30 questions about artificial sand and sand making process

With the popularity of artificial sand, more and more customers are consulting artificial sand and sand making equipment. Here are 30 common questions about artificial sand and sand making process.

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1. what are the main advantages of dry sand production line?

The main advantages of dry sand production line are:

1) The produced sand has a low moisture content, generally less than 2%, and can be directly used in commercial concrete and dry-mix mortar;

2) The content of stone powder in the finished sand is adjustable and controllable, centralized recycling can be used comprehensively, and dust emission can be reduced;

3) Little or no water is used in the production process to save water resources and protect the environment;

4) Easy to centralize operation control and realize automatic management;

5) It is not affected by drought and cold seasons, and can be produced continuously throughout the year.

2. why is the wet sand production process less and less used?

The main reasons are:

1) Consume a lot of water, it needs 2~3.5m³ of water to produce 1t artificial sand;

2) The produced sand has high water content, which must be dehydrated, and need to be re-dried when used in dry-mixed mortar;

3) The fineness modulus of product sand is relatively coarse, and the sand output is low;

4) Produce a lot of mud powder sewage, pollute the environment, and the stone powder is not easy to recycle;

5) There are many types of infrastructure investment and equipment, and the production cost is high;

6) It cannot produce normally in arid and drier areas or in freezing seasons.

3. what are the features of semi-dry sand making process?

Compared with wet sand making process, the most important feature of semi-dry sand making process is that mud and stone powder on the surface of the sand-making raw materials is washed off with water. Part or all of the finished sand is no longer washed with water, so the water consumption is relatively small, and the loss of stone powder in the finished sand is less, making the moisture content is low.

4. what is the methylene blue (MB) value of artificial sand?

The methylene blue (MB) value is used to determine whether the content of particles with a particle size of less than 0.075mm in the artificial sand is mainly mud or stone powder with the same chemical composition as the processed parent rock. The methylene blue value of machine-made sand requires MB&#;1.4, and it should be controlled below 1.0.

5. why do we need to humidify and mix the finished sand?

In the artificial sand dry production process, the humidify and mix of the finished sand can make the moisture content reach the saturated surface dry state, which is beneficial to the control the water consumption of subsequent concrete mixing, and can reduce segregation and dust during transportation.

6. why is the fineness modulus of artificial sand unstable?

In the production process, the lithology, moisture content and gradation of the feed material are easy to change, and the screening process will also cause problems such as blockage and damage and the efficiency and parameters of the crushing and dust removal equipment are also unstable, which may easily lead to the unstable of the fineness modulus of the artificial sand.

7. Can waste concrete and brick be used to produce artificial sand?

Waste concrete, masonry and industrial waste are sorted, washed, crushed, and screened through special equipment to produce artificial sand. However, they are mainly used to produce recycled coarse aggregate currently.

8. what are the bases for choosing artificial sand production process?

1) First of all, it depends on the area where the production line is located, the water resources, the cleanliness of the raw materials, and the specific requirements for aggregate, machine-made sand and gravel powder content, and fineness modulus. If the original conditions permit, dry production process is preferred, and then semi-dry production process, wet production process is the last.

2) Considering the equipment investment, the size of the floor area, the difficulty of production management, and the cost of artificial sand and gravel processing, dry production process is also preferred, and then semi-dry production process, wet production process is the last.

9. how to take samples of artificial sand?

The general method for testing and sampling of artificial sand is:

1) When sampling on the pile, the sampling sites should be evenly distributed. Before sampling, remove the surface of the sampling site, and then extract 8 pieces of roughly equal amount of sand from different parts to form a group of samples.

2) When sampling from the belt conveyor, a catcher is used to regularly sample 4 equal parts of sand at the outlet of the end side of the belt conveyor to form a set of samples.

3) When sampling from trains, cars, and cargo ships, 8 parts of roughly equal amounts of sand are taken from different parts and depths to form a set of samples.

10. how to detect the powder content in artificial sand?

There are two methods to test the powder content in artificial sand: washing method and dry sieving method. The representative is ASTMC136 or AASHTOT27, which is suitable for dry sieve and ASTMC117 or AASHTOT11, which is suitable for water sieve.

11. what are the main process methods for stone powder separation?

The current methods for removing excess stone powder in undisturbed sand mainly include water washing hydraulic classification, high-frequency sieve mechanical sieving method, and powder-selecting dust-removing wind classification method.

12. how to adjust the gradation index of artificial sand particles?

The gradation of artificial sand particles can be achieved by adjusting the feed gradation, feed volume, crusher speed, screen size and other aspects.

13. what are the factors affect the artificial sand grain shape?

