Search Documents

By F. J. Wiebelt

Production of small tonnages of asbestos has been reported from 18 California counties; 16 additional counties have occurrences of asbestos. The counties in the northern part of California that have had a recorded production are: Alameda, Amador, Calaveras, Contra Costa, E1 Dorado, Napa, Nevada, Placer, Shasta, Siskiyou, Trinity, and Tuolumne. No deposit in the State has maintained consistent production. Serpentinized peridotites (potential chrysotile-bearing rocks) are widely distributed in the coast ranges, Klamath Mountains, and western foothills of the Sierra Nevada.

Jan 1, 1958

By Charles B. Kenahan

The chemical and galvanic corrosion properties of commercially pure titanium, a titanium-manganese alloy, a titanium-aluminum-tin alloy, 2 titanium-copper alloys, and 2 titanium-aluminum alloys were studied. Tests were conducted in synthetic ocean water, tapwater, 1-percent sodium hydroxide, 5-percent ferric chloride, and 5-percent ammonium sulfate solutions, various concentrations of sulfuric and hydro-chloric acids, and 1-percent oxalic acid. All tests were carried out at 35° or 60° C., with a flow of air or helium. Dissimilar metals involved in galvanic-couples experiments were aluminum, magnesium, and stainless steel. Electrode-potential measurements on single (uncoupled) specimens were also measured. Commercially pure titanium and the titanium-base alloys were generally quite similar in their resistance to corrosion, whether alone or in. contact with a dissimilar metal. Contact with the titanium metals caused aluminum and magnesium to corrode by galvanic action. Coupling with stainless steel in sulfuric acid solutions decreased the normal corrosion rate of the titanium metals. Contact with aluminum in air-aerated oxalic acid and 0.1N sulfuric acid solutions resulted in cathodic corrosion of titanium and the titanium-base alloys; however, there were a few exceptions. The copper alloys showed better corrosion characteristics than titanium in certain sulfuric acid solutions but were more susceptible to chemical attack in some hydrochloric acid solutions.

Jan 1, 1958

By D. E. Wolfson

As a part of its overall program of coal carbonization, the Bureau of Mines is studying the coking properties of coals that may be used for metallurgical purposes. The objectives of this study were given in detail in a previous report.2/ The inherent suitability of coal for metallurgical use depends primarily on (1) chemical composition, (2) preparation characteristics, and (3) carbonization behavior. The first two factors, as well as the available reserves, are considered in selecting coals for carbonization tests. According to the estimate of reserves by Dowd,3/ the recoverable coal in Floyd County in beds 28 inches or more thick, in thousand tons, is as follows: [ ]

Jan 1, 1958

By G. Bhat, J. F. Libsch

A STUDY of the kinetics of embrittlement in engineering alloy steels during tempering has indicated that the presence of alloying elements may define two distinct regions of embrittlement: 1) at 800° to 1000 °F, termed low temperature embrittle-ment, and 2) in the temperature range 1150 ° to 1250°F, termed high temperature embrittlement.13 It has been suggested that embrittlement in each region may be due to a different mechanism. At intermediate temperatures and extended times the course of embrittlement may be influenced by the superposition of the embrittlement occurring in the two regions. Furthermore, low temperature embrittlement has been known to decrease as the temperature is raised slightly above the maximum embrittlement range.' Jaffe and BuffumV ave presented data for a Ni-Cr steel illustrating the removal of the em-brittlement occurring at 932°F by reheating to 1250°F for an hour. Their data further shows that embrittlement proceeds continuously with increased time at 1250°F, becoming pronounced at long times. They interpreted this behavior as a retrogression phenomenon involving the solution of the small nuclei of precipitate formed at 932°F as the temperature was increased, and reprecipitation of larger nuclei stable at 1250°F, with the reoccurrence of embrittlement. It appears desirable to reconsider this explanation in the light of the two regions of embrittlement proposed by the authors1 for some alloy steels. In addition, it appears desirable to determine any influence of a preconditioning treatment in each temperature range upon subsequent development of low and high temperature embrittlement. It is thus the object of this investigation to study the characteristics of the two modes of embrittlement proposed in a commercial Ni-Cr alloy steel (AISI 3140). Experimental Details Material—The material used in this investigation was commercial AISI 3140 steel bar stock, received as % in. hot-rolled rounds. The steel analysis was as follows (in percentages): C, 0.39; Mn, 0.79; Si, 0.30; S, 0.028; P, 0.015; Ni, 1.26; and Cr, 0.77. Material Processing and Heat Treatment—The bar stock was first ground to 0.430 in. squares and cut into specimens 23/4 in. long. These specimens were austenitized at 1650°F for 1 hr and oil

