GRANULATION
Testing with the REVOLUTION
Powder Analyzer
Cohesive
particles in a powder can form larger particles with
material handling. This process can be intentional as in a
granulation process or can be unintentional as in caking
during storage. Either way a powder's quality is
affected by the formation of these larger particles.
The
REVOLUTION Granulation Test
can be used to study powders that exhibit particle size
change during mixing, blending,
transportation, production processing and/or storage.
Initial Powder
Powder after Agglomeration
When
a cohesive powder is placed in a rotating drum, the
continual angular velocity can cause the powder's particles
to join together forming large particles.
The flow properties of this granulated powder will
improve with the formation of larger particles. The
granulation analysis will measure the percentage of change
in the avalanche power from the initial powder state to
the granulated state.Once your powder has granulated, the Revolution
Granulation Test can also test the strength of the
granules by increasing the drum rotation speed to force
high velocity collisions between the granules. These
collisions could cause the newly formed granules to
break up. The granulation software compares the results
of the powder's properties after granulation and after
the increase in velocity to see if the powder remained in
a granular state.
Appropriate powders
for the REVOLUTION
Granulation test include: food
powders, cosmetics, pharmaceuticals, and other powders
with granulation potential.
The
REVOLUTION Granulation Test has five process steps:initial
analysis, agglomeration, agglomeration analysis,
de-agglomeration, and de-agglomeration analysis. These
steps are discussed below.
Initial Step
The initial step will indicate the powder's initial
product characteristics by measuring the statistical
analysis described below. These initial
parameters as seen in Figure Awill be used
as a comparison to the agglomeration and
de-agglomeration analysis steps. The software can measure
the powder's ability to granulate during storage by performing the
initial granulation analysis, storing the powder for a
specified amount of time and continuing the agglomeration
and de-agglomeration steps at a future date.
Initial Process
Agglomeration Step
The
agglomeration step can be performed within the REVOLUTION
Powder Analyzer or in the manufacturing process.
Within the instrument, the powder is rotated at a fixed
velocity for a specified amount of time to allow the particles
to granulate. The rotation speed
and time of rotation of the agglomeration process
are set based on the process parameters. In
the manufacturing process, a powder sample is
taken after the granulation process or material
handling. The new sample is loaded into the test
drum.
Agglomeration Step
Agglomeration
Analysis
The agglomeration analysis indicates if your powder
granulated or clumped in the agglomeration step, whether
within the instrument or in your manufacturing process.
The analysis is completed by determining the percentage
of change in the statistical analysis between the
initial stage and the agglomeration stage.
Agglomeration Analysis
In Figure A, the analysis shows a reduction in
the powder's avalanche power and time during the
agglomeration stage. This change in power and time
indicates that clumps are being formed during the
agglomeration step. The formulation of granules allow
the powder to avalanche more frequently and flow more
freely. As a result of this analysis, the conclusion is
made that this powder is granulating in the
agglomeration process step.
Figure
A-
Cumulative Power Spectrum - Avalanche
Time vs. Power - Initial
Analysis (RED) Agglomeration
Analysis (BLUE)
De-Agglomeration Step
The
de-agglomeration step can be performed within REVOLUTION
Powder Analyzer or in the manufacturing process. On the instrument,
the powder is rotated at a high fixed velocity for
a set time to cause particle
collisions. The rotation speed
and time of rotation of the de-agglomeration
process are set based on the process parameters.
In
the manufacturing process, a new powder sample is
taken after de-agglomeration process or material
handling. The new
sample is loaded into the test drum.
De-Agglomeration Process
De-Agglomeration Analysis
The
de-agglomeration analysis will indicate if the
clumps (or granules) formed during the
agglomeration step break up with an increased
rotation speed.
The
analysis is completed by determining the
percentage of change in the statistical parameters
from the agglomeration analysis to the
de-agglomeration analysis.
De-Agglomeration Analysis
In Figure B,
the analysis shows a slight increase in the powder's
avalanche power and time. Based on this analysis,
the conclusion is made that most of the granules formed
during the agglomeration process have not broken up
into smaller particles with the increased rotation
speed in the de-agglomeration stage.
Figure
B - Cumulative Power Spectrum -
Avalanche Time vs. Power - Agglomeration
Analysis (BLUE) De-Agglomeration
Analysis (GREEN)
In
addition, a comparison is made between the results
of the de-agglomeration stage to the initial stage
to see if the powder returns to its initial
powder's characteristics. In Figure C, the analysis shows
the difference in the avalanche power and time between
the powder's initial analysis,
agglomeration analysis and the
de-agglomeration analysis. Therefore, the
conclusion is made that the powder did not return to its initial powder characteristics.
Figure
C - Cumulative Power Spectrum -
Avalanche Time vs. Power - Initial
Analysis (RED) Agglomeration
Analysis (BLUE) De-Agglomeration
Analysis (GREEN)
In Figures
D and E, the graphical analysis shows two
different powders: one powder that exhibits
granular behavior and one power that does not.
Figure
D -
Cumulative Power Spectrum - Avalanche
Time vs. Power - Granulation
Figure
E -
Cumulative Power Spectrum -Avalanche
Time vs. Power - No Granulation
Once
the granulation test has been completed, the
software will provide the user with the
following statistical analysis for all three
analysis steps: initial, agglomeration and
de-agglomeration.
Please doubleclick on any of the parameters for a
brief measurement description.