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By Alden B. Greninger

That metallographic structures analogous to the martensite of steel may be found in certain copper-aluminum and copper-tin alloys has been known for many years; similar structures recently were found in certain copper-zinc a1loys.l In all three of these alloy systems the martensite structures result from transformation of the metastable fi phase when the speed of cooling from the B range is sufficiently high to suppress decomposition into equilibrium phases. In the normal decomposition of solid solutions into equilibrium phases, diffusion is needed to bring about the necessary changes in concentration, and the rate of reaction falls almost to zero at temperatures slightly above room temperature. The rates of reaction for martensite processes, however, are not dependent upon temperature; the transformation does not require rendjustments of concentration. For example, the martensite transformation in 60:40 (B) copper-zinc does not begin until the temperature has dropped to about minus 30" C., and then continues down to minus 130" C. and probably even at lower temperatures.' Furthermore, martensite processes apparently proceed only while the tempcrature is falling, within the proper range, and cease completely while the temperature is held constant ;$ and they cannot be suppressed by extremely rapid cooling although the rate of cooling for some alloys may be increased to over 10,000 times the critical cooling velocity. Isaitschew, Kaminsky and Kurdjumow2 account for these observed behaviors of rnartensite processes by postulating that the mechanism 6I... consists in a regular rearrangement of the lattice in such a way

Jan 1, 1939

By Alden B. Greninger

That metallographic structures analogous to the martensite of steel may be found in certain copper-aluminum and copper-tin alloys has been known for many years; similar structures recently were found in certain copper-zinc a1loys.l In all three of these alloy systems the martensite structures result from transformation of the metastable fi phase when the speed of cooling from the B range is sufficiently high to suppress decomposition into equilibrium phases. In the normal decomposition of solid solutions into equilibrium phases, diffusion is needed to bring about the necessary changes in concentration, and the rate of reaction falls almost to zero at temperatures slightly above room temperature. The rates of reaction for martensite processes, however, are not dependent upon temperature; the transformation does not require rendjustments of concentration. For example, the martensite transformation in 60:40 (B) copper-zinc does not begin until the temperature has dropped to about minus 30" C., and then continues down to minus 130" C. and probably even at lower temperatures.' Furthermore, martensite processes apparently proceed only while the tempcrature is falling, within the proper range, and cease completely while the temperature is held constant ;$ and they cannot be suppressed by extremely rapid cooling although the rate of cooling for some alloys may be increased to over 10,000 times the critical cooling velocity. Isaitschew, Kaminsky and Kurdjumow2 account for these observed behaviors of rnartensite processes by postulating that the mechanism 6I... consists in a regular rearrangement of the lattice in such a way

Jan 1, 1939

By P. Barnes

(Read at the Wilkes-Barre Meeting, May, 1877.) THESE furnaces are of the ordinary Siemens type, and present no special peculiarities of construction. The bed of each is 8 feet by 20 feet clear inside of the walls and ports. The producers are placed at a distance of about 200 feet from the furnaces, and the gas is collected in an iron tube and led across the yard overhead. It then drops underground into the gas flue, and is distributed to the furnaces. A considerable weight of floor-plates over the valve-pits is included in account 39, but none of the general stock of floor-plates for the mill were charged to the furnaces. In Table No. 1 is shown the money cost of the furnaces as distributed to the several accounts named. In Table 2 is shown the proportion of each account due to each of the several items or classes of expenditure named.

Jan 1, 1878

By Samuel S. Wyer

The magnitude and economic importance of the problem of correctly valuing natural-gas leaseholds become evident when me consider that: (a) Natural gas is handled in 55 per cent. of the gas distributing plants in the United States. (b) Present known natural-gas acreage forms 47 per cent. of the total known mineral-land acreage in the United States. (c) Five acres of land are now required to protect and maintain continuous service to each of the 2,000,000 domestic natural-gas consumers in the United States. (d) The cost of acquiring and maintaining this acreage of an expendible resource represents a substantial part of the cost of the natural-gas service to the consumer. (e) "The right of a citizen by means of his ownership of or his mining leases on land to draw gas from beneath its surface is property and sometimes valuable property."' A large number of other court decisions have established the basic legal principle that the right to drill for gas within a given area constitutes an interest in the land itself, and is necessarily an exclusive property right. Definition of Vested Interests or Rights "Vested interests are economic interests which are legally recognized to be such that they cannot be impaired by public action, directly or indirectly, without indemnification. Vested interests are largely property interests. The recognition of an interest as a vested interest gives it some of the attributes of property, and by American courts it would be comprised in their very inclusive concept of property. Otherwise than through property, vested interests generally arise through contract."

