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• Biomass utilisation in iron and steelmaking processes does offer a solution to decrease the environmental impact of steelmaking. • Potentials for biomass application in different parts of (BF-BOF) integrated steelmaking process reviewed. • Biomass upgrading technologies to produce suitable biochar for iron and steelmaking are evaluated. • Insights and recommendations for effective use of biochar as a reducing agent are suggested. This study provides a fundamental literature review of biomass characterisation and application for utilisation as a reducing agent and fuel in an integrated steelmaking process. This review contains and evaluates the existing literature concerning the properties of different biomass sources and available pre-treatment technologies for upgrading biomasses to have similar characteristics to fossil coal. The suitability of biofuels in different operating units including Brazilian mini blast furnaces, cokemaking, larger blast furnace injection, sintering and production of carbon composite agglomerates are analysed. There is a considerable opportunity to reduce CO 2 emissions in the integrated steelmaking process by using biomass-based reducing agents. The literature reports that charcoal optimisation in the integrated steel plant can achieve reduction in net CO 2 emissions of 31–57%, depending on the substitution rate. Although, some level of pre-treatment is also necessary for efficient use of biomass, the pre-treatment requirement will depend on the unit operation where the biomass material is added. Solid biofuels are considered the most suitable form of biomass-based reducing agents due to similarities in the physical properties with the injected coals; this will make coal replacement more straightforward and lower the costs required for plant modifications. [ABSTRACT FROM AUTHOR]

• Devolatilisation behaviours of different carbon sources investigated for HIsarna alternative ironmaking process. • Maximum peaks of evolved gases from VTF-QMS corresponded well to DTG curves. • The kinetic parameters for coal and biomass samples were determined. • Biomass pre-treatment temperature suggested to produce chars with similar properties to coal injected in HIsarna. HIsarna process offers a novel low CO 2 emission alternative to the blast furnace for primary iron production. This new smelting ironmaking technology is flexible in raw material usage such as the substitution of biomass for coal as a reductant. Reduction is conducted through multiple mechanisms within the smelting vessel including gaseous reaction products from thermal decomposition of volatile matters reacting directly with iron oxide containing slags and injected iron ore. In this study, four coals with notable differences in volatile matter content along with two biomass samples sourced from wood and grass origins were investigated for the selection of suitable fuel mix. Thermogravimetric analysis (TGA) was used to measure the weight loss of the carbonaceous materials and a vertical tube furnace coupled with a quadrupole mass spectrometer (VTF-QMS) was employed for off-gas analysis during the devolatilisation. During TGA tests the samples were heated under a 99.9999% argon atmosphere to 1500 °C at three different heating rates to investigate the kinetics of thermal decomposition for these materials. Through use of the Kissinger– Akahira–Sonuse model an average activation energy was determined as a function of the conversion degree. The furnace experiments were carried out under a 99.999% Ar atmosphere to a peak temperature of 1500 °C, at a heating rate of 10 °C/min. The wt% of reducing gases e.g. H 2 , CO, and hydrocarbons, and the temperature required for these gases to evolve was notably different for each materials, but the respective maximum peaks of evolution of these gases corresponded well to the maximum rate of mass loss. Furthermore, the off-gas analysis reveals torrefied grass contains large amount of water and carbon dioxide which will be released at very low temperature, therefore pre-treatment to the temperature of ~400 °C is necessary to produce chars with similar properties to coal injected in HIsarna. [ABSTRACT FROM AUTHOR]