Choosing the Right Crusher - Shanbao Machinery

Summary：Stone crusher is an indispensable part of crushing, sand making, grinding and other processes. This article will tell you how to select the right crusher for your stone crusher business.

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What's a stone crusher?

A stone crusher is a type of pulverizer that uses mechanical energy to break blocks of stone, concrete, or other building materials into smaller blocks of a specific grain size.

From very hard stones to soft minerals, crushers can be used for a very wide range of materials，they can be utilized in a variety of applications in industries such as mining industry to reduce the size of ore blocks and facilitate their processing，crushed stones previously used as building materials and demolition, crushing the debris left after the demolition of buildings, roads, bridges, canals and various other structures.

How to choose a right stone crusher?

Choosing the appropriate stone crusher is important for every operation, but how to choose a right stone crusher? There are several characteristics to consider:

1. Type and Hardness of Materials

The type and hardness of materials are the first factors to be considered in the selection of crushing equipment. Different types of materials will have different hardness and structure, which will have the primary limit on the selection of stone crusher. Generally, the greater the hardness, the higher the crushing difficulty coefficient.

2. Material Specification

If the material size is large, jaw crusher can be selected as primary crushing; When the size of stone is small and needs to be composed of stone with certain gradation, combined crushing and screening equipment shall be selected.

3. Humidity of Materials

The water content of the material will also affect the selection of the stone crusher. When the water content is too large, the fine materials will agglomerate or stick to the coarse materials due to the increase of humidity, so as to increase the viscosity of the materials, reduce the ore discharge speed and reduce the productivity. When it is serious, it will even block the ore discharge outlet and affect the normal production.

4. Granulometric Requirement

The incoming and outgoing particle size is used to judge the model and crushing level of the required crushing equipment.

5. Output Requirements

The output requirement is an important index to determine the crushing equipment. The higher the output requirement, the larger the required crushing equipment specification, and the corresponding input and output will increase.

6. Construction Site

The specific situation of the construction site is the most direct factor affecting the selection of crusher equipment, such as the site size of the construction site, the specific placement position of crushing equipment, etc.

These are the main stone crushers on the market:

1. Jaw Crusher

The working mode of the jaw crusher is intermittent, and the rock material is crushed by squeezing the rock by the fixed jaw and the movable jaw. Some time ago, a friend left a message to consult the single pendulum jaw crusher. In fact, it is rarely used now, and the compound pendulum jaw crusher is mainly used.

Application: It is suitable for a wide range of materials, both soft and hard, especially the coarse and medium crushing of hard stones.

Advantages: simple structure, reliable work, lighter weight, cheap price, small size, low configuration height, large feed opening size, easy adjustment of the discharge opening opening, simple maintenance, and economical operating costs.

Disadvantages: The liner is easy to wear, and the content of needle flakes in the product is high, and feeding equipment is generally required.

2. Cone Crusher

The work of the cone crusher is continuous, using the eccentric movement of the moving cone to crush the stone. At the same time, due to the tangential movement of the moving cone and the fixed cone, the stone will also be subjected to shearing and grinding. Therefore, its working mechanism It is a combination of extrusion, shearing, and milling methods.

Application: Mainly used for medium or fine crushing of various stone materials. At the same time, according to its different structure (suspended shaft type and supporting shaft type), it can also be used for coarse stone crushing (suspended shaft type is used less).

Advantages: large crushing ratio, high efficiency, low energy consumption, less dust, uniform product size, stable operation, low failure rate, and not easy to be crushed.

Disadvantages: The structure and maintenance are more complicated, the body is high, and the price is expensive.

3. Impact Crusher

Impact crusher is a machine that uses impact energy to crush materials. Adjusting the gap between the counterattack frame and the rotor can achieve the purpose of changing the size and shape of the material discharged.

Application: Mainly used for medium crushing and fine crushing of stones below medium hardness, and the shape of the crushed stones is better.

Advantages: small size, simple structure, uniform product size, selective stone crushing, and high output.

Disadvantages: The blow hammer and the counterattack plate are particularly easy to wear, especially for crushing hard rocks, which are more severely worn and need to be replaced frequently; it is not suitable to crush plastic and viscous materials.

4. Mobile Crusher

Mobile crusher is a new type of equipment. It has been optimized and innovated in structural design, equipment configuration and combined application. The combination is more flexible, which greatly widens the application field of tire mobile crushing station and truly realizes the proximity treatment of materials.

