Recycling of Waste V2O5–WO3/TiO2 Catalysts in the Iron Ore Sintering Process Via a Preballing Approach

Extensive use of selective catalytic reduction denitrogenation technology leads to the generation of a large amount of hazardous waste vanadium–tungsten–titanium catalysts. To valorize these waste catalysts, a new technology for the recycling of waste catalysts in steelworks was proposed, in which waste catalysts were added to the iron ore sintering process for preparing titanium-bearing sinter for blast furnace hearth protection. The effects of adding the waste catalyst on sinter product quality indexes were investigated by sinter pot tests. The results confirmed that adding 0.5–2.0 wt % waste catalysts had no obvious negative impact on sinter product quality indexes, but caused a substantial decrease in reducibility of the finished sinter product due to the introduction of titanium oxide. Based on this result, a novel preballing approach was developed, in which the waste catalyst was preballed with magnetite, and the granulated pellets were then sintered with the sintering mixture. It was found that by preballing the waste catalyst at 1 wt % with magnetite improved the permeability and enhanced the sintering indexes, without changing the reducibility properties of the finished sinter product. Moreover, titanium oxide reacted within the pellet to form ilmenite that was wrapped within the pellet. This work thus provided a promising approach for waste catalyst utilization.