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How to deal with excessive mud content in sand and gravel aggregate?

Release time:Apr.17.2024 Views:0

The mud content has a decisive influence on the performance of ready-mixed concrete.(stone crusher) It will significantly accelerate the slump loss of concrete, increase the pumping pressure, increase the risk of cracking, etc. Therefore, the mud content of sand and gravel aggregate is one of the concrete quality standards. An important indicator, in engineering construction, the mud content in concrete raw materials is usually regarded as a hazardous substance that affects the performance of concrete.


In fact, mud content control runs through the entire process of ore mining and production. This technical indicator involves many influencing factors. However, by taking a series of specific measures and strengthening the management of each link, the mud content of sand and gravel aggregates can be effectively controlled. , so that it can adapt to the quality requirements of concrete for sand and gravel aggregates. The following are some countermeasures that can be taken in each link to deal with high mud content:


1. Design link


In order to achieve a good mud removal effect, the process design of the production line should adopt "double desliming", that is, small particles are screened out before the first crushing, the screen size is controlled at 20-40mm, and the mud and ore are removed by vibration. Separate and screen it out through the screen (the size is too small and the mud removal effect is not good, and the size is too large will sift a large amount of stone, which is not conducive to cost control), and the material is screened again after being crushed. You can choose 4 according to the size of the material. -5mm size screen. In addition, during the construction of the source material yard, the boundaries between weakly weathered and strongly weathered materials should be strictly distinguished, and strongly weathered materials should be treated as waste.


2. Mining process


For some ores with mud cracks, if they have a high mud content and contain a lot of fine powder, these ores can be screened out; in addition, when thick mud cracks appear in the ore, you should try to stay away from the mud cracks when placing explosives. To prevent the mud splashed during blasting from contaminating the stone.


3. Production link

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750 bucket sand washing machine.png


The production line is equipped with a sand washing machine. The sand washing machine has the functions of cleaning, dehydration and grading. Under the action of the strong water flow of the sand washing machine, it can effectively complete the washing and dehydration process of sand and gravel aggregates, clean and filter the impurities in the sand, and reduce The mud content of the sand can also be controlled by controlling the number of washing screens to control the grade of the finished sand, thereby greatly improving the quality of the sand and making it meet the standards for concrete use.


In addition, drainage pipes can also be added to the original drainage pipes to increase the drainage volume and flushing intensity. In this way, the flushing area of the sand and gravel aggregates is larger, which can effectively reduce the mud content. According to experimental results, adding a drainage pipe After that, the drainage volume doubled, and the mud content dropped from the original 1.5% to 1% to 1% to 0.2%, which can effectively reduce the mud content of the aggregate.


4. Screening process


The vibration frequency of the vibrating screen can be reduced by reducing the number of eccentric blocks on both sides of the vibrating screen, thereby reducing the mud content of the aggregate. According to relevant experiments, if 4 eccentric blocks are reduced, the residence time of the construction aggregate on the screen increases from 30s to 120s, and the mud content of the aggregate is also reduced from the original 5.3% to 3.8%. The mud content is obtained improved.


You can also reduce the mud content of the aggregate by adding a slow material sill, drilling holes in the diagonal steel of the vibrating screen, and fixing it with bolts on the screen to reduce the sliding speed of the aggregate. Increasing the slow material sill can increase the residence time of aggregates on the screen. According to relevant experiments, after adding the slow material sill, the residence time increased from the original 90s to 150s, and the mud content also decreased from the original 4.3% to 1.5%. The mud content has been significantly reduced.


5. Daily stacking


Regularly check the mud content of coarse and fine aggregates, and stack them according to the difference in mud content. The ground of the stockyard should be flat, with appropriate slopes and drainage facilities to prevent muddy water outside the workshop from entering the stockyard and avoid secondary pollution. . In addition, the storage time of finished products should not be too long and should be used as soon as possible, and irrelevant equipment and personnel should be prohibited from entering the finished product yard.

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750 dehydration screen

750 fine sand recovery machine


The above are several common ways to solve the problem of excessive mud content in concrete. In addition, the mud content can also be reduced through fine sand recovery machines and dewatering screens.


The new high-resistant heavy-duty fine sand recovery machine can separate the mud and sand in the sand-water mixture, and extract and collect the fine sand. Through cleaning, dehydration, and classification, the quality and output of the sand are improved, and the mud content of the sand is greatly reduced. The fine sand recovery rate is as high as More than 85%; the main function of Xingao heavy-duty high-efficiency high-frequency dewatering screen is dehydration, desliming and demediation. It is often used in wet sand making production lines and sand washing machines. It has a lower investment cost than sand washing machines, so it is used in some applications. Materials with low mud content, such as quartz sand, can also be used alone, which can reduce investment costs.