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By E. W. Schilling

THE-separation of hematite by hysteretic repulsion was first brought to the attention of the public in 1922, by W. M. Mordey1. Three-years later another paper2 was published and after another four years a third paper3 appeared in the South African publications. Certain data were lacking in these papers. In order to continue the work intelligently a knowledge of the shapes of the hysteresis curves for certain minerals was very necessary. This information was not available until the present year4. It was known that reduction of certain ores rendered them amenable to this process of separation but definite data in. the form of curves showing exactly the effect of such treatment were lacking. Prob-ably our best source of information on the separation of minerals by the use of alternating-current magnetic fields today is the reports from the U. S. Bureau of Mines 5-7. It is not the purpose of this paper to tell the reader in detail how to make a commercial separator. Experimental models have recently been made7 and the results obtained have been so good that it is the opinion of the authors that the public will soon take an active interest in the subject and its development. The writers have constructed a separator that is considerably different in construction and operation from the two types described by Mr. Davis. This will be described; but the real purpose of this paper is to outline certain experiments and give curves showing data that have a fundamental bearing upon the practical construction of a separator of this type.

Jan 1, 1936

By R. L. Grayson, Y. J. Wang

This paper presents an application of goal programming (GP) to major mining machinery purchases based on historical operating data on mechanical downtime and production. The GP technique, an extension of integer programming, is used to maximize an objective function comprised of deviations away from management-preferred financial goals. Different capital budgeting techniques are used to evaluate capital proposals, and the results of these analyses are combined and weighted in a maximization of profits objective function. The GP method gives an optimal solution to a multiple goal problem. A sensitivity analysis is performed to determine the effect of a variable production improvement condition or a variable budget control con¬dition on proposal selection.

Jan 1, 1984

By George Steintveit

Det Norske Zinkicompani A/S was established in 1924, on the initiative of the Compagnie Royale Asturienne des Mines. Experimental electrothermic zinc production was carried out on industrial scale for a two-year period, but the problems of electrothermic smelting were not solved. A license for the electrolytic zinc production process was then obtained from the Anaconda Copper Mining Co. A plant for electrolytic zinc production was built, near the small fjord town of Odda in Hardanger, West Norway, The production was based on zinc ore from Spain, and cheap local hydro-electric power. The plant came into operation in 1929. Annual capacity, 36,000 tons. In 1964 a long-term agreement was concluded with Boliden AB by which Det Norske Zinkkompani is secured the raw materials basis for an expansion of the annual capacity to 100,000 tons of zinc, Since World War II, the company has been pursuing extensive research and development programs. As a result, various sections have been rebuilt: nev unloading and storage facilities, a 250 ton per day Fluid Bed Roaster with contact plant, new continuous leaching system, integrating the Jarosite Residue Process, new solution purification section - upgrading the solution quality for a 600 Amp/m2 current density Tank Room operation -, installation of induction furnaces for cathode melting with casting machines and automatic stacking of slabs. Simultaneously, instrumentation, and methods of automatic control have been developed and introduced, providing conditions for optimal plant operations.