Jan 1, 1958

By F. G. Jaicks

RECOGNITION of the benefits to be gained from the continuous casting of molten steel into finished or semifinished products has been given by scientific minds since the very beginnings of steel plant technology. In fact, Sir Henry Bessemer is credited with the first of a long list of patents' issued by the U. S. Patent Office for a process which would accomplish this desirable end. None of these early ideas attained practical success and, as a result, the conventional method of teeming into ingot molds became an integral part of modern steelmaking operations. This procedure, although refined to keep pace with the changes which have come about in steelmaking and finishing facilities, is recognized to have inherent shortcomings which adversely affect manufacturing costs and steel quality. Interest in the continuous casting of steel persists because the process is directed toward avoiding some obvious weaknesses of conventional ingot casting. It has been recognized that should it be possible to substitute any of the continuous casting techniques under current development for ingot casting, it would no longer be necessary to make large capital investments in primary rolling equipment, the sole purpose of which is to reduce ingot castings to a form rollable on finishing mills. The results reported in the continuous casting of non-ferrous metals and specialty steels indicate that in addition to avoiding the primary rolling mills there is some basis for expecting significant improvements in yield, surface, and internal quality. Recognizing the shortcomings of the conventional procedures, the Inland Steel Co., in cooperation with Atlas Steels Ltd. and the Freyn Dept. of the Kop- pers Co. Inc., embarked upon a program to evaluate certain aspects of continuous casting in order to determine whether the process could be applied practically to an existing integrated steel plant producing 'large tonnages of carbon steels. TO assist in this evaluation a study was carried out in which several types of low carbon steel were continuously cast in an existing machine. It is the purpose of this paper to review some of the results obtained in the casting studies and to interpret the information that was obtained so as to indicate factors that must be considered in assessing operating limitations and plant capacities. Despite the early interest in the continuous casting of steel, the actual application to the steel industry is relatively recent. At present, there are about 25 operating plants casting steel, most of which have been built in the past decade. None of these plants could be classified as large in terms of the tonnages that are being processed by the major integrated steel plants. In contrast to the situation in the steel industry, there has been widespread adoption of the continuous process in the casting of nonferrous alloys, particularly aluminum and copper. As a result, much of the basic information that was required to apply the process to steel was developed in the nonferrous industries. In this respect, a most important contribution was the development of the Junghans2 system, which was initially designed for the casting of nonferrous metals and later applied to the casting of steel. Alternative methods for casting have also been proposed by Babcock and Wilcox Tube Co.,'" the British Iron and Steel Research Association,5 and the Gebruder Bohler A. G.13 Each of these methods is now being used successfully for the casting of special steels in small experimental plants or in modest sized commercial steelworks. The Original Junghans process was first developcd in Germany. Further application of the process has been made by Rossi in other countries.'*' The experi-

Jan 1, 1958

By Paul T. Allsman

THIS CHAPTER reviews the highlights of developments in mining technology during 1956 and presents a special report on the design of mine openings in stable ground. This special report is presented each year in an endeavor to stimulate use of the scientific approach to the solution of problems related to mining technology. Assuming that the literature on mining technology reflects trends in mining, it appears that two areas of activity were given most attention in 1956. One was research on mining technology,4 and the other was improvement of transportation, particularly trackless transportation, both at surface and underground mines.

