XRF and TGA Commissioning outcomes at
Cape Lambert Port B
R.W.Brunning, C. Andringa-Bate
Rio Tinto Iron Ore
Introduction
The Cape Lambert Port B (CLB) project comprises the construction of a new Port facility adjacent to the
Cape Lambert Port A facility (CLA). This involved the construction of a new 100Mt/a train unloading
infrastructure, stockyard, ship-loading facilities (including a new ore wharf) and the construction of an
automated sampling and analysis laboratory. Figure 1 shows CLB layout with the stockpiles in the
background, followed by the rescreening plant and the pale large building in the foreground which
houses the CLB sampling facility and analytical cell.
Laboratory
Figure 1. The photograph shows the location of Cape Lambert Port B Laboratory in the foreground
RTIO has traditionally designed and commissioned laboratories using semi-automated sample weighing
systems, fusion machines, Thermo-Gravimetric Analysers (TGA’s) and XRF spectrometers to process the
numerous samples produced from mining, processing and ship-loading activities. At CLB the sample
station and preparation facilities are fully automated, providing crushing, dividing, drying and sieving
operations. Although not originally in the scope of works, automated, analytical cell facilities were
added to the project to reduce the need to transport samples around the site.
In 2012 RTIO/SKM/IMP commenced work for the design and development of the analytical facility at
Cape Lambert Port B. The analytical facility would need to have the capacity to process cargos totaling
100Mt/a at ship-loading rates of 13,440tphr. During loading, individual cargos are composited within the
sampling cell for chemical analysis. On completion of loading the cargo; composite material is crushed,
pulverized and sub-sampled before being presented for XRF and TGA analysis. The analytical cell
comprises a vial storage magazine and a HAG-HF (fusion/weigh cell) interfaced to an Axios XRF
spectrometer and automated TGA system.
Figure 2 CLB Analytical Cell Layout
The new automated analytical facilities were required to have accuracy and a precision as good or better
than current port laboratory facilities. This paper examines the results of XRF calibration and TGA
analysis commissioning between August and December 2013. Analytical results obtained from the cell
are evaluated against the iron ore international standards for chemical analysis ISO9516 (2003 - Iron
Ores - Determination of various elements by X-ray Fluorescence Spectrometry) and hygroscopic moisture
ISO2596 (2006 - Iron ores – Determination of Hygroscopic moisture in analytical samples- Gravimetric,
Karl Fischer, and mass-loss methods).
Method
Weighing and HAG-HF Fusion
The CLB HAG-HF unit comprises of a weigh cell (Figure 3), two fusion ovens (Figure 4), and a citric acid
bath, water bath and air drying to allow cleaning of crucibles and molds. Crucibles and molds are moved
between the various areas in the HAG-HF by a single pivot mounted Mitsubishi robot. The CLB HAG-HF
design enables the continuous fusion of samples introduced via the vial storage magazine as cargo
samples are presented. The vial storage magazine also enables the introduction of general QA/QC
standards and other ad-hoc samples.
Figure 3 HAG-HF weigh cell for fusion and TGA
Figure 4 HAG-HF Oven layout
The HAG-HF fusion ovens were utilized for the fusion of all XRF calibration samples. However, calibration
samples were manually weighed external to the HAG-HF due to the small weights of pure oxides to be
used and the numerous binary compounds to be fused. Calibration samples were introduced into the
HAG-HF via a manual sample input. All test samples were introduced via the vial storage magazine
utilizing the HAG weigh cell, fusion and cleaning facilities in order to evaluate TGA and XRF performance.
All test standards were allowed to equilibrate to the laboratory atmosphere over a 12hr period prior to
hygroscopic moisture analysis as required by ISO2596. Performance of TGA and XRF system was based
on the using a range of RTIO standards certified using ISO accredited methods.
