Alumina hollow sphere castable is an ultra-lightweight, high-strength refractory material formulated with high-purity alumina hollow spheres, high-alumina fines, high-performance binders, and carefully selected additives.
      It offers high refractoriness, low bulk density, excellent thermal insulation, and outstanding thermal shock resistance.
The material is widely used in energy-efficient high-temperature furnace linings, thermal shock-resistant structures, insulation layers, and critical component repairs.
      It can be used in conjunction with lightweight castables, corundum castables, lightweight corundum bricks, and ceramic fiber modules to create highly efficient, energy-saving furnace lining systems.

      Alumina hollow sphere castables feature high refractoriness under load and excellent strength, making them suitable for service temperatures of 1500–1800°C.
      They are available in several compositions, including alumina, zirconia, mullite, alumina–magnesia, and magnesia–chromium systems, with alumina-based hollow spheres being the most widely used in refractory castables.
      Fly ash cenospheres are another type of hollow sphere, recovered from coal combustion fly ash. They are widely used as a raw material for lightweight bricks and as a functional additive in refractory castable formulations.

      The primary binders include CA-70 or CA-80 cement, binding clay, aluminum phosphate, and aluminum sulfate.Fine industrial alumina or corundum powder forms the refractory matrix, with over 90% passing 0.09 mm (90 μm). Hollow spheres are used up to a maximum size of 5 mm, with either natural or engineered grading.Selected additives are incorporated to enhance performance.
      These castables are widely used in metallurgical, petrochemical, and carbon black kilns, supporting advanced process technologies while improving energy efficiency and operational performance.

Packaging:
The products are packed on export-grade pallets, wrapped with stretch film, and protected with moisture-proof bags.
Standard packaging options include 50 kg per bag or 1 metric ton per jumbo bag.
Reinforced packaging solutions are available for sea freight and long-distance transportation.

As a leading manufacturer of refractory materials and provider of furnace lining engineering services in China, Shandong Haixin is a recognized leader in alumina hollow sphere castables and high-temperature energy-saving materials. Our strengths come not only from our production scale and advanced equipment, but also from more than 30 years of practical engineering experience across industries including metallurgy, petrochemicals, ceramics, environmental protection, and energy.

●Large, modern production facility with reliable and stable supply capacity.

Equipped with an automated production line, the facility produces 100,000 tons of unshaped refractory materials annually. Its full production chain and reliable lead times ensure support for both batch production and customized solutions.

●Equipped with a strict quality control system and state-of-the-art testing equipment.

The technology center is equipped with state-of-the-art instruments, such as a fully automated dilatometer, refractoriness under load tester, flat-plate thermal conductivity meter, thermal shock tester, and high-temperature reheat furnace. Every batch of materials is rigorously tested for physical properties, chemical composition, and temperature resistance.

●Integrated engineering and construction services with materials supply.

      The company holds a Class A professional contracting qualification for waterproofing, anti-corrosion, and thermal insulation projects, as well as a Class B general contracting qualification for metallurgical engineering construction. It also maintains a specialized furnace construction team.
      By integrating materials, design, construction, technical upgrades, and maintenance, we provide comprehensive one-stop solutions.

●Fast, reliable, and professional technical support.

       We offer furnace lining design, material selection, construction guidance, and energy-saving renovation solutions. Our services include 24/7 technical support and a team of experienced engineers to address complex operational challenges.

Q1: What is the operating temperature range of the product?
A: The product has a typical service temperature of 1700–1780℃, placing it among the highest temperature grades of lightweight energy-saving materials.

Q2: What are the differences between it and lightweight castable?
A: Alumina hollow sphere castables offer superior mechanical strength, refractoriness, and thermal shock resistance compared with standard lightweight castables, making them ideal for critical components that require both strength and thermal insulation.

Q3: Is the material suitable for use on the furnace roof?
A: Yes, it is suitable for furnace roof applications. Its low density helps reduce the lining weight, while providing excellent thermal shock resistance and structural stability, which significantly prolongs the service life of the furnace roof.

Q4: Is vibration required during construction?
A: Depending on the product type, most alumina hollow sphere castables are highly self-flowing and can be poured or cast without the need for intensive vibration.

Q5: Are alumina hollow sphere castables suitable for long-term continuous operation?
A: Yes. Composed of high-purity alumina hollow spheres, this material maintains structural stability at high temperatures and resists pulverization or collapse, making it ideal for long-term continuous operation. In high-temperature furnaces under continuous production, it demonstrates significantly better performance stability than standard lightweight castables.

Q6: Is the hollow sphere prone to breakage during construction?
A: No. It is designed for safe handling during construction. Its dense corundum outer shell provides high mechanical strength. When following recommended construction guidelines-such as avoiding excessive vibration and controlling water content-the hollow spheres remain intact, ensuring the material achieves its intended performance.

Q7: Does it require special care?
A: It is similar to conventional refractory castables, but proper care is recommended: allow natural curing after casting, avoid premature forced heating, and follow the furnace heating curve during initial firing. Proper curing enhances both the final strength and long-term service life of the material.

Q8: Is it suitable for repairing old furnace linings?
A: Yes, it is suitable. Alumina hollow sphere castables are lightweight and highly fluid, making them ideal for repairing or partially rebuilding elevated sections of furnace roofs and walls without imposing additional load on the existing structure.

Q9: Can the formula be customized according to the furnace type?
A: Yes. We can customize formulas based on your furnace structure, maximum temperature, heating profile, and operating environment, including adjustments to bulk density, strength, and workability for optimal performance.

Q10: Do you support OEM/ODM cooperation?
A: Yes, we fully support OEM and ODM cooperation, offering flexible solutions from product customization to end-to-end services, tailored to customer requirements.

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