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By J. D. Cannon

SLAGS studied in this investigation were from 0.25 to 0.35 pct plain carbon steels and were melted in a 3-ton acid-lined Lectromelt furnace with a 2500-kva transformer. The melting process employs a short, violent boil, which is partially blocked, and the desired carbon content is adjusted by pig iron or iron ore, depending on the preliminary carbon. A relatively small volume of slag is used in refinement. Bottom is here defined as that portion of the furnace that comes in contact with the molten metal, or all the surface below the slag line. Bottom trouble-i.e., holes in the bottom lining-is very seldom experienced at our plant. We have been watching the bottom lining over a period of some boo heats in the hope of having holes large enough to supply data for this report, but none occurred during that period. The bottom is eroded uniformly, occasionally with slightly deeper depressions around the taphole.

Jan 1, 1947

By Read Winterburn

This study of the relationship of the accumulation and drainage of oil to the structural conditions in the Wilmington oil field is presented with the hope that the data contained herein will aid in efficient exploita-tion of other fields where similar conditions exist. It is also probable that the conditions observed in this field will enable accurate comparisons of various well-spacing programs as to efficiency of production and ultimate recovery. Formations in Wilmington Field Age Formation Thickness Lithology and Remarks Quaternary and Pleistocene. San Pedro 1000 t Fresh-water sands, gravels and clays Pliocene Upper Pico 800 t Alternating sands and silt- Stones Pliocene Middle Pico 0-200 ± Sands and siltstones Unconformity Pliocene Repetto 875-1150 Gray and green shales, silt-stones and sands at top grading to interbedded gray-ish brown shales and fine-grained sands toward bot-tom Miocene Puente 4100± Hard brown shales and sands. Sands are fine and uncon-solidated at top, becoming firmer and coarser grained toward bottom. Top por-tion contains layers of lam-inated diatomaceous shale Unconformity Schist The data included herein are not complete as to all areas and zones, being confined mostly to the area south of Anaheim Street. The sections presented are illustrative of edge-water conditions in the Terminal zone and Tar zone, but have not been extended down the structure far enough

Jan 1, 1940

By G. E. Klinzing, S. H. Chiang, R. M. Kakwani

Filtration and dewatering results of -500 µm (-32 mesh) Pittsburgh seam coal are discussed with reference to the microscopic structure parameters, i.e., particle segregation in the cake and particle and pore size distributions at different layers. At low solid concentration of 0.33 kg coal/kg water, a non-uniform cake structure is observed where particle and pore sizes increase from the top to bottom layers in the filter cake. An increase in the solid concentration in slurry produces more uniform cake structure and higher filtration and dewatering rates. Air bubble entrapment in the coal filter cakes is also discussed.

Jan 1, 1985

By W. R. Shimer

IN his valuable report on Finishing Temperatures and Properties of Rails, I Dr. G. K. Burgess, Chief of the Division of Metallurgy, U. S. Bureau of Standards, has begun a line of investigation which should be continued by those interested in the subject, and who have proper facilities for carrying put the work. For the past year or more the Bethlehem Steel Co. has been conducting experiments to learn the effect of rail finishing temperatures on their physical properties and microstructure and the results are here given for the consideration of those interested in the rail situation. . Considerable differences of opinion have been expressed by various authorities, in the past, as to the effect of large or small grain size and high or low finishing temperatures of steel rails on their physical properties and wearing qualities. Low finishing temperatures and, therefore, low shrinkage, have been advocated on the theory that the wearing qualities would be improved. Others have recommended high finishing temperatures. The generally accepted cause for rail failures, due to the development ,of transverse fissures, is excessive wheel pressure on hard rails. One of the causes advanced for hard rails has been that they contain too high per centages of carbon and manganese; another that the rails were finished at too low a temperature, i.e., at or near the critical point. In the experiments herein described the rails were rolled from reheated blooms. All the rail blooms were charged hot in a reheating furnace and brought up to about the original ingot-rolling temperature before rolling into rails. These rails gave better results in deflection, withstood a greater number of drops before breaking, and showed greater ductility, than. rails of identically the same composition and section which were rolled, direct from the ingot. Rails rolled from reheated blooms, finished at somewhat higher temperatures than when rolled direct from the ingot, have a different microstructure, which the writer does not believe is due so much to the difference in finishing temperatures, as to the difference in

