The production process of artificial sand can generally be divided into the following stages: stone feeding – crushing – sand making – screening – powder removal – finished products. The common process flow is as follows:
Artificial sand production process
The whole process involves vibrating feeder, crusher, sand making machine, vibrating screen, sand washing and dust removal equipment, etc. This article will explain the technical requirements and selection principles of the equipment one by one.
Technical requirements of vibrating feeder
The vibrating feeder is located between the feeding silo and the crusher, which can uniformly and continuously feed block and granular materials from the silo to the crusher, and coarsely screen the materials at the same time.
Fote vibrating feeder
When configuring the vibrating feeder:
- 1 Minimize the pressure of the material on the tank. Generally, the effective discharge of the silo should not be greater than 1/4 of the tank width, and the material flow speed shall be 6-18 m/min.
- 2 For a large feeding amount, a high enough bar plate should be set at the discharging place at the bottom of the bin, but the bar plate should not be fixed on the tank.
- 3 The inclination angle of the rear wall of the silo can be 55°-65° for smooth discharging.
How to choose artificial sand crushing equipment?
What are the crushing methods?
At present, there are many types of crushing machines on the market, but their ways to apply external force can be divided into the following types.
The materials are sandwiched between two working faces and are crushed due to the increasing static pressure applied by the working faces, which destroys the cohesion between the particles inside the rock crystal as well as the cohesion between the rock crystals and the crystal surface.
Squeezing method and crushers adopt it
The materials are crushed by instantaneous impacts generated by:
- the moving working body on the material;
- the high-speed moving material on the fixed working face and suspended material;
- the high-speed moving material impact on each other.
Impact method and crushers adopt it
When the materials are in two relatively moving working faces, they are crushed by the shear force applied by the working surfaces, or by friction between themselves.
Rod mills and wheel mills
Crushers: rod mills, wheel roller, etc.
What are the characteristics of different crushing machines?
The performance of various commonly used crushers is as follows:
|Types||Crushing method||Motion pattern||Crushing ratio||Application||Applicable Materials|
|Jaw crusher||Mainly crushing||Back and forth||4-6||Coarse crushing||Hard and medium hard materials|
|Cone crusher||Mainly crushing||Rotation||
4-6 for coarse crushing
3-17 for middle and fine crushing
|Coarse crushing, middle and fine crushing||Hard and medium hard materials|
|Roller crusher||Mainly crushing||Rotating (slow)||3-8||Middle and fine crushing||Materials below medium hard|
|Impact crusher||Impact||Rotating (fast)||≥10, even 40||Middle crushing||Medium hard and soft materials|
|Hammer crusher||Impact||Rotating (fast)||
Double rotor: 30
|Middle and fine crushing||Medium hard or brittle materials below medium hard|
Before sand making process, coarse crushing and medium crushing are generally adopted.
Jaw crushers are commonly used in coarse crushing.
Generally, cone crusher or impact crusher are used for medium crushing. Cone crusher is aimed at processing high-hardness materials; while impact crusher for brittle and soft materials. The hammer crusher is only suitable for crushing brittle materials with low hardness and low water content.
If necessary, the roller crusher can be used to finely crush coal, limestone, cement clinker, feldspar and other materials with medium hardness and below.
How to choose sand making machine?
HVI and VSI sand making machines
Both types of sand making machines have many models, which is suitable for a variety of customers; they can also be equipped with a mobile crushing station to form a mobile sand making machine.
In addition, the two equipment meets environmental protection requirements, so there is no need to worry about the environment pollution problem....
Their performances are shown below:
|Types||HVI sand making machine||VSI sand making machine|
|Function||Sand making + shaping||Sand making|
|Discharging effect||Better grain shape||/|
|Lubrication method||Thin oil and grease||Thin oil|
|Energy consumption||Low (up and down turnable peripheral guard plate and combined throwing head)||/|
In short, if you need a large yield, cost-effective machine, you can choose VSI sand making machines. If you need advanced structure and perfect finished grain shape, you can choose HVI sand making machine.
Of course, the specific equipment configuration needs to be combined with the specific material and production requirements as well as local conditions.
Technical requirements of vibrating screen
The screening process is the main factor affecting the gradation of artificial sand, among which the shape and size of shaker holes and the inclination angle of the screen surface are the key parameters affecting the quality of artificial sand.
Vibrating screen working on site
- 1 In the production of artificial sand, there is a large content of stone powder particles, and the gradation requirements are high, so it is not suitable to choose rectangular and circular sieve, generally a square sieve is adopted.
- 2 The larger the screen size, the larger the fineness modulus of artificial sand and the lower the stone powder content. On the contrary, the smaller the fineness modulus and the larger the content of stone powder. In the general sand making process, the recommended mesh is 3.5-4.5 mm.
- 3 The inclination angle of the screen surface is generally about 20°.
How to choose artificial sand powder removal equipment?
There will be 10%-20% stone powder (75μm particles) in the production process of artificial sand.
- A proper amount of stone powder can improve the poor workability and increase the compressive and flexural strength of artificial sand concrete.
- But too high content of stone powder will affect its performance, so the artificial sand should be de-dusted.
The equipment and characteristics of the commonly used powder removal process are as follows.
Artificial sand powder removal equipment
Dry powder removal
Equipment: powder concentrator
Dry sand making refers to the use of dry sand making production lines to process artificial sand aggregates. The sand produced from the sand making machine does not need to be cleaned with a sand washing machine, and the sand powder is separated by a powder separator.
- 1 Remove the content of mud powder in the sand to reach the standard of construction sand.
- 2 While removing the mud powder, leave a proper amount of stone powder to enhance the advantages of artificial sand in concrete.
- 3 There is no need to add a lot of water during the production process, which saves water and mineral resources. There is no sewage and sludge discharge, which is more environmentally friendly and the production cost will be relatively low.
- 1 High requirements for raw materials.
- 2 Sand surface sensory poor.
- 3 High cost of equipment.
- 4 Stacking and transportation easily cause environmental pollution and artificial sand segregation.
Wet powder removal
Equipment: sand washing machine
The sand produced by the sand making machine is cleaned the mud powder in the sand is removed to reach the standard of construction sand.
|Spiral sand washing machine||Simple structure, reliable work, convenient operation||Seriously damaged artificial sand gradation, large water consumption, large fineness modulus of artificial|
|Wheel type sand washing machine||High cleaning degree, reasonable structure, large processing capacity, low power consumption, and less ore loss during sand washing||Slightly damaged artificial sand gradation, large water consumption, large fineness modulus of artificial|
Wet powder removel
The powder removal process of artificial sand is the key to control its powder content, which should not only meet the requirements of different grades of concrete, but also should have little influence on the grading.
In areas that lack water resources, powder separators should be used and dry artificial sand and gravel production technology should be adopted.
Areas with abundant water resources are suitable for wet sand production with a spiral sand washer or wheel sand washer. At the same time, fine sand recycling and sewage recycling equipment should be equipped.