Abstract

Significance The choice of primary treatment technology for steel slag has a significant impact on its subsequent processing and utilization. This paper briefly outlines the primary treatment technologies and comprehensive utilization methods for steel slag， providing a review of their working principles， advantages， and disadvantages. Technologies such as the hot-braising process， rotating drum process， and hot-pouring process are discussed. Given the current state of steel slag utilization， this paper also summarizes the challenges restricting its application and proposes improvement technologies and strategies for steel slag recycling.

Progress When selecting primary treatment methods， multiple factors should be considered， including its potential uses， energy conservation， environmental impacts， and economic benefits. The diverse applications of the primary treatment technologies for steel slag in major steel mills worldwide result from the differences in steelmaking equipment， processes， the physicochemical properties of the slag， and its utilization in later stages. In China， steel slag is primarily used in metallurgical industry， particularly for iron beneficiation. After hot steel slag undergoes primary treatment and multi-stage crushing， magnetic separation is used to recover slag steel from the steel slag for steelmaking， recover magnetic separation powder for sintering， and tailings for building material utilization. As a result of the increasing scarcity of river sand due to mining restrictions， steel slag as building materials in construction is expected to increase， which could help address the large stockpiles of steel slag.

Conclusions and Prospects China faces large production quantities but low utilization rates for steel slag with large amounts stored in open piles， occupying land and posing environmental risks such as heavy metal leaching. Although steel slag has been used in various sectors， including construction， agriculture， wastewater treatment， and ceramics， it remains largely underutilized in large-scale， high-value applications. Maximizing the use of steel slag can reduce China's dependence on natural resources， reduce solid waste pressures， and mitigate carbon emissions， thus advancing the sustainable development in steel industry. Despite progress in steel slag research， comprehensive utilization of steel slag is hindered by the rising production rates and insufficient technological improvements， leading to annual declines in its utilization rate. Furthermore， the lack of large-scale industrialization and high-value applications remains a crucial concern. In the future， it is essential to focus on the recovery and utilization of sensible heat of molten steel slag， which is key to addressing the technological challenges and advancing the steel industry towards greener and more sustainable operations. Steel slag applications have expanded beyond traditional landfills to cement production and construction materials. Nevertheless， an effective strategy for large-scale recycling remains a challenge. Therefore， developing efficient， diversified primary treatment technologies and enhancing comprehensive utilization represent key issues in iron and steel metallurgy. This progress will provide a solid foundation for China’s green industrial development.

Keywords： steel slag； primary treatment technology； comprehensive utilization； hot-braising process； rotating drum process； hot-pouring process