength of rocks has been explained by the lack of successful testing procedures. In the case of mine rock a description is given&apos; of the difficulties encountered in testing a cylindrical specimen, such as a core, by conventional methods. Over a period of years the following method has given definite and reproducible results with the weakest as well as with the strongest rocks. It does not completely supersede the use of cores with special fixtures but is a supplement in all cases where cores cannot be obtained, as from soft rocks, or in cases where it is less expensive to prepare test specimens by cutting them out of the rock instead of drilling cores. Principle and equipment are the same as for the test for tensile strength of hydraulic-cement mortar.&apos; The test specimen, Fig. 1, has the shape of a briquet. While in the original cement mortar test the briquet is cast in a special mold, it is prepared from rocks in different ways, depending on how easily they can be cut and shaped. Soft rocks, which cannot be core-drilled with a carboloy or diamond bit, are simply hand-cut. Only two dimensions need be watched. The first is the 1-in. diam at the narrowest cross-section of the briquet. The other critical measure is the radius of curvature of the waistline, as the roller supports in the grips have a fixed distance. This radius is ground out of the solid by means of a carborundum grinding wheel having a 3/4-in. radius. Medium hard rocks can be core-drilled with a carboloy bit. The resulting core can be used for nondestructive sonic testing first, and after that for any destructive test. By using an EX-bit and by carefully placing the coreholes, preferably by using a tenplate such as shown in Fig. 1, it is possible to obtain from the rock a punched sample from which numerous tensile briquets can be made. The outside radius of the EX-bit differs from the radius of curvature of the briquet by 1/8 in., but this still permits placing and aligning the specimen in the grips. In the case of bedded rocks the core might have bedding planes normal to the plane of the briquets, and rocks can be tested in any arrangement of the bedding planes desired. Hard rocks, limestones, igneous, and metamor-whic rocks can only be diamond-drilled or diamond-cut. Here the method of getting the tension briquets by accurate placing of EX-drill holes is especially economical. The tops of the briquets made from hard rocks cannot be rounded; they are straight cuts made with a diamond cut-off saw and rounded off on a polishing wheel. Results: As long as specimens broke over the waistline the results were considered acceptable. Further statistical treatment of the tests&apos; showed a satisfactory percentage of standard deviation. The tensile strength values obtained by this method do not represent true values because of the stress concentration caused by the curvature of the side of the piece and because of the closeness of the grips. The ratio of maximum to average stress at the plane of failure has been determined to be about 1.75." All tensile strength values listed in Table I are corrected accordingly. To avoid this stress-concentration, if there are a sufficient number of cores, tensile strength can be measured by imbedding the cores in mortar in the two outer briquets in the gangmold.4 Strain-Measurements: The applicability of the briquet specimens for strain observations was tested in the case of sandstone and shale. Two element Rosette SR-4 strain gages were used. Young&apos;s modulus and Poisson&apos;s ratio, both in tension, were computed and found to be different from those in compression, determined during the same test series and from the same rock, see Table I. References 1 L. Obert, S. L. Windes. and W. I. Duvall: Standardized Tests for Determining the Physical Properties of Mine Rock. U. S. Bur. Mines R.I. 3891 (1946). 2 Test for Tensile Strength of Hydraulic-Cement Mortar, ASTM Standard C 190-44. S F. O. Auderegg, R. Weller, and B. Fried: Tension Specimen Shape and Apparent Strength. Proc. ASTM 11939) 39, pp. 1261-1269. 4 API Code 32.

