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How to Reduce Brick Breakage Rate During Drying and Firing Process?

2026-07-15

High brick breakage and cracking rate is one of the biggest profit killers for overseas brick factories. Many new brick plants suffer from 8%–20% brick loss rate due to improper drying and firing control, which directly raises production costs and cuts down net profit.

This professional guide shares practical, factory-tested methods to reduce brick breakage in drying and firing stages. All solutions fit fully automatic and semi-automatic tunnel kiln brick production lines

1. Main Causes of Brick Cracking and Breakage

Most brick defects happen in two critical stages: uneven drying shrinkage and excessive temperature difference during firing. Common reasons include unreasonable raw material moisture, wrong brick stacking method, rapid temperature rise, poor kiln airflow and immature aging process.

2. Reduce Breakage in the Drying Process (Key Pre-Firing Stage)

More than 60% of brick cracks are formed in the drying stage, not during firing. Controlling drying speed and uniformity is the most cost-effective way to lower brick scrap rate.

2.1 Control Raw Material Moisture and Aging Time

Unbalanced moisture inside brick blanks causes inconsistent shrinkage. For standard clay, shale and mixed raw materials, keep the forming moisture between 18%–24%. Extend material aging time to 24–48 hours to ensure even water distribution and plasticity stability.

Effect: Effectively eliminate irregular surface cracks and blank breakage before entering the dryer.

2.2 Adopt Gradient Slow Drying Mode

Many new factories make the mistake of fast high-temperature drying. Rapid surface water loss leads to surface hardening while the inner layer remains wet, causing burst cracks.

Set staged drying parameters: low temperature and high humidity at the initial stage, gradual temperature rise and dehumidification in the middle stage, and thorough drying in the final stage.

2.3 Standardize Automatic Brick Stacking Method

Disordered stacking blocks hot air circulation, resulting in partial under-drying and over-drying. Keep uniform gaps between brick layers to ensure 360° hot air flow. Avoid dense stacking at the edge of the drying car.

3. Reduce Brick Breakage in the Tunnel Kiln Firing Process

Firing breakage mainly comes from temperature shock, uneven kiln temperature and unreasonable fuel combustion. Stable temperature curve management can control the firing scrap rate below 3%.

3.1 Avoid Rapid Temperature Rising and Cooling

Brick blanks are fragile before sintering. Sharp temperature increase will produce huge internal thermal stress and cause layered cracking. Strictly follow the standard heating curve: slow heating, constant temperature sintering and slow cooling.

3.2 Balance Kiln Internal Airflow and Temperature

Local overheating or cold zones inside the tunnel kiln are common causes of deformed and broken bricks. Optimize the hot air circulation system and waste heat recovery system to ensure consistent temperature in all kiln zones.

3.3 Optimize Fuel Combustion Efficiency

Incomplete combustion leads to unstable fire power and temperature fluctuation. No matter using coal, natural gas or heavy oil, keep sufficient oxygen supply and uniform combustion to avoid local temperature deviation.

4. Raw Material Formula Optimization to Lower Breakage Rate

Single pure clay material has large shrinkage coefficient after high-temperature firing. Proper material mixing can greatly improve brick stability.
Mix 20%–40% shale into clay to reduce overall shrinkage rate
Add 10%–30% coal gangue or fly ash to balance internal stress
Remove large stone and hard impurities to prevent local stress concentration

5. Daily Operation Management Standards

Regularly check dryer and tunnel kiln sealing to avoid cold air intrusion
Keep stable production speed and avoid frequent line start-stop
Train workers on standardized stacking and parameter adjustment
Record daily breakage data to track abnormal fluctuations

What Automation Level Should I Choose for My Brick Plant? Semi‑Auto vs Full‑Auto Complete Decision Guide

How Can Daily Operation and Routine Maintenance Extend Your Clay Brick Making Machine’s Service Life?

Coal Gangue: Realize Internal Combustion and Reinforce Brick Body

Coal gangue brings two core benefits for clay brick manufacturing: internal combustion function and structural skeleton support.

Key strengths:

1. Self‑heating property: Residual carbon contained in coal gangue burns inside tunnel kilns. This internal combustion effect drastically cuts external coal input and lowers firing cost. This is its biggest advantage in brick production lines.
2. Low‑cost industrial solid waste: Coal gangue is coal‑mine waste. Many local suppliers offer low‑cost supply. Enterprises can apply for preferential tax policies for comprehensive utilization of solid waste resources.
3. High mechanical performance: Under scientific batching, finished fired perforated bricks achieve MU15‑MU25 strength, fully satisfying load‑bearing masonry standards.
4. Enhanced thermal insulation performance: After carbon is fully burned away, micro‑voids form inside brick units, reducing thermal conductivity compared with pure clay bricks.

