Zinc Reduction/Vaporisation Behaviour from Metallurgical Wastes

The steelmaking industry produces large quantities of zinc-bearing wastes of varying forms that cannot be treated through integrated steelmaking processes. Simultaneously, by-products of the zinc industry containing great amounts of iron and zinc are stored or landfilled. The amount of zinc in these materials is generally below that which is of value to be recycled directly to the zinc smelter, consequently a method of concentration is required. Tata Steel owns and operates the pilot HIsarna ironmaking plant which, due to its high raw materials flexibility, is attractive for the purpose of processing secondary iron sources. Furthermore, it can facilitate the simultaneous recovery of a zinc-enriched flue dust. The high temperature behaviour of various waste materials will be presented with regards to their recyclability in the HIsarna furnace. Blast furnace (BF) sludge and basic oxygen furnace (BOF) sludge from Tata Steel IJmuiden have been studied along with ‘goethite’ waste produced by Nyrstar. The various input materials have been comprehensively characterised and their reduction/vaporisation behaviour recorded. Mixed samples have been produced and tested in order to define the most appropriate form of delivery of these materials to the HIsarna furnace.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.(OLD) MSE-3(OLD) MSE-

Experimental and Discrete Element Method Analysis of Galvanized Steel Scrap Particles Along and After an Inclined Chute

HIsarna is a novel ironmaking process with great raw materials versatility that is attractive for various secondary resources. Among the materials that can be recycled, there is steel scrap which is fed to the furnace bath through an inclined chute. The velocity distribution of the scrap particles along the chute affects the particles’ distribution on the liquid slag and, thereupon, the efficient operation of the reactor. In this study, the flow of steel scrap particles along an inclined chute with the same dimensions as those of the actual chute of the HIsarna plant is investigated experimentally and numerically. The simulations are validated using chute tip velocity and mass fractions collected at the different compartments of a sampling device. Translational and angular velocity distributions along and across the chute are reported, and the effect of different parameters are investigated. The impact of the shape of the particles on the simulation process is found to be negligible. The angular velocity distribution in cross-sections of the chute exhibited a V-shaped orientation, whereas the translational velocity displayed similar values across the cross-sections. Moreover, translational velocity appeared to increase with increasing inclination angles, whereas angular velocity increased with decreasing batch size.Team Yongxiang YangTeam Erik Offerma

Zinc Reduction/Vaporisation Behaviour from Metallurgical Wastes

The steelmaking industry produces large quantities of zinc-bearing wastes of varying forms that cannot be treated through integrated steelmaking processes. Simultaneously, by-products of the zinc industry containing great amounts of iron and zinc are stored or landfilled. The amount of zinc in these materials is generally below that which is of value to be recycled directly to the zinc smelter, consequently a method of concentration is required. Tata Steel owns and operates the pilot HIsarna ironmaking plant which, due to its high raw materials flexibility, is attractive for the purpose of processing secondary iron sources. Furthermore, it can facilitate the simultaneous recovery of a zinc-enriched flue dust. The high temperature behaviour of various waste materials will be presented with regards to their recyclability in the HIsarna furnace. Blast furnace (BF) sludge and basic oxygen furnace (BOF) sludge from Tata Steel IJmuiden have been studied along with ‘goethite’ waste produced by Nyrstar. The various input materials have been comprehensively characterised and their reduction/vaporisation behaviour recorded. Mixed samples have been produced and tested in order to define the most appropriate form of delivery of these materials to the HIsarna furnace.</p

Zinc Vaporization and Self-reduction Behavior of Industrial Waste Residues for Recycling to the HIsarna Furnace

Within the steelmaking industry, a large amount of zinc-bearing waste is produced which cannot be effectively treated through integrated steel mills. Concurrently, zinc smelters generate waste residues containing significant amounts of iron and zinc which are stored or landfilled. The zinc concentration of iron and steelmaking residues inhibits its recycling to the blast furnace but is insufficient to be sent directly to the zinc producers. Consequently, a means of up-concentration is required. The pilot HIsarna ironmaking furnace has shown potential for processing secondary iron-bearing resources. Furthermore, zinc can be concentrated in the off-gas flue dust, providing an enriched input for zinc smelters. The potential recyclability of blast furnace (BF) and basic oxygen furnace (BOF) dust and ‘goethite’ residue from the zinc industry has been studied. The input materials have been comprehensively characterized and their reduction–vaporization behavior, has been investigated. Individual samples were tested at temperatures of up to 1300 °C. Here, it was shown that minimal reduction of iron and volatilization of zinc occurred in the goethite and BOF samples. Conversely, even at 1000 °C, the BF dust showed complete reduction of iron and removal of zinc within 30 min. This was due to its high carbon content (40 wt%) which can act as a reductant. Consequently, mixtures of BOF dust and goethite with BF dust were studied. It has been shown that mixtures of 30:70 BF dust to goethite and 20:80 BF dust to BOF dust are suitable for recovering zinc to the gas phase and fully reducing the contained iron. Graphical Abstract: [Figure not available: see fulltext.]Team Yongxiang YangInstrumenten groepTeam Erik Offerma

Rhizosphere fungi actively assimilating plant-derived carbon in a grassland soil

Despite the advantages of the next generation sequencing (NGS) techniques, one of their caveats is that they do not differentiate between microbes that are actively participating in carbon cycling in the rhizosphere and microbes performing other functions in the soils. Here we combined DNA-SIP with NGS to investigate which rhizosphere fungi actively assimilate plant-derived carbon. We provided 13CO2 to plants in intact soil cores collected from a grassland and sampled the rhizosphere in a time series to follow the fate of carbon in the rhizosphere mycobiome. We detected a difference between active rhizosphere fungi using plant-derived carbon and the total mycobiota: 58% of fungal species were using fresh rhizodeposits, and an additional 22% of fungal species received carbon several weeks later while 20% were not involved in cycling of freshly photosynthesized carbon. We show that members of Ascomycota, Mucoromycota, and basidiomycete yeasts were first users of freshly photosynthesized carbon, while fungi not using recently fixed carbon consisted mainly of mycelial (non-yeast) Basidiomycota. We conclude that a majority of fungi inhabiting the rhizosphere in this grassland ecosystem are actively using plant derived carbon either directly or via food-web interactions