Search Documents

By Theron Wasson

Michigan's production of 17,301,000 bbl. in 1945, which is in line with previous years, has been maintained by extensions to old fields like Deep River, Adams, Fork, and others. There were a number of new discoveries but, as in the past, these are not given very much importance because enough drilling has not been done to develop their potentialities; however, judging by the past, some of them will develop enough production so that 1946 -will probably be in line with other years. Activities in Michigan were confined to the Basin area of the lower Peninsula, which has been under development since 1925.

Jan 1, 1946

By J. H. Wernick

IN a study of the rate of decomposition of %-in. cubes of limestone, dolomitic limestone, and dolomite in a sweeping nitrogen atmosphere, Joseph, Beatty, and Bitsianes' found that the zone of calcination advanced at substantially a constant rate at a given temperature. The purpose of this paper is to show that their data indicate at least two processes occurring when the above carbonates decompose. It is suggested that there are two processes occurring consecutively, one the limiting process in a given temperature range and the other the limiting process over another temperature range. The data of Joseph and co-workers have been extended by use of the Arrhenius equation, Eq. 1, a relation beween the velocity constant k of a reaction and the absolute temperature T. d In k A ' dT Rr2 A is the activation energy in calories per mol (additional energy that must be added for an average molecule to react), and R is equal to 1.986 cal

Jan 1, 1955

By B. DE MARE

THE No. 6 open-hearth furnace at the plant of the Worth Steel Co., Claymont, Del., is the first to be rebuilt according to the Kuehn system. This as well as the other five furnaces at Claymont, has a nominal capacity of 75 tons, but the actual charge is about 242,000 lb. No hot metal being available, the pig-iron is charged cold. Oil of low grade with an asphalt base is used as fuel. These two items have to be kept in mind when discussing the actual fuel consumption. Careful records have been kept covering a five weeks run and the following is a brief summary of them The time required to heat the furnace preparatory to charging from the time a wood fire was started until charging commenced was 36 hours. This, I understand, is much less than with furnaces of standard design. The draft of the furnace, as shown by a gage in the stack-flue, is 1.25 in. The maximum draft with new checkers on former runs was 1.50 in., this draft gradu¬ally decreasing as the checkers closed up. Both of the first helpers claim the present draft is all they need for the proper working of the furnace, and, as with the Kuehn regenerators the draft remains practically the same from beginning to end of a run, this is satisfactory.

Jan 1, 1929

By Bernard MacDonald

Introduction. OF the treatment of the slime-pulp of gold- and silver-ores by cyanidation, agitation is an essential part. When prepared for treatment, this pulp, consisting of ore reduced to such fineness that approximately 80 per cent. of it will pass through a 200-mesh screen, is mixed with a certain proportion of water, carrying in solution the quantity of cyanide (KCN) and other chemicals required. The water-constituent of the pulp thus prepared usually ranges from 1 to 2 parts by weight to 1 of the dry ore. Thus constituted', the pulp is charged into treatment-tanks, the shape and capacity of which vary, according to the quantity of pulp to be treated daily and the method of agitation to be employed. Tanks have no other function in a cyanide-plant than that of being economical and convenient containers or receptacles for holding the pulp, solution, or water used in the operations. It is by agitation that the solids in the pulp charged into the tanks are kept in suspension in, and mixed with, the solution in the proper proportions required for the treatment. If the proper mixture of solution to solids be determined to be 2 to 1 by weight (which is, approximately, 5 to 1 by volume), this proportion should be maintained in every part of the charge ; -that is, each solid particle of the pulp, whether it be of 180- or 400-mesh size, should, be surrounded by five times its own volume of solution throughout the whole period of treatment. The reason is, that the amount of chemicals ascertained to be necessary for dissolving the gold and silver contained in the solids, is held in uniform solution in the water-constituent of the pulp, and, therefore, the determined proportions of solution and solids must be maintained at all times during treat-

Apr 1, 1912

ALABAMA Aldrich -Thomas, D A Altoona -Cain, J Anmston-Cowie, L K Walmsley, W N White, H E Bankhead -Terentieff, V E Bessemer -Abbott, C E Ball, E M McKenzie, W C, Jr Mitchell, F R Morgan, C Thompson, N E Birmingham -Adams, J H Adler, J E Aldrich, T H Aldrich, T H , Jr

