As a core raw material for abrasives and refractories，white fused alumina has a quality that directly affects processing efficiency and product performance。This article builds a systematic selection framework from three dimensions：composition analysis，physical properties，and application compatibility，helping users accurately identify high-quality products。

I. Composition analysis：a dual test of alumina purity and impurity control

Grading standards for alumina content

According to the GB/T 2478-2008 standard，industrial-grade white fused alumina must have an alumina content of ≥99.0%，while specialized applications（such as semiconductor wafer lapping）require ≥99.6%。Taking WA-grade white fused alumina produced by a company in Henan as an example，its alumina content reaches 99.8%，and the impurity Na₂O content is below 0.2%，significantly improving the material’s resistance to acid and alkali corrosion。

Impurity control technology

The magnetic separation iron-removal process can reduce the iron content from 0.15% to below 0.03%，meeting the zero iron contamination requirements for aerospace titanium alloy processing。Acid washing treatment can remove alkaline impurities such as silicon oxide and calcium oxide，further improving product purity。

II. Physical properties：synergistic optimization of particle size distribution and bulk density

Precise control of particle size distribution

Tested with a laser particle size analyzer，high-quality white fused alumina must meet the range requirements of D10≥90μm，D50=180±10μm，and D90≤280μm。For F220-grade white fused alumina produced by a certain company，its particle size concentration reaches 95%，effectively reducing surface scratches caused by coarse particles。

Correlation between bulk density and true density

Bulk density reflects the compactness of particle packing，and high-quality white fused alumina must have a bulk density of ≥1.85g/cm³。True density（3.95-4.0g/cm³）reflects the inherent densification of the material，and together they determine the wear resistance and service life of grinding wheels。

III. Application compatibility：precise matching from processing requirements to environmental conditions

Parameter matching for grinding scenarios

In high-speed steel grinding，F120-F220 grade white fused alumina is selected，and its Mohs hardness of 9.0 and self-sharpening property can achieve a surface roughness of Ra0.2μm。For ceramic substrate polishing，W7-grade micro powder（particle size 14-20μm）combined with magnetorheological technology can improve surface flatness to λ/10（λ=632.8nm）。

Chemical stability in refractory material scenarios

In a high-temperature environment of 1700℃，the linear expansion coefficient of high-quality white fused alumina is only（7-9）×10⁻⁶/K，significantly lower than that of fused brown alumina（8-10×10⁻⁶/K）。After a steel mill used white fused alumina-based castables，the ladle service life increased from 80 heats to 240 heats，and the cost per ton of steel decreased by 35%。

Environmental protection and safety performance

Low free-silica white fused alumina（SiO₂ content＜0.1%）can avoid the risk of silicosis，and its lower explosive limit（LEL）for dust reaches 120g/m³，far higher than that of ordinary abrasives。In stainless steel polishing，HACCP-certified white fused alumina products can ensure heavy metal leaching＜0.5ppm。

IV. Quality verification：closed-loop verification from laboratory testing to on-site trials

Laboratory testing system

An XRF fluorescence spectrometer is used to test alumina content，with an error range of ±0.1%；particle size distribution is verified by both the sieving method and the sedimentation method；a thermogravimetric analyzer（TGA）is used to test the mass loss rate at 1600℃（high-quality product＜0.3%）。

On-site trial evaluation

In casting，a sand mold hardness tester（HBW）is used to test molding sand strength，and high-quality white fused alumina can increase molding sand strength by 20%；in sandblasting operations，processing consistency is evaluated by comparing data from a surface roughness tester（Ra value）and a profilometer（Rz value）。

Selecting high-quality white fused alumina requires building a three-dimensional "composition-physical-application" evaluation system。For fields such as semiconductor processing，ultra-pure grade products with alumina content ≥99.6% and particle size concentration ≥95% should be preferred；while in heavy machinery grinding，purity requirements can be appropriately relaxed，with emphasis placed on the balance between bulk density and self-sharpening property。By establishing a supplier whitelist and implementing batch traceability management，quality risks can be further reduced，achieving a match between material performance and processing benefits。