Jan 1, 1970

26. G. H. S. Price, S. V. Williams, and G. J.O. Garrard: Heavy alloy, its production. properties and uses. Metal Industry (1941) 599 354s 372. 394. 27. R. Kieffer and W. Hotop: p. 320 of ref 12. 28. F. R. Hensel. E. I. Larsen, and E. F. Swazy: Physical properties of metal compositions with a refractory metal base. Chap. 42, 483, Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. 29. R. Kieffer and W. Hotop: p. 290 of ref. 12. 30. H. Freundlich: Kapillarchemie. 211 (1923) Leipzig. 31. W. Ostwald: Zisch. f. Phys. Chemie. (1900) 34, 503. 32. G. A. Hulett: Zisch. f. Phys. Chemie. (1901) 37. 385; and (1904) 47, 357. 33. J C. Chaston: Discussion to Price, Smithells and Williams, p. 257 of ref. 4. 34. W. Dawihl: Untersuchungen ueber die Vorgaenge bei der Abnuetzung von Hartmetallwerkzeugen. Ztsch. f. techn. Phys. (1940) 21 336. 35. W. Dawihl and J. Hinnueber: Ueber den Aufbau der Hartmetallegierungen. Kol-loidzlsch. (1943) 104, 233. 36. F. Skaupy: Dispersoidchemische und verwandte Gesichtspunkte bei Sinter-hartmetallen. Kolloidzlsch. (1942) 98, 92; and (1943) 102, 269. 37. F. C. Kellcy: Cemented tantalum car- bide tools. Trans. ASST (1932) 19, 233. 38. E. W. Engle: Cemented carbides. Chap. 39, 436, Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. 39. W. Dawihl: Zlsch. f. Melallkunde. (1940) 32, 320. 40. P. M. McKenna: Tool Materials (Ce- mented Carbides). Chap. 40. 454. Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. 41. G. A. Meerson. G. L. Sverev, B. Y. Osinovskaja: Zhurnal Prikladnoi Khimii. (1930) 139 66. 42. A. G. Metcalfe: The mutual solid solubility of Tunesten Carbide and Titanium carbide- Metal Trealmenl (1946) 13, 127. 43. P. Schwarzkopf: Powder Metallurgy. 196-201 and 354-356 (1947) New York. 44. H. Burden: The manipulation and sintering of hard-metals. Special Rep. No. 38, p. 78. Iron and Steel Inst.. 1947. London. 45. W. D. Jones: Principles of powder metal- lurgy. 150. (1937) London. 46. J. E. Drapeau: Sintering of powdered copper-tin mixtures. Chap. 32. 332, Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. 47. H. E. Hall: Sintering of copper and tin powder. Metals and Alloys (1939) 10, 297. 48. F. Sauerwald: Present status of powder metallurgy. -.Melallwirlschafl. (1941) 20, 649. 671. 49. H. L. Wain: Powder metallurgy; influence of some processing variables on the properties of sintered bronze. Report ACA-25. Australian Council for Aeronautics (1946) Melbourne. 50. S. L. Hoyt: Constitution of copper-tin alloys. Metals Handhook, 1364. (1939) Cleveland. 51. T. Ishikawa: Studies on the interdiffusion of copper, tin and graphite powders. Nippon Kinzoku Gakkai-Si (1937) I, 226. 52. A. Carter and A. G. Metcalfe. The struc- ture of porous bronze bearings. Special Rep. No. 38, p. 99. Iron and Stecl Inst. (1947) London. 53. R. P. Koehring: Sintering atmospheres for production purposes. Chap. 25, 278. Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. 54. C. G. Goetzel: Some properties of sintcred and hotpressed copper tin compacts. Trans. AIME (1945) 161, 569. 55. J. W. Lennox: The production of some non ferrous engineering components by powder metallurgy. Special Rep. No. 38. p. 174. Iron and Steel Inst., 1947, London. . P. Duwez and H. E. Martens: The power metallurgy of porous metals and alloys having a controlled porosity. TP 2343, Metals Tech. April 1948. This volume. p. 848. 57. E. A. Owen and L. Pickup: X-ray study of the interdiffusion of copper and zinc. Proc. Royal Soc., London, Series A. (1935) 149, 283. 58. C. G. Goetzel: Sintered and hotpressed compacts of copper-zinc powder. Chap. 34. 352, Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. 98, R. Chadwick. E. R. Broadfield, and S. F. Pugh: Observations on the pressing. sintering, and properties of iron-copper powder mixtures. Special Rep. No. 38, p. 151, Iron and Steel Inst. (1947) London. 60. A. Squire: The properties of iron-copper compacts. Watertown Arsenal Lab. Rep. WAL No. 67101. 61. F. C. Kelley: Properties of sintered iron- comer uowder. Iron Age (Aug. 15. 193) 158 57. 62. G. H. Howe: Sinterinn of Alnico. Iron Age (Jan. 11. 1940) 14.5, 27. 63. R. Kieffer and W. Hotop: p. 359 of ref. 12. 64. W. Hotop: Permanent magnets from sintered iron-nickel-aluminum. Stahl und Eisen (1941) 61, 1105. 65. P. R. Kalischer: Some experiments in the production of aluminum-nickel-iron alloys by powder metallurgy. Trans. AIME (1941) 145, 369. 66. S. J. Garvin: Production of sintered per- manent magnets. Special Rep. NO. 38. p. 67. Iron and Steel Inst. 1947, London. 67. F. C. Kelley: Discussion to P. R. Kalischer. p. 375 of ref. 65. 68. R. Kieffer and W. Hotop: p. 357 of ret, 12. 69. C. H. Howe: Sintered alnico. Chapter 48, 530, Powder Metallurgy, ed. by J. Wulff (1942) Cleveland. Powder Metallurgy Seminar (C. G. Goetzel presiding) C. G. Goetzel—The seminar has been opened by a man who has been active in the field for over fourteen years and has made, since then, some major contributions to the advancement of the art. After having been associated with the Moraine Products Division of General Motors Corporation for over ten

