K23 Insulating Firebrick

K23 insulating firebrick is a grade of mullite insulating brick. Its good features makes it to be used in furnace equipment to help improve the thermal efficiency of the equipment. As a manufacturer, Kerui provides standard bricks and customized bricks in various sizes to more than 1,000 customers globally.

Free Sample:
Available

Document:
Certificates Supporting

Performance Test:
Support

Shipment:
7-35 working days

Made in China

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Delivery of Kerui K23 Insulating Fire Bricks

Applications of Kerui K23 Insulating Bricks

Basic Parameters of K23 Insulating Firebrick

K23 insulation bricks is also called JM23 bricks, B5 bricks. Please see the parameters.

Item/Grade	KR-23
Type	A	B	C	D
Al₂O₃, %	≥42	≥42	≥45	≥48
Fe₂O₃, %	≤1.2	≤1.2	≤1.0	≤1.0
Bulk Density, g/cm³	0.55	0.6	0.8	1.00
Reheating Linear Change, %	≤-0.5	≤-0.55	≤-0.4	≤-0.3
Temperature*12h	1230℃	1260℃	1300℃	1300℃
Cold Crushing Strength, MPa	≥1.2	≥1.5	≥2.3	≥3
Thermal Conductivity 350℃, W/(m·K)	0.17	0.19	0.24	0.31

Shapes of K23 Soft Fire Brick

The appropriate brick shape improves construction efficiency, furnace thermal efficiency, and the service life of the furnace.

For common insulating firebrick shapes, Kerui offers straight bricks 230*114*65mm/9″*4.5″*2.5″, arch bricks, wedge bricks, tapered brick, end brick, and so on.
For custom-shaped bricks, Kerui can manufacture them according to the customer’s provided drawings and sizes.

Free Sample to Customers for Testing

When many customers purchase Kerui products for the first time, they often worry whether they are really suitable for their high-temperature kiln applications. In order to dispel their concerns, Kerui provide samples for customers to test and verify. 95% of customers fully recognize the high quality of Kerui products after receiving and trying them, and believe that they fully meet their needs, so they choose to continue to place orders and cooperate.

Quality Control of Kerui Insulating Fire Bricks K23

Raw Material Selection And Pre-Treatment

Strictly screen high-purity mullite, alumina and other raw materials to ensure stable chemical composition and low impurity content;

Optimize the particle structure through the awakening process, evenly distribute the particle grading, effectively reduce the porosity of the product, and improve the density and thermal stability.

Intelligent Batching And Molding Control

Use a fully automatic batching system to accurately control the proportion of each raw material to ensure batch consistency;

Use efficient extrusion molding equipment to control the compaction degree and brick structure to ensure uniform brick size and reliable strength.

High-Temperature Firing Process

Equipped with two 168-meter large natural gas tunnel kilns, constant temperature firing and multi-stage temperature control;

Ensure that the product is fully sintered at high temperature, significantly improving thermal shock stability and anti-stripping performance.

Post-Processing And Dimensional Guarantee

Use professional equipment for cutting and fine grinding to ensure that the edges and corners of the bricks are neat and the dimensional tolerances meet international standards;
Especially suitable for furnace parts with complex structures or high precision requirements.

Features of K23 Insulating Bricks

Lightweight Design

With low bulk density, K23 bricks significantly reduce the overall load on kiln structures and furnace linings, making installation easier and enhancing energy efficiency.

Excellent High-Temperature Resistance

Manufactured with high-purity mullite, these insulation bricks maintain structural integrity and thermal performance even under prolonged exposure to temperatures up to 1350–1400°C.

Superior Thermal Insulation

The porous structure ensures low thermal conductivity, effectively reducing heat loss and helping maintain stable internal temperatures — ideal for energy-saving applications.

Outstanding Thermal Stability

K23 firebricks exhibit excellent resistance to rapid temperature changes (thermal shock), minimizing the risk of cracking or spalling during start-up and shut-down cycles.

Low Thermal Conductivity

Delivers exceptional insulation performance while maintaining high temperature resistance, contributing to both fuel savings and worker safety.

Corrosion Resistance

Resistant to chemical attack from molten metals, slags, and other aggressive environments, making them suitable for non-ferrous metallurgy and ceramic kilns.

High Mechanical Strength

Features good compressive and flexural strength, providing durability during transportation, installation, and long-term use in high-stress environments.

Energy-Efficient & Eco-Friendly

The combination of lightweight, low heat storage, and low thermal conductivity helps reduce energy consumption and carbon emissions, supporting sustainable operations.

Package of K23 Insulating Bricks

Package

Ordinary packaging: Standard packaging is wooden pallet packaging. 1 pallet can hold 650-700 standard bricks. And moisture-proof film is added to the upper and lower layers.
Customized packaging: Kerui can also provide customized packaging according to customer requirements.

Full Inspection

Kerui have our own physical and chemical laboratory to regularly test key properties of products such as volume density, compressive strength at room temperature, thermal conductivity, and maximum operating temperature according to standards;

Kerui can provide third-party test reports or product certificates according to customer requirements to ensure compliance with project bidding or export.

Certification

The company has passed ISO 9001 quality management system certification, and the entire production process is traceable;
At the same time, Kerui have obtained ISO 14001 environmental management system certification, focusing on green manufacturing;
Many products have passed CE EU certification, meeting the requirements for export to the EU and other international markets.

Packages of K23 Insulating Bricks at Factory

Application to Industrial Kilns and Furnaces

K23 firebrick is primarily used for the lining, roof, walls, bottom, and flue gas channels of high-temperature equipment.

Glass Kilns: Glass melting furnaces, glass annealing kilns, etc.
Metal Smelting Furnaces: Electric furnaces, heating furnaces, etc.
Industrial Heating Furnaces: Petrochemical heating furnaces, hot air furnaces, etc.
Heat Treatment Furnaces: Annealing furnaces, quenching furnaces, etc. View more details on Linkedin.

Kerui Mullite Insultion Bricks is Trusted by Global Industry Leaders

Kerui Refractory has garnered strong support from customers worldwide. These products have received positive feedback across various regions, reflecting Kerui’s commitment to excellence and customer satisfaction. View more pictures of cases on Pinterest.

Exported to 20+ countries;
70% customer repurchase rate;
1,000+ global customers.

Contact Kerui Refractory

OEM Manufacturer Support

1-on-1 dedicated international sales manager consultation service;

Professional technical support service;

Mold and bricks customization service;

Quick delivery for in-stock items;

On-site construction technical guidance after sales.