Automated TGA
The HAG-HF is interfaced to the automated TGA and XRF units via a series of transport conveyors. The
HAG-HF unit extracts a test sample (2g) into a small ceramic crucible for full TGA analysis. A conveyor
then transfers the test sample from the HAG-HF to the TGA. The automated TGA set-up comprises of
four TGA units in which the sample is weighed upon entry into the first TGA (hygroscopic moisture) and
weighed at the completion of 1hr. The test sample is then rotated through the three remaining TGA’s
using the ‘automated transport mechanism. The residence time at each TGA unit is approximately 1hr.
The three remaining TGA’s are individually set at 425°C, 650°C and 1000°C. Each TGA remains at its predefined temperature, and crucibles containing ore samples (as well as crucible blanks) are rotated from
furnace to furnace. Blank crucibles are used to calculate furnace factors. After ignition at 1000°C, the
crucible is removed, allowed to cool prior to being air-cleaned, ready for re-use. Figure 5 shows the four
blue TGA units with the automated transport mechanism suspended above the TGA units.
Figure 5 CLB automated TGA system
Reported shipment grades are based on a calculated iron (Calc Fe %) grade on a dry basis as detailed in
Equation 1 below
Calc Fe % = (100 – oxides % at 1000C] – LOI1000C ) / 1.4297
(1)
Where 1.4297 is the factor used to convert Fe to Fe2O3.
It is imperative that LOI and all elemental analyses for an iron ore are determined accurately and
precisely. Since these are required to be corrected to a dry weight basis, accurate hygroscopic moisture
determination is of great importance. A simple method developed with the assistance of CSIRO (Division
of Minerals) enables the testing of several ores simultaneously for hygroscopic moisture in a single cycle
of a ‘Parcher’ apparatus (Figure 6). As detailed in ISO2596, hygroscopic moisture is determined by
heating a known quantity of ore at 105°C under a stream of nitrogen for 2hrs. Copper sulphate
pentahydrate has a known loss of 28.5-29.25% when heated under these conditions and can be seen in
the third position from the left in Figure 7. The copper sulphate pentahydrate standard was periodically
analysed with standards to ensure correct operation of the Parcher apparatus.
Figure 6 Parcher apparatus
Figure 7 Ore samples place into parcher (prior to heating)
The first TGA oven to which the ore sample is introduced for hygroscopic moisture determination has
been designed to simulate as closely as possible the conditions used in the Parcher apparatus. A hollow
alumina lid allows each crucible at any position to be purged with nitrogen from above (Figure 8). Given
shipping operations are continuous and the TGA system will also operate continuously, a nitrogen
generator has been installed at CLB to supply nitrogen of >99.9% purity to TGA 1. However, during the
commissioning phase industrial grade bottles nitrogen banks were used to purge TGA 1.
Figure 8 TGA 1 lid inverted showing small nitrogen inlet holes
The importance of introducing a nitrogen atmosphere into the first TGA was examined during
commissioning. A series of 12 iron ore replicates was tested with the nitrogen on and off to examine the
effects of an inert atmosphere.
The hygroscopic moisture loss through parching the materials should be equivalent to the weight loss in
TGA 1 prior to the sample proceeding to TGA 2. A series of samples with various mineralogies were
tested over a period of six weeks to examine the accuracy and precision of the TGA 1 compared to the
Parcher method. In each test the recommendations of ISO2596 were adhered to in terms of
equilibration of samples in the laboratory atmosphere prior to analysis.
Using a variety of internal standards (which have been certified using only applicable ISO methods), the
performance of the remaining TGA’s for LOI at the various intermediate and final temperatures was
evaluated.
XRF Calibration
The CLB Port analytical laboratory will be expected to analyse 100-150 samples daily when full shiploading rates are achieved in late 2014. The two fusion induction furnace (HAG-HF) arrangement
commercially produced by Herzog shown in Figure 9 below is capable of fusing this volume of samples
Figure 9 CLB HAG-HF Fusion Unit
The HAG-HF fuses two samples simultaneously using two induction ovens, producing 32mm glass discs.
