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By Charles H. Jacoby

In 1774 a Swedish chemist, C. W. Schule, first recognized manganese as an element. That same year Schule's associate, J. G. Gahn, isolated the element manganese for the first time. In 1856 the Bessemer process of steelmaking gave birth to the economic importance of manganese. Later, in 1882, Robert Hadfield discovered high manganese steels. Although the primary use of manganese is in the ferroalloy industry, two additional important uses for manganese are making chemicals and dry cell batteries. Manganese is also vital to plant and animal life. Various chemical compounds of manganese are used in fertilizers, feeds, glass manufacture, paints, varnishes, and for numerous medicinal and chemical purposes. For the study of industrial minerals and rocks, only the chemical and battery grade material is of concern, but for the sake of comparison, metallurgical aspects are included in this presentation. Although currently the world's largest consumer of manganese, the United States is producing only minor amounts of ore at the present time. This is due primarily to the fact that although huge deposits of manganese occur within our borders, all are of such low grade as to be economically unfeasible to mine. For many years various government agencies and segments of private industry have devoted sizable sums of money and time in an attempt to upgrade ores from the various deposits, and also in an attempt to recover manganese from blast furnace slags. In view of current world prices, and the quantity of high grade material available, there is little likelihood that any of these approaches will be found to be economically feasible in the near future. Geology and Mineralogy Mineralogy There are over one hundred minerals that contain manganese. These minerals vary from those with compositions that are predominantly manganese to those having only minor percentages. [ ] Geology From a geological standpoint most manga¬nese deposits are complex. In general, it can be said that all primary deposits of manganese are carbonates or silicates. The most productive and profitable have been those of sedimentary origin and residual concentrations. Examples of these residual types of deposits are associated with the metamorphosed lodes of Madhya, Pradesh, India, and the lateritic deposits of Orissa and Bihar, India; nodules in the residual clays of the Philippine Islands, U.S. southern Appalachians and Arkansas, Ghana, and Brazil. Sedimentary manganese deposits are best exemplified by the Nikopol district of Russia and the Tchiatouri area of Georgia, USSR. Hydrothermal replacements are characterized by the rhodochrosite deposits of Butte and Phillipsburg, Mont. In general, the hydrothermal type deposit has not resulted in any large tonnages being produced, but may have given

Jan 1, 1975

By Keith Leonard Sutherland

THIS paper is a study of the differential flotation of the sulphide minerals in the presence of salts of silver, lead and zinc. In practice, accidental activation due to these salts is more important than their use as reagents to replace copper sulphate. The general method of investigation has been based upon contact tests, the temperature of 35°C. being chosen in conformity with earlier work. Potassium ethyl xanthate and potassium amyl xanthate were selected as collectors and pure sulphide minerals were used. The experimental procedure has been outlined in earlier papers and all solutions were kept carbonate-free.'' Contact, or spreading of an air bubble, at a mineral surface indicates the presence of an adsorbed collector film. PURITY OF REAGENTS The xanthates were purified in the usual manner.1 Neither the cyanide nor the sodium hydroxide solutions contained sufficient carbonate to give a precipitate with barium chloride solution. The silver sulphate was prepared from pure silver nitrate by evaporation with concentrated sulphuric acid until there was no evidence of brown fumes. This solution was diluted and the difficultly soluble sulphate washed with water so that unchanged nitrate was dissolved. The resultant crystal-line powder was pure white. The lead and zinc salts were prepared by dissolving especially pure lead and zinc in C.P. nitric and sulphuric acid solution and the crystals drained. The standard solutions were checked by titration. It was felt desirable to use the sulphate radical wherever possible, but since lead sulphate was insufficiently soluble for the purpose of the experiments, it was necessary to use some other lead salt. A.R. copper sulphate was used without further purification. RESULTS The results are presented in the accompanying figures; the areas of noncontact (nonflotation) are shaded in Figs. 8, 9, 10 and 11; in the remainder they lie to the right of the curve. Zinc Sulphate The curves in Fig. I are to be compared with those for Fig. 2, for which zinc sulphate is absent. This comparison shows that the influence of the zinc ion is usually small. Its influence is more marked, however, for chalcopyrite in the absence of cyanide. The influence of zinc sulphate is also marked for copper-activated sphalerite, for which tests were made only in the absence of cyanide. The results are of importance in the separation of pyrite from copper-activated sphalerite when zinc sulphate is added in the lead flotation section (p. 204 of ref. I). Sphalerite does not adsorb the collector (i.e., become floatable) under the conditions chosen.

