Stone crushers produces different sizes of sand and gravels from large piece of stones, the sand and gravels will meet different construction requirements of railroad, highway, expressway, airport, buildings and other projects. Understanding the specifications of the finished material can provide the necessary reference for users to select the correct crushing equipment.
1. Stone standard according to the particle size
The stone particle size is usually between 5mm and 31.5mm as stated in the mining industry, typically as follows:
1. 5-1 stones represent 5-10mm crushed stone.
2. 1-2 stones represent 10-20mm crushed stone.
3. 1-3 stones represent 16-31.5mm crushed stone.
4. 2-4 stones representing two-four divisions, international standard of 1/4-1/2 inch, indicating 10-15 mm crushed stone.
5. 4-6 stones represent four-six divisions, the international standard is 1/2-3/4 inch, indicating 15-20mm crushed stone.
Because the size of the stone is not uniform, a grade range is needed during the vibrating screen separation, this 1-2, 1-3, 2-4 refers to this range, the unit is centimeters, such as 1-2 is the diameter within this range of crusher stones is 1 cm for minimum size, and 2 cm for maximum size. Of course, the range refers the majority of the crushed stones, it does not represent all of them.
2. Sand standard according to the particle size
Refer to the standard of construction sand in China, sand refers to the rock debris with particle size less than 5mm, formed and accumulated in natural conditions such as lake, sea, river, mountain, etc. It can also be the particles less than 4.75mm processed by mining machinery. The coarseness of sand is divided into 4 grades according to fineness modulus.
1. Coarse sand, fineness modulus of 3.7-3.1, with an average particle size of 0.5mm or more.
2. Medium sand: fineness modulus of 3.0-2.3, with an average particle size of 0.5-0.35mm.
3. Fine sand: fineness modulus is 2.2-1.6, average particle size is 0.35-0.25mm.
4. Extra fine sand: fineness modulus is 1.5-0.7, average particle size is 0.25mm or less.
3. Other standard specifications of sand and gravel
1. Needle, flaky particles
The length of the stone particles is 2.4 times greater than the average particle size is called needle particles; thickness less than 0.4 times the average particle size is called flake particles.
2. Mud content
The content of particles in the stone which is less than 75um particle size.
3. Mud block content
Crushed stone in the original particle size greater than 4.75mm, by water immersion washing, hand kneading less than 2.36mm particle content.
4. Stone powder content
Stone powder refers to the rock particles with particle size less than 0.075mm or 75 microns.
The ability of sand and gravel, especially stone, to resist rupture under the action of natural weathering and other external physical and chemical factors.
In addition to particle size and shape specifications, various industries have corresponding requirements on the needle-like particles, mud content, clay content, stone powder content and firmness of sand and gravel materials, so the requirements should be clearly defined in advance when configuring the stone crusher plant production line, this will not affect the quality and sale of the finished materials.