Jan 3, 1915

Discussion of the paper of W. R. SHIMER, presented at the New York meeting, February, 1915, and printed in Bulletin No. 99, March, 1915, pp. 557 to. 585. WILLIAM R. WEBSTER, Philadelphia, Pa.-I would like to ask Mr. Shimer how the finishing temperature of the H-beams and other beams rolled on the Gray mill at Bethlehem compare with the rolling temperatures of the rails referred to in this paper. Also, how the reductions in the rolling of the beams compare with the reductions in the rolling of the rails. I would also like to know if any drop tests were' made on the rails referred to as having been allowed to cool and then annealed; in other words, what results, if any, were obtained from tests on rails after the internal strains of rolling had been removed; and in the matter of the rail blooms, I would like to ask if they are not often heated to a higher temperature than is desirable on account of the thin flanges in order to carry the heat through to the finishing pass. The tensile strength of the steel in these rails is given as 125,000 lb. per square inch, which is almost as high as tire steel. If some of these blooms were rolled into rounds of about the same section as the head of the rail, would you not get better results from tension tests than those from the head of the rail? In other words, in rolling rounds, whether you would not be able to control the rolling and finishing temperatures better than is possible in the rail, owing to thin section of the rail flanges. Some years ago I had experience with the rolling temperatures of tire steel, running from about 127,000 to 133,000 tensile strength. These tires had the tensile strength and the deflection specified. One of the manufacturers had no trouble whatever, after a little experimenting, in meeting the conditions of the specification. Another manufacturer who made some of these tires came to the office and stated that he had tried tires from three heats of steel and could not meet the specifications and

Jan 5, 1915

By Leslie C. Richards

The competitive position of producers of industrial minerals depends upon the delivered price of their product. Freight charges are a major factor in the sales to consumers. A comparison of freight rates on movements of limestone and silica rock in the Pacific Northwest shows a wide variance in mills per ton mile for like hauls, thereby favoring some localities over others.

Jan 1, 1950

By G. J. Armstrong, K. S. Lynch, C. G. Thomas, L. A. Baker, R. J. Cornelius

The presence of geothite in a hematite ore has been shown to strongly affect the time of heating to the firing temperature. The investigation of spalling of single pellets and of packed beds has enabled free water and goethite spalling to be identified as separate phenomena. In addition, it has been shown that even for an 18-in. deep bed of green balls, the free water and goethite drying periods can be considered separately. Based on this observation, a method of predicting production rate and hood temperature profile is presented. The method required knowledge of the ore goethite content, ore grind, and the green pellet bulk density. Laboratory results were found to be in good agreement with actual plant practice and have led to improved process performance.

Jan 1, 1974

By C. F. Riisness, E. R. Parker

THAT grain size has a great effect on the mechanical properties of metals has been recognized for a long time. Bassett and Davis1 in 1919 did excellent work in [ ] determining the effect of grain size on the hardness of brass. About the same time Jeffries2 and Sykes3 ascertained the effect of grain size on the strength and ductility of several metals at temperatures ranging from 80°K. to their melting points. When creep was recognized as an important property of metals, those engaged in the study of this property tried to determine the effect of grain size 4-9 on creep rates. Unfortunately, most of the investigations were conducted on only two grain sizes, often designated simply as "fine" and "coarse." It is well known that at high temperatures coarse-grained test bars creep less than fine-grained bars. The relation between grain size and size of test bar, [ ] however, has been frequently overlooked. In his early work, Jeffries2 showed that the number of grains in the cross section has a more important influence on the properties of the material than the actual grain size. More recently Hanson and Sandford10 and Pell-Walpole,11 in their measurements of the creep and tensile properties of tin, tested a wide range of grain sizes and correlated the grain size with the strength. Hanson9 later established the relation between the number of grains in the cross section and the. creep rate: At high temperatures, generally a coarse-grained structure is considered superior in creep to a fine-grained structure, but it is evident that for a given bar size continuously increasing the grain size will

