in the 1930s through early 1950s, bond developed a new theory of comminution that introduced an index, called the 'bond work index', which relates power consumption in crushing and grinding to the feed and product size distribution. his theory and index were introduced in a widely cited 1952 journal article.
size reduction of solids crushing and grinding equipment. abstract the unit operation of the size reduction or comminution of solids by crushers and mills is a very important industrial operation involving many aspects of powder technology. it is estimated that mechanical size reduction of rocks, ores, coals, cement, plastics, grains, etc.
energy consumption in crushing and grinding. the energy input to size ore fragments is large. overall reduction, performed in a series of stages may be from an eighty percent feed size passing of 40 cm 15.8 inches to a final product size of 270 to 325 mesh .053 to .045 mm .
the rittinger theory is the older and more widely accepted. in its first form, as stated by p. r. rittinger, it postulates that the useful work done in crushing and grinding is directly proportional to the new surface area produced and hence inversely proportional to the product diameter.
the work required for crushing or grinding a given amount of material may be expressed by the amount of energy of the nature of statical and dynamic compressions given to said material, the work shown by the area of stress-strain diagram multiplied by the volume of the material but this is not the net work required for crushing the material into fragments or separating it into small pieces.
difference between crushing and grinding. it consequently follows that the crushing of a quantity q of ore, consisting of particles of uniform size that will just pass through a screen of m meshes per lineal inch down to another uniform size, such that they will just pass through a screen of n meshes per lineal inch,
crushing is done in three stages, reducing to 80% passing 2 cm 3/4 inch . rod and ball mills take the ore down to an 80% passing size of 60 microns 270 mesh . methodology the bond equation is a useful tool to compare predicted and actual values of energy requirements for each step in taconite comminution. crushing and grinding energy are measured
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different theories of crushing and grinding . different theories of crushing and grinding both crushing and grinding refer to and bond theories are invalid although the appliions of rock mechanics are . more. contact supplier crusher and grinding difference .
from introduction: "the purpose of this bulletin is to discuss the theory of crushing and grinding in relation to present-day discoveries and developments and to consider the various mechanical appliances from a theoretical basis."
mineral processing. the water flushes the feed through the mill. when the mill is rotated, the feed, water and the grinding media is churned with flying tumble . grinding of the feed occurs the kinetic energy of the tumbling load is dissipated as grinding of feed, wearing the mill lining and the media, heat and noise.