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Jan 1, 1914

By D. B. McDyre

THE object of this study was to compare variations in slag volumes with tap changes while maintaining all other factors constant. This meant: 1. Same type of heat (Spec. SAE 1030). 2. Same charging material (3500 lb foundry, 4000 lb bought scrap). 3. Same amount of sand by weight to fix slag line. 4. Same method of melting with the exception of tap changes. 5. Same method of weighing slag after each test. The equipment of the Dodge Steel Co. consists of a 132-ton Heroult furnace lined with silica brick, using three 8-in. electrodes and a 2000-kva transformer, with four tap changes. In the melting practice we use a Fischer Carbanalyzer and a Herty viscosimeter and try to standardize all heats by making necessary carbon and slag adjustment before boil to keep all heats as uniform as possible.

Jan 1, 1947

By Edward L. Clark, Garrett A. Muilenburg

THE first record of the discovery of iron ore in Missouri was Marquette's observation in 1673 of brown iron ore, or limonite, in the Mississippi River bluffs just north of the mouth of Apple Creek in southeastern Perry County. There is no record of any attempt to mine or smelt Missouri iron ores until 1815, when the Ashebran furnace was erected at the Stouts Creek shut-in near Arcadia, Iron County. Some limonite was treated in this furnace, the first iron furnace west of Ohio, but most of the ore was hematite from Shepherd Mountain and adjacent deposits. Eight years later, in 1823, the Perry furnace five miles north of Caledonia, Washington County, was constructed to smelt limonite ore. It

Jan 1, 1955

Jan 1, 1959

By Fathi Habashi

Chalcopyrite can be readily leached with HNO3, but the recovery of elemental sulfur does not exceed 50% under the most favorable conditions. Preheating at 500°C in a slightly reducing atmosphere increases the recovery of elemental sulfur to about 65%. Chalcopyrite can also be treated with HNO3 in a pressure reactor at 110°C to solubilize selectively the copper while iron remains in the residue as an oxide. The recovery of elemental sulfur also improved when preheated chalcopyrite is treated in this way. Stainless steel should be an adequate material of construction.

Jan 1, 1974

By H. Firmstone

Deposits of cadmia, or impure oxide of zinc, are of common occurrence in the upper parts of blast furnaces using ores containing zinc, and were very common in the charcoal furnaces of Virginia working the brown hematite ores found near the Cadent black slate. These deposits were known to the old charcoal founders as "sulphur rings," and the characteristic green flame of burning zinc frequently to be seen at the tymp of furnaces working ores containing zinc, was held by them to indicate the presence of a "sulphur fall." When zinc is burning in considerable quantities at the tymp, the

Jan 1, 1879

By L. E. Garner

Aggregate resources should be considered primary factors in urban development. Resource planning is essential because land values, previous construction, or zoning restrictions often preempt exploitation of aggregate deposits within an urban area. Sequential land use practices allow development of area prior to urban development population and aggregate consumption trends in Austin, TX, indicate that substantial quantities of reserves will be lost to future development. Aggregate materials are present in nearby areas. However, a comparison of transportation and reclamation costs indicates that reclaiming land after mineral extraction can be significantly cheaper than transporting materials longer distances.

Jan 1, 1982

By S. R. Krogh

In this investigation, a method to measure the basic characteristics of comminution has been developed. These characteristics are expressed by the three major comminution functions - crushing probability function, energy function, and breakage function. By testing three different minerals, quartz, calcite, and jasper, these three functions are determined. It is shown that the crushing qualities of a material can be valued by three constants which define the two first comminution functions. These two functions give the relation between particle size, probability of crushing, and the energy input.

Jan 1, 1980

By R. D. Coleman, A. E. McIlhinney, C. E. Capes

Problems of unstable operation in continuous balling circuits may be traced to the random generation of seed agglomerates. This has been verified during the continuous operation of a laboratory balling drum with internal recycle described previously by the authors. The cyclical behavior of a balling circuit was also investigated using a simple numerical computer model. Changes are suggested in the design of balling equipment to improve stability.

