Zetium - Analysis of blast furnace using the WROXI wide-range oxides application

Zetium minerals edition Introduction Blast furnace slag is a by-product of the smelting of iron ore to produce iron and steel. It is formed during the fluxing process used to remove the non-ferrous constituents from the blast furnace charge. Slag is an important raw material in its own right, being used extensively in the cement and construction industry. This data sheet demonstrates the performance of the Zetium - Minerals edition XRF spectrometer in providing the accurate and precise analyses of blast furnace slag required by both the iron and steel and cement industries.

Instrumentation The Minerals edition of the Zetium spectrometer is a fully integrated wavelength dispersive XRF spectrometer, complete with X-Y sample handler and state-of-the-art software. Engineered for excellence in terms of both analytical and operational performance, it has been configured specifically to meet the needs of users in the mining and minerals industries.

The Minerals edition of the Zetium spectrometer can be delivered with a set of 19 synthetic multi-element wide- range oxides (WROXI) standards and an application template for the analysis of major and minor oxides in fused beads. Using PANalytical’s unique FP algorithm in our SuperQ analytical software, the WROXI application can determine concentrations of up to 21 common oxides in a wide range of rocks, ores and minerals. WROXI can be used either as a primary fused bead calibration or to verify customer in-house standards for pressed powder applications.

Sample preparation and measurement details Nine certified reference materials (CRMs), including some of the BCS-, ECRM- and JSS- series of standards, were prepared and analyzed as routine samples to test the accuracy of the WROXI calibrations. The WROXI standards and CRMs used in this study were prepared using 0.9 g of sample fused in 9.0 g flux (66 % lithium tetraborate, 34 % lithium metaborate) and cast into 40 mm diameter fused beads. The measurement program used to obtain the data presented had a total measurement time of nine minutes (Table 1). The time can, however, be adjusted according to the required precision.

Table 1. Total measurement time (peak + background)

Accuracy The accuracy achieved with the Zetium spectrometer using WROXI standards and the SuperQ (FP) calibration model for major and minor element analyses in blast furnace slags is very good. This is illustrated in Figure 1 for CaO, SiO2 and MgO where measured values are compared to certified values. A further comparison of 11 oxides in a single slag CRM (ECRM879-1) is provided in Table 2. Loss on ignition (LOI) is accurately determined as a balance compound by the SuperQ FP algorithm.

Table 2. A comparison of certified and measured concentrations for a basic slag CRM ECRM879-1

Precision The precision, repeatability and reproducibility of the Zetium spectrometer are excellent, not only in the short term, but also for measurements carried out over a longer period of 14 days (Table 3). The data presented did not require any form of drift correction. For comparison, the counting statistical error (CSE) expressed in concentration units is also shown in Table 3. The CSE is theoretically the minimum possible error and the data demonstrates the inherent stability of the Zetium spectrometer.

Table 3. Reproducibility (10 measurements over 14 days) for blast furnace slag (BCS 367)

Conclusion Elemental analysis with XRF is already a key analytical technique for controlling production processes in the iron, steel and cement industries. The Minerals edition of the Zetium spectrometer with WROXI and the SuperQ FP approach further extends the advantages of XRF as the best analytical method for reliable blast furnace slag analysis. It has been demonstrated that analyses are accurate and precise and the method benefits from a simple fusion sample preparation. Furthermore, the stability of the system is such that individual calibrations can be used for months and require minimal maintenance. Time-consuming recalibrations are unnecessary and the resultant data are highly consistent over time.

Zetium - Analysis of blast furnace using the WROXI wide-range oxides application

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