Seeking Breakthrough Amid Structural Overcapacity: Multi-Variety Alumina Achieves High-End Scale Production, Gains Certification from Leading Battery Separator and Sapphire Manufacturers

Against a backdrop of structural overcapacity in bulk metallurgical alumina alongside high import dependence for high-end materials, China's alumina industry is making a strategic pivot towards refinement and functionalization. Recently, multi-variety alumina, represented by high-purity ultrafine alumina powder and alumina for high-transparency plates, has achieved stable mass production at the ten-thousand-ton scale. Its key specifications have reached international advanced levels, and it has successfully entered the supply chains of leading domestic lithium battery separator coating and consumer electronics sapphire glass substrate manufacturers. This marks a profound transformation of China's alumina industry from reliance on "tonnage" to pursuing "grade" and "value-added."

1. Technical Milestone: Deep Impurity Removal and Precise Morphology Control Processes
The core of this industrialization lies in a transformative extension of the traditional Bayer process, achieving ultimate control over purity and microstructure:

1. Deep Chemical Impurity Removal and Seeding Decomposition Technology

• Patented Process: Introduces a multi-stage coupled purification technology after the Bayer hydrate stage to selectively remove key impurities such as Na, Ca, Si, and Fe. By optimizing seeding decomposition kinetics, the final product achieves an alpha-alumina conversion rate >99% and a stable Na₂O content ≤100 ppm, laying a purity foundation for subsequent high-end applications.

• Narrow Particle Size Distribution Control: Employs specialized calcination and jet milling processes to control the D50 median particle size of high-purity alumina for separator coatings within a narrow range of 0.5μm ± 0.1μm, with a particle size distribution span <0.8. This significantly enhances slurry dispersion stability.

• For high-transparency alumina ceramics used in sapphire crystal growth, a rare earth-based composite sintering aid has been developed. This enables sintering to near-theoretical density (>99.9%) under atmospheric pressure, achieving a linear transmittance >20% in the 400-700nm visible light spectrum, meeting the stringent requirements for optical uniformity in high-quality substrates.

2. Market Application Certification: Entering High-Growth Sectors
The new products have gained validation from key customers in high-value industrial chains:

3. Industry Impact: Reshaping Value Chains and Cost Advantages
The mass production of multi-variety alumina is altering the cost and supply chain structures of relevant downstream industries:

• Accelerated Import Substitution: In the lithium battery separator field, the domestic market share of high-end coating alumina has increased from less than 30% to about 60%, significantly reducing separator production costs and strengthening the overall competitiveness of China's lithium battery industry chain.

• Leap in Technological Value-Add: Compared to bulk metallurgical grade alumina (market price ~¥3,000/ton), high-end separator coating alumina can command prices of ¥20,000-30,000/ton, while ultra-high purity alumina powder for sapphire can exceed ¥100,000/ton, representing a value-add increase of tens of times.

• Collaborative Innovation in the Industry Chain: Alumina producers and downstream customers have shifted from "standard supply" to a "joint R&D" model. For example, prospective joint development projects have been initiated targeting alumina for next-generation solid-state battery electrolytes.

4. Corporate Strategy and Capacity Layout
Leading companies are strategically deploying around "base-ization" and "specialization":

• Integrated Bases: Establishing dedicated production lines in major alumina-producing regions like Shandong and Guangxi, leveraging raw material and energy cost advantages to ensure stable supply and cost competitiveness for high-end powders.

• Specialized Parks: Setting up deep processing and application R&D centers in downstream industry clusters like the Yangtze River Delta and Pearl River Delta to provide customized solutions and rapid technical service.

• Market Launch Program: Offering first-order trial discounts and free application process debugging services for new separator or ceramic customers to accelerate product adoption.

5. Verifiable Data and Industry Standards
All performance claims are supported by clear testing protocols:

• Purity Testing: Elemental content tested via ICP-OES.

• Physical Properties: Particle size distribution follows ISO 13320 laser diffraction; specific surface area measured via BET method.

• Industry Standards: Products benchmark against and meet the highest-grade requirements of industry standards such as 《YS/T 89-2021 Alumina for Batteries》.

The large-scale breakthrough of multi-variety, high-end alumina is a representative case of China's basic raw material industry climbing to high-value-added segments upstream in the industrial chain. It serves not only as a "release valve" to alleviate overcapacity in bulk products but also as a "booster shot" empowering downstream strategic emerging industries (new energy, next-generation IT), signaling that China's alumina industry has entered a new competitive dimension in the global value chain.