Хонинговальные головки

The 20th century ended with the mining and stone industries using the same types of primary crushers that were invented by Blake and Gates and used at the end of the 19th FIGURE 5.24 Typical size-reduction circuit for a cryogenic scrap tire-processing plant (Reschner 2002; reprinted by permission from Recovery Technologies Ltd.) TABLE 5.2 Sizing […]

The background to the flotation process was similar to that for the cyanide process. The reserves of ores containing coarse-grained minerals were dwindling, and ores containing fine-grained minerals—which were difficult to extract by the processes of the time— needed to be mined. The cyanide process was unsuitable for ores containing lead, zinc, and copper, all […]

With the success of primary autogenous milling and feed control at Union Corporation, primary autogenous mills became an accepted feature of Rand grinding practice. The autogenous mill circuits required about 25% more power than conventional circuits using pebble mills, but the smaller crushing circuit meant that there was lower capital investment and reduced maintenance cost. […]

The history of cyclones goes back to 1891 when E. Bretney obtained the first patent (Bretney 1891). The Bretney cyclone was designed with a closed apex for intermittent discharge and was the forerunner to present-day desanders that are used for separating sand from water in pressurized water systems. The Bretney cyclone had a roof entry […]

Advances in drilling and blasting were always hard won, and the work was onerous and dangerous until well into the 20th century. Objectives of blasting during the 20th cen­tury were ■ Before 1960: to make excavation possible ■ 1960-2000: to make excavation efficient ■ After 2000: as part of the overall rock breakage process Much […]

Born in New Jersey in 1872, John Van Nostrand Dorr started work as a laboratory assis­tant in Thomas Edison’s laboratory in Orange, New Jersey, at the age of 16. At the time Edison had become heavily involved in mining and processing low-grade magnetite ores. Thinking that the iron ore deposits in the eastern United States […]

As the world’s population and its demand for minerals continued to grow, it became nec­essary to devise a machine that could crush abrasive ores to small sizes at higher rates and that could be driven using a renewable power source. Enter the stamp mill. Although water-driven trip hammers had been used in China for crushing […]

Roller mills were used in China in the 2nd century for grinding the red mineral cinnabar to a vermillion pigment (Figure 6.1) and for grinding grains for cereal (Figure 6.2), and they are still used for these purposes today (Figure 6.3). In 1449, Pietro Speciale was credited with the development of a three-roller mill in […]

Tumbling mills are built for either continuous or batch operation. In continuous mills, feed enters one end and broken product leaves the other. In batch mills, the material to be ground is charged to the mill, and the mill is closed and run until the material is ground. The mill is then stopped, the load […]

By 1960, autogenous grinding had become reality. Aerofall Mills Ltd. and the Hardinge Company had sold 50 mills worldwide; Dorbyl in South Africa and Allis-Chalmers in the United States had started manufacturing them; and Morgardshammar in Sweden and Tyazhmash in Russia would begin manufacturing them soon. The road had been long and difficult, but the […]