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By George Anagnostache

AMONG the petroleum-producing countries of the world, Roumania occupies the fifth place; in Europe, it occupies second place, coming after Russia. The extraction and the use of petroleum in Roumania, may be trace( as far back as 1856, but the production on an industrial scale started in 1896, when the "Steaua Romana," was formed. From that time until the beginning of the war, the petroleum industry had a rapid growth the number of the producing companies increased to 37, and production FIG. 1.-ROUMANIAN OIL AND GAS FIELDS. increased from 81,571 tons, in 1896, to 1,898,545 tons, in 1912, when the greatest production was reached. In 1916, when the Germans invaded Roumania, the oilfields, at the order of the Allies and under British supervision, were destroyed, to pre vent their exploitation by the Central Powers; the wells were blown in the refineries and the storage tanks burnt, and pipelines put out of order This voluntary destruction, which weakened the resistance of the Central Powers, set back the petroleum industry at least one decade. Reconstruction after the war was slow, because of bad transportation conditions the scarcity of drilling and refining material, the insufficiency of. electric power, and the continuous depreciation of the Roumanian money, which made difficult the buying of the necessary materials for reconstruction.

Jan 3, 1925

By Frank Gilbreth

THE problem, of the crippled soldier in industry is not a problem of war work only; it is a problem of industrial development. As individuals, each one of you is seeking to provide our maimed heroes with such teaching as will render them, in the shortest possible amount of time, productive and satisfied members of the community. As individuals you are interested in the organizations that are preparing to receive these men, to train them and to place them at that work for which they are best fitted. As an organization, it is now your duty to take up the industrial end of the problem, to investigate existing conditions in the industries, to discover where the opportunities for employment lie, and so readjust industrial practice that the cripples may be utilized to their own and the community's good with the least shock to themselves or to the industries, and with the greatest amount of permanent benefit to all concerned. We have divided industrial opportunities suitable for cripples roughly, into three classes. First, such as already exist in the industries, which can be set aside for cripples only, present occupants being transferred to other work for which they can be fitted but which is not suitable for cripple work; second, opportunities in the industrial world that, through changes in the working equipment or tools, or through appliances attached to the cripple himself, can make the cripple a competitor of the sound worker; third, opportunities not existing at present in the industries, but which could be introduced for the good of the community, without placing the cripples into competition with any existing class of workers.

Jan 4, 1918

By Edwin Hopkins

The year of 1924, in Venezuela, has been one of especial interest. The figures for production marketed are not so impressive, but to the well-informed followers of the development, the ease with which this production has been obtained and with which it apparently can be increased at will merits most careful consideration. For several years, the oil world, especially in the financial centers, has been closely following the slow unfolding. of the' Venezuelan developments, which has been, and still is, one of the great pioneering achievements in the history of oil exploitation. Venezuela, from the first days of its recognition by geologists and financiers as a great future source of oil, has been a field for the enterprising vision of the larger capital groups. The laws of the country have been drafted with almost an inspired foresightedness that has favored the exploitation of the resources along constructive lines, which' has eliminated the irrational promotion schemes that accompany many of the oil developments in the United States. Developments have been exclusively in the hands of strong financial groups, who have followed a conservative policy with respect to the dissemination of detailed information concerning the geological findings and detailed production data. Within the last year, however, the rapid expansion of the production phase of the developments has been on such an important scale and has involved such a large and rapidly increasing personnel, that further restraint with respect to information of a general informative' nature can serve no useful purpose. Certainly, from the volume of references to Venezuelan oil affairs, which are now of almost weekly occurrence in the oil trade journals, the public must appreciate the fact that in Venezuela, and in the Maracaibo district in particular, a new oil region of the first magnitude is about to emerge from comparative obscurity and occupy a commanding position on the stage of world oil affairs.

