---
title: "Clinker cooler"
description: "A clinker cooler (most commonly a grate cooler) quenches hot clinker discharged from the rotary kiln at ~1,400 °C down to ~100 °C using forced ambient air blown upward through a perforated grate. Hot air recovered from the cooler is used as secondary combustion air at the main kiln burner and as tertiary air at the calciner via the tertiary air duct (TAD)."
canonical_url: "https://sylio.co/glossary/clinker-cooler"
last_updated: "2026-06-28T02:29:26.866Z"
---

A **clinker cooler** (most commonly a **grate cooler**) quenches hot [clinker](/glossary/clinker) discharged from the [rotary kiln](/glossary/rotary-kiln) at ~1,400 °C down to ~100 °C using forced ambient air blown upward through a perforated grate. Hot air recovered from the cooler is used as secondary combustion air at the main kiln burner and as tertiary air at the [calciner](/glossary/calciner) via the [tertiary air duct (TAD)](/glossary/tertiary-air-duct).

## Cooler-related fouling

The cooler itself rarely fouls but generates substantial fines that drop out into hoppers below and along the [TAD](/glossary/tertiary-air-duct):

- **Cooler dust hopper bridging** — hopper outlets clog with fine clinker dust
- **Pulse-jet filter pluggage** on cooler vent baghouses
- **TAD bottom dropout** along the air route to the calciner

## Sonic-horn duty

[Sonic horns](/glossary/sonic-horn) installed on the cooler dust hoppers prevent bridging and maintain dust extraction. The horns must tolerate the high-temperature environment immediately below the kiln-discharge zone; stainless-steel construction is standard.

## Related terms

- [Clinker](/glossary/clinker)
- [Rotary kiln](/glossary/rotary-kiln)
- [Tertiary air duct (TAD)](/glossary/tertiary-air-duct)
- [Sonic horn](/glossary/sonic-horn)