In 1830 a patent was issued in United States for a machine …which comprised a wooden box containing a cylindrical drum, apparently made of wood, on which iron knobs or hammers were fastened. The expectation was that this drum, when revolved at 350 rpm, would shatter the rock fed into the box. (McGrew 1950) This […]
Рубрика: The History of Grinding
Tumbling Mills
By the middle of the 19th century, the need for better fine-grinding mills had become apparent. Stamps driven by steam engines had limitations on how fine they could grind, particularly on the size of the screens used to remove the desired product from the breaking chamber and keep the oversized material in the chamber. Querns […]
Classifying Liners
Figure 7.18 shows three types of classifying liners. As clinker grinding mills increased in length, it became necessary to devise a system by which the coarse balls were continually thrown back to where the coarsest particles of ore were at the feed end of the compartment. Hardinge had designed his “tricone” mill for this purpose, […]
BALL MILLS WITH SHELLS MOVING AT HIGH SPEEDS
Vibrating Mills One method of keeping balls in motion so that they will collide and break particles trapped between them is vibration, and a vibrating ball mill was developed and patented in Germany in the 1930s. Vibrating ball mills are either vertical or horizontal and can be used as continuous flow or batch mills, and […]
ANFO: POWERFUL AND SAFE
As Table 10.1 shows, there was a spectacular rise in consumption of ammonium nitrate explosives during the 1960s. This was the start of the ammonium nitrate-fuel oil (ANFO) era in industrial explosives, which is expected to continue well into the future. Ammonium nitrate was made by J. R. Glauber in 1659 (DuPont 1980). Its explosive […]
Friedrich Kick
Friedrich Kick was born in Vienna in 1840. After graduating from the Vienna Polytechni — kum in 1862, he became professor of mechanical technology at the Technical University in Prague, Bohemia, where he worked from 1865 to 1892, including three terms as rector. From 1892 to 1910, he was a professor at the Technical University […]
WIND POWER FOR GRINDING
Historically, the wind has also been an important source of renewable energy for driving grinding mills. “Crude vertical-axis panemones have ground grain in the Afghan highlands since the seventh century” (Gipe 1995). Panemones had walls to direct the wind past vertical sails that were attached to a rotating axle, as shown in Figure 4.7. Windmills […]
Vertical-Shaft Impact Crushers
In hammer mills the impact of a fast-moving hammer on a slow-moving rock causes shattering. It can also be caused by the collision of a rock traveling at high velocity with another rock or a breaker plate. This is the concept of a vertical-shaft impact crusher. FIGURE 5.19 Sectional view of the hammer mill (McGrew […]
FUNDAMENTAL FACTORS COMMON TO ALL TUMBLING MILLS
Regardless of the category, all tumbling mills operate on the same principles: ■ The total weight of the charge in the mill—the sum of the weight of the grinding media, the weight of the material to be ground, and any water in the mill—is a function of the percentage of the volume of the mill […]
Grinding Coal in Ball Mills
Most of the grinding of coal for combustion burners is performed in roller mills, but air — swept dry-grinding ball mills operating in closed circuit with separators are also used. Coal is fed to the ball mill with heated air. The air is drawn through the mill by a fanlocated in the classifying section. The […]