Jan 1, 1923

ALABAMA Altoona -Cain, J Anniston-Cowie, L K Hermrod, A A White, H E Bessemer -Abbott, C E Ball, E M Mitchell, F R Thompson, N E Birmingham -Adler, J E Aldrich, T H Aldrich, T H, Jr Blackburn, A R Bush, M W Clark, G H Cowrn, P G Crane, W R Crawford, G G Crockard. F H

Jan 1, 1923

By Homer W. Riley

ANTHRACITE SMALL power-driven, toothed, cast-iron rolls were used first to break anthracite in 1844. Prior to that time, men with hammers, who stood on perforated cast-iron plates, broke the large lumps into commercial sizes. In order to convert run-of-mine into the various sizes required by the anthracite industry, about 20 million tons must be broken, annually, into smaller sizes. This phase of anthracite preparation is of major importance, because the degradation accompanying reduction in coal sizes should be kept at a minimum. The exclusive use of toothed rolls for that purpose indicates that comminution by rolls is the best solution of the problem. Many improvements have been made in tooth design, but the most important was a reduction of the peripheral speed of the rolls from 1000 to 300 ft. per minute. The higher speed was based upon and approximated the velocity of a falling piece of coal when it entered the rolls, Exhaustive roll tests at the slower speed showed that the same size reduction could be affected with less degradation. The adoption, therefore, of slow-speed, compound geared rolls, especially for breaking the larger sizes, became quite general after 1912. A high-speed roll is shown in Fig. 1 and a slow-speed roll in Fig. 2. Anthracite Crushing Problems.-Crushing anthracite presents the problem of selecting a series of rolls that will produce the greatest percentage of the prepared sizes of nut and over. The size distributions to be expected are shown in Table 1. Coal breaking and crushing practices in anthracite breakers involve the use of equipment for comminuting the following classes of material: 1. Run-of-mine-plus 6 ½ -in. coal. 2. Sized coal-steamboat, broken, egg, stove, nut, and pea. 3. Flat coal--coal that is flat and hence not suitable for the market. 4. Bone--a piece of laminated coal and slate, crushed for the purpose of reclaiming the coal. 5. Breaker refuse, reduced to a size suitable for flushing into a mine for back-filling purposes.

Jan 1, 1950

By H. H. Stoek, G. W. Harries

The term " Anthracite Coal-Field " is generally used to refer to a comparatively small territory lying in the eastern-central part of Pennsylvania. This territory includes about 3,300 sq. miles of area, located chiefly in five counties in which anthracite-mining is the dominant industry. Although an area of 3,300 sq. miles is embraced in the region, less than one-fifth of this area, or only 484 sq. miles, is underlain by workable coal-seams. Moreover, this prorluctive portion is not a continuous area, but consists of a number of detached basins. These are known as the Northern, containing 176 sq. miles; Eastern-Middle, containing 133 sq. miles; Southern, containing 181 sq. miles; and western-Middle,containing 194 sq. miles. From the standpoint of business and trade, the region is divided into three districts, known as (1) the Wyoming, which includes the Northern field and the small Bernice basin; (2) the Lehigh region, which includes all of the Eastern Middle field and that part of the Southern field east of Tamaqua; and (3) the Schuylkill region, which includes the WesL ern-Middle field and that part of the Southern field west of Tamaqua. The relative commercial importance of these districts at the present time is shown by the coal-shipments as given in the following table :

Jan 1, 1904

By A. A. Smith, J. S. Smart

THe elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses. When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range o to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorilv determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing 2nd oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B, and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold. The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300' and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type. All samples were quenched from the annealing temperature in 10 per cent H²S04 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.' Effect of Silver Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By A. A. Smith, J. S. Smart

THe elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses. When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range o to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorilv determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing 2nd oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B, and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold. The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300' and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type. All samples were quenched from the annealing temperature in 10 per cent H²S04 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.' Effect of Silver Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By F. W. Glaser

