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By J. A. Elias, A. J. Heckler

A simplified method is described for the prepauatior~ of comnposite samples for determination of one quadrant of an X-ray pole figure of a sheet material by the Schulz reflection method. Other special conzposite sampling methods were used to investigate specific areas of the pole figures. Plotting nets for these sampling plans were drawn by a computer. Step-scanning techniques were used to obtain detailed information about specific regions of a pole figure. Satisfactory pole figures were obtained for large-grained (0.5 to 1 in. diam) sheet materials. COMPOSITE sampling techniques for preparing one quadrant of an X-ray pole figure have been reported by a number of authors.'-5 All of these methods are similar in that they use a composite sample prepared by stacking and holding together coupons cut from a sheet material. The schulze reflection technique is applicable to the composite sample so that only minor corrections are needed for defocusing and absorption effects. Also, a relatively large area of a sheet is sampled through the use of multiple cross sectional pieces. In general, sampling methods necessary to obtain a composite-type specimen have been formidable enough to discourage their use in routine pole figure determinations. This paper presents a versatile sampling technique which is simpler than those previously described along with an accurate method for obtaining stereographic plotting nets for any orientation of a composite specimen surface. A step-scanning technique is used to obtain more quantitative determinations of specific regions in pole figures, and the composite technique is satisfactorily applied to determine pole figures of very large grained sheet materials. REVIEW OF PREVIOUS TECHNIQUES Mueller and ~nott' first proposed a technique for obtaining one complete quadrant of an X-ray pole figure by using a sheet sample and six different composite samples in which the individual coupons were aligned and held together by two types of jigs. Data from the seven different samples were overlapped to obtain a single quadrant. ~eieran~ and Lopata and ~ula~ obtained a complete quadrant of a pole figure from a single sample prepared by forming a cube from coupons cut from a sheet. These coupons were bonded together using an epoxy cement, and a cut was made at 54.7 deg to the normal, transverse, and rolling directions of the sheet, Fig. I. The normal direction of the cut face projects into one quadrant of a stereographic projection at equal angles to the three principal orthogonal reference directions mentioned above. X-ray reflection data obtained along a spiral path in physical space could then be plotted on a stereographic net offset 54.7 deg from the normal, as shown in Fig. 2. A rotation about an axis representing the surface normal is designated as a, and a rotation about an axis lying in the plane of the surface is 4. From Fig. 2 it is apparent that a tilting angle of no more than 55 deg @ is necessary to obtain the complete quadrant. ~eber~ devised an improved sampling technique by cutting coupons 45 deg to the rolling direction of a sheet, stacking and bonding these with an epoxy cement at an angle of 54.7 deg to a reference plane, and finally grinding and lapping a flat specimen surface parallel to this plane. An important consideration of this technique and that of Lopata and ~ula~ is variation in the diffracting power of the specimen surface due to the bonding medium. While any composite-type sample will have some such variation due to boundaries between coupons, the problem can be minimized by elimination of the bonding medium and by avoiding prolonged etching times which could lead to significant inter lame llar attack of the coupon faces. EXPERIMENTAL TECHNIQUE We were working concurrently though independently on a technique similar to ~eber's,' but which does not

Jan 1, 1968

By Yinchang Wang

1. INTRODUCTION 1. Subject, and Scope The formation of the oxidized ores of zinc has been recognized as a subject of great importance in economic geology. For many years these ores have been much sought, partly because they are more desirable for metallurgical treatment and partly because they are apt to be freer from gangue than is the sulphide of zinc. Up to very recent years the oxidized ores were the principal source of the metal and at present they still furnish a large portion of the commercial production. . The oxidized ores of zinc include six minerals, as shown in the-following table

