Abstract: Steel slag is a by-product of the steelmaking process and grinding it into ultra-fine micropowder can improve its chemical activity, facilitating resource utilization. This paper analyzes the existing problems in common steel slag grinding systems including vertical mill final grinding, roller press final grinding and ball mill grinding, and proposes a solution by developing TRMGP34.2 external circulation steel slag vertical mill combined grinding system. Taking a production line with an annual output of 300 000 tons of ultra-fine steel slag powder as an example, the process flow, main equipment configuration, working principle and key features of TRMGP34.2 external circulation steel slag vertical mill are introduced. Key parameters such as grinding table speed and roller pressure were optimized, and the designs of grinding zone, scraping plate, slag discharge port, wear-resistant lining plates and internal iron removal device are inproved. After the project was put into operation, it further optimized the grinding pressure of the nill, improved the vibration of the mill, adjusted the amount of water spraying in the mill, the outlet wind temperature and the circulation of the external slag discharge,,so that the ultra-fine steel slag powder with product specific surface area reaches 550m2/kg, and the production is continuous and stable, which effectively promotes the resource utilization of steel slag.