Iron-silicon alloys have had a great influence, in many ways, in modern industry. Silicon steels have been used almost exclusively for the construction of electrical machinery, but have also become an important material for structures which benefit by the high tensile and yield strengths of this material. In elaborating on the early history of work done on iron-silicon alloys, Greiner, Marsh and Stoughton1 went back as far as 1808, and pointed to Berzelius as the first producer of ferrosilicon. During the last twenty years some very important contributions in the form of studies of the iron-silicon system, as well as of the physical properties of these alloys, have been published. In consideration of the brit-tleness and poor machinability of alloys containing more than 5-6 pct Si, commercial interests have stimulated the research done on iron-silicon alloys, but mainly in the range of 0 to 6 pct Si. Yensen2 has shown the influence of im- purities, such as carbon, sulphur and phosphorus on the magnetic properties of 2, 4, and 6 pct Si alloys. Corson3 extended his investigation of physical properties to approximately 32 pct Si, and attributed the brittleness of the high-silicon material to the particular constitutional features of the alloys. Though mentioned earlier in the literature, the effect of nitrogen on crystal growth and magnetic permeability of iron-silicon alloys has been demonstrated recently by Morrill4 and Rostoker,5 respectively. In all the above quoted investigations, except that of Rostoker,5 sand or chill casting processes were employed for the preparation of samples. A major advantage of the powder metallurgy process is that it does away with time-consuming machining in many applications. The powder metal industry is always interested in pro- ducing a finished product employing a material which has presented considerably greater difficulties in manufacture by other methods. Steinit26 described preparation and testing of various Fe-Si alloys which were produced by the powder metallurgy process for the manufacture of armatures for small electric motors or generators. While Steinitz investigated alloys up to 6 pct Si, Rostoker5 went as high as 9 pct Si. The author7 previously discussed the diffusion of iron-silicon compacts containing 6 and 10 pct silicon. It is the object of this paper to study the progress of diffusion occurring in iron-silicon alloys by electrical resistivity measurements. All samples were prepared by pressing and sintering of compacts. Iron, silicon, and Fe-Si powders of various mesh size and compositions were employed to obtain test samples. It was assumed that complete diffusion had been obtained when the electrical resistivity reached a constant value characteristic for that particular alloy. To this end, electrical resistance measurements were used to follow the progress of alloying under various conditions.

Jan 1, 1950

By G. W. Imholz

A number of interesting wells were drilled in north central Texas during 1940. The Shell Oil Company's Smith well in scc. 143, block I, H. and T. C. survey, Stonewall County, was completed for an initial production of 581 bbl. per day from the Mississippian limestone, with a total depth of 6065 ft. The same company's Patterson well, sec. 393, block D. H. and T. C. survey, Stonewall County, tested the Ellenburger limestone and was abandoned as a dry hole with a total depth of 6760 feet. In Nolan County the Tex-Harvey Oil Co. drilled a well in sec. 43, near the Tipton well, which was completed as a small producer in the Strawn section. The Tex-Harvey well tested this producing horizon but was abandoned as a dry hole with a total depth of 5210 feet. The Montour-Haggart well, sec. 184, block 2, H. and T. C. survey, Fisher County, tested the Strawn and was abandoned with a total depth of 5664 feet. The Georgian Oil Company's Blach, sec. 309, T. R. and L.. Shackelford County, encountered the top of the Ellenburger limestone at 4725 ft. After being plugged back to 3915 It. from a total depth of 4825 ft., the well tested 10 bbl, of oil per day and 300 bbl. of water. The W. I. Sothern No. 2 Carlisle well in sec. 293 was deepened to the Cambrian. The top of the Ellenburger was encountered at 6540 fcet. A wildcat well in Fisher County, the E. A. Stephenson-Maberry, apparently opened a new pool when the well encountered sand from 3298 lo 3302 ft. and was completed for 50 bbl. per day in the Cook sand horizon. In Jones County, the King Oil Company's Olsen well, sec. 158, B. B. B. and C. survey, extended the Avoca-Olander pool. The well was completed for 263 bbl. in 8 1/2 hr. from the Palo Pinto limestone, from 3298 to 3302 ft. Ungren-Frazier extended the Akard pool with No. I Akard, in the D. 'T. Bruce survey. The well was completed for 83 bbl. per day from the Cook sand, encountered from 2109 to 2126 feet.

