Investment Guidelines for Manufactured Sand

In the past two years, with the continuous increase in environmental protection measures, traditional extensive sand and gravel enterprises have successively shut down and reorganized, facing transformation and upgrading, and natural sand and gravel production capacity has also sharply decreased. As an important building material and concrete raw material, sand and gravel are widely used in the construction of houses and road engineering floors, with a huge market demand. Replacing natural sand with manufactured sand has become an inevitable trend in industry development, and the sand and gravel industry is also striving towards standardization and environmental protection.

What is manufactured sand?

Manufactured sand refers to rock, mine tailings, or industrial waste particles with a particle size of less than 4.75mm, which are made by mechanical crushing and screening after soil removal treatment, but do not include soft or weathered particles, commonly known as machine-made sand.

There are many raw materials that can be used for manufactured sand production, such as granite, basalt, river pebble, cobble, limestone, calcite, andesite, rhyolite, diorite, diabase, sandstone, quartzite, etc.

In addition, in the context of a high pursuit of environmental protection, the call for the mining and gravel aggregate industry to "turn waste into treasure" is becoming increasingly high. In addition to conventional materials for manufactured sand production, tailings, slag, and construction waste for sand production have gradually come into people's sight.

Development prospect of manufactured sand

At present, natural sand is limited and the cost is increasing, unable to meet the increasing market demand, high-quality, affordable, and environmentally friendly manufactured made sand is highly anticipated.

Manufactured sand not only comes from a wide range of sources, easy to operate and control, good performance, can meet the needs of construction, but also economically feasible and beneficial to the protection of the natural environment. With the further adjustment and optimization of all kinds of enterprises' layout and construction of machine-made sand business and industrial structure, it has become the basic consensus of upstream and downstream enterprises to reduce the use of natural sand in the future. Manufactured sand may become the mainstream of the construction sand market and the development direction of the construction market in the future.

Production process of manufactured sand

Dry method production process

In areas with cold weather, drought, low rainfall, and lack of water resources, we prefer to use dry method production process.

After the raw materials are screened by vibrating feeder and vibrating screen, they are crushed by coarse crushing and medium crushing equipment, and then screened by check screening equipment. The screened materials are divided into 3 parts:

1. The coarse crushed particles that cannot meet the product particle size requirements are returned to the medium crushing equipment for re-crushing, and this part of the returned material forms a closed circuit between medium& fine crushing and screening;
2. Medium sized particles are directly conveyed to product warehouses or storage yards as finished aggregate;
3. Raw materials smaller than a certain size are fed into vertical shaft impact crusher for shaping and sand making. The stone powder generated in the sand making process is collected by powder selection machine and air dust removal equipment, and enters a closed stone powder warehouse.

Advantages of dry method production process:

1. The moisture content of finished aggregates and manufactured sand is low, generally not higher than 2%. It will not freeze when the temperature is below zero in winter, and can be continuously produced throughout the year.
2. The content of stone powder in the finished sand can be controlled, which has a higher sand production rate compared to wet method, and the concrete produced from this finished aggregate has a relatively high strength.
3. Fine stone powder, the byproduct, can be used as raw material for roadbed cushion or cement unburned bricks, with high resource utilization rate and basically achieving zero emissions.
4. There is no need for water treatment, the system is relatively simple, so the investment is small, the land occupation is small, the operation and management personnel are few, the production capacity is large, and the production cost is also low.
5. The process flow is short and the equipment is simple and easy to centrally control, which can easily achieve automated or unmanned production operation.

Disadvantages of dry method production process:

1. The content of impurities such as soil should be strictly controlled; otherwise it is easy to cause blockage and overload of the dust collection system.
2. There is a certain amount of stone powder residue on the surface of the produced aggregate, with low cleanliness and slightly poor appearance.
3. Dust will be generated during the stages of stone crushing, screening, sand making, and transportation. So, the requirements on equipment sealing and dust removal are strict.

Wet method production process

The wet method sand production process is generally adopted in areas with abundant water resources.

Advantages of wet production process:

1. The produced sand and aggregates have clean surfaces, good visual properties, and good quality.
2. Using a large amount of water for washing, no dust pollution.

Disadvantages of wet production process:

The production process requires a large amount of water, typically requiring 2-3.5m3 of water to produce 1 ton of sand and gravel.

The produced manufactured sand has a high moisture content, content of particles less than 0.16mm is low (usually 10%), coarser fineness modulus, and lower sand production capacity.

During the production process, a large amount of sludge wastewater is discharged, polluting the environment; the cost of recycling is high and the effect is poor.

The production line requires many types of equipment, and the land occupation is large, the investment is high and the production cost is also high.