Jan 9, 1915

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 B. C. Burgess

IN the first edition of this volume,44 feldspar was introduced as "the I commonest mineral of the crystalline rocks," usually in small grains associated with other minerals and commercially produced only from pegrnatites. Now other crystalline rocks, such as alaskites and granites, have become present or potential sources of feldspar. In addition, feldspar has encountered very vigorous competition from such substitutes as nepheline syenite and aplite. COMPOSITION AND PROPERTIES The feldspars form a group of which the principal species are orthoclase, microcline, albite, and anorthite. These are aluminum silicates of potassium, sodium and calcium. There are also a barium feldspar, celsian, and barium orthoclase feldspar, hyalophane, rarely found and of no commercial importance. None of the minerals in the feldspar group are found pure or nearly pure. The potash feldspars, orthoclase and microcline, nearly always contain some albite (soda microcline, an- orthoclase); the soda feldspars usually contain some anorthite (lime feldspar). There is a series of soda-lime feldspars known as plagioclase in which the albite and anorthite molecules replace each other in varying proportions from albite through oligoclase, andesine, labradorite, and bytownite to anorthite. Theoretical chemical composition of the principal feldspars is given in Table 1. The Whiteware Division of the American Ceramic Society sub- mitted a list of definitions of ceramic terms, in April 1947, for use in technical literature. For feldspar it gives: "A group of igneous minerals consisting chiefly of the aluminum silicates of potash, soda and lime, in which one base generally predominates." Commercial feldspars are intergrowths of at least two species of feldspar, which occur associated with one or more accessory minerals such as quartz, muscovite, biotite, garnet and tourmaline as well as with small but varying proportions of the decomposition product, kaolinite. An intergrowth of quartz and feldspar frequently contains

Jan 1, 1949

By Paul D. V. Manning

MAGNESIUM is an exceedingly strategic material but the importance of its production at the time this war started was not realized. Our Government then suddenly became much alive to the need of a tremendous increase in magnesium output, and became a participator in the industry. In this paper an attempt will be made to given an over-all picture of the industry as it has been, and is being, developed. The present war is giving a great acceleration to the use of lighter metals. Development of facilities for production of great tonnages of aluminum and magnesium is bound to bring about some interesting changes in later peace times because costs will be low and production capacities high. As our knowledge of the metallurgy of magnesium alloys increases, this metal will become of vital peacetime importance and will be used in ways we do not now imagine. Household refrigerators, furniture, automobiles, even houses will all be lightened through the use of magnesium.

Jan 1, 1943

By Peter Tegart

The discovery of gold in the Toodoggone River area is credited to Charles McClair who mined placer deposits in 1925, reportedly valued at $17,500. After he and his partner went missing in 1927, efforts to relocate their workings resulted in the formation of Two Brothers Valley Gold Mines Ltd. in 1933, in which the legendary Grant McConachie (first president of CP Air) played an active role. This was the age when the prospector first utilized the airplane to reconnoitre remote areas. What greeted the observer from the air was an area rich in orange and yellow colours characteristic of gossans formed by the oxidation of sulphides. However, Samuel Black, a Hudson Bay Company fur trader, had also noted in his diary as early as 1824, the unusual and many gossanous colours in the headwaters of the Finlay River. These gossans, coupled with white limestone bluffs and the presence of placer gold, attracted the first reconnaissance of the area by Cominco in 1929. Cominco was ever active in remote areas at this time. They staked and worked several base-metal showings hosted by limestone at the margins of intrusive stocks. These early workers also obtained erratic high gold assays from chalcedony float samples found in creeks draining into the Toodoggone River. However, because the samples gave inconsistent assays, no concerted effort was made to locate their source. Except for the occasional horse-supported prospecting party of the late 1940s and early 1950s, the area did not receive much attention until 1968. Work until this time focused on the base metal lead-zinc showings which contained attractive silver credits. Gold was not an attraction because of the set price established by the US government. The late 1960s saw the northward expansion of porphyry copper exploration into the Toodoggone. A program of gossan soil sampling (gossans which had attracted the early workers) was carried out by Kennco Explorations (Western) Ltd. in 1966-1967. They analysed for base metals in the field, using a cold extraction method. The Kemess copper- gold prospect was staked as a result of anomalous copper values from this early geochemical program. In 1968, Kennco continued the program of silt traversing and field geochemical testing. The samples were further subjected to multielement analysis consisting of copper, molybdenum, lead, zinc, cobalt, nickel, and silver at Kennco's North Vancouver laboratory. Several anomalous creeks, high in combinations of copper, molybdenum, and silver, were outlined. Some initial soil grids were also established. The fall of 1969 saw the return of Kennco prospector Gordon Davies and geologist Bob Stevenson to check out a well-defined molybdenum, scattered copper and silver anomaly in soils from a grid on the Chappelle claims. The subsequent analysis of several selected quartz felsenmeer floats yielded one assay which ran in the order of 0.25 kg/t (8 oz per st) gold and 2.2 kg/t (70 oz per st) silver. Subsequent trenching on the Chappelle claims exposed the source of float in a 4- m (134) wide vein of high grade gold-silver mineralization. These results led quickly to the realization that the district had precious metal potential. Subsequent exploration in the period 1969-1974 by Kennco resulted in the discovery of most of the gold and silver occurrences on the Chappelle and Lawyers properties. Several other gold and silver occurrences were found in this district by Cordilleran, Cominco, and Sumitomo, working the district during this period. Conwest optioned the Chappelle in 1973 and explored underground by adit entry as part of a one-year program. In 1974, Du Pont of Canada Exploration Ltd. optioned the Chappelle claims and in March 1980, using reserves developed on the A vein, placed the Baker mine into production at a rate of 90.7 Vd (100 stpd). The Amethyst zone on the Lawyers property, 8 km (5 miles) north of Chappelle, was found in 1973 by Kennco using continued, persistent followup prospecting of silver silt geochemical anomalies. A silt anomaly in the order of 3.4 ppm silver occurred in a stream flowing 300 m (984 ft)

