This paper studies the possibility of developing a new heat recovery system from various hot wastes generated by the steelmaking industry, by utilizing the endothermic heat of reaction instead of sensible heat. In the proposed system, the waste heat of the gas was first stored using a Phase Change Material (PCM), and then supplied to an endothermic, methane-steam reforming reaction (MSR) as a heat source. The molten slag was granulated using a rotary cup atomizer (RCA) and the sensible heat of the slag was recovered using MSR. A heat and material balance model was developed to evaluate this system and to predict all its operating data. An exergy analysis and an economic evaluation were conducted on the basis of the predicted data. The results showed that the exergy loss in the proposed system was only 15 % from the total exergy losses in the conventional system, and that the annual cost benefit of the proposed system totaled US$ 409 million from heat recovery, and US$ 1 945 million from slag granulation.

This paper describes fundamental experiments of a new biomass ironmaking that employs low-grade iron ore and woody biomass for promoting the direct reduction, FeO + C ) Fe + CO, in which dehydrated, porous limonite iron ore was filled with carbon deposited from the biomass tar, biotar. In our experiments, three types of iron ores containing different amounts of combined water (CW; 1.6, 3.8, and 9.0 mass %) were first dehydrated at 450°C to make them porous and then heated with pine tree biomass at 500-600°C for the gasification and the tar vapor generated was decomposed to deposit carbon within/on the porous ores. The dehydration treatment made the iron ores porous by removing CW and significantly increased their Brunauer-Emmett-Teller (BET) specific surface areas and porosities. In the second treatment of biomass gasification and decomposition of tar vapor, the biomass was changed into char, tar vapor, and reducing gas; the biotar was decomposed and carbonized within the porous ores. Interestingly, the ores caught biotar effectively, not only on the surface but also inside their pores. Here, the ores with the nanosized pores served as catalysts for tar carbonization with gas generation. Simultaneously, the ores were partially reduced to magnetite by the reducing gas. The ores containing carbonized material were easily reduced to iron by only heating until 900°C in a nitrogen atmosphere; this was due to the direct contact of carbon and iron oxide within the ores, so-called direct reduction. In conclusion, the dehydrated limonite iron ore was most effective for avoiding the generation of sticky tar in the biomass gasification and for filling the porous ore with carbon from tar. The product is a promising raw material for biomass ironmaking. The results appealed an innovative ironmaking method with a large reduction of carbon dioxide emission using low-grade iron ore and woody biomass.

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Effective use of local iron ore and biomass waste as energy and material resources in iron making is an interesting economic prospect since Malaysia imports iron ore to supply its domestic steel consumption while there is an abundance of biomass waste from the palm oil industry. In this work, a composite pellet made of Malaysian iron ore with palm kernel shell (PKS) waste was subjected to reduction tests using an electric tube furnace to investigate the effect of temperature and PKS content on reduction rate. Several iron ore samples taken from different mining locations were subjected to thermal and X-ray diffraction (XRD) analysis. The rate of iron ore reduction increased with increasing temperature up to 900°C. XRD analysis revealed that the original iron ore mainly contains iron oxide hydrate and was converted into simple hematite after heating and then become magnetite after reduction. The Fe content in the original ore increased almost 12% when 40wt% of PKS was used. The iron oxide was successfully

In this paper, we describe an innovative process involving iron reduction through chemical vapor deposition for applications in the ironmaking industry. In our experiment, we produced tar vapors from pyrolysis of various solid fuels, including high-grade bituminous coal (HGC), low-grade lignite coal (LGC), and biomass palm kernel shell (PKS), and decomposed these vapors into gases, carbon, and light hydrocarbon. Carbon was deposited within the pores of pisolite ore (low-grade ore), which became porous during the dehydration process at 450 °C. We determined that the amount of tar produced during pyrolysis strongly affected carbon deposition, and HGC produced the highest carbon deposition because of its large tar product. In addition to tar amount, surface area and pore volume also played important roles in this process. PKS had the highest ratio of deposited carbon because it produced the smallest quantities of reacted tar and, consequently, the largest numbers of vacant pores. The amount of carbon deposition decreased at higher temperatures because tar was easily converted to a gaseous phase. The deposited carbon within iron ore showed potential as a reducing agent because it was highly reactive and reduced at lower temperatures. Carbon deposited within iron pores dramatically reduced the contact distance between the iron ore and carbon. Thus, these results show that our proposed methodology could have important applications as an alternative low-energy approach for producing metallic iron using low-grade materials.