Investigation on sulfate activation of electrolytic manganese residue on early activity of blast furnace slag in cement-based cementitious material

Clinker, blast furnace slag (BFS) and electrolytic manganese residue (EMR) were used to make the cement-based cementitious material (CCM) in this research. The activation effect of EMR with different content on the early activity of BFS was studied. The mechanical properties were analyzed by cement mortar test. The hydration characteristics were investigated by XRD, SEM, Si-29 NMR and other micro-analysis methods. The results indicate that the early strength of CCM can be greatly improved when the content of EMR is 15%. The microscopic analysis of XRD, SEM and Si-29 NMR show that the secondary hydration reaction of BFS was accelerated by the sulfate, and more BFS was depolymerized, which resulted in a significant increase in ettringite (AFt) and C-S-H gel production at 3d. Meanwhile, the consumption of Ca(OH)(2) increases. The pore diameter becomes smaller and the structure is more compact. Leaching test results show that NH3-N and heavy metals are well solidified in the cementitious material, which shows a good environmental performance. This research provides an effective path for the disposal of EMR and sulfate activating to pozzolanic materials. (C) 2019 Elsevier Ltd. All rights reserved.