Reaction of electric arc furnace dust with molten iron containing carbon

The remelting of steel scrap, in particular automobile scrap, in an electric arc furnace results in the production of a fine and highly contaminated zinc-rich dust which is known as electric arc furnace dust. A number of processes have been developed to recover the valuable metals from the dust, but there has been only limited commercial success. The majority of the processes tested have been pyrometallurgical or hydrometallurgical or hybrids. In the present research, the reaction of the dust with molten pig iron containing carbon was investigated as a possible treatment method. The effects of processing time, temperature, electric arc furnace dust to pig iron ratio and the carbon concentration of the pig iron on the process are discussed. The sample mass loss and the zinc, the iron and the lead contents of the reacted slag were determined. Almost 100% of the zinc was readily reduced from the dust. On the other hand, although the majority of the iron could be recovered, it was difficult to reduce the residual iron oxide in the slag. The iron was recovered in the pig iron and the zinc was recovered as a relatively pure zinc oxide (99%ZnO). Based on both the thermodynamic analysis and the experimental results, a reaction mechanism is proposed for the process.