Jan 1, 1942

By W. C. Hagel

Previous inuestigators have repovted unusually low H* and Do values for self-dzf@szon in certazn bcc metals, e.g., chromium nnd y -uvanium. It has been postulated that this is nn experimental crl -tetion for the existpnce of a four -atom ring meclzanzsm, mid there could be. zmpovtant theoretrcal Implicatlons. By utilizing a precise sectioning technique with Cr51 as the tracer, self-dzffi-lsion measurements in large grains of 99.99-pct Cr were extended from 1200° fo 1600"C. A least- squares analysis of the data yields that D 0.280 exp (-73,20U/RT) cm2 sec-'. These AH* and Do unlues are not anomalous; there is little reason to believe that n vacancy mechanism is not opevatiue. Apparent differences at lower temperatures may result from preferential diffusion along short-circuititing paths and/or sample contamination. WITH continued technological effort, chromium and chromium-base alloys should ultimately become useful high-temperature structural materials. Accurate measurements of self-diffusion coefficients in the pure metal are necessary for a quantitative understanding of sintering, grain growth, creep, and other related rate processes. However, two conflicting determinations have been reported.* Using an Since careful diffusion studies normally yield Do values ranging from 0.1 to 10 cm2 sec-l, the Paxton-Gondolf results require independent experimental corroboration before an undue amount of speculation arises to explain the apparent anomaly. As discussed by Nowick6 and clearly shown by Hoffman and Turn-bull7 for self-diffusion in silver, a low AH* and Do can arise from preferential diffusion along grain boundaries or other short-circuiting paths. The most reliable data come from high-temperature measurements where volume effects predominate. Following a precise sectioning technique developed for determining silver diffusion in the intermetallic compound AgMg8 and cation diffusion in the corundum oxide Cr2O3,9 the purpose of this study was to measure true volume diffusion in high-purity, large-grain samples at higher temperatures than considered previously. Another point of interest is the frequent proposal10-12 that chromium undergoes an allotropic transformation between 1375" and 1800°C where the diffusion data might then show a discontinuity. I EXPERIMENTAL 1) Sample Preparation. The highest purity (99.997 pet) Cr currently available is produced by reduction of chromium tri-iodide. Three pounds of the resulting crystal bar were shipped in a sealed container with a complete chemical analysis from the vendor.* In conformity with the procedure used for

Jan 1, 1962

By Carl F. Floe, Michael B. Bever

TRE solubility of hydrogen in molten copper-tin alloys is of both practical and theoretical interest. From a practical standpoint, data on the equilibrium solubility as a function of temperature, pressure and alloy composition are valuable for a better understanding of porosity problems in bronze castings. From the theoretical point of view the determination of the hydrogen-copper-tin equilibrium is of interest since it extends the laws governing the solution of gases in metals. This paper presents the results of an investigation of the solubility of hydrogen in representative compositions of the copper-tin system at temperatures ranging from above the liquidus to 1300°C. and at pressures from less than 50 mm. of mercury to about atmospheric. REVIEW OF PREVIOUS WORK The solubility of hydrogen in copper was determined by Sieverts and Krumbhaarl in 1910 and by Roentgen and Moeller2 in 1934. Their values are in fair agreement. In 1926 Iwasé3 reported results that were very much higher. The published data on the solubility of hydrogen in tin do not agree. Smithells4 states that no reliable data are available. According to Sieverts and Krumbhaar,5 hydrogen is insoluble in tin. Bircumshaw,6 on the other hand, found a definite solubility at 800°C. The latter's experimental procedure did not provide for stirring of the metal and in his opinion he failed to reach equilibrium. Iwasé3 again reported large solubility values. For copper alloys, Sieverts and Krumbhaar6 distinguished between alloying elements that do not markedly affect the solubility of hydrogen, elements that increase the solubility, and elements that reduce it. They named gold, tin, and aluminum as examples of this last group and reported hydrogen solubility data at 1225°C. for the copper-rich side of these alloy systems at atmospheric pressure. Without giving experimental results, they stated that the amount of hydrogen dissolved by liquid copper alloys is proportional to the square root of the pressure as in pure metals. These authors suggested that in a limited way the effect of an alloying element on the solubility of a gas is related to the constitution diagram for the alloy system. Sieverts7 also called attention to the fact that the curve of hydrogen solubility versus composition of copper-tin alloys shows a sharp change of direction at the composition of Cu3Sn and suggested that this compound persists at least to some extent in the molten state. Iwas3é reported large hydrogen solubility values for several compositions of copper- tin alloys, which appear to be in error.