Mobile crushers can be further subdivided into tire type mobile crushers and crawler type mobile crushers. Although they have certain differences in specific structure and operation performance, they both have the characteristics of convenience, flexibility, walking and stopping and local operation:

1. Integrated design of the whole machine. The structure is compact, integrating crushing, sand making, screening and transportation, and the carrying equipment is flexible and diverse.

2. Additional power traction and drive. The locomotive traction or diesel power shall be used for walking, and the operation site shall be transferred at any time according to the demand.

3. Wireless remote control operation. Compared with the traditional fixed crusher, one person can operate it remotely, which saves manpower and worry.

Understanding the crushing stage and the type of crusher best suited for each stage can simplify equipment selection. According to our practical application, the most suitable stone crusher is selected for our quarrying operations.

5. Sand Making Machine

The work of the impact sand making machine is continuous. It uses high-speed moving materials to strike iron, strike each other and friction between the materials to break. There are two crushing methods: "stone-on-rock" and "stone-on-iron".

Application: "Stone-on-Stone" is suitable for abrasive materials with medium-hardness and above. The finished product has a better grain shape and a little more powder content; "Stone-on-Iron" is suitable for materials with low abrasiveness and lower than medium-hardness, with high crushing efficiency. The wear cost of the guard plate is higher, and the finished grain is slightly worse.

Advantages: low energy consumption, high output, large crushing ratio, small size of the equipment, easy operation, convenient installation and maintenance, with shaping function, cubic product, high bulk density, and the machine's counterattack plate wears very much during operation Less.

Disadvantages: The maintenance is complicated and the cost is high. Generally, the maximum feed size does not exceed 60mm, which is suitable for fine crushing and sand making.

6. hammer crusher

The hammer crusher operates on a continuous crushing principle. As the high-speed rotor spins, the attached hammer heads deliver repeated blows to the feed material, effectively breaking down the stones and rocks.

Application: it is suitable for medium and fine crushing of medium and low hardness and non abrasive stones (compressive strength less than 100MPa). It can also be used for sand making when there are grate bars, but it has been rarely used.

Advantages: large crushing ratio, high output and more fine materials.

Disadvantages: the hammer head wears fast, needs to be replaced frequently, raises dust during work, and viscous materials with raw material moisture content greater than 12% cannot pass through effectively.

7. Roller Crusher

The work of the roller crusher is continuous. The stone is located between two parallel cylindrical rollers that move toward each other. The friction force between the stone and the roller bites the stone into the roller, facing the stone of the smooth roller. After being squeezed, the stones on the toothed roller are split and squeezed and broken.

Application: Mainly used for medium crushing and fine crushing of medium hardness stones (compressive strength below 100MPa) such as coal and limestone. Roll crusher is not used in road gravel processing.

Advantages: simple, compact structure, low investment, convenient adjustment, and can be used to crush viscous materials.

Disadvantages: low production efficiency, unable to crush hard materials.

What Is Primary, Secondary, and Tertiary Crushing?

If you want to buy a suitable rock crusher, you also need to know the multi-stage crushing stages is in a complete crushing production line. Stone crushers are classified according to the fineness with which they fragment the starting material. There are primary crushing, secondary (intermediate) crushing and tertiary crushing. Some production lines may include a single crushing stages，the most common production lines involve at least two or three crushing stages.

1. Primary Crushing

As the first stage during a crushing circuit following extraction from a mine site, primary crushing reduces material to a size and shape which will be handled by the secondary crusher. The duty of the first crusher is to form it possible to move material on a conveyer belt . In most aggregate crushing plants, primary crushing is administered during a jaw crusher, although a gyratory crusher could also be used. If material is definitely crushed and not excessively abrasive, an impression crusher could even be the simplest choice as a primary crusher.

2. Secondary (Intermediate) Crushing

In secondary crushing, reduction ratios become an important consideration. Knowing just how fine you would like your final output to be, along side the feed requirements of your tertiary or final reduction crushing station, will assist you determine what proportion reduction must happen within this stage.

Cone crushers are often placed within the secondary crushing station because they're versatile in terms of feed, closed side setting, speed, and throw. With cone crushers, though, it's essential to work them at consistent choked settings to stay productivity up.