Jan 3, 1925

By H. S. George

A method of illumination that enhances the value of microscopic study of opaque materials, as in metallography. By simulating natural lighting, structures. That possess relief are given a natural appearance. An example is included of the revelation of a hitherto invisible microconstituent. Erroneous interpretation is avoided. For example, etching figures in ferrite, heretofore considered to be pits, are revealed as pyramids, standing in bas-relief. Suggestions on technique are given, for, while the method is obvious, practice and attention to detail are requisite. ON one occasion when it seemed desirable to reveal under the microscope not only the metallic structure of an alloy, but certain small non-metallic inclusions, that are ordinarily obliterated by etching, it was discovered that, by partly eclipsing the illuminating pencil of light rays, the residual light was thrown on the object from one side and the structure was brought out in relief. At the same time, the non-metallic inclusions were retained in clear view. In this first demonstration of lighting obliquely through the objective a card was thrust part way into the light beam between the arc iris, and the light filter; the shadow of the card on the filter served to locate its position. Next several stiff-paper disks of various diameters were mounted on flexible wires some plasticine on the other end of the wires made it easy to adjust and maintain a disk at any desired position in the light beam. To facilitate manipulation, an assortment of disks, was mounted on a wheel, as shown in Fig. 1. The purpose of partly eclipsing the light beam was discussed in an earlier paper.1 There it was pointed out that the usual methods of illuminating opaque objects for microscopic examination lend an, un-natural appearance to, the view, while the new method, which has been termed conical illumination, revels the true relationship of constituents by simulating natural lighting.

Jan 3, 1924

By J. B. Mudd

Introduction It is difficult to think of any activity on which mankind has been more dependent than mining, and certainly there is much evidence in almost every part of the world of old workings that clearly demonstrate that man from earliest times has dug and toiled to take from the earth precious stones, metals and materials that from time to time have been essential or of value to him. In step with social development and industrial and technological advances the tempo of mining activity, regulated only by the laws of supply and demand, has quickened and in this century has accelerated rapidly in keeping with its dramatic development. Indeed, the rate of change of events has been such that if it were to continue to accelerate as fast as it has over the past decade there is reason to wonder how the insatiable demands for metals and minerals are to be met in the years that lie ahead. Shallow mines containing high-grade ore deposits either have been or are being rapidly mined out and their place can only be taken in general by ore lying at greater depth, or by ore of low grade, situated for the most part in remote and in underdeveloped areas. The cost of exploration and development is rising at an alarming rate, with the result that the expenditure now required to bring a mine to production far exceeds anything previously contemplated. It is estimated that the total capital required to maintain existing operations and develop new ones during the next 5 years will be of the order of $50,000 million and of this, new capital to bring new mines to production will be of the order of $3,000 million. Today no single mining finance company can, from its own resources, find all the money for a major mining development, and as a consequence there has been a strong trend toward joint ventures and to the formation of multinational consortiums. International lending institutions already play an important part in financing many new mining projects and their participation provides the financial umbrella under which other lenders can invest with greater security. There is little doubt that to finance the costly ventures in the future, governments and international lending agencies, banks and finance

Jan 1, 1971

By Archer E., Wheeler

COPPER operations in the Congo mean the operations of the Union Miniere du Haut Katanga, because there are no other copper industries there. There is a mine at Bwana M'Kubwa, a little way to the South, in Rhodesia, which has been operated on a small scale, and-another farther south, the Falcon mine, but in quite a different section of the country. This Bwana M'Kubwa mine has recently been reorganized financially and the Minerals Separation interests have taken an extensive share in it, so that it may come into operation. The Union Miniere's operations are in Katanga, the most southeastern province of the Belgian Congo, and the company's concession is in the southeastern part of that province. The usual route for going into the country is by way of Cape Town, thence over the South African Railways through Kimberly and Mafe- king to Bulawayo, then by the Beira, Mashonland and Rhodesia Railways to the Rhodesia-Congo border, passing Victoria Falls on the way, and finally by the Belgian road, the Chemin de Fer du Katanga, to Elisa- bethville, the African headquarters of the company. From Cape Town to the border it is about 2150 mi. and from the border to Elisabethville about 158 mi., making a little over 2300 mi. from Cape Town, by rail.

