Using Eutectic Flux to Fuse Ferrous Ore

Precisely analysing the elemental composition of ferrous ores is critical to a range of earth exploration, metalworking, and mine mapping applications. Generally, the term ferrous is used to describe any metal containing an appreciable amount of iron per weight percentage (wt%), but its chemical designation is defined as metallic compounds containing iron(II) oxide—which is iron in the +2 oxidation state.

Chemists play a key role in winning valuable ores by helping to predict the location and relative abundance of deposits, and qualifying subsequent deposits via low-level elemental analysis. This latter process is where eutectic flux chemicals enter the metallurgical workflow.

Extracting, Treating & Analysing Iron

Iron is derived from a range of ferritic compounds which are normally defined by concentration. The following percentiles indicate the average concentration of iron in each respective compound: magnetite (72.4%), hematite (69.9%), goethite (62.9%), limonite (55%), and siderite (48.2%). Natural ores with more than 60% concentration of iron can be used directly in blast furnaces for the production of pig iron, but these so-called direct-shipping ores (DSOs) are far les abundant than more complex formations with lower concentrations.

Secondary iron formations are typically metamorphosed with other minerals, forming carbonates, silicates, oxides, and so on. Extracting iron from this mineralogical matrix and treating it prior to elemental analysis is a key intermediary step in determining the potential value of a newly discovered deposit—as well as providing insights to a range of related applications. Accessing the composition of iron ore at the sub-parts per million (ppm) level can be extremely valuable to chemists, project managers, and more.

X-ray fluorescence (XRF) spectroscopy is the technology of choice for analysing the trace-level composition of ferrous ores, but their complex matrices must first be deconstructed through intensive heat treatment. X-ray flux chemicals known as eutectic fluxes are often used to stabilise molten mixtures and protect labware from chemical attack by molecules within the sample. Owing to the likely presence of acidic oxides or alumino-silicates in iron ore samples, it is important to use a eutectic flux with a comparatively low melting temperature, otherwise the flux formula may fail to preserve labware leading to probably failure and sample contamination. Additionally, oxidising chemicals like sodium or lithium nitrate are often incorporated with the flux chemicals to maximise labware protection.

Eutectic Fluxes from XRF Scientific

At XRF Scientific, we supply a novel eutectic flux comprising two lithium borate salts at a ratio of 12:22 lithium tetraborate to lithium metaborate. This yields a melting range of 825—925°C, which is ideal for decomposing the complex mineralogical structure of ferrous ore without moderating its chemical composition. This means our eutectic mixture enables chemists to gain a truly homogenous representation of the ppm-level iron concentration of ferrous samples with ease. Interested in purchasing X-ray flux chemicals? Contact a member of the XRF Scientific team today.