Jan 1, 1917

By Charles E. Johnston

By substituting photoelectric automatic car loading for mechanically induced hydraulic automatic loading and by protecting the process against operational failures, the engineering staff at International Minerals & Chemical Corp.'s Carlsbad potash mine has developed a reliable loading process that operates without an attendant. The photoelectric control, developed primarily because of frequent failures in the hydraulic control system, has not changed the basic loading operation and physical layout. Mine-run ore ranging in size from minus 200 mesh to 30-in. lumps is dumped onto a conveyor belt which discharges into a so-called "flop gate chute" which in turn, feeds the ore into six-ton capacity mine cars. Each car is filled progressively by moving the entire trip forward. When a car is filled 12 in. above its rim, the direction of flow into the car is reversed 180º and filling of the next car back is begun while the entire trip is moved forward again. Once the next car is properly spotted under the front chute, the flow is again directed to the forward position.

Jan 9, 1962

By Richard Moldenke

A. E. OUTERBRIDGE, JR., Philadelphia, Pa. (written discussion).¬ The fact that iron castings improve with age has long been known. Many years ago the late Sir Frederick Bramwell, a distinguished engineer, formerly in charge of the metallurgical and gun-making department of the Woolwich Arsenal, England, determined to break up a large number of cast-iron mortars of an obsolete type that had been in stock for years. It was then reported to biro that it was found to be much more difficult to break these old gun castings under the "drop" than it was to break similar gun-castings recently made, under his own supervision; he changed the.. composition of the iron and still found that whenever castings made recently were broken up (on account perhaps of superficial defects) great disparity was observed in apparent strength between the old and new castings. Sir Frederick then made many other comparative tests, such

Jan 4, 1917

By R. Bakish, C. S. Barnett

IN experiments on tantalum strained in tension, Bechtold did not observe deformation-twinning even at a temperature as low as that of liquid air.' This is an unexpected behavior for a metal of body-centered-cubic structure. Therefore, it is desirable to determine whether the lack of twinning is an inherent characteristic of this particular metal, or whether the reluctance to twin can be overcome under suitable conditions. The following experiments were performed under conditions favorable to twinning and cleavage in their competition with slip, namely, with impact loading on large-grained sheet at low temperatures. The crystallography of cleavage in tantalum sheet was also investigated carefully because of the remarkable ductility of tantalum at low temperatures and because recent tests on oxygen-embrittled tantalum had disclosed unusual cleavage behavior for a metal of this structure: cleavage primarily on (110) planes and only occasionally on {100}.2 The tantalum, supplied by Fansteel, was of 99.9 pet purity, with the chief impurities being iron (0.03 pet) and carbon (0.03 pet). Coarse grains were produced by the strain-anneal method, the anneal being 4 hr at 2000°C in a vacuum of 10-3 mm Hg, followed by furnace cooling. Impact deformation was applied in various ways: a) by hammer blows on an anvil, the specimen and anvil being immersed in liquid nitrogen ( —196°C), b) by driving a precooled center-punch into the sheet, and c) by bending around a crystallographically determined axis with a hammer blow. The impact-deformation produced bands and slip lines on the surface, Fig. 1. The bands have every appearance of being deformation twins, a) They are tilted with respect to the untwinned surface. b) They have the appearance of Neumann bands in iron, thin lens shape, some having serrated edges. c) The orientation in each is different from that of the surrounding matrix and uniform within a given band, see slip lines within them in Fig. 1. d) Upon repolishing and etching, the difference in orientation and the resemblance to Neumann bands is again evident, Fig. 2. (In this micrograph the slight bend in the bands as they cross grain boundaries was noted frequently and results from the high degree of preferred orientation in the sheet.) e) The bands persist after annealing treatments that would have removed them had they been a low-temperature martensitic phase, e.g., after an anneal of 1/2 hr at 900°C. When back-reflection Laue data were plotted for single-surface analysis of several grains, every trace of the bands in each grain could be explained by (112) planes. In addition, two of the bands were located in space by traces on two surfaces, and these also were found to lie on (112) planes within the error of the stereographic plot. Since (1 12) is the anticipated composition plane for deformation twins in body-centered-cubic metals it is felt that the observations listed above are conclusive evidence for the identification of the bands as twins. Similar tests with impact at —77° and at 25°C produced no twinning. It is concluded that the critical shear stress for slip at the rates of straining used was always low enough to prevent the applied stress from reaching the value required for twinning at these temperatures. It was noted that the serrations along the edges of the twin bands exhibited parallel crystal facets. Several similarly oriented notches are visible in Fig. 1, and a remarkable set is shown in Fig. 3. It appears from Fig. 1 and similar areas that notches are frequently associated with the intersection of a slip line with a twin, although not all such intersections are at notches. In some instances a slip line appears to enter the twin, cross it, reflect from the opposite side and recross it, producing a pattern resembling a notch but without producing the notch itself, see Fig. 1. It is suggested that the stress concentration at the end of a slip line is responsible for these details. The strain energy associated with the pile-up of dislocations at a twin boundary may be lessened by untwin-ning or failing to twin a portion of the twin band, or

