Ore crushing and grinding of the pre-sorting operation. A prerequisite for mineral processing is to make a useful mineral ores reached monomer separation. Monomer due to the existence of useful minerals to the grain size is very small, and sometimes need to ground the ore to less than 0.074 millimeters of 80% fineness, and even more would have to make a useful mineral to reach the monomer separation. From the stope ore block out a large degree, such as open-pit mining for ore block up to 1000 mm, it is up to 1000 mm to the mine to only a few dozen pieces of broken-micron (1 micron = 1 / 1000 mm) of fine-grained, often in several stages to complete. To fragmentation, in the large-scale processing plant generally coarse, medium and small three broken (there are four sections of the used), so that pieces of ore particle size gradually reduced to about 8-25 mm, and then grinding machine to grind . Useful until the mineral grains separated from the monomer to achieve so far.
Grinding is usually a section or two. Crushing and grinding broadly divided into the segments shown in Table 2-2.
It should be noted that Table 2-2 in the crushing and grinding a few paragraphs of the division is relative, it works with the size of the election, the use of crushing and grinding equipment type specifications, the product fineness requirements and other conditions.
Crushing and Grinding division of the number of outstanding paragraphs 2-2
Paragraph do not
Name to the mineral particle size (mm) Product Size (mm)
Rough broken 1500-500 400-125
400-125 100-25 in broken
100-25 25-5 chronology
Coarse grinding 25-5 1-0.3
Fine 1-0.3 0.1-0.074
At present, the ore crushing and grinding of the method is mainly through the role of institutional power, the more common mechanical force to the following five.
A, crushing a two broken face when approaching the squeezing pressure on the broken material. Jaw crusher, roll crusher, cone crusher is the main way to crushing the broken machinery.
B, cleavage is the use of sharp broken tooth wedging materials to the split power broken, the role of centralized power, the occurrence of local fracture in the brittle material to adapt to the broken.
C, the fracture of materials in the inter-face as bear fragmentation concentrated load of two-point (or fulcrum) beam, so that material itself broken folding flexor surface.
D, two broken face peel grinding materials made in the relative motion, shear stress imposed on the material so that the breakdown of materials occurred. This power is suitable for fine grinding of materials.
E, crushing it is to use impact of the broken ore. Impact is instantaneous force acting on the ore. Such as counter-attack crusher crusher impact force is.
Plant used in crushing, grinding often broken at the same time the way some of these combined effects.