1 Material Definition and Preparation Process

Tabular Alumina (TA), also known as tabular corundum, is a high-purity α-Al₂O₃ ceramic material produced via high-temperature sintering. The core process involves using high-purity alumina pellets as raw material and rapidly sintering them at temperatures between 1900–1950°C (as opposed to arc melting), promoting the growth of plate-like α-Al₂O₃ crystals. This results in numerous fine closed pores within the crystal structure, with open porosity approaching zero.

In international materials classification, the standard name for tabular alumina is "Tabular Alumina." Due to its limited Mohs hardness, it is rarely used in abrasive applications and instead serves as one of the key raw materials in advanced refractory products.

2 Key Physicochemical Properties  

The performance parameters of tabular alumina must meet strict industrial standards. Key specifications are as follows (based on GB/T 2684-2007 "Refractories—Terminology" and ASTM C714-15 "Standard Test Method for Chemical Analysis of Alumina Refractories"):

- Main component: Al₂O₃ ≥ 99.2% (mass fraction)  

- Impurity content: Na₂O ≤ 0.30% (low-sodium grades can be controlled to Na₂O ≤ 0.15%)  

- Bulk density: 3.52–3.56 g/cm³ (measured by Archimedes displacement method)  

- Apparent porosity: 2.5–4% (dominated by closed pores, tested via vacuum impregnation)  

- Melting point: 2050°C (determined by differential thermal analysis and high-temperature hot stage observation)  

- Particle size distribution: Granules (5–10 mm, 3–5 mm, 1–3 mm, 0.5–1 mm, 0–0.2 mm); fine powders (-200 mesh, -325 mesh). Packaging options include bulk bags or 25 kg bags.

3 Microstructure and Performance Advantages  

The superior properties of tabular alumina stem from its unique plate-like crystalline structure and internal closed pore system, offering the following advantages:

1. Excellent thermal shock resistance: Internal closed pores effectively buffer thermal stress (thermal expansion coefficient α ≈ 8.0×10⁻⁶/°C), resulting in significantly higher residual strength retention under rapid heating and cooling cycles compared to conventional fused white alumina.

2. Strong slag resistance and erosion resistance: The closed pore structure blocks penetration pathways for molten steel and slag, reducing refractory dissolution rates and extending service life.

3. High-temperature dimensional stability: Re-fired shrinkage < 0.2% (after 3 hours at 1600°C); excellent high-temperature creep resistance (creep rate < 0.5% under 10 MPa load at 1500°C).

4. High interfacial bonding strength: Rough particle surfaces (surface roughness Ra ≈ 5–10 μm) enhance mechanical interlocking and chemical bonding with refractory matrices (e.g., spinel, carbon-based materials), significantly improving both room-temperature and high-temperature strength in castables and bricks.

Note: The Mohs hardness of tabular alumina ranges from 9.0 to 9.2, lower than that of white fused alumina (9.3–9.5), making it unsuitable for applications requiring high abrasiveness such as grinding or sandblasting.

4 Major Application Areas  

Tabular alumina is primarily used in high-temperature industrial sectors, including:

1. Steel Metallurgy (Core Market)  

Used in ladle castables, alumina-carbon bricks, alumina-magnesia-carbon bricks, magnesia-alumina spinel bricks, slide gates, permeable bricks, ladle refining linings, and precast components. It can partially replace fused white alumina, enhancing the thermal shock resistance and slag resistance of refractory materials.

2. Unshaped Refractories

Used as aggregate in high-end castables, ramming masses, and shotcretes for linings of high-temperature equipment such as steel-making converters, cement rotary kilns, waste incinerators, and petrochemical cracking furnaces.

3. Specialty Kiln-ware and Industrial Ceramics

Applied in high-temperature kiln components (e.g., saggers, push plates), electronic insulation parts, foam ceramic filters, and catalyst supports, leveraging its high purity and chemical inertness.

4. Low-Sodium Tabular Alumina (LITAL-99LS Series)  

With extremely low Na₂O content (≤0.15%), it prevents material bloating and cracking caused by sodium ion emanation, making it ideal for applications sensitive to impurities, such as sintering saggers for lithium batteries and high-purity ceramics.

5 Performance Comparison between Tabular Alumina and Fused White Alumina

| Performance Parameter  | Tabular Alumina  | Fused White Alumina (WFA)         

| Preparation Process | Sintering at 1900–1950°C | Arc melting and cooling at 2200°C |

| Microstructure | Plate-like crystals + abundant closed pores | Equiaxed crystals + open pores + microcracks |

| Thermal shock resistance | Excellent (thermal shock cycles > 50) | Moderate (thermal shock cycles < 30) |

| Slag penetration resistance | Strong (slag penetration depth < 2 mm) | Weak (slag penetration depth > 5 mm) |

| High-temperature dimensional stability | Good (re-fired shrinkage < 0.2%) | Poor (re-fired shrinkage > 0.5%) |

| Mohs hardness | 9.0–9.2 | 9.3–9.5 |

| Main applications | High-end refractory materials | Abrasives, general refractories |

6 Major Brands Worldwide  

6.1 Leading Domestic Brands  

1. Zhejiang Zili: LITAL-99 (standard grade), LITAL-99LS (low-sodium grade, among the top exporters in China);  

2. Shandong Ruishi (Nuodun Ruishi): Refractory-grade tabular alumina (focused on steel metallurgy applications).  

6.2 Overseas Brands  

1. Almatis (Omya): T60/T64 (global technical benchmark for tabular alumina, classic grades);  

2. RHI Magnesita: Specialized high-end ladle refractory grades (technologically derived from Omya).  

Note: Almatis was an early developer of tabular alumina technology; currently, some of its orders are manufactured by domestic factories.

7 Academic English Abstract  

Tabular alumina (TA) is a high-purity sintered α-Al₂O₃ material produced via rapid sintering at 1900–1950°C, characterized by a plate-like crystal structure and intragranular closed pores. With Al₂O₃ content ≥99.2% and low Na₂O levels, TA exhibits excellent thermal shock resistance and slag erosion resistance, and high-temperature volume stability. Its main applications include high-end refractories for steel ladle, monolithic refractories, special kiln furniture, and low-sodium grade for lithium battery saggers. Compared with fused white alumina, TA shows superior performance in thermal stability and slag resistance, making it a key material in high-temperature industrial fields.