Jan 1, 1944

By William J. Craig, Harold L. Walker

INDUSTRY has for many years recognized the dependence of certain mechanical and physical properties, as well as workability, upon grain size variations in brass. Although the dependence of properties upon grain size has been recognized there are not many instances where a planned program of testing has been conducted and where the only intentional variable has been grain size. In particular the literature is limited with respect to the effect of grain- size on the endurance limit, though there are many industrial applications where the brasses are subjected to cycles of repetitive stresses. LITERATURE A number of the physical and mechanical properties of a given brass sheet, in the annealed condition, will depend upon: (I) The ready-to-finish grain size before final rolling, (2) the percentage deformation by cold working, and (3) the time and temperature of annealing, The first and second variables affect the recrystallized grain size, and the third variable affects the coalesced grain size. Gibbs1 has shown the effect of two different ready-to-finish grain sizes upon the tensile strength and hardness of deep drawing brass strip after a definite amount of cold rolling. The smaller the ready-to-finish grain size, the higher the tensile strength and hardness, but with lowered ductility, Gibbs also demonstrated, for a given time and temperature of anneal, that the tensile strength, hardness, and elastic limit are higher for the smaller ready-to-finish grain size, but the elongation is lowered, Townsend and Greenall2 have reported data which show that cold working increases the tensile strength, hardness, and load carrying ability of deep drawing brass sheet under reversed stress. Greenall and Gohn3 have reported data which show that the smaller grain sizes have higher tensile strength and hardness properties, and the data also show that increased cold working increases the tensile strength and hardness properties of deep drawing brass sheet. Kommers4 has reported data for tests of brass of known ready-to-finish grain size, a specific amount of cold reduction, and annealed at different temperatures above and below the recrystallization temperature. Kommers' results indicate that annealing below the recrystallization temperature does not change the tensile strength and hardness properties, but the endurance limit may be increased from 22,000 to 28,000 psi. The increased endurance limit is explained as resulting from the reduction of internal stresses by a stress-relief anneal. Burghoff5 and associates have reported data on creep tests, over

Jan 1, 1948

By M. E. Learmont, I. Iwasaki

Grinding with steel media adversely affects the flotation response of galena. Electrochemical measurements, flotation tests, and AES, XPS, and STEM examinations were employed to identify interactions between galena and mild steel. Iron oxide, hydroxide, or sulfate species that formed on the galena surface upon contact with mild steel decreased its floatability, with the time of contact and aeration condition affecting the severity of the flotation depression. Parallel tests performed with an active metal, magnesium, indicated that floatability was also affected by the presence of a surface coating involving lead species.

