Transcript Continuous On-Stream XRD New Dimensions to Cement Process

ICCC 2007
Montreal, Canada
Continuous On-line Measurement of
Cement and Clinker Mineralogy for
Quality Control and Optimisation
using X-ray Diffraction
Dr Peter Storer
Principle Scientist,
FCT-ACTech
Raw Materials processed to
Cement Minerals
Continuous
On-Stream XRD
►For Real time Industrial Process Control
►Automatic Mineral Phase Analysis
►In Plant On-Stream Location
►Linked to Plant Control System
►Continuous Analysis
►Data Trending
►Calculated Elemental Analysis
COSMA
Ash Grove Cement Plant –
October 2001
Cement Mill
building
Product
conveyor
tube
Analyser
room
Auger sampling from
mill product
Cement
conveyor at
100-150 tph
Sampling Schematic
1
2
3
4
XRD
Cement Sampling
Schematics –
Multiple lines
COSMA
Three
sample
lines
X-ray tube, sample
stage and detector
Etc.
Automatic Sample
Presentation
Feedscrew
Turntable
Moving sample maximizes number of particles analyzed
Diffraction Pattern –
analysed by Reitveld analysis
120000
Counts
100000
80000
60000
40000
20000
0
600
1100
1600
2100
Two theta
2600
Particle Statistics are Important!
We cannot use Stationary Samples
2500
Intensity (Counts)
2000
1500
1000
500
0
33
34
35
36
37
38
39
Angle Two Theta (degrees)
40
41
42
Diffraction Peaks at Characteristic
Angles,
Only when the alignment is right.
Particle Statistics are
Important!
Rotating Turntable
1500
Intensity (Counts)
1200
900
600
300
0
33
34
35
36
37
38
39
Two Theta Angle (degrees)
40
41
42
Rietveld quantitative
analysis
►Automatic Mineral Phase Analysis
►Parameters optimised for the plant conditions
►Most parameters are fixed for continuous analysis
►Data sets analysed as rolling average every minute
►Accurate analysis obtained
– verified by tests on known samples and shift samples
(eg. Elemental Analysis compared to Lab XRF,
Free lime (CaO) compared to wet chemistry.)
Mineral Analysis –
as it happens!
Monitoring the Cement
• Continuous XRD analysis provides trended
data, showing the composition of the
material throughout the day.
• Trends provide much more information than
spot or composite samples.
• Composite samples are like the average of
the trends.
Trend of gypsum states
after mill stoppage
4
3.5
Weight percent
3
2.5
Hemihydrate
2
Gypsum
1.5
1
0.5
0
20:16
21:16
22:16
Time
23:16
Trend of gypsum states for
constant mill exit temperature
7
Gypsum Dihydrate
Hemihydrate
Mill Feed Gypsum
XRD Derived SO3
Mill Exit Temp.
Percent of material
6
5
110
100
4
90
3
80
2
1
70
0
3:00
Feb
60
24-
11:00
24-Feb
19:00
24-Feb
3:00
Feb
Date/Time
25-
11:00
25-Feb
19:00
25-Feb
Temperature (deg C)
120
Showing the clinker
temperature when hemihydrate
increased
120
Temperature (Deg C)
110
100
90
80
70
60
50
Mill Exit Cement
Temperature
40
Mill Feed Clinker
Temperature
30
3:00
24-Feb
11:00
24-Feb
19:00
24-Feb
3:00
25-Feb
Date/Time
11:00
25-Feb
19:00
25-Feb
Trend of Type change
showing limestone addition
Trend of Loss results on Finished
Cement
3.5
Limit
3
Loss (%)
2.5
2
1.5
1.59
0
10
10
20
30
40
Number of Cases
20
30
1
Number of
Cases
0.5
0
25-Oct-05 14-Dec-05 02-Feb-06 24-Mar-06 13-May-06 02-Jul-06 21-Aug-06
Date
40
50
Examples of Free Lime
variation in clinker
• Free lime is monitored in the clinker to
ensure it is below the maximum limit.
• Excess free lime may indicate under burnt
clinker or excess CaO in the raw meal.
• XRD provides the opportunity to clearly
identify the cause of excess free lime.
60
2.5
50
2.0
40
1.5
30
1.0
20
0.5
10
26 Jan
0.0
28 Jan
27 Jan
Alite
Beliteb
Lime
Percent Free Lime
Percent Alite, Belite
Free Lime Excursion
Underburning…
Free Lime Excursion –
Excess free lime in Kiln Feed
2.5
60
2.0
50
40
1.5
30
1.0
20
0.5
10
0
20 Nov
Alite
21 Nov
Bogue C3S
Beliteb
0.0
22 Nov
Bogue C2S
Lime
Percent Free Lime
Percent Alite, Belite
70
Summary
►Continuous On-Stream XRD Analysis for
material streams – direct on powder or crushed
and ground for coarse samples
►Control based on mineralogical information –
allows timing and direction of control action
►Kiln operation and burner settings
►Cement Mill and Separator operation
►Feed rate control and monitoring
►Direction of Product to Silos
Summary
►Raw Material monitoring/control at the Product
stage allows optimum additive control.
►Limestone, Gypsum
►Quality Monitor
“Like having my best lab guy working 24/7!”
Thank you!
… Questions?
Continuous
Material
Analysis
for cement
production
Continuous
Material
Analysis
for cement
production
Fuel