For hundreds of years now, metals in smelters have been liquefied using coke, coal or natural gases. The efficiency of the plants has been improved over the years; however, the basic operating principle has always remained the same. With an increasing number of electric arc and induction furnaces, which rely on electrical energy and mainly recycle metals, the efficiency of the furnaces is significantly higher than with fossil fuels. The electrification of steel production is made especially possible due to the fact that increasingly fewer new metals have to be produced. The recycling rate in Europe is higher than ever before: Approximately 70 per cent of the aluminium produced has merely been remelted. This trend will continue in the coming years as recycling becomes more cost-effective than the extraction of new ores.
The longevity of products is also becoming more important again. With the right alloys and coatings, metals can be used for a much longer time than without special treatment. While car bodies are often adequately protected against corrosion, the industry is somewhat more regressive. Economic output is reduced by about four per cent every year due to rust. The numerous closed down mines and furnaces in the Ruhr area, which have been rusting for years, are a good example of what industry would look like without corrosion protection.
Lightweight construction: Same performance with less weight
Increasing raw material costs and advances in the area of environmental protection will also ensure that products made of metal will become ever lighter in the future, particularly in mass production. Fewer metals will need to be melted, and at the same time cars, for example, will benefit from the reduced weight that needs to be moved. The changeover to lightweight construction is not equivalent to a reduction in load capacity. Computer-aided calculations can be used to design components with the same requirements, but which nevertheless weigh considerably less and are made of aluminium instead of steel, for example.
The main topic of the coming decade will certainly be the careful use of natural resources. The demand for fossil fuels and the production of the greenhouse gas CO2 are major factors throughout Europe and are the focus of intense social and political discussions. Environmental protection will continue to accompany the industry and become an even more important criterion.
In addition to social responsibility, regulations such as the CO2 tax will make it necessary to implement environmentally friendly production processes as quickly as possible. The European emissions trading system will ease the situation somewhat for the time being. As licenses become scarcer over time, however, the pan-European economy will face challenges.
Thyssenkrupp presents, for example, how the industry can adapt. In Duisburg, the company is equipping a blast furnace with technology that uses hydrogen as the primary source of energy. The first attempts have been ongoing since 2019; instead of 300 kilogrammes of coke and 200 kilogrammes of coal dust, pure hydrogen is now being used. After combustion, this decomposes into normal water, producing no CO2.
Hydrogen can be extracted directly from water, but this also requires large amounts of energy. For this reason, it makes sense to produce gas by means of green electricity. At the same time, the hydrogen infrastructure must be expanded: Electric mobility could also opt for fuel cells and do without lithium batteries. A well-developed network would lower production prices and would make the conversion to hydrogen in the industry more economical.
With SALCOS, Salzgitter AG also aims to significantly reduce emissions. The principle is similar: Here, too, the focus is on hydrogen as an energy carrier. In the process of direct reduction in the blast furnace with added natural gas, the CO2 produced is filtered out.
