Recently, the Full-process Steel Slag Dry Treatment and Efficient Waste Heat Recovery Project of a steel enterprise, undertaken by Capital Engineering & Research Incorporation Limited (hereinafter "CERI") as the EPC Contractor, was successfully put into full operation. The Project is the first to implement the full-process steel slag dry treatment and efficient waste heat recovery technology jointly developed by CERI and Beijing Tanlong Environmental Technology Co., Ltd. (hereinafter "Beijing Tanlong"). 

Leveraging methods such as air jet heat extraction, moving-bed dry rolling granulation, and annular grate air-cooling heat exchange, this technology enables dry cooling and granulation of steel slag while maximizing waste heat recovery. The system delivers an average steam output of approximately 7.5 t/h, with a peak of 8.5 t/h, with each ton of slag yielding around 300 kg of steam (1.2 MPa superheated steam). The process comprises two core stages: the primary stage of moving-bed dry granulation and heat extraction, and the secondary stage of crushing and magnetic separation. 

In the primary stage of moving-bed dry granulation and heat extraction, steel slag is granulated, and heat is extracted using a jet heat extraction system installed in the enclosed rolling granulation hood. The high-velocity air stream generated by the jet system penetrates the steel slag layer, ensuring thorough contact and significantly enhancing heat transfer efficiency. Molten steel slag at approximately 1400°C can be solidified, granulated, and cooled to around 700°C within 40 minutes. Subsequently, with the integration of an annular grate air-cooling heat exchanger, the slag temperature is further reduced to below 150°C before entering the secondary crushing and magnetic separation stage. During the above steel slag cooling and granulation process, the jet air in the rolling granulation hood and the heat exchange air in the annular grate air-cooling heat exchanger are heated after absorbing heat from the steel slag. This heated air is then directed to the waste heat boiler for steam generation and utilization. Afterwards, the exhaust gas is recirculated by the circulating fan back to the rolling granulation hood and annular grate air-cooling heat exchanger, achieving efficient heat recovery. 

The secondary crushing and magnetic separation stage involves the utilization of belt conveyors, jaw crushers, rod mills, magnetic separators, and other equipment to crush, grind, and magnetically separate steel slag that has undergone primary treatment. This enables effective separation of slag and iron and efficient recovery of valuable metallic iron, greatly enhancing resource utilization in steel enterprises. 

The Project marks this technology's world-first large-scale industrial application, realizing recovery and efficient utilization of waste heat across the full temperature range of steel slag treatment. By integrating resource recovery into the secondary crushing and magnetic separation process, the technology enables truly efficient and comprehensive recovery and utilization of steel slag resources and energy. The successful engineering application of this technology marks the resolution of the global challenge of efficient waste heat recovery from molten steel slag, providing a scalable circular economy solution that allows the iron and steel industry to maximize energy efficiency and achieve zero solid waste discharge.