Jan 1, 1985

By S. R. Rao, J. Leja, K. S. Moon

A prolonged grinding of sulphide ores in steel mills appears harmful to flotation recovery and selectivity whenever xanthates are used as collectors. Particles finer than about 10µm show a pronounced decrease in floatability. A supposition was made that the cause of the reduction in floatability of ground sulphides is the presence of metallic iron abraded during grinding and deposited on the ground particles. Electro- chemical measurements were made of mixed potentials developed by different sulphide-mineral electrodes (galena, chalcopyrite, pyrite, marmatite, pyrrhotite) in xanthate solutions, without a direct con- tact or in contact with a metallic iron electrode. These measurements showed that without a galvanic contact between the sulphide and the iron, the values of mixed potentials were in the vicinity of the xanthate/dixanthogen redox potential. When contact with iron was established, the mixed potentials shifted towards the more negative reducing or cathodic values. The shift was greater the higher was the ratio of the surface areas: iron electrode to sulphide electrode. Further, the shift in mixed potentials was greater the more reducing were the conditions on the sulphide electrode. Chemical analysis of reaction products produced on the surfaces of sulphides and in the bulk solution showed that less thiosulphate was formed in all of the sulphide-xanthate systems and that more elemental sulphur was detectable on the pyrite and marmatite surfaces. Adsorption of xanthate parallels the amount of thiosulphate formed with which xanthate is exchanged by metathesis. If the supply of oxygen is limited, the demand for oxygen by the abraded metallic iron competes with that by the valuable sulphide, resulting ultimately in poorer hydrophobicity. If excessive amounts of pyrite or pyrrhotite are present as well, the conditions are so reducing that there is little adsorption of xanthate ions on the valuable sulphides to make them hydrophobic and floatable. The presence of increased quantities of sulphur on pyrite or marmatite is responsible for a non-selective flotation. Flotation tests on synthetic mixtures with and without metallic iron powder in the feed confirmed the above conclusions from electrochemical and chemical measurements.

Jan 1, 1976

By Clarence Merritt

STAINLESS iron, as mild stainless steel is usually called, an alloy ranging from 11.50 to 15.00 per cent chromium with carbon under 0.12 per cent, has been considered to be not appreciably affected in respect to corrosion resistance by heat treatment. This metal, while one of the most widely used of the "straight" chromium stainless alloys, has failed in many applications because of insufficient information regarding heat treatment. These failures have been attributed to many possible causes from an inherent lack of resistance to corrosion and misapplication to mysterious electrolytic effects or comparatively minute non-metallic inclusions. Many uses for a steel with such excellent physical properties is are latent in this alloy have been lost on account of corrosion failures which could have been avoided by applying proper heat treatment. The alloy has not received the recognition or attention it should because of the fact that' the details of its metallurgical behavior were not thoroughly understood. Response to heat treatment of the steel is well known as regards tensile properties, 1,2 but its application has been for improvement in tensile characteristics or on account of machining considerations rather than for corrosion prevention. The potential user of this steel has not been clearly advised in papers, either technical or commercial, that have been written about it in the last 10 years or more, of particular features that are of prime importance in developing the excellent properties of this metal. The data to be presented in this paper are concerned mainly with the effect of heat treatment on the corrosion resistance, but a study has also been made of the concurrent microstructural changes and an explanation developed for the phenomena revealed, as well as a correlation to the other physical properties-hardness, tensile characteristics and impact strength. Stainless steel, largely used for cutlery purposes, an alloy of approximately 13.00 per cent Cr with 0.30 per cent C, must be hardened and the surface prepared by polishing or pickling for best resistance to staining and corrosion.3 Monypenny reports that a loss of hardness is

Jan 1, 1932

By B. Egeberg

IN A previous paper1 the authors dealt with the physical properties of cold-rolled and heat-treated Britannia metal of the approximate composition Sn, 91 per cent., Sb, 7 per cent. and Cu, 2 per cent. It was found that cold rolling to more than 50 per cent. reduction produced a continuous softening of the metal when measured by the Brinell machine, whereas the Shore instrument indicated increased hardness; that the strength of the material followed the Brinell hardness and that the metal therefore became weaker the more it was cold-rolled; and further, it was found that hardness and strength could be largely restored to the cold-rolled metal by "baking" for about one hour at any temperature, between 200° and 450° F., the melting point. The higher the baking temperature, the more effective was the heat treatment as far as increased hardness was concerned. It seemed to be of little importance whether the metal was soaked or not at the baking temperature for a great length of time and the rate of cooling seemed to be immaterial. The present paper deals with the same alloy and more particularly with the resistance towards various forms of stress - tensile, bend and deep drawing. The metallography of Britannia metal has in part also been covered and an explanation attempted for the abnormal behavior of this alloy.

