Transcript Data Mining – Trace Phase Analysis

Data Mining –
Minor Phase Analysis
This tutorial was created from a presentation by Dr. James Kaduk,
Senior Research Associate, INEOS Technologies. The presentation
was given at an ICDD workshop held during the 2008 International
Union of Crystallography Meeting in Osaka, Japan.
The tutorial includes three case histories of industrial problems solved
using the PDF-4+ database and some creative thinking!
The ICDD is grateful to both Dr. Kaduk and INEOS Technologies for
allowing the ICDD to use their data for this tutorial.
Examples of Data Mining
Applications of the Powder Diffraction File
in Industrial Problem Solving
James A. Kaduk
Senior Research Associate
Analytical Sciences Research Services
INEOS Technologies
[email protected]
A Vanadium Phosphate Catalyst for the Oxidation of
Butane
to Maleic Anhydride
[goed80.raw] 21228-95-5 (40,40,0.3) J AK
[goed80.raw] 21228-95-5 (40,40,0.3) J AK
40
Intensity(Counts)
30
20
10
x 10^3
01-089-8338> (VO)2(P2O7) - Vanadium Oxide Phosphate
01-085-2281> (VO)2(P2O7) - Vanadyl Phosphate
01-083-2388> (VO)2(P2O7) - Vanadium Oxide Phosphate
10
20
30
40
50
60
70
80
90
Two-Theta (deg)
From the top, raw data scan, background subtracted scan and
then the phase identification match to phases in the Powder
Diffraction File.
The reference phases are represented as stick figures. The
identification accounts for some of the peaks, but not all peaks
in the pattern.
Locate peaks by interactive
deconvolution, and create
GOED80.PEAK
GOED80.PEAK
7.2107 10
6.3038 15
5.6645
7
4.8107 12
4.4577
1
4.2699
1
4.0957
2
3.9854
4
3.8799 70
3.5823
9
3.2904
1
3.1447 100
3.0760
7
3.0487
4
3.0027 24
2.9864 28
2.6625 14
2.6141
2.4649
2.4415
2.3997
2.3665
2.2550
2.2123
2.0946
2.0780
1.9916
1.9730
1.9377
1.9026
1.8420
1.8293
1.7939
1.7503
1
2
15
2
5
1
1
19
5
1
1
7
2
9
2
1
1
1.7147
1.6488
1.6373
1.6257
1.6007
1.5781
1.5604
1.5232
1.5073
1.4925
1.4757
1.4611
1.4458
1.4210
1.3920
1.3840
1.3525
1
3
5
1
3
10
1
1
2
1
5
5
1
3
1
4
2
Import into SIeve+
Note: SIeve+ is the Search and Identification program, from ICDD,
that is used with PDF-4+ databases. It can utilize a d,I file, such as
the one in this example, or use an experimental data file.
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
00-050-0380> (VO)2P2O7 - Vanadyl Phosphate
20.0
Intensity(Counts)
15.0
10.0
5.0
x10^3
10
20
30
40
50
Two-Theta (deg)
60
70
80
90
Only weak peaks left.
Redo Hanawalt/Fink search,
or use other capabilities…
There is a peak at 7.2107 Å.
Limit our search to phases containing just V, P, O, and H,
and which have a strong peak 7.16 < d < 7.26 Å.
Note: In this real example, supplementary XRF data, taken
at INEOS, limited the number of elements in the specimen.
This information can be used in the search process in
combination with the location of a single d-spacing.
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
20.0
Intensity(Counts)
15.0
10.0
5.0
x10^3
00-050-0380> (VO)2P2O7 - Vanadyl Phosphate
00-047-0967> H4V3P3O16.5·xH2O - Hydrogen Vanadium Phosphate Hydrate
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20
30
40
50
Two-Theta (deg)
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70
80
90
At the time of this analysis,
no structure had been reported for
H4V3P3O16.5(H2O)x.
Search the ICSD for phases containing only
V, P, O, and H.
Found ICSD entry 92847
This subsequently was entered into the
PDF as PDF 01-074-2749!
Boolean search on “just” H,V, P
and O with a strong line at ~7.21Å.
There are still peaks at 3.5823 and 3.0760Å.
Look for phases which have strong peaks
3.55-3.61 and 3.05-3.11 Å.
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
20.0
Intensity(Counts)
15.0
10.0
5.0
x10^3
00-050-0380> (VO)2P2O7 - Vanadyl Phosphate
00-047-0967> H4V3P3O16.5·xH2O - Hydrogen Vanadium Phosphate Hydrate
01-070-0265> V1.08P0.92O5 - Vanadium Phosphorus Oxide
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20
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40
50
Two-Theta (deg)
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70
80
90
Carry out a Rietveld Refinement
Note: In this example, the identified phases were sourced from
the ICSD data. Using the cross references in the PDF database,
the atomic coordinates for a Rietveld refinement can be extracted
from the ICSD database or from the original references.
Alternatively, in PDF-4+ for Rietveld refinement
PDF 04-008-8054 replaces 01-070-0265
PDF 04-011-5579 replaces 00-050-0380
The replacements are identified through PDF’s cross references located in both entries.
Rietveld Refinements
In all the examples, Jim Kaduk follows phase identification with Rietveld
refinement for quantitative analysis. This requires that each entry has a
set of atomic coordinates. There are several ways to get this information
1. Directly from PDF-4+ in the Structure tab,
as shown above. PDF-4+ contains 114,630
data sets with atomic coordinates.
