HOW TO LAYOUT SAND PLANT
For sand production plant, the process layout directly affects the production effect. While designing the sand plant, there are some principles we should follow. Here are several aspects to be considered in the sand making process layout process, including material properties, finished aggregate fineness and particle shape requirements, site size and production scale, and the expected input and output of the sand making process, etc.
A good production process must fully consider the rationality, reliability, advancement, economy and mutual matching of the process. According to the scale to be processed, the lithology of the rock, and the requirements of the finished aggregate, a better process layout is designed. The process layout is generally considered according to the following principles:
1. Crushing ratio
To measure the crushing effect of a crusher, the concept of crushing ratio is commonly used. The crushing ratio is the ratio of the particle size of the raw material to the particle size of the product after crushing. It represents the multiple of the reduction of raw materials after crushing, and there are many ways to calculate the crushing ratio:
1) Calculate the ratio of the maximum particle size of the raw material before crushing to the maximum particle size of the product after crushing;
2) Calculated with the average particle size.
Since the crushing ratio is the main factor to determine the number of crushing sections, the finer the product particle size is, the more crushing sections there are. However, from the perspective of crushing ratio, the crushing ratio i=3~5 should be selected for coarse crushing, and the crushing ratio i=4~5 for medium crushing, and the crushing ratio i=5~8 for fine crushing should be selected. Only in this way can the performance of equipment at all levels be maximized, so as to obtain a better crushing effect.
If a certain crushing link fails to reach the required crushing ratio, it will inevitably cause pressure and constraints to the next stage of crushing, which will increase the number of system failure points and reduce the reliability of its operation. Therefore, the selection and allocation of crushing ratio is the first principle to pay attention to.
2. Production scale
The larger the scale of the artificial sand processing system, its economy is the first indicator. Since there are many types of equipment to choose from, there are multiple schemes. By comparing these schemes, it is determined to choose the better economical one under the condition that meets the requirements. This can save investment, reduce production costs, and bring considerable economic benefits.
However, when the scale of its processing system is small, the first consideration is that the process should be simple. It can use two-stage crushing instead of three-stage crushing, and try to use as few crushing, screening and conveying units as possible to meet the design requirements.
3. The particle shape and particle size of the product
The particle shape of the product refers to the geometric shape of the particle, and the particle size of the product refers to the size of the particle. Both the product particle shape and the particle size are the main technological indexes to measure the product quality. As aggregate for concrete, it not only has certain requirements for particle size, the particle shape is also required to be cubic.
However, the grain shapes of the products produced by different crushers are different, so the grain shape of the product is related to the performance of the selected crusher, and of course to the properties of the crushed materials. For example, rocks with a layered crystal structure are prone to needle-like particles.
Common rock crushing methods and principles
Working principle: The parent rock is placed on the sharp edge of the crusher, and the purpose of crushing the parent rock is achieved through the concentration of stress.
Commonly used crusher: rock splitter
Working principle: In the high-speed moving working face, the parent rock is crushed by means of suspended impact or instantaneous impact.
Commonly used crusher: hammer crusher, impact crusher, vertical shaft impact crusher
Working principle: The crystal structure and cohesion of the parent rock are destroyed by the working face, so that it will be crushed due to the reduction of cohesion in the process of crystal change.
Commonly used crusher: jaw crusher, cone crusher, roller crusher
Working principle: The rock is crushed by the joint motion of the relative working face and the shear force generated by the friction between the rock and the working face.
Commonly used crusher: rod mill (roller mill), wheel mill
4. Performance of crushing equipment
The type of crusher directly affects the crushing process and product particle size composition. In general:
A crusher with a higher crushing ratio can reduce the number of crushing sections;
The crusher with lamination crushing principle produces less needle-like shaped products;
The products obtained by the rotary crusher that rely on kinetic energy to crush are mostly cubical;
In vertical shaft impact crusher, the grain shape of the "rock on rock" model is better, but the sand making efficiency is not as good as that of "rock on iron".
5. The nature of the raw material
The crystal structure and compressive strength of the material are one of the important factors affecting the crushing process and equipment selection. Materials with high compressive strength are not easy to be crushed, and equipment with large crushing force needs to be selected. At this time, there are less equipment available for selection.
In addition, materials with granular crystal structure are easy to produce cubic products, while materials with layered crystal structure are easy to produce needle-shaped products. At this time, it is necessary to consider the "shaping" step.
In conclusion, it is a complex system engineering design to choose a production process layout of machine-made sand plant with reliable operation, advanced technology and economical rationality. It is not only necessary to consider the feeding particle size, the requirements of the finished aggregate, the lithology of the rock, but also to reasonably match the crushing and screening equipment and auxiliary facilities, and at the same time, an automatic control system must be selected. Reasonable production process and equipment and facilities configuration can make the sand making plantreasonable, efficient and more economical.