John G Mathieson

Strength and bonding in reduced ironsand–coal compacts

Abstract In this investigation, the strength and bonding within reduced ironsand–coal compacts were studied, with the aim of better understanding the binding mechanisms in the reduced compacts and, based on this understanding, to improve their strength. Ironsand ore and sub-bituminous coal were mixed and pressed into compacts, which were reduced by heating in a thermogravimetric furnace to temperatures between 1273 and 1573 K under argon. The progress of the reaction was monitored by measuring the weight loss with time. The reduced compacts were found to have low strength in compression testing. The main form of bonding between the reduced ironsand particles in the compact was by the formation of a slag-like material. Increasing the final reduction temperature was found to have a profound effect on the strength of the compacts by promoting the formation of this slag-like material.

Low Emission Steelmaking

Steel is one of the most important structural materials in the world. It is used in virtually all industry sectors and, after cement, is the leading manmade material produced, with the annual production rate reaching 1660 million tonnes in 2014 [1]. Through continuous development and implementation of incremental technologies, the steel industry has improved its energy efficiency and reduced its specific energy consumption by about 60 % over the past 50–60 years. The close linkage between energy consumption and CO2 emission has resulted in a similar reduction in specific CO2 emission, where currently about 2.2 t CO2 is produced per tonne of crude steel manufactured through efficient integrated blast furnace and BOF plants [2]. Climate Change was understood fairly early in Europe not only as a challenge for society, but also as an opportunity for the carbon-intensive steel sector to explore radically new steel production technologies, even before the Kyoto protocol was signed [3]. Many wide-ranging studies were conducted to identify solution paths at a company level and in an international context [4–6]. The work carried out then showed that to reduce the specific emissions of the steel sector to the level of climate change expectation, i.e., 50 % or preferably more, it was necessary to introduce deep paradigm changes in the way steel is made, as the existing production routes had only a small leeway for improvement, 15 % or less for the world class steel mills. Similarly, in Japan work commenced in 1999 on a fiveyear feasibility study on ‘‘Innovative Ironmaking Reactions in New BF to Aim at Halving Energy Needs and Minimising Environmental Load.’’ This project involved the four major steelmakers and 12 universities and other institutions. It was coordinated by Professor Kuniyoshi Ishii for the ISIJ and has often been termed the ‘‘Ishii Project’’ [7]. In the early 2000s, conditions seemed prospective in Europe in terms of a favorable political context to move from paper studies to the experimental exploration of solutions. Indeed, the EU had started taking the lead in announcing the type of low-carbon economy that would be necessary. A large consortium of 40 partners was brought together, comprising most of the steel sector in the EU and many Universities and Research Centres from 11 countries. A research proposal, answering a coordinated European Research call from the United Nations’ 6th Framework Program on climate change and the Research Fund for Coal and Steel (RFCS), was presented and won the competition in 2004. Thus, the 5-year Ultra Low CO2 Steel (ULCOS) production program was born, coordinated by Dr. JeanPierre Birat of ArcelorMittal. At that time, Dr. Birat was also active at the International Iron and Steel Institute renamed in 2008 to the World Steel Association (worldsteel) and initiated its CO2 Breakthrough Coordination Program, which allowed contributions from all regions/countries to the development of technologies that could result in at least 50 % reduction in The contributing editor for this article was S. Kitamura.

Current Status and Future Direction of Low-Emission Integrated Steelmaking Process

In 2006 the Australian steel industry and CSIRO initiated an R&D program to reduce the industry’s net greenhouse emission by at least 50%. Given that most of the CO2 emissions in steel production occur during the reduction of iron ore to hot metal through use of coal and coke, a key focus of this program has been to substitute these with renewable carbon (charcoal) sourced from sustainable sources such as plantations of biomass species. Another key component of the program has been to recover the waste heat from molten slags and produce a by-product that could be substituted for Portland cement.

Utilization of biomass as an alternative fuel in ironmaking

Abstract Raw biomass is unsuitable for ironmaking applications. However, after pyrolysis, the resultant chars can substitute for conventional nonrenewable fuels and reductants. Provided that the renewable fuels are produced sustainably, they have great potential to lower net CO2 emissions from an integrated steel plant without the need for significant capital expenditure. Charcoal properties can be tailored for optimal performance, and applications in cokemaking, sintering, and the blast furnace are presented. Potential applicability to alternate and emerging ironmaking processes is discussed. This chapter discusses recent R&D for the 10 applications identified and also presents progress toward a versatile large-scale pyrolysis process.