Jan 1, 1959

By Theodore Holt

Outline of the Process THE Mines Operating Co.'s plant at Park City, Utah, was designed to treat the low-grade fillings in the old stopes of the Ontario mine. These fillings carry 6 to 14 oz. of silver, 1 to 2 lb. copper, 0.01 to 0.015 oz. of gold, and a small percentage of lead and zinc. The treatment consists in mixing the crushed ore with coal dust and salt and then roasting in a new type of furnace y combustion of the contained fuel. The roasted ore is leached with an acid salt solution to dissolve the silver, gold, copper, and lead. At present these metals are precipitated together on scrap iron and the product sold to a refinery. The only new feature of importance in this scheme of treatment is the roasting process, which makes possible the chloridizing of ores without any loss of the valuable metals, and at a very low cost. History of the Development of the Process The roasting process had its beginning in connection with research work at the Utah State School of Mines. N. C. Christensen, Jr., who held one of the School of Mines' fellowships, was engaged in some experimental work on blast roasting. At the same time I was doing some work on the insoluble gold in Mercur base ores. Mr. Christensen roasted some of this base gold ore in his pot furnace, and found that when he mixed a sufficiently low percentage of fuel with the ore, it did not sinter but roasted to a leachable product. We considered this a new application of blast roasting, and proceeded to test out a large number of ores in several different types of small roasters which we constructed. This experimental work continued well into the summer of 1911.

Jan 7, 1914

By Robert W. Thomas

LEACHING of mined-out areas at the Arizona property of the Ray Mines Division, Kennecott Copper Corp., was started on Jan. 20, 1.937, and by July 1, 1938, 10,000,000 lb. of copper had been produced by this method. Leaching operations at present are confined to the western portion of the ore body and over an area of approximately ten acres. The ore in this area was extremely high in pyrite and the copper content, which averaged slightly in excess of 1 per cent, was the result of incomplete secondary enrichment by solutions which apparently worked laterally from the main ore body. Above the ore was an unaltered zone of primary or protore averaging 125 ft. in thickness and containing approximately 0.6 per cent copper. Above this was the capping or leached zone averaging 50 ft. thick.

Jan 1, 1938

By K. Verghese, R. W. Rousseau, R. P. Gardner

A radioactive tracer method and a size-discretized, mass balance model are formulated and demonstrated in a feasibility experiment for the determination of crystal growth rates in MSMPR crystallizers. The system studied is aqueous KN03 with K-42 as the radioactive tracer. The results indicate that the method should prove to be very valuable for this application, particularly when systems exhibiting size-dependent growth rates are of interest. An indicated refinement to the tracer method is the simultaneous use of an additional tracer in the liquid to determine the amount of radioactivity from the liquid that is adsorbed on the samples of filtered crystals.