Jan 1, 1949

By A. J. Langhammer

Broadly speaking, it may be said that the engineer has two major responsibilities: One is to recommend the choosing of proper machinery and equipment; the other, to assist in the simplification of design, determination of method, and advise about the most suitable material to be used. The products of powder metallurgy enter broadly into both these fields. The oil-cushion, self-lubricating bearing surface on a machine part makes for better machinery and factory equipment, often proves a life-saver in curing difficulties where bearings are overloaded or inaccessible for lubrication, or on installations that with normal practice constitute a problem entailing frequent repairs. On the other hand, other parts may require low porosity approaching solidity. In the second field, powder metallurgy provides many possibilities for improved products, improved performance, solving of technical problems, saving of weight, quiet operation, higher factors of safety, greater flexibility, attractive economies, and so on. Parts We of the automotive industries are making many powdered-metal war-machine parts, both ferrous and nonferrous, including gears, external and internal; ratchets, both external and internal; levers; pillow blocks; sliding blocks; cams; gibs; hubs with external and internal splines, and similar units. Powdered metals play an important part in our war work, as they did in peacetime in the manufacturing of passenger cars and trucks. The art of powder metallurgy is not a panacea. Although on certain parts such operations as turning, boring, facing, reaming, counterboring, milling, countersinking. chamfering, broaching, hobbing, profiling. trepanning, gear cutting, grinding, etc., can be eliminated, there will always be the need for machine tools. Advantages of Powder Metallurgy Simple machining operations often are eliminated by using powdered metal, and also many other intricate operations, some of which are of the type impossible to perform on the most modern production equipment; for instance, an external spline on a flange hub, where the spline must continue to the flange face and at full depth. Another important feature is that some of the machine parts may require a self-lubricating surface at one or more points; for example, proper lubrication of a sliding splined spool, while ordinarily most digcuit, is accomplished automatically with a self-lubricating powdered-metal bearing. Frequently machine parts are made with physical, mechanical and technological advantages unobtainable from cast or forged metals of similar analysis. Thus powder metallurgy offers the designing engineer broader latitude. Similarly, the engineer may take advantage of powder metallurgy in his teamwork with other departments. Another important advantage in powder metallurgy for machine parts is the relatively short time required for tool-up.

Jan 1, 1945

NEW MEMBERS. The following list comprises the names of those persons who became members during the month of April, 1913: BARNES, BLAKESLEE, Min. Engr Burrwood, La. BOYLSTON, HERBERT M., Cons. Met. Engr 26 Abbot Bldg., Cambridge, Mass. BUEHLER, HENRY A., State Geol Rolla, Mo. CASTO, WILLIAM H., JR., Mining Bonanza, Idaho. COHEN, MAXWELL B., Mill Operator Miami, Ariz. EVANS, MILTON R., Shop Draftsman 92 Division St., Kingston, Pa. HARPER, WALTER S., Asst. Treas 42 Broadway, New York, N. Y. JAMES. JAMES S.. Min. Engr Telluride. Colo.

