Aluminium & Non-ferrous Aluminium Casthouse · Western Maharashtra

Non-wetting LCC: 3 → 12 months in a corundum-attack environment

Q: Does this work for holding furnaces too?

Yes, with adjusted additive package — holding furnaces see less thermal cycling but more dwell time at metal contact, so the non-wetting package is sized differently. Same family of materials.

Q: What about secondary aluminium with high Mg or Li content?

Mg and Li are far more aggressive than primary aluminium. We'd spec a different additive package — typically heavier on AlF₃ and reduced BaSO₄ — and might recommend a SiC-bonded SiC tile for the metal line in the worst cases.

Q: Can we install this with our own crew?

Yes, but the first install is much smoother with our site engineer present to enforce the dry-out schedule. After that, your crew can self-manage the next install.

A 25-tonne reverberatory melting furnace was failing at 3 months from corundum growth and metal penetration. A non-wetting low-cement castable with engineered BaSO₄ and SiC additions extended lining life to 12 months — a 4× improvement.

Lining life

Before

3 months

After

12 months

Gain

4×

Metal loss to dross

Before

Baseline

After

−18%

Gain

kg/heat

Reline labour cost / yr

Before

₹ 4.2 cr

After

₹ 1.1 cr

Gain

−74%

The Problem

A 25-tonne side-well reverberatory melting furnace was being relined every 3 months. The dominant failure mode was corundum growth (Al₂O₃ build-up from molten-aluminium reaction with the silica content of the lining), with secondary metal penetration through joints. The customer had tried two prior castable suppliers without sustained life improvement, and was carrying ₹4.2 cr/year in reline labour and downtime cost.

Site Survey Findings

What our site engineer measured, sampled, and recorded before specifying any change.

▸ Hot-face castable samples showed massive corundum growth (Al₂O₃ phase formation 8–14 mm thick) at the metal-line and bath-floor interface.
▸ Penetration of liquid aluminium 30–40 mm into the lining was visible at expansion joints and any micro-cracks formed during initial dry-out.
▸ The castable in service was a conventional 6% cement, high-alumina mix — chemistry that is well-known to react with molten aluminium when even small amounts of silica or calcium aluminate are present at the hot face.
▸ Furnace dry-out schedule on previous installs was being compressed to ~36 hours from a recommended 72 hours — accelerating the formation of micro-cracks that fed metal penetration.

The Spec We Proposed

Zone-by-zone re-spec — change only what the wear data justifies, leave the rest alone.

▸ Hot face (metal-line + bath floor) switched to a non-wetting low-cement castable: <2.5% cement, fused alumina aggregate, 4–6% BaSO₄ + 2–3% SiC additions to prevent aluminium wetting and suppress corundum growth.
▸ Side walls above metal line retained as conventional LCC — reaction risk is much lower above the bath, no need to over-spec.
▸ Roof retained as ceramic fibre module construction — already performing acceptably.
▸ Anchor system reviewed — replaced existing 310SS anchors with 314SS to add corrosion margin against the slightly more aggressive aluminium chemistry of the customer's recycle stream.
▸ Dry-out schedule re-imposed at full 72-hour ramp with explicit hold points at 110 °C, 350 °C, 600 °C — supervised by our site engineer for the first install.

Outcome

First installation ran for 12 months before the next planned reline — a 4× life improvement. Corundum growth on post-mortem inspection was visible but limited to 2–3 mm at the hot face, well within tolerance for a second campaign attempt with hot-face touch-up. Metal loss to dross dropped 18% (less metal absorbed into corundum buildup means more metal in the casting). Annual reline cost dropped from ₹4.2 cr to ₹1.1 cr. The customer has standardised on the non-wetting LCC for two further melting furnaces of similar size.

Lessons Applied to Other Plants

What this engagement taught us — now standard practice on every comparable plant we engage with.

▸ For aluminium melting and holding furnaces, non-wetting additions (BaSO₄, SiC, AlF₃ depending on alloy chemistry) are not optional — a conventional LCC will fail at 1/3 the life regardless of brand.
▸ Dry-out discipline is a force multiplier. Compressing a 72-hour dry-out to 36 hours can halve the campaign life of an otherwise correct lining.
▸ Anchor metallurgy matters at the top end of the life curve. Once you've solved hot-face chemistry, anchor failure becomes the next limiter — spec the anchor for the alloy chemistry, not just the temperature.

A note on customer anonymisation: Customer name, exact location, and proprietary process data are withheld at our customer's request as standard NDA practice. Technical details (failure modes, lining specs, before/after metrics, reasoning) are reported as-measured and as-documented in our engagement file.

Frequently asked

Does this work for holding furnaces too? +

Yes, with adjusted additive package — holding furnaces see less thermal cycling but more dwell time at metal contact, so the non-wetting package is sized differently. Same family of materials.

What about secondary aluminium with high Mg or Li content? +

Mg and Li are far more aggressive than primary aluminium. We'd spec a different additive package — typically heavier on AlF₃ and reduced BaSO₄ — and might recommend a SiC-bonded SiC tile for the metal line in the worst cases.

Can we install this with our own crew? +

Yes, but the first install is much smoother with our site engineer present to enforce the dry-out schedule. After that, your crew can self-manage the next install.

Have a similar wear pattern at your plant?

Send us your campaign-life numbers, slag/feed chemistry if available, and a few photos of the failure. We'll come back with a survey plan and an indicative re-spec.

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Non-wetting LCC: 3 → 12 months in a corundum-attack environment

Outcome metrics

The Problem

Site Survey Findings

The Spec We Proposed

Outcome

Lessons Applied to Other Plants

Frequently asked

Have a similar wear pattern at your plant?