fusion-how to improve throughput by eleminating the loss
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FUSIONS – HOW TO IMPROVE THROUGHPUT AND
CONCENTRATION RANGE OF ANALYSIS BY ELIMINATING
THE LOSS ON IGNITION PROCESS STEP, USING DIFFERENT
DILUTION RATIOS AND MAINTAINING ACCURACY AND
PRECISION OF RESULTS
Laura Oelofse (Rigaku Americas) and Yoshijuro Yamada (Rigaku
Corporation )
Abstract
The use of fusions for XRF in industrial process monitoring is common
practice and there are several time consuming steps to complete in
order to render a sample fusion ready.
This paper details a method that would eliminate the need to carry out
the Loss on Ignition, Gain on Ignition step thus eliminating 2 hrs from
the preparation time and it also details the ability to use different
dilution ratios of sample and flux for materials on the same calibration
curve in order to increase the scope of materials that can be included in
a universal calibration curve using both naturally sourced certified
reference materials and synthetic pure chemicals as calibration
standards
Analysis Schemes in Various
Industry Sectors
Product Incoming Raw
Materials
Composition
varies in
narrow range
Widely
varying
composition
XRFs Role in High Throughput
Solutions
Results
Sample Preparation
Sample Loading
Sample Introduction
Analysis
Fusions – Flux + Sample
All compounds changed to oxide form
Eliminate Particle Size Effect
Eliminate Mineralogical Effect
6
Some Typical Fused Glass Beads
7
Why Preparation of Fused Glass Beads
• Particle size and mineralogical effects are removed or diminished by fusion of the sample with a suitable flux to form a glass bead.
• Synthetic calibration standards can be made by mixing pure oxides at concentration levels to suit the analytical range.
• Depending on sample type, fusion can even be quicker than pressed powder procedure.
• Generally accuracies and reproducibility are superior with fusion procedure.
• Only drawback is possible dilution of trace elements and therefore inferior LLD. Low dilution fusions are possible.
8
Preparation of
Fused Glass Beads
9499D00500
To standard holder
Melting method
Weigh outand mix
Flux + Specimen
Heat forMelting
Platinum crucible Remove bubbles
Glass diskspecimen
1000° -1100° C
Cast & Cool
8 - 15 mins
5 mins
3 - 7 mins
9
Preparation of Fused Glass Beads
• Preparation of powder as fused glass bead involves weighing out
sample and flux, placing in Gold/Platinum crucible, heating to 1000
– 1200 degrees and casting as a flat glass bead by pouring melt
into a heated Gold/Platinum mould and cooling under controlled
conditions.
• Newer alternative is moldable where melt remains in crucible and
bead is formed in situ.
• DEPENDING ON NATURE OF SAMPLE – LOSS ON IGNITION
MAY BE NECESSARY. ( CEMENTS, LIMESTONE, DOLEMITE)
In reality there are three types of samples Type 1 – Sample is stable, no loss or gain during fusion process
Type 2 : Sample loses CO2 or Intrinsic Waters during fusion, known as Loss on Ignition
Flux
S F
Sample
LOI
S Replaced with flux
Sample
B
Flux
Flux
LOI
S F
Sample
Type 3: Sample loses CO2 or Intrinsic Waters during fusion, known as LOI and changes oxidation state and pick up oxygen, gaining on ignition, known as GOI
GOI
Analytical Error Factors in Fusion Method The errors can be removed by Rigaku Bead Correction method
Powder Sample
Fusion Bead
Heterogeneity Effect
Grain-size Effect
Mineralogical Effect
Weighing Error
Loss on Ignition
Gain on Ignition
Evaporation of Flux
Error factors
for Bead
Error Factors in Fusion Method
Weighing Fusing
Weighing error
Bead
Sample
Flux(Li2B4O7 etc)
H2O CO2
LOI O2
FeO Fe2O3
GOI Flux evaporation
1000-1200˚ C
Pt crucible
The four error factors can be corrected.
