An acid refractory made from quartzite with a small lime bond, fired so that quartz converts to tridymite and cristobalite. It holds load almost to its melting point with very little creep, which is why it builds coke oven walls, glass furnace crowns and hot blast stove domes. Below about 600 C its crystal forms go through sharp volume changes, so silica structures are heated up slowly over weeks and kept hot for their whole campaign.
Silica brick crown on number 3 can't drop below 600 during the hold, keep the burners on low fire.
Never let a silica structure cool through its inversion range during a repair. A coke battery or crown that goes cold is often a rebuild, not a patch.
Also heard as
- silica
- dinas brick
Related terms
Crown
Arched refractory roof of a glass furnace or other large furnace, often built of silica brick.
Creep
Slow, permanent deformation of a refractory under steady load at high temperature over hours to years.
Checker
Brick laid in an open lattice inside a regenerator or hot blast stove to store and return heat.
Expansion joint
Gap deliberately left in a lining so bricks or castable can grow with heat without crushing or lifting.