Jan 1, 1924

By S. W. Parr

FROM a study of sulfur with reference to its specific combination in coal, published as University of Illinois Bulletin No. 111, 1919, it is now possible to determine the various forms of this constituent with a good degree of accuracy. This fact suggests two questions: (1) Are the same analytic methods applicable to coke? (2) Is there any correlation between the forms of sulfur as it occurs in coal and the residual sulfur found in the finished coke? The answer to the second question might be helpful in answering a still further question as to what chemical route the sulfur travels during the carbonization process. While the special studies along these several lines are by no means complete, a few preliminary statements are herewith presented. They may, at least, prove suggestive of further possibilities from a continuation of research along these lines. There is no reason, chemically, why the analytic methods devised for coal should not apply to coke and a fair amount of experience in connection with such use affords confirmation of this statement. The procedure in the case of coal may be briefly outlined as follows; Combinations of sulfur as sulfate, or sulfides other than FeS2, are readily dissolved without disturbing either the pyrite sulfur or the sulfur that is in organic combination by means of dilute hydrochloric, acid-1 part of concentrated HC1 to 10 parts of water or approximately 3 per cent. acid. Digestion at 60° C. for 24 hr. insures the complete removal of the sulfur thus combined. In freshly mined coal the amount of such sulfur is very small; weathering processes, however, may very materially increase the amount of sulfate present.

Jan 9, 1919

By N. S. Wagner

The production of lightweight aggregates in Oregon is a new industry, and, like all new enterprises, it is suffering from growing pains characterized by numerous, small operations some of which flourish for a short time and then cease altogether. Normally all industrial mineral products are produced in a highly competitive atmosphere. At the present time this condition does not exist to a very marked degree in the state because as yet producers have not saturated the constantly expanding market. This paper has been prepared with the intention of outlining very briefly the current status of the various products now being used as lightweight aggregates in Oregon. The present picture will surely change, perhaps quite radically within even a short space of time.

Jan 1, 1949

By FORTUNATO PEREIRA

(San Francisco Meeting, October, 1911.) I. GENERAL DESCRIPTION. The Department of Narino (formerly included in the Department of Cauca) is a narrow band about 170 km. (100 miles) wide in the southern part of the Republic of Colombia, FIG. 1.-SKETCH-MAP OF THE SOUTHWESTERN PART OF COLOMBIA. near the boundary of Ecuador, as shown in the sketch-map, Fig. 1. Its capital is Pasto, a small city of 25,000 inhabitants; the principal towns are Túquerres, Cumbal, Ypiales, Barbacoas, and Tumaco. The port on the Pacific ocean is Tumaco, and traffic in the interior is carried partly on the Patia river (steam navigation to the fluvial port of Barbacoas), and afterwards overland over poor roads by human bearers or on mule-back.

Aug 1, 1912

By William P. Blake

The occurrence of the manganiferous variety of wolframite at a new locality in Arizona was announced in the month of May last." It occurs in the granite hills of the Dragoon mountains, in Cochise county, about 6 miles north of Dragoon Summit station, on the Southern Pacific Railway of Arizona. It is found in veins of white quartz, traversing a coarsely crystalline granitic gneiss, and, so far as yet determined, is without association with other metallic minerals in the same veins, except small quantities of scheelite. It is a very pure form of the mineral, and contains but little iron, the base being manganese oxide. The color is brownish-red; it is nearly the same as the color of the mineral originally described by E. Riotte from Mammoth District, Nevada.† Thin films or plates on the broad cleavage-surfaces, and thin cleavage-flakes, seen by transmitted light, are ruby-red, or rather more like the color of red zinc oxide or the mineral known as clintonite. By long-continued weathering the surface becomes less deeply colored, and assumes a bronze-like luster, like the dull oxidized surface of

