Digitalization represents a paramount process started some decades ago, but which received a strong acceleration by Industry 4.0 and now directly impacts all the process and manufacturing sectors. It is expected to allow the European industry to increase its production efficiency and its sustainability. In particular, in the energy-intensive industries, such as the steel industry, digitalization concerns the application of the related technologies to the production processes, focusing on two main often overlapping directions: Advanced tools for the optimization of the production chain and specific technologies for low-carbon and sustainable production. Furthermore, the rapid evolution of the technologies in the steel sector require the continuous update of the skills of the industrial workforce. The present review paper, resulting from a recent study developed inside a Blueprint European project, introduces the context of digitalization and some important definitions in both the European industry and the European iron and steel sector. The current technological transformation is depicted, and the main developments funded by European Research Programs are analyzed. Moreover, the impact of digitalization on the steel industry workforce are considered together with the foreseen economic developments.

Over the last few decades, the European steel industry has focused its efforts on the improvement of by-product recovery and quality, based not only on existing technologies, but also on the development of innovative sustainable solutions. These activities have led the steel industry to save natural resources and to reduce its environmental impact, resulting in being closer to its “zero-waste” goal. In addition, the concept of Circular Economy has been recently strongly emphasised at a European level. The opportunity is perceived of improving the environmental sustainability of the steel production by saving primary raw materials and costs related to by-products and waste landfilling. The aim of this review paper was to analyse the most recent results on the reuse and recycling of by-products of the steelmaking cycles as well as on the exploitation of by-products from other activities outside the steel production cycle, such as alternative carbon sources (e.g., biomasses and plastics). The most relevant results are identified and a global vision of the state-of-the-art is extracted, in order to provide a comprehensive overview of the main outcomes achieved by the European steel industry and of the ongoing or potential synergies with other industrial sectors.

The steel industry is among the highest carbon-emitting industrial sectors. Since the steel production process is already exhaustively optimized, alternative routes are sought in order to increase carbon efficiency and reduce these emissions. During steel production, three main carbon-containing off-gases are generated: blast furnace gas, coke oven gas and basic oxygen furnace gas. In the present work, the addition of renewable hydrogen by electrolysis to those steelworks off-gases is studied for the production of methane and methanol. Different case scenarios are investigated using AspenPlusTM flowsheet simulations, which differ on the end-product, the feedstock flowrates and on the production of power. Each case study is evaluated in terms of hydrogen and electrolysis requirements, carbon conversion, hydrogen consumption, and product yields. The findings of this study showed that the electrolysis requirements surpass the energy content of the steelwork’s feedstock. However, for the methanol synthesis cases, substantial improvements can be achieved if recycling a significant amount of the residual hydrogen.

An improvement of by-products reuse contributes to reduce the environmental impact of industries and to increase their competitiveness. Within the steel production cycle, several by-products are produced: slags, sludges, scales, dusts. Some of them are directly suitable to the internal reuse, other ones can be separated in fractions that can\ud be used internally or sold for external use. This paper shows an analysis focused on the optimization of by-products reuse in an Italian Integrated Steelworks with a particular attention on the internal recycling in the pelletization process. Starting from previous studies on the selection of suitable by-products and treatments, the paper presents, firstly, the development of a superstructure model using reMIND® software in order to find optimal solutions, considering quality and environmental constraints, and to minimize operating costs. Furthermore, the evaluation and the optimization through laboratory or simulation tests of possible mixtures of by-products to be used in pelletization is also discussed. By-product mixtures were evaluated to the aim of achieving good pellets formation, according to the number, size of pellets and the compression test results. This study shows that a particular scenario is capable to jointly reduce costs and environmental impact as well as to obtain high quality pellets that can maximize the internal reuse in sinter plant of by-products in a particular "winning formula" (BOF slag 65wt%, BOF sludge 27wt%, dolime 1wt%, cement 7wt%). These preliminary results show that a good by-products management could provide\ud important advantages to the companies by contributing to the "zero waste" target

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