What Screening and Washing Techniques Optimally Remove Fines from Crushed Stone Output?

Timp: 23 February 2021

Removing fines (small particles like dust) from crushed stone output is an important part of producing high-quality aggregates for construction and other applications. Several screening and washing techniques can be used effectively to separate fines from crushed stone. The optimal technique depends on the material characteristics, production rate, and desired level of cleanliness. Below are some widely used methods:

Screening Techniques

1. Vibratory Screens:

   • Vibrating screens use vibratory motion to sift materials and separate fines.
   • They are equipped with different screen meshes or decks to classify materials based on particle size.
   • High-frequency vibrating screens can enhance the separation efficiency for fine particles.

2. Grizzly Screens:

   • Grizzly screens (static or vibrating) are designed to remove larger debris and fines early in the process.
   • Helps pre-screen larger aggregates from finer materials, preventing clogging in subsequent equipment.

3. Rotary Trommel Screens:

   • Trommel screens rotate to separate particles based on size.
   • These cylindrical screens excel at removing fines while minimizing dust.

4. Flip-Flop Screens:

   • A specialized type of vibrating screen that uses flexible screen mats supported by rubber mounts.
   • Ideal for sticky materials or aggregates without clogging, and effective in removing fines.

5. Inclined Screens:

   • Angled screens use the force of gravity to move material, enhancing the separation of fines.
   • Can work with either wet or dry materials.

Washing Techniques

1. Spray Bars:

   • Spray bars with high-pressure water jets are installed on vibrating screens or conveyors.
   • Water washes away fines and dust from the crushed stone, improving cleanliness.

2. Log Washers:

   • Log washers use rotating paddles to agitate the material in a water bath.
   • They are highly effective for removing stubborn clays and finer particles from aggregates.

3. Sand Classifiers and Hydrocyclones:

   • Employ centrifugal forces to separate fines from the desired aggregates.
   • Often paired with washing systems to enhance the removal of unwanted fines.

4. Washer Drums or Scrubbers:

   • Rotating drums with water or a combination of water and abrasives help loosen and remove fines.
   • Particularly effective for cleaning coarse crushed stone.

5. Bucket Wheels/Dewatering Screens:

   • These systems combine washing with dewatering to remove fines and improve moisture content of aggregates.

Optimization Tips

• Combination of Screening and Washing:

  • Combining multiple techniques, such as vibratory screens followed by spray bars or log washers, can drastically improve efficiency.

• Pre-Screening:

  • Use grizzly screens or scalping screens early in the process to remove oversized material and prevent unnecessary fines from entering further stages.

• Material Test and Analysis:

  • Test the characteristics of the crushed stone (particle size distribution, moisture content, clay content) regularly to optimize the screening/washing setup accordingly.

• Closed-Loop Systems:

  • Recycling wash water with settling tanks or filter presses can reduce water consumption and cost.

By selecting and optimizing the right combination of screening and washing techniques, operations can effectively remove fines from crushed stone output and achieve desired product specifications.

Contact Us

Shanghai Zenith Mineral Co., Ltd. is a leading manufacturer of crushing and grinding equipment in China. With more than 30 years of experience in the mining machinery industry, Zenith has built a strong reputation for delivering high-quality crushers, mills, sand-making machines, and mineral processing equipment to customers around the world.

Headquartered in Shanghai, China, Zenith integrates research, production, sales, and service, providing complete solutions for aggregates, mining, and mineral grinding industries. Its equipment is widely used in metallurgy, construction, chemical engineering, and environmental protection.

Committed to innovation and customer satisfaction, Shanghai Zenith continues to advance in intelligent manufacturing and green production, offering reliable equipment and comprehensive after-sales service to help clients achieve efficient and sustainable operations.

website: https://www.chinagrindingmill.net

E-mail:info@chinagrindingmill.net

Whatsapp:+8613661969651

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