HA500 Reactive Alumina Powder for Low-Water Demand Refractory Castables
HUAO HA500 Reactive Alumina Micro-Powder is an ultra-fine, high-purity alpha-alumina specifically developed for advanced refractories and technical ceramics. Characterized by ultra-low soda and impurity levels, a high BET surface area (typical 7.5 m²/g), and a controlled singlet particle size distribution with a median diameter of D50 = 0.5 μm, HA500 delivers exceptional sintering reactivity.
By filling sub-micron interstitial voids within refractory aggregates, HA500 optimizes particle packing density, drastically reduces water demand, and enhances matrix fluidity. In critical applications such as steel ladle linings, blast furnace iron runners, and self-flowing castables, HA500 accelerates rapid sintering to improve hot mechanical strength, thermal shock endurance, and resistance to molten slag erosion.
Technical Specifications
| Features |
Unit |
Typical |
Min |
Max |
| Na₂O |
% |
0.08 |
-- |
0.10 |
| Fe₂O₃ |
% |
0.02 |
-- |
0.03 |
| MgO |
% |
0.07 |
0.05 |
0.10 |
| SiO₂ |
% |
0.03 |
-- |
0.07 |
| CaO |
% |
0.02 |
-- |
0.03 |
| Surface Area (BET) |
m²/g |
7.5 |
6.5 |
8.5 |
| D50 Cilas (Median Particle Size) |
μm |
0.5 |
0.3 |
0.6 |
| D90 Cilas |
μm |
2.0 |
-- |
3.0 |
| Particle Distribution |
-- |
Singlet |
-- |
-- |
Note: Grain size distribution can be customized according to specific customer process requirements.
Key Features
The ultra-fine singlet particle distribution (D50 = 0.5 μm) fits into particle voids, significantly reducing the mixing water required for refractory castables while improving slurry flowability.
Featuring a high BET surface area (typical 7.5 m²/g), HA500 promotes lower-temperature densification and solid-state sintering, creating a robust, tightly bonded ceramic matrix.
Strictly controlled sodium oxide (Na₂O ≤ 0.10%) and iron oxide (Fe₂O₃ ≤ 0.03%) prevent low-melting phase formation, preserving high-temperature refractoriness under load.
Enhances cold crushing strength (CCS), flexural strength, and thermal shock resistance, creating a dense barrier against molten slag penetration.
Applications
High-Performance Refractory Castables
Reactive Alumina can increase matrix density and slag resistance under severe exposure to molten steel, enhance thermal shock stability and mechanical resistance to molten iron wear. It is also very suitable for porous purge plugs, seat blocks, and shields that require a dense microstructure. It can also optimize the rheological and flowability of amorphous refractory material devices.
Technical Ceramics & Specialty Industries
Reactive Alumina can be used for high-density ceramic parts that require precise particle filling and low porosity. It can also be added to alumina structures to achieve high hardness and strict mechanical tolerances.
Why Choose HUAO
Our factory operates strictly in accordance with ISO 9001, ISO 14001, and ISO 45001 management standards. With over 10 years of international B2B export experience, HUAO acts as the on-site eye for customers, conducting batch size (Cilas) and chemical composition testing to ensure absolute batch stability. The infrastructure that can be directly manufactured ensures stable supply capacity, direct cost advantages, and thoughtful technical after-sales service.
Packaging & Customization
HUAO HA500 is supplied in standard 25 kg moisture-proof multi-layer woven bags or heavy-duty 1000 kg / 1250 kg bulk jumbo bags (Ton Bags) equipped with polyethylene inner liners. Customized particle distributions and private-label export packaging can be arranged to meet specific client requirements.
FAQ
Q1: What makes HA500 different from standard calcined alumina micro-powders?
A1: HA500 is a reactive grade with higher reactivity (BET 7.5 m²/g) and a tighter singlet particle size distribution (D50 = 0.5 μm). This allows it to act as a reactive sintering aid, whereas calcined powder primarily acts as an inert micro-filler.
Q2: How does HA500 help reduce water consumption in refractory castables?
A2: Its optimized sub-micron singlet distribution fills micro-voids between larger corundum or tabular alumina grains, releasing trapped capillary water and enabling high slurry fluidity with reduced water addition.
Q3: What is the significance of low soda content (Na₂O ≤ 0.10%) in HA500?
A3: Low soda prevents the formation of weak, low-melting glass phases (such as beta-alumina) at elevated temperatures, maintaining high hot strength and refractoriness under thermal loading.
Q4: Can HUAO adjust the particle size specification for custom recipes?
A4: Yes, HUAO provides tailored particle size distributions to match unique refractory castable or technical ceramic process specifications.
We also provide other high-purity alumina products. If you would like to learn more about Tabular Alumina or White Fused Alumina, please contact our technical sales team.
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