Jan 1, 1929

By Kazutami Imai

Effects of heavy metal ions on the growth and the activities of iron and sulfur oxidation of Thiobacillus ferrooxidans were investigated. Mercuric, silver, and stannous ions inhibited both of the growth and the iron- oxidizing enzyme system of the bacterium. On the other hand, uranyl ion inhibited the growth, but it gave almost no effect on the iron-oxidizing enzyme system. The inhibitory effect of uranyl sulfate on the growth of the bacterium is intensified on lowering the cultivating ' temperature from 28 ºC to 7 ºC. In the concentration of 10-3M, cadmium and copper ions inhibited colloidal sulfur-oxidizing activity of the cells 69 and 52 %, respectively, though they did not inhibit the iron-oxidizing activity at all in the concentration. On the contrary, stannous chloride did not givr any effect on the sulfur-oxidizing activity of the cells, though it inhibited the iron-oxidizing activity 55 % in the concentration of 10-3M. Several differences were observed among the cytochrome systems of cell-free extracts of the cells grown on iron and on sulfur.

Jan 1, 1976

By JAMES J. DOUGHERTY

THIS paper is a general discussion of developments in our reverberatory smelting practice during the past five years. It deals briefly kith changes in furnace types ; changes in furnace feed ; de- crease in the amount of slag produced; relation of slag assays to copper loss in the slag; increase in the grade of matte and furnace capacities. The reverberatory is but one unit in the copper plant ancl 'any discussion of it must be considered with reference to the other units and to the plant as a whole. A change in the grade of concentrates at the concentrator puts an entirely new aspect on reverberatory smelting and, likewise, a change in the grade of matte at the reverberatory affects the rate and cost of converting. The introduction of differential flotation in 1927 had a very marked influence on all smelting operations and its effect will be noted

Jan 1, 1930

By Carl Scholz

Discussion of the paper of Carl Scholz, published in Bi-monthly Bulletin, No. 22, July, 1908, pp. 551 to 559. HOWARD N. EAVENSON, Gary, W. Va. (communication to the Secretary*) :-For some time before the publication of Mr. Scholz's paper, I had been collecting data bearing upon its subject, and I now take pleasure in presenting my results to the Institute in the form of a discussion. It has long been a matter of common opinion among mining-men that mice-explosions are, more frequent during the colder, or winter months, than during the warmer ones, and it is a matter of common knowledge among them that the air-ways and road-ways in most mines are much drier and are more in¬clined to be dusty during the winter than during the summer. In many mines, places which are wet and sloppy in the summer are dry and sometimes dusty during the winter. These changes, of course, can only be due to atmospheric conditions, and are caused by differences in temperature and humidity. Until recently, however, very little attention has been paid to the part that atmospheric conditions may play in mine-explosions, or, rather, to the effect they may have in rendering mine-conditions peculiarly dangerous, and in spreading and rendering more disastrous the effects of what would otherwise probably have been .small explosions. To show the difference in mine-conditions during sunnier .and winter months, I have tabulated in Table I. the results of 24 observations of hygrometric conditions in several different mines at different times of the year. Mines Nos. 1, 2, and 6 are located in the Pocahontas.coal -region, in McDowell couuty, W.Va., the first one being a shaft-mine shaft mine and the others drift. Mines 1A and 2A are drift-mines located in Logan county, W. Va. All of these are mines of fair size, but none of them has been in operation more than six years,

