Selection of Crushing and Screening Equipment for Aggregate Production

Crushing and screening equipment is essential for aggregate production. Given the vast number of manufacturers and the complexity of available models, selecting the right equipment is crucial for optimizing efficiency and reducing operational costs.

Common Crushing and Screening Equipment

Crushing Equipment

• Jaw Crusher: Suitable for primary crushing of large-sized materials.
• Gyratory Crusher: Ideal for high-capacity primary crushing.
• Cone Crusher: Used for secondary or tertiary crushing of hard materials.
• Impact Crusher: Best for materials with medium hardness and less abrasiveness.
• Hammer Crusher: Suitable for crushing brittle materials.
• Roll Crusher: Used for fine crushing of relatively soft materials.

Screening Equipment

• Vibrating Screens: Includes eccentric, inertial, resonant, and electromagnetic vibrating screens.
• Fixed Screens: Includes drum screens, fixed grizzly screens, arc screens, and cyclone screens.

Basic Principles for Equipment Selection

Construction Period

For long-term projects with concentrated aggregate usage, fixed crushing and screening equipment is recommended. For shorter projects with dispersed aggregate needs, especially linear projects like highways, mobile crushing and screening equipment is more suitable.

Aggregate Specifications

For large-sized aggregates, a jaw crusher is recommended for primary crushing. If specific aggregate gradation is required, a combination of crushing and screening equipment should be used, such as a jaw crusher paired with a cone crusher, impact crusher, or hammer crusher, along with appropriate screening equipment.

Material Properties

For hard or medium-hard materials, a jaw crusher is suitable for primary crushing. For medium or soft materials, cone crushers, impact crushers, or hammer crushers can be used directly.

Factors to Consider in Equipment Selection

Economic Indicators

1. Initial Investment: Includes costs for personnel training, equipment packaging, calibration, and certification.
2. Equipment Price and Payment Terms: Important for companies with tight budgets, as it directly affects project continuity.
3. Installation and Relocation Costs: Covers costs for equipment setup, relocation, and site clearance, including materials, labor, and equipment rental.
4. Operating Costs: Includes working and idle time costs, maintenance expenses, and associated blasting production and operation costs.

Technical Indicators

1. Reliability: Equipment should operate continuously for 1,500 to 2,000 hours without mechanical failure.
2. Manufacturing Process: Reflects the technical and management level of the manufacturer.
3. Productivity: Equipment should meet or exceed the project's average production capacity to ensure a buffer.
4. Automation Level: Indicates the equipment's technological advancement and ability to perform operations and quality control automatically.

Material Conditions

1. Type: Analyze representative samples to determine rock type (e.g., limestone, granite, basalt) and mineral composition.
2. Strength: Typically refers to uniaxial compressive strength, classifying rocks into very hard, hard, medium-hard, and soft categories.
3. Hardness: Measured by Mohs hardness scale, ranging from 1 (talc) to 10 (diamond).
4. Moisture Content: Generally required to be ≤2%, not exceeding 5%.
5. Clay Content: Generally required to be ≤1%, not exceeding 2%.
6. Maximum Edge Length: Should be controlled through blasting methods to meet the requirements of the crushing and screening system.
7. Feeding Method: Determine whether to use loaders or direct feeding by dump trucks.

Expected Final Product

1. Total Output: Typically measured in tons per hour. Annual or monthly outputs should consider working days and hours to determine hourly production requirements.
2. Gradation Requirements: Specify aggregate sizes (e.g., 0–5mm, 5–15mm, 15–25mm, 25–40mm) based on project needs and select appropriate screen types and sizes.
3. Particle Shape: Ensure products meet standards for allowable percentages of needle-like and flaky particles.
4. Additional Requirements: Determine if materials need to be washed on vibrating screens.

Supply Considerations

1. Source and Supply Channels: Decide between renting or purchasing equipment, considering regional differences, market maturity, maintenance part compatibility, and supply channels.
2. Delivery Time: Ensure manufacturers have sufficient time to produce equipment without compromising quality, aligning with project schedules.
3. Transportation Methods and Requirements: Different transportation methods incur varying costs and risks. Special requirements reflect the manufacturer's design capabilities.
4. After-sales Service: Includes technical training, spare parts availability, testing, and maintenance services.

By considering these factors, companies can select the most suitable crushing and screening equipment for their specific needs, ensuring efficient operations and optimal production performance.