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Hydration method to detect magnesium oxide activity

Hebei Messi Biology Co., Ltd. stated that magnesium oxide activity testing is the first step in production and is also a very important link. During the production process, why is it necessary to test the activity of magnesium oxide? There are two main reasons:

High reactive magnesium oxide

Due to differences in ore grade, calcination process, and calcination temperature, the activity content of the calcined magnesium oxide is also different. During the production process, only active magnesium oxide participates in the reaction.

During the storage process of purchased magnesium oxide, affected by storage conditions and environmental humidity, it is easy to react with moisture and carbon dioxide in the air, causing the activity to gradually decrease. The longer the storage time, the more serious the activity loss.

Therefore, to ensure quality, a scientific molar ratio must be carried out based on the actual active content of magnesium oxide, and the formula must be adjusted in a timely manner based on the different active content of magnesium oxide.

There are many methods for the activity of magnesium oxide, such as specific surface method (nitrogen adsorption method, iodine adsorption method), hydration method, conductivity method, citric acid rapid test method, etc. Each of these methods has its own characteristics and scope of application. The focus is here Introducing the method of detecting the activity content of magnesium oxide by hydration method:

Theoretical basis: Only active magnesium oxide reacts with boiling water.

Test equipment: one ten thousandth scale, one oven, and three large beakers.


From the stocked magnesium oxide, take out 100 grams of magnesium oxide samples from different corners and positions (no less than 3 places) and mix them evenly.

Accurately weigh 100g of magnesium oxide from the mixed powder and place it in a dry beaker with constant weight. Add 400g of pure water to make it completely moist.

Put the cup into a drying oven with an adjusted temperature (110°C) and dry it for more than 2 hours. Then adjust the oven to 150°C and dry the sample to a constant weight.

Activity calculation method: Activity content of magnesium oxide = [(W-100)/45]

In the formula, 100 is the weight of the sample before hydration; W is the weight of the sample after hydration; 45 is the conversion factor.
Note: In order to obtain a more accurate value, you can take three 100g magnesium oxide tests, add the final active content values, and then divide by 3.

Issues to note:

During the heating process, avoid the slurry splashing out of the beaker;

Drying time should be as long as possible to ensure complete evaporation of water

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