Jan 1, 1944

By Leonard B. Gulbransen, John R. Lewis, W. Martin Fassell, J. Hugh Hamilton

A simple reproducible method was developed for determining the ignition temperatures of magnesium and magnesium alloys and by this method magnesium and over 100 magnesium alloys were measured. The ignition temperature of magnesium was determined in O2-SO2, O2-N2 mixtures and in O2 from 0.166 to 10 atm pressure. The ignition temperature of magnesium is generally lowered by alloying and increased by an increase in oxygen pressure. WITH the expanded use of magnesium alloys in industry, ignition temperatures are of considerable importance, especially in heat treating and for service at elevated temperatures. Magnesium alloys exhibit a relatively slow linear oxidation rate up to temperatures near the melting point.' At some critical temperature the rate of oxidation becomes extremely rapid. This high rate of oxidation is accompanied by the emission of light and additional characteristics suggesting a flame. The literature concerning the ignition temperatures of magnesium and magnesium alloys is relatively incomplete and the values reported by various authors are not in agreement. The most probable reasons for this are: 1—The absence of a suitable definition of ignition, and 2—the need of a standardized method of determining the ignition temperatures of inflammable metals and alloys. The exact date of the discovery of the fact that magnesium will ignite and burn is unknown. It is likely that H. Davey encountered this property of the metal during its preparation in 1808. The first reference in the literature specifically on ignition of magnesium is by Lenze, Metz, and Rubens.' They investigated the inflammability of certain magnesium alloys. Brown3-' reported that magnesium ribbon will ignite in air at 507 °C by what was called the rising temperature method. Hartman, Nagy, and Brown" reported that magnesium powder ignites from 475" to 560°C depending on particle size. According to Guise, Mars, and Wilson prolonged heating in air at 427°C of common casting magnesium alloy causes it to ignite. Samples of magnesium alloys were placed directly in the flame of a torch by Carapella and Shaw.' These investigators obtained some evidence of melting prior to ignition. For commercial magnesium, they reported an ignition temperature of 650°C. Their values varied from 450" to 800°C for magnesium alloys. Willmore and Peterson" studied the effect of air velocity, humidity, rate of heating, and foreign metal contact on the ignition temperature of magnesium. They conclude that melting is not a prerequisite for ignition and that the conditions which influence ignition are complex and difficult to analyze. The only quantitative theoretical treatment of the ignition temperatures of magnesium and magnesium

Jan 1, 1952

By F. Kurata, P. C. Davis, T. L. Gore

An experimental method and apparatus for the study of the low-temperature phase and volumetric behavior of volatile mixtures are described. The phase diagrams, including the critical points, and the volumetric behavior of a natural gas and a mixture of the natural gas with methane at temperatures from -40°F to -200°F and pressures to 1.200 11si are givrn. INTRODUCTION Knowledge of the phase and volumetric behavior of mixtures of the light hydrocarbons at low temperatures is becoming increasingly important as interest in low-temperature separation processes increases. Distillation at low-lemperatures has been used for some time to recover ethane and ethylene from natural gas and refinery gas for petrochemical uses. Removal of excess nitrogen from natural gas by distillation has been proposed as a means of increasing the capacity of gas transmission lines and of improving the marketability of the gas.1,2 Evaluation of the latter process has been hampered, however, by the scarcity of data from which the phase behavior of natural gases at low temperatures might be predicted. While existing correlations of vaporization equilibrium constants may be used to predict the behavior of such mixtures at lower pressures, high-pressure computations often require knowledge of the location of the critical point of the system involved. Although correlations have been developed for the prediction of the critical temperature and pressure of certain types of hydrocar-bon systems, they do not apply to very volatile systems such as nitrogen-bear-ing natural gases. This paper describes the initial stages of an investigation of the low-temperature behavior of a numher of natural gases and other gases of commercial interest. The experimental method and apparatus are described. and the phase and volumetric behavior of a natural gas and a mixture of the natural gas with methane are presented. PREVIOUS WORK The published low-temperature vapor-liquid equilibrium data for hydrocarbons and mixtures of hydrocarbons with nitrogen and helium are listed in Table I. Most of these data are for binary systems, and the data of Stutz-man and Brown" at 100 psi are the only data on a natural gas. The data of Bloomer and Parent3 on the methafie-nitrogen system, which have been phblished since this study was completed, are a valuable addition to the knowledge in this field. Prior to the publication of these data the only published critical point data on systems having critical temperatures below the ice point were those of Ruhemann.1 on the methane-

Jan 1, 1952

By Keith Leonard Sutherland

THIS paper is a study of the differential flotation of the sulphide minerals in the presence of salts of silver, lead and zinc. In practice, accidental activation due to these salts is more important than their use as reagents to replace copper sulphate. The general method of investigation has been based upon contact tests, the temperature of 35°C. being chosen in conformity with earlier work. Potassium ethyl xanthate and potassium amyl xanthate were selected as collectors and pure sulphide minerals were used. The experimental procedure has been outlined in earlier papers and all solutions were kept carbonate -free.1,4 Contact, or spreading of an air bubble, at a mineral surface indicates the presence of an adsorbed collector film. PURITY OF REAGENTS The xanthates were purified in the usual manner.1 Neither the cyanide nor the sodium hydroxide solutions contained sufficient carbonate to give a precipitate with barium chloride solution. The silver sulphate was prepared from pure silver nitrate by evaporation with concentrated sulphuric acid until there was no evidence of brown fumes. This solution was diluted and the difficultly soluble sulphate washed with water so that unchanged nitrate was dissolved. The resultant crystalline powder was pure white. The lead and zinc salts were prepared by dissolving especially pure lead and zinc in C.P. nitric and sulphuric acid solution and the crystals drained. The standard solutions were checked by titration. It was felt desirable to use the sulphate radical wherever possible, but since lead sulphate was insufficiently soluble for the purpose of the experiments, it was necessary to use some other lead salt. A.R. copper sulphate was used without further purification. RESULTS The results are presented in the accompanying figures; the areas of noncontact (nonflotation) are shaded in Figs. 8, 9, 10 and 11; in the remainder they lie to the right of the curve. Zinc Sulphate The curves in Fig. I are to be compared with those for Fig. 2, for which zinc sulphate is absent. This comparison shows that the influence of the zinc ion is usually small. Its influence is more marked, however, for chalcopyrite in the absence of cyanide. The influence of zinc sulphate is also marked for copper-activated sphalerite, for which tests were made only in the absence of cyanide. The results are of importance in the separation of pyrite from copper-activated sphalerite when, zinc sulphate is added in the lead flotation section (p. 204 of ref. I). Sphalerite does not adsorb the collector (i.e., become floatable) under the conditions chosen.

