Review of comprehensive utilization of typical ferroalloy slags

Three typical ferroalloy slags, namely, silicon–manganese, nickel–iron, and chrome–iron slags, are produced in large quantities as by-products. This is because they are not efficiently utilized, which creates lots of pressure on environmental capacity and development of enterprises. At present, comprehensive utilization of ferroalloy slags is mainly concentrated on the traditional building materials such as cement and concrete. Although the construction industry consumes a large amount of ferroalloy slags, their high-energy consumption and relatively limited product value limit their maximum utilization. With the increasing market demand and improvement of energy and environmental awareness, the research on rational utilization of ferroalloy slags has been changing from its use as raw materials in traditional building materials to use as raw materials to produce new products with comparatively lower energy consumption and higher product value, which explores the possibility of slag reutilization in other fields. Based on the quality requirements of different ferroalloys, there are significant differences in the requirements of the raw materials and different smelting processes. As a result, different types of ferroalloy slags, having different physical and chemical properties, are produced. This study briefly presented the uses of the silicon–manganese, nickel–iron, and chrome–iron slags. It also showed how to classify these three typical ferroalloy slags. The differences of their chemical and mineral phase composition were also systematically analyzed in this study, which discussed different properties of different slags and provided the basic theoretical guidelines on how to efficiently utilize these slags. This study also emphatically summarized the latest domestic and foreign research advancements about their utilization in traditional building materials such as cement and concrete, and in new functional materials such as geopolymer, inorganic mineral fiber, microcrystalline glass, artificial light aggregate, and refractory materials required to build walls and as alternative raw materials to prepare functional ceramics. Based on the results of this study, we summarized the advantages and disadvantages of using the abovementioned ferroalloy slags as raw materials to generate different materials, and put forward the prospects for its future utilization direction and approach. The study also guided the key development areas for further studying and breaking through the bottleneck of the main utilization mode, formulating and improving the relevant application and pollution control standards, and developing and promoting high value-added products.