There is a specific operating speed for most efficient grinding. At a certain point, controlled by the Mill speed, the load nearest the wall of the cylinder breaks free and it is so quickly followed by other sections in the top curves as to form a cascading, sliding stream containing several layers of balls separated by material of varying thickness. The top layers in the stream travel at a faster speed than the lower layers thus causing a grinding action between them. There is also some action caused by the gyration of individual balls or pebbles and secondary movements having the nature of rubbing or rolling contacts occur inside the main contact line. A ball mill, a type of grinder, is a cylindrical device used in grinding (or mixing) materials like ores, chemicals, ceramic raw materials and paints.
For the most efficient results, the Mill should be at least half filled with grinding media. Some operators prefer to go a little beyond the halfway mark to compensate for wear. There is no objection to this and we have been suggesting a limit of about 5 percent.
Cement ball mill rotate around a horizontal axis, partially filled with the material to be ground plus the grinding medium. Different materials are used as media, including ceramic balls, flint pebbles and stainless steel balls. An internal cascading effect reduces the material to a fine powder. Industrial ball mills can operate continuously, fed at one end and discharged at the other end. Large to medium-sized ball mills are mechanically rotated on their axis, but small ones normally consist of a cylindrical capped container that sits on two drive shafts (pulleys and belts are used to transmit rotary motion). A rock tumbler functions on the same principle. Ball mill manufacturers are also used in pyrotechnics and the manufacture of black powder, but cannot be used in the preparation of some pyrotechnic mixtures such as flash powder because of their sensitivity to impact. High-quality ball mills are...
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