Siroll® XL: chromium-based ceramic rollers resistant to chemical attack
Siroll® XL (Xtra Life) is SIRTEC’s line of ceramic rollers with high resistance to chemical attack. Their chromium base (Cr₂O₃, trivalent chromium) makes them particularly resistant to acid vapours and combustion products, preserving their performance, thermal stability and load-bearing capacity. The solution is designed to last longer, even under the most demanding operating conditions.
Cr₂O₃
THE GRADE
Siroll® XL technical data
The presence of Cr₂O₃ gives the roller the characteristic greenish-grey colour of the XL formulation.
| Characteristic | LP 60 XL | LP 70 XL | LP 80 XL |
|---|---|---|---|
| Composition | standard composition + Chromium (Cr2O3) | ||
| Al2O3 (%) | 75 | 77 | 78 |
| Fe2O3 (%) | 0.40 | 0.40 | 0.30 |
| Bulk density (kg/dm³) | 2.65 | 2.80 | 2.87 |
| Apparent porosity (%) | 20 | 17 | 13 |
| Water absorption (%) | 7.5 | 6 | 4.5 |
| Modulus of elasticity (GPa, 20 °C) | 80 | 105 | >120 |
| Modulus of rupture (MPa) | 50 | 52 | 65 |
| Thermal expansion at 1,250 °C (%) | 0.74 | 0.72 | 0.7 |
| Thermal-shock resistance | very good | very good | very good |
| Identification colour | Green | Blue | Yellow |
THE CHALLENGE
When is a roller resistant to chemical attack required?
It is required when the kiln atmosphere becomes chemically aggressive and accelerates the degradation of standard rollers. This occurs, for example, on digital decoration lines, where digital inks can increase chemical attack on the rollers, together with reactive chemical vapours generated by combustion products in the kiln atmosphere.
Under these conditions, an untreated roller may degrade more quickly, requiring more frequent replacement and increasing the risk of kiln downtime. Siroll® XL was developed to counteract this increased chemical aggressiveness and extend roller service life.
Applications and kiln zones
Siroll® XL is recommended wherever the kiln atmosphere is chemically aggressive:
- Digital decoration lines, where solvent-based inks increase chemical attack on the rollers.
- Environments containing reactive chemical vapours generated by combustion products.
BENEFITS
Features and benefits of chromium-based rollers
Every Siroll® XL feature delivers an in-service benefit:
- Chromium base (Cr₂O₃, trivalent chromium)
- Physical properties remain unchanged
- Longer service life (Xtra Life)
- Available across the entire Siroll® product range
- Technology proven in other industries
Frequently asked questions about Siroll® XL
Why do digital inks increase chemical attack on rollers?
Digital decoration uses inks formulated with organic solvents, carriers and chemical components that undergo decomposition and combustion during preheating and firing. The products of these reactions locally alter the composition of the kiln atmosphere, increasing the presence of chemically reactive species.
Under these conditions, reactive chemical species and other compounds in the atmosphere can interact with the roller surface, promoting corrosion reactions and chemical degradation of the refractory material. This can intensify surface wear, alter roughness, cause deposits to form and progressively impair the roller’s surface characteristics, with possible consequences for tile quality and service life.
The introduction of digital inks, together with changing firing cycles and the rise of large-format products, has therefore created a need for greater chemical resistance in refractory materials.
Siroll® XL was developed specifically for these operating conditions: its chromium-based formulation is designed to increase the roller’s resistance to chemical attack from the kiln atmosphere and preserve its surface characteristics for longer during operation.
Can any Siroll® model be supplied in an XL version?
Yes. Every model in the Siroll® family can be manufactured in a chromium-based XL version. This adds chemical resistance to the model best suited to your kiln zone and production process without compromising its mechanical and thermal properties.
Is the Siroll XL roller a Sirtec invention?
No. Unlike the Siroll HPR and Ti rollers, chromium-based refractories are already used in steelmaking, glass manufacturing and chemical reactors. Sirtec has brought this technology to the ceramic industry to withstand attack from the organic solvents used in digital inks.