What s going on with crystalline water in gypsum

Gypsum is formed in anhydrous gypsum, semi-aqueous gypsum and dihydrate gypsum through different calcination temperatures, and the moisture of gypsum should be tested in the whole gypsum molding process, and the content of gypsum crystal water and gypsum adhesion water is controlled by CS-001 gypsum crystal water detector at the same time;

It is the water molecule in which the gypsum (gypsum directly mined from minerals) is symbiotic with the gypsum crystals. When the gypsum is calcined to mature the gypsum, the crystallized water is gone.

Plaster is a crystalline rotten mixture containing gypsum dihydrate, hemihydrate gypsum, and anhydrous gypsum. Raw gypsum will appear when the building gypsum is underfired during the frying process, or anhydrous gypsum will appear when the fire is large and the frying time is too long, which will affect the condensation time of the gypsum and affect the normal use of the product. Sometimes the plaster is damp due to being left for too long, which will also affect its normal use.

By measuring the content of crystal water, the quality of plaster can be judged. Generally, the content of qualified plaster crystal water is between the bonds. If the crystal water content of the plaster is much lower than this standard value, it means that the plaster is overburned, and if the crystal water content of the plaster is much higher than this standard value, it means that the phenthic gypsum is underfired or damp.

Gypsum comes in the form of anhydrous gypsum, hemihydrous gypsum and dihydrate gypsum.

The composition of gypsum is calcium sulfate, which combines with water molecules. At this time, the water answer is crystal water.

For example, the gypsum powder used to make the model is calcium sulfate hemihydrate, calcium sulfate hemihydrate reacts when exposed to water to form calcium sulfate dihydrate, calcium sulfate dihydrate is stable in hand and has sufficient strength. The common plaster image or line is calcium sulfate dihydrate.

Summary. How much is the crystalline water of gypsum? Hello, the crystal water content of gypsum refers to the water content in the crystalline chemical formula CaSO4·2H2O in gypsum, which is commonly called "gypsum dihydrate".

Its crystal water content is about 21 grams per 100 grams of gypsum dihydrate. When gypsum dihydrate is heated or a certain amount of water is added, it will lose part or all of the crystalline water and transform into semi-aqueous gypsum (caso4·1 2h2o) or anhydrous gypsum (caso4), accompanied by changes such as volume reduction and hardness increase.

How much is the crystalline water of gypsum? Hello, the crystal water content of gypsum refers to the water content in the crystalline chemical formula CaSO4·2H2O in gypsum, which is usually called "dihydrate early or gypsum". Its crystalline pure water content is about 21 grams of crystal water per 100 grams of gypsum dihydrate.

When gypsum dihydrate is heated or a certain amount of water is added, it will lose part or all of the crystalline water and transform into semi-aqueous gypsum (caso4·1 2h2o) or anhydrous gypsum (caso4), accompanied by changes such as volume reduction and hardness increase.

How much water is attached to plaster, etc.?

The content of attached water such as gypsum refers to the amount of water adsorbed or bound in materials such as gypsum. The exact content varies from material to material and generally needs to be determined by experimental determination. Taking gypsum as an example, the water content rate of celery is generally between 5% and 6%, that is, every 100 grams of gypsum contains about 5 6 grams of attached water.

This adhesion is usually caused by a certain amount of water adsorbed on the surface of the gypsum particles, or by the addition of an appropriate amount of water during the preparation process. For other materials such as concrete, wood, etc., there is a similar situation, and the content of the attached water trace Shouchang also needs to be determined according to the specific situation.

Crystalline water and adhesion water of desulfurized gypsum.

Desulfurized gypsum is an industrial waste that is mainly composed of gypsum and calcium oxide. Among them, crystal water and attached water are two different forms of water. Crystalline water refers to the water that is stored in the slag in the form of crystals in gypsum, also known as crystalline bound water.

During the preparation process, the gypsum reacts with a certain amount of water to form hardened gypsum, and some water is released in the process. This released water combines with hardened gypsum to form crystalline water. Therefore, for desulfurization gypsum containing crystal water, it contains a certain proportion of inorganic salts and crystal water.

Adherent water refers to the free or dissolved water adsorbed or absorbed on the surface of gypsum particles. These free or dissolved moisture attached to the surface of the particles can usually be removed by heating, etc.

Hello, I am happy to serve you and give you the following answers: The difference between gypsum crystal and crystal: gypsum crystal is a synthetic material, which is made of a mixture of gypsum and gypsum powder, which has strong hardness and wear resistance, and can be used to make various decorations, such as jewelry, jewelry, etc.

Crystal is a natural mineral with high hardness and wear resistance, which can be used to make various ornaments, such as jewelry, jewelry, etc. Reasons for the problem:1

Due to the different properties of gypsum crystal and crystal, it is easy to have a weak bond during the production process, which leads to poor quality of decorations. 2.Due to the different hardness of gypsum crystal and crystal, it is easy to break during the production process, resulting in poor quality of decorations.

Workaround and practice steps:1In the production process, high-quality gypsum crystals and crystal cloths should be used to ensure the quality of the decorations.

2.During the manufacturing process, high-quality adhesives should be used to ensure a strong bond between the gypsum crystal and the crystal. 3.

During the production process, high-quality tools should be used to ensure that the breakage rate of gypsum crystals and crystals is low. 4.In the production process, attention should be paid to the matching of gypsum crystal sheds and crystals to ensure the quality of decorations.

Teaching: During the teaching process, the properties of gypsum crystals and crystals should be explained in detail, as well as how to use gypsum crystals and crystals correctly to make ornaments to ensure the quality of the ornaments. Personal Tips:

When making ornaments, it should be noted:

The gypsum formula is: The formula is 40 + 32 + 64 + 2 18 = 172, where the molecular weight of H2O is 18, so the theoretical moisture content of CaSO4·2H2O = 18 2 172 100% =

The molecular formula of raw gypsum is calcium sulfate dihydrate. Contains two crystalline waters.

Determination of crystal water content.

1. Weigh 100g of gypsum (through a square hole sieve with a pore size) and mix it well.

2. Place the sample in a closed container (temperature 20 2, humidity 65% 5%), lay a uniform layer with a maximum thickness of 10mm, and let it stand for 18 24h.

3. Heat in a 40 4 oven for 1h, put it in a dryer to cool to room temperature, and weigh.

4. Repeatedly heat, cool and weigh until constant weight.

5. Weigh 2g (balance indexing value.

The specimen is placed in a weighing flask with a grinding plug that has been dried to a constant weight.

6. Heat in the 230 5 oven for 45min (open the lid during the heating process).

7. Take out the sample with crucible pliers, cover the grinding plug (not too tight), and put it in the dryer to cool for 15m.

8. Cover the grinding plug tightly and weigh it.

9. Place the open cover of the sample in the oven and heat it for 30m under the condition of 230 5.

10. Take it out, and place the cover grinding plug in the dryer to cool for 15m.

11. Repeated heating, cooling, and weighing until constant weight, and the difference between the two judgment results should not be greater than.

12. Calculate the percentage content of crystal water.

m: Mass of the sample before heating; m1:

Quality after heating.