The factors that affect the artificial sand grain shape are:

1) The lithology of the source rock, such as the development of joints is not conducive to obtaining a better grain shape;

2) Type of crushing equipment, impact crusher has better final products shape;

3) Screen type, such as square holes, has better control of the grain shape.

14. why do we need to "replace grinding with crushing, more crushing& less grinding&#;?

Because the energy utilization rate of crushing is higher than that of grinding, more crushing and less grinding are beneficial to save energy, but it cannot be completely replaced by crushing.

15. what are the features of &#;rock on rock&#; and &#;rock on iron&#; crushing methods of vertical shaft impact crusher?

The &#;rock on rock&#; crushing method is suitable for crushing abrasive materials with medium hardness and above, such as basalt etc. The shape of the finished products is good under the crushing method of "rock on rock".

The &#;rock on iron&#; crushing method is suitable for crushing abrasive materials with medium hardness and below, such as limestone etc. Under the &#;rock on iron&#; crushing method, sand making machine has high efficiency.

Besides, &#;rock on rock&#; crushing method is used for shaping and &#;rock on iron&#; crushing method is used for sand making.

16. why does the vertical shaft impact crusher (sand making machine) adopt dual motors?

The dual motors in sand making machine has two main functions:

1) The dual motors ensure the balanced force of the spindle.

2) Ensure the speed. Energy will be lost during the transmission process; the dual motors ensure high power and ensure the speed.

17. how to solve the large deviation of the working current between the dual motors?

In dual-drive equipment, the phenomenon that the current of one motor is lower than the other is called inert response, and the deviation requirement should not be greater than 10%; and we can solve this problem by adjusting and equalizing the tension of the transmission belt, checking the cleanliness of the terminal and checking the soft start.

18. why should the impeller rotor be corrected for static balance?

If the impeller rotor does not perform proper static balance correction, the rotor has large imbalance, and the centrifugal force generated during operation will cause abnormal vibration and failure of the equipment, abnormal wear of the rotor, and excessive noise. According to industry standards, the impeller rotor balance level of the vertical shaft impact crusher is G16.

19. what are the basic steps to correct the static balance of impeller rotor?

After replacing the wear parts of the impeller rotor of the vertical shaft impact crusher, the basic steps to correct the static balance are:

1) Clean the sand and gravel, old worn parts, debris, etc. on the rotor and accessories, and confirm that they can continue to be used;

2) Reinstall the wear parts and install the rotor on the balance tooling;

3) Confirm the unbalanced weight and position;

4) Recheck the balance of the rotor.

20. what are the factors that affect the efficiency of vertical shaft impact crusher?

1) The properties of raw materials. If the raw material has low hardness and strength, good crushability, the efficiency of sand making is high;

2) The moisture content of raw material. If the moisture content of raw material is high, it will reduce the sand production capacity;

3) The feeding volume. Generally speaking, the larger the feeding volume, the better the crushing effect. But, there is an extreme point;

4) The speed of the impeller. The higher the speed, the better the crushing efficiency.

21. why does the vertical shaft impact crusher vibrate strongly at start?

It is because the rotor does not form a uniform lining at the beginning of the operation and leads to the vibration. It is generally necessary to feed in a few squares of fine material at the beginning. If the coarse material is fed in to the machine at the beginning, it will continue to vibrate for several hours until a uniform material lining is formed in the rotor.

22. what type of vibrating screen is used for sand making currently?

The screening equipment mainly used for sand and gravel production is: bar screen, cylindrical screen, circular vibrating screen, linear vibrating screen, high frequency screens and probability screen. Among them, bar screens are mainly used for soil removal process. Circular vibrating screen and linear vibrating screen are more commonly used.

23. what factors can cause screen blocking?

1) The sand and gravel contains a large number of particles with critical separation points;

2) The sand and gravel contains more flake materials and cannot be screened smoothly;

3) The sand and gravel has high mud content;

4) The sand and gravel has high moisture content.

24. why is the screen mesh easily damaged?

1) The quality or material of the screen mesh is unqualified;

2) The tension of the screen mesh is not enough, which causes the screen to vibrate, and the broken or damage is generally along the edge of the screen mesh or at the edge layer;

3) The vibration amplitude of the vibrating screen is too small, making the sand particles accumulated on the screen mesh and quickly damages the screen mesh.

25. what is the relationship between the fineness modulus and the screen size?

At present, the general requirement for the fineness modulus of artificial sand is 2.6-3.0, and it is generally recommended to use a screen size of 3.0mm or 3.5mm.

26. what are the wear-resistant parts of vertical shaft impact crusher?

Standard wear-resistant parts include: cylindrical roller bearings, deep groove ball bearings, thrust ball bearings, expansion sleeves, conveyor belts, oil seals, and O-rings.

