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The iron blast furnace is the most widely used and efficient producer of liquid iron; however, emissions from sintering and coking cause environmental pressure for the integrated steel works. The combustion of coke fines (breeze) during sintering contributes to greenhouse gases (e.g. carbon dioxide) and is a source of SO x and NO x emissions. Coking capacity is also constrained by environmental concerns and economic factors, such as increased coke consumption and short supply is leading to high prices. Improved coking practices, which result in reduced production of fines, are also contributing to the tight availability of breeze for sintering. This combination of factors presents an opportunity to consider alternatives to coke as a fuel for sintering. CSIRO Minerals has been investigating the use of wood biomass/char as a substitute for coke during sintering. Wood biomass, or char produced from it, is an attractive carbon source as carbon dioxide liberated during combustion can be sequestered back into growing biomass. It has great potential to reduce the emissions from integrated steelworks and improve their environmental acceptability. Harvested biomass/char is also a renewable and sustainable resource and can be integrated with good land management practices such as remediation of salinity affected land. Weeds, especially woody weeds, can also be used as a source of biomass for charcoal and integrating char production with weed management can help address a pressing environmental issue in Australia. Previous reported preliminary testwork indicated that the use of Red Gum char as a replacement for coke resulted in a product sinter of comparable quality, improvements in productivity and significant reductions in SO x and NO x emissions. In the latest testwork, CSIRO has examined the properties of a range of potential charcoals and has conducted a further series of granulation and small scale sintering trials with them in simulated Japanese Steel Mill iron ore blends. Sinter fuels characterised and evaluated include industry sourced coke breeze, commercially available wood char and a charcoal from prickly acacia (acacia nilotica). Prickly acacia has been declared a noxious weed, is widespread in Australia and is classified as a 'weed of national significance'. The results presented in this paper support the notion that charcoal outperforms coke in many aspects of iron ore sintering and factoring in environmental considerations makes the switch to charcoal even more favourable.

Direct coal liquefaction (DCL) is a process for converting coal to synthetic oils, which can be refined to make transportation fuels. Residue from this process contains inorganic material such as mineral matter originating from the coal and catalysts, and organic matter such as unconverted coal, heavy oils, pre-asphaltenes and asphaltenes. The conversion of these DCL residues to lighter, high-value products is an important step in helping to make this technology both commercially viable and environmentally acceptable. This paper provides an overview of the physico-chemical characteristics and processing options available for coal liquefaction residues and compares and contrasts them to those of petroleum residues. Residue properties vary considerably, since they are highly dependent on feed coal, process configuration and operating conditions. Determination of composition and structural parameters of products derived from residue conversion can help determine their stability, coking and solvent hydrogen donating ability. Thermal conversion processes such as visbreaking and gasification offer the greatest promise for handling these heavy materials. The conversion chemistry, reactivity and kinetics of residue gasification are not well-understood but are important in optimising hydrogen production for the process. The literature has been comprehensively reviewed to provide characteristics and properties of residues and their potential for conversion. In addition, the potential for producing high-value carbon products from residues is briefly discussed.

Manganese furnace dust is made up of volatiles and raw materials fines collected from the off-gas during smelting of manganese alloys. Currently, manganese furnace dust is accumulated in large settling ponds. Major factors preventing recycling of the manganese furnace dust to the ferroalloy furnaces are handling, due to its tar content, and accumulation of zinc in the furnaces, which can cause irregularities in their operation. This paper presents characteristics of manganese furnace dust generated in ferromanganese and silicomanganese production at Tasmanian Electrometallurgical Company and analyses zinc balances in light of furnace dust recycling. If manganese furnace dust is recycled to the ferroalloy furnaces via the sinter plant, the overall zinc input will increase by 51-143 % depending on charging materials.