Jan 1, 1956

By P. R. Hines

Diphenyl guanidine is used as an accelerator in vulcanizing rubber. Other rubber accelerators are also flotation collectors, e.g., dithiocarbamate, thiazole, and the xanthates. Urea and its derivatives are good flotation collectors,&apos; and guanidine is the nitrogen analog of urea. These two characteristics suggested testing diphenyl guanidine as a flotation collector. Diphenyl guanidine has been tried in flotation work previously, but references give no details.&apos;.&apos; Bunker Hill Co. of Kellogg, Idaho, supplied the ore sample used in these tests. The sample was typical of the ore milled in 1949 and contained 4.52 pct Pb and 1.08 pct Zn. A flotation test made by the author with potassium ethyl xanthate as a collector, the same flotation reagents, and the same grind employed in regular Bunker Hill mill practice was the standard for comparing results with the compounds and derivatives of guanidine. The compounds and derivatives of guanidine are only fair collectors of galena. However, if potassium ethyl xanthate were used in the galena float, its presence later in the sphalerite float would make it impossible to introduce another type of collector and be certain which collector contributed the result, so the compound or derivative of guanidine under test was used in both the galena and sphalerite floats in Table I. On both the galena and the sphalerite in the Bunker Hill ore, the depressing action of sodium cyanide and zinc sulfate is much greater with collectors of the guanidine type than with the xanthates. If the depressing agents are left out when a guanidine type of collector is used, but a pH of 8.6 is maintained with either lime or sodium carbonate, the depressing action is approximately the same as in the standard xanthate test. Consequently the depressing agents, sodium cyanide and zinc, were not used in the galena floats of tests 1226, 1228, and 1286, Table I, so the galena floats would be on a comparable basis with the standard xanthate test. As shown by the tests in Table I, the loss in the tail when diphenyl guanidine is used is 8.3 to 9.3 pct, as compared to 17.6 pct with potassium ethyl xanthate, or a recovery of 2.3 to 2.0 lb more zinc. Concentrate grade is 13.7 pct with potassium ethyl xanthate and increases to 22.9 and 31.8 pct with diphenyl guanidine, showing a much higher selectivity. Unless the Barrett&apos;s No. 4 coal tar creosote is considered to be a collector, no collector other than diphenyl guanidine is present in the tests, Nos. 1226, 1228, and 1286. Tests 1218, 1253, and 1263 in Table I1 were run to check the effect of the depressing agents used in flotation of the galena (sodium cyanide and zinc sulfate) upon subsequent flotation of sphalerite by diphenyl guanidine. Urea was substituted for potassium ethyl xanthate in tests 1253 and 1263 because it is a good collector for galena and a poor one for sphalerite, and the effect of the depressing agents is more marked with urea than with potassium ethyl xanthate. Test 1205 checks the effect of urea alone without any depressing agents when used for the flotation of galena. Table I1 shows that diphenyl guanidine as a collector for sphalerite is compatible with other flotation reagents used in floating galena. When the depressing agents sodium cyanide and zinc sulfate are used in the galena flotation step, the amount of lime in the sphalerite flotation must be increased (compare 1253 and 1263). Table I11 gives some of the compounds of guanidine which were tested and compared. Some of the compounds and derivatives of guanidine* are solu- * Diphenyl guanidine is in commercial production and is available on the market. ble in water and others are not. Those tested were fed dry. When an organic collector is promising, its compounds and derivatives should be tested and their comparative collecting power recorded. Eventually, in this way, it may be possible to discover some of the essential chemical characteristics of a good collector. For example, it is interesting to compare the diphenyl and dibutyl derivatives in Table IV with those of urea in Table 111, Example 3, U. S. Patent 2,664,198. All are good collectors. Table I shows some of the effects of lime on recovery of sphalerite by diphenyl guanidine. Table V

