Tech Team · Kintek Solution

Yes, crucibles can be cleaned, but the method depends on the type of crucible and the contaminants present. Cleaning typically involves rinsing with distilled water, drying, and heating to high temperatures. For stubborn residues, chemical cleaning using HCl or a mixture of HCl and HNO3 may be necessary, but this requires careful handling under a fume hood. Proper storage and handling are also crucial to prevent damage and contamination.

Key Points Explained:

1. Rinsing and Drying:

   • After cleaning, rinse the crucible thoroughly with distilled water to remove any cleaning agents or residues.
   • Dry the crucible at 110°C for 10 hours to ensure all moisture is removed.
   • Heat the crucible slowly up to 1000°C in an empty run to prepare it for future use.

2. Chemical Cleaning:

   • For stubborn contaminants, start with HCl (≥25 wt%). This is often effective for many types of residues.
   • If HCl alone is ineffective, use a mixture of HCl and HNO3 (1:1 v/v; ≥25 wt%). This mixture is similar to aqua regia and can dissolve more resistant materials.
   • Always perform chemical cleaning under a fume hood to ensure safety, as these chemicals can release harmful fumes.

3. Handling and Storage:

   • Handle crucibles with care using properly fitting tongs to avoid damage.
   • Store crucibles in a dry, cool environment to prevent corrosion or oxidation.
   • Immediately replace any crucibles that are damaged or cracked to avoid contamination or accidents.

4. Preventing Contamination:

   • Use different crucibles for different metals to avoid cross-contamination.
   • Completely empty the crucible after each use to prevent damage from expanding metal residues.
   • Place a plate of cardboard between the furnace base and the crucible before heating to prevent bonding.

5. Regular Maintenance:

   • Regularly clean tungsten crucibles to remove contaminants and maintain their integrity.
   • Inspect crucibles frequently for any signs of wear or damage and replace them as needed.

By following these steps, you can effectively clean and maintain crucibles, ensuring their longevity and performance in various applications.

Summary Table:

Step	Details
Rinsing and Drying	Rinse with distilled water, dry at 110°C for 10 hours, heat to 1000°C.
Chemical Cleaning	Use HCl (≥25 wt%) or HCl + HNO3 (1:1 v/v) under a fume hood for safety.
Handling and Storage	Use proper tongs, store in a dry, cool place, and replace damaged crucibles.
Preventing Contamination	Use separate crucibles for different metals, empty after use, and use cardboard plates.
Regular Maintenance	Clean tungsten crucibles regularly and inspect for wear or damage.

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