Jan 1, 1980

By W. S. Reid

In March, 1938, E. P. Fleming, metallurgist for the American Smelting and Refining Co. inaugurated an investigation into the possibilities of recirculating the gases from Dwight-Lloyd sintering machines operating on lead charge, with the twofold object of concentration of the SO2 content and reduction in volume of total gas produced. The possibility of recovering a commercial grade of SO2 gas from D & L machines operating on lead charge had previously been considered by several investigators. Early History of Recirculation The Selby Smelter Commission Report, published by the Bureau of Mines in 1914, contains a chapter by A. E. Wells regarding results obtained at Selby, wherein some of the richer gas was recirculated through a hood over the pallets. Oldright and Miller of the U. S. Bureau of Mines had also made tests at Trail, B.C., and at Kellogg, Idaho. R. C. Rutherford, while at the Chihuahua, Mexico, Smelter of the American Smelting and Refining Co., in May, 1937, proposed recirculation of D & L gases to decrease the volume of gas handled by the baghouse. At none of these plants, however, was the operation commercialized. In July, 1938, Mr. Fleming, in correspondence with the Selby Plant, inquired regarding the possibility of obtaining 6 pct SO2 gas from the Selby D & L machines. At that time, the writer advised that there was slight possibility of obtaining 6 pct SO2 gas without re- circulation, but believed that it was possible with recirculation, and that experimental work toward that end should be tried at some plant where spare D & L machines were available. The foregoing statement was based on the following information then available— 1. Tests on Selby first-over machines showed 2.28 pct SO2 from first windbox and 1.03 pct SO2 from second windbox, and corresponding figures for second-over charge of 0.81 pct SO2 for first windbox and 0.08 pct SO2 for second windbox. 2. Oldright and Miller (US. Bureau of Mines) in 1932 at Bunker Hill, on 42 in. X 22 ft machines found: a. First-over charge—Maximum SO2 concentration (leaving cake) of 9.5 pct. b. First-over charge—SO2 concentration of over 8 pct from the 4 ft to the 12 ft points beyond the front dead-plate and that the concentration then dropped rapidly. c. That approximately 80 pct of the total sulphur eliminated on the second-over machines occurred during the travel of the pallets from the 1 ft to the 6 ft distances from the dead-plate. d. That approximately 94 pct of the total sulphur eliminated on the second-over machines occurred over the first windox. 3. Oldright and Miller (US. Bureau of Mines) in 1932, at Trail, on 42 in. X 50 ft machines found: a. First-over charge—SO2 varied from 2.0 pct to 5.5 pct (leaving cake) from the 12 ft to 28 ft points from the deadplate. b. That the average SO2 increased from 1.0 pct at 7 ft from dead-plate to maximum of 3.3 pct at 20 ft, then dropped to 1.5 pct at 40 ft. c. That on a 22 ft, second-over machine with an 11 in. bed the SO2 varied from 4.5 pct to 6.5 pct from the 2 ft to the 8 ft points from the dead-plate. d. That on the final roast, the SO2 concentration also varied across the pallets; that is, 2 1/2 pct at the side, increasing to 6.0 pct, 5 in. in, and to 7.0 pct at 10 in. to 20 in. in, then decreased vice versa at the opposite side. e. Concluded that most of the sulphur on a 22 ft machine was removed over the first 7 ft of the first windbox; therefore, they partitioned the first windbox so that the exit gas from the second 4 ft section was returned to the surface of the pallets over the fist 7 ft section, and during a seven-day trial the gas from the 4 ft section averaged 2.4 pct SO2, while the recirculated gas from the first 7 ft section only increased to 3.8 pct SO2. (Excess suction over the 7 ft section to prevent escape of SO2 laden gas from the 4 ft section caused dilution by air.)

