How to Test the Activity of Magnesium Oxide After Rework

The standard procedure of "hydration method determination" must be used in a laboratory with CNAS certification to examine the activity of magnesium oxide following rework. The gold standard in the industry, this method precisely determines the active magnesium oxide concentration by measuring the quantity of magnesium hydroxide generated when magnesium oxide reacts with water.

 

1. Acceptance criteria and testing standards

Standard Basis for Item Acceptance

Content of Active Magnesium Oxide

≥60%

"HG/T 3928-2012"

Method of Testing

Determining the Hydration Method

The National Standard Designated Method

A dense insulating structure can only be formed during sintering with a composition of at least 60%.

 

2. Method of Determining Hydration

Preparing Samples

Choose at least three representative powder samples from the rework batch.

To avoid moisture absorption influencing the results, samples must be packed and preserved.

Reaction of Isothermal Hydration

For two hours, the sample is agitated with distilled water at a steady temperature of 40±1°C.

Magnesium hydroxide is created when water and magnesium oxide (MgO) combine.

Following the reaction, a normal hydrochloric acid solution is used to titrate the unreacted MgO.

The amount of acid consumed is backcalculated to determine the mass of reacting active MgO.

Calculation of the Result

The mass of reactive magnesium oxide divided by the total mass of the sample equals the active magnesium oxide content (%) × 100. To prevent interference from contaminants, this procedure must be carried out by experts in a clean laboratory.

 

3. Suggested Testing Facilities (CNAS Accredited)

Samples must be delivered to approved third-party entities in order to guaranty authoritative and traceable data:

Zhongxi Testing (supports more than 22 tests, nationwide sample delivery)

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)

As the legal foundation for quality release, the report must display the CMA/CNAS mark.

 

4. Safety Measures and Typical Error Causes

Points of Risk

Control Suggestions

Hygroscopicity of the Sample

Before testing, store in a tight container and avoid exposure to high humidity levels.

Unclean Water

Make use of water with a resistivity of at least 18.2 MΩ·cm.
Variations in Temperature

Utilise a water bath with a consistent temperature of ±0.5°C.

Inadequate Reaction Time

Make sure you have a two-hour reaction time.

The evaluation of sintering capability may be impacted by any departure in any phase, which could result in poorer outcomes.