Jan 1, 1899

By C. V. Millikan

TEMPERATURE measurement in wells is an old practice and geothermal gradients have been of interest to geologists for many years.1,2 Their application to the operation of oil wells is a more recent practice. It has long been recognized that temperature anomalies occur in drilling and producing wells but thermometers that could obtain a satisfactory record of the anomalies were not available.3 The normal geothermal gradient is con-sidered as being about one degree Fahren-heit for each 60 ft. of depth.4 This "nor-mal" gradient varies in different areas, but whatever it may be in an area there is little variation from the surface to as deep as the drill penetrates. The normal gradient is appreciably changed by gas expanding from the reservoir into the borehole or by the movement of fluid through a borehole while drilling, producing, or circulating. It is the resulting anomalies and abnormal gradients from which conditions in wells can be interpreted. Some of the applications of such interpretations are locating the position of oil or gas sands, permeable strata in a reservoir zone, gas-oil contact, source of water, casing leaks, and the top of cement behind casing.

Jan 1, 1940

By AIME AIME

A STUDY of subsidence and ground movement in the copper and iron mines of the upper peninsula of Michigan has been made by W. R. Crane of the United States Bureau of Mines and published as Bulletin 295 of 66 pages and 49 illustrations. As a result of subsidence, the country adjacent to the mines and over- lying the mine workings in this district is often broken to such an extent as to affect its value; mine shafts and development openings are occasionally so damaged as to be rendered useless, and water can enter the workings through fractures and cave-ins. The problem is more serious in the iron-mining districts, where villages and towns not owned by the operating companies have grown up around mining operations.

Jan 1, 1929

All the TECHNICAL PUBLICATIONS and CONTRIBUTIONS published in 1939 are available at Institute headquarters, unless otherwise noted. They are also on file in many public, university and technical libraries and, when so indicated in the list, may be found in the TRANSACTIONS. TECHNICAL PUBLICATIONS in Classes A-Metal Mining, B-Milling and Concen-tration, H-Industrial Minerals, and ;I-Mining Geology are distributed in MINING TECHNOLOGY, which is issued every other month. Technical Publications in Classes C-Iron. and Steel Division, D-Nonferrous Metallurgy and E-Institute of Metals Division are distributed in METALS TECHNOLOGY, which is issued twice quarterly. TECHNICAL PUBLICATIONS in Class G-Petroleum Division are distributed in PETRO-LEUM TECHNOLOGY, which is issued quarterly. TECHNICAL PUBLICATIONS in Classes F-Coal Division, J-Mineral Industry Education Division, K-Mining Administra-tion, and L-Geophysical Methods of Exploration are issued as separate pamphlets. An Institute member is entitled to one copy of any TECHNICAL PUBLICATION or CON-TRIBUTION. Copies of TECHNICAL PUBLICATIONS listed have been mailed to members of the Institute according to their registration by classes. CONTRIBUTIONS and Other TECHNICAL PUBLICATIONS will be sent upon request. A member relay purchase an additional copy of a TECHNICAL PUBLICATION Or a CONTRIBUTION at One cent a page; minimum charge, 25¢. Nonmembers may purchase any CONTRIBUTION or a TECHNICAL PUBLICATION Of the F, J, K, or L classes at the same rate, but the nonmember price per copy for METALS TECHNOLOGY, MINING TECHNOLOGY or PETROLEUM TECHNOLOGY is $1. TECHNICAL PUBLICATIONS (separate pamphlet form), $2 per annum; Canadian and foreign postage 50 cents extra. METALS TECHNOLOGY, $7 per annum; Canadian and foreign postage 50 cents extra (Iron and Steel Division and Institute of Metals Division ferrous and nonferrous papers). MINING TECHNOLOGY, $6 per annum; Canadian and foreign postage 50 cents extra (metal mining, milling and concentration, Industrial Minerals Division, and mining geology papers). PETROLEUM TECHNOLOGY, $4 per annum; Canadian and foreign postage 50 cents extra. Bound volumes have been mailed to members that have requested them, and MINING AND METALLURGY is mailed each month. A member is entitled to one volume a year on his membership and lie may purchase for $2.50 one copy of a volume not already received; additional copies of 'the same volume, $5. Nonmembers may pur-chase the volumes listed, at $5 each, plus 60 cents for Canadian or foreign postage. Extra single copies of MINING AND METALLURGY, 25¢ current issue, back numbers 500 each to members; to nonmembers 50¢ current issue and $1 each, back issues. Subscription price to nonmembers and to members for extra copies, $3 per annum plus $1 for Canadian or foreign postage.