Jan 5, 1913

By Frank Firmstone

IN Chemical Phenomena of Iron Smelting, Mr. Bell gives the weight of materials required to fill furnaces of various sizes at the Clarence Works ; as this differs very much from the weight required for furnaces at Glendon, where anthracite and magnetic and brown iron-ores are used, a comparison is interesting. Taking furnaces at Glendon of 4800 and 11,900 cubic feet capacity and comparing them with the Clarence furnaces of 6000 cubic feet and 11,500 cubic feet, we find that the 4800 cubic feet at Glendon and the 6000 cubic feet at Clarence required respectively-

Jan 1, 1873

Abbott, Franklin E. Adgate, Frank Aertsen, G. Aid, Kenneth Albert, H. I. Alexander, D. B. W. Allan, Wm. G. Allen, R. 0. Allen, Roy H. Aller, Mr. and Mrs. F. D. Altmayer, Maurice Ambler, Harry A. Ambrose, A. WV. Ammon, Mark A. Ammon, Mr. and Mrs. Robt. Anderson, George H. Anderson, Mr. and Mrs. L. D. Andros, S. 0. Appleby, W. R. Archer, R. S. Armitage, Paul Arobb, Alden D. Arthur, Walter Ashman, A. 0. Atkinson, R. H. Aupperle, J. A. Austin, D. F. Avery, G. E.

Jan 11, 1919

By AIME AIME

THE second blast furnace of the Azov steel mill was blown in on Feb. 17, says the Economic Review of the Soviet Union. This furnace, the 111th in the U. S. S. R., has a volume of 930 cubic meters, and a daily output of 775 tons of pig iron. The 1934 program at the Azov plant includes three 250-ton-open-hearth furnaces, two coke-oven batteries, a repair shop, mine and agglomeration plant at Gamysh-Burum, and two ports, one at the latter town and one at Mariupol. On Feb. 21 the sixth open-hearth furnace of the Stalinsk (Kuznetsk) mill started operations; on Feb. 12 the fourth open-hearth furnace at the Liebknecht mill at Dniepropetrovsk, produced its, first steel, 47 tons of high-grade boring steel. The fourth open-hearth furnace

Jan 1, 1934

By Richard Miller

RECENT studies of creep have made it apparent that plastic deforma-tion may occur in metals under stresses less than the elastic limit as deter-mined from short-time tests. In summarizing conclusions drawn from creep tests by various investigators, Tapsell1 said: "It is evident that if a material has a true elastic range, the elastic limit must represent the maximum stress for no creep." The presence of a. definite elastic limit, represented in single crystals by a critical or threshold shearing stress, is claimed by Schmid2, Elam3 and others who have investigated the plastic deformation of single crystals. However, this "law of critical shearing stress" was deter-mined2 from short-time tests, and the measurement of the deformation was made with apparatus primarily designed to observe large amounts of plastic deformation, not to detect elastic changes. Experimental data recently obtained with highly sensitive instru-ments by A. W. Hanson4 on zinc and by Podaschowsky5 on rock salt indicate that the elastic range in single crystals is considerably narrower than formerly was supposed. Moreover, a theoretical possibility of permanent deformation, under the influence of even the smallest shear stress in single crystals above a certain temperature (Td), has been developed by G. I. Taylor6. This evidence seemed to warrant an examination of the elastic limit in large single crystals by means of creep tests. The first metal chosen for examination was zinc.