Jan 1, 1941

By G. W. Imholz

A number of interesting wells were drilled in north central Texas during 1940. The Shell Oil Company's Smith well in scc. 143, block I, H. and T. C. survey, Stonewall County, was completed for an initial production of 581 bbl. per day from the Mississippian limestone, with a total depth of 6065 ft. The same company's Patterson well, sec. 393, block D. H. and T. C. survey, Stonewall County, tested the Ellenburger limestone and was abandoned as a dry hole with a total depth of 6760 feet. In Nolan County the Tex-Harvey Oil Co. drilled a well in sec. 43, near the Tipton well, which was completed as a small producer in the Strawn section. The Tex-Harvey well tested this producing horizon but was abandoned as a dry hole with a total depth of 5210 feet. The Montour-Haggart well, sec. 184, block 2, H. and T. C. survey, Fisher County, tested the Strawn and was abandoned with a total depth of 5664 feet. The Georgian Oil Company's Blach, sec. 309, T. R. and L.. Shackelford County, encountered the top of the Ellenburger limestone at 4725 ft. After being plugged back to 3915 It. from a total depth of 4825 ft., the well tested 10 bbl, of oil per day and 300 bbl. of water. The W. I. Sothern No. 2 Carlisle well in sec. 293 was deepened to the Cambrian. The top of the Ellenburger was encountered at 6540 fcet. A wildcat well in Fisher County, the E. A. Stephenson-Maberry, apparently opened a new pool when the well encountered sand from 3298 lo 3302 ft. and was completed for 50 bbl. per day in the Cook sand horizon. In Jones County, the King Oil Company's Olsen well, sec. 158, B. B. B. and C. survey, extended the Avoca-Olander pool. The well was completed for 263 bbl. in 8 1/2 hr. from the Palo Pinto limestone, from 3298 to 3302 ft. Ungren-Frazier extended the Akard pool with No. I Akard, in the D. 'T. Bruce survey. The well was completed for 83 bbl. per day from the Cook sand, encountered from 2109 to 2126 feet.

Jan 1, 1941

By EL HANAF

The exploratory program initiated in Egypt in 1937 by four major oil companies was well under way early in 1939. Extensive gravity-meter surveys were carried out in the Sinai Peninsula and the Eastern and Western Deserts. Seismic and magnetometer work vas conducted on a restricted scale. The data collected justified wildcat drilling on structures located geophysically and/or geologically.

Jan 1, 1946

By A. E. Wells, H. O. Hofman, R. P. Reynolds

A Discussion of the Paper of H. O. Hofman, R. P. Reynolds and A. E. Wells, read by title at the London Meeting, July, 1906 ; presented at the New York Meeting, April, 1907, and printed in Bi-Monthly Bulletin, No. 13, January, 1907, pp. 37 to 52. GEORGE A. PACKARD, Boston, Mass. (communication to the Secretary*) :-The very interesting results obtained by Prof. Hofman and his assistants came to my attention when I had temporarily assumed charge of the metallurgical department of the Missouri School of Mines, and had found it, pending the completion of a new building, lacking a furnace in which to roast ore preparatory to the customary lead blast-furnace run. An attempt at lime-roasting had been already determined upon, but the use of a charge which would make a slag of definite composition was a new idea. The results following were obtained by Messrs. Aubrey Fellows, J. C. Long, E. R. Wash, and Dr. T. C. Tseung, under my supervision. It is regretted that the data are not more complete; but the work was done simply incidentally to securing the desired ore for the blast-furnace, with no idea of obtaining any results of especial interest. It is submitted because of the metallic lead obtained, no notice of which has been seen elsewhere. The ore was an aggregate of several lots of concentrates, apparently from Missouri ores. The analysis follows, with that of the limestone and sandstone used, as far as made:. Ore, SiO2, 3.04; Fe, 0.77; CaO, 2.53; Pb, 68.74; Zn, 5.77; S, 13.9 per cent.; limestone, SiO2, 1.0 ; CaO, 54.35 per cent.; sandstone, SiO2, 99.8 per cent. The converter was made in the shops from a sheet of No. 14 iron riveted in the shape of a truncated cone, 20 in. in diameter at the top, 15 in. at the bottom and 22 in. high. A grate of No. 8 iron, 17 in. in diameter, with 130 s-in. holes placed at about 1.25-in. centers, was held in place by the shape of the

