Sustainable utilization of lithium slag through chemical activation: Development of low-carbon cementitious materials...

This study investigated the sustainable utilization of lithium slag through chemical activation with diethanolisopropanolamine (DEIPA), aiming to develop low-carbon cementitious materials based on a cement-lithium slag-limestone ternary blend. By evaluating compressive strength, hydration heat evolution, hydration products, and microstructural evolution, the effects of DEIPA on the hydration kinetics and microstructure development of the ternary blend were systematically investigated. The results indicated that DEIPA exhibited a pronounced dosage-dependent effect on the hydration process and mechanical properties of the ternary blend. Specifically, 0.04% DEIPA promoted the hydration of the silicate phase and ferrite, thereby increasing the formation of C-S(A)-H gel and hemicarbonate (Hc), resulting in a 47.40% increase in 3 d compressive strength. It is worth noting that the Si/Ca ratio of the C-S(A)-H gel increased with higher DEIPA dosage, and the early age morphologies transitioned from clustered to plate-like structures. Conversely, a higher dosage of 0.08% inhibited silicate hydration, thereby reducing the formation of C-S(A)-H gel and causing a 13.19% decrease in 3 d compressive strength. In the later stage of hydration, DEIPA continued to facilitate the hydration of silicate phases and ferrite, as well as the pozzolanic reaction of lithium slag and the chemical effect of limestone, thereby inducing the formation of a multiphase interwoven structure composed C-S(A)-H gel, ettringite (AFt), and monocarboaluminate (Mc), which refined the pore structure of the hardened paste and enhanced its compressive strength. This study explores the effects of DEIPA on the hydration properties of the cement-lithium slag-limestone ternary blend and provides theoretical guidance for the wider application of lithium slag in cement-based materials.