---
title: "Refractory (castable / brick)"
description: "Refractory linings — castable cement-bonded mixes or pre-formed bricks — protect the steel shells of boilers, rotary kilns, calciners, waste-heat boilers and many other industrial vessels from high-temperature gas and slag attack."
canonical_url: "https://sylio.co/glossary/refractory-castable-brick"
last_updated: "2026-06-28T02:29:35.460Z"
---

**Refractory** linings — castable cement-bonded mixes or pre-formed bricks — protect the steel shells of [boilers](/glossary/boiler), [rotary kilns](/glossary/rotary-kiln), [calciners](/glossary/calciner), [waste-heat boilers](/glossary/waste-heat-boiler) and many other industrial vessels from high-temperature gas and slag attack.

## Castable vs brick

- **Castable refractory** — mixed and poured or gunited in place, like concrete; quick installation, good for irregular shapes
- **Brick refractory** — pre-formed blocks laid in mortar; longest service life, used for the most demanding applications such as cement kiln burning zones

## Why refractory matters for sonic-horn installation

Sonic horns are mounted on the *steel* shell, not on the refractory. Mounting locations must be chosen to avoid disrupting the refractory lining or creating a thermal-stress concentration. Horns mounted near refractory transitions, at kiln-shell penetrations or near burner clusters require detailed installation engineering to avoid initiating refractory failures.

## Cleaning relevance

- Sonic horns do **not** damage refractory — the acoustic field is non-contact
- Aggressive [water cannons](/glossary/water-cannon) and [explosive deslagging](/glossary/explosive-deslagging) **can** damage refractory through thermal shock or impact

## Related terms

- [High-alumina refractory](/glossary/high-alumina-refractory)
- [Rotary kiln](/glossary/rotary-kiln)
- [Furnace](/glossary/furnace)
- [Waterwall](/glossary/waterwall)