Jul 1, 1907

By Orville R. Lyons

THE removal of moisture from coal has been a coal-preparation problem ever since the first wet-washing preparation plant was placed in operation. Today, when most of the coal produced in the United States is wetted at the working face when mined, or is cleaned by wet methods, the removal of moisture is a necessity for any one or a combination of the following reasons; (1) to avoid freezing difficulties during shipment, (2) to increase the B.t.u. content, (3) to effect savings in freight costs, and (4) to so improve the coal that it may be used for specific purposes-for instance, in the production of briquettes or the production of metallurgical coke-or so that it can be treated by dry cleaning methods. In general, the amount of water retained by coal particles varies with the size-consist of the coal. Fine coal has a larger surface area per unit weight than does coarse coal, so its capacity for retaining moisture is proportionately greater. The removal of moisture from coarse coal is relatively easy, while the removal of water from minus 10-mesh coal or finer is a major problem, usually requiring an individual solution at each preparation plant. As a result, a multitude of methods and a variety of equipment have been designed to solve both general and specific moisture-removal problems. Definitions In order that misunderstanding may be eliminated insofar as possible, it is necessary to define the terms to be used. The moisture content of any given increment of wet, washed coal is made up of two parts, inherent and surface moisture. Inherent moisture has been defined in various ways and as yet no standard definition has been agreed upon. However, in general, it is considered as the moisture that is present in the coal in the bed. The important point to remember is that coal with any amount of inherent moisture, whether 2 or 20 per cent, will appear dry if there is no surface moisture. Also important is the fact that inherent moisture can be removed, in part, by air drying at atmospheric temperatures. Surface moisture is that attached to the surface of the coal particles or that retained in cracks and fissures other than capillary openings in the coal substance. Essentially, insofar as the bituminous coal and anthracite indus-

Jan 1, 1950

Andy H. Vassiliou – Introduction Ladies and gentlemen,.good evening and welcome to the Paul F. Kerr Memorial Symposium dinner. I believe we are all here to honor the memory of a great teacher and advisor, and a true friend -- Professor Kerr, or Dr. Kerr, or to most of us who were his students, "Pappy" Kerr. Most of us who attended the Paul F. Kerr Memorial Symposium earlier today at the New York Hilton had the opportunity to read, or listen to, or discuss scientific papers presented in honor of Dr. Kerr. In addition, all of the speakers had the opportunity to reminisce about their association with Dr. Kerr, who was credited as having contributed substantially to their graduate education and the development of their careers. Dr. Kerr's two daughters -- Ruth and Nancy -- who attended the Symposium at the Hilton are also here with us tonight. I think we should keep tonight's festivities on an informal basis since we are all old friends or former students of Dr. Kerr. Some of us may want to say a few words about our experiences at the time we were students at Columbia, and hopefully include some anecdotes relating to Professor Kerr. I would like to invite everyone to do so, but first we have arranged for two of us to be the lead speakers, whom I will introduce in a few moments.

Jan 1, 1985

By H. O. Hofman

(Canal Zone Meeting, November, 19]0.) THE sudden decease, April 1, 1910, in Chicago, of Dr. Franklin R. Carpenter was a shock to his- many friends. He died in his sixty-second year, of heart paralysis. To most fellow-members of the Institute who have followed the progress of the. last twenty-five years in the mining and treatment of non-ferrous ores, the work of Dr. Carpenter in that line is familiar ; but very few, even of those who knew him well in the later years, are acquainted with his earlier struggles to satisfy an inborn hunger for knowledge. The story of his life resembles that of the pioneer who opens up new country; overcoming hardships with indomitable courage, meeting doubts and difficulties with an alert and open mind, and exercising in the face of reverses an unconquerable perseverance. It seems appropriate to place on record in the Transactions a brief outline of the life and work of this eminent engineer. During the past 15 years of his life Dr. Carpenter was much interested in genealogy. In the pursuit of this study as an avocation, he traced his own ancestry to the time when ?Hugh," called "le Charpentier" on account of the dexterity with which he had swung his battle-axe as a crusader, settled in Sussex on lands received from William the Conqueror. The Carpenters came to this country with William Penn. A prominent member of the family was Joshua Carpenter, the founder of Christ Church, Philadelphia. Dr. Carpenter's branch of -the family moved from Pennsylvania into that part of Virginia which is now West Virginia, where his grandfather settled in Harrison county, while the grand-uncle went further west, and built the first iron-furnace at Hanging Rock, Lawrence county, Ohio. In fact, since early times, the Carpenters appear to have been iron-masters. Franklin R.. Carpenter was born, Nov. 5, 1848, in Parkers-

