Effects of TEA on rheological property and hydration performance of lithium slag-cement composite binder

Effects of triethanolamine (TEA) on rheological property and hydration performance of lithium slag (LS) composite binder were analyzed. The rheological property was characterized via the parameters of viscosity and yield stress measured by rheometer. Hydration process was studied through hydration heat via hydration calorimeter, hydrates trait was investigated by X-ray diffractometer (XRD), differential scanning calorimeter (DSC) as well as thermogravimetry (TG), pore structure was measured via mip mercury pressure (MIP), and microstructure as well as morphology of hydrated matrix was analyzed via scanning electron microscope (SEM) equiped with energy dispersive X-ray spectroscopy (EDX). Results showed that influence of TEA on hydration of LS composite binder was highly correlated with its content. Proper amount of TEA (0.06%-0.08%) enhanced the dissolution of Si4+ and Al3+ ions from LS minerals, contributing to promoted pozzolanic reaction of LS to produce higher amount of hydration products, resulting in denser microstructure of hardened matrix with refined pore structure with less macro-pores and more gel pores, which led to increased mechanical strength of LS-cement mortar. Moreover, the promoted dissolution of Si4+ and Al3+ ions from LS led to decreased Ca/Si and Ca/(Si + Al) atom ratios as well as increasd Al/Si atom ratio in hydration products. However, excessive amount of TEA (0.1%-0.2%) significantly delayed the hydration process of LS composite binder and impaired growth trend of the early mechanical performance of LS composite binder.

Automated summary

The effects of triethanolamine (TEA) on the rheological properties and hydration performance of lithium slag (LS) composite binder were examined. Proper amounts of TEA enhanced dissolution of Si4+ and Al3+ ions, promoting pozzolanic reactions and resulting in denser microstructure and increased mechanical strength, while excessive amounts delayed the hydration process and impaired early mechanical performance.