Chapter 13 - Alkali-Activated Cement (AAC) From Fly Ash and High-Magnesium Nickel Slag

Abstract

This chapter reports the potential of the alkali-activation method, also known as geopolymer technology, in converting high-volume industrial waste streams into green cements with significant reduction of energy consumption and CO2 emissions in comparison with the conventional ordinary Portland cement (OPC). A particular case of using fly ash blended with high-magnesium nickel slag (HMNS) as solid materials to manufacture alkali-activated cement (AAC) in laboratory conditions is analyzed in this chapter. By optimizing the dose of alkali activator and the blending quantity of HMNS, it is possible to make a high-strength AAC binder with compressive strength up to 60MPa, which is comparable to OPC and adequate for many construction purposes. The analysis on the carbon emissions and in-body energy indicates that manufacturing the same mass of binder will emit 0.21–0.22t CO2 and require 1.20–1.25GJ for each ton of AAC binder. The slight variation is dependent on the HMNS blending ratio as HMNS has a higher process cost. Alkali-activation method technology is shown to be a highly promising green technology to convert local industrial wastes into useful construction and building materials.