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By James A. Barr

THE writer's first experience with flotation was during World War I, in the beneficiation of Alabama graphite schist ores. One plant used a cone with a peripheral overflow; dried ore was distributed by a rotating disk onto the surface of the water. No reagents were added. The flake-graphite film floated along with some fine silica. Dewatering screens separated the flake. Naturally unit capacities were low but results were satisfactory. Minerals Separation mechanical flotation machines were used in another graphite mill. Pine oil was added directly to the head cells, with very good results. All the graphite concentrates from both types of flotation were carefully refined after drying by passing through burr mills, followed by very close sizing on sifters. In March 1927, the writer ran a very successful flotation test on minus 28-mesh, deslimed, Tennessee brown phosphate "sand,"[t] using a mechanical laboratory machine built in the shops of the Anaconda Copper Mining Co., through the courtesy of Ernest Klepetko. The machine was soon converted to a subaeration type, with improved results. This phosphate research program was greatly enlarged and led to the formation of the Phosphate Recovery Corporation. The development of nonmetallic flotation followed rapidly. The first flotation machine for beneficiation of phosphate was installed in January 1928, in a pilot mill, by International Minerals and Chemical Corporation, at Mulberry, Florida. These machines were Minerals Separation, 24-in., subaeration types, with weir control of pulp between cells. The sand bleeders were very small-about 1 ¼ -in. diameter. As the feed contained 15 to 25 per cent plus 28-mesh material, the cells choked up frequently. This was corrected by cutting a 2 by 6-in. bleeder opening above the impellers, at grid level, which short-circuited the coarse fractions directly into the feed of the next cell. The matter of size classification and grinding was a considerable problem, which does not come within the scope of this article. Because of the troubles noted above, cascade-type roughers were installed in the second flotation plant, built about 1930. Experimental cells had been tried in 1928. General plant layout is shown in Fig. I and details of the cascade construction in Fig. 2. The cascade installation in plant No. 2 gave good results and eliminated troubles due to choke-ups and coarse feed. The capacities and metallurgical results equaled those of the modified 24-in. Minerals Separation flotation machines in plant No. I The objections to the cascade installation are the floor space and mill height required. In 1939 an improved Minerals Separation machine was tested in parallel with the cascades. Extensive tests indicated

Jan 1, 1945

HARRY B. BARREN Harry B. Barren, born in Cleveland, Ohio, May 31, 1888, died in Indiana Harbor, Ind., on Mar. 18, 1918. After graduating from the Case School of. Applied Science of Cleveland, class of 1910, he spent a year at the Youngstown, Ohio, plant of the Carnegie Steel Co. and the following two years with the National Tube Co. in Lorraine, Ohio. In 1913, he went to Indiana Harbor as assistant superintendent of the blast furnaces of the Inland Steel Co. Four months later, he was made superintendent. On Feb. 11, 1914, he was married to Miss Anna E. Jones in Cleveland and is survived by his widow and two sons, and by his parents Mr. and Mrs. H. A. Barren, of Cleveland, and a brother Kenneth, a lieutenant in the 309th Engineers, stationed at Camp Taylor, Louisville, Ky. CHAS. H. JOHNSON Charles Harmany Johnson died Dec. 10, 1918, at his home in New Castle, Pa., after an illness of more than four weeks brought about by a complete nervous collapse. He was born near Clinton, Lawrence Co. Pa., July 9, 1870, a son of George W. and Elizabeth A. Johnson. His parents moved to New Castle when he was two years old, where he attended the public schools of New Castle. He then attended Allegheny College, and later Massachusetts Institute of Technology where he graduated as a mining engineer. For a year and a half after completing his work at Boston he was connected with the Mesaba Ore Range in Minnesota, and then returned to New Castle and became associated with his father in the operation of the old sheet mill, which was converted into a tin mill and later sold to the American Sheet and Tin Plate Co. Since that time he has been actively engaged with his father in the limestone business and other industries. At the time of his death Mr. Johnson was general manager of the Pittsburg Limestone Co., the G. W. Johnson Limestone Co., the Lawrence Limestone Co., the Keystone Limestone Co., and the Mahoning Limestone Co., all of which have quarries in Lawrence, Butler, Blair and Armstrong counties and also in Maryland and West Virginia. He was president of the Johnson Bronze Co., the National Stone Co., and the

