In the quest for sustainable and low-carbon building materials, a groundbreaking study led by Jianshuai Hao from Chang’an University and China University of Mining and Technology-Beijing has unveiled the intricate dance of chemical reactions that could revolutionize the mining and construction industries. Published in the *International Journal of Mining Science and Technology* (known in English as the *Journal of Mining and Metallurgical Engineering*), this research delves into the synergistic mechanisms of steel slag, granulated blast furnace slag, and desulfurization gypsum in high-content steel slag-based cementitious backfill materials.
Steel slag, a byproduct of steel production, has long been an environmental challenge due to its sheer volume and potential hazards if not managed properly. However, Hao and his team have discovered a way to turn this liability into an asset. “By understanding the hydration process and the synergistic effects between steel slag, granulated blast furnace slag, and desulfurization gypsum, we can optimize the performance of cementitious materials used in mine backfilling and construction,” Hao explains. This optimization not only enhances the material’s strength and durability but also significantly reduces the carbon footprint of construction projects.
The study reveals that granulated blast furnace slag (GBFS) plays a pivotal role in this chemical symphony. By releasing active silicon and aluminum ions, GBFS triggers a synergistic activation effect with calcium ions from steel slag, promoting the formation of C-S-H gel and ettringite. These compounds are crucial for the microstructure of the hardened paste, making it stronger and more resilient. “When the GBFS content reaches 30%, the C-S-H content increases by 40.8%, and the pore size distribution improves dramatically,” Hao notes. This leads to a 68.7% reduction in large pores and a fivefold increase in 90-day compressive strength compared to the baseline group.
Desulfurization gypsum (DG) also plays a significant role in this process. It accelerates the hydration of silicate minerals, but the study warns that excessive incorporation can lead to microcracks due to the expansion of AFt crystals, resulting in strength reduction. “Under the synergistic effect of 8% DG and 30% GBFS, the hydration reaction is most intense, with the peak heat release rate reaching 0.92 mW/g and the cumulative heat release amount being 240 J/g,” Hao explains.
The research constructs a “steel slag-GBFS-DG-cement” quaternary synergistic system, optimizing the matching of active components in high-content steel slag systems. This innovation significantly improves microstructural defects and meets engineering application requirements, providing a theoretical basis for the component design and performance regulation of high-content steel slag-based cementitious materials.
The implications of this research are far-reaching. For the mining industry, it offers a sustainable solution for managing steel slag, reducing waste, and lowering environmental impact. For the construction sector, it paves the way for low-carbon building materials that are stronger and more durable. “This study not only advances our understanding of the hydration process but also opens up new possibilities for the application of steel slag in various industries,” Hao concludes.
As the world grapples with the challenges of climate change and resource depletion, this research offers a beacon of hope. By turning industrial waste into valuable construction materials, it exemplifies the circular economy in action. The findings published in the *Journal of Mining and Metallurgical Engineering* are set to shape future developments in the field, driving innovation and sustainability in the energy and construction sectors.