In the past, dry machine-made sand was generally stored in the open air, but now it is mainly stored in closed factories or cylindrical silos. Silo storage is a spatial storage method. The advantages are that it occupies less space, is easy to retrieve materials, and can be taken at any time, and the cost of use is low. The disadvantages are that the storage capacity is small, and improper silo construction or use may easily cause segregation of materials. Machine-made sand grade Equipped with equipment such as belt conveyor or bucket elevator. The silos are getting bigger and bigger, and the reliability of the belt conveyor or elevator is getting higher and higher.

Three segregation phenomena of machine-made sand in silo storage:

(1) Feed segregation phenomenon; (2) Storage segregation phenomenon; (3) Discharge segregation phenomenon

01 Feed Separation

Mainly because during the accumulation process of materials in the silo, large-grained stones roll along the cone slope towards the bottom due to their large kinetic energy and small relative rolling resistance, and finally stay around the silo, while small-grained stone powder has less kinetic energy. The relative rolling resistance is large and most of it accumulates at the top of the cone. The result is that most of the stone powder is in the middle, forming a cylindrical powder core, where the relative fineness and coarseness are small, while larger particles of stone form a coarse stone material ring around the cylindrical powder core, which is relatively small. The fineness modulus is larger.

02 Storage segregation

Mainly because as time goes by, there are always certain gaps between large-grained stones that cannot be completely filled. Under the influence of gravity and man-made vibration factors (such as vibrations caused by driving, vibrations caused by construction, etc.), the mechanism The small particles of stone and stone powder in the sand will gradually sink and gradually fill the gaps between the large particles of stone below. From a macro perspective, the phenomenon of small particles of stone and stone powder tending to accumulate at the bottom of the silo is formed.

03 Discharge and separation

The main reason is that large-particle materials are heavier and larger in volume. They require greater support than small-particle materials. Once the support force is insufficient, they will fall first. After falling, their kinetic energy is relatively large, so the rolling resistance is lower. It is relatively small, so it can roll farther than small particles after falling, so it looks easier to fall from the macro perspective.