Jan 1, 1939

By Thomas Read

READJUSTMENT Of the industrial world to a peace .basis after more than 4 years of war will involve many fundamental and far-reaching changes that cannot as yet he clearly foreseen or definitely provided for. Such problems may be subdivided, in the vocabulary of war, into those involving material and those centering about personnel. Of the two, the-latter group is the more difficult and obscure, as the factors involved are less clearly understood and the methods to be followed are not yet tested and standardized. When it is said that the market is weak, stocks large, and demand light, every business man understands clearly what is meant and. what course he should adopt to adjust himself, so far as possible, to such conditions. But when it is said that the rapid spread of Bolshevism in Europe is a danger to industrial organization in this country, it is difficult to have any assured sense that all that the statement may mean is clearly understood or that the means to be followed to meet such a situation are definitely known. Since Bolshevism is primarily a mental phenomenon and since the rupture it brings about in industrial organization should be prevented, if possible, it is my purpose to restrict this discussion of the activities of the Committee on Industrial Organization to some of its mental aspects, as the chairmen of the sub-committees, from their special knowledge of their own fields, can best set forth recent progress in the lines with which they are especially concerned. The first requisites of success in industrial organization, as in the biological organism of which it is the social counterpart, are unity of purpose and coordinated activity. Typical good and bad examples of this are the relative parts that the United States and Russia have played in the great war. These two factors are primarily mental, and it is not difficult to view the mental aspects of all problems of industrial organization as the most important ones. Unless we can attain unity of purpose and coordinated activity in industry, the provision of comfortable homes at reasonable rent, the assurance of steady work at good wages, the

Jan 2, 1919

By Strathmore R. B. Cooke, Thomas E. Ban

MUCH experimental work has been performed on the mechanism of agglomeration and pelletizing of moist ore and concentrates and on the process of firing agglomerates, but except for the work of Tigerschiöld and Ilmoni1 much of the published information is empirical, and the literature contains no information concerning the structure of fired pellets. Results of a preliminary study of the microstructures occurring in pellets produced both in the laboratory and on a pilot-plant scale are presented in this paper. Most of the results were obtained from pellets prepared from Mesabi magnetic taconite, but through the courtesy of the staffs of the Minnesota Mines Experiment Station and the Bethlehem Steel Co., fired pellets produced from limonite and hematite ores and from Lebanon magnetite have also been examined. The work has been restricted almost entirely to pellets produced without additives, the exceptions being those in which coal was. added to the filter cake before rolling. Schwartz has described the microstructures occurring in ore sinters produced under reducing conditions.2 Many of the structures and constituents he describes are common to fired pellets, but the constituents normally occur in markedly different proportions. His statement that "in all satisfactory sinter the amount of hematite is small, perhaps not over 2 or 3 per cent" is inapplicable to pellets produced by pilot plant operation or by any process in which air is not deliberately excluded. Pilot plant pellets contain over 90 pct by weight of hematite, and those produced in the smaller furnaces of the Minnesota Mines Experiment Station contain more than 80 pct of that constituent. Preparation of Specimens It is difficult to examine unfired pellets microscopically because of their insufficient coherency to withstand sectioning and polishing. Fired pellets sometimes lack coherency and frequently contain holes which are troublesome during polishing. Impregnation of both air-dried and fired pellets is readily accomplished by the use of methyl methacrylate monomer.3 The dry pellets are covered in a test tube with excess monomer, to which a small amount of accelerator has been added. When the test tube is placed in a cooling bath and evacuated with an aspirator, most of the entrapped air is removed, and disruption of weak pellets by boiling of the monomer is reduced to a minimum. Polymerization is then effected by immersion of the test tube in a water-bath at about 45°C, this temperature being held for 4 or 5 days. The test tube may then be broken away from the solidified mass and the pellets sectioned by a carborundum wheel or a diamond saw. Where time is important, impregnation is carried out at a higher temperature by Meyer's method.4 Air-dried pellets must be impregnated with especial care; otherwise swelling occurs and the solids are displaced. It is more important to be certain that the monomer forms a reasonably complete network throughout the specimen than that all entrained air is removed, and for this reason the vacuum technique may be omitted. Impregnated agglomerated products and pellets are extremely coherent, section well, and may be polished either by hand or by machine. Hand polishing is not satisfactory for the examination of conditions existing at the boundaries of grains, and for this machine polishing must be used. The Graton-Vanderwilt machine gives excellent results, provided that pressure on the specimen is considerably in excess of that recommended by the manufacturer. Mineralogy of Fired Pellets Only two opaque iron minerals, magnetite and hematite, have been recognized in pellets. The complete identity of these artificial minerals with their corresponding natural counterparts is shown by their mineralographic characteristics and their X-ray structures. Wüstite has not been found. Slag is the most common transparent constituent of fired pellets. Occasionally conditions have been appropriate for the crystallization of fayalite from the slag, and at other times another crystalline sil-

