Abstract: This paper provides a systematic overview of the magnetic separation process for steel slag. Starting from the elemental and mineral composition of steel slag, it discusses the important role played by mineralogy in the techno-economic feasibility of magnetic separation of steel slag. The research developments in magnetic separation of steel slag are summarized in terms of unit operation, equipment innovation, process optimization, pre-treatment, and integration with other sorting techniques, along with references containing detailed parameters. Finally, a brief clarification is given on the often-confused units of magnetic field strength and magnetic induction in magnetic separation of steel slag .