2. From the literature reference
in the Experimental tab.
3. From the cross reference collection code found in the comments tab,
or a cross reference structure found in the Miscellaneous tab.
There is still a peak at 3.985Å.
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
20.0
Intensity(Counts)
15.0
10.0
5.0
x10^3
00-050-0380> (VO)2P2O7 - Vanadyl Phosphate
00-047-0967> H4V3P3O16.5·xH2O - Hydrogen Vanadium Phosphate Hydrate
01-070-0265> V1.08P0.92O5 - Vanadium Phosphorus Oxide
01-084-0048> VO(PO3)2 - Phosphate Vanadium Oxide
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20
30
40
50
Two-Theta (deg)
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70
80
90
Add to the refinement
The quantitative analysis is:
(VO)2P2O7
84.8(1) wt%
H0.6(VO)3(PO4)3(H2O)7
5.9(1) wt%
-VOPO4
5.6(1) wt%
β-VO(PO3)2
3.7(1) wt%
A Deactivated Pd/C
Hydrogenation Catalyst
[nube157.raw] 22247-126D-(UCB-0308-014)/ Fines/ (40,40,0.3) TN
00-046-1043> Palladium - Pd
12.0
Intensity(Counts)
10.0
8.0
6.0
4.0
2.0
x10 3
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Two-Theta (deg)
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90
Automated identification finds the Pd catalyst, but there are
clearly additional phases in the pattern. There is a characteristic
unidentified long line, shown by the arrow, at 4.05Å.
Pd and long line 4.050.02Å
The search finds a number of Pd alloys, most have the formula XPd3.
[nube157.raw] 22247-126D-(UCB-0308-014)/ Fines/ (40,40,0.3) TN
00-046-1043> Palladium - Pd
00-050-1631> Zvyagintsevite - PbPd
12.0
3
Intensity(Counts)
10.0
8.0
6.0
4.0
2.0
x10 3
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Two-Theta (deg)
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The prior search suggested that an XRF analysis would be appropriate (to find X) and Pb
was found in high concentration. PbPd3 was easily identified (above).
The source of Pb in the plant was found and removed, solving the deactivation problem.
Rust from a bag filter
in a refinery unit
[wint190.rd] GF-111 filter 8/12/04 red (40,30,zbc,tap
350
300
Intensity(Counts)
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200
150
100
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0
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Two-Theta (deg)
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Locate the peaks by interactive
deconvolution, and create
WINT190.PEAK
WINT190.PEAK
6.2904
4.8517
4.1888
3.6883
3.4385
3.2950
3.1251
2.9682
2.8207
2.7040
2.6365
12
12
1
7
2
11
15
30
2
22
2
2.5819
3
2.5309 100
2.5196 22
2.4723
9
2.4233
7
2.3596
4
2.2371
5
2.2097
5
2.0978 20
1.9350
5
1.9118
6
1.8431
1.7118
1.6968
1.6554
1.6300
1.6149
1.5982
1.5638
1.5244
1.4839
1.4546
8
5
12
3
6
23
1
1
2
32
6
Import into SIeve+
Data screen for SIeve+, candidate phases are shown at the top, with matched lines in
red. Identified phases are shown at the bottom left. Matched lines for each identified
phase are shown on the bottom right, with matches in blue, and peaks to be matched in
black. The candidate list strongly suggests ZnS as a match for the unmatched lines!
Magnetite, hematite, and lepidocrocite were
easy to identify (and expected components
of rust), but now we have to think…
ZnS would be very strange here,
so look far down (>100 hits) the list.
We start seeing F-cubic things with a = 5.407Å.
Do an author’s cell search for compounds with
lattice parameter around this value…
Selected criteria for a search using Cubic structures with a 5.40 cell edge
Could this be CeO2?
Bulk chemical analysis shows 2.1 wt% Ce,
so, yes!
And this is what the
customer wanted to know!
Note: The customer suspected that this was a contaminant,
but did not tell the analyst until after the analysis was conducted!
All the results, including the CeO2, are identified. SIeve+ also
provides integrated intensities and I/Ic values enabling a
quantitative analysis by the Reference Intensity Ratio method.
Simulation of the reference pattern identification as compared
to the raw data – all peaks identified and accounted for.
Compare the RIR concentrations to
those from a Rietveld refinement
Phase
Sieve+
GSAS
Magnetite
55 wt%
39.2(4)
Hematite
19
32.4(6)
Cerianite
13
2.7(1)
Lepidocrocite
12
25.6(6)
Note: SIeve+ provides a scaled simulation, not a refinement. Improved RIR results
would be expected from a refinement. Refined results are not provided by SIeve+,
but are provided with many OEM data analysis programs.
Conclusions
These examples demonstrate how different pieces of knowledge
about a sample can be combined, with the aid of data mining,
to solve complex problems.
In the three examples, the unknown was always a minor phase with
a small number of diffraction peaks identified through a residual peak
analysis. The use of XRF data, and/or a knowledge of the specimen
history, was cross referenced with the diffraction peaks to greatly
reduce the number of candidate materials that fit all the known
observations.
Thank you for viewing our tutorial.
Additional tutorials are available at the ICDD web site
(www.icdd.com).
International Centre for Diffraction Data
12 Campus Boulevard
Newtown Square, PA 19073
Phone: 610.325.9814
Fax: 610.325.9823