Jan 3, 1919

Dr. Rausch, from your vantage point as educator, engineer, and corporate executive, what would you say is the most fundamental need that must be satisfied for the continuing welfare of our society, our industry and our profession?

Jan 3, 1977

Joseph William Richards, was born in Oldbury, Worcestershire, England, on July 28, 1864, of English-Scotch parents, Joseph and Bridget (Harvey) Richards. In 1871, he came to this country with his parents. He attended the public schools of Philadelphia, Pa., where his father was a manufacturing metallurgist, and in 1882, graduated from the Central High School with the degree of A. B. The same year he entered Lehigh University, from which he received the degree of A. C. (Analytical Chemist) in 1886; M. S. in 1891, and Ph. D. in 1893. His connection with the university was continuous from 1887 until his death, and he therefore adds another to the list of names of men Prominent in the A. I. 11. E. who have helped to develop Lehigh University to the important position which it now occupies in mining and metallurgical education in respect of world-wide fame. It is fitting to recall in this connection that, Eckley B. Coxe, a fonnder of the A. I. M. E., four times its vice-president,, and president in 1878-79, was literally a pillar of the university for several years prior to his death; Thomas M. Drown, founder, vice-presi(lent, secretary for 11 years, honorary member, and president in 1897, was president of Lehigh University from 1895 to 1904; and Henry S. Drinker, founder, manager, vice-president, and honorary member, was president of the university from 1905 to 1920. Doctor Richards was no less active in both institutions. With the exception of the years 1886 to 1887, when he was superintendent of the Delaware Metal Refinery of Philadelphia, his professional life was devoted to the upbuilding of the metallurgical department of the university, in part through his continuous services as a member of the teaching staff, and in part through the international renown won for the department by his achievevements as author, investigator, expert and rerognizcd authority in metallurgy, especially the metallurgy of aluminum, metallurgical-chemical calculations, and electrometallurgy. He was assistant instructor in metallurgy and blowpiping in 1887; instructor, 1888-90; instructor in metallurgy, mineralogy and blowpiping, 1890-97; assistant professor, 1897--1903; professor of metallurgy, 1903-1921. He died at his home in Bethlehem, Pa., on Oct. 12, 1921, of heart failure. To the A. I. M. E., for a continuous period of a dozen years, his services were equally loyal and effective. He was vice-president, 1910-11, and 1916-17; councilor, 1912; dirctor, 1913-15; chairman of the Iron and Steel Clommittee, 191-1-21; he was one of the framers of the Insti-