Jan 1, 1936

By Franklin Bache

There seems to be in the public mind, and even in the minds of some coal-operators not experienced in mines subject to dust-explosions, a feeling that there has been somet-hing mysterious at the bottom of a number of recent American colliery-exploaions. It has been declared in cases of accidents in mines regarded as particularly well equipped, in which every preventive precaution was said to have been taken, that the explosions were incomprehensible, and resulted from causes beyond the present knowledge of the practical coal-operator. But it is safe to say that no explosion has taken place which could not be explained by reasons well understood by most operators. The U. S. Geological Survey Testing Laboratory, recently inaugurated at Pittsburg for the reported purpose of investigating scientifically the matter of explosions in mines, will discover no new explanation of explosions. It can, however, co-ordinate the previous investigations of similar boards in England and on the Continent; and it may do a vast amount of good by promulgating widely, and in a form comprehensible to the most unlettered miner, certain facts and obvious deductions that cannot but have an effect in reducing the number and extent of the mine-disasters which, in the last few years, have been so terrible in frequency and magnitude.

Jan 1, 1910

By Thomas T. Read

THE fact that certain types of ore-deposits have attained their present condition through the action of descending surface waters was, perhaps, first clearly pointed out by Posepny.1 The oxidizing effects of such waters were discussed by Penrose,2 and many papers dealing with this phase of the subject have subsequently appeared. That secondary enrichment of sulphide ores, however, might be produced by descending surface waters was not clearly understood until after the copper-bearing veins of the Butte district, Mont., had been carefully studied by the geologists of the U. S. Geological Survey, al¬though De Launay3 had suggested that sulphides might be transported from point to point and re-deposited in the zone above the level of ground-water. As a result of the study of the Butte district, two papers by geologists engaged in the work appeared within a short interval. The first by Weed,4 dealing with the enrichment of veins by later metallic sulphides: and the second by Ernmons,5 treating of the secondary enrichment of ore-deposits in general. In the latter paper it was pointed out that a typical vein of sulphide ores which has been subjected to the action of descending surface waters exhibits four zones,-an upper or surface zone, in which the changes have been mainly of removal, the products being typically oxides; a second zone of oxide enrichment, in which the less soluble metals brought from above have been precipitated as carbonates or oxides; a third zone of sulphide enrichment,

Mar 1, 1906

By James L. Calver

Fuller’s earth is an inexact term applied to certain clays that have a marked ability to adsorb coloring materials from animal, vegetable, and mineral oils. Many clays have this adsorbing power to a slight or very limited degree, and certain other clays, chiefly bentonites, as well as minerals such as bauxite, can be made highly adsorbent by activation with acids or alkalies, but the term fuller's earth is generally reserved for clays that are naturally highly adsorptive. In most fuller's earths and practically all activable clays montmorillonite is a dominant mineral. No definite clay mineral or group is implied in the name fuller's earth, and the distinction between fuller's earth and other clays that have more or less bleaching power is not sharply drawn. The name as generally used has no genetic or mineralogical significance. The fuller's earth produced in the Florida-Georgia district contains the clay mineral attapulgite. This mineral name was first used in 1930 by DeLapparent to apply to a hydrous aluminum magnesium silicate found in the fuller's earth from Attapulgus, Ga., and Quincy, Fla. An essential component of its structure, determined by Bradley in 1940, is that the silica chains of the molecule are arranged similarly to those of the amphibole minerals. The fibrous nature of the lath-like crystals of attapulgite is apparent under magnifications reached by the electron microscope. The ideal formula, [(OH,), (OH), Mg, Si, 0,-4H,O], contains no aluminum, but there is considerable replacement of the magnesium by aluminum. In the classification of clay minerals, attapulgite is associated with sepiolite and polygorskite rather than with mont-morillonite.