At Cape Lambert A and all other RTIO laboratories, 40mm discs are produced. The fused beads at CLB
were produced using 0.43g of sample to 4.4g of 12-22 lithium metaborate tetraborate flux. These
sample/flux weights are within the parameters specified for the production of 32mm fused discs in
ISO9516. The furnaces inductively heat the samples through a series of mixing and homogenization
steps prior to casting into a flat mold. Increased fusion times approaching 20minutes were utilized for
the fusion of calibration discs. All calibration samples were weighed and mixed with flux manually due to
the low weights of pure chemicals used rather than using the automated dispensing facilities within the
HAG-HF. Some 120 calibration beads were produced over a period of 10 days.
RTIO has traditionally used a series of pure standards with a commercially available synthetic calibration
standard (Syncal, XRF Scientific Batch Number 070708DB) to calibrate its XRF’s. The Syncal is mixed at
various ratios with silicon dioxide (min 99.99% SiO2) or iron oxide (min 99.998% Fe2O3) to increase the
number of calibration points for various minor and trace elements. Progressing from the mid 1990’s,
RTIO has increased the number of elements analysed from 14 to 24. The latest elements to be added
routinely for analysis have been Na and Cl. XRF Scientific introduced Na and Cl into the Syncal matrix in
2008 as NaCl on request from iron ore producers. As ISO9516 requires treatment of the pure
compounds to eliminate moisture and contamination, the Syncal standard was prepared by ignition in a
muffle furnace manually at 900°C for 20mins. This treatment of the Syncal had detrimental effects for
the As, Pb, K2O and Cl calibrations as detailed in the results section.
The inductive heating of the HAG-HF combined with the transport of molds and crucibles to and from
weigh cell–fusion-cleaning cell requires the platinum-ware to be resistant to high temperature and
robot gripping forces. Crucibles were manufactured using a 95%Pt/5%Au/0.2%ZrO2 alloy whilst
95%Pt/gold were used for the molds. The Pt/Au/Zr alloy is considerably harder than the normal Pt/Au
alloy. Temperature calibration of the furnaces is configured using an optical pyrometer which monitors
the exterior wall of the crucibles as they are heated.
Results
HAG-HF Fusion
The HAG-HF fusion equipment at CLB produces 32mm glass beads with the flux and sample weights of
4.4g and 0.43g respectively (ratio of 10.2:1). The HAG-HF fusion machine is programmed to pre-weigh a
small amount of flux followed by dosing 0.43g of sample, and finally topping with flux to achieve the
ideal sample ratio prior to mixing. Table 2 shows the sample and flux weights and ratio’s achieved over a
period of a single month running 60 unknown standards provided by Geostats. As can be seen in Table
2, all samples are well within the range of the weights specified in ISO9516, and the flux to sample ratio
is extremely small in variability.
Table 1 Flux and sample masses dispensed by the HAG-HF over a period of a month
Flux / Sample masses achieved from the HAG
ISO9516 / g
Flux
4.1 - 4.61
Sample 0.41 - 0.44
Mean Mass / g
4.2653
0.4171
Target Flux/Sample Ratio
Min Flux/Sample Ratio
Max Flux/Sample Ratio
Min Mass /g Max Mass / g
4.2044
4.4049
0.4134
0.4308
10.23
10.16
10.29
The HAG-HF produces beads through high temperature induction, whereby the temperature of the melt
is monitored by an optical pyrometer measuring the outside crucible wall temperature between the
induction coils. Initial sulphur losses as per ISO9516 (duplicate CaSO4/Fe2O3 fusions) indicated a small
0.1% difference between duplicates on S count rates. (<2% is considered acceptable). After several
weeks of operation however, sulphur content of shipment sample duplicates showed concentration
differences of 0.01% as is indicated in Table 2.