Jan 1, 1952

By C. A. Edwards

Following a brief introduction, an outline is given of the four main conditions in which gases may be associated with metals; namely, (1) adsorbed gases, (2) dissolved gases, (3) gases in chemical combination, (4) gases entrapped in blowholes or cavities. Adsorption is essentially a surface phenomenon and is regarded as the attachment of outside molecules or atoms to the exposed free valencies of the atoms comprising the surface layers. In many cases where adsorbed films of gas are formed this is accompanied by a process of diffusion of the gas into the metal itself. This is particularly true in respect to iron and hydrogen, and experiments have shown that there is no difference between the rate at which hydrogen diffuses through a single crystal of iron arid through the same material after it has been recrystal-lized into a mass of small crystals. This does not prevent a somewhat greater concentration of gas at the boundaries of adjacent crystals, nor does it mean that the effect of the gas will be the same at the boundaries as it is within the body of the crystals. Indeed, under certain conditions, iron is rendered very brittle at the crystal boundaries, as shown in experiments by Pfeil with samples of almost pure iron. Much work has been done by many investigators concerning the temperature and conditions under which dissolved hydrogen, in particular, can be at least partially removed from different metals. With iron, the hydrogen that has diffused into the metal as a result of acid attack by pickling or by electrolytic deposition of the gas on the metal is partly removed by exposing the metal to the atmosphere at ordinary temperatures. Considerably more can be eliminated by raising the temperature, and even greater quantities by jointly raising the temperature and reducing the pressure. Annealing at suitable temperatures completely removes the bad effects of excessive mounts of hydrogen dissolved in or associated with iron. This is shown by the data plotted in Fig. 1, giving values for electrolytic iron sheets after annealing at temperatures between 250" and 950" C. The hydrogen brittleness is rapidly diminished at

