ingsm 15 the application of laser granulometer on carbon powder characterization for quality control...
TRANSCRIPT
INGSM 15
The application of laser granulometer on carbon powder characterization for quality control and
optimization of nuclear graphite products
Qian Zheng1, Jing Zhang1, Yuzhen Mao1, Junguo Zhao1, Dai Huang1, Houzheng Wu1,2*
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Background
Laser granolumeter
Test conditions
Outline
Application
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Background
A strict control of particle size and size distribution of powders of carbon power is required
Graphite power Nuclear fuel pellets
high temperature gas-cooled reactorsGraphite
Coke powder
Mixing powder
Ultrafine powder
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Why laser grnulometer
Vibrating screening Airflow screening
Laser granulometer
Grain size measuring means
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Vibrating screening
Advantage: easy to operate and achieve
Disadvantage: a ) Measurement of size distribution is discreteb) Agglomerated particles can’t go through the sieve – suitable for large particulates, rather than fine ones.
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Airflow screening
Airflow screening
Advantage:
The scope, efficiency, precision and repeatability of
airflow screening are better than vibration
Disadvantage:
a) Only one sieving can be used for separation each
time, leading to a complex operation required.
b)The detailed size distribution is hard to be
provided.
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Laser granulometer
Grain size measuring means
Advantage: A small amount of power is enough to have details on size distributionquick and convenience, good repeatability, Cover wide range of particle sizes.
Disadvantage: Risk of error for a lack of representativeness
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Test conditions
Instrument: laser granulometer (S3500), US Microtrac corp.
Samples:
graphite powder,
coke powder,
mixed powder of coke and binder,
ultrafine powder, i.e. D50<5µm)
Surfactant used:
Triton X-100(octyl phenoxy poly ethoxy -US Fisher Scientific)
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Results
Suspension concentration
The affect of suspension concentration on different material
excessive
appropriate
small
√ √
√
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Results (cont.)
Repeatability test with different suspension concentration of mixing power
Repeatability is poor for a sample lack of representativeness
√
√
Best choice Risk on instrument maintenance
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Results (cont.)
using surfactant
Before
After
√
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Results (cont.)
The affect of surfactant on different materials
√
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Results (cont.)
The affect of ultrasonication on different material
√
√ √
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Results (cont.)
Repeatability test results of different materials under optimum disperse conditions
D50:CV-2.03%D50:CV-0.87%
D50:CV-3.21%D50:CV-4.04%
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Application
model
Laser granolometer measurements are used as the fundamental inputs of modelling,
for achieving the best possible particle sizes and size distribution through a
combination of powders with different ones, with models developed via theoretical
prediction.
New particle population =A+B+ C+…
WE chose A,B,C three types of powder having different size distribution, and had
the : : in different ratios, such as 3:1:3 , 2:1:2 , 3:1:2
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Application (cont.) The comparison between theoretical prediction and experimental measurement
Theoretical result
Test result
Test result
Theoretical result
Test result
Theoretical result
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Application (cont.)
Relation between CS and SSA
CS: Specific surface area that was calculated by size distribution data
with a hypothesis that particles are all spherical solid.
SSA: Specific surface area measured with BET based on the N2
adsorption
We chose different raw materials, 1 and 2, which is milled with same
equipment but different conditions to get five powders with different
size distribution.
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Application
Relation between CS and SSA
CS SSASSA/CS
R
I
0.323 4.7 14.6
0.97
0.3 4.7 15.7
0.331 4.67 14.1
0.338 5.08 15.0
0.563 7.7 13.7
II
0.262 1.23 4.7
0.99
0.273 1.3 4.8
0.279 1.3 4.7
0.346 1.68 4.9
0.356 1.68 4.7
SSA=k*CS
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Application
Relation between CS and SSA
CS SSA
5min 4h
k
Need more experiments to build the model
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Summary
To achieve better dispersion suitable for laser ganulometer, appropriate suspension concentration, surfactant, and ultrasonication are necessary
It is approved possible and controllable to achieve a powder with expected particle population through combining powders with different particle population, based on a theoretical model.
If the powder production technology is relatively stable and consistent, it is possible to establish relationship between normalized specific surface area measured with laser granulometer and that with BET based on the N2 adsorption. It will offer foundation on estimating
the SSA by laser granulometer.
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Thank you for your attention!