3. Tertiary Crushing

In this crushing stage, the standard and quantity of fine products are determined. Quality requirements are often stringent for the ultimate products, especially within the mixture industry. Customer requirements common to both the mixture and mining industries are capacities and quality (fraction/particle size). the mixture industry has additional quality demands like soundness and particle shape (cubicity).

what is the crushing method?

Rock stone crusher is an indispensable part of crushing, sand making, grinding and other processes. However, there are many types of stone crushers on the market. How to choose suitable and satisfactory products?

Understanding the crushing method is very helpful for you to choose the right stone crusher. The crushing method refers to how rock particles are fractured during the crushing process. It is an important factor to consider when selecting the appropriate type of stone crusher.

Before understanding the stone crusher, it is necessary for us to have a simple understanding of the crushing method:

The crushing method of the crusher is divided into compression, splitting, breaking, shearing, impact or blow, etc. Generally, multiple action modes are mixed, and there is no single action mode.

Compression crushing: The working face of the crushing machine exerts pressure on the material sandwiched between it, and the material is crushed when the compressive stress on the material reaches the limit of its compressive strength.

Splitting and shearing crushing: The edges of the crushing working surface are wedged into the material to generate tensile stress inside. When the value exceeds the tensile strength limit of the material, the material splits and locally produces powder at the point of contact between the sharp edge and the material.

Bending and breaking crushing: The materials clamped between the working surfaces, such as simply supported beams or multi-supported beams subjected to concentrated forces, are mainly subjected to bending stress, but are subject to splitting at the contact point of the working surface.

For more information, please visit single stage hammer crusher.

Compression and shearing: a combination of squeezing and shearing.

Impact crushing: Impact crushing includes the impact of the high-speed moving crusher on the material to be crushed, the impact of the high-speed moving material on the fixed wall, and the mutual impact of the moving materials.

This article introduces the key points of selecting a suitable stone crusher, multi-stage crushing and crushing methods, hoping to help you find the most suitable equipment!

Primary crushers reduce large run-of-mine material, such as rocks and ore lumps, into smaller sizes for further processing downstream, whether that be transport to additional crushers or to a wet processing plant. It is the first stage in the crushing process that can sometimes include secondary, tertiary and even quaternary crushing stages, depending on the material and the end product requirements. 

Types of Primary Crushers

There are several types of primary crushers, including:

• Gyratory Crushers
• Jaw Crushers
• Hammermills
• Horizontal Shaft Impact Crushers
• Sizers
• Roll Crushers
• Cone Crushers
• Feeder-Breakers

Gyratory Crushers

Gyratory Crushers are an excellent choice for a primary crusher, as they can handle very hard and abrasive material. They are ideal for dry to slightly wet material but not sticky material.

Gyratories are compression crushers primarily used for heavy mining and quarried materials in extremely high tonnage applications. They provide a reduction ratio of 4:1 to 7:1.

The main features of a Gyratory Crusher include a tall crushing chamber lined with replaceable manganese wear plates, a main shaft with head and mantle, and a spider to anchor the top of the main shaft bearing. They have an adjustable main shaft positioning system and drive assembly, and they are available in a single cylinder or multiple cylinder design.

Material to be crushed is fed into the top of the crushing chamber and compressed between the wobbling mantle in the center and the stationary concave liners covering the inner walls of the chamber. When the material is crushed to the desired product size, it is discharged out the bottom of the crusher. 

One additional benefit of a gyratory crusher is that there is no need for pre-screening or scalping of fines in the feed. The crusher can handle the all-in feed.

The gradation is controlled by adjusting the spacing between the mantle and the concaves at their closest point. For a smaller product size, the main shaft can be raised to create a smaller space between the mantle and the liners. To create a larger product size, the main shaft can be lowered to create a larger space between the mantle and the liners. 

As the machine is set tighter for a finer product, the volumetric throughput of the machine is also lowered. A larger opening equals greater throughput.

Gyratory Crushers typically have a higher capital cost and require a large housing structure that can become a significant engineering investment.

Jaw Crushers

Jaw Crushers are another excellent choice for primary crushing applications because they can accept the toughest, hardest, most abrasive materials. They can handle dry to slightly wet material that is not sticky. 

These types of compression crushers are best suited for heavy mining, quarried materials, sand and gravel, and recycling applications. They provide a reduction ratio of 3:1 to 6:1.

