Хонинговальные головки

Size reduction is not only the most ancient technology, it is also the most widespread. It is used in every country and in every industry that involves solid particles. Here are some of the more important applications of the technologies we profile in this book: ■ Breaking wheat grains to separate endosperm from bran and […]

In early human history, rocks used for buildings, monuments, or metal extraction were mined by hand using hammers, levers, and wedges made from stone, wood, or bone. FIGURE 3.14 Hammer and gad mining: (a) 15th-century woodcut (Agricola 1950) (b) 18th — century drawing by Eduard Heuchler showing mining and manual breakage. One exhausted miner is […]

Compared to the gyratory crusher, the cone crusher is characterized by its higher speed and a flat crushing chamber design, which is intended to give a high capacity and reduc­tion ratio for materials suitable for this type of processing. The aim is to retain material longer in the crushing chamber to do more work on […]

The high-compression roller mills used in cement plants in the 1980s were similar in principle to the double-roll compactors built in the 1850s and 1950s, although appar­ently the only compactor used as a high-compression mill at that time was a secondhand unit installed by the Fuller Company in its laboratory as a test unit for […]

In the mid-1890s, lawyers became interested in tumbling mills. In 1891, a patent specifi­cation was lodged with the Imperial Patent Office of the German Reich (Scheibe 1993) in which priority was claimed for the use of solid metal sections rather than screens on the cylindrical part of the mill. The purpose of the invention was […]

Vertical Peg Mills After World War II, Netzsch-Feinmahltechnik GmbH, which had been established in Bavaria, Germany, in 1879 by two brothers to design and build machinery for the region’s ceramic industry, took advantage of the rapid postwar recovery to diversify its product range and built processing machines such as filters, mills, and pumps. Its engi­neers […]

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 […]