Progress in treating difficult-to-handle dust and sludge and full-scale resource utilization in an iron and steel industry cluster

Iron and steel metallurgical dust is a solid waste produced in the production process of the iron and steel industry. It has the characteristics of many types, large quantities, complex components, and many valuable elements. Japan and Germany have realized the centralized treatment and comprehensive utilization of metallurgical solid wastes, and China’s current technological level is still far behind them. This paper briefly described the existing treatment processes of iron and steel metallurgical dust and mud and specifically introduced the most widely used pyrotechnic processes in enterprises, including the rotary kiln, Oxycup, and rotary hearth furnace processes. The current treatment process of iron and steel metallurgical dust and sludge mainly stays in the first three stages of dust and sludge resource recycling and often only separates and recovers some elements with high contents. In addition to elements such as Fe, Zn, Pb, K, and Na, dust and mud in an iron and steel industry agglomeration area are also enriched with large amounts of valuable and rare elements with high added values such as In, Bi, Sn, and Cd, which are precious materials. The ineffective treatment and recycling of a huge volume of iron and steel metallurgical dust and mud will cause serious air, water, and soil pollutions; affect the ecological environment; and endanger human life. Moreover, it will cause a considerable loss of valuable resources, which is not conducive to the rapid development of China’s industries. With the requirements of the national environmental protection regulations and industrial policies, steel metallurgical dust and sludge have reached a new stage where 100% of all dust and sludge must be recycled. In response to this, a technical solution established on the product design based on the coordination of various types of dust and mud, scientific coupling, and system integration among unit technologies was proposed according to their respective composition characteristics to achieve multicomponent cascade separation and full utilization. The full resource utilization of metallurgical dust and sludge in iron and steel enterprises provides a reference.