Selection of Brick Types and Key Masonry Techniques for Phosphate Brick Linings in Rotary Kilns

I. Current Status of Brick Type Application

In the context of rotary kiln lining projects, both axe-shaped bricks and fan-shaped bricks can be utilized after their dimensions have been designed in accordance with the diameter of the kiln body. Based on current market application trends, axe-shaped bricks account for a larger share of usage, while the application of fan-shaped bricks is relatively less common. Notably, fan-shaped phosphate bricks find some application in white lime rotary kilns, though they are rarely adopted in other types of rotary kilns.

II. Key Points of Masonry Procedure

The service life of a rotary kiln lining depends not only on the selection of the brick type but, more critically, on the appropriateness of the brick dimensions and the meticulousness of the masonry construction.

1. Requirements for Axe-Shaped Brick Masonry

When utilizing axe-shaped bricks for masonry, each ring typically requires the inclusion of 2 to 3 types of key bricks. Regarding the steel plate specifications for these key bricks, reducing the dimensions by 10 mm in both the length and width directions relative to the main bricks is sufficient to meet the keying requirements.

2. Characteristics of Fan-Shaped Brick Masonry

Although the application of fan-shaped bricks is not as widespread as that of wedge-shaped bricks, they offer distinct advantages under specific operating conditions. When laying fan-shaped bricks, there is no need to incorporate "filler bricks" (joggle bricks); instead, circumferential closure is typically achieved by cutting a single brick within each ring.

It is only when masonry work reaches the kiln hood section—or when transitioning to a different brick material—that filler bricks are required. In such instances, bricks that are 10 to 20 millimeters thinner than the main fan-shaped bricks are used for the filling process; specifically, two different thicknesses of phosphate bricks are utilized in the final two rings to ensure tight, dense masonry through compression.

Furthermore, the inner and outer arcs of fan-shaped bricks differ in curvature. Although this difference is slight, the actual masonry procedure still differs marginally from that used for wedge-shaped bricks.

III. Post-Masonry Inspection and Reinforcement

Upon the completion of the phosphate brick masonry, a comprehensive inspection of the kiln body is mandatory. The re-insertion of joint-filling steel plates is of particular importance; based on the loosening observed within the kiln body during rotation—as assessed during the kiln inspection process—these steel plates must be promptly inserted to ensure a tight, compacted fit.

The kiln inspection phase constitutes a critical procedure for ensuring the structural stability of the inner lining; through this process, the phosphate bricks within the kiln body can be further reinforced, thereby effectively extending the service life of the lining.

IV. The Relationship Between Brick Shape and Quality

In summary, the quality control of phosphate bricks intended for rotary kilns is the core factor determining the performance of the inner lining; the selection of the brick shape itself is not the decisive condition.

Provided that the brick dimensions are rationally designed and the construction adheres to established standards, both axe-shaped bricks and fan-shaped bricks are capable of delivering excellent operational performance within a rotary kiln lining, thereby safeguarding the kiln's operational efficiency and service life.