Jan 1, 1942

By J. Gordon Parr, D. H. Polonis

High purity alloys of titanium and iron, made by a technique of levitation melting, have been investigated with particular reference to martensite formation and decomposition in the hypoeutectoid range. A preliminary study has been made of the occurrence of the phase corresponding to the structure Ti2Fe. MANY of the previous investigations of Fe-Ti alloys have been made using Kroll sponge as a source of titanium; and the subsequent heat treatments to which alloys have been subjected has, on occasion, led to further contamination. Worrier,',' who suggested a part of the equilibrium diagram for the binary system, and Wallbaum and coworkers,3-5 who worked largely with iron-rich alloys, all used Kroll sponge. Van Thyne, Kessler, and Hansen,6 in their determination of the equilibrium diagram, used iodide titanium for alloys up to 30 pct Fe. Duwez,7 who measured the M. temperature of titanium binary alloys with many solute elements, used iodide titanium in all cases except in his work on Ti-Fe alloys for which he used Kroll sponge. The investigation of the supposed phase Ti2Fe by Rostoker8 nvolved the use of iodide titanium. A section of the constitutional diagram, after Van Thyne et al., is reproduced in Fig. 1. Frequently too much stress is placed on the effect of contaminants in equilibrium and nonequilibrium systems, but there is no doubt that titanium alloys are extremely susceptible to interstitial atoms. Consequently, the main purpose of the work to be described was to determine those features of phase transformations in pure Ti-Fe alloys that were considered of importance in commercial heat treatments. For, although commercial alloys may not be of high purity, the investigation of a system uncomplicated by traces of impurity is a desirable starting point. Another incidental feature, the occurrence of Ti2Fe, was also investigated. The entire study was carried out using powders obtained from alloy ingots, for diffusion reactions are often more rapid in small particles than in bulk specimens. The frequently adopted practice of ascertaining phase constitutions by X-ray analysis of powders, and relating these to the microstructures and mechanical properties of bulk specimens, is considered by the authors to be open to criticism. In the martensite reactions in the Fe-Mn system, for example, it has been shown- hat similar phase distributions in solid and powder may result in different hardness values and appearance under the microscope; and it is possible that similar anomalies might occur in the Ti-Fe system. Consequently, in order to

Jan 1, 1955

By W. E. Rice

The ceramic industry has to do with forming or molding articles of clay, and imparting to them their characteristic properties of permanence, strength and color by subjecting them to heat treatment in kilns. This heat treatment is commonly known as "firing" or "burning." The art of firing clay ware antedates the industrial use of coal; hence wood was the fuel first used, and the earliest kilns were built to burn wood. The majority of the clay ware produced today is fired in periodic kilns that are essentially enlarged structures similar to the earliest enclosed kilns; a kiln consists of a large chamber 16 to 32 ft. dia. (or rectangular) in which the ware is charged and fired either in direct contact with flame or hot gases from the fuel, or in saggers which shield the ware from direct contact with the gases. The fuel is burned in a number of small furnaces built in the thick wall that encloses the chamber; these furnaces are from 16 to 36 in. wide and from 3 to 5 ft. long; some of them have horizontal or sloping grates, but many have no grates; the last are called "dead-bottom" furnaces. The temperature necessary to mature the charge in the kiln varies for different clays; for some it is as low as 1800°, and for others as high as 2700" F. Wood was an ideal fuel for the low temperatures that were used in early kilns; it burns freely and produces a long, clean flame, which promotes uniform distribution of the heat in the kiln; it does not coke and so restrict the passage of air through the fuel bed; the ash does not melt in the fuel bed to form clinker; and the ash that is carried into the chamber and deposited on the charge does not contain iron and sulfur to discolor the clay. The extent of the ceramic industry now precludes the general use of wood in kilns, so that today this industry is one of the large users of bituminous coal, burning more than eight million tons annually in kilns. Manufacturing plants usually are at or near the source of clay, with deposits of coal suitable for kilns occurring near the clay. The cost of coal is the largest single item of expense in the manufacture of clay ware, and, because all coals are not equally suitable for the process, the careful selection of coal is important. In this selection the desidera-

Jan 1, 1932

By J. W. Marx, R. H. Langenheim

The authors are to he complimented for a timely presentation of useful information concerning application of heat to oil reservoirs to increase the rate and ultimate recovery of oil. The solution for heated area resulting from constant rate injection of a hot fluid, presented by the authors, and the fluid-flow analogy, solved by Carter,' are particularly interesting in that 110 restriction is placed on the direction of development of the heated area. It is not necessary that the heated area grow radially. Thus the solution could provide useful information for heat injection in any type of well pattern with any specified swept area data. However, it was assumed in the development that the heated region would remain at a constant clevatcd temperature. Vertical heat losses were computed on this basis. Physically. the assumption that the heated region will remain at a constant temperature (independent of distance from the injection point) appears to require that the heat injection medium be stcam, or other condensible gases near the boding point at injection pressure. If a hot liquid below the boiling point or a hot gas considerably above saturation temperature were used, the temperature of the heated region would decrease with distance from the injection well. Lauwerier2 has discussed this problem for a linear system. (See also Jenkins and Aronolsky; and McNiel and Nelson.') Thus, the authors' solution applies more nearly to steam injection than to hot water injection or hot, non-condensable gas injection. Assuming steam as the injection medium, it appears that steam would pass through the constant-temperature heated region and condense upon contact with the unheated sand. The tempcrature in the condensing region would probably be governed by the release of heat of vaporization required for phase equilibrium at the existing pressure distribution. Temperatures in the region would also be influenced by vaporization of hydrocarbon. Thus, it is doubtful that an expression for radial temperature distribution based on heat conduction only (such as the authors' Eq. 9) would have practical significance. As pointed out by Marx and Langenheim, the growth of the heated area under constant rate steam drive will eventually be limited economically by vertical heat loss. The possibility of continuing to move heat economically by cold water injection or by increasing the steam injection rate appears to be a very important consideration. (Movement of liquids away from the injection well should increase injectivity.) Fortunately, the solution presented by the authors may be generalized to thc case of a variable heat injection rate. The general solution is:

By Keith Leonard Sutherland

This paper is a study of the differential flotation of the sulphide minerals in the presence of salts of silver, lead and zinc. In practice, accidental activation due to these salts is more important than their use as reagents to replace copper sulphate. The general method of investigation has been based upon contact tests, the temperature of 35°C being chosen in conformity with earlier work. Potassium ethyl xanthate and potassium amyl xanthate were selected as collectors and pure sulphide minerals were used. The experimental procedure has been outlined in earlier papers and all solutions were kept carbonate-free.14 Contact, or spreading of an air bubble, at a mineral surface indicates the presence of an adsorbed collector film. Purity of Reagents The xanthates were purified in the usual manner.' Neither the cyanide nor the sodium hydroxide solutions contained sufficient carbonate to give a precipitate with barium chloride solution. The silver sulphate was prepared from pure silver nitrate by evaporation with concentrated sulphuric acid until there was no evidence of brown fumes, This solution was diluted and the difficultly soluble sulphate washed with water so that unchanged nitrate was dissolved. The resultant crystalline powder was pure white. The lead and zinc salts were prepared by dissolving especially pure lead and zinc in C.P. nitric and sulphuric acid solution and the crystals drained. The standard solutions were checked by titration. It was felt desirable to use the sulphate radical wherever possible, but since lead sulphate was insufficiently soluble for the purpose of the experiments, it was necessary to use some other lead salt. A.R. copper sulphate was used without further purification. Results The results are presented in the accompanying figures; the areas of noncontact (nonflotation) are shaded in Figs. 8, 9, 10 and 11; in the remainder they lie to the right of the curve. Zinc Sulphate The curves in Fig. I are to be compared with those for Fig. 2, for which zinc sulphate is absent. This comparison shows that the influence of the zinc ion is usually small. Its influence is more marked, however, for chalcopyrite in the absence of cyanide. The influence of zinc sulphate is also marked for copper-activated sphalerite, for which tests were made only in the "absence of cyanide. The results are of importance in the separation of pyrite from copper-activated sphalerite when zinc sulphate is added in the lead flotation section (p. 204 of ref. I). Sphalerite does not adsorb the collector (i.e., become floatable) under the conditions chosen.

Jan 1, 1943

By Edward Wisser

The environment of an ore body is taken to mean not only its physical surroundings but every factor, passive or active, that conditioned the ore shoot, saving only the original composition of the solutions that formed the shoot. Collection of data related to the shape and characteristics of veins should be followed by correlation of the data and the formulation of generalizations regarding ore formation. The nature of the criteria used in arriving at these generalizations is discussed. Certain of the criteria, when used with an understanding of their underlying causes, become "ore-guides." In the course of his study the geologist must not confine himself to the immediate surroundings of the veins, but should attempt to work out the geologic history of events culminating in the crucial epoch for any mining district, the period of mineralization. The work may involve study of features far removed from the veins and related to them only indirectly. It commonly means thorough study of the geology of the entire region surrounding the ore deposits. The following question has been suggested for discussion: "Are there any criteria by which one can determine when mining operations have reached the roots of an ore deposit?" The question deals less with the roots of a particular ore body than with the lower limit of the vertical range within which ore bodies may be expected. It concerns a critical line upon the longitudinal vertical projection of a vein.† Below this line it is useless to look for ore shoots; above the line exploration below the bottoms of individual ore shoots may be justified. Can we learn to determine the position of such a line? In some multivein districts the line for any given vein may be approximated by simple interpolation or extrapolation. Where this is possiblc the bottoms of the lowest ore shoots in the various veins are points on an imaginary, gently rolling surface. The trace of this surface upon the vein is our critical line for that vein. The imaginary surface rolls so gently that it may be projected from two or more known veins to an unexplored vein near by. Here is a criterion for the bottoming of ore that has nothing to do with changes in the appearance of the vein in question; it rests solely on the depth at which the ore bottomed in adjacent veins. The method is not applicable in districts only slightly explored in depth, nor where the lower limit of the ore-bearing horizons

