Хонинговальные головки

Nitroglycerin, an oily fluid produced by reacting glycerin with nitric or sulfuric acid, was discovered by Ascanio Sobrero, a professor at the University of Turin in Italy, in 1847. Sobrero found “…its properties so unpredictable and frightening that he warned against its use” (DuPont 1980). Other discoveries that were important in formulating high — energy […]

THE ROLE OF SCIENCE Scientists and inventors have long worked to develop and improve size-reduction pro­cesses and machines to solve the engineering challenges associated with grinding. Size reduction-used in every mineral-processing operation—has been a continuing field for scientific inquiry and this has contributed to more efficient size-reduction processes in a number of areas: ■ The […]

The second stage of size reduction in mining was manual crushing of mined rocks to sizes suitable for direct use or further breakage (see Figure 3.16). Manual crushing was widely used until the end of the 19th century and is still used in many regions of the world. By 1900, the nomenclature for hand crushing […]

In these types of crushers, high-velocity impacts are used to break rocks. They work either by hitting rocks with a high-speed hammer (hammer mills) or throwing rocks against each other or against a steel plate (Barmac crusher). Breakage by impact was the FIGURE 5.17 Material flows through the crushing chamber of a cone crusher (SME-AIME […]

The different types of roll mills that have been used for pastes include three-, and even five-roller mills. During the latter part of the 19th century, double-roll mills were adapted for use in the grain, ink, paint, and rubber industries, and they are still used for these purposes. Each application has specific objectives; for example, […]

Balls used in the first compartment are larger than those in the second because much larger particles must be broken. Sizing distributions vary according to clinker character­istics and whether the mill is in open or closed circuit. Some clinkers contain small, hard nodules about 10-15 mm in size that grind slowly and may enter the […]

The improvement in grinding efficiency in a conventional stirred mill, as the media became smaller, led to sand with a particle size of 0.5-0.9 mm being used as the media and the shaft speed increasing from 1,700 to 2,200 rpm. This highlighted the importance of stir­rer design to ensure that there was a uniform energy […]

Reliable initiation of the explosive decomposition of nitroglycerin was a problem from the start. Black powder safety fuses were tested but gave erratic results, so Nobel returned to a detonator that he had patented in 1867 before dynamite was invented. This was a tin capsule containing mercury fulminate that exploded when struck, and when used […]

Peter Ritter von Rittinger Peter Ritter von Rittinger was an outstanding mineral scientist whose equipment inven­tions and mathematical descriptions of unit operations established mineral processing as a modern technology (Steiner 2000; Vozar and Kunnert 1972). He was the first to pro­vide a sound mathematical basis for the physics of wet classification and gravity separa­tion processes, […]

GRINDING GRAINS INTO FLOUR For thousands of years, grinding grains to make flour was the primary application of grinding technology. Beginning in about 100 bc, the development of mills driven by water and wind revolutionized the practice of agriculture. Although the importance of bread is underrated today, it is still the main food in many […]