Lithium in Portland cement clinker: absence of evidence is not evidence of absence

Lithium (Li) is a challenging element to analyse in mineral matrixes. The very low energy (54 eV) of its X-ray emission line makes it almost impossible to analyse by common methods such as energy dispersive spectroscopy. Hence, its localisation within cementitious phases is poorly known. Based on glow-discharge mass spectrometry and time-of-flight secondary ion mass spectrometry, the present paper shows for the first time the repartition of Li at the scale of a microstructure of clinker with a 200 nm lateral resolution. Li is correlated to both Al and Fe in the interstitial phase, but also to Mg in periclase.