Salt-Alkali Spots and Back Alkali in Mosaic Arabesque Tiles
Causes of Salt-Alkali Spots
1. Coastal Areas
- Sea breeze carries sea mist toward the shore.
- Sea salt (sodium chloride) settles on mosaic arabesque tile surfaces on exterior walls.
- This results in white salt-alkali spots forming over time.
2.Seasonal Salt-Alkali Spots
- During the rainy season in southern regions, increased air humidity causes tiles to absorb moisture.
- Even marble mosaics that usually don’t return to alkali may develop alkali stains under these conditions.
Three Necessary Conditions for Back Alkali Formation
For back alkali to occur in mosaic arabesque tiles, three factors must be present:
- Soluble salt-alkali components (either from the tile itself or external sources).
- Moisture (which dissolves the salt and carries it to the tile surface).
- Channels (such as pores or cracks that allow the moisture to transport the salts).
By addressing these factors, we can effectively prevent and control back alkali issues.
Solutions to Prevent Back Alkali in Marble Mosaic Tiles
1. Selecting the Right Protective Agent
- Choose a protective agent suitable for the type and characteristics of the marble mosaic.
- For lime metamorphic rock tiles, the protective agent must include anti-alkali properties.
2. Protecting Wet-Pasted Marble Mosaic
- Ensure proper protection of the bottom surface of the marble mosaic.
- Do not skip waterproofing even if using a waterproof adhesive.
- Any cut edges made on-site should be sealed with a waterproofing agent.
3. Choosing the Right Protective Agent for Carbonate Marble
- Loose carbonate marble should not be treated with strong alkaline protective agents (e.g., sodium methyl silicate).
- Instead, use a weak alkaline, high-end, environmentally friendly water-soluble protective agent.
- During installation, wipe off any alkali mist from the surface promptly.
4. Ensuring the Tiles Are Completely Clean and Dry
- Before applying a protective agent, the mosaic arabesque tile must be:
- Thoroughly cleaned.
- Completely dry (store at room temperature for at least 4 days after cutting).
- Free of residual moisture—otherwise, protection will be ineffective.
5. Applying Protective Agents Evenly
- Ensure even and thorough application of the protective agent.
- Adjust the dosage based on the tile's water absorption rate for best results.