(1) (2) (3) (4)
Strategy for the Corrections of LOI, GOI and Dilution Ratio
Model 1 : Use of Ratio of flux to sample weight ( F/S)
Definition of LOI : Imaginary component with no x-ray absorption Correction LOI(GOI) : Concentration is manually input or calculated as balance Dilution ratio : Corrected by manual input of F/S
Model 2 : Use of Ratio of bead to sample weight( B/S)
Flux
LOI
S F
Sample
Definition of LOI : Imaginary component of flux Correction : LOI(GOI) : Concentration is manually input or calculated as balance Dilution ratio : Corrected by manual input of B/S (Note) Flux evaporation can be corrected
LOI
S Replaced with flux
Sample
B
Flux
Analysis in Fused Beads
Use of fusion bead correction
Software generates theoretical alphas for LOI/GOI and dilution ratio
)RαWαWαKC)(1bI(aIWi FFLOILOIjj2
The alphas correct for
LOI/GOI
and Flux evaporation during fusing
Dilution ratio
Calibration equation
The alphas are generated by using a fundamental parameter software and it
generates variety of models.
Dilution ratio models : Flux weight to sample weight(F/S) or bead weight to sample weight(B/S)
LOI/GOI : Loss eliminated or manual input
Rigaku Fusion Bead Correction Software
• Allows for varying flux : sample ratios and the use of
catch weights
• Allows calculation of the Loss on Ignition /Gain on
Ignition and flux loss component by balance or ratio input
Oxides BCS376 LOI 0 LOI 10
SiO2 67.1 67.42 60.68
TiO2 0.02 0.02 0.02
Al2O3 17.7 17.79 16.01
Fe2O3 0.10 0.10 0.09
CaO 0.54 0.54 0.49
MgO 0.03 0.03 0.03
Na2O 2.83 2.84 2.56
K2O 11.2 11.25 10.13
LOI 0.35 0.00 10.00
Total 99.87 99.99 100.01
Sample (g) 0.3000 0.2700
Li2B4O7 ( g) 3.0000 3.0000 -10
0
10
20
30
40
50
60
0 20 40 60
LO
I X
RF
LOI CHEM
LOI CHEM
Lineær (LOI CHEM)
Fusion Bead Correction for LOI in Various Kinds of Materials
SiO2 TiO2 Al2O3 Fe2O3 MnO MgO CaO Na2O K2O P2O5 LOI
BCS393 Chem. 0.70 0.01 0.12 0.05 0.01 0.15 55.46 0.03 0.02 0.01 43.44
(Limestone) XRF 0.77 0.02 0.16 0.03 0.00 0.13 55.78 0.00 0.01 0.00 43.10
Diff. -0.07 0.01 0.04 -0.02 -0.01 -0.02 0.32 -0.03 -0.01 -0.01 -0.34
NBS69b Chem 13.57 1.92 49.29 7.21 0.11 0.09 0.13 0.03 0.07 0.12 27.46
(Bauxite) XRF 13.68 1.92 49.28 7.25 0.11 0.14 0.17 0.00 0.07 0.11 26.99
Diff. 0.11 0.00 -0.01 0.04 0.00 0.05 0.04 -0.03 0.00 -0.01 -0.47
NBS697 Chem 6.84 2.53 45.99 20.09 0.41 0.18 0.71 0.04 0.06 0.97 22.18
(Bauxite) XRF 6.88 2.51 45.98 20.15 0.42 0.25 0.78 0.00 0.06 0.97 22.00
Diff. 0.04 -0.02 -0.01 0.06 0.01 0.07 0.07 -0.04 0.00 0.00 -0.18
NBS97a Chem 44.00 1.91 39.06 0.45 0.00 0.15 0.11 0.04 0.50 0.36 13.42
(Clay) XRF 43.89 1.93 38.72 0.45 0.00 0.09 0.13 0.01 0.58 0.37 13.83
Diff. -0.11 0.02 -0.34 0.00 0.00 -0.06 0.02 -0.03 0.08 0.01 0.41
JDo 1 Chem 0.21 0.00 0.01 0.02 0.01 18.58 33.94 0.01 0.00 0.04 47.18
(Dolomite) XRF 0.28 0.01 0.06 0.01 0.00 18.87 33.95 0.00 0.00 0.03 46.79
Diff. 0.07 0.01 0.05 -0.01 -0.01 0.29 0.01 -0.01 0.00 -0.01 -0.39
BCS375 Chem 67.15 0.38 19.82 0.12 0.00 0.05 0.89 10.41 0.79 0.00 0.39
(Feldspar) XRF 67.80 0.38 20.05 0.10 0.00 0.07 0.87 9.95 0.74 0.01 0.03
Diff. 0.65 0.00 0.23 0.02 0.00 0.02 -0.02 -0.46 -0.05 0.01 -0.36
R801 Chem 78.64 0.10 16.76 0.17 0.00 0.04 0.04 0.22 0.18 0.00 3.86
(Pyrophyllite) XRF 78.62 0.10 16.71 0.17 0.00 0.08 0.08 0.16 0.19 0.02 3.88
Diff. -0.02 0.00 -0.05 0.00 0.00 0.04 0.04 -0.06 0.01 0.02 0.02
BCS314 Chem 96.40 0.19 0.77 0.53 0.01 1.81 1.81 0.05 0.09 0.00 0.10
(Silica brick) XRF 96.47 0.20 0.79 0.49 0.00 1.86 1.86 0.01 0.08 0.01 0.01
Diff. 0.07 0.01 0.02 -0.04 -0.01 0.05 0.05 -0.04 -0.01 0.01 -0.09
Results are obtained by using theoretical alphas and LOIs are
obtained as balance. The accuracy of the calculated LOI across the
range of 0 % - 50% is 0.5%
Quantification and
Correction of Gain
on Ignition
Synthetic mixtures of SiO2 and
FeO were blended to yield
30%, 50% and 70% FeO
During fusion the FeO is
oxidized to Fe2O3 and there is
a weight gain of
(Fe2O3 – 2FeO)/ 2FeO
The mass absorption
coefficient of GOI is set to zero
and the value is considered as
a negative LOI in the FP
calculation.
