What is the compressibleness of the powder?

Powder is a collection of many small particles of matter, which has a more specific physical characteristic:
has a liquid-like fluid flow.
has a gas-like compressibleness.
has solid anti-deformation ability,
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powders are everywhere in people's production and life. The process of preparation, processing, transportation, packaging and application of powder is affected by the materiality of powder. In the past, "Monday Ask" introduced the fluidity of powder, this article with you to explore what powder compressibleness.
compressibleness of the powder
when the powder is compressed in a loose build-up state, the volume of the powder build-up is reduced, i.e. the gap between particles is reduced. Since the parting is usually in a slightly pressurized state in the unit of operation of the powder, the compressibleness of the powder is usually indicated by the loose stacking state and the tight stacking state of the powder.
the theory of compression molding and the compression characteristics of various materials are of great significance for the prescription screening and process selection and filling of powders to compress powder drugs into tablets.
compression force and volume
powder compression process accompanied by the reduction of volume, solid particles are compressed into a tight combination, but its volume change is more complex.
of compressibleness is
1. Compressible
when the powder is compressed in the loose stacking state, its accumulation volume will be reduced. The gap between particles is also reduced accordingly. The compressibleness of the powder is related to its accumulation state, and the compressibleness (C) is used to indicate the compression degree of the powder, and its size reflects the condensation and soft state of the powder. The definition is as follows:
C is (ρbt-ρb)/ρbt×100%
C is compressible, ρbt is vibration density, ρb is the loosest density.
less than 20% of the liquidity is better, the compressibleness increases when the liquidity is reduced.
2. The compressibleness of the powder Hausner ratio
powder can be expressed as the ratio of the solid density of the powder vibration to the maximum loosest density, also known as the powder Hausner ratio formula (HR). HR is often used to characterties the compressibility and fluidity of powders. The formula is:HR ρbt/ρb
ρbt is vibration density, ρb is the loosest density.
size of the powder particles affects the density at which the powder accumulates. The experimental results show that the particle size increases and the accumulation density difference becomes smaller. As a result, the HR value of the coarser particles is smaller (<1.2), the HR value of the fine particles is larger (>1.4), and the very fine particles have a higher HR value (>2).
the ratio of compressibility of the powder to HR is:
The effects of compression
C-100 (1-1/HR
the compressibility of the powder affects the powder's reunification and mobility. Generally speaking, the higher the compressibleness of the powder, the worse the fluidity of the powder, the stronger the reunion. The relationship is as follows: