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Jan 2, 1953

By H. E. Cline

Solidification of Pb-Sn alloys ranging in composition from 1.2 to 56 at. pct Pb ws observed with polarized light. Lamellar structures were observed over a larger range of compositions in alloys containing excess tin than excess lead, as expected from constitutional supercooling. The occurrence of pools of supercooled liquid surrounded by lead is explained by the difficulty in nucleating tin. Cells and dendrites weve observed in tin-rich alloys. Evidence was found that the degenerate structure formed at low growth rates, the formation of faults, and abrupt changes in composition and structure can be attributed to non-steady-state growth. The apparent interface shape was observed to have deep grooves at the interphase boundaries. HUNT and Jackson have observed the shape of the interface during growth of organic eutectics. They observed the formation of lamellar faults and shape instabilities upon changes in growth rate. The lamellar structure in these organic eutectics was not restricted to the eutectic composition. Recent work by Mollard and Flemings2 indicated that Pb-Sn alloys from 12 to 26 at. pct Pb could be solidified with a lamellar or rodlike structure if a sufficiently steep temperature gradient was used at a slow growth rate. Observations of the solid liquid interface of the Pb-Sn eutectic were made by Davies3 using polarized light. Photographs were at too low a magnification to determine the interface shape, but he has concluded that tin was the leading phase. In the following experiments, solidification of a range of Pb-Sn alloys from 1.2 to 56 at. pct Pb was observed using polarized light, to determine the factors controlling stability of the lamellar structure. EXPERIMENTAL Procedure. One hundred-gram ingots of alloys prepared from 99.999 pct pure Pb and Sn were cast into graphite molds under argon. The compositions of the alloys were 1.2, 6, 12, 26, 36, 46, and 56 at. pct Pb. Two-gram pieces were melted between two cover glass slides which were squeezed into a 1-mm separation. Samples were then observed under polarized light in a hot stage shown in Fig. 1. A long working distance objective designed for viewing at 500 times was used. Photography was made difficult by the lack of illumination and contrast at these high magnifications. By using an elliptical polarization compensator, as suggested by A. Holik, the contrast and illumination could be optimized. Photographs could be taken only at slow growth rates to avoid excessive interface motion during the 15-sec exposure used. The solidification rate was varied by increasing or decreasing the power to the heater. It was found that insulation was necessary to avoid undesired growth rate fluctuations. The temperature gradient, as measured with two thermocouples 1 cm apart, was 80" ± 20°C per cm during all the experiments reported here. The advantage of this procedure is in being able to observe solidification while it is occurring. However, the observations are restricted to the glass-metal surface and may be influenced by this surface. Also, one has no knowledge of the interior of the sample, in contrast to studies of the freezing of transparent organic eutectics.' Observations. The alloy near the eutectic composition (26 at. pct Pb) solidified in a lamellar structure when the growth rate was uniform. If the growth

Jan 1, 1968

By Charles A. Stetefeldt

This treatise is the sequel of a paper on "Russell's Improved Process for the Lixiviation of Silver-ores," etc., read at the Chicago meeting, in May, 1884, and published in the Transactions, vol. xiii., page 47. The facts it presents are principally compiled from Mr. Russell's notes on his practical experience gained in various places where the Russell process has been introduced. For a complete understanding of this paper a perusal of my former one is desirable, as can be seen from the frequent references here made to it. All silver-ores that do not carry a large percentage of lead or copper can be treated by Russell's process with success and economy. I do not mean to create the impression that from ores containing considerable quantities of lead and copper a high percentage of the silver cannot be extracted by this process. Such ores, however, will, in many localities, be reduced to better advantage by smelting. In case lead-bearing silver-ores are suitable for concentration, it may be profitable to concentrate the ore by Krom's dry system, obtaining a smelting-product high in lead, and to lixiviate the tailings and the dust. This plan has been adopted in a mill recently erected in Cortez District, Nevada. The dry system of concentration deserves the preference because it delivers the tailings and the dust in a condition ready for chloridizing-roasting. In wet concentration the drying of the tail ings would be expensive, and there would be a considerable loss of silver in slimes. Oxidized ores, containing silver chloride and lead minerals, may be lixiviated after crushing, and the tailings may be concentrated for lead. In this case wet concentration would be most suitable. This has been done at the Old Telegraph Mine, Utah. I would give, however, the preference to dry concentration in all cases which, of course, requires that concentration should precede lixiviation. The Russell process is also adapted to the treatment of tailings resulting from ores which have been worked either by the old

Jan 1, 1887

By H. De Cizancourt

The Pechelbronn (Alsace) field is the only important French producing field. During 1934, development was carried on as in previous years. The total output of this field reached 553,575 bbl. in 1934, showing a slight decrease from the 1933 figures. Of the total, 315,000 bbl. (56 per cent) was extracted by drilling, while 238,875 bbl. (46 per cent) was obtained by means of shafts and galleries. Exploration of deep Jurassic and Triassic horizons was still in progress at the end of 1934. A deep well reached the Upper Triassic at a depth of 34 m. (2736 ft.). (Information kindly supplied by M. S. Mena, Directeur Technique.) As mentioned before, the small Gabian field (Herault) is gradually being exhausted. No drilling operations were undertaken in 1934, the small production being restricted to the pumping of old wells. Two exploration wells, noted as "drilling" at the end of 1933, were completed in 1934; viz., Lavelanet (Ariége) at 3785 ft. and Santenay (Niévre) at 2578 feet. French Possessions Algeria.—No drilling at Tliouanet. Out of a total of 100 wells drilled in the area, only 8 are still producing. No exploration work is reported during 1934 in Algeria. Tunisia.—Two wells completed; one well drilling at the end of 1934. A total of 11 wells is reported to have been drilled before the beginning of 1935; out of these, 8 were completed before the present program was begun. Morocco.—Exploration work progressed actively last year. The outstanding event was the coming in of Ts. 26 well at 1243 ft. This well took fire, therefore great difficulties were encountered in the accurate measurement of initial production; the figure of 1500 bbl. of oil given here is a near estimate. Oil flowed accompanied by a great amount of water. The apparent decrease of drilling operations in 1934 is explained by the increase in field activities after the results of Ts. 26 were known;

Jan 1, 1935

By Roy G. Mead

BECAUSE of its magnitude, and the type of occurrence, the deposit of boron minerals in the Kramer district, Kern County, California, is unlike any other in the world. Discovery of this vast deposit has brought about many changes in the borax industry, so a discussion of the geology, and the occurrence, would not be complete without a brief history of the development of the borax industry. Until the discovery of boron minerals in the desert regions of California and Nevada some seventy years ago, borax was imported from Tibet and India, principally for medicinal purposes, at almost prohibitive prices. Following the discovery of commercial deposits of boron minerals in California and Nevada, and the subsequent development of new uses for borax and boric acid, the consumption has steadily increased until today borax is used in some form or other in every household.

Jan 1, 1933

By Paul Tyler

STRATEGICALLY situated in almost the heart of the leading fertilizer-consuming area of the United States, Tennessee long has ranked second only to Florida as a phosphate-producing state. Since 1932 its share of the national output of phosphate rock has increased steadily, and in 1937 its production mounted to an all-time record. More significant even than the increase in tonnage are the forward strides in technology. The Tennessee Valley Authority's research program has led to quasicommer-cial operations using hydroelectric power to manufacture concentrated phosphatic fertilizer that is used to further the farmer education program designed to streamline the fertilizer business and halt the appalling waste of farm land by soil erosion. Even more stimulating to chemically minded imaginations is the production of elemental phosphorus by a private company that not only has succeeded in extracting it from the phosphate rock in electric furnaces but actually has contrived to capture it and to transport it safely in tank cars. New values have been created for low-grade phosphate deposits, and the economic life of reserves has been lengthened while the waste of former years goes back into the mills for recovery of its values by modernized methods. Tennesse's phosphate-mining industry dates from the discovery of blue rock in Lewis County in December 1893. Its known reserves are of the order of 101,500,000 tons, which compares with the production of 825,099 tons in 1937; that is, 21 per cent of the phosphate-rock output of the whole nation. The total output reported from 1894 until July 1, 1938, was approximately 19,000,000 tons. Official estimates of reserves are overly conservative and evidence submitted before a joint Con-gressional committee in November 1938 places "probable" reserves at more than 6,000,000,000 tons.