Jan 1, 1950

By G. A. Beiswenger

The application of the law of supply and demand to the sale of crude oil is generally conceded, but the motives underlying the buyer's (refiner's) demands are not always obvious to the seller (producer). In some cases this obscurity has led to the conclusion that the refiner may be unnecessarily particular when he selects one crude and rejects another. This preference, however, is very largely the reflection of the refiner's product demands and the quality of the stocks obtainable from the selected crude. The purpose of this paper is to point out critical characteristies of the major classes of refined products and to show how crudes vary in their suitability for such products. With relatively few exceptions, available processing methods and addition agents make it theoretically possible to produce any type of refined product from any crude source, although it may not be economically sound to do so. The widespread application of thermal cracking for converting higher boiling stocks into gasoline is well known. More recently cracking and refining in the presence of catalysts9 have been developed, as well as various processes for polymerizing lighter hydrocarbons into gasolines having desirable characteristics.6 For several years, selective solvents have been applied commercially to refining inferior quality kerosene, Diesel fuel and lubricating oil distillates.3 Improved methods for refining lubricating oils from crude residual4 formerly suitable only for fuel, are now in use and a number of special solvent processes are available for dewaxing lubricating oils to low pour point.5 These improved refining methods have been developed not only to meet the demand for improved product quality but also to enable the refiner to obtain quality products from crude sources that would not yield such products by the older refining methods. In many cases, the utilization of these modern refining tools necessitates an appreciable expenditure for equipment as well as added manufacturing costs, and their application therefore must be justified economically. Despite the availability of such tools, the added processing costs involved and yields obtainable may render their application entirely impractical. To illustrate this point, inspections of typical cuts from various crudes

Jan 1, 1940

By OTTO HERRES

TO operate the bituminous coal industry in the United States in 1929 cost $770,237,000, of which $30,739,000 was paid for purchased power and $34,947,000 for new machinery and equipment. Equipment aggregated 3,124,000 hp. A mining industry that spends $65,000,000 a year for power and machinery is likely to be fairly well mechanized, and when the machinery in use takes three million horsepower to drive it, the probabilities are that mechanization has been in progress in at least some of the mines for quite a few years. Mechanization in its broadest sense implies machine cutting, power drilling, mechanical loading, electric haulage, mechanical sizing and cleaning, and lesser applications of machinery to mining operations. But the introduction and development of mechanical loading has been the feature of coal mining recently and its extraordinary progress is causing great changes within the industry. First, let us look at the records. The quantity of coal loaded mechanically in bituminous mines was:

Jan 1, 1933

By Fred J. Miller

FRED J. MILLER was born in Ohio, in 1857. He had a common and high school education, supplemented by personal study and special instruction. After serving a 4-year apprenticeship and working in various capacities in machine shops, he became a contributor to mechanical journals and finally a member of the editorial staff of The American Machinist, where he remained for twenty years, the last ten years as editor-in-chief of the magazine, and vice-president of the publishing company. On retiring from journalism, he was for nine years general manager of a group of typewriter factories, and was then commissioned Major of Ordnance in the U. S. Army, being stationed during most of his service at Rock Island Arsenal, where he organized the Civilian Service Division of the Arsenal. He is now a member of the Technical Advisory Committee of the War Claims Board at Washington. Major Miller became a member of the American Society of Mechanical Engineers in 1890, and has always taken an active interest in its affairs, having served on a number of important committees, and as a member of Council from 1904 to 1907, inclusive. He was elected President in December, 1919.

Jan 1, 1920

By Bernard Rachlin

In the mineral industry measurement of density or specific gravity of slurries is often necessary or highly desirable. To date the most successful method of measuring the specific gravity of various media is to hand weigh a constant volume sample of the slurry. This method is time-consuming, however, and is intermittent rather than continuous. Most density measuring instruments in use today are variations of three basic systems: air bubble tube systems, radioactive methods, and displacer systems. The high cost of the radioactive cell, combined with the precision electronic measuring that is required, limits the practical utility of this procedure to a small percentage of critical processes. In the air bubble systems clogging of the bubble tubes with solids has rendered this type of measurement completely ineffectual for many applications. Continuous or intermittent purging of the bubble tubes with air or water to prevent tube clogging has been tried but has not been very successful, especially in the heavy media process.

