Electric steelmaking process monitoring with optical emission spectroscopy – An in-depth review

Abstract

Electric steelmaking plays an important role in various scenarios for environmentally friendly steelmaking where the processes must be energetically and economically feasible. As electric furnaces’ capacities and low-grade recycled material usage can be expected to increase, optimizing the process practices and flexibility becomes paramount. The high-temperature environment of electric steelmaking sets several criteria for the implemented tools, where the equipment must withstand extreme conditions, have a low maintenance need and cost, and have the capability of real-time data acquisition and analysis. Optical emission spectroscopy (OES) has been studied in laboratory furnaces and on pilot and industrial scales to provide an in situ method for electric arc furnace and ladle furnace process control. Since OES is a method that measures the properties of emitted light, the applications focus on the electric arc plasma, burners’ flames, and heat radiation from the molten bath. The optical spectra carry information on the composition, temperature, and status of the process. This in-depth review compiles the research and usage of OES as a process monitoring tool by focusing on electric arc plasma, burner flames, and molten bath radiation. Suggestions for further development of existing applications and potential new applications are discussed.