Jan 1, 1941

By John S. Brown

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

Jan 1, 1941

By C. S. Barrett, P. Coheur

AXnealing twins are common in the microstructure of copper that has been rolled and recrystallized. In such samples it follows that a twin relationship should exist between components of the re-crystallization texture,' and several examples of this have been reported. For example, twin relationships have been found in recrystallized electrolytic copper sheet, as indicated in Fig. I, from a paper by Coheur and Lejeune.2 In this pole figure the cube texture (100) [001] is indicated by the hollow squares in the lower half of the figure (the pole figure for 200 reflections) and in the upper, (III), part of the figure. The texture contains, in addition to this orientation, the first-order twins of it, shown in the figure by the filled triangles. This orientation relation has been suggested by others also, under certain annealing conditions,3'4 although pole figures have not been published to confirm it. Some orientations in recrystallized sheets are identical with their twins, because of the symmetry elements of the texture— this is true, for example, with the (113) [ZII] texture so commonly reported for brass—hence it appears impossible in such samples to decide whether the twin relationships result from twinning or merely from the symmetry of the deformation process. The present investigation of a commercial copper strip seems to yield an example in which annealing twins account unambiguously for the principal orientations present. It proves to be a case, also, for which the recrystallization texture cannot be viewed as derived from the deformation texture by a first or second-order twinning mechanism. Materials and Methods The samples investigated were of secondary copper (melted in belgium) to which 0.19 per cent iron had been added to raise the recrystallization temperature. How much the orientation characteristics of this metal can be ascribed to the iron content and how much to other impurities or to melting and pouring practice have not been investigated.* The rolling was done in one direction only, on a mill with rolls of about 20-cm diameter. A strip I. cm wide was reduced from 5 mm thickness to 0.05 mm by several cold passes at commercial speeds. The samples cut from this 99 per cent reduced strip were X-rayed throughout their entire thickness. A pole figure made soon after rolling and annealing was identical, within experimental error, with one that was made when a two-year interval occurred between rolling and annealing. X-ray patterns were made on a camera2 that traversed

Jan 1, 1947

By G. Gutzeit

An inner complex is a cyclic chemical structure containing an inorganic cation that is bound simultaneously to several atoms in a single organic molecule; on the one hand by means of ordinary valence bonds (electron exchange), on the other hand through the action of the electric field thus created, which satisfies the so-called secondary valences. The relative positions of the salt-forming and complex-forming groups are such that most frequently a four, five, or six-membered ring results through this double attachment of the cation.1-6 The formation of inner-complex ring systems depends not only upon the nature and suitable position of the salt-forming and complex-forming groups for ring closure, but, to a great extent, also on the nature of the metallic cation entering the reaction. This selective character of chelate-forming organic compounds is one of their most interesting and most valuable properties. As a matter of fact, the largest number of their practical applications is based upon their specificity.4,7-l3 Once a chelate compound is formed, its character is definitely "organic" in nature. In other words, its properties are conditioned to a much larger degree by the carbon chains or rings than by the metallic atom. Many inner complexes are soluble in nonpolar solvents such as benzene, paraffin oil or carbon tetrachloride, while the chelate-forming reagent before closure of the metal-organic ring is water soluble. (Example: copper complex of salicyl-aldoxime') It is obvious that such particular properties as those indicated above can be utilized whenever specificity and practically complete binding of inorganic ions into an undissociable complex are required. One of the well-known applications of chelate-forming compounds has been the development of specific reagents in analytical chemistry, creation of the spot-test method,4,14-16 and the application of the same principles to the contact print method for determining minerals." Chelate-forming Compounds as Collectors In the field of flotation, where selectivity is often a quality of paramount importance for the collector, various workers have lately attempted to apply their knowledge of specific organic analytical reagents to this purpose. A. C. Vivian18 has concentrated cassiterite by using ammonium nitrosophenylhydroxyl-amine (Cupferron) C6H5NO(=NONH4). Holmanl9 has tested dimethylglyoxime for the flotation of nickel oxide minerals, while deWitt has shown in a series of systematic experiments that alpha-diox-imes were generally selective collectors for nickel ores. Taurin NH2(CH2)2S03H has been proposed for the concentration Of Oxidized lead ores.19 Diphenylthio-carbazone