Jan 1, 1985

By John T. Awald

The Bradshaw Mountains of west-central Arizona cover an area of 1600 square miles and contain numerous old mines and prospects. The area has been geochemically sampled on a reconnaissance basis to relate mineralized areas to regional structure and rock types. Copper analyses of stream sediments have been classified and contoured to show the distribution of low and high backgrounds and low, intermediate, and highly anomalous areas. Contoured results are compared to geology and known mines. Several prospecting areas are indicated.

Jan 1, 1972

ALABAMA Altoona.-Cain, J. America.-Foreman, J. T. Anniston.-Cowie, L. K. Foster, R. N. Ashland.-Sturdevant, J C Bessemer.-Ball, E. M. McKenzie, W. C., Jr Birmingham.-Abbott, C. E. Aldrich, T. H. Aldrich, T. H, Jr. Ashton, J J. Ball, T. L. Blair, C. S. Brown, T S. Bush, M. W.

Jan 1, 1923

By ERIIL SCHROEDTER

THE death, on May 6, 1908, of Dr. Hermann Wedding, Privy Mining Councilor of the Kingdom of Prussia, and Professor of the Metallurgy of Iron and Steel at the Royal Mining Academy of Berlin, was a loss keenly felt by the whole metallurgical world. Not alone in his native land, but also in foreign countries did he enjoy an esteem of which the title of honorary membership in the American Institute of Mining Engineers, the United States Association of Charcoal Iron-Workers, and the (British) Iron and Steel Institute bears eloquent testimony. Hermann Wedding was born March 9, 1834, in Berlin. At the suggestion of Dr. C. J. B. Karsten, the veteran father of Prussian metallurgy and author of the first German text-book of the metallurgy of iron, lie turned his attention, after gradu¬ating from the gymnasium, to mining and metallurgy. In 1853, he began a practical course at the Malapane iron-works, in Upper Silesia. Subsequently, he studied at the Berlin Mining Academy, and received from the University in 1859 the degree of Doctor of Philosophy. A journey which be made to England, somewhat later, led to his undertaking a German translation, with revision and additions, of John Percy's classic treatise on the metallurgy of iron and steel, the publication of which, in successive installments, stretched through many years. In 1863, lie published, as a thesis in connection with his "Assessor's examination," an essay, entitled The Results of the Bessemer Process for the Production of Steel, and Its Prospects for the Rhenish and Westphalian Iron and Steel Industry, which revealed such ability and knowledge as to secure for him a call to the chair of metallurgy in the Berlin Mining Academy.