Jan 1, 1939

By Donald A. Brobst

The minerals barite (BaSO4-barium sulfate) and witherite (BaCO3-barium carbonate) are the chief commercial sources of the element barium and its compounds whose many uses are nearly hidden among the technical complexities of modern industrial processes and products. Barite, the major ore mineral, is extremely vital to the petroleum industry which in 1980 consumed at least 90% of the world's production of 8.8 million tons as a major ingredient of the heavy fluid, called mud, that is circulated in rotary drilling of oil and gas wells. The remaining 10% of the barite production was consumed chiefly in the manufacture of barium chemicals and glass and as a pigment, filler, and extender. Barite occurs throughout much of the world and is available from three major geologic types of deposits-vein and cavity filling, residual, and bedded-in sufficient quantity at competitive prices to meet current demands. The world's demand for barite is expected to increase, and geologic circumstances are favorable for the discovery of new deposits of commercial value. Witherite is much less common and abundant than barite, although it is more desirable in many ways as a raw material for the production of barium chemicals. The United States has not produced witherite since about 1950; England is currently the chief producer of witherite. End Uses Most of the world's barite production since 1926 has been used as a weighting agent for the muds circulated in rotary drilling of oil and gas wells. The muds fundamentally are mixtures of water, clay, and barite in different proportions that vary according to local reservoir conditions. Muds with a specific gravity as great as 2.5 are used. The mud is pumped down the hollow drill stem, passes through the bit at the bottom of the hole, and rises to the surface in the space between the drill stem and the wall of the hole. In the course of this circulation the drill bit is cooled, cuttings are removed, the drill stem is lubricated, the walls of the hole are sealed, and the hydrostatic head of the column of weighted fluid helps to confine high oil and gas pressures. The latter feature aids in prevention of gushers, thus reducing both environmental pollution and waste of oil and gas resources as well as conserving the natural reservoir pressure for greater production and rate of recovery of the products contained in the rocks. Barite is particularly well suited for drilling mud because it is clean, easy to handle, soft (nonabrasive), heavy, virtually inert chemically, and relatively inexpensive compared to many other available heavy materials. Barite is used in the manufacture of glass in continuous tanks. The addition of barite homogenizes the melt and gives greater brilliance and clarity to the finished glass. Ground barite, both unbleached and bleached by sulfuric acid, is a common industrial filler, extender, and weighting agent. The rubber industry is a major consumer of barite as a filler. Barite also is added to bristolboard, heavy printing paper, playing cards, rope finishes, brake linings, clutch facings, plastics, and linoleum, to name but a few uses. Bleached barite has long been an extender in white lead paint because of its weight. The low index of refraction of barite, however, makes its ability to cover marks poorer than some other substances, but its low capacity for absorption of oil is a good feature. Off-color or unbleached barite can be used as a filler in colored paints. In the construction industry, some lump barite is used in concrete aggregate to weigh down pipelines buried in marshy areas and to shield nuclear reactors. Because barite absorbs gamma radiation well, its use reduces the amount of expensive lead shielding otherwise

