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. Ball mills 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 mills 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 potentially expensive and can grind mixture particles to as small as 5 nm, enormously increasing surface area and reaction rates. The grinding works on principle of critical speed. The critical speed can be understood as that speed after which the steel balls (which are responsible for the grinding of particles) start rotating along the direction of the cylindrical device; thus causing no further grinding.
Ball mills are used extensively in the Mechanical alloying process in which they are not only used for grinding but for cold welding as well, with the purpose of producing alloys from powders. One of most commonly used mills is the SPEX Mill.
Features Of Ball Mill:
The Ball Mill is made up of feeding part, discharging part, gyre part, transmission part, (decelerator, small transmission gear, generator, electrical control) and so on. The hollow axis adopts the cast steel and the lining can replace , the rotating big gear processes in the way of casting rolling gear. The barrel body is wearable well and bears wearable scaleboard. This machine run steadily and works reliably.
Working principle Of Ball mill:
The Ball Mill is a horizontal rotary drum apparatus driving by gears outside. It is a lattice pattern with two storage cells. The raw materials enter into the first cell of the Ball Millevenly through the quill shaft in charging part.
There are step liner palates or wave liner palates in the first cell which has been loaded various steel spheres of different scales. When rotating, the drum causes centrifugal force that brings the steel spheres to a certain height and then the spheres drop to impact and grind the materials. After the rough grinding in the first cell, the qualified partials will enter into the second cell through a single division plate .There are flat palates welded on the inner wall of the second cell, as well as steel spheres. The materials will be further grinded in it and at last the qualified granularities will be discharged through the unload part. Then the whole process is completed.