Aug 1, 1910

Jan 1, 1893

By R. E. Hudrlik, G. W. Preckshot

The diffusion coefficients of silver from solid silver in molten lead were measured to within ± 0.8 pet in a columnar type diffusion cell ower, the temperature range of 326° to 530°C. Fick's law describes the process up to 530°C where the laminar mechanism appareltly breaks down. These is negligible resistance at the interface as shown by mathematical analyses. The diffusion coefficients are found concentration independent. IT would seem that diffusion in liquid metals would be free of such effects as molecular structure, dissociation. polarization. and compound formation. This view was taken by Gorman and preckshot in their study of diffusion of copper from solid copper into molten lead. They reported diffusion coefficients which were independent of the concentration over the range of 478° to 750°C. They found that the Stokes-Einstein equation with constant radius of the diffusing specie represented the diffusion data better than Eyring's rate theory equation and Sheibel's correlation. The radius of diffusion was found to be that of the doubly charged copper. There appeared to be no resistance across the solid-liquid boundary. In the present work the diffusion coefficients for silver in liquid lead were measured over a range of temperatures of 350° to 505°C. The solubility of silver in lead over the range of 303° to 630°C was also obtained. These results are compared with calculated or correlated values or with data in the literature. EXPERIMENTAL Procedure—The experimental equipment techniques and procedures were those reported in detail by Gorman and preckshot9 and will not be repeated here. Measured values of WT, Co, A. L were obtained for various diffusion times and the diffusion coefficient was computed for the case of no resistance at the interface9, 11 by: WT/CoAL = 1- 8/p2 n=1 1/(2n - 1)2 exp[-(2n - 1)2p2 Dt/4L2] [1] or where there was resistance at the interface by: WT = 1- ?n=1 2h2/ap2L [sxp [-Dan2t]/[(h2 + an2) L + h] The roots an are those of the transcendental equation3 tan (an L) = Iz/cun. The diffusion coefficient is that defined by Hartley and Crank.7 The total silver in the lead cylinder and equilibrium slug was determined by a cupellation technique' with proper correction for losses. Analysis of known samples showed that this method is surprisingly accurate. The amount of silver in the lead adhering to the silver cylinder was obtained in the same fashion as shown by Gorman and preckshot.9 The small errors involved in this determination are not critical since the silver in this adhering lead layer is only 3 to 15 pet of the total diffused. Materials—Electrolytic silver containing 99.9+ pet Ag obtained from General Refineries of Minneapolis, Minn. was used for all but runs 7 and 8. For the balance of the runs this silver was reduced with hydrogen at 1100°C and its oxygen content was found to be about 0.017 pet. For the runs. 7 and 8, phosphorous-reduced silver of the same purity was obtained from Handy and Harman Co. of Chicago, Ill. The densities of the phosphorus-reduced silver and the hydrogen-reduced electrolytic silver were 10.484 and 10.487 g per cm3, respectively. These values agree with those reported for pure silver. Silver which was reduced at 900 C had an average density of 9.998 g per cm3, indicating porosity. This silver was used for a number of runs which were not tabulated in Table I. These are indicated by crosses on Fig. 2. The 99.999 pet Pb was obtained from the National Lead Co. Research Laboratory of Brooklyn, New York. DISCUSSION OF RESULTS The diffusion and solubility results are reported in Table I for eleven runs using either phosphorus-reduced electrolytic silver or hydrogen-reduced silver at 1100° C. The solubility data shown in Fig. 1 show the excellent agreement with that reported by Heycock and Neville.8 The data of Friedrichs5 apparently are in error. The experimental solubility data of this work are reported to 0.3 pet. The experimental diffusion coefficients computed from Eq. [1] are reported within 1.2 pet of the mean and are plotted in Fig. 2. These are expressed within +0.8 pet of the experimental values over the entire temperature range by: D= 8.26 x 10 -5 e-1925/RT . [3] There appears to be little difference due to the

Jan 1, 1961