Jan 1, 1947

By M. Schussler, J. S. Brunhouse

Arc-melted and electron-beam melted tantalum in the cold-worked and the recrystallized conditions showed high strength, good tensile ductility, and excellent notch toughness down to 321°F. Arc-melted material, containing moderate amounts of interstitials, possessed better short-time strength than higher purity electron-beam melted material up to 2000°F. Cold-working substantially strengthened arc-melted tantalum, whereas electron-beam melted material exhibited a low work-hardening rate and possessed better formability characteristics. With identical compositions and microstructures, the mechanical properties of melted tantalum and uacuum-sintered tantalum should be similar. TANTALUM metal usage is increasing rapidly in a number of applications. The outstanding chemical corrosion resistance of tantalum accounts for its applications in chemical processing equipment for severe service conditions and for surgical uses in the medical field. The largest present requirements for tantalum are in the electronics industry, where its special properties are useful in capacitors. The high melting point (5425°F) and inherent ductility of tantalum also suggest that tantalum and tantalum-base alloys might offer an excellent combination of high strength at very high temperatures and good fabri-cability. Pure tantalum has been used in significant amounts in parts requiring high-temperature strength, such as heating elements, reflectors, and heat shields in high-vacuum high-temperature furnaces and in electronic tubes. A few very promising tantalum-base alloys have been developed and are being investigated extensively. The possibilities for tantalum as a high-temperature structural material, either unalloyed or alloyed, will become better defined when more extensive mechanical property data are known. pughl measured the tensile properties of vacuum-sintered tantalum in sheet form for the temperature range of 78" to 1500°K (-321' to 2240°F), and Bechtold reported data obtained at low temperatures.' Drennen3 determined creep and stress-rupture properties of both vacuum-sintered and arc-melted tantalum sheet at 1200 °F. Some additional data on the mechanical properties of tantalum at temperatures up to 5000 °F have been summarized elsewhere.4'5 It is probable that large structural shapes of tantalum, either unalloyed or alloyed, can most readily be produced from ingots prepared by melting. Consequently, the present investigation was undertaken to determine more extensive short-time mechanical properties of tantalum metal consolidated by melting. EXPERIMENTAL PROCEDURE Melting and Fabrication—Two tantalum ingots were utilized in this study to obtain information on the effect of interstitial elements on mechanical properties. Both ingots were melted from Union Carbide Metals Co. tantalum dendrites.

Jan 1, 1961

By G. Gutzeit

METAL-ORGANIC INNER COMPLEXES AN inner complex is a cyclic chemical structure containing an inorganic cation that is bound simultaneously to several atoms in a single organic molecule; on the one hand by means of ordinary valence bonds (electron exchange), on the other hand through the action of the electric field thus created, which satisfies the so-called secondary valences. The relative positions of the salt-forming and complex-forming groups are such that most frequently a four, five, or six-membered ring results through this double attachment of the cation.1-6 The formation of inner-complex ring systems depends not only upon the nature and suitable position of the salt-forming and complex-forming groups for ring closure, but, to a great extent, also on the nature of the metallic cation entering the reaction. This selective character of chelate-forming organic compounds is one of their most interesting and most valuable properties. As a matter of fact, the largest number of their practical applications is based upon their specificity. 4,1-13 Once a chelate compound is formed, its character is definitely "organic" in nature. In other words, its properties are conditioned to a much larger degree by the carbon chains or rings than by the metallic atom. Many inner complexes are soluble in nonpolar solvents such as benzene, paraffin oil or carbon tetrachloride, while the chelate-forming reagent before closure of the metal-organic ring is water soluble. (Example: copper complex of salicyl-aldoxime.) It is obvious that such particular properties as those indicated above can be utilized whenever specificity and practically complete binding of inorganic ions into an undissociable complex are required. One of the well-known applications of chelate-forming compounds has been the development of specific reagents in analytical chemistry,, creation of the spot-test method,4,14-16 and the application of the same principles to the contact print method for determining minerals.17 CHELATE-FORMING COMPOUNDS AS COLLECTORS In the field of flotation, where selectivity is often a quality of paramount importance for the collector, various workers have lately attempted to apply their knowledge of specific organic analytical reagents to this purpose. A. C. Vivian18 has concentrated cassiterite by using ammonium nitrosophenylhydroxylamine (Cupferron) C6H5NO(=NONH4). Holman19 has tested dimethylglyoxime for the flotation of nickel oxide minerals, while deWitt has shown in a series of systematic experiments that alpha-dioximes were generally selective collectors for nickel ores. Taurin NH2(CH2)2SO3H has been proposed for the concentration of oxidized lead ores.19 Diphenylthiocarbazone

