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The pycnometer method is the only method that can be used with powders or granules.

Performing Density Determination using the Pycnometer Method

(in Accordance with German and European Standard DIN EN 725-7)

The true density of the powder is the ratio of the mass of the powder to its true volume, and the true volume does not include the closed voids present inside the powder particles.

Therefore, it is necessary to use a non-porous material to determine the true density of the powder.

Depending on the medium to be measured, the main methods for determining the true density of the powder can be classified into a gas volume method and a liquid immersion method.

In the immersion method, the powder is immersed in an immersion liquid on the surface of the easily wettable granules, and the volume of the liquid to be excluded is measured.

This method must be vacuum degassed to completely eliminate air bubbles.

The vacuum degassing operation may be carried out by heating (boiling) and decompression, or both.

The immersion method mainly has a pycnometer method and a suspension method.

Among them, the pycnometer method has the advantages of simple instrument, convenient operation and reliable results, and has become one of the methods for measuring true density which are currently used more.

Therefore, the following is an experimental description of the immersion method:

The pycnometer method determines the true density of the powder based on the "Archimedean principle".

The powder to be tested is immersed in an immersion liquid which is wetted and dissolved, and vacuum is removed, and the powder sample is taken out from a container of a known capacity to discharge a liquid of a known density, and the true density of the measured powder can be calculated.

The true density ρ is calculated as:

ρt= Wa ×ρo/（Wb-Ww） g/cm3

Where:

Wa、the weight of the dry cement powder---- g

Wb、dry cement powder + pycnometer filled with liquid weight---- g

Ww、The weight of the liquid filled with the pycnometer after the cement powder is immersed in the liquid----g

ρo、the density of the immersion liquid at the measured temperature---- (g/cm3)

ρt、the true density of the powder----(g/cm3)