Effect of Flotation Air Bubble Size
A search of the literature reveals that no measurements have been made of the forces acting between a small solid particle whose surface is hydrophobic, and an air bubble to which the solid adheres, both immersed in water. Analyses have been made of the forces acting to support a greased solid on the surface of […]
Physical Metallurgists
During the past year there have been a number of significant investigations that have furnished evidence on the driving forces governing grain growth and on the role played by boundary impurities. Thus Burke has shown that in high-purity alpha brass the rate of grain growth in the earliest stages is approximately inversely proportional to the […]
Precipitation in Copper-Beryllium Alloys
The nature of the atomic rearrangement involved in the precipitation of the compound γ-Cu-Be from supersaturated solid solutions of the copper-base alloys has been the subject of two extensive investigations. The precipitate in this alloy system has a rather simple structure; at equilibrium it has a body-centered cubic unit cell with copper atoms on the […]
Vapor Pressure of Silver
The purpose of this study was to measure the vapor pressure of silver as the first step in the determination of activities in silver alloys and to test the limitations of the method adopted. In order to work at low pressures, below 2×10-² mm of mercury, the orifice effusion technique was employed. To shorten the […]
Solid Copper Surface Tension
G. Kuczynski and B. H. Alexander—This paper represents a most noteworthy attempt to evaluate experimentally the surface tension of a solid metal. Because of the great importance of such measurements, any proposed method should receive the closest scrutiny before the results can be considered reliable. The writers think, however, that the experimental results are fairly […]
Fundamentals of Mixing and Agitation
Mixers are being applied with increasing frequency to problems in the metallurgical industries. The increase represents in part the modernization of mechanical equipment used through the application of unitized drives, modern electric motors and speed reducers, and recently developed materials of construction. Some applications have resulted from process changes and the use of techniques for […]
Callow Flotation Cells – Design and Operation
Callow-Type flotation cells, with various modifications, have been employed at the Hayden concentrator since 1917. Other flotation machines, such as matless-air and mechanically agitated types, which have been tested in competition, have failed to handle tonnages or give metallurgical results equal to the modified Callow-type cells on the Ray ores. While experimental work was conducted […]
Cationic Collector for the Flotation of Quartz
The behavior of collectors at the mineral-solution interfaces is usually explained in terms of an ionic adsorption process. Through the distribution of collector ions between the solid surface and the co-existing solution phase the mineral is believed to acquire a water-repellent surface coating. Quartz A —100 mesh ground crystalline quartz was infrasized; the products of […]
How to Select the Correct Classifier
Separating a mixture of particle sizes of material suspended in a liquid medium is by no means an exact science. Selecting machines for individual classifying operations is even more difficult. The plant operator’s own background is of course invaluable, and considerable help may be obtained from technical articles, talks with sales engineers, and handbooks on […]
Crushed Limestone Aggregates for Concrete
The problems encountered in efforts to explain the behavior of limestones, dolomites, and related rocks as concrete aggregate lie on the frontiers between the ignorance of the geologists and the ignorance of the engineers. The mineral composition and textures of the rocks have not been adequately explored and described, and the effects of mineral composition […]