Jan 1, 1960

By Nicholas J. Grant, Ulf Kalling, John Chipman

THE operation of a blast furnace is dependent to an important extent upon the sulphur content of materials charged and the desired limit of sulphur in the product. It has long been known that the blast furnace is the most efficient tool for desulphurization in common use and that this efficiency is associated with the strongly reducing conditions of the hearth and is enhanced by increased basicity and fluidity of the slag. The chemical reactions of desulphurization may be studied from the viewpoint of the ratio of the process or of the final equilibrium conditions. Both kinds of studies contribute to an understanding of the process and both are included here. A simple measure of the desulphurization power of a slag is given by the ratio: Pct sulphur in slag (Pet S) Pct sulphur in metal [Pct S] This ratio was used by Holbrook and Joseph&apos;,&apos; to measure relative desulphurizing powers under controlled laboratory conditions. It was also used by Hatch and Chipman3 as a measure of the equilibrium distribution. For the latter purpose it would be preferable to employ thermodynamic activities rather than percentages, but until very recently this has been impossible for lack of data. Now, thanks to the work of Morris and Williams and Morris and Buehl," the effects of carbon and silicon upon the activity of sulphur in the metal are known. The confirmation of this work and its extension to include the effects of other elements by Sherman and Chipman and by Rosenqvist and Cox&apos; make it possible to calculate the activity of sulphur in pig iron of any composition. Hence it is now possible to use data on the equilibrium distribution of sulphur to find its activity in the liquid slag and to approach an ultimate solution of the thermodynamic aspects of the problem. The rate of transfer of sulphur from metal to slag is the problem of major industrial importance and indeed the principal need for equilibrium data has been as a necessary adjunct to the kinetic studies. The rate of approach to equilibrium under laboratory conditions seems slow compared to the requirements of industrial practice, and it is clear that further laboratory studies of rates are needed. In the research reported below, the items which were investigated were the following: I—The role of mechanical stirring on the approach to equilibrium. 2—The role of MgO in desulphurization as compared to CaO. 3—The role of MnO in desulphurization. 4— The limiting reactions which constitute the slow steps in desulphurization. Experimental Procedure The experimental set-up and procedure previously described by Hatch and Chipman" were essentially followed with several small modifications. The graphite crucible containing the slag and metal charge was altered to provide considerably more active stirring and mixing of the slag and metal in the carbon monoxide atmosphere. For this purpose the crucible was machined to provide two deep cylindrical wells which were interconnected at top and bottom as shown in Fig. 1. A graphite screw with a flat thread and of shallow pitch (4 threads per in.) spinning at 600 to 800 rpm was used to lift the slag and metal over the partition between the two wells and throw them over into the second well, where the metal settled through the slag into the reservoir at the bottom. It was possible to see actual particles of slag and metal being thrown over the partition. In this respect, the stirring was more vigorous than used in the work of Hatch and Chipman. A charge of 400 g of wash metal was first melted, and 20 g of FeS was then added to yield a bath containing 1.65 pct S. Immediately 400 g of slag (as pure mixed oxides) was added and fused. The slag was generally fused in 1 hr * 10 min. Within 30 to 45 min after melting, the temperature was adjusted to 1525"C, and the first slag and metal samples were taken. The slag was picked up on the end of a cold Armco iron rod, whereas the metal was sucked into a silica tube. The wash metal composition was (in percent): 4.29 C; 0.022 S; 0.021 P; 0.38 Si. The slags used were of four fixed starting compositions covering a wide range of acid-base ratios shown in Table I. Deliberate variations in MgO were made in these slags to check the role of MgO in blast-furnace desulphurization. Changes due to additions and reactions were followed by analysis of samples. Additions of Mn and MnO were made to most of the heats to note the role of Mn and MnO on desulphurization. Three heats (62 through 64) were made in an open pot induction crucible (graphite) using a