Dec 1, 1956

By Frederick F. Frick

SPONGE iron as produced at Anaconda is a fine, -35 mesh, impure product, about 50 pct metallic iron, obtained from the reduction of iron calcine at a temperature of 1850°F by use of coke resulting from slack coal. The metallic iron particles are bulky and spongey and precipitate copper readily and rapidly from a copper sulphate solution. Investigation of the treatment of Greater Butte Project, Kelley, ore at Anaconda early showed the desirability of using sponge iron as a precipitant for the copper in solution resulting from desliming of the ore in a dilute sulphuric acid solution. Anaconda had done considerable work on the production of sponge iron in 1914 for use as a precipitant of copper from leach solutions. Some success and considerable experilence were attained at the time. indicating that, sponge iron might be successfully made by a modification of the process used in 1914, a batch process in which an iron calcine was reduced by means of soft coke, resulting from noncoking coal, in a Bruckner-type revolving horizontal cylindrical furnace widely used 50 years ago. The coke and calcide formed the bed in the Bruckner furnace, which was rotated at about 1 rpm. The bed was brought to a temperature of about 1800°F by means of an oil flame over the surface. Although results were reasonably satisfactory, they did not warrant full development of the process at that time. A good deal of work has been done in the last 50 years on the production of sponge iron. The objective in some cases has been the production of a precipitant for copper from solution, but the bulk of the work has been done for the production of open-hearth steel furnace stock. The production of an open-hearth stock presents two problems rather than one: first, producticon of the sponge iron, and second, what is perhaps of equal difficulty and importance, conversion of the sponge iron into a form suitable for use in the open-hearth furnace. So far as is known to the writer, none of the sponge iron processes tried in the past have proved to be economically feasible. However, Anaconda had a combination of conditions appearing to justify an attempt to produce sponge iron which would serve for the leach-precipitation-float process. It was thought that the process used in 1914, if changed to a continuous one, might work out satisfactorily. The following favorable conditions at Anaconda justified the investigation: 1—A sufficient tonnage of good grade iron calcine resulting from the roasting of a pyrite concentrate in one of the acid plants, at substantially no cost. 2—Reasonably cheap natural gas. 3-—The fact that there was no need for production of a high grade product. 4— The fact that there was no need for obtaining a consistently high reduction of' the iron in calcine. A small revolving Bruckner-type furnace about 2 ft ID by 4 ft long was set up for early pilot work at the research building. This pilot furnace showed that a satisfactory product could be obtained at reasonable cost. It also indicated a marked advantage in preceding the reduction furnace with a furnace of similar size and capacity for preheating and roasting out any residual sulphur from the feed. The small furnace was operated for several months, various details of the process were worked out. and sponge iron was produced to supply a pilot LPF plant which treated 300 lb of Kelley ore pel- hr. Later a second pilot furnace 5 ft in diam and 12 ft long inside was set up at our reverberatory furnace building. This furnace confirmed the data of the small furnace and gave a basis for design of the final plant. At Anaconda a pyrite concentrate, running about 48 pct S, is recovered from copper concentrator tailings by flotation. This concentrate is roasted to sulphur of 3 pct or less at the Chamber acid plant. The iron calcine contains about 57 pct Fe and 18 pct insoluble. The iron calcine feed, as mentioned before, is re-roasted and preheated in a reroast furnace preceding the reduction furnace. Both are of the Bruckner type. The reroasted calcine is fed into the reduction furnace at 800" to 1000°F along with 30 pct slack coal. In the feed end of the furnace the volatile is burned from the slack, giving a soft coke which readily serves for reduction of the iron. Hard metallurgical coke will not serve the purpose. since it does not reduce CO readily at a temperature of 1850°F. All indications are that the actual reduction of the iron is accomplished by carbon monoxide below the surface of the bed, which is 30 in. deep at its center. Apparently there is a constant interchange: Fe²O³ + 3CO = 2Fe - 3CO², CO² + C = 2CO Actually iron oxide is reduced by CO at somewhat lower temperature than the 1850 °F used in the process. but this temperature is necessary to obtain a satisfactory rate of furnace production. The furnace atmosphere is generally reducing, and typical blue carbon monoxide flames satisfactorily cover the bed. Gas flames from four 3-in. Denver Fire Clay Inspirator burners are played directly on the bed, which is slowly cascaded by the 1 rpm of the furnace. An excess of coke is necessary to assure maintenance of good reducing conditions in the furnace bed. Part of this coke is recovered for re-use.

