Synergistic preparation of geopolymer using electrolytic manganese residue, coal slag and granulated blast furnace slag

Abstract

To improve the utilization rate of industrial solid waste and the sustainable development of geopolymer research and development, this article uses electrolytic manganese residue (EMR), coal slag (CS), and granulated blast furnace slag (GGBS) as raw materials to prepare a new eco-friendly geopolymer cementitious material (GOCM). The mechanical properties, phase composition, and microstructure of GOCM are measured and analyzed using methods such as compressive bending strength test, X-ray diffraction, scanning electron microscopy, mercury intrusion test, and Fourier transform infrared spectroscopy. The effects of material ratio, water cement ratio, and alkali activator content on GOCM are explored. Meantime, the environmental characteristics of GOCM were also investigated through toxicity leaching experiments. Results show that CS improves the flowability and late compressive strength of GOCM, and EMR reduces the setting time of the slurry, the maximum strength of GOCM was observed when the contents of EMR, CS, and GGBS were 25 %, 55 %, and 20 %, the mass fraction of alkaline activator was 14 %, and the W/C was 0.45. and the maximum compressive strength reaches 22.8 MPa. The hydrates in GOCM are composed of flocculent, cluster, block C–S–H gel. The hydrates formed have excellent stabilization effect on heavy metals in raw materials. When the GOCM material ratio is optimal (the contents of EMR, CS, and GGBS were 25 %, 55 %, and 20 %), the leaching concentration of Cd, Cr, and Mn is lower than the limit values (Cd < 0.001 mg/L, Cr < 0.01 mg/L, Mn < 0.05 mg/L) specified in GB/T14848-2017.