Jan 1, 1952

By C. D. King

DURING the 30-year period spanned by these annual Howe Memorial presentations, many lecturers could proudly claim a kinship either as a student or an associate of the man whose memory we honor. Although it has been my good fortune to have attended many of these annual lectures, it was not my privilege to have known Henry Marion Howe personally. However, his great repute as teacher and scientist was known to all undergraduates of my day and the later years have enhanced my appreciation of his wisdom and foresight. Those who knew him well have said he derived particular pleasure from speculations on the future world of metallurgy. For this reason, I feel that perhaps he would not be unsympathetic to a lecture in his honor which departs from the highly instructive scientific presentations made in the past by so many able Howe Memorial lecturers, and which is concerned more with the practical phases of various steelmak-ing processes and some speculations on their future form and relative importance. The word "revolutionary" is frequently applied to each seemingly important improvement in the production of steel ingots, but in retrospect these changes, impressive as they appear at the time, are merely steps of progress. In the hundred years from the inception of tonnage steelmaking, only three processes can be truly classified as revolutionary. They are the pneumatic process, known in this country as the bessemer process; the reverberatory method called the open hearth process; and, the electric furnace process. There have been many variations and combinations of the three fundamental methods, but they remain truly the only revolutionary methods in steelmaking since its early history. Everything else has been evolutionary, in effect. doing the same things that we have done in the past but doing them better, correcting our errors through experience, and slowly but inevitably reaching a higher state of accomplishment. It has often been said that coming events cast their shadows before, and the production of steel ingots is no exception. As a result of the unrelenting demands of World War I1 and the years that followed, truly impressive progress has been made in steel ingot production. The incessant pressure for immediate results during this period required the employment of initiative and daring, as in few past decades, and many developments were brought to fruition. Of equal importance is the possible effect on future steelmaking methods of the many ideas initiated but still in formative stages. Fig. 1 portrays ingot production in the United States by the three fundamental processes over a period of 75 years and is interesting because it poses some questions as to future trends. The early ascendancy of the bessemer, its replacement in importance by the open hearth process, the amazing growth of the latter, and the recent challenge of the electric furnace are evident from the chart. Management is fully aware of these changes, but is even more interested in the future trends. Our concepts of the relative importance of the more recent developments and their possible effect on future processes may perhaps be best exemplified by a specific, hypothetical problem. Let us assume management is contemplating a new ingot producing plant with an output of 100,000 net tons per month, located in an area where some purchased scrap may be obtained but where by far the largest component will be own-produced blast furnace iron. Management requires a process or combination of processes which will yield highly uniform quality characteristics in the ingot form, and represent the soundest selection in investment and operating cost. Under these conditions, the obvious selection for the past four decades has been the open hearth process but, in view of more recent developments, management may believe that it is no longer permissible to disregard other possibilities with impunity. Accordingly, to be assured of the best possible selection, they request that you review not only the possibilities of utilizing the conventional open hearth, duplex, bessemer, and electric furnace methods, but also the more recent developments, such as the turbo-hearth, the Linz-Donawitz method, the Perrin modifications, and other possibilities. With this background, one might then appraise the relative importance of these methods to meet a specific need, and concurrently speculate on the forms that future ingot processes will assume and the relative importance of these processes.

Jan 1, 1955

By Gordon Fletcher

Pacific Rim countries currently have plans to import about 100 Mt/a (110 million tpy) of steam coal by 1990. Due to its close proximity, Powder River Basin coals offer a long term economic and dependable source of supply to the Pacific Rim. In existing boilers, Powder River Basin coals can be blended with Australian, South African, or Canadian coals. For new units, Powder River Basin coals are very competitive on a total evaluated cost basis. The advantages of using Powder River Basin coal include: assurity of supply, consistent coal quality, stable labor force, and attractive mining economics. (NOTE: PAPER NOT RECEIVED IN TIME FOR PUBLICATION.)

Jan 1, 1982

CANADA, which appears to be growing into one big mining camp, may soon be the background for another impressively large iron ore development. And again it will be Fenimore Iron Mines who will be the motivating force. Dr. J. A. Retty, Fenimore president, who was one of the important figures in the development of Labrador iron deposits, predicts a great future for property on the west coast of Ungava Bay in deep northern area of New Quebec. Fenimore properties consist of a 200 sq mile concession in addition to several hundred claims over about 112 miles along the Labrador trough, mainly in the Ungava Bay region.

