Data Mining – Trace Phase Analysis - ICDD

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Nov 20, 2013 (3 years and 11 months ago)

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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

An
alytical
S
ciences
R
esearch
S
ervices

INEOS Technologies

James.Kaduk@ineos.com

A Vanadium Phosphate Catalyst for the Oxidation of
Butane

to Maleic Anhydride

x10^3
10
20
30
40
Intensity(Counts)
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)
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
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 1

2.4649 2

2.4415 15

2.3997 2

2.3665 5

2.2550 1

2.2123 1

2.0946 19

2.0780 5

1.9916 1

1.9730 1

1.9377 7

1.9026 2

1.8420 9

1.8293 2

1.7939 1

1.7503 1

1.7147 1

1.6488 3

1.6373 5

1.6257 1

1.6007 3

1.5781 10

1.5604 1

1.5232 1

1.5073 2

1.4925 1

1.4757 5

1.4611 5

1.4458 1

1.4210 3

1.3920 1

1.3840 4

1.3525 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.

10
20
30
40
50
60
70
80
90
Two-Theta (deg)
x10^3
5.0
10.0
15.0
20.0
Intensity(Counts)
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
00-050-0380> (VO)2P2O7 - Vanadyl Phosphate
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.

x10^3
5.0
10.0
15.0
20.0
Intensity(Counts)
00-050-0380> (VO)2P2O7 - Vanadyl Phosphate
00-047-0967> H4V3P3O16.5∙xH2O - Hydrogen Vanadium Phosphate Hydrate
10
20
30
40
50
60
70
80
90
Two-Theta (deg)
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
At the time of this analysis,

no structure had been reported for

H
4
V
3
P
3
O
16.5
(H
2
O)
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 ~7.21
Å.

There are still peaks at 3.5823 and 3.0760
Å.


Look for phases which have strong peaks

3.55
-
3.61 and 3.05
-
3.11 Å.

x10^3
5.0
10.0
15.0
20.0
Intensity(Counts)
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
10
20
30
40
50
60
70
80
90
Two-Theta (deg)
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
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 3.985
Å.

x10^3
5.0
10.0
15.0
20.0
Intensity(Counts)
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
10
20
30
40
50
60
70
80
90
Two-Theta (deg)
[goed80.raw] 21228-95-5 (40,40,0.3) JAK
Add to the refinement

The quantitative analysis is:

(VO)
2
P
2
O
7

84.8(1) wt%

H
0.6
(VO)
3
(PO
4
)
3
(H
2
O)
7

5.9(1) wt%


-
VOPO
4

5.6(1) wt%

β
-
VO(PO
3
)
2

3.7(1) wt%

A Deactivated Pd/C

Hydrogenation Catalyst

10
20
30
40
50
60
70
80
90
Two-Theta (deg)
x10
3
2.0
4.0
6.0
8.0
10.0
12.0
Intensity(Counts)
[nube157.raw] 22247-126D-(UCB-0308-014)/ Fines/ (40,40,0.3) TN
00-046-1043> Palladium - Pd
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 4.05
Å.

Pd and long line 4.05

0.02
Å

The search finds a number of Pd alloys, most have the formula XPd3.

10
20
30
40
50
60
70
80
90
Two-Theta (deg)
x10
3
2.0
4.0
6.0
8.0
10.0
12.0
Intensity(Counts)
[nube157.raw] 22247-126D-(UCB-0308-014)/ Fines/ (40,40,0.3) TN
00-046-1043> Palladium - Pd
00-050-1631> Zvyagintsevite - PbPd
3
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

10
20
30
40
50
60
70
80
90
Two-Theta (deg)
0
50
100
150
200
250
300
350
Intensity(Counts)
[wint190.rd] GF-111 filter 8/12/04 red (40,30,zbc,tap
Locate the peaks by interactive
deconvolution, and create
WINT190.PEAK

6.2904 12

4.8517 12

4.1888 1

3.6883 7

3.4385 2

3.2950 11

3.1251 15

2.9682 30

2.8207 2

2.7040 22

2.6365 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 8

1.7118 5

1.6968 12

1.6554 3

1.6300 6

1.6149 23

1.5982 1

1.5638 1

1.5244 2

1.4839 32

1.4546 6

WINT190.PEAK

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 = 5.407
Å
.


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 CeO
2
?


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.

International Centre for Diffraction Data

12 Campus Boulevard

Newtown Square, PA 19073

Phone: 610.325.9814

Fax: 610.325.9823

Thank you for viewing our tutorial.

Additional tutorials are available at the ICDD web site
(
www.icdd.com
).