Хонинговальные головки

Several types of single-roll mills have been built in which the solids are broken by being nipped between the rotating roll and a fixed surface. An early single-roll machine was the sledging roll crusher, which was built by Allis-Chalmers in 1911. It was a single-roll toothed crusher that was typical of a family of similar […]

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 […]

The demand for iron, copper, and other strategic metals during World War II was enor­mous, and their resulting production depleted the available reserves of high-grade ores. After the war, large volumes of metals and cement were needed to rebuild industry and infrastructure, and a large increase in grinding capacity was required. In the United States, […]

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 […]

The main cause of accidents was premature explosion. The chemical reaction that gener­ated gas and heat from the decomposition of black powder was best activated by a spark or flame but getting close enough to the charge to apply a flame and escape quickly enough to avoid injury was a distinct skill, as noted earlier. […]

Over the centuries, great technical achievements led to the machines of today, which can grind solid particles at the rate of tens of thousands of tons per day. The evolution of machines from devices driven by one person to immense machines with capacities of many hundred tons per hour driven by motors larger than 20,000 […]

Querns for Grinding Ores Ore breakage in Greek and Roman times was mainly by human muscle power, although cattle mills were introduced about 200 bc. The usual procedure was for rocks to be bro­ken with hammers, large pebbles to be broken in mortars and pestles up to 1.5 m deep and 4 m in diameter, […]

Secondary crushers were not used until the large open-side settings in the huge primary crushers built early in the 20th century made them necessary. The first secondary crush­ers were scaled-down standard gyratory crushers, but they had a tendency to “choke” and their productivity was low, making them inefficient for fine crushing. The growing popularity of […]

In 1848, William Easby was granted a patent for a method of converting fine coal into solid lumps. In his application, Easby made only one claim: “The formation of small par­ticles of any variety of coal into solid lumps by pressure.” In an equally brief description of the process, he mentions, “The utility and advantage […]

Starting in the late 19th century, particularly for grinding in the cement industry, tum­bling mills were built in which a short ball mill was attached to a tube mill to make a single mill with a division head separating it into two compartments. Large balls were charged to the coarse grinding compartment. Worn balls in […]