Mechanism and Assessment of the Pozzolanic Activity of Melting-Quenching Lithium Slag Modified with Mgo

•The possibility of incorporation of MgO as chemical modifier for the pozzolanic activity of LS.•Confirmation of pozzolanic behavior of MGLS attested to by the FTIR NMR results for the transformation mechanism of coordination structure.•New cemented pastes designed with Portland pozzolana cement (PPC) and MGLS from the mechanical point of view.•The additional products formed as a result of the pozzolanic reaction can enhance the unconfined compressive strength (UCS) of cemented pastes based on the incorporation of MGLS.