Initiation Methods The History of Grinding

An initiation system starts the detonation of the main charge, after which firings should occur at the exact times that are planned to ensure best results. As discussed earlier, the objective of initiation systems during the black powder and dynamite eras was to improve the safety of explosives. By 1900, the first electric delay detonator Read more

Rotary Querns The History of Grinding

Mortars and pestles and saddlestone mills had several problems: the exhausting motions required of the operator, the batch nature of the processes, and the unnecessary rebreak­ing of particles that were already small enough. The invention of the rotary quern, prob­ably around 600 bc (estimates of the date of its appearance vary by several hundred years), Read more

Classifiers The History of Grinding

In conventional dry roller mills, air is used to transport the particles from the grinding table to the classifier inlet and through the classifier, which is built into the mill housing. The fan and air transport system can take as much power as the mill, and this is shown in the power data (see Table Read more

HIGH-SPEED COLLOID MILLS The History of Grinding

The first mill for making particles about 1 pm in diameter was invented by Herman Plau — son at his research institute in Hamburg in 1913 with the intention of making colloidal FIGURE 8.3 Plauson-Block colloid mill (Forster and Reilly 1922) coal, although it was 1922 before it was used in industry. Within a few Read more

ACKNOWLEDGMENTS The History of Grinding

Our colleagues—some of whom we have known for many years and some we have come to know recently through e-mail—have responded most generously to our requests for information and comments. We are grateful for all the assistance we received. We would like to extend our particular thanks to those colleagues who wrote or contributed to Read more

Cornish Rolls The History of Grinding

In Cornwall in 1804, John Taylor at Wheal Travistock set up two discarded pump barrels in parallel (Barton 1961) as horizontal rolls to crush copper and tin ores for concentra­tion by gravity. This experimental crusher, which became known as “Cornish rolls,” was driven by a steam engine (Figure 5.8). The rolls were only one of Read more

TUMBLING MILLS FOR MAKING CEMENT The History of Grinding

By 1890, 100 Krupp-Grusonwerk tumbling mills were operating in cement plants, and other companies were manufacturing them. One company that contributed much to the technology of tumbling mills was F. L. Smidth and Co. of Denmark. This company had been established as a one-man consulting engineering business by Frederik Laessoe FIGURE 7.5 Transporting an early Read more

AIR CLASSIFIERS The History of Grinding

The classification of very fine particles is carried out in many industries in air rather than water to avoid problems with chemical reactions of particles with water and with separa­tion of ultrafine particles from water and drying them. Some of the disadvantages of dry classification are that it requires ducts and processing equipment that are Read more

Fred Bond The History of Grinding

Fred Bond was the engineer who did much to define the relationship between ore hard­ness, tonnage processed, size reduction achieved, and power required. Born in 1899 and raised in a rural community near Golden, Colorado, he attended and graduated with honors from the Colorado School of Mines (CSM) with a bachelor’s degree in metallurgy. He Read more

Coal Crushers The History of Grinding

The main uses of coal are as fuel in furnaces and as a chemical to reduce iron oxides to iron. To meet environmental standards for these purposes, coal needs to be mined, crushed, separated by size, upgraded, and ground to burn efficiently with the gaseous and solid wastes. Ground limestone is also required to remove Read more