Jan 1, 1946

By B. N. Das, J. B. Darby, P. A. Beck, Y. Shimomura

A POWDER pattern for the (Cr, Mo, Co)R-phase annealed at 1200°C was reported in 1951.1 Through the courtesy of Prof. D. P. Shoemaker of Massachusetts Institute of Technology the authors became aware of inconsistencies of this pattern with that to be expected from the structure of the R-phase, as determined by Komura, Shoemaker, and Shoemaker.' In addition, Professor Shoemaker also noted that the powder pattern reported8 for the (Cr, Mo, Co)D-phase, annealed at 1300°C, agreed fairly well with that to be expected from the newly determined structure of the R-phase. In view of these findings, the previously reported powder patterns of the R-phase and of the D-phase were compared carefully. It was found that most lines in the two patterns (22 lines) were to a fair degree of accuracy related to each other by a single conversion ratio for the corresponding d spacings. The value of the conversion ratio was found to be 1.0058, so that the d spacings of the D-phase pattern previously reported were larger than the correspond- ing d spacings for the reported R-phase pattern by approximately that factor. The intensity relationships between corresponding lines in the two patterns were similar, as judged visually. The following exceptions were noted: Lines Nos. 2, 3, 19, 20, 21, 22, 23, 24 and 25 of the D-phase pattern,:' all designated weak or very weak, were missing in the apparently somewhat fainter R-phase pattern used.' Lines 1, 2, 3, 5, 15 and 34 (all weak or very weak), reported for the R-phase, were missing in the D-phase pattern, Table I. In view of these observations it seemed probable that the two patterns differed from each other mainly by a slight change in lattice parameters (with c/a remaining approximately constant), and that the pattern previously reported for the R-phase contained some weak extraneous lines, most likely to be attributed to impurities. In order to check the foregoing assumption, two specimens of an alloy containing 43 pct by weight of cobalt, 41 pct molybdenum, and 16 pct chromium, which was within the composition range of stability of both the D-phase at 1300°C and of the R-phase at 1200°C, were homogenized at 1200 and 1300°C, respectively, and quenched. X-ray diffraction patterns of the powders of these two specimens, obtained with CrK radiation, were compared carefully with each other and with the D-phase pattern previously

Jan 1, 1959

By S. F. Radtke, J. A. Snyder, R. M. Scriver

An automatic, continuous casting arc furnace employing a nonconsum-able electrode and a direct current arc has been constructed and operated successfully for titanium. A comparison of the properties of arc and induction-melted titanium indicates that where high ductility, formability, and toughness are required, arc-melted metal is preferable. BECAUSE of the reactivity of titanium metal with all known refractories and the common atmospheric gases, melting of the metal presents numerous problems. It is necessary to provide an inert atmosphere in the furnace as well as a crucible material that will not react with the molten metal, if a ductile ingot is to be produced. Two special furnaces have been developed that meet the requirements and one, the induction heated graphite furnace, has been described in some detail.' Little information is available for sizable units wherein power is applied to the melt through an arc, and the dearth of technical information on such a furnace prompted this report. It has been demonstrated clearly that arc melting produces titanium metal with superior toughness, ductility, and formability. To produce titanium ingots with these properties, an automatic, continuous casting arc furnace has been developed and is described herein. The history of arc melting may be traced to 1800, when Sir Humphrey Davy2 first experimented with Volta's electric battery and found that light could be produced and an arc formed between two carbon points attached to the cell. The discovery of the arc was followed by the design and construction of an arc furnace by Napier," in 1845, for the reduction of metal oxides. In 1853, Pichou' described a similar furnace, although it was not until the discovery of the dynamo in 1867 that the arc furnace could achieve commercial significance. In 1878, Siemens- esigned the first arc furnace intended for the melting of metals and by 1882 had melted steel and platinum successfully. . This was followed by Moissan's" classical work with the arc furnace in 1892. W. von Bolton,' in 1905, found that the arc furnace was suited admirably for melting refractory metals. In his work with tantalum, no suitable refractories for retaining the molten metal were found to exist. Together with Otto Simpson, he developed an arc furnace with a water-cooled copper crucible in which tantalum could be melted without contamination. This technique proved eminently successful. In his paper on the preparation of ductile titanium, Krolle first described an application of the von Bolton furnace to the melting of this metal. The

Jan 1, 1952

By Edward Wisser

The environment of an ore body is taken to mean not only its physical surroundings but every factor, passive or active, that conditioned the ore shoot, saving only the original composition of the solutions that formed the shoot. Collection of data related to the shape and characteristics of veins should be followed by correlation of the data and the formulation of generalizations regarding ore formation. The nature of the criteria used in arriving at these generalizations is discussed. Certain of the criteria, when used with an understanding of their underlying causes, become "ore-guides." In the course of his study the geologist must not confine himself to the immediate surroundings of the veins, but should attempt to work out the geologic history of events culminating in the crucial epoch for any mining district, the period of mineralization. The work may involve study of features far removed from the veins and related to them only indirectly. It commonly means thorough study of the geology of the entire region surrounding the ore deposits. The following question has been suggested for discussion: "Are there any criteria by which one can determine when mining operations have reached the roots of an ore deposit?" The question deals less with the roots of a particular ore body than with the lower limit of the vertical range within which ore bodies may be expected. It concerns a critical line upon the longitudinal vertical projection of a vein.† Below this line it is useless to look for ore shoots; above the line exploration below the bottoms of individual ore shoots may be justified. Can we learn to determine the position of such a line? In some multivein districts the line for any given vein may be approximated by simple interpolation or extrapolation. Where this is possiblc the bottoms of the lowest ore shoots in the various veins are points on an imaginary, gently rolling surface. The trace of this surface upon the vein is our critical line for that vein. The imaginary surface rolls so gently that it may be projected from two or more known veins to an unexplored vein near by. Here is a criterion for the bottoming of ore that has nothing to do with changes in the appearance of the vein in question; it rests solely on the depth at which the ore bottomed in adjacent veins. The method is not applicable in districts only slightly explored in depth, nor where the lower limit of the ore-bearing horizons

Jan 1, 1941