Stone Crushing
The use of stone as a building material in relatively large blocks is recorded in ancient historical records but only within the past 200 years has broken stone in small sizes begun to have extensive use, principally in highway-construction. Tresaguet, in 1764, describing his method for highway construction in France, required the top surface to […]
Clay
The term “clay” is applied usually to certain earthy rocks whose most prominent property is that of plasticity when wet. This permits them to be molded into almost any shape, which they retain when dry. Furthermore, they harden under fire. Clays contain hydrous aluminum silicates—the clay minerals—in appreciable amounts, but aside from this a number […]
Chromite
The minerals that collectively are known as chromite form an isomorphous series of the general formula (Mg,Fe)O. (Cr,Al,Fe)2O3. So wide is the range in chemical composition in this group that chrome ore consisting entirely of the mineral chromite may range from less than 30 pct to more than 60 pct Cr2O3. The most comprehensive published […]
Borax and Borates
Borax a sodium borate and the principal sodium salt of boric acid, has been surrounded with romance and with a certain amount of mystery. Its early history is not entirely known but it has been contended that Marco Polo in his travels in the Orient introduced this material to the West during the Middle Ages. […]
Bleaching Clay
The term “bleaching clay” or “bleaching earth,” as used in the oil industries, refers to clays that in their natural state, or after chemical or physical activation, have the capacity for adsorbing coloring matter from oil. There are three common types of bleaching clays: fuller’s earth, activated clays, and activated bauxite. Composition The raw clays […]
Shaped Explosive Charges
Since the end of World War II interest has been increasing in the use of shaped charges in the mining industry and in other industries using explosives for blasting purposes. Shaped charges employ the principle known as the “Munroe effect,” which was discovered by Charles E. Munroe more than 50 years ago (in 1888). Details […]
Bauxite
Bauxite is known mainly as the ore from which aluminum is smelted but it has large use also in the manufacture of artificial abrasives and as a basis for certain chemical industries. A small amount is used for refractories and for other purposes. Composition Dana and others give the mineral formula of bauxite as Al2O3·2H2O […]
Low Carbon Steel Continuous Casting
Recognition of the benefits to be gained from the continuous casting of molten steel into finished or semifinished products has been given by scientific minds since the very beginnings of steel plant technology. In fact, Sir Henry Bessemer is credited with the first of a long list of patents issued by the U. S. Patent […]
What is the Effect of Oxygen on Molybdenum
Specimens A, B, and C, of 0.040 in. diameter commercial molybdenum wire (Lot FW 13-40) were heat treated in the vacuum furnace. Internal friction studies of these specimens were carried out using a low frequency (approximately 1 cycle per second) torsional pendulum completely enclosed in a vacuum tank. The embrittling effect of small pressures of […]
Agglomeration Flotation of Manganese Ore
Beneficiation of the manganese oxide ores at Three Kids Mine near Henderson, Nev., has evolved over a period of years. Commercial application of the process is on a secure basis, and an effective working hypothesis has been formulated to help solve the problems encountered in flotation. Ore Characteristics: Manganeses in the Three Kids ore occurs […]