Jan 1, 1922

Joseph William Richards, was born in Oldbury, Worcestershire, England, on July 28, 1864, of English-Scotch parents, Joseph and Bridget (Harvey) Richards. In 1871, he came to this country with his parents. He attended the public schools of Philadelphia, Pa., where his father was a manufacturing metallurgist, and in 1882, graduated from the Central High School with the degree of A. B. The same year he entered Lehigh University, from which he received the degree of A. C. (Analytical Chemist) in 1886; M. S. in 1891, and Ph. D. in 1893. His connection with the university was continuous from 1887 until his death, and he therefore adds another to the list of names of men Prominent in the A. I. 11. E. who have helped to develop Lehigh University to the important position which it now occupies in mining and metallurgical education in respect of world-wide fame. It is fitting to recall in this connection that, Eckley B. Coxe, a fonnder of the A. I. M. E., four times its vice-president,, and president in 1878-79, was literally a pillar of the university for several years prior to his death; Thomas M. Drown, founder, vice-presi(lent, secretary for 11 years, honorary member, and president in 1897, was president of Lehigh University from 1895 to 1904; and Henry S. Drinker, founder, manager, vice-president, and honorary member, was president of the university from 1905 to 1920. Doctor Richards was no less active in both institutions. With the exception of the years 1886 to 1887, when he was superintendent of the Delaware Metal Refinery of Philadelphia, his professional life was devoted to the upbuilding of the metallurgical department of the university, in part through his continuous services as a member of the teaching staff, and in part through the international renown won for the department by his achievevements as author, investigator, expert and rerognizcd authority in metallurgy, especially the metallurgy of aluminum, metallurgical-chemical calculations, and electrometallurgy. He was assistant instructor in metallurgy and blowpiping in 1887; instructor, 1888-90; instructor in metallurgy, mineralogy and blowpiping, 1890-97; assistant professor, 1897--1903; professor of metallurgy, 1903-1921. He died at his home in Bethlehem, Pa., on Oct. 12, 1921, of heart failure. To the A. I. M. E., for a continuous period of a dozen years, his services were equally loyal and effective. He was vice-president, 1910-11, and 1916-17; councilor, 1912; dirctor, 1913-15; chairman of the Iron and Steel Clommittee, 191-1-21; he was one of the framers of the Insti-

Jan 1, 1922

By Henry Rumfelt

8.1-1. History and Description of Shovels. The history of excavating machinery is not clearly defined but the machines seem to have been originally developed for dredging activities, principally involving rivers and harbors. The first, as far as can be determined, was a steam "spoon dredge" developed by Grimshaw of Boulton and Watt of Sunderland, England, in 1796. The land machine forerunner of the present-day power shovel was not developed until 1835. It was invented by William Smith Otis, a young partner of a Philadelphia contracting firm by the name of Carmichael and Fairbanks. The moving force behind this invention was the heavy activity in railroad construction. From this early start the power shovel has developed from steam powering to internal-combution-engine powering and to electric powering. In both directions it has developed to its present state of a finely engineered and precision-built tool. Through the interim the railroad-type shovel, about a half-swing arrangement designed especially for making railroad cuts and mounted on rails, was developed. The rail-mounted shovel gradually gave way to the full revolving shovel. It was high on the list in 1912 and was practically extinct by 1927. From the beginning, a few of the small revolving shovels designed primarily for the general contractors' market had found their way into quarry and mining operations. During this same period, the stripping shovel had been introduced-a 2 ½ cu. yd., 100-ton, full revolving stripping machine with a 41 ft boom. Although this shovel was designed especially for stripping, it was also used for heavy-duty, open pit mining service. In 1925 the heavy-duty, full revolving quarry and mine machine was developed. Strip mining shovels evolved through a somewhat separate path. Hand digging plows and mule-drawn slip scrapers were first reported used by Kirkland, Blakeney and Groves near Danville, Illinois for strip mining

Jan 1, 1968

The Committee on Nominations is as follows: Pope Yeatman, Chairman, B. B. Thayer, Henry Landes, Robert J. Grant, F. V. Desloge, Albert Burch, C. K. Leith.

Jan 6, 1919

By T. R. A. Davey

A Survey of current and recent research and developmental work is supplemented by predictions for processes which should be developed over the remainder of this century.

