Comminution

The comminution of solid materials consumes energy. Approximately 65% of the power for the production of cement is consumed in comminution. The comminution energy can be estimated by: • Rittinger's law, which assumes that the energy consumed is proportional to the newly generated surface area; • Kick's law, which related the energy to the sizes of the feed particles and the product particles; • Bond's law, which assumes that the total work useful in breakage is inversely proportional to the square root of the diameter of the product particles, [implying] theoretically that the work input varies as the length of the new cracks made in breakage. • Holmes's law, which modifies Bond's law by substituting the square root with an exponent that depends on the material. Three forces are typically used to effect the comminution of particles: impact, shear, and compression. == Methods ==

cell used to process ores after communition. A mixture of ore and water called pulp [1] enters the cell from a conditioner, and flows to the bottom of the cell. Air [2] or nitrogen is passed down a vertical impeller where shearing forces break the air stream into small bubbles. The mineral concentrate froth is collected from the top of the cell [3], while the pulp [4] flows to another cell. , a kind of grinding. There are several methods of comminution. Comminution of solid materials requires various types of crushers and mills depending on the feed properties such as hardness at various size ranges and application requirements such as throughput and maintenance. The most common machines for the comminution of coarse feed material (primary crushers) are the jaw crusher (1m > P80 > 100 mm), cone crusher (P80 > 20 mm) and hammer crusher. Primary crusher products in intermediate feed particle size ranges (100mm > P80 > 20mm) can be ground in autogenous (AG) or semi-autogenous (SAG) mills depending on feed properties and application requirements. For comminution of finer particle size ranges (20mm > P80 > 30 μm) machines like the ball mill, vertical roller mill, hammer mill, roller press or high compression roller mill, vibration mill, jet mill and others are used. For yet finer grind sizes (sometimes referred to as "ultrafine grinding"), specialist mills such as the IsaMill are used. Trituration, for instance, is comminution (or substance breakdown) by rubbing. Furthermore, methods of trituration include levigation, which is the trituration of a powder with a non-solvent liquid, and pulverization by intervention, which is trituration with a solvent that can be easily removed after the substance has been broken down. ==See also==