Jan 1, 1983

By J. W. Pugh, J. D. Nisbet

THIS study of the ternary has been made as one phase of a metallurgical investigation which began nearly four years ago in the General Electric Company's Research Laboratory in Schenectady, N. Y. The objective of this program is the discovery of new metallurgical information which will lead to the development of better high-temperature materials. Combinations of the four pure base elements—iron, chromium, nickel, and cobalt—are being studied at the present time. It is essential in an investigation such as this to know as much as possible about the constitutional diagrams involved. The study of the iron-chromium-nickel system has been made to this end. Preliminary Explanation of Experimental Procedure: In all, fifty-five alloys at steps of 10 at. pct were made for the investigation of this ternary. Several ternary alloys in the chromium rich corner had to be omitted because their extreme brittleness made testing impractical. All alloys were vacuum melted with hydrogen reduction and centrifugally cast. The apparatus and technique of this process has been described in detail by Nisbet.1,2 The purity of the alloys prepared in this way is considered to be quite good. Impurities are listed as follows: Pct Carbon.............................0.02 Oxygen................................0.02 Nitrogen.........................0.005 Magnesium..................0.03-0.05 Sulphur...........................trace Hydrogen....................trace Phosphorous..................trace Silicon........................ trace After casting, all samples were given a homo-genization treatment which consisted of holding them for 15 hr at 1150°C (2100°F) and water quenching. Testing was begun with the samples in this condition. The tests employed in the study of this system were (1) dilatometer, (2) hardness versus aging temperature, (3) tensile strength and elongation versus temperature, (4) microstructure analysis, and (5) electrical resistance versus temperature. Dilatometer tests were made at the rather rapid heating rate of 1093°C (2000°F) in one hour on a Bristol-Rockwell type instrument. Hardness data were taken on specimens cooled from 204", 427", 649°, 760°, 871°, 982°, and 1093°C under conditions which are thought sufficient to bring the specimens to equilibrium in all but the cases of the very sluggish transformations. Electrical resistance data for several specimens were taken for both heating and cooling conditions in a vacuum furnace especially designed for this work by D. W. Bainbridge, formerly of this laboratory. Provisions were made for heating and cooling standard specimens at a constant rate, while autographic records of resistance and temperature were made simultaneously. Micrographs of all the alloys were made in the quenched condition. Some question may exist as to how such physical values as hardness, tensile strength, and elongation were interpreted to indicate a change in phase. Original data were recorded on physical property versus temperature graphs, each of which was made from the data of a single alloy (fig. la). From these, another series of graphs were plotted with the physical property as a function of composition for constant temperatures (fig. 1b). Sharp deviations in the slope of these composition versus hardness curves often indicate a change in phase. The example of fig. 1 will serve to describe this experimental technique. The plotting of a single point from graph "a" to graph "b," and finally to the phase diagram "c," is illustrated. The location of the point on graph "b" is indicated as point (1). If all the alloys of the A-B binary system were solid solutions at temperature X, the hardness in this curve would be expected to rise at a fairly even rate as A is diluted with B to a maximum at some intermediate value between A and B, as

Jan 1, 1951

By P. R. Bradley

NO thought had been given to deep level mining at the Alaska Juneau mine prior to 1930, but in that year a prospect winze was started and continued for 1000 ft. vertically below the main haulage or adit level. The point at which this winze was started was selected entirely by the prevailing physical conditions, such as proximity to established workings, convenience, and the presence overhead of a substantial pillar of dimensions sufficient to lo¬cate the sheave wheel and loading pocket. It was, therefore, with some surprise that the unusually high-grade ore found just below the collar of the winze persisted, with certain vari¬ations, to a full depth of 1000 ft. vertically. Likewise this unusually high-grade ore was found to persist on the various crosscuts driven on levels at 200-ft. vertical intervals. To be brief, this deep level work found richer ore than any yet found in the mine over like areas, and inasmuch as the area was sufficient to plan for extensive deep level mining, plans for such work were given extended consideration.