Adequate water resources are required; the production is affected in dry and rainy areas or during cold and freezing seasons.

With more than 30 years’ experience in the sand aggregate industry, ZENITH can provide customers with customized dry and wet production processes. Starting from cost reduction and efficiency improvement, ZENITH's production process highly combines factors such as geographical characteristics, environment, parent rock, finished product, cost, and profit to fully realize project value and benefits.

How to Choose the Manufactured Sand Crusher?

The equipment selection for sand and gravel aggregate production system is generally based on the characteristics of raw materials, production scale, site layout conditions, production process, etc. The main equipment involved includes crushers, vibrating screens, sand making machines, and auxiliary equipment includes belt conveyors, feeders, stone powder recovery equipment, and dust collectors.

According to the properties of the raw material (especially particle size and hardness) and the different requirements for the particle size of the crushed product, the crushing process is mostly multi-stage crushing. In the coarse crushing stage, gyratory crusher and jaw crusher are commonly used; in the medium and fine crushing stage, impact crusher and cone crusher are commonly used; in the sand making stage, vertical shaft impact crusher is generally used.

Gyratory crusher

The gyratory crusher is a coarse crusher suitable for crushing flake materials and it is suitable for use in factories and quarries with large production capacities. The feed particle size can reach 450-1000mm, and the average discharge particle size is ≤5-8mm.

The gyratory crusher adjusts the discharge port in two ways:

One is to use mechanical means, with an adjusting nut at the upper end of the main shaft. By rotating the adjusting nut, the crushing cone can be lowered or raised, causing the discharge port to become larger or smaller accordingly;

The second method is to use hydraulic adjustment, with the main shaft located on the plunger inside the hydraulic cylinder. By changing the volume of hydraulic oil under the plunger, the upper and lower positions of the crushing cone can be changed, thereby changing the size of the discharge port.

Advantages:

1. The crushing process is carried out continuously along the circular crushing chamber, resulting in high productivity, low power consumption, and stable operation.
2. The raw materials can be directly poured into the feeding port from the transportation tool, without a feeder, which is convenient to operate and easy to maintain.
3. The structure is simple and reasonable, and the operating cost is low. Utilizing the principle of “rock on rock’, the wear is minimal.
4. The products are cubical and have high bulk density, small iron pollution.

Jaw crusher

The jaw crusher consists of two jaw plates, a movable jaw and a fixed jaw, forming the crushing chamber. It simulates the movement of the two jaws of an animal and completes the material crushing operation. The maximum compressive strength of the crushed material is 320Mpa.

Advantages：

1. Low noise and less dust; single machine energy saving is 15% to 30%, and system energy saving is more than double.
2. Large crushing ratio, uniform product particle size; the adjustment range of the discharge port is large, which can meet the requirements of different users; the crushing chamber is deep and has no dead zone, improving the feeding capacity and output.
3. Simple structure, reliable operation and low operating cost.
4. The lubrication system is safe and reliable, with convenient component replacement and simple equipment maintenance.

Impact crusher

Advantages:

1. When the moisture content of the material is too high, the feeding chute and impact plate of the impact crusher can be equipped with heating devices to prevent material adhesion. There is no sieve plate at the bottom, which can effectively prevent blockage.
2. The rotor of the impact crusher has greater momentum and lower energy consumption.
3. The impact crusher can adjust the discharge particle size through various methods, such as adjusting the rotor speed, adjusting the gap between the impact plate and the crushing chamber, etc.
4. Low wear of wear-resistant parts and high metal utilization rate; easy replacement of spare parts and corresponding reduction in maintenance costs.

Cone crusher

Cone crusher has large crushing ratio, high efficiency, low energy consumption, and uniform product particle size, suitable for medium and fine crushing of various ores and rocks.

Advantages: (take HPT series multi cylinder hydraulic cone crusher as an example)

1. Combines higher speed and stroke, the rated power and throughput capacity are greatly improved, improving the crushing ratio and production efficiency.
2. Reasonable structure, advanced crushing principle and technical parameters, reliable operation, and low operating cost; all components of the crusher are equipped with wear-resistant protection, reducing maintenance costs to the minimum and increasing the general service life by more than 30%.
3. The selective crushing of materials significantly increases the proportion of fine materials and cubical particles content in the product, greatly reducing needle like materials.
4. The unique design of the thin oil lubrication system greatly improves the service life of the equipment.
5. All parts can be disassembled and maintained from the top or side, and the disassembly and assembly of the moving cone and fixed cone are convenient. There is no need to disassemble the frame or tighten bolts, making daily replacement of the lining plate of the cone crusher more convenient.
6. Higher production capacity, better product particle size, and easy automatic control, with maximum reliability and flexibility, truly creating more value for users.