Jan 1, 1970

By Harold C. Price

Prior to Sept. 1, 1928, there had never been constructed what might be termed a long pipe line with electric-welded field joints. A year later more than 2500 miles of electric-welded lines had been completed which varied in diameter from 6 to 20 in., and in length from 50 to 700 miles. This paper discusses methods used on five lines with a total length of about 750 miles. The welding equipment used for the firing line or rolling welds, was 300-amp. generators driven with six-cylinder gasoline engines, and for the bell-hole or tie-in welds, 200-amp. generators driven by four-cylinder gasoline engines. A welding gang consisted of a foreman, 6 to 12 firing-line welders and 2 to 4 bell-hole welders, a mechanic and a tractor driver. Coupons about 1/4 in. thick were frequently cut from completed welds, which showed a cross-section of the weld and an indication of its size and penetration. For tests of tensile strength complete welds were cut out. The tensile strength of 52 welds cut from 420 miles of 12-in. line averaged 50,870 Ib. per square inch. The following results give a fair average of the number of welds made per man per day: on 157 miles of 8-in. line both firing-line and hell-hole welds averaged 15.3—the firing-line average was 21; on 39 miles of 10-in. line the firing-line average was 19.9; on 50 miles of 6-in. line, with unfavorable weather, the average was 17.7; on 424 miles of 12-in. line most of which was welded during the spring, 10.3, and with good weather the average rose to 13 welds per day. The average time for making a complete weld on 12-in. pipe 0.313 in. thick was found to be 30 min. for the rolling weld and 45 min. for tie-in welds. A comparison of costs between electric and gas welding shows that the cost of labor for electric welding is 25 per cent. more than gas, generating cost 61 per cent. less than gas, welding wire 40 per cent. less than gas, and supervision and overhead the same. Estimating 50 per cent, annual depreciation on electric welding equipment, and no depreciation

Jan 1, 1930

Starting on the facing page is a 16-page section giving a picture of SME and its component parts-and what they mean to a prospective member.

Jan 6, 1961

By W. C. Leslie, R. M. Fisher, K. G. Carroll

J. S. Bowles and J. K. Mackenzie (Commonwealth Scientific and Industrial Research Organization, Mel- bourne, Australia)—The authors are to be congratulated for giving the first direct experimental proof that the observed macroscopic strain accompanying marten-site transformations is not necessarily a shear. We

Jan 1, 1953

By Norikazu Hashimoto

SILICIDE coatings on refractory metals are often applied by transporting a silicon halide vapor to a hot metal surface . The coatings are usually grown by solid-state diffusion reaction. The diffusion is often slower than the vapor transport and hence may become rate-controlling.

Jan 1, 1968

By John Wulff, Robert Kamm, M. A. Steinberg

IN a previous paper1 from this laboratory, the development of a lead grid method for exploring the distribution of strain and density within metal powder compacts was described, In that work thin lead foil with rectangular holes cut at regular intervals was inserted with the powder fill, the arrangement pressed and then radiographed to permit measurement of the deformation of the lead grid. Densities at each grid element obtained in this manner were plotted as a function of the die dimensions. From such plots it was, found that the densest part of a compact pressed from one side (the top) is at the top outer region and the least dense at the bottom outer region -of the specimen. The axial density maximum occurs more often nearer the bottom than at the top. As a result of such exploratory measurements, it appeared reasonable to conclude that variations in density could be attributed in the main to die wall friction. Thus compacts of large diameter appeared relatively uniform in density except where the die fill had been uneven. Finally it was found that lubrication of the finely finished die cavity contributed more to magnitude and uniformity of density within the compact than interparticle lubrication. Since publication of the above results, it was found that circular-hole grids could be more accurately made and, when deformed within the powder, more readily measured and analyzed. Much of the former work was repeated and new results which include the effect of lubrication, compact height, pressure, speed of pressing and vacuum pressing are reported in the present paper. CIRCULAR-HOLE GRIDS AND ANALYSES OF RADIOGRAPHS Commercial lead sheet 0.008 in. in thickness was used in all the work reported. The 0.0938-in. diam holes were punched in the sheet on 1/8-in, centers to an accuracy of 0.001 in. The finished grid used contained eight or more holes in a row and from I to 24 rows. The lead sheet was clamped between two pairs of brass strips bolted to a small milling machine table which was itself bolted to a bench in correct position near a vise which held the punch. Travel of the lead grid in two dimensions was controlled by two steel lead screws calibrated in 0.001-in. divisions. A stripper plate was used on the punch to avoid distortion of the lead foil. A high carbon-high chromium (chrocar) one-piece steel die was used throughout the work. The die cavity was 1,125 in. in diam and the clearance between plungers and die wall was 0.001 in, The die was also used for pressing from both ends with two long plungers. Finally, lapping of die and plungers gave a surface whose rms value on an Abbot profilometer was 5 micro-in. The die walls and plungers were, except where otherwise noted, lubricated with a stearic acid suspension in benzene. This was put on in multiple layers and allowed to dry before filling the die.