Table 2 Failure of sulphur on duplicate samples at the CLB laboratory
Sample ID
Average Result
A11
A12
Average Result
B11
B12
Average Result
A21
A22
Average Result
B21
B22
S/%
0.015
0.013
0.017
Fail S
0.016
0.006
0.016
0.016
0.015
Fail S
0.016
0.007
The large difference between duplicate analyses was traced back to the fusion process, which was
observed to be exceeding the set temperature of 1050°C both visually and experimentally (verified using
a thermocouple). While the over temperature problem was resolved by adjusting the feed to the
induction coil, introduction of new platinum-ware still causes fusion temperature to significantly
increase. Sulphur losses were evaluated by preparing duplicate 10% CaSO4 90% Fe2O3 beads using old
and new crucibles (Figure 10). Fusion of the CaSO4/Fe2O3 mixture in a new and old crucible showed a
17% difference in sulphur count rates, while less than 2% is considered acceptable according to ISO9516.
The newer crucible showed the lower sulphur count rates, indicating overheating and sulphur loss
during the fusion process. We are currently investigating whether the temperature of the melt could be
monitored rather than the temperature of the platinum crucible wall to eliminate sensitivity of the
temperature control mechanism to the platinum surface. Alternatively temperature calibrations may
need to be performed when old crucibles are replaced.
Figure 10 - Old and new crucible exterior wall
Automated TGA
The automated TGA instrumentation determines the hygroscopic moisture, intermediate LOI’s at 425°C
and 650°C and final LOI at 1000°C of iron ore samples introduced. During commissioning the hygroscopic
moisture was evaluated using the automated TGA concurrently with determinations on the Parcher
apparatus at 105°C. Copper sulphate pentahydate sample losses during the initial commissioning of the
Parcher averaged 28.6% (expected 28.5-29.25%), confirming the Parcher to be accurate in hygroscopic
moisture determination. In October 2013, TGA 1 was changed from a routine ceramic based furnace to
an alumina block furnace in which there are multiple N2 purging points compared to 2 points in the
ceramic based TGA. The temperature we tested and adopted for hygroscopic moisture is 140°C. There
are 47 bench-top TGA’s in our Pilbara operations and previous test-work has indicated that most TGA’s
need to operate at a temperature of 140°C for the hygroscopic moisture step. Figure 11 shows the
comparative results for TGA 1 hygroscopic moisture determination (140°C alumina block oven, nitrogen
flow 6 litres per minute) versus Parcher hygroscopic moisture determination for a series of standards. As
Figure 11 shows, the data shows only periodic agreement between the two determinations during the
test period
Figure 11 Difference between TGA1 and Parcher (ISO2596) on a series of standards and samples at 140°C between Nov 2013
and Jan 2014
The agreement between Parcher and TGA hygroscopic moisture determinations appears to improve
when the difference between the TGA1 and HAG approaches 0.000g. A slightly positive difference
between the two weigh cells causes the TGA moisture to be below the Parcher moisture as seen in
Figure 11, in mid-January. The TGA1 hygroscopic moisture is calculated according to Equation 2
Hygroscopic Moisture % =
–
(2)
All three parameters in the equation are to be investigated to ensure agreement between Parcher
moisture and TGA1 moisture can be maintained. The alignment between the HAG and TGA 1 weigh cells
needs to be carefully monitored and maintained to ensure good correlation between the automated
TGA and the ISO accredited Parcher method.
