The Influence of Microbial Agent on the Mineralization Rate of Steel Slag

Abstract

Bacteria‐based mineralization is a new technique to use the steel slag. In this article, an experimental examination was performed to find out the steel slag advancement by the addition of the microbial agent that has the possibility to accelerate mineralization ability of bacteria. It is observed that, under natural and CO2 pressure curing conditions, the carbonation rate is significantly raised when microorganisms are added to the steel slag. The increased ratio of microorganisms leads to a better carbonation rate. The reaction products formed by bacteria mineralization were analyzed with the scanning electron microscope (SEM) and X‐ray diffraction (XRD), and the amount of reaction products was examined by thermogravimetric analysis. The results show that the compressive strength and carbonation speed rose with the increase in microorganism content. Bacterial could accelerate the rate of carbon sequestration in the mineralization process. The compressive strength of steel slag with 1.5% bacterial could reach up to 51.5 MPa. The micron‐sized and roughness mineralization product induced by microorganisms apparently resulted in a denser and compacted structure. The carbon depth increased by 50%, and the content of calcite increased by 3 times. These mineralization products would fill in the pore of steel slag cementitious materials and form the integrated and denser structure which produces more strength.