Jan 1, 1948

By M. A. Steinberg, J. Wulff, R. Kamm

In a previous paper1 from this laboratory, the development of a lead grid method for exploring the distribution of strain and density within metal powder compacts was described. In that work thin lead foil with rectangular holes cut at regular intervals was inserted with the powder fill, the arrangement pressed and then radiographed to permit measurement of the deformation of the lead grid. Densities at each grid element obtained in this manner were plotted as a function of the die dimensions. From such plots it was found that the densest part of a compact pressed from one side (the top) is at the top outer region and the least dense at the bottom outer region of the specimen. The axial density maximum occurs more often nearer the bottom than at the top. As a result of such exploratory measurements, it appeared reasonable to conclude that variations in density could be attributed in the main to die wall friction. Thus compacts of large diameter appeared relatively uniform in density except where the die fill had been uneven. Finally it was found that lubrication of the finely finished die cavity contributed more to magnitude and uniformity of density within the compact than interparticle lubrication. Since publication of the above results, it was found that circular-hole grids could be more accurately made and, when deformed within the powder, more readily measured and analyzed. Much of the former work was repeated and new results which include the effect of lubrication, compact height, pressure, speed of pressing and vacuum pressing are reported in the present paper. Circular-hole Grids and Analyses OF Radiographs Commercial lead sheet 0.008 in. in thickness was used in all the work reported. The 0.0938-in. diam holes were punched in the sheet on 1/8-in. centers to an accuracy of 0.001 in. The finished grid used contained eight or more holes in a row and from I to 24 rows. The lead sheet was clamped between two pairs of brass strips bolted to a small milling machine table which was itself bolted to a bench in correct position near a vise which held the punch. Travel of the lead grid in two dimensions was controlled by two steel lead screws calibrated in 0.001-in. divisions. A stripper plate was used on the punch to avoid distortion of the lead foil. A high carbon-high chromium (chrocar) one-piece steel die was used throughout the work. The die cavity was 1.125 in. in diam and the clearance between plungers and die wall was 0.001 in. The die was also used for pressing from both ends with two long plungers. Finally, lapping of die and plungers gave a surface whose rms value On an Abbot profilometer was 5 micro-in. The die walls and plungers were, except where otherwise noted, lubricated with a stearic acid suspension in benzene. This was put on in multiple layers and allowed to dry before filling the die.