Previous test work has also indicated that nitrogen flow is required to ensure a uniform temperature
profile across the furnace as well as ensure rapid drying of the samples within the furnace. Introduction
of a dry, inert gas such as nitrogen theoretically decreases the vapor pressure above the samples,
allowing hygroscopic moisture to be more rapidly evolved. A test in which 12 repeat Robe Valley Pisolite
(RVP) standard samples were run in two separate trials with the nitrogen on and off were examined. The
results of the trial are shown in Table 4. The introduction of nitrogen is necessary to achieve the correct
hygroscopic moisture and subsequent LOI values. Without the nitrogen flow, the hygroscopic moisture
differed from the Parcher determined values by an unacceptable 0.60%, while introducing nitrogen flow
produced values in agreement within 0.15%. Arguably the residence time of samples could be increased
in TGA 1 with no nitrogen flow, but similar increased residence time would be required for TGA 2, 3 and
4 due to the TGA control process. This time becomes impractical in terms of throughput as the total
analysis time will be in excess of 4hours. Additionally temperature of TGA1 furnace shouldn’t be
increased above 140°C so as to avoid introduction of a positive bias between the TGA1 moisture step
and Parcher (as can be seen in some periods of Figure 11). Table 3 clearly demonstrates the need for
nitrogen purge within TGA1 to obtain correct hygroscopic moisture values aligned with the Parcher
method.
Table 3 Hygroscopic Moisture, intermediate LOIs’ and final LOI values for a series of RVP samples with
and without a nitrogen purging step for TGA1
The intermediate and final LOI values produced using the automated TGA system were assessed against
a series of internal RTIO standards and external standards provided by Geostats Pty Ltd. The latter were
submitted blindly to the CLB laboratory. Typical LOI values of the standards submitted varied from 511%, which is within the range of expected products to be shipped. The differences between automated
TGA LOI results and certificate values at the various temperatures are shown in Figures 12 to 14 below.
The intermediate and final LOI values obtained using the automated TGA for the various tested samples
agree within ±0.2% of the certified values. RTIO are targeting ±0.15% or better. Towards the end of the
testing period (5th January onwards) a change has occurred in which all LOI’s are reporting higher. This
followed the shutdown of the TGA system for several days due to site experiencing cyclonic weather.
The vendor is currently assessing the reason for this deviation from target as well as the higher
variability in results observed since the shutdown.
Figure 12. LOI differences between TGA2 (425C) and certified values for standards processed between Nov 2013 and Jan 2014
Figure 13. LOI differences between TGA3 (650C) and certified values for standards processed between Nov 2013 and Jan 2014
Figure 14. LOI differences between TGA4 (1000C) and certified values for standards processed between Nov 2013 and Jan 2014
XRF Calibration
Calibration of the Axios XRF was undertaken as required by ISO9516, making a series of
standards produced using pure reagents, and also using XRF Scientific Syncal standard. The calibration
points of the Syncal standards showed significant variation from the line of best fit for the elements
PbO, As2O3, K2O and Cl in this calibration. Figure 15 below shows the PbO calibration line. The Syncal
standards at the low concentration range (0.2%) of the graph are well under the line of best fit (circled
area) when the pure PbO standards (3%) are included in the calibration. Given similar issues with other
elements (Cl, As2O3) reporting low for these Syncal standards, it was decided to remove the Syncal
standards from the calibration and use the pure compound zero points and 3% PbO standards only for
calibration.
0.2% PbO (Syncal
after igniting)
Figure 15 – PbO calibration plot
The K2O calibration however (Figure 16), is dependent only on the results of the Syncal standard, which
appeared to be extremely linear and within specification. Independent standards fused as part of
verifying the calibration showed a maximum of 0.003% higher K2O content then expected using a variety
of standards at approximately 0.010% (approximate shipping grade concentration). However, when
analysis of CRMs containing 2% K2O was performed as part of internal QA QC programs, the calibration
produced values significantly higher than certified target grades by 0.4%. It appears that some losses for
K2O and the elements mentioned above has occurred during preparation of the Syncal standards. The
treatment of the Syncal by ignition at 900°C prior to use was investigated to determine if losses were
occurring at this stage.
