In the heart of Beijing, researchers at the University of Science and Technology Beijing are tackling one of the steel industry’s most pressing challenges: what to do with the mountains of steel slag produced during the steelmaking process. Led by Xin Liu, a team from the State Key Laboratory of Advanced Metallurgy is exploring innovative ways to turn this waste into a valuable resource, with significant implications for the energy sector.
Steel slag, a byproduct of steel production, has long been a headache for the industry. With only 30% of it being reused, the rest ends up in landfills, causing environmental damage and wasting valuable resources. Liu and his team are focusing on one of the main obstacles to recycling steel slag: phosphorus. This nonrenewable resource, vital for agriculture and industry, accumulates in steel slag, making it difficult to reuse.
“The optimal utilization of steel slag lies in reusing it in the steelmaking process,” Liu explains. “However, the lack of a suitable phosphorus outflow pathway hinders this process.” The team’s research, published in the Journal of Engineering Sciences, delves into the sources and properties of steel slag, the current state of its treatment and utilization, and the technologies for phosphorus enrichment and separation.
One of the most promising methods they’ve identified is the carbon thermal reduction process. This technique has shown a high degree of removal efficiency for phosphorus, opening up the possibility of a more sustainable steelmaking process. By extracting phosphorus from steel slag, it can be used in the phosphorus chemical industry, while the remaining tailings can be reused in metallurgical plants.
The potential commercial impacts are substantial. If steel enterprises can increase the comprehensive utilization rate of steel slag, they could significantly reduce environmental pollution and resource waste. Moreover, the tailings from the phosphorus extraction process can be returned to the converter for reuse as steelmaking or sintering flux, making full use of the sensible heat present in the slag.
Liu and his team are proposing a full recycling technology for steel slag based on carbon thermal reduction dephosphorization. During the pouring process of hot steel slag, phosphorus can be separated under suitable process conditions, achieving a dephosphorization rate of 79.25%. This new steel slag treatment process and hot-state full utilization technology could pave the way for a greener metallurgical industry.
The research also highlights the need for a novel approach to steel slag treatment that aligns with China’s laws, policies, and standards. While foreign developed countries have their own methods, China’s massive steel slag production and stock require a unique solution.
As the world grapples with the challenges of sustainability and resource scarcity, innovations like these are crucial. They not only address immediate environmental concerns but also pave the way for a more circular economy, where waste is minimized, and resources are maximized. The work of Liu and his team, published in the Journal of Engineering Sciences (工程科学学报), is a testament to the power of scientific research in driving industrial progress and environmental stewardship. As the steel industry looks to the future, the insights from this research could shape the development of more sustainable and efficient steelmaking processes, benefiting both the industry and the planet.