Jan 1, 1949

William B. Cogswell, member of the Institute since 1872, died on June 7, 1921, at his home in New York City, after an illness of about six weeks occasioned by an infection of the middle car. Mr. Cogswell is survived by his wife, Mrs. Cora Brownell Cogswell; a son-in-law, and three grandchildren. His first wife died in 1877. William Cogswell was born at Oswego, Sept. 22, 1834, and was taken to Syracuse by his parents when he was four years old. He attended Hamilton Academy and private schools in Syracuse and Seneca Falls. In 1843, he visited England with his parents and brought back a set of drawing instruments, which led to a series of lessons in architecture under Luther Gifford, the only architect in Syracuse at the time. The boy drew many building plans and one set was used for the old Globe Hotel in Syracuse, erected in 1846 and 1847. In 1848, when only 14, he spent a year with a party that was surveying the route of the Syracuse & Oswego R. R. and relaying the tracks of the Utica & Syracuse R. R. He studied civil engineering at the Rensselaer Polytechnic Institute, Troy, for three years, but left that institution in 1852 without receiving his degree. Many years later, in 1884, the degree of C. E. was conferred upon him. During the three years following 1852, Mr. Cogswell served as an apprentice in machine shops at Lawrence, Mass., under the superintendence of John S. Hoadley. About 1856, he was made manager of the machinery department of the Marietta & Cincinnati R. R., at Chili-cothe, Ohio, and three years later became superintendent of the Broadway foundry at St. Louis, Mo. In 1860, in Syracuse, Mr. Cogswell was associated with William A. and A. Avery Sweet in the formation of Sweet Bros. & Co., which later became the Whitman & Barnes Mfg. Co. At the outbreak of the Civil War, Mr. Cogswell received a civilian appointment as mechanical engineer in the United States Navy. During 1860 he was located at Port Royal, S. C., having general supervision over the work of fitting up repair shops at five widely separated stations on the Atlantic seaboard and Gulf of Mexico. In this year his genius and resourcefulness were notably shown. He literally launched a naval machine shop, so that warships could be repaired without leaving, and thereby weakening, blockades against Southern ports. The machine shop was assembled by Mr. Cogswell and shipped by boat to Port Royal. There an old whaler was made over for machine shop purposes and Mr.

Jan 1, 1922

William B. Cogswell, member of the Institute since 1872, died on June 7, 1921, at his home in New York City, after an illness of about six weeks occasioned by an infection of the middle car. Mr. Cogswell is survived by his wife, Mrs. Cora Brownell Cogswell; a son-in-law, and three grandchildren. His first wife died in 1877. William Cogswell was born at Oswego, Sept. 22, 1834, and was taken to Syracuse by his parents when he was four years old. He attended Hamilton Academy and private schools in Syracuse and Seneca Falls. In 1843, he visited England with his parents and brought back a set of drawing instruments, which led to a series of lessons in architecture under Luther Gifford, the only architect in Syracuse at the time. The boy drew many building plans and one set was used for the old Globe Hotel in Syracuse, erected in 1846 and 1847. In 1848, when only 14, he spent a year with a party that was surveying the route of the Syracuse & Oswego R. R. and relaying the tracks of the Utica & Syracuse R. R. He studied civil engineering at the Rensselaer Polytechnic Institute, Troy, for three years, but left that institution in 1852 without receiving his degree. Many years later, in 1884, the degree of C. E. was conferred upon him. During the three years following 1852, Mr. Cogswell served as an apprentice in machine shops at Lawrence, Mass., under the superintendence of John S. Hoadley. About 1856, he was made manager of the machinery department of the Marietta & Cincinnati R. R., at Chili-cothe, Ohio, and three years later became superintendent of the Broadway foundry at St. Louis, Mo. In 1860, in Syracuse, Mr. Cogswell was associated with William A. and A. Avery Sweet in the formation of Sweet Bros. & Co., which later became the Whitman & Barnes Mfg. Co. At the outbreak of the Civil War, Mr. Cogswell received a civilian appointment as mechanical engineer in the United States Navy. During 1860 he was located at Port Royal, S. C., having general supervision over the work of fitting up repair shops at five widely separated stations on the Atlantic seaboard and Gulf of Mexico. In this year his genius and resourcefulness were notably shown. He literally launched a naval machine shop, so that warships could be repaired without leaving, and thereby weakening, blockades against Southern ports. The machine shop was assembled by Mr. Cogswell and shipped by boat to Port Royal. There an old whaler was made over for machine shop purposes and Mr.