The WFe2O3 = WFeO + W GOI
SiO2 FeO Fe2O3
calc.
Recalc.
FP value
70.00 30.00
32.27
32.48
calc.
Recalc.
FP value
50.00 50.00
52.64
52.84
calc.
Recalc.
FP value
30.00 70.00
72.17
72.15
Determination of GOI from Standard Iron Ore
Fe2O3 Diff
Chem XRF
JSS 803-2 89.57 89.71 0.14
JSS830-3 84.18 84.16 -0.02
Euro 680-1 86.33 86.31 -0.02
ASCRM 004 89.43 89.51 0.08
• Method applied to iron ore with high Fe content and
shown to be suitable
Dilution Ratio Correction STD
S:F 1:5
JB-2
UNK
S:F 1:10
JG-1
Lit. FP Lit.
SiO2 52.83 73.06 72.75
TiO2 1.18 0.28 0.26
Al2O3 14.57 14.02 14.29
Fe2O3 14.24 2.13 2.21
MnO 0.20 0.06 0.06
MgO 4.63 0.71 0.75
CaO 9.82 2.18 2.19
Na2O 2.02 3.38 3.41
K2O 0.43 4.10 3.97
P2O5 0.10 0.09 0.10
Application of LOI, GOI and dilution ratio correction to
Empirical Calibration Methods
• Matrix correction coefficients were theoretically calculated for LOI,
GOI and dilution ratio correction components
• The matrix correction expression including the dilution ratio
correction is shown on the next slide
• Using the Theoretical Alpha Correction model where the base
component is considered to be the LOI/GOI/D.C then these are
eliminated in the De Jongh calculation and are calculated as a
balance component.
• The accuracy for Fe2O3 in a regression of geological standards for
an uncorrected calibration was 0.161%, for a calibration with
conventional matrix corrections 0.066% and for theoretical matrix
correction coefficients with LOI and GOI correction an improved
accuracy of 0.056%
Rigaku Theoretical Alphas for Fusion Bead
Correction equation of T.Fe
Wi = (aiIi2+biIi +c)*(1+SajWj + aFRF - KF)
Factor Coefficient
K 0.910900
a(T.Fe) 0.002392
a( SiO2) 0.001413
a(Mn) 0.002923
a(CaO) 0.006793
a(MgO) 0.000967
a(Al2O3) 0.001128
a(TiO2) 0.006700
a(P) 0.003929
a(S) 0.004874
a(K) 0.008125
a(FLUX) 0.089130
1. The correction coefficients a j for inter-elements and flux
are calculated theoretically by Rigaku/FP software. These
alphas depend on the optics of spectrometer.
2. K corresponds to the standard dilution ratio.
3. When the actual dilution ratio “ RF” ( Bead weight/ sample
weight ) is input for the each sample manually, all error
factors are automatically corrected. ( LOI, GOI and Dilution
Correction)
4. Calibration constants (a,b,c) are calculated using the non-
linear regression equation , after standard samples are
measured.
Dilution Ratio Correction
aa
FFF
Ljjjii KRW1cIbW
Calibration equation with dilution ratio correction
FFF RK a
aa FFjjii RW1cIbW
General calibration equation
FFF RRR RF : Difference between the actual
and standard ratio
RF : Actual dilution ratio aFRF + KF is the correction term for
the difference between the actual and standard dilution ratio.