Jan 1, 1958

By W. F. Carew, F. A. Crossley

IT has been reported that the Ti-8 pct A1 alloy is ductile as water quenched from 800°C but brittle as annealed at 650 °C." The present, somewhat limited, investigation was undertaken to discover the cause of the embrittlement. In order to evaluate to some extent the continuity of the embrittling phenomenon, alloys of 6, 8, and 10 pct A1 were studied. Subsequent to the completion of most of this work, Ence and Margolin reported that a Ti,A1 phase exists and that two or more unidentified compounds may exist in the Ti-A1 system.' Materials, Equipment, and Techniques The alloys were prepared using Kroll process sponge of 124 Bhn hardness. In addition, some 8 pct A1 material was made with iodide titanium. The sponge-base alloys were prepared as melts of 4 lb or more by double arc melting. The iodide Ti-8 pct A1 alloy was prepared as 200-g buttons. The alloys were forged at temperatures of 980" to 1150°C. Results of chemical analyses are given in Table I. A Baldwin-Southwark 60,000-lb capacity tensile machine, equipped with an autographic stress-strain recorder, was used for the tensile tests. Standard tensile test specimens, 0.252 in. diam, were used. Standard Charwy V-notch impact specimens were tested using a -kiehle machine. specimens were sealed in evacuated Vycor bulbs for heat treatment. Powder samples for Debye-Sherrer anal- ysis were prepared by filing and screening through 325 mesh. The —325 mesh fraction was taken in an effort to concentrate a microstructural constituent assumed to be less ductile than the a phase. The powder samples were stress relieve2 by annealing

Jan 1, 1958

By E. C. Perkins

This report describes a ferric chloride trap, based on formation of a low-melting sodium chloride-ferric chloride mixture of near-eutectic composition, and its use in chlorination of impure titaniferous materials. The trap is placed in the hot gas stream between the chlorination reactor and the condenser. Virtually all of the iron is removed by the trap. The condensed titanium tetrachloride is free of suspended solids and contains only a trace of iron. Four examples are given of the use of the ferric chloride trap in chlorination of impure titaniferous materials. INTRODUCTION In the Kroll process, ductile titanium metal is produced by reducing titanium tetrachloride with magnesium metal.4/ In commercial practice, titanium tetrachloride is produced by chlorinating titaniferous materials in the presence of carbon.2/ In 1957 most producers were using rutile, and virtually all plants were designed for its use. About four-fifths of the domestic consumption of rutile was imported from Australia. The Bureau of Mines, under provisions of contract DMP-116 with the General Services Administration, studied electrosmelting of domestic ilmenites and titaniferous magnetites to produce high-titanium slags with pig iron as a byproduct. Under the same contract, chlorination studies also were being made of these slags. Smelting was done at the Northwest Electrodevelopment Experiment Station, Albany, Oreg., and chlorination at the Electrometallurgical Experiment Station, Boulder City, Nev.

Jan 1, 1958

By H. Kenworthy

The objective of this investigation was to evaluate the technical feasibility of smelting certain low-grade domestic iron ores in an electric furnace. Laboratory-scale experiments showed that a high recovery of iron in the form of pig iron can be obtained from east Texas ores containing less than 25 percent iron. The pig iron was amenable to standard-or electric-furnace-refining methods for producing steel. Car-bon, silicon, and phosphorus were the primary impurities removed in refining. Overall recoveries of iron as pig iron exceeded 95 percent, in contrast with commercial mineral-dressing recoveries on these particular ores of 50 percent of the iron as a 45-to 50-percent iron concentrate.

Jan 1, 1958

By Eugene T. Sheridan

The annual survey of the fuel-briquet industry by the Bureau of Mines, United States Department of the Interior, revealed that 21 fuel-briquet plants in 11 States were in operation and reported production in 1956. The demand for fuel briquets in the United States has gradually declined since 1948, and the number of operating plants has decreased from 36 to 21. Also, the annual productive capacity of the industry has decreased, although not a proportionate amount because most of the plants that were abandoned were small and in most instances had a designed capacity of less than 25,000 tons per year. In 1956 the 21 active plants had an annual capacity of 3.7 million tons (table 2), which was only 20 percent less than the total capacity of the 36 plants in 1948. This indicates that most of the larger plants have remained active, even though operating at reduced rates, and the average capacity of the industry has increased from 130,000 tons per plant in 1948 to 177,000 tons in 1956. Since 1948 operating rates have decreased from 67 percent to 41 percent of annual capacity.