Jan 1, 1922

By Albert F. Schneider

The peculiar conditions under which lead and silver ores are now smelted in Salt Lake Valley, Utah, render it advantageous to make slags that are siliceous and carry a high percentage of lime. The ores treated come from Utah, Idaho, Montana, and Nevada; nine-tenths coming from Utah. These ores are siliceous, and contain but little fluxing material; the iron present scarcely sufficing for the sulphur and arsenic. Formerly ores high in iron were furnished from Cottonwood Canons, but this supply is meagre. The ores from Idaho, Montana, and Nevada are high grade galenas, more or less impure. They generally require a large amount of iron for the sulphur, arsenic, and antimony. In the winter and spring of 1880—'81, we were treating at the Germania Works principally Bingham Canon lead ores and silver ores from Tintic. The former contained 15 to 30 per cent. silica, and only 4 to 5 per cent. iron (generally as iron pyrites); they ranged high in lead and low in silver, and carried more or less alumina; the lead was present chiefly as carbonate. The silver ores from Tintic contained sulphides, and ran as high as 80 per cent. silica. We had been running on a slag approximating 40 per cent. FeO, 20 per cent. CaO, 10 per cent. other bases, and 30 per cent. SiO2, which had heretofore been very satisfactory; but with the class of ores then coming in it was of the utmost advantage to use less iron and more lime, especially as the iron ore (50-55 per cent. iron and 5-7 per cent. silica) cost four times as much as the limestone (50-55 per cent. lime, 3-5 per cent. silica). The large amount of alumina in the slag influenced them for the worse; the addition of lime to the charge helped them, and after many experiments regarding the proportion of FeO, CaO, and SiO2, a slag approximating 35 per cent. FeO, 25 per cent. CaO, 5 per cent. other bases, and 35 per cent. SiO2 seemed to answer

Jan 1, 1883

By Wilber Stout

In Ohio, the annual output of coke made from native coals has averaged not more than 70,000 tons, or about enough to run a 200-ton blast furnace. Raw coal locally mined from the Sharon, or No. 1, bed was used for iron smelting in Mahoning furnace at Lowellville, Mahoning Co., as early as 1846. This practice was continued in the Youngstown district until the coal became scarce and the Connellsville coke more popular. At present, the Sharon bed contributes a part of the fuel for the production of ferrosilicon iron at Jackson, Jackson CO. About one-third native coal and two-thirds soft coal are used. In this state, coke, on a commercial basis, was first made in Jefferson County probably about 1861 or 1862. The coals used were the Steuben-ville Shaft, or Lower Freeport, and the Strip Vein or Middle Kittanning. The practice, however, was discontinued before 1880 because of the competition of superior foreign cokes. Beehive ovens, later built at Leetonia, Columbiana Co., were operated for only a few years; the coal used at this place is the Lower Kittanning or No. 5. In a desultory way, slack from the Pittsburgh coal has been coked at a few places in eastern Ohio, and attempts, either for experimental or for commercial purposes, have been made in other parts of the state. Small quantities of coke were made from the Upper Freeport coal at Salineville, Columbiana Co., and near Nelsonville, Hocking Co.; the results were poor. Tests were made of the Middle Kittanning coal near Zanesville, Muskingum Co., at Moxahala Furnace, Perry Co., and at Washington Furnace, Lawrence Co.; the cokes were all high in sulfur and ash. Attempts were made to coke the Clarion coal at Vinton Furnace, Vinton Co.; a small battery of molding ovens and a pile of high-sulfur coke yet remain to tell the story. The Pittsburgh coal was coked on a commercial scale at Utley and at Lathrop, Athens Co., but the operations were not successful and were soon abandoned. These failures and indifferent successes are not to be attributed to a lack of demand for a first-class coke, as Ohio has held a commanding place for many years in iron smelting; nor to a deficiency of coals, as the state has a vast reserve of such material. They are to be ascribed to the inferior quality of the native products offered to the trade. The cokes