Apr 1, 1956

By F. Wartenweiler

Much has been written on milling and cyanidation as practiced on this gold field, therefore the purpose of this paper is to record its development only briefly and to describe in more detail the contemporary state of the science and art of this branch of metallurgy. It is a pleasing task, because a steady evolution is to be recorded. Definite trends influenced the development. Some have the stamp of original thought and observation; many have been achieved from a logical sequence of planned experimentation and research; while others have resulted from the drive of sheer necessity. The large scale of operations and capital outlay has compelled conservative progress. Banket ORe For a better understanding, a review of the characteristics of the ore may not be out of place. The Witwatersrand gold ore is named "banket" from the similarity of the oxidized outcrop ore to the Boer almond cake of that name. The inter bedded orebody is commonly called "reef." It is a conglomerate composed of various sizes of pebbles, principally non-gold-bearing white quartz, which constitute about 70 per cent of the bulk, within a matrix of cementing material consisting of fine-grained quartz, sericite, chlorite and chloritoid and containing the precious metals and mineral sulfides. Argillaceous components in the mil pulp may be as high as 32 per cent. Of the sulfide minerals, pyrite and pyrrhotite are predominant. Most base-metal sulfides are present, but sporadically and generally only found in highly concentrated mill products. In the latter, osmiridium is recovered in varying amounts; from 1 oz. in 3000 tons to 1 oz. in 10,000 tons of ore. Most of the oxidized ore has been mined, so milling is confined principally to the sulfide ore. A typical analysis of sulfide ore is: silica (SiO2), 86.76 per cent; pyritc (FeS2), 2.75; ferric oxide (Fe2o3), 2.65; alumina (Al2o3), 6.91; lime (CaO), tr.; magnesia (MgO), 0.70; sp. gr., 2.7. Milling grade at present price of gold (137 shillings per ounce) varies from 3.5 to 8.5 dwt., with one mine milling ore as high as 16 dwt. The

Jan 1, 1935

By Thomas T. Read

The fact that certain types of ore-deposits have attained their present condition through the action of descending surface waters was, perhaps, first clearly pointed out by Posepny.l The oxidizing effects of such waters were discussed by Pen-rose,2 and many papers dealing with this phase of the subject have subsequently appeared. That secondary enrichment of sulphide ores, however, might be produced by descending surface waters was not clearly understood until after the copper-bearing veins of the Butte district, Mont., had been carefully studied by the geologists of the U. S. Geological Survey, although De Launay3 had suggested that sulphides might be transported from point to point and re-deposited in the zone above the level of ground-water. As a result of the study of the Butte district, two papers by geologists engaged in the work appeared within a short interval. The first by Weed: dealing with the enrichment of veins by later metallic sulphides ; and the second by Emmons; treating of the secondary enrichment of ore-deposits in general. In the latter paper it was pointed out that a typical vein of sulphide ores which has been subjected to the action of descending surface-waters exhibits four zones,—an upper or surface-zone, in which the changes hare been mainly of removal, the products being typically oxides; a second zone of oxide enrichment, in which the less soluble metals brought from above have been precipitated as carbonates or oxides; a third zone of sulphide enrichment,

Jan 1, 1907

By J. M. W. Mackenzie

A microelectrophoresis technique has been used to measure the zeta potential of quartz over a range of pH and ferric iron concentration. The results have been discussed in terms of the adsorption of ferric cations and ferric hydroxide to the quartz surface. Possible relationships between the experimental results and the flotation of quartz have been examined. The adsorption of multivalent cations at the surface of quartz has been studied by many investigators who have used a variety of experimental techniques ranging from streaming potential 1 to radiometric2 measurements. Two possible mechanisms of cation activation of quartz have emerged from the results of these investigations viz: the adsorption of the cation to the negatively charged quartz surface, followed by adsorption of the collector anion to the adsorbed cation site, or: formation of a cation-collector complex which is then adsorbed to the quartz surface. In many natural and industrial systems one of the most prevalent activating species for quartz is ferric iron, this is especially so in the acid-circuit, anionic flotation of iron ore. The adsorption of ferric iron to the quartz surface is complicated by the ability of ferric iron to form complexes with anions, a phenomena which is of minor importance in one of the most widely studied quartz activation processes, ca ++ activation.* *The pK value for [ca(oH)+]/ [ca2+] [oh-] is 1.46 indicating that the influence of Ca (OH)+ ions will be minor in all but strongly alkaline solutions. In order to obtain a better understanding of quartz activation by ferric iron the zeta potential of quartz in the presence of ferric iron has been measured over a range of pH and ferric iron concentration. EXPERIMENTAL METHODS Materials: Selected samples of "rock clystal" quartz from New England, N.S.W., were ground in a pebble mill, washed for three hours in boiling concentrated hydrochloric acid, washed in hot chromic acid and then washed repeatedly with distilled water until the washing water gave no trace of chloride ion.