Jun 1, 1909

By Carl Scholz

DURING November And December, 1907, Four Serious Mine-explosions Occurred In The Appalachian Coal-Field, Which Resulted In The Loss Of Nearly A Thousand Lives And Caused An Enormous . Damage To Property. These Accidents Attracted More Than The Usual Attention; Coal-Trade And Engineering Papers Contained Many Comments And Suggestions On The Cause And Prevention Of Accidents; The Daily Press In Many Instances Condemned The Coal-Operators And Charged These Accidents To Their Negligence, Or Their Anxiety To Make Money Without Adopting Precautionary Measures. Immediately After Each Accident The Respective State ..Authorities Ordered Close Investigations To Be Made, With The View Of Establishing The Cause And Suggesting Remedies To Prevent Recurrence. Representatives Of The Technologic Branch Of The U. S. Geological Survey, To Whom The Investigation Of Mine-Accidents Had Recently Been Delegated By The Secretary Of The Interior,. Visited The Mines And Co-Operated With The Local Authorities In Their Determinations. It May Be Safe To Say Here That An Investigation Of A Mine After An Explosion Has Occurred Discloses But Little, Because. The Causes Have Been Removed And Conditions Have Been Entirely Changed. On Jan. 8, 1905, The Coal-Operators Of West Virginia Organized An Association At Washington For The Purpose Of Making Extensive Investigations, And Sufficient Funds Were Pledged To Carry Out This Work. At This Organization Meeting, The Representatives Of The Geological Survey Present Had No Suggestions To Offer As To The Cause Of These Accidents. An Examination Of The Various Reports Concerning These Accidents Indicates That The Explosions Were Caused By The Ignition Of Gas Or Dust; They Show The Point Of Origin And The Direction In Which The Force Was Expended, And Give A Detailed Description Of The Damage Done. Very Little Has Been Said As To What

Jan 7, 1908

By Corale Brierley

The effect of hydrogen peroxide (H202) on growth and respiration of Thiobacillus thiooxidans and Thiobacillus ferrooxidans, organisms involved in acid leaching of copper sulfide minerals and uarnium oxides, was examined. Oxygen uptake and growth by T. thiooxidans were totally inhibited after contact with 0.82 mM H202. Complete inhibition of oxygen uptake by T. ferrooxidans occurred at 8.75 mM H202, and growth was inhibited after 6 hr exposure to 2.06 mM H202. Higher concentration of H202 can be used without detriment to thiobacilli if it is dissipated prior to reaching the oxidation pond or dump surface.

Jan 1, 1980

By Karl Sundberg

ELECTRICAL investigations carried out in regions containing sedimen-tary rocks showed that sediments generally are good electrical conductors, a fact which at the present time is used for structural investigations by electrical methods. It is of fundamental importance, not only for these investigations but also for electrical prospecting in general, to know the electrical properties of various soils and rocks. It will be useful, there-fore, to discuss this question with the hope that the general points of view discussed in this paper will perhaps be, completed by further observations and determinations of material from various localities. This paper is based principally on the study of literature, and the purpose is primarily a discussion of the main factors that determine the electrical conductivity of soils and rocks. It will follow, however, that the factors discussed here also frequently decide how far a certain orebody can be regarded as a good electrical conductor compared with the sur-rounding rocks. All-rocks are more or less porous; and the pores are filled with liquids and gases. Their electrical conductivity, therefore, depends on the following factors: 1. The electrical conductivity of minerals composing the rock. 2. Electrical conductivity of the liquid filling the pores. 3. Proportion of the volume of liquid filling pores of the rocks to the solid rock material. 4. Shape of the pores. 5. Arrangement of the particles of gas and liquids. 6. Temperature. Dry minerals, with the exception of certain ore minerals, are complete nonconductors from the point of view of applied geophysics; in the present investigation we deal with rocks which have no conducting minerals, and factor 1, therefore, is not important. The same is true of soils. The liquids contained in soils and rocks in most cases are waters, some-times oil. As oil is a nonconductor of electricity, the impregnating waters will determine the electrical conductivity of soils and rocks.

Jan 1, 1932

By J. B. Goddard

Crystallization of ammonium paratungstate (APT) is frequently the last effective purification step in producing high-purity tungsten. However, crystallizer mother liquors are often several times higher in tungsten than predicted by the solubility of APT. The formation of heteropoly anions, particularly those containing phosphorus and silicon, is largely responsible. Solubility of tungsten in APT mother liquor can be linearly correlated with the concentration of these and other impurities. The problem can be overcome by direct treatment of the crystallizer feed solution with aluminum sulfate. By appropriate treatment, the aluminum hydroxide flocculates and is easily filtered, resulting in a purified low-aluminum crystallizer feed from which high APT yields can be attained.

Jan 1, 1985