Critical production reminders for coal gangue:

*Recommended mixing ratio: maximum 30%. Higher dosage raises defect risks.
*Particle size must be ground below 0.25 mm. Large particles will trigger lime popping damages.
*Avoid raw coal gangue with excessive CaO content, which causes brick cracking and surface efflorescence.
*Complete raw material chemical analysis before feeding. Preferred range: SiO₂ 50%‑70%, Al₂O₃ 10%‑20%.
*Prepare flue‑gas desulfurization equipment if incoming material features high sulfur content.

Kaolin: High‑Grade Modifying Material Without Heat Generation

Kaolin improves brick quality indexes, yet it cannot generate heat during kiln firing.

Merits of kaolin:

1. Rich Al₂O₃ stimulates mullite phase formation at high temperature, improving brick strength and ceramic texture.
2. Excellent whiteness supports light‑toned decorative bricks and fair‑faced bricks.
3. Boost long‑term durability and chemical resistance of brick products.

Shortcomings of kaolin:

1. No calorific value. Adding kaolin cannot save firing fuel and increases material expense.
2. Purchase cost is much higher compared with coal gangue.
3. Plasticity is inferior to common clay. Over‑addition creates serious moulding troubles during extrusion.

For ordinary load‑bearing fired perforated bricks, kaolin is overqualified. It is best applied for premium decorative brick series, or small‑volume supplementation when original clay lacks Al₂O₃ content.

Combined Blending Solution

Manufacturers can combine both raw materials if site conditions permit. Coal gangue takes charge of internal combustion, and kaolin upgrades product quality. When comparing individual additive performance, coal gangue presents much higher cost‑efficiency for perforated brick mass‑production.

What Is the Best Low‑Cost Clay Brick Extruder for Small‑Scale Brick Plant Startup?

Starting a small fired brick manufacturing plant always brings many practical challenges for new brick investors. Many project owners struggle with balancing production capacity, power consumption, raw material compatibility and total investment budget.

Most new brick factories do not need large‑scale vacuum extrusion lines at the initial stage. High‑power vacuum brick machines mean heavy capital input, higher electricity bills and complex daily maintenance, which creates financial pressure for medium‑budget brick workshops. A large number of brick entrepreneurs are searching for reliable non‑vacuum brick making machine that can handle multiple local raw materials while keeping operating costs low.

When selecting brick extruder equipment, three core factors should be evaluated first.

Raw material adaptability: Local soil conditions vary greatly across regions. Good brick machinery should process clay, red soil and fly ash without complicated pre‑treatment.
Energy consumption: Continuous production makes power cost one of the biggest recurring expenses for brick plants. Low‑power yet stable extruders effectively cut long‑term operation expenditure.
Scalable capacity: Small brick factories hope to expand output later without replacing the whole main host machine.

The JZ series non‑vacuum brick extruder is designed to solve these pain points for small and medium brick plant operators. This product line covers multiple models: JZ250, JZ280, JZ300, JZ350 and JZ400. The auger diameter ranges from 250 mm to 400 mm, with production capacity from 7.5 t/h up to 25 t/h. The extruder power varies from 11 KW to 55 KW to match different project scales.

✅ Wide raw material compatibility: It works well with clay, red soil, fly ash and similar brick‑making materials, not limited to pure clay resources.

✅ Low energy consumption: For example, the hot‑selling JZ300 model only runs on 30 KW extruder power, delivering stable 15 t/h output for solid bricks.

✅ Compact workshop‑friendly structure: Simple manual clutch design lowers operation difficulty for local workers. It mainly produces high‑quality solid bricks, and can also manufacture small‑hole hollow bricks. For large‑hole hollow brick production, higher‑power extrusion equipment is recommended.

✅ Perfect match for Hoffman kiln: This series is widely paired with Hoffman kiln for traditional fired brick production, ideal for family workshops and medium‑budget brick yards.

From Semi‑Manual Operation to Smart Packaging: Why Full‑Automatic Brick Packing Solutions Benefit Brick Plants？

Many brick factories once relied on semi‑automated workflows for brick unloading and packaging. The semi‑automatic brick packing unit represented an improvement from pure manual work within the history of fired clay brick packaging. Still, plant managers gradually realized its obvious drawbacks in real‑world mass production.

Semi‑automatic machines mixed mechanical movements with manual assistance. It relieved part of heavy labor, yet key steps still needed workers on site. Human participation limited line speed, created inconsistent strapping results, and kept labor expenditure at a high level. For long‑term business development, these points became hard‑to‑solve pain points for brick production line automation.

For modern brick‑making enterprises, our full‑automatic automatic brick packing machine delivers practical, problem‑solving smart packaging performance. This complete brick unloading strapping system consists of five core modules: automatic brick unloading system, post‑unloading brick conveying system, brick grouping unit, brick palletizing system, and automatic arrow‑penetrating strapping & packaging unit.