Jan 1, 1920

By Dilip K. Das, Douglas T. Pitman

ONE of the major uses of barium in metallic form is as a getter material in vacuum tubes. Because of the high chemical reactivity of the metal, Ba-Al alloys are extensively used. Numerous methods for the preparation of Ba-Al alloys have been published, a few of which1-4 are cited here. Most of these methods were found to be quite elaborate, involving the reduction of BaO, and not too well adapted for the close control of the final composition of small amounts of alloys prepared for laboratory use. A simple laboratory method for the preparation of Ba-A1 alloys in small batches starting from pure metals was devised, so that it was possible to control the desired compositions to within 1 pct. The pertinent features of the alloy system Ba-Al5 are 1) an intermediate compound BaAl, with the melting point of 1050°C, and 2) a eutectic between aluminum and BaAl4 at 98 pct Al. The accompanying sketch shows the experimental arrangement for the preparation of the alloys. Weighed amounts of aluminum and barium were placed in an alumina and a stainless steel crucible, respectively. According to the supplier's specification, the purity of the metals used in the alloys is as follows: a) aluminum rods—99.9 pct Al, and b) barium rods—99.5 pct Ba. The stainless steel crucible, tapered at the bottom and having a 1/16 in. diam hole, rested on top of the alumina crucible. The assembly was placed inside a graphite sleeve which rested on a refractory platform. The platform moved the assembly up and down through the field of a radio frequency coil. A glass bell jar was placed between the crucible assembly and the radio frequency coil to maintain a steady flow of helium around the melt. A small window was cut out on the wall of the alumina crucible to observe the progress of the re- action and to record the temperature with an optical pyrometer. The platform was first raised high enough to move the barium out of the radio frequency coil field in order to allow only the aluminum to melt. The assembly was then lowered so that the barium began to melt and flow out through the small orifice into the molten aluminum. In order to keep the violence of the exothermic reaction under control, the rate of flow of barium was carefully regulated by raising or lowering the crucible assembly. All the samples prepared by this technique were examined by a Norelco X-ray diffractometer using CuKa radiation, The diffraction specimens were prepared by placing the finely powdered samples in flat specimen holders. The Ba-Al alloys prepared with a high barium content were found to consist mainly of BaAl4. The structure of BaAl4 has previously been reported by Alberti and Andress.8 They found that BaAl4 was body-centered-tetragonal with an a0 = b0 = 4.530Å and c0 = 11.14Å. An alloy whose composition was found by chemical analysis to be almost 100 pct BaA1, was used to determine the relative intensities. The d-spacings were obtained from the same alloy to which a small amount of tungsten had been added as a calibrating material. Accurate values for a, and c, were calculated according to the method proposed by Taylor and Floyd.' The calculated values are: a, = b, = 4.566Å and c0 = 11.250Å. The measured d-values for BaAl4 are shown in Table I along with relative peak intensities above background and hkl indices. Acknowledgment The authors are grateful to L. J. Cronin, the head of the Techniques Dept., for suggesting the problem and for his constant interest. References 1Froges and Camargue: German Patent No. 809107, 1951. French Patent No. 935324, 1949. 2E. Bonnier: Annales de physique, 1953, vol. 8, pp. 259-312. 3M. Orman and E. Zemhela: Prac Institute of Metals; 1952, vol. 4, pp. 437-445. 4E. Fujita and H. Yokomizo: Reports Gov. Chemical Industrial Research Institute, Tokyo, 1952, vol. 47, pp. 291-297. 5E. Alberti: Ztsch. fur Metallkunde, 1934, vol. 26, p. 6. 6E Alberti and K. R. Andress: Ztsch. fur Metallkunde, 1935, vol. 27, p. 126. 7 A. Tnslor and R. W. Floyd: Acta Crystallographica, 1950, vol. 3, p. 285.

Jan 1, 1958

By E. J. Freeh, W. E. Horst

Mathematical models of a continuous comminution process are developed as an extension of the batch grinding model. Pilot-scale experimental work is described and the results are used to demonstrate the capability of the comminution models to simulate observed behavior over a relatively wide range of process variables.

Jan 1, 1973