Goto Chunlei to know more.

Non-standard wear-resistant parts include: upper bushing, lower bushing (lifting part of the feeding hopper), shock-absorbing rubber, flap guard ring, upper/lower runner plate, impact block, split cone, wear plate, throwing material head, blanking lining ring, feed pipe, upper/lower striking guard plate, hopper lining ring, distribution tray, bulk tray (bulk cone), peripheral guard plate.

27. why wheel sand washing machine is generally used in wet sand production line?

Wheel sand washing machine has simple structure, and its failure rate is much lower than that of spiral sand washing machine. And in the washing process, the loss of fine sand and stone powder is less, the gradation of final produced sand is well and the fineness modulus is easy to control and the quality of finished sand is stable.

28. what are the requirements about the apparent density and loose bulk density of artificial sand?

The apparent density of artificial sand is not less than kg/m³; the loose bulk density is not less than kg/m³; the porosity is not more than 44%.

29. what are the types of rocks in nature?

Natural rocks are divided into three types:

The first type is magmatic rock (igneous rock), which is formed by magma eruption, and is generally hard and uniform;

The second type is sedimentary rock (sedimentary rock), which is weathered, transported, deposited and formed by a series of geological processes such as diagenesis. Generally, it has layered distribution structure with similar properties in the same period;

The third type is metamorphic rocks, which are formed after metamorphic mixing on the basis of existing rocks. It has both the above-mentioned rocks&#; features and its own features.

The characteristics have both the above-mentioned rock and its own characteristics.

30. which rocks can be used for artificial sand production?

Granite, basalt, pebble, andesite, rhyolite, diabase, diorite, sandstone, limestone and other varieties are usually used for artificial sand production. According to the different types of the rocks, the strengths and applications of the artificial sand are also different.

In sand production line, especially in wet sand production line, sand washing is an essential part in order to improve the quality of finished sand, and sand washing machine is needed for sand washing.

The sand washing machine can wash away the soil and impurities on the surface of the sand, and at the same time destroy the water vapor layer covering the sand, so as to facilitate dehydration, play the role of efficient sand washing and cleaning, and improve the quality of the finished sand.

There are different types of sand washing machines, all of which have their own characteristics and scope of application. So how to choose a suitable sand washing machine? This article will introduce you from several aspects.

Types of sand washing machine

The common types of sand washing machines on the market include spiral sand washing machines and impeller sand washing machines.

Spiral sand washing machine

The spiral sand washing machine mainly stirs the sand and gravel through the spiral device in the equipment, so that the sand and gravel are mixed with water. Then the sand and gravel are gradually screened under the action of the spiral, and discharged from the discharge port, thus realizing the cleaning and screening effect of the sand and gravel. In terms of type, it can be divided into two types: single-spiral sand washer and double-spiral sand washer.

It is mainly suitable for washing, grading and impurity removal in metallurgy, building materials, hydropower and other industries, especially suitable for construction sand and road construction sand.

Impeller sand washing machine

Impeller sand washer is claso called wheel bucket sand washing machine. The sand and gravel in the wheel bucket sand washing machine are turned over under the drive of the wheel bucket, and grind each other to remove impurities on the surface. At the same time, add water to the inside of the sand washing machine to form a strong water flow, and take away the washed out impurities and other foreign objects with small specific gravity in time. The clean sand and gravel are taken away by the blades and poured into the discharge tank trough from the rotating impeller, thus completing the cleaning of the sand and gravel. It mainly includes single-row wheel bucket, double-row wheel bucket and three-row wheel bucket sand washing machine.

It often forms a high-quality sand production line together with a sand making machine, which is used in transportation, chemical industry, mining, water conservancy and hydropower and other fields.

Difference between spiral sand washer and impeller sand washer

Appearance structure

The overall structure of the wheel bucket sand washing machine is relatively simple. There are fewer wearing parts in the equipment, and after the installation is completed, its occupied area is small. In order to reduce the phenomenon of bearing damage caused by water, sand and pollutants, the wheel type sand washing machine has designed a structure in which the impeller drive bearing device is isolated from water and sand, thereby greatly reducing the failure rate of the equipment.

The spiral sand washer has a slender body and a horizontal structure, which makes the structure simpler. But it is not as convenient as the wheel sand washer in the installation arrangement.

Applicable material particle size

The wheel bucket sand washer is generally used to clean materials of about 5mm. And the spiral sand washing machine can not only clean the large size of the stone, but also the smaller size of the material.

The loss of sand and gravel

The wheel bucket sand washing machine consumes less water during the sand washing process, and the loss of fine sand and stone powder is small, so that the sand grade and fineness modulus of the washed sand and gravel can meet the standard requirements.

