There is no simple method that can accurately replace professional testing, but preliminary screening can be performed through appearance, density, and X-ray. The purity of magnesium oxide must be definitively confirmed by chemical analysis from a third-party CNAS-accredited institution. The following methods are only used to rule out obvious abnormalities.
1. Visual Inspection (Rapid Initial Screening)
Acceptable Characteristics: The powder is white, fine, and free of lumps, and contains no gray-black or yellowish-brown particles;
Abnormal Signs: Dark color, lumps, or foreign matter may indicate the presence of impurities such as Fe₂O₃ or CaO, or that the powder has absorbed moisture.
Trace impurities (such as Cl⁻, SO₄²⁻) cannot be determined by color alone and still require further testing.
2. Filling Density Test (Indirect Judgment)
Procedure: Measure the mass of powder per unit volume using a standard graduated cylinder;
Acceptable Range: 2.8–3.2 g/cm³;
Abnormalities: Low density may be due to high impurity content, coarse particles, or high porosity caused by moisture absorption.
This method can help determine the uniformity of raw materials, but it cannot directly reflect chemical purity.
3. X-ray Inspection (Structural Screening)
Key Inspection Points: Whether there are voids, off-center cores, or uneven density in the filled tube;
Resolution Requirement: ≥5μm;
Judgment Basis: Uneven structure may indicate uneven mixing of raw materials or impurities affecting flowability.
This can be used as a non-destructive auxiliary method in the production process, but it still needs to be combined with chemical testing.
Key Items Required for Testing
Table Test Item Acceptance Standard Test Method
MgO Content ≥95% Acid-base titration method
Active Magnesium Oxide ≥60% Hydration method
Hydrochloric Acid Insoluble Matter ≤0.5% Filtration and weighing method
Cl⁻, SO₄²⁻ ≤0.02% / ≤0.1% Titration or turbidimetric method
