How to Improve the Purity of Reworked Magnesium Oxide

Using high-purity raw materials (≥99.9%), sintering under nitrogen protection during the entire process, and having it tested and confirmed by a CNAS-certified organisation are the keys to increasing the purity of reworked magnesium oxide. The ultimate purity will be directly impacted by contamination or process failure at any point.

 

1. Strict Purity Control of Raw Materials (Source Guaranty)

Use high-purity magnesium oxide powder, which must be at least 99.9% pure and include very few important contaminants.

Fe2O3 ≤ 0.05%

CaO < 0.2%

Cl⁻ < 0.02%

SO₄²⁻ ≤ 0.1%

Suggested Vendors:

99.95% high-purity magnesium oxide is supplied by Liaoning Jiashun Technology.

Dashiqiao Meier Magnesium Products (complies with HG/T 3928-2012)

To avoid mixing low-purity or damp powders, batch information must be scanned and traced before raw materials are brought into the warehouse.

 

2. Improve Process Control (Rework Process Contamination Prevention Measures)

Control Points for Steps

Environmental Control: To avoid dust contamination and moisture absorption, work in a cleanroom with RH ≤ 30%.

Equipment Cleaning: Before each use, use high-purity nitrogen to clean the filling and sintering equipment.

Protective Atmosphere: Throughout the sintering process, maintain a high-purity nitrogen atmosphere (≥99.99%) with an oxygen content of less than 100 parts per million.

Powder Transfer: To prevent contamination from airborne moisture and particle matter, operating in an open atmosphere is strictly forbidden.

To stop oxidation and carbonisation reactions, nitrogen protection is essential; real-time oxygen content monitoring is required.

 

3. Third-Party CNAS Testing and Verification (Result Confirmation): To guaranty data impartiality and traceability, samples must be transferred to a third-party organisation recognised by CNAS for authoritative testing following rework.

Suggested Testing Facilities:

Zhongxi Testing (supports more than 22 impurity tests, national sample submission)

Wuhan Kehai Inspection Co., Ltd. (quick report generation, localised service)

Wuhan Branch of Guangfen Testing & Certification Co., Ltd. (with an emphasis on high-purity material analysis)

Essential Test Items:

Content of MgO ≥95%

≥60% of active magnesium oxide

Insoluble substance in hydrochloric acid ≤0.5%

As the legal foundation for quality release, test reports with a loss on ignition of less than 5% must contain the CMA/CNAS mark.

 

4. Create a File for Full-Process Traceability

Every batch of workpieces that are returned will have a distinct coded file that is connected to:

batch of raw materials

Temperature curve for sintering

Record of the atmosphere

Test findings

By achieving closed-loop management of the complete lifecycle-from raw materials to completed goods-this promotes continuous improvement and problem traceability.