Advantages and Disadvantages of Three Sand Making Processes of Mobile Crusher and Sand Making Equipment

I. Production process of mobile crushing machine-made sand equipment

1. Full dry method

The typical dry sand making production process is mainly as follows: the particle size of crushed stone needs to be controlled within the range of 5-40mm, and the crushed stone is provided to the sand making machine as a raw material, and the fine crushed stone with the particle size within the range of 2-5mm and the crushed stone with the particle size greater than 5mm are returned to the sand making machine for reprocessing by making full use of the screening and grading equipment.

In addition, the raw material with the particle size of less than 2.5 mm is subdivided into two grades, namely less than 0.6 mm and 0.6-2.5 mm, the residual stone powder of the fine sand with the particle size of less than 0.6 mm is removed by an air classifier, and then the three materials with the particle size of 2.5-5 mm, 0.6-2.5 mm and less than 0.6 mm are uniformly mixed by a mixing device, This practice can ensure that the quality is consistent with the product specifications required by the artificial sand.

This process technology does not need to add water in the overall processing system of the system, and needs to adopt rain-proof measures in the relevant links of sand making, and needs to install the alloy rubber sweeper at the head of the belt conveyor to promote the recovery of stone powder.

2. semi-dry method

In the production process of this sand making technology, there are mainly three kinds of raw materials entering the silo for sand making: coarse aggregate with particle size in the range of 5-40 mm is screened by grading after crushing, aggregate with particle size in the range of 2.5-40 mm is returned by grading in the sand screening building, and coarse aggregate with particle size in the range of 2.5-40 mm is returned by grading in the sand screening building. The graded finished coarse aggregate is sieved to dewater the dewatered slag with the particle size within the range of 2.5-5mm.

This process can effectively control the mud content of raw materials for sand making. The finished sand can be divided into the following three types: coarse aggregate sand with a particle size of less than 5 mm is screened by classification, finished fine sand with a particle size of less than 2.5 mm is recovered from the sewage after the coarse aggregate is classified, and finished fine sand with a particle size of less than 2.5 mm is recovered from the sewage. Fine sand with grain size less than 2.5mm.

Semi-dry production technology can effectively solve the problems of large mud content and soft lithology, and can be divided into semi-dry production process with dry method as the main method and semi-dry production process with wet method as the main method according to the quality of raw materials. The production of sand and gravel aggregate by semi-dry method can not only improve the quality stability, but also produce no dust pollution, which is very suitable for all kinds of raw materials. However, because the process method needs to treat a large amount of sewage, which is a big defect and deficiency, the sewage treatment will produce a certain amount of treatment cost, which has a high cost.

3. wet method

At present, many hydropower projects in China are using wet production, which requires special purification equipment for effective treatment of sludge and sewage. The wet sand making process mainly shows the following process characteristics: the inspection and screening and the vertical shaft impact crusher form a closed cycle, two screens of 5mm and 3mm are arranged on the surface of the inspection and screening screen, after dehydration and classification, the products of the rod mill and the particles with the particle size of less than 3mm directly enter the finished sand bin, and the particles with the particle size of 3-5mm need to enter the rod mill again. And particles larger than 5 mm need to be crushed again.

II. Measures for improving the quality of mobile sand crushing plant

1. Coarse aggregate coated with powder

The corresponding flushing process is set in the processing system, which can effectively remove the powder on the aggregate, but special equipment is needed to deal with the mud on part of the aggregate.

Clay and soil can be effectively removed to a large extent by using a long spiral classifier to classify and wash stones with a particle size of not more than 5mm. If the material source contains some rocks that are difficult to remove, such as tuff interlayer, it is easy to produce extremely serious powder coating after secondary crushing, resulting in the mud content in the finished material exceeding the limit.

Therefore, no matter what kind of screening form, not only the application of soil disposal equipment, but also the configuration of related washing processes are needed.

2. Grain size distribution

The application of high grade mix sand in construction, on that one hand, can achieve a substantial saving of cement, on the other hand, can promote the effective improvement of concrete strength. If the mixture ratio is unchanged, but the coarse sand will cause the poor cohesiveness of the concrete, which will lead to the easy separation of the concrete.

If the sand is too fine, even if the cohesiveness of concrete is strong, its fluidity will be greatly weakened, so it will increase the amount of cement, resulting in an increase in construction costs, and also have a negative impact on the formation of concrete strength.