Controlled by high‑end PLC‑HMI intelligent control platform with touch‑screen interface, the whole set runs automatically. Operators can complete setting and monitoring via human‑machine interface instead of frequent on‑site manual handling.

Without manual intervention for core unloading, grouping, stacking and strapping work, factories gain consistent packaging quality batch after batch. Continuous high‑speed running greatly raises overall line output. Even though the one‑time purchase cost is higher than semi‑automatic options, enterprises will cut total operational cost in the long run thanks to labor reduction.

Another competitive advantage lies in powerful adaptability. The full‑automatic system supports parameter modification for various brick sizes and styles. Smart upgrades including remote equipment monitoring and fault self‑diagnosis minimize unexpected stops. The modular design also makes it flexible for renovation projects for plants with different layouts and output targets.

To conclude, semi‑automatic brick packing equipment played a transitional role during industry transformation. If brick manufacturers want to break cost and capacity limits, full‑automatic smart automatic brick packing machine is the future‑oriented choice to realize stable output, standardized packaging and intelligent manufacturing for brick factories.

How to Invest in A Profitable Vacuum Brick Extruder Production Line

The global clay brick manufacturing industry is undergoing unprecedented structural upgrades in 2026, driven by low-carbon policies, automated production upgrades, and booming global construction demand. According to authoritative industry data, the global clay brick market was valued at USD 65.6 Billion in 2024 and is projected to reach USD 76.4 Billion by 2030, maintaining a steady 2.6% CAGR. Unlike the traditional extensive brick-making mode, modern brick factories are eliminating backward high-energy-consumption equipment and embracing high-efficiency, energy-saving, and low-emission production systems, making high-quality vacuum brick extruder the core investment hotspot for global brick plant investors.

In recent years, major changes in the global brick industry have reshaped equipment procurement standards for manufacturers worldwide. First, EU ETS carbon tax and Carbon Border Adjustment Mechanism have raised strict carbon emission requirements for construction building materials. European, Middle Eastern, and Southeast Asian brick factories are phasing out old soft-tooth low-efficiency extruders that consume high power and produce defective bricks in large quantities. Second, the global construction industry is shifting towardmodular and prefabricated buildings, driving surging market demand for high-precision split-face terracotta bricks, hollow insulation bricks, and paver bricks. Third, many countries have issued mandatory industrial upgrading policies, forcing backward production lines with low annual output and high energy consumption to be eliminated before 2027, which further accelerates the equipment renewal wave of the global brick-making industry.

For new brick plant investors, choosing a cost-effective and future-proof clay brick extruding machine is the key to avoiding elimination and seizing market dividends. Many novice factory owners only focus on the initial purchase price and ignore core performance indicators such as extrusion stability, equipment durability, and energy consumption, resulting in low finished brick qualification rates, frequent equipment failures, and soaring long-term operating costs. Combined with 2026 industry new standards and market demand changes, we summarize the three most critical purchasing criteria for vacuum clay brick-making machine:

1. Stable High-pressure Extrusion Adaptable to New Material Standards

Modern high-end construction projects have extremely strict requirements for brick density, flatness, and crack resistance. Ordinary low-pressure extruders cannot meet the production needs of high-quality split-face terracotta bricks and exterior wall decorative bricks. Our full-series vacuum extruders maintain a constant 3.0MPa stable extrusion pressure, which can fully compact clay, shale, and mixed raw materials, effectively solving common industry pain points such as loose brick blanks, surface cracks, and hollow interiors. This high-pressure molding technology perfectly adapts to the high-standard brick supply requirements of current commercial buildings, residential villas, and landscape paving projects.

2. Hard-tooth-surface Reducer Core for Long-term Low Maintenance Cost

Equipment durability is the core factor that determines the profit margin of brick factories in the era of industry upgrading. Most low-end paver brick production machine on the market adopt soft-tooth reducers, which are severely worn under long-term high-load clay extrusion work. They need to replace gears and accessories every 2-3 years, resulting in frequent factory shutdowns and huge maintenance costs. In contrast, our brick extruder is equipped with a premium hard-tooth-surface reducer with high-frequency quenching treatment on the gear surface, which resists strong friction of viscous raw materials. The overall service life of the equipment exceeds 20 years, helping manufacturers effectively reduce post-investment operating costs and comply with the continuous production requirements of modern automated production lines.

