Scientific Drying and Firing Parameter Control to Minimize Brick Breakage Rate
Brick breakage during the drying and firing process remains one of the most prevalent and profit-damaging quality problems in modern brick manufacturing. Uncontrolled moisture evaporation, improperly designed temperature rise curves, and uneven heat distribution inside drying chambers and kilns are the leading causes of brick cracking, spalling, chipping, and structural breakage. Precise, science-based process control across the entire drying and firing workflow is the most reliable method for brick manufacturers to stabilize product quality, minimize production waste, lower operational costs, and improve overall factory production efficiency.
In the drying stage, inconsistent moisture gradients are the primary cause of green brick breakage. After extrusion and molding, newly formed green bricks retain a high volume of internal free moisture. Rapid surface drying creates a hard, rigid outer layer that traps internal moisture, preventing uniform evaporation. Accumulating water vapor generates strong internal tensile stress, which forms micro-cracks and eventually leads to severe brick breakage during the high-temperature firing stage. To resolve this issue, manufacturers must adopt a scientific staged gradient drying strategy. During the early low-temperature drying phase, factories maintain a stable workshop temperature of 90–120°C with low airflow and high relative humidity, enabling synchronized moisture evaporation from both the surface and inner core of green bricks. In the mid-to-late drying stages, operators gradually reduce humidity and increase ventilation to accelerate the discharge of residual moisture. Strictly controlling the final residual moisture content below 6%–8% effectively eliminates steam expansion risks and prevents brick cracking during firing.
Professional stacking and brick arrangement techniques significantly improve drying uniformity and reduce breakage rates. Layered single-row stacking outperforms dense overlapping stacking by optimizing hot air circulation and eliminating inconsistent drying speeds between inner and outer brick layers. Regular brick stack turning and position balancing ensures uniform moisture evaporation across all production batches. This standardized stacking practice greatly reduces batch-to-batch quality differences and lowers overall brick breakage during drying and subsequent firing procedures.
During the firing process, thermal shock and unstable temperature fluctuations are the dominant factors causing finished brick breakage. The preheating zone of the tunnel kiln is the highest-risk section for brick damage. Manufacturers must maintain a steady heating rate of 6–8°C per hour, with a maximum supply air temperature of 116°C. Rapid temperature elevation causes violent vaporization of residual internal moisture, resulting in burst cracks and structural failure. Additionally, regular exhaust fan calibration is essential to stabilize internal kiln air volume and air pressure. Effective kiln inlet sealing prevents cold air intrusion and local condensation, which are common triggers of uneven thermal shrinkage and brick breakage.
Stable constant-temperature operation in the high-temperature firing and heat preservation zone is critical for producing high-strength, crack-free bricks. Consistent firing temperatures promote uniform mineral crystal transformation and body densification, preventing loose brick structures and over-burning damage caused by temperature deviations. After completing the firing cycle, slow, uniform cooling is mandatory. Abrupt rapid cooling creates extreme internal temperature difference stress, forming invisible micro-cracks that expand during transportation, packaging, and end-use, leading to late-stage brick breakage.
By implementing standardized drying and firing parameter systems, adopting precise staged temperature and humidity control, and maintaining a stable internal kiln thermal environment, brick manufacturing plants can reduce drying and firing breakage rates by over 80%. This optimized process management drastically improves finished product yield, reduces raw material waste, and cuts down energy consumption and overall production costs.