Jan 1, 1935

By Leonard Greenburg, William B. Harris, Gustäv Werner

HAULAGE in tunneling operations generally has been done with electric locomotives. As a rule, on short hauls the source of electricity is a storage battery mounted on the locomotive, which, of course, must be removed and recharged periodically. Where the distance from the recharging point to the tunnel face is very long, and where loads are heavy, trolley-driven locomotives are used. Diesel engines have been used in mining and tunneling operations in Europe for a number of years. The recent reports of studies in Belgium1 and by the Bureau of Mines in this country2-4 have indicated the potentialities of this form of power for haulage, mucking, bulldozing and many other underground operations. The hazards attending the use of Diesel engines in more or less closed spaces have long been known. The exhaust constituents that may create a harmful or objectionable environment are carbon monoxide, oxides of nitrogen and sulphur, carbon dioxide, aldehydes and smoke. Lack of precise information regarding the concentration of these gases and the ventilation requirements to reduce them to safe levels has to some extent suppressed their general acceptance in tunneling and mining work. Not until the work of the Bureau of Mines referred to above, and certain experience gained in the construction of the Delaware Aqueduct,‡ has there been available the requisite information regarding the conditions under which their use may be permitted. This paper concerns itself with the successful operation of Diesel engines underground in the construction of certain parts of the Delaware Aqueduct, and describes the conditions under which Diesel engines have been found to operate with a minimum production of noxious gases. The test data reported were obtained during the operation of Diesel engines over a period of two years.* STUDIES BY THE NEW YORK STATE DEPARTMENT OF LABOR Exhaustive tests were made by the Division of Industrial Hygiene, of the composition of the exhaust gases given off by a Diesel engine mounted on. a test block. These tests showed that certain quantities of the gases are discharged from the exhaust. On the basis of these figures, preliminary requirements of design and control

Jan 1, 1942

By C. A. Edwards

Following a brief introduction, an outline is given of the four main conditions in which gases may be associated with metals; namely, (1) adsorbed gases, (2) dissolved gases, (3) gases in chemical combination, (4) gases entrapped in blowholes or cavities. Adsorption is essentially a surface phenomenon and is regarded as the attachment of outside molecules or atoms to the exposed free valencies of the atoms comprising the surface layers. In many cases where adsorbed films of gas are formed this is accompanied by a process of diffusion of the gas into the metal itself. This is particularly true in respect to iron and hydrogen, and experiments have shown that there is no difference between the rate at which hydrogen diffuses through a single crystal of iron arid through the same material after it has been recrystal-lized into a mass of small crystals. This does not prevent a somewhat greater concentration of gas at the boundaries of adjacent crystals, nor does it mean that the effect of the gas will be the same at the boundaries as it is within the body of the crystals. Indeed, under certain conditions, iron is rendered very brittle at the crystal boundaries, as shown in experiments by Pfeil with samples of almost pure iron. Much work has been done by many investigators concerning the temperature and conditions under which dissolved hydrogen, in particular, can be at least partially removed from different metals. With iron, the hydrogen that has diffused into the metal as a result of acid attack by pickling or by electrolytic deposition of the gas on the metal is partly removed by exposing the metal to the atmosphere at ordinary temperatures. Considerably more can be eliminated by raising the temperature, and even greater quantities by jointly raising the temperature and reducing the pressure. Annealing at suitable temperatures completely removes the bad effects of excessive mounts of hydrogen dissolved in or associated with iron. This is shown by the data plotted in Fig. 1, giving values for electrolytic iron sheets after annealing at temperatures between 250" and 950" C. The hydrogen brittleness is rapidly diminished at

Jan 1, 1935

By H. F. Perkins

CORROSION as an economic problem is growing rapidly in importance not only because it entails a replacement of corroded parts, but because it interrupts operation and causes hazards of damage and injury through failures of corroded equipment. Nearly all industries are interested in this subject. This paper, although concerned chiefly with corrosion in a complete refinery on the sea coast, discusses many of the various forms of chemical decomposition, most of which are found universally. The petroleum refining industry, in the writer's opinion, is seriously afflicted by the presence of sulfur in nearly all crude oils. The complete removal of sulfur from the crude as it enters the plant would cause such a relief from corrosion that this problem for research would seem to demand active attention. Next to sulfur the most troublesome corrosive agent is the saltmagnesium chloride, found in the water associated with crude oil, the last traces of which are so difficult to remove. This is much less serious, however, than the sulfur. Refinery corrosion can be tabulated as follows: Causes of Corrosion and Places of Attack in a Refinery CORROSIVE ELEMENTS MATERIAL ATTACKED Air: Pipe lines Moisture Tanks COQ Electric fixtures Sulfur gases Still towers Chlorine Condenser boxes Other acid-forming gases Ladders and stairs Smoke stacks Steel buildings All exposed metal Water: Alkali Fire lines and hydrants Acids Cooling water lines Air Condensers and coolers Other dissolved gases Boiler tubes Steam Steam pipes and valves Turbines Oil Sulfur compounds Tanks, pipes, valves, stills, towers MgCl2-Hydrochloric acid Condensers Air contamination