3. Multi-model Matching for Graduated Capacity Layout

2026 industry trends show that small-scale scattered brick factories are gradually being eliminated, and medium and large-scale standardized automated production lines have become the mainstream of the market. We provide 5 mainstream specifications of vacuum brick extruder to meet the layout needs of different investment scales:

- Small workshop type (4-8t/h output): JR40/35 model, suitable for small family factories and regional small-batch brick supply projects

- Medium standard type (6-15t/h output): JR40/40 & JR45/40 models, the mainstream choice for most upgraded brick factories, adapting to most urban construction and infrastructure supporting brick orders

- Large industrial type (10-20t/h output): JR45/45 model, dedicated to large-scale fully automatic brick plants, supporting long-term uninterrupted industrial production

In the current industry reshuffle period, investing in high-efficiency, energy-saving, and durable brick-making equipment is no longer an optional upgrade but a necessary condition for surviving and profiting in the global brick market. Excellent fired brick equipment can not only improve finished brick quality to meet high-end market demand but also reduce energy consumption and carbon emissions, helping factories pass international carbon certification and expand overseas high-value order channels.

Why Do Tunnel Kilns Have Large-Area Overburning and Severe Brick Sticking?

In modern automated brick and tile production lines, tunnel kiln firing quality is the core index that determines finished brick qualification rate and overall production profit. Large-area overburning defects and severe green brick sticking are typical frequent faults in tunnel kiln mass production. These quality issues not only ruin brick and tile finished quality but also cause unnecessary material waste and unexpected production shutdown losses. This article comprehensively analyzes all potential root causes of tunnel kiln overburning and brick adhesion, and compares defect mechanisms with ring kilns, helping brick manufacturers carry out fast and accuratekiln fault troubleshooting and production optimization.

Excessive internal combustion heat of green bricks is the most fundamental material-induced cause of firing overburning and adhesion. In standard brick and tile manufacturing processes, green blanks are formulated with a certain proportion of internal fuel to support self-firing. Once the internal combustible content is too high, the extra heat released during high-temperature sintering will far exceed the standard process temperature required for brick forming. In the relatively closed high-temperature operating environment of tunnel kilns, redundant heat cannot be dissipated timely, resulting in over-fired brick surfaces and tight mutual adhesion between adjacent green bricks.

Imperfect ventilation system configuration is the key environmental factor triggering large-scale overburning faults. A qualified tunnel kiln air supply and exhaust system relies on precise alignment between brick stack ventilation channels and kiln wall exhaust ducts to form balanced hot air circulation and stable temperature fields. Any duct misalignment or blocked ventilation passages will sharply reduce the kiln’s overall heat dissipation capacity. Accumulated internal combustion heat erupts violently in the high-temperature firing zone, creating localized ultra-high temperature zones that lead to widespread brick overburning and severe sticking problems.

Unreasonable reserved gaps between brick stacks and the kiln main body is a easily neglected structural defect in daily kiln operation. The brick and tile industry has a clear standard: the gap between brick stacks, kiln walls and kiln roofs must not exceed 80mm. Excessively large gaps directly cause air short-circuiting in the kiln: more than 80% of circulating and cooling air flows rapidly through the peripheral gaps, while the inner area of brick stacks stays in a static air state. Insufficient preheating makes green bricks unable to adapt to the high-temperature sintering environment, and instant intense internal combustion after entering the high-temperature zone finally causes overburning and blank adhesion.

Non-standard brick stacking technology directly hinders internal heat exchange and air convection inside brick stacks. Excessively dense stacking layouts and insufficient reserved ventilation gaps between adjacent stacks completely block vertical and horizontal air flow. Heat generated by blank internal combustion is fully trapped inside the dense brick stack, forming local ultra-high temperature areas. Under such conditions, brick surfaces precipitate liquid phases in advance, which is the direct cause of persistent sticking and large-area overburning phenomena.

Irregular manual operation and unreasonable process adjustment are critical human factors leading to recurrent firing defects. To pursue higher daily output or simply stabilize flame position, many operators adopt improper gate control strategies, including overusing near gates, refusing to lift far gates properly, and allowing excessive fan suction to press down gate height. These wrong operations disrupt the standard firing temperature curve, shorten the reasonable heat preservation period of green bricks, and trigger premature liquid phase sintering, forming irreversible overburning and brick adhesion faults.

Mismatched kiln body structural parameters are the essential equipment-level cause of poor firing quality. If the tunnel kiln is manufactured with an overly short body, the effective length of the preheating zone and high-temperature roasting zone will be insufficient. Green bricks cannot complete gradual, gradient temperature rise preheating, and directly rush into the high-temperature firing zone. The sharp temperature difference leads to instantaneous intense combustion of internal fuel, causing overall temperature field imbalance and large-area firing overburning and sticking defects.

Compared with tunnel kilns, traditional ring kilns have more concentrated and single causes of overburning and sticking. The four core fault factors include excessive internal combustion heat of green blanks, insufficient preheating zone design length, unreasonable high near-gate operation habits, and inadequate overall kiln exhaust suction, which cover almost all common ring kiln firing adhesion problems.

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