Jan 1, 1936

By E. J. Wasp, N. T. Cowper, R. A. Davis, W. F. McDermott

On October 26, 1967, the world's first long distance iron ore slurry line was put into service by Savage River Mines. The commissioning of this $5 million installation climaxed three years of development, testing, and construction. The mine and concentrator are located approximately 30 miles from the town of Waratah in a rugged semi-mountainous terrain. The open pit mine will produce approximately 5 million long tons a year of crude ore, which is ground in autogenous mills, separated magnetically, thickened and prepared for the pipeline. The 53-mile pipeline transports the 2,250,000 tons of concentrate north to Port Latta. The Port Latta facilities include the receiving, storage and thickening equipment for the slurry as well as filtering, balling and pelletizing equipment to produce the 2,250,000 tons of high grade iron ore pellets. Five vertical shaft furnaces are used for pelletizing.

Jan 1, 1969

By L.L. Wyman

The exact nature of the changes that take place in the iron-nickel alloys, giving rise to the interesting and useful expansion alloys in the Invar range, has yet to be fully understood. Similarly, the ternary iron-nickel-cobalt alloys, which also possess such commercially useful expansion characteristics,1,2 are concerned with transformations that appear to be identical with those found in the parent iron-nickel alloys. The investigations on iron-nickel alloys in the range 26 to 29 per cent Ni have been reported by several authors3-9 wherein it is shown that there are factors other than temperature, such as stress and grain size, which play an important part in determining the temperature at which the low-temperature transformation takes place. It will be shown in this paper that the ternary iron-nickcl-cobalt alloys having nickel contents comparable to the alloys mentioned above behave in a parallel manner. The alloys in the range of 26 to 31 per cent Ni and 16 to 21 per cent Co have a coefficient of expansion of about 4.0 X 10-6 per degree Centigrade, and the alloys in this range of composition find considerable application in making glass-to-metal seals, because these expansion properties so well match commercial glasses. The behavior of these alloys is not a simple matter, for it has been observed in alloys of 28.5 per cent Ni and 18.5 Co that severe working ran cause the appearance of a second phase having a needlelike structure similar to the martensite structure in carhon steels. Fig. 1 shows the change brought about in an alloy of this composition when a strip of this material was cut with tin shears. This second phase has been identified as the body-centered cubic alpha phase, and it is the purpose of this paper to describe the results of some of the preliminary investigations in the study of the changes involved in these alloys. Materials The past work on these alloys has concerned itself primarily with materials made by the usual casting procedure and involving the use

Jan 1, 1939

By L. L. Wyman

The exact nature of the changes that take place in the iron-nickel alloys, giving rise to the interesting and useful expansion alloys in the Invar range, has yet to be fully understood. Similarly, the ternary iron-nickel-cobalt alloys, which also possess such commercially useful expansion characteristics,1,2 are concerned with transformations that appear to be identical with those found in the parent iron-nickel alloys. The investigations on iron-nickel alloys in the range 26 to 29 per cent Ni have been reported by several authors3-9 wherein it is shown that there are factors other than temperature, such as stress and grain size, which play an important part in determining the temperature at which the low-temperature transformation takes place. It will be shown in this paper that the ternary iron-nickcl-cobalt alloys having nickel contents comparable to the alloys mentioned above behave in a parallel manner. The alloys in the range of 26 to 31 per cent Ni and 16 to 21 per cent Co have a coefficient of expansion of about 4.0 X 10-6 per degree Centigrade, and the alloys in this range of composition find considerable application in making glass-to-metal seals, because these expansion properties so well match commercial glasses. The behavior of these alloys is not a simple matter, for it has been observed in alloys of 28.5 per cent Ni and 18.5 Co that severe working ran cause the appearance of a second phase having a needlelike structure similar to the martensite structure in carhon steels. Fig. 1 shows the change brought about in an alloy of this composition when a strip of this material was cut with tin shears. This second phase has been identified as the body-centered cubic alpha phase, and it is the purpose of this paper to describe the results of some of the preliminary investigations in the study of the changes involved in these alloys. Materials The past work on these alloys has concerned itself primarily with materials made by the usual casting procedure and involving the use

Jan 1, 1939