Jan 1, 1958

By Robert L. Mentch

CADMIUM is one of the metals apparently destined to remain relatively scarce. The en tire supply of primary cadmium is recovered as a byproduct, concurrently with the treatment of ores of other metals. Development of the cadmium industry is attributed to metallurgical improvements in the zinc industry; output depends almost wholly upon zinc production. Cadmium is a metal of specialized uses where its superior performance has developed a strong, expanding demand. The supply, however, has been relatively unresponsive to price because of its byproduct nature. Cadmium's outstanding properties would assure it a manyfold greater market if more were available at lower prices.

Jan 1, 1958

By Oliver Bowles

The Bureau of Mines issued three Information Circulars on marble many years ago (5), (6), (7).2/ They have long been out of print; furthermore, conditions have changed considerably in the industry in succeeding years. A presentation of current data is therefore desirable. This report furnishes general information on marble, including its properties, distribution of domestic and foreign deposits, methods and equipment used in quarrying and milling, economic and marketing problems, and recent advances in marble technology. INTRODUCTION Most marbles are crystallized limestone. The term "marble" is derived from a Greek word meaning to sparkle or flash, because the calcite crystals in marble sparkle as they reflect light. The word "marble" is employed frequently to mean a small ball used in the game of marbles with which nearly every child is familiar. Although the little spheres were originally of marble, few of those made in recent years contain that material; nevertheless, the expression "playing marbles" has persisted.

Jan 1, 1958

By Frank L. Wideman

This information circular describes methods used in mining inclined beds of phosphate rock in mines operated by San Francisco Chemical Co. in Rich County, Utah. The mines are on the western flank of the Crawford Mountains, a short, narrow range in northern Utah near the Idaho-Wyoming corner (fig. 1). The western front of the range is a conspicuous wall of folded and faulted sedimentary rocks that rises abruptly 300 to 600 feet above the floor of the adjacent Bear River Valley. Rex Peak, highest point in the range, is approximately 8,000 feet above sea level. The area surrounding the mines is sparsely populated. Randolph, the county seat of Rich County, has a population of 650. It is 10 miles southwest of the mines by road and the only town in their vicinity.

Jan 1, 1958

By James Westfield

A brief résumé follows of recent activities of the Division of Coal-Mine Inspection that have had a favorable effect on health, safety, and the reduction of injuries at coal mines: 1. The Federal Mine Safety Code for Bituminous Coal and Lignite Mines of the United States was issued originally by the Director of the Bureau of Mines on July 24, 1946, after consulting with management and labor representatives of the coal-mining industry. The code has been used by Federal coal-mine inspectors while inspecting bituminous-coal and lignite mines as a basis for determining the existence of unhealthful and unsafe conditions and practices in these mines. A revised code was issued by the Secretary of the Interior on October 8, 1953, after further consultations with representatives of management and mine workers and was incorporated by reference in the 1952 and subsequent bituminous-coal wage agreements. The agreement of May 29, 1946, between the Secretary of the Interior, acting as Coal Mines Administrator under authority of Executive Order 9728, and the United Mine Workers of America, covering bituminous-coal and lignite mines in Government possession, charged Federal coal-mine inspectors with the responsibility of making periodic investigations of the mines and reporting to the Coal Mines Administrator any violations of the Federal Mine Safety Code. Federal coal-mine inspectors also had temporary authority to close mines found to be imminently dangerous, but such authority (under Executive Order 9728) was removed on June 30, 1947, when Government control of the mines was terminated.