Matrix Correction Model
Correction model Uncorrected component
Notes
Lachance-Traill Analyte Correction by all the components except the analyte. The calibration curve is linear.
de Jongh Base component Correction by all the elements except the base component. The calibration curve is linear.
JIS Base component
and analyte
Correction by all the elements except the base component and the analyte. The calibration curve is linear or quadratic.
When a significant amount of LOI (GOI) is contained, it is advisable to use de Jongh or JIS model.
SiO2 Calibration Curve
Standard value (mass%)
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Standard value (mass%)
de Jongh model JIS model
Analysis sample: rock fusion disk (dilution ratio 5:1)
considering self-absorption by the analyte
Accuracy: 0.18 mass%
Accuracy: 0.17 mass%
CaO Calibration Curve
Standard value (mass%)
X-r
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X-r
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Standard value (mass%)
de Jongh model JIS model
Analysis sample: rock fusion disk (dilution ratio 5:1)
considering self-absorption by the analyte
Accuracy: 0.17 mass% Accuracy: 0.14 mass%
Comparison of Matrix Correction Coefficients between Several Materials by the Fusion Method
— Analysis of Refractories —
Calibration Range of the Major Components and
Dilution Ratio for Each Material
Material Major component (mass%) Dilution ratio
(Flux/Sample) SiO2 Al2O3 Fe2O3 MgO Cr2O3 ZrO2
Clay 37–86 6–49 –5 –1 –1 10
Silica 84–97 –10 10
High alumina –44 47–94 10
Magnesia 81–99 10
Chrome-magnesia –27 10–52 2–53 22.16
Zircon-zirconia –45 48–92 10
Alumina-zirconia-silica –42 10–82 12–48 10
Alumina-magnesia 10–93 3–79 10
The whole range –97 –94 –27 –99 –53 –92 10–22.16
• Wide calibration range • Different dilution ratio
• Flux: Li2B4O7
• LiNO3 was used just for Chrome-magnesia.
Comparison of Matrix Correction Coefficients for Each Material (1)
Clay High alumina Alumina-Zircon-Silica
Analyte SiO2
Correcting comp. Si-Ka
Al2O3 1.38E-03 1.38E-03 1.37E-03
Fe2O3 1.02E-03 1.01E-03 1.02E-03
TiO2 2.44E-04 2.41E-04 2.43E-04
MnO 8.65E-04 8.62E-04
CaO 6.91E-05 6.60E-05 6.81E-05
MgO 1.33E-03 1.33E-03 1.33E-03
Na2O 1.04E-03 1.04E-03 1.04E-03
K2O -5.41E-05 -5.75E-05 -5.49E-05
P2O5 -1.88E-05
Cr2O3 6.06E-04 6.07E-04
ZrO2 8.76E-04 8.68E-04
Correction model: Lachance-Traill
Correction coefficients are almost identical for each material.
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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SiO2 Calibration Curve
◆ 10 : 1 ◆ 22.16 : 1
(Chrome-magnesia)
Accuracy: 0.25 mass%
Silica
Clay
AZS
Magnesia
AZS
Chrome-magnesia
AZS: Alumina-zirconia-silica
Magnified
Comparison of Matrix Correction Coefficients for Each Material (2)
Clay High alumina Alumina-Zircon-Silica
Analyte Fe2O3
Correcting comp. Fe-Ka
SiO2 -1.88E-03 -1.87E-03 -2.06E-03
Al2O3 -2.19E-03 -2.18E-03 -2.37E-03
TiO2 3.93E-03 3.95E-03 3.64E-03
MnO -1.94E-04 -1.93E-04
CaO 4.03E-03 4.04E-03 3.72E-03
MgO -2.37E-03 -2.36E-03 -2.54E-03
Na2O -2.62E-03 -2.61E-03 -2.79E-03
K2O 3.94E-03 3.96E-03 3.64E-03
P2O5 -1.65E-03
Cr2O3 7.27E-03 6.91E-03
ZrO2 1.09E-03 1.30E-03
Correction model: Lachance-Traill
Correction coefficients are almost identical for each material.