Jan 1, 1967

By K. Thirumalai, D. P. Schlick

Longwall Technology has a potential of resulting in safety and productivity improvements of U.S. underground coal mining similar to those experienced by the introduction of continuous miner systems. The study presents a comprehensive national evaluation of longwall technology to assess the potential of longwalls to improve health and safety and coal productivity. The study was conducted by the authors during the spring of 1980 as part of MSHA New Technology Coordination activities and with a view to examine the factors that may limit the acceptance of longwall technology in the U.S. coal mining operations. The study points out areas where adjustments need to be made in MSHA regulations and enforcement to help Longwalls. A two-entry longwall system appears to offer a practical method of improving underground coal productivity and safety. Applying regulations that are primarily designed for room and pillar methods to longwall mining, in some instances, reduces the effectiveness and productivity benefits feasible by new technology application. Controlling dust is the single predominant problem in the design and operation of longwalls in the United States. The results of this study points out a need for a coordinated program between government and industries on dust control technologies for examining acceptable technological options to control dust in longwalls without restraining the production capability of the system.

Jan 1, 1981

By C. G. Dunn

According to a recently suggested effect of silicon on the re recrystallization textures of high-purity Fe-Si alloys with (111)[112] type rolling textures, the recrystallization texture for a rolled (110)[001] oriented iron crystal probably should be entirely different from that of a (110)[001] oriented 3 pct Si-Fe crystal. Comparative studies of iron and 3 pct Si-Fe crystals, however, show that both have (110)[Ool] recrystallization textures when the rolling textures are the (111)[112] type after reductions in thickness of about 70 pct. Qualitatively the results from the iron crystal are like those of polycrystalline high-purity 3 pct Si-Fe and not like polycrys-talline high-purity iron. The large effect previously noted probably involves unknown impurities or processing variables rather than silicon itself. Some problems on experimental and analytical procedure for a spherical X-ray specimen, which was machined from a laminated composite of sheet specimens, are treated in the Appendix. A possible strong effect of silicon on the textures produced in cold-rolled high-purity Fe-Si (HPFe-Si) alloys during primary recrystallization and normal grain growth was suggested in a recent paper.' All the textures were far from the random-orientation type, but that of iron, or of Fe-Si alloys of low silicon composition, was entirely different from the texture of 3 pct Si-Fe. The same effect was noted for the textures obtained prior to normal grain growth, i.e., for primary recrystallization.2 It is the main purpose of the present paper to provide some clarification of this silicon effect. All the HPFe-Si alloys from zero to 3 pct Si, which were rolled by two or more stages separated by anneals, developed (111)[112] type rolling textures.2 Thus, there was no effect of silicon on the rolling textures. Earlier, Gensamer and Mehl3 also found no effect of silicon on the rolling textures of Fe-Si alloys; they obtained the Kurdjum.ow and Sachs (K-S) rolling texture for iron,4 which is characterized as the three ideal components: (100)[011], (112)[li0], and (111)[112]. There is a difference between the HPFe-Si multiple-stage rolling texture and the K-S single-stage rolling texture, but this is a variable processing effect. Of interest here is the fact that the recrystallization textures from (111) [llZ] type rolling textures were different depending on the amount of silicon in the alloy. There was a relatively strong (110) [001] component in the recrystallization texture of HP 3 pct Si-Fe5,8,2 but no such component in HP 0.6 pct Si-Fe, for example; the recrystallization texture for the latter was two (111) [110] type components and a (111) fiber component 1,2 Several publications have shown that a strong (110) [001] recrystallization texture is derivable from a (111) [112] type rolling texture for 3 pct Si-Fe crystals reduced in thickness by about 70 pct.7-10 Furthermore it appears that the strongest of these (110) [001] recrystallization textures occurred when the orientation of the crystal prior to rolling was (110) [001].7 Barrett and evensoon11 found that the rolling texture of a (110)[001] oriented iron crystal was (111) [llj]. Accordingly, it seemed desirable to determine whether a (110) [001] oriented iron crystal, upon rolling and annealing, would behave like the 3 pct Si-Fe crystal (or the polycrystalline HP 3 pct Si-Fe) and thus produce a (110) [001] recrystallization texture contrary to the suggested silicon effect, or would behave like the polycry stalline HP iron or HP 0.6 pct Si-Fe and thus produce (lll) [110] type components in agreement with a silicon effect. Briefly, the idea here involves the use of more precisely defined textures to obtain if possible better control of important variables that affect the recrystallization process. PROCEDURE A (110) oriented crystal of Ferrovac "E" iron (99.9 pct pure) was prepared in sheet form 0.080 in. thick with the [001] direction parallel to the long dimension of the specimen.'' This crystal was etched to 0.073 in. thickness (to remove some small included grains) and then was cold rolled in a 6-in.-diam mill to a final thickness of 0.022 in. The rolling was unidirectional except for an inadvertent reversal at 0.061 in. thickness. At this thickness, and also at 0.040 in., the rolling was interrupted for transmission Laue photographs. Molybdenum Ka-radiation filtered with zirconium was used in a transmission method1' to obtain the cold-rolled (110) pole figure. The sample was a 0.002-in.-thick section taken from the central region of the 0.022-in.-thick cold-rolled crystal. For the primary recrystallization study, cold-rolled samples were etched from 0.022 to 0.021 in. thick and annealed in hydrogen at 850°C. Primary recrystallization to a fine-grained structure, Fig. 1, was obtained in a 5-min anneal. Eleven sheets after

