Alumina-Magnesia Castable for Ladle Bottom & Sidewall

Alumina-magnesia castable applies the same spinel-forming principle as our corundum-spinel series at a lower cost point. Magnesia in the matrix reacts with alumina in service to form magnesium aluminate spinel, and that reaction carries a small, permanent, positive expansion — which turns out to be exactly what a monolithic lining needs.

Why Slight Expansion Is a Feature

A castable that shrinks on firing pulls away from the shell and cracks. A castable that expands slightly stays in compression against the shell, keeps its shape, and does not develop the gap that lets steel and slag get behind the working face. XZK alumina-magnesia grades are specified with permanent linear change in the +0.2 to +0.8% range at 1500 °C — deliberately positive, deliberately controlled.

This is the same mechanism AMC brick uses to seal its joints, applied to a joint-free lining.

Grade by Zone

• XZK-AMC-90 — 90% Al₂O₃, crushing strength 90 MPa at 1500 °C. Slag line and highest-wear areas.
• XZK-AMC-85 — 85% Al₂O₃, 80 MPa. General working lining.
• XZK-AMC-70 — 70% Al₂O₃, 60 MPa, service to 1650 °C. Permanent and safety lining.

Grading this way is standard practice and is where most of the cost saving in a monolithic ladle package comes from.

Where It Sits Relative to Corundum-Spinel

The two families share a principle but not a specification level. Corundum-spinel (XZK-CH series) runs SiO₂ at 0.5% with crushing strength to 100 MPa and is specified for carbon-critical grades and the most demanding duty. Alumina-magnesia uses the same chemistry logic at a lower cost point, for zones where carbon pickup is less critical but slag resistance and volume stability still matter. If carbon contamination is a genuine reject risk, step up to the corundum-spinel series.

Installation

As with all monolithics, most of the performance is created on site. We issue water addition range, mixing time, vibration method, curing time and a heat-up curve with every order, and can arrange on-site supervision. Storage matters too: material is hygroscopic and must be kept dry, off the ground, and used within the stated shelf life.

Supply

Minimum order 5 metric tons for standard grades and 10 metric tons for custom formulations, shipping in 7–14 days. Precast shapes are quoted to drawing. Batch test data covering density, strength at temperature, permanent linear change and chemistry ships with every lot.

Where This Grade Sits in the Lining System

Monolithic materials fail more often on installation than on specification. Water demand, mixing time, vibration and the first heat-up curve decide the outcome before the lining ever sees metal — which is why installation parameters are issued with the material instead of being left to site practice.

XZK supplies alumina-magnesia castable as one zone of a zoned package rather than as a standalone item: the grades normally zoned alongside it — among them corundum spinel castable — are documented on the monolithic refractories page, and the vessel-level architecture — where each zone starts and ends, and which mechanism actually limits the campaign — is set out on the steel ladle and RH/VD page.

For a complete vessel programme built on this class of material, including the wear survey that set the zoning, see the JFE Steel RH degasser snorkel and ladle flow control programme project reference.