Low CO2 emission technologies for iron and steelmaking as well as titania slag production

Orth, Andreas; Anastasijević, N.; Eichberger, Heinz

doi:10.1016/j.mineng.2007.02.007

Cited by 84 publications

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“…The GWP values of 2.17 kg CO 2 e/kg steel (sintering) and 2.40 kg CO 2 e/kg steel (pelletising) given in Table 5 for the traditional integrated route using coke are not too different to the values reported by other workers for this route using similar LCA methodology, e.g. Orth et al 21) (2.20 kg CO 2 e/kg steel), Scaife et al 22) (2.16 kg CO 2 e/kg steel) and Pirat 23) (2.0 kg CO 2 e/kg steel). Similarly, the GWP value of 0.51 kg CO 2 e/kg steel given in Table 5 for the mini-mill/EAF route (100 % scrap) is not too different to the value of 0.54 kg CO 2 e/kg steel reported by Sandberg et al 24) for this route.…”

Section: Life Cycle Assessment Of Steelmaking Processesmentioning

confidence: 51%

Environmental and Economic Aspects of Charcoal Use in Steelmaking

2009

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The use of charcoal as a fuel and reductant in ironmaking and steelmaking in place of fossil fuel-based carbon sources has been assessed from both an environmental and economic point of view. Life cycle assessment methodology has been used to indicate potential reductions in greenhouse gas emissions resulting from charcoal substitution rates up to 100 % in the integrated, direct smelting and mini-mill routes for steelmaking. The results indicated that based on typical costs of charcoal and coal, charcoal is not competitive with coal in the steelmaking applications considered. However, the introduction of a carbon trading scheme or carbon taxes can be expected to improve the competitiveness of charcoal compared to coal. Based on a long-term price of $US90/t for metallurgical coal, a carbon tax in the order of US$30-35/t CO 2 would be required with the direct smelting and integrated routes for the overall charcoal and coal costs to be roughly equal, including a charcoal electricity co-product credit. However, if the recent increase in price of metallurgical coal is sustained for an extended period of time, the required carbon tax rate would fall to about US$18/t CO 2 .KEY WORDS: charcoal; steelmaking; life cycle assessment; greenhouse gases; costs; carbon taxes. © 2009 ISIJ Steelmaking and Opportunities for Charcoal UseThe integrated steelmaking route begins with iron ore extracted from the earth. After crushing and screening, the iron ore fines are either sintered or pelletised and then fed into the blast furnace along with iron ore lump. Coke, produced from coal in the coke ovens, is used as a fuel and reductant in the blast furnace together with fluxes to produce pig iron. Natural gas is also commonly used as a supplementary fuel in the blast furnace. The pig iron is transferred to the basic oxygen furnace (BOF) along with steel scrap, where oxygen is used to refine the pig iron into steel by reducing the carbon content.In direct smelting processes, smelting takes place in a single reactor where ore and coal are both charged into the same melt or bath (hence the name "bath smelting"). The processes utilise post combustion of the process offgases, the heat released being transferred back to the bath to compensate for the endothermic smelting reactions. The HIsmelt process produces molten iron utilising fine iron ores (and other iron-bearing fines) and non-coking coals. The iron oxides are rapidly reduced by the bath whilst carbon from the coal dissolves in the bath. The primary product from the HIsmelt process is hot metal (iron). This iron is tapped continuously through an open forehearth and is slagfree. It can be used as direct feed to steelmaking processes or cast into pig iron.The main opportunities for the use of biomass in the integrated route for steelmaking would appear to be:• replacement of coke as a reductant and fuel in the blast furnace; • replacement of coal and natural gas as a fuel in the blast furnace; • replacement of coke as a fuel in sintering and pelletising. However, it has been suggested ...

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Section: Life Cycle Assessment Of Steelmaking Processesmentioning

confidence: 51%

Environmental and Economic Aspects of Charcoal Use in Steelmaking

2009

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“…For achieving a more efficient operation from an energy and economic point of view, various revolutionary technologies are now developed as alternative ironmaking processes such as COREX and FINEX already in commercial operation, Circosmelt and HIsarna 1,2) under development. HIsarna, as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Thermal Decomposition Behaviour of Fine Iron Ore Particles

et al. 2014

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In the smelting cyclone of HIsarna process, both thermal decomposition and gaseous reduction of iron ore contribute to the expected pre-reduction degree about 20%. However, the fine ore reduction and melting process in the smelting cyclone is extremely fast and it is very difficult to differentiate between the thermal decomposition and gaseous reduction. This study focused on the thermal decomposition mechanism of the fine iron ore under different conditions. Firstly, the theoretical evaluation has been conducted based on the thermodynamics, and then the laboratory investigation was conducted in three stages with three reactors: the TGA-DSC, the electrically heated horizontal tube furnace and the High-temperature Drop Tube Furnace (HDTF). According to the experimental results of the first two stages and the theoretical evaluation, it was found that the temperature of intensive thermal decomposition of Fe2O3 in the inert gas environment is in the range of 1 473-1 573 K, while the thermal decomposition of Fe3O4 could be sped up when the temperature is above 1 773 K in the inert gas. Temperature plays an important role in the thermal decomposition degree and reaction rate. Finally, it was found that the thermal decomposition of the individual iron ore particles took place very rapidly in the HDTF and no significant influence of the particle size and residence time (t ≤ 2 020 ms) on the equivalent reduction degree could be observed, when the particle diameter was smaller than 250 μm in the CO2 gas.

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“…[13][14][15] Possible reasons for the scatter of the data is speculated to be caused by the difference in hot metal chemistry and also the in-coming hot metal temperature. The chemical composition of the steel likely changes the thermal conductivity and heat capacity of the melts, which have been documented elsewhere.…”

Section: )mentioning

confidence: 99%

Effect of Hot Metal on Decarburization in the EAF and Dissolved Sulfur, Phosphorous, and Nitrogen Content in the Steel

Lee

Sohn

2015

ISIJ International

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The effect of hot metal additions on the decarburization and dissolved sulfur, phosphorous, and nitrogen content in the steel of a DC EAF was investigated. The addition of hot metal of maximum 36% provided heat into the EAF allowing faster melting and reduced power on times of the furnace. The increased melting rate lowered the FeO in the slag and seems to allow faster kinetics for CaO dissolution into the slag. Hot metal utilization into the slag resulted in higher phosphorous distribution ratios compared to hot metal free heats achieving comparable phosphorous levels at the ladle metallurgical furnace even though the initial input phosphorous was much higher than hot metal free heats. The effect of hot metal on the desulfurization was not pronounced and no apparent difference could be ascertained compared with the 100% scrap charge. With the addition of carbon saturated iron units in the EAF, the evolution of CO and foaming was promoted, which inhibited the infiltration of nitrogen and lowered the overall partial pressure of nitrogen resulting in lower nitrogen levels in the steel. In addition, the dilution effect of the tramp elements Cu and Sn with hot metal ensured the critical defect index to be less than 10% resulting in a 50% reduction of the quality defect index.

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Low CO2 emission technologies for iron and steelmaking as well as titania slag production

Cited by 84 publications

References 0 publications

Environmental and Economic Aspects of Charcoal Use in Steelmaking

Environmental and Economic Aspects of Charcoal Use in Steelmaking

Thermal Decomposition Behaviour of Fine Iron Ore Particles

Effect of Hot Metal on Decarburization in the EAF and Dissolved Sulfur, Phosphorous, and Nitrogen Content in the Steel

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