Jaw Crushers feature a moving piece of steel (called the pitman) and a stationary piece of steel that form a V-shaped chamber. Material that enters the chamber is crushed to size between the moving piece of steel and the stationary piece of steel. Most of the crushing action occurs in the bottom third of the chamber. 

In a cycle of the rotating pitman, first the material in the chamber is squeezed to crush the material, then the chamber opens, which allows the material to fall farther down the chamber before the next squeezing cycle comes around.

Sized material discharges out the bottom of the crusher on the open stroke. The product size can be adjusted by moving the pitman closer to or farther from the stationary piece of steel. The closer the pitman to the stationary piece of steel, the smaller the product size. The tighter the setting between the two pieces of steel, the lower the throughput of the machine. This adjustment can be made either hydraulically or manually by adding and removing shims. 

Hammermills

Hammermills can be used as a primary crusher in many types of aggregate and industrial applications, including limestone, marble, shale, gypsum, phosphate, bauxite, aluminum dross, uranium, cryolite, clinkers, quicklime, petroleum coke, coal and more. 

Using a combination of impact, shear and attrition reduction methods, Hammermills tend to generate finer material in addition to size reduction, which may not be desirable for every application. The material enters the crusher and shatters upon impact with swinging hammers that are secured to a spinning rotor. The particles rebound off the breaker plates into the hammer circle and are carried into the grate assembly and across the grate surface, grinding down larger particles. Once the material reaches the appropriate size, it exits through the openings in the grate assembly. 

Output gradation changes are made through speed changes as well as different combinations of grates with various sizes of openings. They are a good tool to use in lower abrasive applications.

Common configurations of Industrial Hammermills are:

• Standard
• Non-Clog
• Centerfeed

Of these three types, the Standard and Non-Clog Hammermill types are considered primary crushers due to the fact that they can accept large feed sizes up to 72” and are capable of milling down to a nominal 3”.

The differences between Standard Hammermills and Non-Clog Hammermills are the breaker plate and the types of materials they process. Standard Hammermills feature a stationary breaker plate and are perfect for free-flowing friable materials with large feed size. Non-Clog Hammermills feature a moveable breaker plate and are perfect for wet, sticky, friable materials with large feed size.

Aggregate Hammermills can be used to generate high-quality, cubical aggregate material with superior soundness or to generate pulverized lime. 

Horizontal Shaft Impact Crushers

Horizontal Shaft Impact Crushers, such as the New Holland, Andreas and MaxCap (which is a hybrid of the two) styles, are typically used for the primary size reduction of soft to medium hard materials. 

These types of impact crushers can handle slightly abrasive, dry or wet material that is not sticky. They provide a reduction ratio of 10:1 to 25:1 and are typically used in quarried materials, sand and gravel, and recycling applications.

Horizontal Shaft Impactors feature a large expansion chamber inside of which is a spinning rotor shaft covered with blow bars or hammers. Material that enters the crushing chamber connects with the spinning rotor, which flings the material at the breaker plates lining walls of the chamber. Much of the breaking of the material occurs upon the initial contact of the material with the rotor and its subsequent impact with the breaker plates. Some additional breakage occurs by the inter-particle collisions as the material is tossed around in the chamber.

Horizontal Shaft Impactor Crushers produce a highly cubical product with enhanced soundness. The gradation is more uniform and can be adjusted by changing the RPM of the rotor. Additional gradation control is provided by adjusting the grates or aprons within the machine. A tighter setting yields a smaller output. A tighter setting also lowers throughput.

One thing to keep in mind, however, is that while Horizontal Shaft Impact Crushers produce more fines than any other type of primary crusher in that stage, they may allow for less fines production in the entire circuit. The more stages of reduction a particle must go through before it is properly sized, the more fines will be produced. Since the primary impactor has a higher reduction ratio, it thus creates more finished product. This results in less reduction needed down the process and thus may result in fines being produced by the entire circuit. 

Sizers

Direct-Drive Crushing Sizers are used for the primary crushing of soft to medium hard material that can be slightly abrasive, dry, or wet and sticky. They are best suited for heavy mining applications and provide a typical reduction ratio of 4:1.

Primary sizers feature two inward rotating rolls that crush the material between the teeth and roll bodies. Already sized material passes between or flows around the rolls, minimizing the generation of fines. 

These types of crushers offer a low profile and high throughput capacities with low roll speeds. Also, like gyratories, they can accept fines in the feed where other compression machines, like jaws, require some pre-screening.

