Advantages of Phosphate Bricks:

1. Good Thermal Shock Resistance

They don’t need to be fired and are not prone to cracking with rapid temperature changes. They adapt well to starting and stopping rotary kilns and fluctuating operating conditions, and are less likely to break in large batches.

2. High Strength and Wear Resistance

PA aluminum phosphate bonded bricks have excellent wear resistance at both room and high temperatures, resisting abrasion from clinker and coal powder fumes, making them suitable for kiln ends and transition zones.

3. Easy to Accumulate Kiln Coating

The surface easily attracts kiln coating, which can protect the brick itself and extend its service life (this feature is preferred for the decomposition and transition zones).

4. High Load Softening Temperature

P75 and PA75 bricks can reach load softening temperatures above 1300°C, meeting the requirements for rotary kiln preheating, decomposition, and transition zones.

5. Easy Construction

These are non-fired bricks, so no low-temperature curing or firing is required after construction; they can go straight into kiln drying. They are also relatively easy to cut and shape.

Disadvantages of Phosphate Bricks:

1. Moderate High-Temperature Creep Resistance, Not Suitable for Prolonged Ultra-High Temperatures

Not suitable for long-term exposure in zones above 1400°C; at high temperatures, bricks may deform or blister. In high-temp sections, magnesia-chrome or magnesia-alumina spinel bricks are generally used instead.

2. Poor Alkali Resistance

In production lines with high alkali content, alkali vapors can penetrate and erode the bricks, causing powdering and spalling.

3. Low-Temperature Strength Affected by Moisture

Strength decreases when exposed to water or damp conditions. Bricks must not get wet during storage or construction. During kiln drying, heating must be controlled carefully since rapid water evaporation can cause bricks to bulge or crack.

4. Limited Resistance to Molten Clinker Erosion

Long-term contact with molten liquid can erode the brick surface, so they are unsuitable for high-temperature zones with heavy liquid phases.

5. Strict Kiln Drying Requirements

Kiln drying must be slow to allow water to escape gradually. Rapid heating can easily cause bubbles, delamination, or brick fall.

Simple Rotary Kiln Selection Summary

- Suitable: Preheating zone, decomposition zone, transition zone, kiln ends, cooling zone

- Not Suitable: Main high-temperature firing zone (above 1400°C for long periods), high-alkali and highly corrosive kilns