Figure 16 – K2O calibration plot
Examination of the Syncal post-ignition treatment showed that the material had changed color
significantly and was more granulated compared with similar treatments previously completed, despite
the same batch of material being treated. At the time of preparing the standard, two separate samples
were ignited in independent furnaces in the event the first sample had been over-heated. Analysis of the
ignited material indicated losses of approximately 9, 14, 40 and 87% for As2O3, K2O, Cl and PbO
respectively. SnO2 losses were also substantial. Loss on ignition tests indicated the substantial mass
losses of 0.7% to 3% (Table 5) when a fresh sample of Syncal was treated at the temperatures of 425°C,
650°C and 1000°C. The TGA curve (Figure 17) shows the losses from the Syncal appear to increase with
temperature and not plateau even at hold times of 50minutes at 1000°C.
Table 5 LOI at various temperatures for Syncal with a hold time of 50mins at 1000°C
Name
SYNCAL
Initial Mass / g
1.6746
Moisture / %
0.32
LOI 425°C / %
0.74
LOI 650°C / %
1.14
LOI 1000°C / %
3.44
Figure 17 XRF Synthetic calibration (070708DB) standard mass loss (green line) with temperature (red line)
Following these findings, internal procedures for preparing the Syncal standard have been modified to
include oven drying the standard at 105°C only for 2hrs. Alternatively the Syncal could be left to
equilibrate and hygroscopic moisture determined to correct to a dry weight basis. XRF calibrations
following the new procedure for drying Syncal have shown improvements in the Syncal results for PbO.
Recent calibration plots for Tom Price are shown in Figure 18 below.
Syncal with
ignition
Figure 18 PbO calibration plot showing improvement in PbO calibration for Syncal at Tom Price
The red circle in Figure 18 shows the lower concentration levels of PbO achieved when the Syncal has
been ignited. The new preparation of Syncal standards shows a PbO concentration that is in agreement
with certified values, and hence falls close to the calibration line when the 3% PbO beads are also
included in the calibration.
At full ship-loading rates, approximately 100-150 samples per day will need to be processed through the
analytical facility. However, during the commissioning phase there were many periods where the HAGHF was available but not required. It was found that following idle periods, when a series of the same
CRM standard was weighed through the same flux dispenser, there was a decreasing trend in the
concentration of SiO2 determined. Figure 19 shows the silica concentration for repeat standard samples
slowly decreased to a consistent concentration from the first disc measured to the last for the original
flux dispenser. The initial two HIY silica concentrations are outside 95% control limits for this CRM. A
replacement dispenser was quickly installed to re-examine this issue. The new flux dispenser shows no
decrease in silica concentration despite the flux residing in the storage container for approximately
12hrs when a similar test is performed (Figure 19). This elevated silica contamination had been
previously detected by another laboratory and was found to be due to the flux residing in the dispenser
for a period of time and silicon from an internal component leaching into the flux. Further testing has
shown normal silica and other element concentration stability when using the new dispenser.
Silica concentration for Yandi standard produced using
old and new dispenser
SiO2 / %s
4.60
Silica Old
Disp
4.50
Silica new
Disp
4.40
4.30
4.20
4.10
HIY1
HIY2
HIY3
HIY4
HIY5
Sample Sequence
Figure 19 RTIO HIY CRM silica concentrations with old and new fusion standards
RTIO has various fusion instruments across its 12 laboratories in the Pilbara. These include Modutemp
TempTron, Initiative Scientific FM-4, Claisse The Ox and now the HAG-HF. Several instruments have
been found to cause Cr and Ni contamination due to the use of these metals in mold and crucible
holders and close proximity to the fusion melt. To confirm there was no cross contamination occurring
in the HAG-HF fusion, a series of high grade and low grade standards were processed through a single
oven unit. Table 6 shows that the Robe Valley standard did not deviate from the expected control limits
despite alternating fusion of the low grade European standard ECRM612-1 (higher in concentration of
trace elements and lower in iron content). These results confirm that there is little to no sample cross
contamination occurring throughout the weighing and fusion process in the HAG-HF. Specifically no
contamination was observed here for Ni and Cr or throughout the evaluation of shift QA/QC samples
during commissioning.