Jan 1, 1958

By Woodcock J. T

When an aqueous suspension of pyrite and manganese ore reacts with oxygen, manganese is dissolved by the ferrous sulphate and sulphuric acid produced by the oxidation of pyrite. The kinetics of certain steps in the overall reaction were studied. A rate equation for the oxidation of ferrous sulphate by gaseous oxygen was derived for the temperature range from 1000 to 200° C. An exact rate equation for the production of ferrous ion from pyrite could not be established but it was shown that the temperature, oxygen pressure, pyrite surface area, and the reduction of ferric ion by pyrite are important. A rate equation was derived for the reaction of manganese dioxide with ferrous sulphate. A major facfor controlling the rate was whether or not ferric oxide was formed by hydrolysis at the manganese dioxide surface.It was shown that if hydrolysis was prevented the factor cpntrolling the rate of the overall reaction ,was the rate of production of ferrous ion, and little ferrous ion was oxidised by oxygen. When hydrolysis of iron did occur, the overall rate was not a simplefunction of anyone factor and much ferrous ion was wasted by oxidation with oxygen.INTRODUCTIONIn another paper (Cornelius and Woodcock, 1958) the results of the reaction of an aqueous suspension of a manganese ore and pyrite with oxygen are reported. It is shown that the ferrous ion and sulphuric acid generated in situ by the oxidation of pyrite, dissolves manganese as manganous sulphate. To obtain a better understanding of the process as a whole, the kinetics of certain steps in the overall reaction were studied.When an aqueous suspension of a manganese ore and pyrite reacts with oxygen, the overall reaction may be conventionally represented by equation (1) (Cornelius and Woodcock, 1958).2Mn02 + 2FeSz + 6i02 + 2HzO= 2MnS04 + 2H2S04+ F'ez03 ... , .. (1)

Jan 1, 1958

By C. E. Henning

The total number of petroleum refineries in the United States on January 1, 1958, was 318 and their total crude-oil throughput capacity was 9,407,707 barrels per day, according to the Bureau of Mines annual survey. During 1957, 3 new refineries began operating while 4 refineries were retired. Although there was 1 less refinery, the total crude-oil throughput capacity at the beginning of 1958 was 284,033 barrels per day, or 3 percent, more than the January 1, 1957, level. During 1957 all refinery districts showed increases in capacity. The largest increase, 27 percent, occurred in the West Coast district followed by the Indiana-Illinois-Kentucky district with 14-percent increase and the Texas Gulf Coast district with 13-percent increase. The national increase in capacity had the effect of raising the capacity of the average refinery from 28,601 to 29,584 barrels per day. New crude-oil capacity under construction on January 1, 1958, totaled 185,265 barrels, and an additional 297,885 barrels capacity was reported building as replacement for existing facilities. Included in total new construction were 2 new refineries, 1 in Washington and another in Texas, with planned processing capacities of 45,000 barrels and 8,550 barrels per day, respectively.

Jan 1, 1958

By J. F. Davis

Pegmatite dykes containing lithium minerals and beryl occur dose to the borders of intrusive masses of granitic rock in the Winnipeg River area of Manitoba. Both vertical and flat-lying dykes are present. Most of the pegmatites consist of zones, containing characteristic mineral assemblages, arranged more or Jess parallel to the borders of the dykes. Five important lithium minerals are present; each occurs in a separate zone, but all the lithium-bearing zones are situated toward the centres of the pegmatites. Spodumene is the most abundant and widespread of the lithium minerals and occurs as small crystals intimately intergrown with quartz. Beryl is not an important constituent of the lithium pegmatites, but when .present, occurs outside the lithium zones, toward the margins of the -dykes. Beryl is most common in dykes containing few or no lithium minerals. The mineral assemblage in the beryl zone of the lithium dykes is the same as that of the beryl dykes. The attitude and internal structure, particularly zoning, of the pegmatite dykes, and the texture and assemblages of the constituent minerals, have an important bearing on exploration, development, and mining of these pegmatites, and on the extraction of various mineral products from them.

