A basic refractory made from magnesia and chrome ore, either direct-bonded by high-temperature firing or rebonded from fused grain. It resists iron oxide and silicate slags and thermal cycling well, and is the standard in copper and nickel smelting vessels, steel vacuum degasser snorkels and some secondary steelmaking. Cement kilns avoid it because alkalis convert its chromium to toxic hexavalent compounds, turning spent brick into hazardous waste.
RH snorkels are magnesia-chrome brick, nothing else holds up to that circulation.
Also heard as
- mag-chrome
- direct-bonded mag-chrome
- DB mag-chrome
Related terms
Basic refractory
Refractory based on magnesia, lime or dolomite that resists basic slags with high lime-to-silica ratios.
Spinel
Magnesium aluminate mineral used in chrome-free basic bricks and slag-resistant ladle castables.
Dead-burned magnesia
Magnesia fired so hard it barely reacts with water, the main raw material of basic refractories.
Slag attack
Chemical dissolution and penetration of a refractory by molten slag, the main wear mode in metal processing.