In comparison, the sand and gravel loss of the spiral sand washing machine is relatively large during the sand washing process.

Cleanliness of the washed sand

The cleanliness of sand washing refers to the quality of finished sand after washing.

During the cleaning process, the sand and gravel in the spiral sand washing machine are turned over and cleaned more times, and the cleaning is more thorough, so the quality of the finished sand and gravel is better.

Cleaning capacity

The cleaning capacity of the spiral sand washing machine is relatively strong, and it can effectively clean the sand with serious mud impurities. It is often used in large-scale sand production lines.

The production capacity of the wheel sand washer is smaller than that of the spiral sand washer, so it is more suitable for small and medium-sized sand production lines.

Water consumption

The wheel bucket sand washing machine does not need to use too much water during the sand washing process, and the loss of fine sand is small.

However, the water consumption of the spiral sand washing machine is relatively large, and the sand and gravel are lost more.

Price

The price of the wheel bucket sand washer is relatively low, and the operating cost is also low, which belongs to the type of economical and efficient sand washer. The price of the spiral sand washer is relatively high, which belongs to the high-end sand washing machine.

If your project requires a small output, you can choose a wheel bucket sand washer. However, the transportation cost of the large-capacity wheel sand washer is relatively high, so if your project requires a large-capacity machine, you can choose a spiral sand washer.

How to choose a right sand washing machine?

Choosing the right sand washing machine requires comprehensive consideration of the following aspects.

First of all, it is necessary to consider which sand washing machine to choose. If you compare the sand washing effect between the spiral sand washer and the impeller sand washer, it should be considered in combination with the actual production situation.

The spiral sand washing machine has high efficiency, large processing capacity, and relatively clean sand washing, but it consumes a lot of water and loses more fine sand. The output of the impeller sand washing machine is relatively low, but the water consumption is small, the loss of fine sand is less, and the price is cheaper than the spiral sand washing machine.

Therefore, if the sand and gravel to be cleaned have a large particle size, a spiral sand washing machine can be selected. If the budget cost is low or the project scale is relatively small, you can choose the impeller sand washing machine.

Second, look for a trustworthy manufacturer. Whether online or offline, you can find many manufacturers of sand washing machines. You can learn more about manufacturers through their websites, social media accounts, etc. You can also visit their factories and offices offline to learn about the production process of the equipment. In this way, comprehensively evaluate the strength of the manufacturer to ensure that you can buy a high-quality sand washing machine.

The price of the equipment is also a very important factor. You can get quotes from different manufacturers online to choose the most economical one. However, when buying a sand washing machine, you can't just pay attention to the price and choose the manufacturer with the lowest quotation. That's because the lowest price can mean a lower-quality product. This will cause you to invest more in maintenance costs during use.

Then, you also need to find out from the manufacturer what kind of after-sales service they can provide. If the equipment needs to replace wearing parts, can they be sent to the construction site in time? If the sand washing machine breaks down, can their engineers come to repair it? Good after-sales service can ensure the normal operation of your equipment and shorten the downtime caused by failure.

Finally, find out what your customers are saying. If most customers are satisfied with a manufacturer's equipment and their services, it means that the manufacturer is trustworthy. If half or more of the customers who have a bad opinion of the manufacturer, you'd better not choose to cooperate with such a manufacturer, otherwise it may cause you certain economic losses.

How to configure the sand washing production line?

Sand and gravel materials mainly include two types, natural sand and artificial sand. Different types of sand require different sand washing production lines.

If your raw material is natural sand, such as river sand, sea sand, etc., your production line configuration should be like this (the following production line is for reference only, when actually configuring the sand washing production line, you need to comprehensively consider various factors).

If you want to produce artificial sand, sand washing machine is not enough, you also need a series of sand making equipment. There are many types of raw materials that can be used to produce machine-made sand, such as river pebbles, limestone, granite, basalt, etc. According to the different raw materials, the configuration of the sand making production line is also different. The line configurations provided below are for reference only.

If the sand is fine, a fine sand recovery machine can be added, otherwise the sand that is too fine will be washed away during the sand washing process. This will not only cause serious loss of finished products, but also affect the gradation of sand, resulting in unreasonable gradation and large fineness modulus, which greatly reduces the quality of machine-made sand. Excessive discharge of fine sand will also cause environmental pollution.

So in this case, you need to add a fine sand recycling machine after the sand washing machine to recover the fine sand lost from the sand washer. This can not only reduce loss, but also realize the effective utilization of sand and gravel resources.

If you need to configure a sand washing production line, please feel free to consult us. We have professional engineers to customize the suitable sand washing production line for you!

30 questions about artificial sand and sand making process

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