Table 6 Repeatability of high and low grade standards using HAG-HF fusion process
Sample
RVPA/X
ECRM612-1A/X
RVPB/X
ECRM612-1B/X
RVPC/X
ECRM612-1C/X
RVPD/X
ECRM612-1D/X
RVPE/X
ECRM612-1E/X
RVP Actual
RVP Cert
ECRM 612-1 Actual
ECRM612-1 Cert
Fe Calc
55.87
42.41
55.82
42.30
55.86
42.29
55.85
42.40
55.85
42.65
SiO2
6.74
12.68
6.76
12.74
6.73
12.74
6.71
12.68
6.73
12.58
Al2O3
2.95
5.63
2.98
5.62
2.95
5.65
2.96
5.61
2.97
5.58
P
0.037
0.872
0.037
0.872
0.037
0.876
0.039
0.874
0.037
0.864
S
0.015
0.052
0.015
0.053
0.014
0.051
0.014
0.052
0.014
0.052
CaO
0.221
16.648
0.229
16.724
0.226
16.723
0.240
16.674
0.225
16.511
Cr
0.004
0.021
0.004
0.021
0.003
0.021
0.003
0.022
0.003
0.022
Ni
0.000
0.012
0.000
0.013
-0.001
0.012
-0.002
0.013
-0.001
0.011
55.85
55.89
42.41
42.43
6.73
6.69
12.68
12.71
2.96
2.93
5.62
5.67
0.037
0.040
0.872
0.885
0.014
0.015
0.052
0.053
0.228
0.227
16.656
16.874*
0.003
0.002
0.021
0.022
0.000
0.002
0.012
0.014
*CSIRO Division of Minerals achieved 16.63% for this standard during re-certification (Report N1281)
Conclusion and Further Work
As commissioning of the CLB analytical cell continues, upgrade of the control software within the
analytical system is expected to give higher reliability and improved diagnostics of the various
instruments.
The HAG-HF fusion application selected for RTIO was provided by IMP based on the use of the
application from other sites. Given the extreme narrow range of materials to be presented to the HAGHF from the ship-loading system, work will be undertaken to streamline and decrease fusion times. The
HAG-HF has the ability to store numerous fusion programs, hence one-off special samples introduced
(CSIRO SG9 samples) that are found difficult to fuse could be run on longer homogenizing applications
and introduced manually if they are difficult to weigh. The current focus is on maintaining the correct
temperature when new platinum ware is introduced. This is critical given the volatility of some minor
elements.
The automated TGA system installed is a first for RTIO. The system has been shown to be accurate and
reproducible during numerous periods. The introduction of the new alumina oven for moisture analysis
is an improvement which gives very good comparable results to the Parcher method used at RTIO for
the past 10-15 years. Further testwork is required to ensure that the automated TGA can continue to
give accurate and reproducible data for longer periods.
The discovery of losses caused by pre-ignition of the synthetic calibration standard has enabled
improved calibrations for several trace elements such as As2O3, Cl, K2O and PbO. Our internal procedures
have resulted in changes to the preparation of Syncal and a review of the validation standards used to
verify calibrations. The Axios Max at CLB will be extended to provide a calibration for 40mm samples to
enable fused samples from CLA laboratory to be analyzed directly on the CLB XRF in the event of a
breakdown. The CLB XRF has sufficient available capacity to run fused discs delivered from CLA. Both
CLA and CLB share the same LIMS server enabling both laboratories to generate data for samples
produced at either site.
Commissioning of the fully automated analytical facility has been a considerable challenge. Introduction
to Prepmaster software, robot logic and the pressure to achieve early success has been demanding.
Scheduled, organized training and instrument reliability remain the main focus areas to ensure that the
analytical cell continues to deliver reliable and accurate analyses. The input from many professionals at
RTIO/IMP/SKM has been appreciated given the complexity of our analytical requirements and the
flexibility that we demanded from the new instrumentation.