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The technical points of the dry sand making process must be known!

04/08/2020

Dry, wet and semi-dry processes are relatively common in machine-made sand production. With the application of tower-type sand making systems, dry production has gradually become a more popular sand making process in the current market. This article mainly analyzes the advantages, process flow, equipment selection and key technical points of dry sand making.

The advantages of dry process sand:

1) Mine selection is not restricted by water resources

Dry sand production is not restricted by water sources and the environment, and can be carried out in places where water resources are scarce, reducing water pollution.

2) Grading is easy to control.

Dry process only removes particles less than 75μm, all particles are evenly graded, and the gradation area line is good; while wet process water washing removes particles below 75μm, 150μm, 300μm, and even 600μm particles are washed away. It is not well controlled and a lot of stone with useful ingredients is wasted.

Technical points of machine-made sand production and processing:

1.Please consider joint production of sand and stone when building a factory

In engineering applications, the amount of crushed stone accounts for more than twice the amount of sand. Establishing a separate mechanism for the sand plant requires a large investment and limited supply. It is not economically economical. On the basis of the crushed stone production and processing system, an increase of one A set of vertical shaft impact crusher (sand making machine) and a set of dust removal device are used to enter the crushed material crushed by the jaw crusher and some stones with different sizes into the sand making machine to separate the particles that do not meet the grading requirements. Stone powder forming mechanism sand.

2. Mine chooses to value wind direction

For mines with thick covering soil layer, more mud in the interlayer, lower strength of parent rock, greater dolomite content, and layered rock into lamellae, construction of the plant on site should be avoided. The selection of mines should consider the influence of wind direction and wind speed. Try to choose near the barren land of the col. As far as possible, the wind speed is relatively small. The reserves of Shishan meet the requirements, the higher the strength, the better, and the strength of the wool stone base material should not be less than 80MPa. To this end, it is necessary to analyze reserves, strength, mining range, etc. through geological drilling.

3. The terrain of the first and second crusher uses stepped terrain, and the site has sufficient storage capacity

Reasonably designed mechanical equipment installation and stone storage site are extremely important. According to the terrain conditions and wind direction, the equipment is arranged in steps along the mountain trend. The initial crushing should be arranged on the uppermost step of the mining direction, the second breaking and screening equipment should be arranged on the next step, and the finished product discharge should be arranged on the lowermost step, so that the production and the raw material do not interfere with each other, environmental protection and economy.

4. Electricity line design fully considers electricity load

The power consumption of quarry production is relatively large, usually the power consumption of a sand-stone cogeneration plant with a production capacity of 180-200t/h is more than 1000kV•A. When designing the transformer capacity, it is necessary to consider the affluence when all the devices are activated at the same time. The best design of the circuit is not less than 50mm2.

5. Soil removal device is indispensable

The ore material l is loaded into the silo by the loader, and enters the jaw crusher through the vibrating feeder. The crushed stones and soil blocks under 100mm are roughly selected by the feeder and do not enter the jaw crusher, and are sorted to the feeder. In the lower silo, the belt conveyor transports it to the vibrating screen installed on the chute for sieving. The stone below 20mm is basically soil, and the sieve is divided into waste. The crushed stone above 20mm and the stone after the initial break directly enter the transition silo , Effectively prevent the mixing of soil and impurities. In this way, the mud and soil in the wool can be removed, and the mud content of crushed stone and machine-made sand is basically well controlled

6. Selection of sand and stone materials

After processing several kinds of stone material from crushed stone, it is a crucial step to choose which grade of stone material to enter the sand making machine to produce qualified machine-made sand and increase the output. After the impact crusher, the stone material breaks the second crushed stone chips, accounting for about 30% of the total production, and the stone materials below 0.075mm account for about 25% of the stone chips. If the stone chips enter the sand making machine again, there will be more stone powder below 0.075mm and more waste will be produced. The production mechanism sand is not cost-effective. Selecting the impact crusher to break the secondary crushed recycled material into the mechanism sand can produce a high-quality mechanism sand.

7. Quality assurance measures for machine-made sand

1) When the stone material enters the feeding port, a bar feeder is used to remove soil, in order to prevent the produced mechanism sand from exceeding the mud content, and solve the mud content problem from the source.

2) The stacking site is hardened to prevent mud from mixing into machine-made sand during loading.

3) Spray water mist on the top of the machine-made sand belt conveyor to make the small-grain powder in the machine-made sand with the content of stone powder meeting the requirements adhere to the large particles to prevent the separation of stones with different particle sizes when falling, or The method of reducing the pile height by adopting a string barrel reduces segregation.

4) The crushed stone used in the production of machine-made sand adopts the impact crusher to return the cage stone material to avoid the situation of low crushing index of the machine-made sand and to control its mud content.

5) The dry air method is used to measure the air supply of the fan, and the air volume is fixed after the commissioning and normal operation, so that the content of the produced sand powder is controlled in a relatively stable state.

The production and process of sand making by machine-made sand dry method is simple and practical, which reduces the pollution of water resources and is conducive to protecting the environment.

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