Jan 1, 1958

By W. Vickers

SALKOVITZ1 has given a number of useful angles between planes for use with the Laue method in determining the orientation of bismuth single crystals. Bismuth is usually considered as having a face-centered-rhombohedra1 structure with its axial angle 87°34', Fig. 1. A similar figure given by Sal-kovitz appears to be in error in that the angle there marked as 87°34' should be 92°26. The primitive cell is a single rhombohedron of axial angle 570 14. The structure is almost face-centered-cubic and hence high accuracy in measurements is essential if there is to be no confusion in indexing poles or zone axes. It is easier to get this accuracy if zone axes are plotted on the stereogram because they will lie near the basic circle where the net has a more open scale. The zone axes can be read from the film, using a Greninger chart, and can be plotted more accurately than poles. Also, the angles between points near the basic circle can be read more accurately than those between poles near the center. In order to use the zone axes the angles between directions have been calculated from a formula given by Niggli,2 and are given in Table I. Miller indices

Jan 1, 1958

By Ervin E. Underwood

IT has been recognized for many years that dis-persed particles have great value in raising the creep resistance of metallic alloys. In fact, some of the most successful high-temperature alloys owe their superiority to this factor above all others. A recent observation by Glen1," indicates that even better high-temperature resistance to deformation results in alloys capable of two successive precipitation reactions. The ramifications of this finding are of great interest. Unfortunately, our understanding of the reasons for such notable improvements has not kept pace with technical developments. In an effort to uncover some of the basic facts governing strengthening by particles, a program was initiated at the Battelle Memorial Institute with the primary goal of comparing creep strengths in single-phase and two-phase (precipitating) alloys. The effects of precipitation from solid solution on the creep properties of alloys are generally such that the resistance to creep is increased. However, if alloys are heat treated to different degrees of hardness before creep testing, it is often found that those possessing the maximum hardness initially do not necessarily have the maximum creep resistance. Depending on the stresses and temperatures involved other structures may prove more desirable. Considerations of the above nature indicate the importance of defining the initial state of the alloy. Here, it was decided to start with quenched single- phase alloys in which precipitation and creep deformation proceed concurrently. Equipment and Experimental Procedures Preparation of the Specimens—Four 25 lb ingots were prepared from 99.999 pct Cu and 99.996 pct Al to compositions of 1, 2, 3, and 4 wt pct Cu. Spec-trographic and chemical analyses are listed in Table I. After heat treatments and intermediate reductions, the alloys were cold rolled to 1/8 in. thick sheet. The final cold reductions amounted to 50, 40, 20, and 10 pct for the 1, 2, 3, and 4 pct Cu alloys, respectively. The specimens for creep testing were machined into tensile flats 7 in. long, 3/4 in. wide (at the shoulders), and 1/8 in. thick. The reduced sections were 1/4 in. wide and 21/2 in. long. After heat treatments at 540°C to an ASTM grain size of 1 1, the specimens were quenched into water at room temperature, then electropolished in a glacial acetic acid and perchloric acid solution. The gage marks were Knoop impressions placed 2 in. apart on the reduced sections. Blanks of 1 x 1 in, were cut from the same sheets for the age hardening runs and were given the same grain size heat treatments. The specimens and blanks were stored in a refrigerator at —40°C until needed for testing. Creep Measurements—Creep tests were conducted in a constant temperature room which was maintained at 26° ±1°C. A split-type, hinged, vertical-tube furnace was mounted on a horizontal track so that the specimen could be enclosed suddenly. Thus, it took about 15 min for the specimen to come within 5°C of the test temperature. The temperature variation along the specimen was controlled to about

Jan 1, 1958

By R. J. Grace

Carbon in the form of coke is used as a reactant in various chemical and metallurgical processes, The high cost of by-product coke along with its periodic lack of availability and high investment necessary for additional by-product recovery facilities indicate the need for a low-cost production unit based on a new procedure for coke manufacture, Traveling-grate coking-stokers were developed by Shawinigan Chemicals Ltd. to produce coke required for carbide manufacture, They were adapted to kilns so that the hot volatile gases could be used for lime burning, Their operation has been described in various patent disclosures (1, 2, 3), and their application to rotary lime burning kilns has been described by Andersen (4). Details of the process and plants have also been published by Kurt Baum (5,6).

Jan 1, 1958