Properties of low sulfur leached spodumene as supplementary cementitious material in ordinary Portland cement

Abstract

In the context of the increasing demand for lithium, the extraction of lithium from spodumene is being pursued. During the processing of spodumene, large quantities of leached spodumene concentrate (LSC) are produced as a by-product. To avoid the deposition of the material, potential reuse of the material within the cement industry is investigated. XRD and XRF analyses show that the LSC consists predominantly of leached spodumene and thus of an Al2O3 and SiO2 containing material. The pozzolanic composition of the material suggests a reusability of the material as supplementary cementitious material (SCM) within the cement industry. To test this approach, the hydration properties of LSC powders in combination with OPC cement are investigated. The chemical and mineralogical composition was determined using X-ray methods, followed by the assessment of the hydration behavior of LSC by puzzolanity testing and calorimeter of the heat flow. The tests show that a low-sulfur LSC (up to 1.8 %) is very reactive for mixtures of up to 20 % and produces high mechanical strengths in combination with an OPC. The influence of different raw material sources and process-related fluctuations on the conversion rate from α to β spodumene is negligible.