Jan 12, 1926

By Leslie W. Austin

ROTARY kiln operators will agree that some of the most severe conditions a refractory must stand occur in the hot zone of a kiln burning Portland cement, dead burn dolomite, magnesite, periclase, and similar materials. Frequently the operator is faced with factors beyond his control which drastically shorten the life of refractories. Shutdown due to mechanical failure can be serious if the period is of sufficiently long duration to cause the dropping of coating or the loosening of the lining. A change in slurry can affect the coating and cause ring buildup. A change in type of fuel and its effect upon the flame can cause a shift in location of the hottest zone. Weekend shutdowns or any other interruption can cause the operator trouble and may damage the refractories, since stopping and starting a rotary kiln is certainly more difficult than stopping and starting a motor. Some operators have tried to set an estimate of damage for each shutdown in equivalent days of running time. Conditions affecting the refractory may be roughly grouped in four classes: chemical attack, mechanical stress, thermal shock, and abrasion. Chemical Attack: The drive to obtain maximum production through a kiln demands maximum operating temperatures, temperatures which are limited more by the ringing up or melting of the clinker. This can cause interface temperatures at the junction of coating and refractory which require the use of a basic kiln block to withstand the chemical attack. Chemical changes take place within the refractory itself, especially in chemically bonded or unburned kiln blocks: These changes cause the formation of the ceramic or burned bond. Migrating liquids or fluxes from the kiln charge have an effect within the refractory and lead to mineral or glass formation. The alkalies, sodium and potassium, migrate into the refractory as silicates, chlorides, sulphates or other salts. They may move under capillary action or may be caused to move by volatilization with condensation in the cooler portion. Mechanical Stress: Concentrated stress may be caused by several factors or combinations thereof. 1-The rings of refractories must be kept tight and rigid within the kiln, and this alone demands considerable force to hold the blocks in place. So that the force will not be concentrated, the blocks should fit the circle as perfectly as possible, with the faces in contact overall. 2-As the kiln is heated, thermal expansion takes place at the hot end of the kiln block. Since this disturbs the plane face it too can cause a concentrated stress at the two ends of the block, and shearing stress can be set up within the brick itself because of the difference in expansion between the two ends. 3-If a lining becomes loose and moves in the shell very severe stress can be set up, and as the kiln rotates this load changes and gives the effect of repeated loading. Permanent expansion of the refractory can also cause severe loading. 4-Not least important, flexing of the kiln is frequently the cause of concentrated stresses. Thermal Shock: Thermal shock, the result of heating and cooling too rapidly, occurs on starting and stopping or when a large patch of coating drops, exposing the bricks. Again, its destructive effect is often the result of phase change, liquid to solid or the reverse; dense refractories loaded with glass-forming impurities are particularly susceptible. Thermal shock is a problem with refractories set in the wall or roof of a stationary furnace, and becomes even more serious in a rotary kiln, the tendency to spall being magnified with movement and concentration of stress. Uniform rate of feed and loading insures both better coating and a more uniform stress. Abrasion: If the refractories do not take a coating, abrasion can become a most destructive factor. Movement of the lining in shell or movement of loose blocks causes abrasion, which is also most destructive if the refractories do not take a coating. An analysis of the problem of basic lining for the hot zone reveals, therefore, a number of desirable characteristics: high refractoriness, basic chemical reaction, resistance to spalling, good strength at all stages, ability to take coating, true sizing, volume stability, and abrasion resistance. Increased demand

Jan 1, 1952