Publish Time: 2026-05-21 Origin: 本文由AI 辅助生成，圣原耐材产品部审核发布
In the new dry cement production process, the rotary kiln is the core thermal equipment, and the transition zone of the rotary kiln in the cement industry is located between the firing zone and the decomposition zone, with a temperature range of approximately 1100°C-1300°C. This area not only bears high-temperature thermal stress, but also faces chemical erosion from volatile components such as alkali, sulfur, and chlorine, as well as mechanical stress caused by cylinder deformation. With the popularization of collaborative disposal of waste (such as domestic waste, hazardous waste, tires, etc.) in the cement industry, the working conditions in the transition zone have become increasingly harsh, alkali-sulfur corrosion has intensified, and the life of traditional refractory materials has been significantly shortened. Therefore, the selection and matching of refractory materials in the transition zone of rotary kilns in the cement industry has become a key link affecting the kiln operation rate and overall cost.
Customers found in actual production that refractory materials used in the transition zone of rotary kilns in the cement industry generally face three core pain points :
First, alkali-sulfur corrosion causes structural spalling. After the co-processing of waste, the concentration of alkali metal oxides (K₂O, Na₂O) and SO₃ in the kiln gas increased significantly. They penetrated into the lining of the rotary kiln transition zone in the cement industry to form low-melting-point phases such as potassium feldspar and albite, causing frequent peeling of the hot surface of the bricks. In serious cases, it can lead to 'red kiln' accidents.
2. Compound damage caused by thermal shock and mechanical stress. The temperature in the transition zone fluctuates frequently (up to 30℃-50℃ per hour), and it is located in the 'suspended section' of the kiln barrel, with large ovality changes. It is difficult for ordinary refractory bricks to balance thermal shock resistance and compressive strength, and they are prone to circumferential cracks and even bricks falling off.
Third, the kiln skin hanging ability is weak and the kiln skin is unstable. The transition zone of the rotary kiln in the cement industry is different from the firing zone in that the amount of liquid phase is smaller, and the kiln skin of traditional materials is slow and unstable. After the kiln skin repeatedly fell off, the brick body was directly exposed to hot air flow, which accelerated chemical erosion and wear, leading to local premature failure and forcing the kiln to be shut down for repairs.
These three pain points overlap each other, making the transition zone of the rotary kiln in the cement industry the "short board" in the life of the entire rotary kiln, seriously restricting the continuous operation cycle of the production line.
In response to the above pain points, Shengyuan Refractories launched a special magnesia-chrome brick solution for the transition zone of rotary kilns in the cement industry , providing full-stack support around material formula optimization, structural design and construction support.
In terms of product selection, we recommend the use of high-purity direct bonded magnesia chrome bricks . This magnesia-chromium brick is made of high-purity fused magnesia and chromium concentrate as raw materials. It is formed by high pressure and sintered at high temperature (≥1700℃). It has the following customized characteristics:
l Optimize the Cr₂O₃ content (10%-12%) to avoid excessive embrittlement while ensuring corrosion resistance;
lIntroduce microporous matrix design to reduce the penetration depth of alkali salts;
lAdd composite mineralizer to increase the direct bonding rate of magnesia-chromium bricks (≥85%) and enhance thermal shock resistance.
In terms of technical support , we provide three supporting services:
1. Diagnosis of working conditions in the kiln: Based on the customer's material composition, fuel type and co-processing plan, the transition zone temperature field and alkali-sulfur partial pressure are simulated to accurately match the magnesia-chromium brick grade.
2. Optimization of the masonry process: the 'staggered joint masonry + accurate control of brick-locking steel plates' solution is recommended to avoid circumferential stress concentration; compressible cushions are supplemented in areas with large deformations to absorb changes in the ovality of the cylinder.
3. Guidance on drying kiln and hanging kiln skin: Provide temperature rise curve suggestions, and guide the coordination of air, coal, and materials in the initial stage of production to accelerate the formation of a dense and stable transition zone kiln skin and protect the magnesia-chromium brick body.
Through this special magnesia-chromium brick solution, customers do not need to frequently change brick types of different materials, nor do they need to make large-scale modifications to the kiln structure, which can significantly extend the service life of the transition zone of the rotary kiln in the cement industry.
Take a 5000t/d cement production line in North China as an example. This line co-processes municipal sludge and waste tires. The original ordinary magnesia-alumina spinel bricks have an average lifespan of only 5-6 months in the transition zone of the rotary kiln in the cement industry, and the risk of red kiln is high. After using Shengyuan"s special magnesia-chrome brick solution, the following effects were achieved:
l Extended service life: The service life of the transition zone of rotary kilns in the cement industry has been increased to 12-14 months, which is more than 130% longer than before, and one less kiln shutdown for maintenance.
l Improved thermal shock stability: After 50 simulated thermal cycles (1100°C ⇌ air cooling), the residual strength retention rate of magnesia-chrome bricks reaches 82%, while the original bricks only maintain 61%.
l The depth of alkali erosion is reduced: After 9 months of use, sampling analysis showed that the thickness of the alkali penetration layer of magnesia chrome bricks is ≤8mm, which is more than 50% lower than the industry average level (15-20mm).
l Comprehensive cost reduction: the cost of refractory materials per ton of clinker dropped from 2.8 yuan to 1.7 yuan, a decrease of approximately 39%; at the same time, the loss of output (about 2,400 tons of clinker) caused by two unplanned kiln shutdowns was avoided.
In addition, the special magnesia-chromium bricks for the transition zone of rotary kilns in the cement industry have been recognized by the customer"s production department in terms of stability of the kiln skin and resistance to mechanical spalling, and have been promoted and used in many production lines of the group.
The working conditions of Shengyuan Refractories has been deeply involved in the high-temperature industry for more than ten years, focusing on the transition zone of rotary kilns in the cement industry are continuing to upgrade with the co-processing process, and traditional refractory materials are no longer able to match them. providing highly reliable magnesia-chrome brick customized solutions for the transition zone of rotary kilns in the cement industry . If you are facing problems such as short service life of the transition zone, frequent red kiln occurrences, and high costs, please contact us for one-to-one working condition diagnosis and product selection suggestions. You can also apply for magnesia-chrome brick samples and trial masonry plans . We provide full technical tracking services.