Jun 1, 1909

By J. J. Carrigan

IN all mining operations a considerable portion of the work performed, especially underground; is accomplished under artificial light, yeti this subject is often not given proper attention. Poor illumination decreases mining efficiency, impairs the sorting or grading of ores, and increases the risk of accidents. In the beginning, and for several years afterward in the metal-mining industry of Butte, Montana, candles placed in candlesticks were carried by the men. Sconces or holders for candles were also provided at stations and curves in drifts to furnish better light for men engaged in. hand tramming. It was also common practice to place clusters of candles on the ground, with no provision for guarding against an underground fire other than the exercise of sufficient care by the men themselves. An accumulation of candle grease from this source was the direct result of the first serious fire in the Anaconda mine, in 1889.

Jan 1, 1936

By J. T. Ryan

WITH J. T. Ryan, of Pittsburgh, in the chair, 40 men on Monday afternoon were attracted to the first meeting of the new Health and Safety in Mines Committee. The speakers were well received and the discussion was good and virile. The field and scope of the new Health and Safety in Mines Committee was reviewed briefly, yet concisely, by Scott Turner. This committee is to cover the whole mining industry, in which much progress in reducing accidents has been made in recent years. Members of the A.I.M.E. can considerably assist in this important problem.

Jan 1, 1933

BASIC open-hearth slags have no obviously unique features when compared with slags from other metallurgical operations. Open-hearth slags form and exist at temperatures ranging from 2500 to 3100 F (1370 to 1700 C). In the course of an open-hearth heat, the liquid slag changes slowly and continuously in chemical analysis-the changes reflecting changes in temperature, changes in metal analysis, solution of charged materials, solution of feed additions, and solution of refractories. Throughout the process, the slag performs specific primary functions that are responsible for a large measure of the technical and economic importance of basic open-hearth steelmaking. It is intended in this chapter to present the chemical reactions by which the primary functions of basic open-hearth slags are carried out, to describe the physical and chemical principles governing the extent to which these reactions proceed and can be regulated, and finally to indicate the limitations imposed on other features of the process by the fulfillment of the primary functions. Basic open-hearth slags perform three primary functions. First and foremost, the slag provides a means of removing phosphorus from the liquid metal. The ability to remove phosphorus is largely responsible for the widespread use of the basic open-hearth process. Second, the slag serves as a controlling factor in transferring the oxygen required for the other oxidizing reactions. Third, the slag provides a means of eliminating some sulfur from the open-hearth bath. While the extent of sulfur removal is not comparable to that of phosphorus, the ability to remove some sulfur contributes much to the value of the process. The effectiveness with which the slag fulfills its functions varies with temperature and composition. Since operating temperatures are fixed largely by the specified nature of the product and the equipment, .the speed and extent to which the functions of the slag are carried out depend largely on its composition. The necessity for regulating slag composition to accomplish the re-

Jan 1, 1964

By Max Roesler

Page I. Introduction........................... 78 Location.......................... 78 Scope of Work and Acknowledgments.............. 79 History and Mining...................... 80 I1. Topography and its Interpretation................. 80 III. Petrology............................ 82 Sedimentary Rocks...................... 82 Description....................... 82 Age.......................... 84 Igneous Rocks........................ 85 Diabasic Rocks..................... 86 Dioritic Rocks...................... 87 Granitic Rocks...................... 88 Later Dike Rocks.................... 88 IV. Areal Geology.......................... 88 Rock Types Found in the District............... 88 Distribution of the Various Rock Types............. 89 Surface Distribution................... 89 Vertical Distribution................... 90 Causes of Present Areal and Vertical Distribution of the Various Rock Types..................... 91 Faulting...................... 91 Magmatic Differenti~tion............... 91 Tilting........................ 95 Erosion....................... 96 V. General Description of Ore Deposits................ 96 Nature of Ore ........................ 96 Shap~ and Size of Orebodies.................. 96 Geologic Position....................... 97 Mineralogy......................... 98 Distribution....................... 98 Interpretation...................... 99 Superficial Alteration................... 102 VI. Genesis of the Ore Deposits.................... 104 Previous Theories...................... 104 J. P. Kimball...................... 104