Sand making machine (vertical shaft impact crusher)

Vertical shaft impact crusher is widely used for medium and fine crushing (sand making) of various hard and brittle materials such as rocks, abrasives, refractory materials, clinker, quartz, iron ore, concrete aggregate, etc. It is particularly suitable for building sand and road construction sand and gravel production.

Advantages:

1. Lightweight and compact in structure.
2. High crushing efficiency, with fine crushing and coarse grinding functions; the product has high bulk density and minimal iron pollution.
3. The product has excellent particle shape, is cubic in shape, and has a very low content of needle like particles. It is suitable for aggregate shaping, manufactured sand making, and high-grade highway aggregate production.
4. Simple structure, convenient installation and maintenance, and low operating cost; low energy consumption, high yield, and high crushing ratio.

Circular vibrating screen

The circular vibrating screen adopts cylindrical eccentric shaft exciter and partial block to adjust the amplitude. It has long screening line and multiple screening specifications, and is characterized by reliable structure, strong excitation force, high screening efficiency, low vibration noise, durability, convenient maintenance, and safety operation.

According to the raw material and user requirements, high manganese steel woven screen mesh, perforated screen plate, and rubber screen plate can be used. There are two types of screen plates: single layer and double layer, and each type of screen plate can meet different requirements for screening effect.

Belt conveyor

According to the requirements of the conveying process, it can be transported by a single unit, or composed of multiple units or combined with other conveying equipment to form a horizontal or inclined conveying system to meet the needs of different layout forms of production lines.

Belt conveyor has strong conveying capacity, long conveying distance, simple structure and easy maintenance, and can easily achieve programmed control and automated operation.

Feeding equipment

The vibrating feeder in sand and gravel production lines is used to evenly or quantitatively supply materials from storage bins or other storage equipment to the receiving equipment, and is essential equipment for implementing flow operation automation. There are three main types:

1) Electromagnetic vibrating feeder

The electromagnetic vibrating feeder can transport various loose granular and powdered materials, as well as large materials with a particle size of up to 500mm. For powdered materials, sealed feeding can be used.

2) Grizzly feeder

The grizzly feeder is used for uniform feeding of large pieces of material before the coarse crushing. At the same time, due to the effect of the rod screening surface, it can remove fine materials such as soil, achieve pre-screening function, and improve the coarse crushing capacity.

3) Screw feeder

Screw feeder is a new product that integrates stable flow conveying, weighing and quantitative control of powder materials; it is suitable for the continuous measurement and batching of powder materials in various industries.

It adopts multiple advanced technologies, and has reliable operation and high control accuracy; especially suitable for continuous measurement and batching of powder materials in industries such as building materials, metallurgy, power, and chemical engineering.

The products of ZENITH cover various types of coarse crushing, medium crushing, fine crushing, sand making, washing, feeding, screening, conveying equipment, and mobile crushing and screening equipment required for the sand and gravel aggregate industry.

How to choose sand process equipment manufacturer?

The comprehensive strength is mainly reflected in the production scale of the manufacturer, whether they have their own professional research and development and quality inspection teams, and whether the manufacturer has strong funds.

In general, equipment from large brands not only has guaranteed quality, large market share, low failure rate, durability, but also maintains value. High quality equipment is more stable and reliable in actual operation, with high operating rate, high production efficiency, low failure rate, and long service life.

ZENITH is established in 1987, and its strength in the industry is evident. ZENITH can fully meet the needs of high-end users for creating large production capacity, high efficiency, high intelligence, and high environmental protection crushing sand production projects

1. Large production capacity

Can create large-scale sand and gravel aggregate projects with output of 100-3000 tons per hour or even more for customers in China and abroad.

2. High efficiency

Establishing supplier partnerships with numerous Fortune 500 companies to ensure equipment quality and overall project efficiency.

3. High intelligence

Provide intelligent production solutions to achieve overall optimization from individual equipment to the overall system.

4. environmental protection

Adhere to the principle of prioritizing environmental protection and create a new garden style building materials industrial park.

As an expert in the field of manufactured sand in China, ZENITH provides customized production processes and equipment for customers according to different material characteristics. At the same time, as an industry standard setter, ZENITH knows how to create a green, intelligent and efficient manufactured sand solution for customers. The manufactured sand production line created by ZENITH has a high degree of automation, low operating costs, high crushing rate, energy conservation and environmental protection, large output, simple and convenient maintenance. The finished sand meets to the manufactured sand standards, with uniform particle size, good particle shape, and reasonable grading.