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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Fe2O3 Calibration Curve
◆ 10 : 1 ◆ 22.16 : 1
(Chrome-magnesia)
Accuracy: 0.029
mass%
Zircon-zirconia
Magnesia
Chrome-magnesia
AZS: Alumina-zirconia-silica
Chrome-magnesia
Magnified
Dilution Ratio Correction + Matrix Correction
Rock sample : dilution ratio 10:1 and 5:1
Analyte : SiO2
Analysis sample CCRMP: SY-2, SY-3
GSJ: JA1, JA2, JA3, JB2, JB3, JG1a, JG2, JG3, JGb1, JR1, JR2, JLs1, JCp1
Standard value (mass%)
X-r
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a. u
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Standard value (mass%)
X-r
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Dilution Ratio Correction Rock sample : dilution ratio 10:1 and 5:1
Analyte : SiO2
●:5:1 ●:10:1
Accuracy: 11 mass%
No correction
Accuracy: 3.6 mass%
Dilution ratio correction
●:5:1 ●:10:1
The dilution ratio correction improves the accuracy; however, the fitting is
still not excellent due to matrix effect.
Standard value (mass%)
X-r
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Standard value (mass%)
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Dilution Ratio Correction + Matrix Correction
Rock sample : dilution ratio 10:1 and 5:1
Analyte : SiO2
● 5:1 ● 10:1
Accuracy: 0.33 mass%
Dilution ratio cor.
+ Matrix cor. Accuracy: 3.6 mass%
Dilution ratio correction
● 5:1 ● 10:1
The combination of the dilution ratio and matrix corrections enables
an excellent fitting.
LOI Correction (1)
• Test sample: rock sample with 50 mass% LOI
(the bead was made with the dilution ratio 10:1, and then treated as the dilution ratio 5:1, which results in the sample with 50 mass% LOI.)
• Analyte: SiO2
LOI Correction and Matrix Correction Coefficients
Without LOI cor. With LOI cor.
Base component SiO2 LOI
Na2O -4.79E-04 5.15E-03
MgO -6.32E-05 5.81E-03
Al2O3 5.91E-03
SiO2 -1.97E-03 2.78E-03
P2O5 -1.99E-03 2.74E-03
K2O -2.03E-03 2.67E-03
CaO -1.87E-03 2.94E-03
TiO2 -1.61E-03 3.35E-03
MnO -7.21E-04 4.76E-03
Fe2O3 5.03E-04 5.11E-03
Correction model: de Jongh Element line: Si-Ka
Standard value (mass%)
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Standard value (mass%)
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Matrix Correction (without LOI Correction)
Analyte : SiO2
● w/o LOI ● with LOI
Accuracy: 3.5 mass%
Matrix correction
Accuracy: 2.5 mass%
No correction
● w/o LOI ● with LOI
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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LOI Correction and Matrix Correction
Analyte : SiO2
● w/o LOI ● with LOI
Accuracy: 3.5 mass%
Matrix correction
Accuracy: 0.26 mass%
LOI correction + Matrix cor.
● w/o LOI ● with LOI
Wide Analysis Range in XRF
Analysis of Diverse Natural
Minerals
by the Fusion Method
(Synthetic Fusion Bead Added)
Purpose of This Test Analysis
• To obtain a good fitting for calibration curves with wide concentration range of diverse natural minerals by the fusion method
• To obtain a good fitting for calibration curves with synthetic
standard fused beads
Reference Materials for Calibration (1) Sample Material Dil. ratio Sample Material Dil. ratio
BAS203a Talc 10 NBS688 Basalt rock 10
BCS313-1 High purity silica 10 SRM 1c Limestone 10
BCS314 Silica brick 10 SRM 69b-1 Bauxite 10
BCS315 Fire brick 10 SRM 696 Bauxite Surinam 10
BCS319 Magnesite 10 SRM 697 Bauxite Dominican 10
BCS368 Dolomite 10 SRM 698 Bauxite Jamaican 10
BCS369 Magnesite-Chrome 22.167 SRM 70a Potash feldspar 10
BCS370 Magnesite-chrome 22.167 SRM 99a Soda feldspar 10
BCS375 Soda feldspar 10 R-603 Clay 10
BCS376_1 Potash feldspar 10 R-701 Feldspar 10
BCS358 Zirconia 10 R-801 Pyrophyllite 10
BCS388 Zircon 10 JSS009-2 Pure iron oxide 10
BCS389 High purity magnesium 10 JRRM511 Chrome-magnesia 22.167
BCS393 Limestone 10 JRRM602 Zirconia 10
BCS394 Calcined bauxite 10 JRRM701 AZS 10
BCS395 Bauxite 10 RM-611 Portland cement 10
NBS98a Plastic clay 10 RM-612 Portland cement 10
NBS120c Florida phosphate rock 10 RM-613 Portland cement 10
Reference Materials for Calibration (2) Sample Material Dil. ratio Notes
