제강분진 공정부산물 DRI(Direct Reduction Iron)로부터 아연 및 선철 회수 연구

Abstract

About 10-20kg dust is generated per ton of steel produced during the electric furnace steelmaking process As of 2020, Korea's annual production of crude steel is estimated to be about 20 million tons, so the amount of dust generated is estimated to be more than 300,000 tons, of which zinc content is about 25%, and about 100,000 tons of zinc is generated in the form of dust per year. This is called steel dust, and the steel dust contains heavy metals such as zinc, iron, lead, manganese, copper, and cadmium, as well as anions such as chlorine and fluorine.Zinc is distilled in a gas phase using Rotary Reduction Kiln (Waelz Kiln) to obtain zinc oxide. In the process of producing zinc crude oxide from steel dust, zinc is volatilized and recovered from the filter, and residue remains inside the kiln. It contains flux components added to prevent ring formation, zinc that has not yet been volatilized, solid iron, etc., and is recovered in the form of a clinker. The process waste without separate treatment processes to do so, this is a waste, steel dust treatment processes and treated as fill material mixture of materials, cement or construction, road paving materials used to. The by-products of the processing process of steelmaking contain about 5-9 wt.% of Zn and about 50-60 wt.% of Fe, which are mostly treated depending on landfill due to the absence of treatment technology and social interest. In addition to the cost of landfill treatment, problems of surrounding soil pollution and water pollution by landfill arise, and because it contains a large amount of iron and zinc, a large amount of economic loss occurs due to simple landfill without extracting valuable metals. Therefore, it is necessary to develop recycling technology for waste treated by landfill. Therefore, in this study, zinc powder and iron were manufactured through a dry process of DRI, a by-product of the process collected in the zinc oxide manufacturing process from steel dust. The high-purity zinc powder recovery process was a vapor distillation method for recovering Zn by mixing DRI and carbon powder, and the vapor distillation process was maintained at 1000°C for 4 hours at a weight ratio of DRI : carbon powder = 10:1. Zn deposited in the recovery tube was recovered at room temperature. After recovery, iron is produced through a reduction melting reaction from the residue. The pig iron manufacturing process was maintained at DRI : carbon powder = 10:3, flux composition (Cao : Sio2) = 1:1, and reaction temperature at 1600°C for 30 minutes. The slag was separated in the crucible and Fe was recovered. Finally, through the above process, the spherical Zn powder of 99.8% zinc and 91.59% recovery rate were recovered, and the pig iron was recovered at 90.1% purity and 91.23% recovery rate