Properties and microstructure of blended cement containing activated iron tailings powder

To solve the hidden safety brought by iron tailings powder (ITP). The preparation of green binding materials through ITP have shown bright prospects. However, low activity limits the use of ITP as a supplementary cementitious material in large amounts. Therefore, the activity of ITP at different milling times and sintering temperatures, and its effect on the properties and microstructure of blended cement were studied. The results revealed that ITP has a filling effect and provides additional nucleation sites. In addition, ITP exhibits pozzolanic activity in the later stage, and consumes more hydration products CH, which promotes the formation and deposition of C-S-H, which are all related to its specific surface area. These also provide the conditions for cement paste densification, and lay a foundation for blended cement strength. Moreover, the environmental impact and cost of plain cement were higher than those of mixed cement. Highlights The activity of activated ITP is related to its specific surface area. ITP has a filling effect and provides additional nucleation sites. It takes a long time for iron tailings powder to exert pozzolanic activity. The activated ITP undergoes a secondary reaction to form a hydration product. The environmental impact and cost of pure cement were higher than mixed cement.