Jan 1, 1954

By AIME AIME

TEXAS not only produces millions of barrels of petroleum daily, but supplies the oil industry with an asset infinitely more valuable than liquld gold. That asset is leadership. The oil industry was built from its humble beginning a few decades ago into a potent force in world economy by human hands and human brains. One of these great leaders in the busy world of oil is Wallace Pratt, of the Humble company, who has been called to a position as director and member of the executive committee of the Standard Oil of New Jersey. So reads the Houston Post of June 3, 1937.

Jan 1, 1944

By C. F. Mabery

So far as the elementary composition of petroleum is known, it may be briefly stated. Petroleum consists principally of a few series of hydrocarbons, with admixtures of sulfur, nitrogen, and oxygen derivatives in comparatively minute proportions, which may be regarded as impurities to be removed in the preparation of commercial products. But as each series is represented by many homologs, in the aggregate, crude petroleum is an extremely complex mixture of hydrocarbons and their derivatives. In part, these hydrocarbons individually conform in structure to the system of synthetic hydrocarbons whose structure is well defined and represented by the typical series CnH2n, + 2, C.H2n, the series CnH2n,-2, CnH2,-a, the members of which have not been sufficiently studied to establish their structure, and the series CnHz,e composed of the aromatic group, benzene and its homologs. Hydrocarbons of greater density contained in the portions of petroleum that cannot be distilled without decomposition doubtless have less hydrogen than is represented by these formulas. Since to every hydrocarbon there is a definite temperature, even in vacuum, at which its constituent carbon and hydrogen atoms fall apart, and since for the heavier bodies this temperature is not much above 360" C. in vacuum, it is evident that some other method than distillation must be devised for their separation if anything further is to be learned concerning their individual constitution. Classification of Petroleums There is such a wide variation in the composition of petroleum from Merent fields, it would seem possible to make a classification on this basis were it not that no single variety is entirely free from hydrocarbons contained in others. Such a classification has been suggested of the exceptionally pure Pennsylvania petroleum, the sulfur oil from Trenton limestone and other sources, the California oil with its large amount of nitrogen (quinoline) derivatives, and the Russian oil, composed chiefly of the naphthene hydrocarbons.' A commercial distinction is made

Jan 1, 1921

By Brigitta Hassler

INTRODUCTION In the early 1960's research was begun in Sweden to improve the agglomeration of our domestic iron ore concentrates (5). Different agglomeration methods that were used in the building material industry were studied under the economic support from the Swedish Technical Council, the Swedish Board of Technical Development and by the Swedish industry. The research work was performed at the Division of Mineral Processing at the Royal Institute of Technology in Stockholm. All known agglomeration methods were reviewed and the methods were developed to produce superior quality agglomerates (6). The term cold bonding (in contrast to sintering) was introduced to describe the induration operation in these processes and this has been accepted internationally. Even though we used it mostly for steam autoclaving methods, it has come to describe a class of processes that use binding methods by pore filling. Schumacher in Germany discovered around 1907 that a strong material can be produced by mixing slaked lime with fine ground quartz and subjecting to a steam atmosphere under pressure at about 185ºC. This started development of lime-sandstone building materials and later on, in Sweden, the light-weight concrete. Schumacher also used the same reaction for briquetting iron ore concentrates by adding silica and lime, and autoclaving. The product seems to have been accepted for blast furnace burden and the process was used on an industrial scale until the 1920's. The sintering method has a small melting phase as diffusion medium and in the steam-autoclaving method a small quantity of water condensate at about 200°C serves the same purpose. Thus the induration process by the hydrothermal hardening methods is similar to that of sintering or heat treatment.

Jan 1, 1977

By T. T. Read

TWO papers on health and safety were given Thursday afternoon when a joint session of the Health and Safety Committee and the Mining Methods Committee was held. T. T. Read presided and the first paper, on ventilation at Climax, was presented by the author, L. H. Glanville. In the subsequent discussion by Cloyd M. Smith, P. B. Bucky, B. F. Tillson, D. F. Haley, J. L. G. Weysser, and others a number of interesting points not covered by the paper, which appears in full in the January Mining Technology, were brought out. Ventilation troubles in mines so often hinge on the air being too hot and damp that it was interesting to hear of one where it is frequently too cold and too dry.

Jan 1, 1943