In modern industrial production, equipment and facilities in high temperature environment are facing extremely severe challenges, and clay refractory brick, as a key refractory material, provides reliable protection for these high temperature equipment. Especially in coke oven, an important industrial equipment, clay refractory bricks play an indispensable role. This paper will introduce the characteristics, performance index, quality control, packaging and transportation and related services of clay refractory bricks for coke ovens in detail to help readers fully understand this important material.

I. Product introduction

Clay refractory brick for coke oven is a kind of high performance refractory specially designed for coke oven. It is mainly used in the main parts of coke oven, such as furnace wall, roof and other key parts such as coal inlet. These refractory bricks can withstand various physical and chemical effects in high temperature environment, ensuring the normal operation and service life of coke oven.

II. Features and Advantages

Clay refractory bricks for coke ovens have the following remarkable characteristics and advantages:

(1) Low impurity content

Low impurity content is an important characteristic of clay refractory bricks. The existence of impurities may trigger a chemical reaction at high temperature, leading to the instability of brick structure. The clay refractory brick with low impurity can effectively reduce this risk and improve the durability and reliability of the brick body.

(2) high dimensional accuracy

In the process of coke oven construction and maintenance, the dimensional accuracy of refractory bricks is very important. Refractory bricks with high dimensional accuracy can ensure the compactness and uniformity of masonry, reduce heat loss and improve the thermal efficiency of coke oven. Clay refractory bricks for coke ovens are strictly controlled to ensure that the size of each brick is within the standard range.

(3) Low heat storage capacity

Low heat storage capacity means that refractory bricks can dissipate heat quickly in high temperature environment and reduce the accumulation of heat in the brick body. This is of great significance to the temperature control and energy saving of coke oven. Refractory bricks with low heat storage capacity can transfer heat in a short time, avoid local overheating and prolong the service life of coke oven.

(4) High compressive strength

Coke oven will bear great pressure during operation, so refractory bricks need to have sufficient compressive strength. Clay refractory bricks for coke oven have high compressive strength, can withstand high temperature and high pressure environment for a long time, and ensure the structural stability of coke oven.

(5) High temperature resistance

High temperature resistance is one of the core indexes of refractory bricks. Clay refractory bricks for coke oven can maintain stable physical and chemical properties at high temperature, and will not be deformed or damaged due to temperature rise. This enables the coke oven to run stably at high temperature for a long time.

(6) High mechanical strength

In addition to compressive strength, refractory bricks also need high mechanical strength to resist various mechanical impacts and wear. The high mechanical strength of clay refractory brick for coke oven enables it to maintain good performance in complex industrial environment and reduce the frequency of maintenance and replacement caused by mechanical damage.

III. Physical and chemical indicators

Physical and chemical indexes of clay refractory bricks for coke oven are important basis to measure their properties. The following is a detailed index comparison of two common specifications (JN-40 and JN-42):

Refractory: Refractory refers to the resistance of refractories to melting at high temperature. The refractories of JN-40 and JN-42 are both above 1730℃, and the average refractoriness of JN-42 is as high as 1750℃, which can meet the requirements of coke oven in high temperature environment.

Apparent porosity: Apparent porosity refers to the percentage of the volume of visible pores in refractories to the total volume. The standard of apparent porosity of JN-40 is ≤24%, with an average of 22.3%. The apparent porosity standard of JN-42 is also ≤24%, with an average of 21.8%. Lower apparent porosity is helpful to reduce heat loss and improve the thermal insulation performance of refractory bricks.

Bulk density: Bulk density is an index to measure the unit volume quality of refractories. The average bulk density of JN-42 is 2.2g/cm³, while the bulk density of JN-40 is not clearly marked. Higher bulk density usually means that refractory bricks have better compressive strength and wear resistance.

Compressive strength at room temperature: compressive strength at room temperature refers to the ability of refractories to resist pressure at room temperature. The normal temperature compressive strength of JN-40 is ≥24.5MPa, with an average of 42.9MPa；; The room temperature compressive strength of JN-42 is ≥24.5MPa, with an average of 44.3MPa. High compressive strength can ensure that refractory bricks will not be damaged by external forces during use.

Load softening temperature: Load softening temperature refers to the temperature at which refractories begin to deform under a certain load. The load softening temperatures of JN-40 and JN-42 are both ≥1350℃, and the average value of JN-42 is 1410℃. The higher load softening temperature indicates that the refractory brick has better stability under high temperature and load conditions.

Re-burning line change rate: Re-burning line change rate refers to the change rate of refractory length after firing at high temperature. The change rate of reheat line of JN-40 and JN-42 is ≤0.5% at 1350℃×2, with the average value of JN-40 being 0.11% and JN-42 being 0.12%. The low change rate of reburning line shows that the firebrick has good dimensional stability after high temperature firing and is not easy to deform.

Thermal shock resistance times: The thermal shock resistance times refer to the times that the refractory can maintain its integrity after repeated rapid heating and cooling processes. The thermal shock resistance of JN-42 is ≥10 times (water cooling at 1100℃), while the thermal shock resistance of JN-40 is not clearly marked. High thermal shock resistance times show that refractory bricks can withstand frequent temperature changes and adapt to the start-stop and temperature fluctuation of coke oven during production.

ALO content: ALO (alumina) content is one of the important factors affecting the performance of refractory bricks. The Al₂O₃ content of JN-40 is ≥40%, with an average of 42.9%. The Al₂O₃ content of JN-42 is ≥42%, with an average of 43.5%. Higher Al₂O₃ content can improve the refractoriness, chemical corrosion resistance and mechanical strength of refractory bricks.

IV. Quality Control

Quality is the lifeline of products, and a strict quality control system has been established in the production process of clay refractory bricks for coke ovens. Professional quality inspectors will sample each batch of products to ensure that the product quality meets the standards. Unqualified products will be banned from leaving the factory to safeguard the reputation of enterprises and the interests of users.

(1) Professional quality inspection

Quality inspection includes chemical analysis and physical performance test. Chemical analysis can accurately determine the chemical composition of refractory bricks to ensure that they meet the design requirements; The physical performance test includes the detection of refractoriness, apparent porosity, bulk density, compressive strength and other indicators to comprehensively evaluate the performance of refractory bricks.

(2) Appearance inspection

Appearance inspection is one of the important links of quality control. Inspectors will strictly check the dimensional tolerance, deformation, cracks, corner defects, melting holes and color of refractory bricks. Any appearance defect that does not meet the standard may lead to performance problems of refractory bricks in use, so it must be strictly controlled.

V. Summary

Clay refractory brick for coke oven is a kind of refractory material with excellent performance. Its low impurity content, high dimensional accuracy, low heat storage capacity, high compressive strength, high temperature resistance and high mechanical strength make it widely used in coke oven field. Strict quality control system, reasonable packaging and transportation mode and perfect after-sales service provide users with reliable protection. Zibo Zhuoyue Refractory Co., Ltd. relies on many years of production experience and advanced production technology to provide high-quality refractory products for users all over the world and help the stable development of high-temperature industry.

In the future industrial development, with the continuous progress of technology and the increasingly strict requirements of environmental protection, clay refractory bricks for coke ovens will also face new challenges and opportunities. Through continuous technological innovation and product upgrading, refractory bricks will make greater contributions to the efficient operation of coke ovens and energy conservation and emission reduction.