Jan 1, 1917

By Willis T. Burns

I. Introduction.......................................... 703 II. History................................................ 703 III. General Description of Plant......................... 704 IV. AnoDes................................................. 711 V. Cathodes............................................... 714 VI. Electrolyte............................................ 718 VII. Electrolytic Slime..................................... 727 VIII. Power................................................. 728 IX. Operating Details..................................... 732 X. Furnace Refining...................................... 736 XI. Physical Testing oF Products.......................... 739 I. Introduction. These notes are submitted, not as a discussion of the modern practice of electrolytic-copper refining, but as the record of a refinery that was among the pioneers in the field and that is to-day, and has been for 17 years, operating under conditions not to be found in any similar plant in the country. I refer to the current density, which is at least 60 per cent. higher than that regularly employed elsewhere, and to the fact that the anodes treated are the direct product of the converter rather than of the reverberatory furnace. The writer has no knowledge of any other refinery treating anodes of this character. II. History. This refinery, now one of the oldest plants of its kind operating in this country, was built in 1892 by the Boston & Montana Consolidated Copper & Silver Mining CO. to refine the product of its Great Falls reduction works. The estimated capacity of the plant as designed was 65,000 lb. of cathodes per day at a current density of 16 amperes per square foot.

Jan 1, 1914

By P. D. Merica, J. R. Freeman, R. G. Waltenberg

Contents Page Constitution of Commercial Aluminum.................. 4 Solubility of CuAl2 in Aluminum at Different Temperatures........ 9 Effect of Magnesium on Solubility of CuA12 in Aluminum ......... 15 Solubility of Mg4Al8 in Aluminum at Different Temperatures........ 15 Solubility of Metals and Metal Compounds in Aluminum.......... 20 Summary and Conclusions......................20 Aluminum and its alloys have been the subject of much investigation1 during recent years, in the course of which the principal features of the constitution of most of the binary alloy systems with aluminum have been determined. Except in the case of a few metals—silicon, bismuth, cadmium, lead, zinc, and tin—an aluminum-rich compound is formed in each binary system, which forms a eutectic with the aluminum or its solid solution with this compound: Thus such compounds as FeAla, CuA12, Mg4Al3, and NiAls are formed, which are found in aluminum-rich alloys of their respective series as eutectics with the aluminum solid solution. These compounds are, in all cases, hard and brittle and their presence affects profoundly the physical properties of the alloys in which they occur. Within the zinc-aluminum system a compound, Al2Zn,, is formed that decomposes at lower temperatures. Silicon and tin each form a simple eutectiferous series with aluminum; bismuth, lead, and cadmium are only partly miscible in the liquid state with it. The extent of the solubility in aluminum, in solid solution, of these compounds or of the elements themselves, in the case of those series in which compounds are not formed, is of the greatest importance in

Jan 1, 1921

By L. O. Millard

Stockpiles in the minerals industries serve a wide variety of purposes. Usually they are for surge between stages of processing, for a dependable plant feed in anticipation of delays, or to provide for single or double shift mining in conjunction with round-the-clock milling. Often surge piles are necessary to insure a uniform feed to continuous process equipment where the material is received as an intermittent or variable flow. Extensive use is made of stockpiling for the primary purpose of blending. The significant fact about all stockpiling of bulk materials is that storing and reclaiming are two separate and distinct operations and they may present widely different problems in the selection of methods and tools.

Jan 10, 1959

By Alexander R. Troiano, Taylor Lyman

Studies of the transformation of aus-tenite at constant subcritical temperatures have been numerous since the work of Davenport and Rain.' Considerable information has been obtained on low-alloy steels and on high-carbon alloys containing undissolved carbide or graphite at the austenitizing temperature. Little is known of the isothermal transformation of aus-tenite containing in solution large amounts of both carbon and a single alloying element. In this investigation four steels containing one per cent carbon and with chromium in the range 3 to 9 per cent have been examined with the view to establishing the fundamental character of the isothermal reactions when all carbon and chromium are initially in solution in austenite. Experimental Procedure Alloys The chemical compositions of the steels investigated are given in Table I. The 4 per cent Cr alloy is a commercial steel. The other steels were made by the Carpenter Steel Co. as 50-lb., induction-furnace heats and rolled to 5/8 -in. round bars. Bars were softened at 650' to 700°C. before the specimens were cut. Most of the lines on the transformation diagrams presented here have been placed on the basis of the microscopic examinatioll of partially reacted specimens, Thees specimens were approximately 1/2 by 1/4 by 1/8 in. ill size, specimens of the 9 per cent cr steel were held 10 to 12 hr, at 1200°to 1225°C. before quenching to the various subcritical temperatures. The other steels were held for 2 to 2 1/2 hr. at 12ooOC. before quenching. These treatments, carried out in an atmosphere of purified nitrogen, produced an austenite grain size larger than A.S.T.M. So. I, some grains being 1 to 2 mm. in diameter. There were a few undissolved carbide particles in some specimens of the 9 per cent Cr steel. It is believed, however, that any errors in the results due to incomplete solution of carbon and chromium in austenite are negligible; that is, austenite compositions may be considered as being those listed ill Table I. X-ray Methods Constituents were identified and mar-tensite axial ratios determined from Debye

