Material Evolution and Selection Key Points for Wind‑Guide Wall Bricks of Pellet Shaft Furnace

Material Evolution and Selection Key Points for Wind‑Guide Wall Bricks of Pellet Shaft Furnace

1. Service Condition Orientation and Performance Requirements of Wind‑Guide Wall Bricks
Wind‑guide wall bricks are composite refractory products installed at the water‑beam section of pellet shaft furnaces, which are required to deliver combined properties including wear resistance, erosion resistance and thermal shock resistance.
The water beam in the shaft furnace performs multiple functions: load‑bearing, supporting the wind‑guide wall and guiding gas flow. Therefore, wind‑guide wall bricks rank among the most critical components of shaft furnace linings. Their service life generally aligns with the overhaul cycle of water beams, approximately 1.5‑2 years.
Located in the high‑temperature zone of the shaft furnace, water beams are protected by internal circulating water cooling. During furnace shutdown and furnace baking, water beams together with wind‑guide wall bricks undergo repeated thermal shock from rapid heating and cooling. Such drastic temperature fluctuation constitutes the primary factor limiting brick service life.
2. Influence of Water‑beam Material on Wind‑guide Wall Brick Selection
Common materials for shaft‑furnace water beams include carbon steel, nickel‑chromium steel, stainless steel and boiler steel.
Water beams made of stainless steel tubes feature relatively long service life. Nevertheless, most manufacturers adopt carbon steel or boiler steel for cost control. Different water‑beam materials directly determine their service cycles, which in turn impose differentiated requirements for wind‑guide wall brick materials.
The service life of wind‑guide wall bricks shall match that of water beams, so as to avoid resource waste caused by insufficient or redundant material performance.
3. Material Evolution of Wind‑Guide Wall Bricks
Along with changes in operating conditions of pellet shaft furnaces and upgrading of water‑beam materials, wind‑guide wall bricks have gone through three generations of technical evolution.
Generation 1: Yellow Corundum Bricks
Early‑stage wind‑guide wall bricks adopted yellow corundum. By introducing corundum components into bauxite‑based raw materials, resistance against rapid temperature change and dust scouring was improved, satisfying basic operating requirements for water beams at that time.
Generation 2: Semi‑Zirconia Bricks
As service requirements became more stringent, the second‑generation semi‑zirconia bricks were developed. Around 8 % zirconia oxide is added to alumina‑based matrix, which greatly enhances wear resistance and scouring resistance of bricks, suitable for service environments with moderate erosion intensity.
Generation 3: Corundum‑SiC Composite Bricks
When some end‑users deployed stainless‑steel‑tube water beams for extended service life, the third‑generation corundum‑silicon carbide (SiC) composite bricks were developed. Its performance matches the long‑cycle service requirement of water beams, realizing consistency between brick service life and water‑beam overhaul interval.
4. Technical Advantages and Application Status of Corundum‑SiC Composite Bricks
Compared with semi‑zirconia bricks, corundum‑SiC composite bricks exhibit superior wear resistance and markedly improved thermal‑shock stability, while keeping market prices at comparable levels. Thanks to outstanding comprehensive service performance, this material has become the mainstream option for wind‑guide wall bricks.
Corundum‑SiC composite wind‑guide wall bricks currently account for over 80 % of market share. They deliver optimal overall performance in service life, resistance to thermal cycling and dust erosion, and serve as the preferred refractory material for wind‑guide wall sections of pellet shaft furnaces.
5. Conclusion
Material selection for wind‑guide wall bricks shall fully take water‑beam material, operating temperature and thermal‑shock conditions into consideration. Featuring excellent wear resistance, thermal‑shock resistance and favorable cost‑effectiveness, corundum‑SiC composite bricks represent the mainstream configuration for wind‑guide walls of modern pellet shaft furnaces, and are of great significance for ensuring long‑term stable operation of shaft furnaces.