Magnesia Gunning Mix for BOF, EAF and Ladle Maintenance

Magnesia gunning mix is the cheapest campaign life you will ever buy — provided it is used for what it is. It is a maintenance tool for levelling a wear profile, not a fix for a zone that was specified with the wrong grade.

What Gunning Actually Buys You

A lining comes down when its thinnest zone reaches the safety lining. Everything else — every other course with 60 mm still on it — is thrown away at that moment. Restoring the thin zone in service means the vessel keeps running on the thickness that is already there. That is the entire economic argument for gunning, and it is a strong one when the wear profile is uneven.

Where the wear profile is even, gunning buys much less, because there is no single zone holding the campaign back. This is why we ask about your wear pattern before recommending a gunning regime.

Why SiO₂ Content Matters Here

Gunning mixes need a bond that develops quickly at the gunned surface but does not melt at service temperature. Silica helps bonding, but too much of it forms low-melting phases with FeO and CaO at 1500 °C and above — and a patch that softens will slough off within a few heats, taking the repair cost with it. Holding SiO₂ to 8% maximum keeps the patch dimensionally stable while still achieving a working bond.

Hot MOR Is the Number to Check

Cold strength is easy to quote and largely irrelevant here. What determines whether a patch survives is hot modulus of rupture at service temperature — how well the material resists slag wash and thermal cycling while hot. XZK-MG-80 is specified at ≥4 MPa at 1500 °C, which is a working figure for slag-line and hot-spot repair rather than a laboratory curiosity.

Getting Rebound Under Control

Rebound is material that hits the wall and falls to the floor. It is pure waste, and it is usually caused by a mismatch between mix grading and gunning equipment rather than by a bad product. Nozzle pressure, water addition, nozzle angle and standoff distance all matter. Give us the machine make and model and we will grade the mix to suit — that single adjustment often recovers more material than changing supplier would.

Supply

Supplied in 25 kg moisture-barrier bags on ISPM-15 pallets or 1,000 kg big bags, date-stamped. Minimum order 5 metric tons. Every batch ships with chemical analysis and physical test data, and a written gunning procedure covering water addition, nozzle distance and angle, and layer thickness.

Where This Grade Sits in the Lining System

Carbon-bonded basic grades are never specified in isolation. Carbon level, antioxidant package and bulk density are all set by the zone, and the zone map is set by the vessel — which is why a grade that performs well in one position can fail early in the next.

XZK supplies magnesia gunning mix as one zone of a zoned package rather than as a standalone item: the grades normally zoned alongside it — among them magnesia carbon brick — are documented on the magnesia-carbon and basic 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 BOF converter and electric arc furnace pages.

Campaign data measured on this class of lining — including the wear profile that drove grade selection — is published in the ArcelorMittal Kryvyi Rih 300 t BOF lining programme project reference.