Jan 5, 1953

The October meeting of the Mining and Geological Society, Lehigh University, was held in the Eckley B. Coxe Mining Laboratory, and was called to order at 8:15 p. m., by President R. L. McCann. After the reading of the minutes of the previous meeting, a short business session was held, for the purpose of electing a Vice-President to succeed G. S. Borden, who has left college. Nominees for the office were: H. J. Sloman, P. S. Justice, L. Sargeant. Dr. F. F. Hintze, of the Geology Department, was elected a member of the Advisory Committee, which now consists of the President-

Jan 12, 1916

By Fred C. Bond

SIX years have passed since the last grindability table was published.1 In that time the list has been increased with many new tests, and the development of the new Third Theory of Comminution2 has made possible the reduction of all results to a consistent work index value. In this tabulation all grindability and crushability test results are given in terms of the work index, with formulas for reversion to the older units if desired. The average values for 57 different classes of materials are listed in Table I. The total number of work index values listed is 1211, and the overall average work index is 14.42.

Jan 3, 1953

By S. Chander, V. N. Sharma

Nickeliferous laterite ore from Sukinda, Orissa (India), consists of very fine particles agglomerated into larger aggregates. The ore is chemically and mineralogically complex and presents many characterization and beneficiation problems. In this study the results of a detailed investigation to characterize the ore by several techniques are discussed. Various techniques used for characterisation include elemental analysis, electron microscopy, electronspectroscopy for chemical analysis, x-ray and electron diffraction, differential thermal and thermogravimetric analyses, EDAX analysis, Mössbauer and infrared spectroscopy. Generally one method compliments the other and it is shown that a combination of several techniques is necessary to fully characterize the ore. The scope and limitations of the techniques are also discussed.

Jan 1, 1980

By W. C. Hagel, J. H. Westbrook

THERE has been a recent revival of interest in the intermetallic compound AgMg as an experimental material for study of the physical and chemical properties of simple ordered structures. Studies of mechanical behaviors,1-4 diffusion,5,6 and thermo-dynamic properties7&apos;8 have been reported. In several of these studies, heat treatments have been carried out in argon-filled silica capsules at temperatures as high as 750°C with no apparent adverse effects. The present authors were, therefore, startled to discover in the course of some yet unpublished work, that gross melting of near-stoichio-metric AgMg compositions occurred in such samples more than 100 deg below their melting point of about 800°C. This note is to report a brief series of experiments carried out to establish the reason for this behavior. Gross errors in sample composition and failure of furnace temperature controls were quickly eliminated as causes of melting. The first tangible lead came from chemical analysis of an AgMg sample which had melted during treatment at 750°C. A silicon content of 3.3 wt pct was found. Since satisfactory analyses had been obtained on the original as-cast ingot, contamination by diffusion and/or reaction with the fused silica capsule seemed a distinct possibility. A perplexing fact, however, was the apparently capricious incidence of the effect. Not only was it previously unknown, even in the experience of the present authors; but, in the early part of the present study, melting sometimes occurred and sometimes not with specimens treated under constant conditions. Indeed, one sample successfully survived a 750°C heat treatment and yet melted completely during the course of a subsequent anneal in an identical capsule at a lower temperature. To obtain evidence that silicon contamination could lower the melting point to the extent observed, the following experiment was performed. A series of ternary alloys was made up with a stoichiometric AgMg base and containing 0.1, 0.2, 0.4, 1, 2, and 4 wt pct Si. Melting was done in MgO crucibles under a cover of argon gas. After holding 10 to 20 min in the temperature range 850° to 900°C, the alloys were allowed to solidify in the crucible and the temperature during cooling automatically recorded with a Pt/Pt-10 Rh thermocouple. Results from the cooling curves are shown in Fig. 1. Checks within 2 to 5C° were obtained upon repeated melting, cooling, and freezing. The whole series of cooling curves as well as metallographic examination of the melted alloys established that the AgMg rich portion of the AgMg-Si quasibinary is an eutectic-type system. The melting point of AgMg is lowered from approximately 820°C in the pure stoichiometric binary9 to about 710°C in the saturated intermetallic phase. Since second phase was observed in all samples on cooling to room temperature, the solid solubility of AgMg for silicon evidently falls rapidly with decreasing temperature as indicated schematically by the dashed solvus in Fig. 1. It is thus established that a silicon content

Jan 1, 1963