Jan 1, 1963

By Arthur F. Taggart

The following notes represent significant excerpts from a mass of records of experimental work done in the ore-dressing laborattory at the Columbia School of Mines during the years 1926 to 1928 inclusive. Classification of Experimental Work The experiments performed may be grouped for purposes of description under the following general headings: I. Collecting agents. a. A method for quantifying collecting effect. b. Coating with undissolved collecting agents (oils). c. Action of dissolved collecting agents. II. Frothing agent's. a. A method for quantifying frothing effect. b. Relation between frothing effect and chemical composition. III. Inorganic reagents. a. Methods of studying the effects of these reagents. b. Effect on slime dispersion. c. Effect on sulfides. Summary of the Origins of Present-day Flotation Practice The first practicable, foolproof method of froth flotation was described in U. S. Patent 835120, issued in 1906 to Sulman, Picard and Ballot, and in the equivalent patents in other countries. A number of less simple methods of producing the same result had been described previously in patent publications and otherwise.' The reagents specified in all of these early patents were "oils" and, in addition, some inorganic substance, usually an acid. The quantities of reagents recommended and added were enormous when compared with those used today.

Jan 1, 1930

By J. Leslie Goodier

The International Law of the Continental Shelf, so far ratified by 35 nations, extends the national boundary of any coastal nation to the edge of the continental shelf, this normally being at a continuous water depth of 200 m. The Law further extends this boundary to include the floor of the deep ocean to any depth that can be mined by advanced mining technology. In effect, proof of mining can constitute proof of ownership of the subaqueous land and the minerals on or below the sea floor. Irrespective of the fact that present technology is too limited to permit mineral exploitation in the high seas-and the law regarding the right to mine appears hazy-the U. S. Treasury Department's Bureau of Customs, has a ruling that would further deter mining operations on the high seas. This law contends that minerals mined on the continental shelf of the United States are actually mined within the continental United States and are free of tariff, but mined products or other articles obtained from the ocean or the sea floor beyond the continental shelf, if brought into this nation, must be considered as imported and are subject to such customs duties as are applicable under the tariff schedules of the United States.

Jan 7, 1968