In industries such as mining, building materials, and construction waste processing, we often hear the terms "crushing" or "pulverizing." But did you know that turning a huge piece of raw rock into the sand and gravel particles we need is usually not something a single machine can do in one go? It's like a sophisticated assembly line, requiring different types of crushers to perform their specific functions, completing the crushing task stage by stage.
The core of this process is a three-stage crushing system: primary crushing, secondary crushing, and tertiary crushing. Today, we'll delve into the roles of these three stages and the main equipment in each.
1. Primary Crusher – Responsible for the "bold" coarse crushing
Core Task: Performs the first and most crucial size reduction on large pieces of material. It handles huge raw materials (feed size can reach over 1.5 meters) transported directly from quarries or mines, crushing them to a size of approximately 250-300 millimeters.
Operating Characteristics:
• Huge processing capacity: It's the "throat" of the entire production line; its processing capacity determines the scale of subsequent processes.
• High wear resistance and high strength: Must withstand the impact of huge, hard materials.
• Coarse discharge particle size: The goal is to achieve initial "liberation," preparing for the next stage.
Common equipment types:
• Jaw crusher: Like an animal's two "teeth," it crushes materials through a combination of moving and stationary jaws. Simple in structure, robust and durable, it is the most widely used primary crushing equipment.
• Gyratory crusher: Extremely high processing capacity, suitable for large and extra-large production lines. It continuously crushes materials through a rotating cone within the crushing chamber, achieving very high efficiency.
Simply put, the primary crusher is responsible for "creating something from nothing," turning large stones into smaller ones.
2. Secondary crusher – the "backbone" bridging the gap between primary and secondary crushing
Core task: Receives materials from primary crushing and performs further medium and fine crushing. It crushes materials of 250-300 mm to below 60-80 mm, laying the foundation for the final product shaping.
Working Characteristics:
• Emphasis on Particle Shape: While crushing, attention is paid to the shape of the produced aggregate (cubic content), which is important for the strength of materials such as concrete.
• Balancing Efficiency and Fineness: It serves as a bridge between coarse and fine crushing.
Common Equipment Types:
• Cone Crusher: Utilizes the principle of layered crushing, crushing materials through compression and bending forces. It has good wear resistance and is suitable for crushing medium to high hardness materials (such as granite and basalt), producing excellent particle shape.
• Impact Crusher: Utilizes high-speed rotating rotors with hammer plates impacting the material, giving it kinetic energy to strike the impact plate and crush it. Its advantages include a large crushing ratio and good product particle shape, but wear parts wear relatively quickly, making it more suitable for medium to low hardness materials.
In short, the secondary crusher is the first step in "fine processing," transforming small stones into more uniform aggregate.
3. Tertiary Crusher (Sand Making Machine) – Pursuing "Perfection" in Shaping and Sand Making
Core Task: This is the final step in the entire process, aiming to produce high-quality finished products that meet stringent standards. It further crushes and shapes the material after secondary crushing (<60mm), ultimately producing 0-5mm manufactured sand or high-quality stone of various specifications.
Working Characteristics:
• The core is "shaping" and "sand making": the goal is to increase the cubic content of the product, reduce needle-like and flaky particles, and achieve an ideal gradation in the sand.
• Precise control: The output particle size can be flexibly adjusted to meet the needs of different customers.
Common Equipment Types:
• Impact Crusher: Currently the most mainstream sand making equipment. It uses the "stone-on-stone" or "stone-on-iron" principle, achieving crushing and shaping through the impact and friction of the material within the crushing chamber, producing sand with rounded particles and excellent gradation.
• Vertical Shaft Impact Crusher: Similar in principle to the above, it is a core piece of equipment in the sand making field.
• Sometimes, fine jaw crushers or short-head cone crushers can also be used for tertiary crushing.
In short, a tertiary crusher is the final step in "turning stone into gold," transforming ordinary stone into high-value, high-quality sand and gravel aggregate.
Summary: How to Choose?
Choosing the right crusher combination depends on the properties of your raw material (hardness, moisture content, mud content), expected output, and the requirements of the final product (particle size, particle shape).
• Classic granite/basalt production line: Jaw crusher (primary) + Cone crusher (secondary) + Impact crusher (tertiary).
• Limestone/medium hardness production line: Jaw crusher (primary) + Impact crusher (secondary/tertiary stages are possible; sometimes a separate tertiary crushing stage can be omitted).
Understanding the pision of labor and collaboration among primary, secondary, and tertiary crushers is the first step in planning an efficient and economical crushing production line. Hopefully, this blog post will help you build a clear understanding!
Are you looking for the right crushing solution for your project? Contact us; our experts will provide you with personalized equipment selection advice!
