What Is Moisture Content?

Moisture, Chinese vocabulary, shu fèn, means water contained in an object.

[shu fèn]

Moisture

(1) Water contained in objects.

Plenty of water; fresh

Also known as "

• First method direct drying method

Analysis steps

5.1 Solid sample: Take a flat aluminum or glass flat weighing bottle and place it in a drying box at 101 105 . The bottle cap is slanted on the side of the bottle, heat for 1.0 h, remove the cap, and cool in a desiccator. 0.5 h, weigh, and repeat drying until the mass difference between the two before and after does not exceed 2 mg, which is constant weight. Quickly grind the uniformly mixed sample to less than 2 mm in size, and cut the sample that is not easy to grind as much as possible. Weigh 2 g to 10 g sample (accurate to 0.0001 g), put it into this weighing bottle, and test The thickness of the sample should not exceed 5 mm. If it is a loose sample and the thickness does not exceed 10 mm, cover it and place it in a dry box at 101 105 after precision weighing. After h, cover and remove, place in a desiccator for 0.5 h and weigh. Then put it in a drying box at 101 105 for about 1 hour, take it out, put it in a desiccator to cool for 0.5 h, and then weigh it. And repeat the above operation until the difference between the two before and after the mass does not exceed 2 mg, that is constant weight.

Note: In the final calculation of the two constant weight values, the last weighing value is taken.

5.2 Semi-solid or liquid sample: Take a clean weighing bottle, add 10 g of sea sand and a small glass rod, put it in a drying box at 101 105 , dry it for 1.0 h, and take it out into a desiccator. After cooling for 0.5 h, weigh and repeat drying to constant weight. Then weigh 5 g to 10 g of the sample (accurate to 0.0001 g), place it in an evaporating dish, stir with a small glass rod and put it on a boiling water bath to dry it. After drying in a drying box at 105 for 4 hours, cover and take it out, put it in a desiccator to cool for 0.5 h, and weigh. In the following, operate according to 5.1 from "then drying in a drying box at 101 ~ 105 for about 1 hour ..." according to law.

The moisture content in the sample was calculated according to formula (1).

In the formula:

X the moisture content in the sample, the unit is grams per hundred grams (g / 100g);

m1 Mass of weighing bottle (with sea sand and glass rod) and sample, the unit is gram (g);

m2 The weight of the weighing bottle (with sea sand and glass rod) and the sample after drying, the unit is gram (g);

m3 The weight of the weighing bottle (with sea sand and glass rod), the unit is gram (g).

When the moisture content is 1 g / 100 g, the calculation result retains three significant figures; when the moisture content is less than 1 g / 100 g, the result retains two significant figures. ^[2]