Jan 1, 1976

By N. J. Olson, G. W. Toop

A regular solution is characterized by a finite molar heat of mixing and entropy due only to ideal or random mixing. The thermodynamic properties of binary regular solutions which exhibit constant atomic coordination number and constant atom-atom intefac-

Jan 1, 1967

By Nick Warren

The problem considered is that of predicting rock physical properties from observations of the structure of the rock. The approach here departs from previous studies in that both the physical properties and structural features are taken as statistical data and the relations between them are cast as statistical functions. This approach I have termed a "quantitative petrostructure analysis". This Paper deals with two aspects of making such a study; parameterizing patterns of topographic features of rock, and characterizing variables to allow correlation studies to be carried out. The principle of a quantitative petrostructure analysis is outlined and illustrated using maps from two samples of Conway granite.

Jan 1, 1982

By J. R. Eickmeier

By E. L. Howard, R. S. Barney back

E. L. Howard (Chief Testing Engineer, Pacific Cement & Aggregates, Inc., San Francisco, Calif.) We have made concrete with all the materials mentioned by Mr. Barneyback, including sawdust. He has highlighted the principal problems and effects found when these light materials are used as concrete aggregate. We can only agree with the inter-relationship he has emphasized between grading, specific gravity and unit weight. Uniformity in these characteristics helps to assure good concrete. Mr. Barneyback says the design of lightweight concrete mixtures "is a complete mystery to most engineers". He is wholly right in his evaluation of our ability generally to put together a concrete using lightweight aggregate. A study of the references he has appended will yield little comfort in the matter of proportioning. Much remains to be done in this area of concrete. We believe Mr. Barneyback has treated the subject, though briefly, in an excellent manner.

Jan 1, 1965

By E. N. Pugh, J. V. Craig

WhILE it has been established that well-defined microhardness impressions can be produced in germanium by room-temperature indentation,1-3 the role of dislocations in the process is the subject of continuing discussion.4-7 Recently, Carroll and ~anaka'

Jan 1, 1969

By Stephen E. Erickson

MORE and more hydrocyclones are being installed in beneficiation plants. This recent rapid increase is of special interest in the history of beneficiation, since development of the hydro- cyclone appears to have swung in a circle. To avoid any chance of confusion, it would be well first to review the accepted definitions. The size of a cyclone is expressed as the diameter of the cylindrical section. Size of the inlet orifice- which may be circular, square, or rectangular- is expressed as a diameter, or as width and length, or as an area (in square inches). The angle of a cyclone is expressed as the total included angle. The overflow or finest classification fraction leaves the cyclone through the vortex finder. The underflow or coarsest classification fraction leaves through the apex opening.

Jan 8, 1957

By Walter Kauenhowen

Germany's crude-oil production during 1937 totaled 3,174,157 bbl., an increase of 1.9 per cent over the 3,112,494 bbl. produced in 1936. According to official published data, and using a conversion factor of 1 metric ton = 7 bbl., the oil production of Germany in 1937 by fields was as follows:

Jan 1, 1938

Jan 1, 1921

By C. A. Stetefeldt

Steam-dRied sulphides, obtained in the lixiviation-process, are now almost exclusively sold to smelters, the old methods of melting (after roasting) in crucibles, or cupelling with lead at the mill, having

Jan 1, 1892

By Henry M. Howe

The present paper aims to present in brief the results of Tetskichi Mukai's* studies of the remarkable changes in the properties of manganese-steel caused by changes in the rate of cooling, together with some inferences of my own. Manganese-steel may vary greatly in composition ; that containing from 10 to 13 per cent. of manganese has hitherto reached the widest use. In this paper I consider manganese-steel of about this composition only. To distinguish common steel from manganese-steel, I speak of the

Jan 1, 1893

By C. M. Weld

The southeastern coast of China, from Ning-Po to Macao, represents an element in the continental mass of Asia which has at practically all times in the remote past exhibited a tendency to rise father than to subside.

Jan 1, 1915