Roll Crushers

Similar to Sizers, Roll Crushers can be used for the primary crushing of soft to medium hard material that can be slightly abrasive, dry, or wet and sticky. They are typically used in heavy mining applications and have a typical ratio of reduction of 4:1.

Primary Roll Crushers are available in several designs:

Roll Crushers are compression-type machines, so output gradation is controlled mainly through the gap setting between the rolls. A wider setting results in a coarser product. A wider setting also provides greater throughput.

Single Roll Crushers feature a low-speed crushing roll that crushes material against a curved crushing plate. They require lower headroom than other primary crushers and produce minimal fines. However, Single Roll Crushers provide limited product sizing and are limited in throughput capacity.

Double Roll Crushers feature two rotating roll shafts that crush material between the teeth and roll bodies. These types of Roll Crushers produce a cubical product with minimal fines generation, and can handle higher capacities.

In the correct application, Triple and Quad Roll Crushers are capable of performing both primary and secondary stages of material reduction in one machine. The top stage of a Triple Roll Crusher has a 6:1 ratio of reduction, whereas the bottom stage has a 4:1.

In a triple-roll configuration, the primary stage of crushing occurs in the top stage of the crusher and features a single roll configuration that performs the initial crushing. A double-roll arrangement on the bottom stage of the machine accepts the sized material from the top stage and sizes it further. It is ideal for handling larger feed sizes due to the design and larger feed opening.

In a quad-roll configuration, both the top and bottom stages have a 4:1 reduction ratio. The primary crushing stage at the top of the machine and the secondary stage at the bottom of the machine both consist of a double-roll arrangement. Due to the feed opening and design of the top stage, these types of Roll Crushers are best for handling medium sized feed material.

Like the other Roll Crushers listed, Triple and Quad Roll Crushers produce a cubical product with minimal fines generation. 

Cone Crushers

Cone Crushers are compression-type crushers that are typically found in secondary crushing stages but can be used as the primary crusher in certain applications. They handle medium hard to very hard, abrasive materials that can be dry or wet but not sticky. Cone Crushers are typically found in quarried materials and sand and gravel applications. They provide a reduction ratio of 3:1 to 5:1.

Material that enters a Cone Crusher is compressed between a wobbling mantle and the concaves inside the crushing chamber. The gradation is controlled by adjusting the spacing between the mantle and the concave at their closest point. This is accomplished by raising and lowering the top or bowl of the crusher. A finer setting will create a finer product but at a lower throughput. 

Speed can also help to determine the final output gradation. Faster speed, for finer feed, is used to produce a finer output.

Feeder-Breakers

Feeder-Breakers, which combine both feeding and crushing into one machine, are used for the primary crushing of friable materials that can be slightly abrasive, dry or wet, but not sticky. They are typically used in heavy mining applications to provide the primary crushing and to make a beltable product to be conveyed for further downstream processing.

These high capacity machines feature a chain and flight drag conveyor that meters material toward a horizontal pick. Run-of-mine material is conveyed toward the rotating pick roll, which crushes the material against the flights and conveyor deck. 

Since Feeder-Breakers size in one dimension only, secondary and even tertiary crushing stages may be necessary to achieve the desired product size. They can be fed by a shovel, truck, loader or dozer and can be made portable for underground operations. 

How To Choose the Right Primary Crusher

While all these machines can be used as primary crushers, they can’t be used interchangeably in every industry. Some types of primary crushers are best suited for hard material, while others are best at handling more friable or wet/sticky material. Some crushers require pre-screening, and some accept all-in feed. Some crushers produce more fines than others.

Primary Crushers Used in Aggregate Applications

The types of primary crushers typically found in aggregates applications include:

• Jaws
• Gyratories
• Impactors
• Cones

Primary Crushers Used in Mining Applications

The types of primary crushers typically found in mining applications include:

• Roll Crushers
• Sizers
• Feeder-Breakers
• Jaws
• Cones
• Impactors

The right primary crusher for an application depends on several factors:

• Material to be crushed
• Feed size
• Desired product size
• Capacity required
• Compressive strength of the feed
• Moisture content

The material and its characteristics, e.g., its hardness, density, shape and condition, will affect the type of crusher that needs to be used. Knowing the material characteristics as well as the advantages and limitations of the different crusher types will help to determine the best primary crusher for a given application.

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