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Measurement of Certified Cementwith Dry Jet Dispersion
Technology
Control devices such as particle size analyzers have to be
precise and reliable.In order to verify the accuracy of these
devices, the cement industry has established certified cement. It
allows:
- A regular check of the accuracy of the instrument (validation
control)
- The standardization of measurements between different
manufacturing sites for national or international companies.
The cement industry improves the performance of its products
every day. This continuous adaptation of production plants to
technical, ecological and so on requirements makes it necessary for
regular monitoring during cement manufacturing.
Some samples are taken in every step of the process and routed
to a control laboratory. A fast and precise analysis device allows
the duplication of controls in order to be compliant to the major
standards. Different types of cement have to follow strict
guidelines in terms of composition, particle size...
These characteristics affect the mechanical properties, setting
time and so on of the different kinds of cement. The manufacturing
process controls properties and helps in the reduction of
production cost. About 1% of the worldwide energy production is
consumed by the cement industry, mostly during the grinding
step.
Particle size analysis helps cement manufacturers optimize the
grinding process and therefore reduce their cost. Particle size
analyzers are a good way to control the process and reduce
costs.
Labs such as the National Society of the Littoral (SNL) in
France produce some cement. An amount of this cement is taken and
homogenized. Then the samples are packaged in airtight containers
and are sent to different laboratories (figure 1).
Introduction
Why Certified Cement ?
Figure 1 : Vial of Reference Cement with Certificate
002
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Measures of Reference Cement #8 from SNL were performed on a
CILAS PSA with DJD Technology.
The SOP for Dry mode was :- P = 220 mbars- Vibratory Level :
1/9- Obscuration : 10%
Results
Results obtained show that the cement is measured correctly in
dry mode using Dry Jet Dispersion (DJD) technology.
Results
0.76%0.98%Max Value
0.74%0.79%Mean Value
0.70%0.60%Min value
CILAS PSANISTResidue at 45mSNL Expected values
34.34
11.52
0.99
Min
41.3945.33D90%
14.0815.2D50%
1.512.29D10%
CILAS PSAMax
The French Technical Association of the Industry of the
Hydraulic Binder (ATILH) is one of worldwide companies which
certifies cement for particle size analysis.
It arranges an interlaboratory test campaign each year. The
participants are mostly French or European laboratories from
various stages of cement production and consumption :
- Cement manufacturers,- Raw material producers,- Cement users,-
Research and control centers for building materials.
These tests improve the reliability of the cement test methods,
compare the methods and verify the measurement
reproducibility.CILAS application laboratory takes part in this
campaign.
Certified Cement, such as that produced by NIST, is available
for sale. This cement is used for sieve control. NIST gives the
residue value at 45m for its certified cement. Performing cement
measurements allows us to observe a good correlation between the
sieve values and the results from a CILAS particle size
analyzer.
How to obtain Certified Cement Data?
SNL Cements
Measurement of Reference Cement using DJD Technology
NIST Cement
Cement is measured with the two most popular techniques for size
measurement in the cement industry: sieve and wet mode laser
particle size analysis. The cement measurement tests are numerous
and sometimes involve several operators and/or several experiment
maps.
Analysis of the results consists in doing statistical treatment
using working methods and in producing a table with all the cement
characteristics.The measures are centralized by ATILH and are
treated using classical statistical analysis: Student test,
Laplace-Gauss distribution, Cochran test, and Grubbs test.
Certified cement is commercially available in vials provided
with a measurement certificate containing a table listing the
expected size distribution.
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CILAS new dry measurement technology shows excellent
reproducibility. The pressure needed to disperse powders is low
(less than 1 bar) and prevents the possible erosion of particles.
Cohesive powders like cement are perfectly dispersed.
Excellent correlation between wet and dry modes is obtained
because of the innovative calibration method of the two dispersion
modes according to ISO 13320 (figure 2).
Figure 2 : Reproducibility of 3 measurement of SNL Reference
Cements
The innovative Dry Jet Dispersion Technology offers the
following advantages for the Cement industry:
- Fine dispersion of cement particles at low pressure (less than
1bar)- Excellent reproducibility on a cohesive powder such as
cement- Ideal correlation to recognized cement standards (ATILH,
NIST,)
Analysis on results of Certified Cement measurement
Conclusion
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DJD technology is available on CILAS instruments in 3 different
measurement ranges. All instruments are available with the DJD
system alone or in combination with the Wet Iso Dispersion system
(WID system).
Range
Modes of calculation Fraunhofer, Mie
0.3 - 500 m 0.1 - 500 m 0.1 - 2500 m
Ways of Dispersion Venturi Venturi - Free Fall
Accuracy < 3 % on NIST traceable CRM (1)
Repeatability < 1 % on NIST traceable CRM (1)Performances
compliant with ISO 13320 norm
Amount of sample 5 g minimumAcquisition time 5 s
minimumCompressed Air (2) 0 - 4 +/- 0.01 bars
Number of lasers
Wavelength
Power
Length/width/height
Weight
1 2635 and 830 nm
54 kg (119 lbs)
1830 nm
830 mm / 560 mm 480 mm (33 in / 22 in / 19 in)50 kg (110
lbs)
3635 and 830 nm
60 kg (132 lbs)
110/240 V - 50/60 Hz - < 100 VA)
Number of classes 70 100 100
(1): measures of diameter by weight made on certified reference
materials, traceable to NIST standards (2): Air compressor and
vacuum cleaner systems available in option
930 1064 1180
Technical specifications
Principle of
measurementLaser Diffraction Laser Diffraction & CCD
camera
