The properties and mechanism of microbial mineralized steel slag bricks

• Preparation of microbial mineralized steel slag bricks is at room temperature, gas pressure is just 0.3 MPa, no molding pressure.
• Calcium carbonate is the gelled product through microbial mineralization.
• Utilize the industrial waste steel slag and absorb the industrial carbon dioxide.

An experimental program was carried out to investigate the possibility of producing microbial mineralized steel slag bricks through mineralization. The properties of different steel slag bricks such as strength and carbon uptake were mainly investigated. Mineralization could significantly improve the strength, the optimal SL/SS ratio for the microbial mineralized steel slag bricks is 0.3. Through 3-h mineralization after demoulded, the highest compressive strength of the steel slag bricks can up to 17.1 MPa, flexural strength up to 4.22 MPa. Through X-ray diffraction (XRD), mercury-intrusion porosimetry (MIP), scanning electron microscopy (SEM), and differential thermal and thermogravimetric analysis (DTA/TG), the mechanism of the microbial mineralized steel slag bricks was analyzed and discussed.