Jan 1, 1945

By Richard L. Gordon

Minerals long have been important commodities in international trade. As an inevitable result, the governments of the world have employed a wide variety of programs that affect the flow of trade. Roughly speaking, we may distinguish between the desire of more developed countries (MDCs) like the United States, western Europe, and Japan to control imports of minerals and the concern of less developed countries (LDCs), like India, about exploiting and exporting their minerals. The terminology used to describe different countries and the classification of specific countries into groups is unsettled and often changing. The poorest countries have been characterized as backward, undeveloped, underdeveloped, and developing. The problem seems to be in selecting a term that is both accurate and polite. Less developed seems, for reasons outlined by Hagen [pp. 51-57], the most convenient term. The borderline between an LDC and an MDC is always open to dispute. Objective measures are difficult to develop because of deficiencies in basic data, and enormous conceptual problems arise in making valid comparisons from even good data [see Hagen, pp. 7-28]. Thus, policies of the MDCs can be evaluated chiefly by using a few basic arguments for protectionist attitudes towards international trade. In dealing with the LDCs, a more far-ranging evaluation that covers general economic policy goals, the role of foreign investment, and the indirect effects of trade is required. This duality breaks down when trying to deal with the depressed areas in an MDC; here the issues are more akin to those associated with problems in an LDC. Similarly, variants of arguments used in LDCs appear in debates about foreign investments in MDCs. The whole discussion of minerals in LDCs, moreover, has obvious implications for MDCs like Canada and Australia. They, too, must face problems about the best utilization of their resources. THE RESTRICTION OF MINERAL TRADE BY DEVELOPED COUNTRIES[a] At least to some extent, the world's leading industrial nations have intervened to control the inflow of minerals. Such regulation is particularly pronounced for energy. Both the United States and western Europe employ

Jan 1, 1976

HE purpose of this chapter is to present a general outline of the basic open-hearth process for the benefit of students, practicing open-hearth operators, and metallurgists who wish to review the subject. The discussion is limited to a description of the sequence and purpose of the operations, illustrated by data and examples. Subsequent chapters deal with more detailed and fundamental studies of the subject. The function of the basic open-hearth furnace is to convert various types of ferrous material into finished steel of given composition and quality. In comparison with other steelmaking methods, the basic open-hearth process is one of the most versa- tile, both from the standpoint of the raw materials that can be used and the types of steel that can be produced. The process can be considered as a sequence involving melting, refining, and deoxidation. With some types of liquid-metal charges, the melting stage is not present, but refining and deoxidation in varying degrees are fundamental features of the process. GENERAL DISCUSSION OF BASIC OPEN-HEARTH PROCESS The first consideration in open-hearth practice is the type of charge on which the operation is based. This consists of three components-fluxing, oxidizing, and metallic materials. Fluxes. In the basic process the fluxing material is primarily lime, added in the form of either limestone (CaC03) or burnt lime (CaO). This is supplemented by magnesia (MgO) and lime from the furnace bottom and banks. The function of these fluxes is to form a slag with the silica (SiO2) , manganese oxide (MnO), iron oxides (FeO and Fe2O3), and phosphorus oxide (P2O5) that are produced by the oxidation of varying amounts of the silicon, manganese, iron, and phosphorus in the charge during melting and refining. The slag, composed of the basic fluxes and the neutral and acid oxides, floats on top of the steel bath when the charge is melted. The composition of this slag depends on the amount of each slag-forming element present in the charge and on the extent of oxidation of these elements during the course

Jan 1, 1951