Research progress on the application of steel slag for soil remediation

Steel slag is a by-product of the steel industry. A large amount of untreated steel slag waste is piled up, which not only seriously wastes resources but also occupies a large amount of land resources, thus causing pollution to the surrounding soil and environment, and even posing a major threat to human production and life. At present, the production of steel slag in China is increasing rapidly, but the comprehensive utilization rate of steel slag is only about 20%. Using steel slag for soil remediation is one of the important directions for combining solid waste disposal with ecological construction. Based on summarizing the physical and chemical properties of steel slag resources, the basic principles and status quo of using steel slag for soil remediation at home and abroad were summarized. The main functions of steel slag as a soil conditioner, soil fertilizer, and soil heavy metal passivator were systematically analyzed. Steel slag, as a soil conditioner, could not only improve acid soil but also effectively reduce greenhouse gas emissions. As a soil fertilizer, it could provide trace elements and nutrients for the soil, and as a soil heavy metal passivator, it could reduce the heavy metal content in soil. The potential of steel slag for soil remediation was pointed out, and the environmental impacts produced by steel slag used in agricultural soil were explored and the risk assessment was conducted. Finally, the future research direction for the application of steel slag in soil remediation was discussed.