ECISS782-1 Dolomite 10
ECISS776-1 Fire brick 10
BCS348 Ball clay 10
NIST 81a Glass sand 10
NIST 278_1 Obsidian rock 10
NIST 1413 Glass sand 10
NBS694 Phosphate rock 10
BAS 683-1-(1) Iron ore sinter 10.13
BAS 683-1-(2) Iron ore sinter 10.13
BCS315_Co1 Fire brick with Co AA standard sol. 10 For analysis of Co from the WC container
BCS315_W1 Fire brick with W AA standard sol. 10 For analysis of W from the WC container
NIST278_1_Co05 Obsidian rock with Co AA standard sol. 10 For analysis of Co from the WC container
NIST278_1_W05 Obsidian rock with W AA standard sol. 10 For analysis of W from the WC container
TiO2_10 TiO2 reagent 10 To extend TiO2 calibration range
P2O5_25 LiPO3 reagent 10 To extend P2O5 calibration range
K2O_50 K2CO3 reagent 10 To extend K2O calibration range
CaO_100 CaCO3 reagent 10 To extend CaO calibration range
Na2O_25 Na2CO3 reagent 10 To extend Na2O calibration range
Calibration Range
Analyte Calibration range Analyte Calibration range
Na2O 0 – 25 Fe2O3 0 – 99.84
MgO 0 – 96.7 Cr2O3 0 – 52.51
Al2O3 0 – 88.8 ZrO2 0 – 92.7
SiO2 0 – 99.78 HfO2 0 – 1.63
P2O5 0 – 33.34 SO3 0 – 6.07
K2O 0 – 50 SrO 0 – 0.28
CaO 0 – 100 Co2O3 0 – 1.407
TiO2 0 – 10 WO3 0 – 1.261
MnO 0 – 0.596 Li2B4O7 10 – 22.167 Dilution ratio (flux/sample)
Unit: mass%
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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Na2O calibration
Accuracy: 0.048 mass%
Accuracy: 0.40 mass%
MgO calibration
Na2CO3
Synthetic bead
BCS370 Mg-Cr
BCS369 Mg-Cr
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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Al2O3 calibration
Accuracy: 0.23 mass% Accuracy: 0.35 mass%
SiO2 calibration
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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P2O5 calibration
Accuracy: 0.017 mass% Accuracy: 0.056 mass%
SO3 calibration
LiPO3
Synthetic bead
Portland cement
Phosphate rock
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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K2O calibration
Accuracy: 0.021 mass% Accuracy: 0.27 mass%
CaO calibration
K2CO3
Synthetic bead CaCO3
Synthetic bead
Standard value (mass%)
X-r
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Standard value (mass%)
X-r
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TiO2 calibration
Accuracy: 0.027 mass% Accuracy: 0.067 mass%
Fe2O3 calibration
TiO2
Synthetic bead Fe2O3
Synthetic bead
Iron ore
Summary • By applying the dilution ratio correction, LOI correction and matrix
correction (theoretical alphas), it is possible to obtain a good fitting for calibration curves with wide concentration range for diverse natural rocks and minerals by the fusion method.
• With a few calibration standards, it is necessary to use the de Jongh or Lachance-Traill models, where calibration curves are linear in theory. In this test, de Jongh model was used because some samples contain significant LOI content.
• With a large number of calibration standards, it is possible to use the JIS model, where calibration curves can be quadratic.
• With synthetic fused beads to extend the calibration range, it is possible to obtain a good fitting for calibration curves.
Conclusion • The fusion bead method is useful sample preparation for eliminating
hetrogeneity effects, particle size effects, however chemical
reactions can cause the sample weight to decrease or/and increase
during fusion because of volatilization of H2O, CO2 and oxidation.
• It is possible to correct error factors in fusion for either the FP
method or the Empirical Calibration method.
• It is possible to skip the lengthy independent LOI step in preparing
the samples for fusion, by incorporating the step into the fusion
process and correcting for the associated losses and/or gains via
the correction methods just detailed
• It is possible to weigh catch weights and have them recorded in the
dilution correction.
• The time savings realized by eliminating the LOI step and supporting
varying dilution ratios improves throughput and cuts the analysis
cost per sample
• Thank you for your attention