1. Preparation and Surface Treatment Before Repair
Shutdown and Evacuation: Close the feed valve and thoroughly empty the hydrocyclone to remove residual starch slurry and prevent contamination.
Disassembly and Inspection: Mark worn areas (such as the underflow outlet, cone section, and inner wall of the hydrocyclone tube) and assess the extent of damage.
Surface Treatment:
Welding Reinforcement: Reinforce the damaged metal substrate with steel plates or reinforcing bars of the same material using welding.
Degreasing and Moisture Removal: Bake the surface with an oxy-acetylene flame (10cm long flame, 5cm/min speed) to remove grease and moisture.
Sandblasting and Rust Removal: Remove the oxide layer using sandblasting to reveal a uniform metallic color. After sandblasting, apply moisture-proof treatment to prevent secondary contamination.
2. Selection of High-Performance Wear-Resistant Repair Materials
Based on the stress characteristics of the worn areas, select suitable composite materials for coating and repair:
RJ-YHL-C-1.0-2.0 Composite Ceramic Wear-Resistant Repair Material: Suitable for areas with light wear, possessing excellent erosion resistance.
RJ-YHG-C-3.0-3.5 Special Wear-Resistant Repair Material: Used in high-wear areas (such as underflow inlets and feed inlets), with strong impact resistance.
RJ-C-100 Wear-Resistant Repair Material: Used as a sealing material to improve overall density and corrosion resistance; applicable temperature range: -20℃ to 250℃.
✅ Application Points:
Strictly follow the mixing ratio for material preparation. Use within 3 minutes after thorough stirring to avoid curing failure.
When applying, press firmly in one direction. Before initial curing, use a scraper to smooth the surface smoothness.
When the air temperature is below 15℃, component A can be heated to 30~40℃ to facilitate stirring.
3. Heating Curing and Grinding Acceptance
Heating Curing: After application, allow the surface to stand for 30 minutes. Then, increase the temperature in stages according to the curing schedule (e.g., 60℃/2h → 80℃/2h → 100℃/2h) to ensure complete cross-linking of the material.
Grinding Treatment: After curing, use specialized tools to grind the repaired surface to restore its original dimensional accuracy and ensure stable flow field.
Trial Operation Verification: Before commissioning, gradually increase the load from 50% to full load, observing for any leaks, vibrations, or abnormal sounds.
4. Long-Term Protection Recommendations
A ceramic epoxy coating or polyurethane spray can be applied on top of the repair layer to form a composite protective layer, extending the service life by 1–2 years.
For frequently worn areas (such as sedimentation tanks), high-toughness ceramic sheets can be bonded to form a "composite armor" structure, significantly improving erosion resistance.
✅ Practical Results: After being repaired with a wear-resistant coating, the service life of the sedimentation tank in an alumina plant was extended from 6 months to more than 2 years, significantly reducing the rate of unplanned downtime.
