“The project has had a flying start. The exploitation potential of various material flows is studied extensively using a wide range of technologies, through both hydro- and pyrometallurgical processes. At the moment, the focus is on the utilization of slags from steel production and the recycling of sludges from flue gas scrubbing,” says the accountable manager of the project consortium, professor Timo Fabritius from the Process Metallurgy Group.
The project called researchers in the field to a seminar in Oulu on 26 March to discuss methods that could be used to increase the material and energy efficiency, recycling and reuse of materials in metallurgical processes during metal production. The project focuses on residues caused by metallurgical processes: mainly slags, sludges, scales, waste heat and process waters.
“Nowadays, a significant proportion of fine coke, dust and slag fractions are bound with cement, for instance, and fed back into the production processes of iron or steel. The project explores the possibility to replace a proportion of cement with alternative binders made from by-product flows, among other topics,” Fabritius adds.
The project also explores the impact of microwave treatment on the agglomeration of sludges that are wet and difficult to process, on pre-reduction and on the removal of harmful substances that are volatile at a low temperature. According to Fabritius, a common problem with reusing and recycling metals is that elements vaporizing at a relatively low temperature are accumulating in dusts.
“Zinc is a good example of this in steelmaking. In addition, recycling is often restrained by the fact that the material cannot be fed back into the loop as fine dust or sludge, but it has to be agglomerated in some way. We are exploring microwave treatment as one potential alternative solution for these problems,” Fabritius says.
The researchers are interested in which materials absorb microwaves, if oxide materials are reduced or if substances volatile at a low temperature vaporize during the processes, to name a few topics. Moreover, we still do not know if materials agglomerate, how much the temperature increases during the process and what kind of processing times are possibly needed. In addition, the researchers also need to identify how much energy these methods consume.
They are also doing research on the manufacture of calcium-based products with high added value using different methods, from steel production slags, the potential of non-fossil reducing agents, and the use of slags in the manufacture of non-iron metals.
Metal production requires a lot of energy and materials. This is why it is a significant source of carbon dioxide emissions, even though the Finnish metallurgic industry is one of the world leaders in energy and material efficiency. The metallurgic industry also causes large by-product flows, a significant proportion of which is recycled back into the process. Closing material cycles and using even more energy efficient production processes are necessary for enhancing the competitiveness of the metallurgic industry and meeting our emission targets.
In the best case scenario, the research gives birth to new innovations and new business. The University of Oulu supports the project with its expertise in the processing of dusts, sludges and process waters, and the development of new measurement technologies used in process control. The project has also created new opportunities for cooperation between universities and companies.
“There are attempts to generate new business related to the production of calcium-based products and chemicals, among other things. On the university’s behalf, the consortium is open for everyone, but we would probably achieve the best added value if new SMEs would join the consortium to develop and pilot their own analysis and processing methods to exploit various by-product flows,” Fabritius adds.
All universities in the project are cooperating internationally on a large scale. The cooperation includes researcher exchange, for instance with Germany and China, international co-publications and the preparation of common European project portfolios in the field of circular economies, among other things.
The total budget of this two-year project is approximately EUR 6.9 million, and the participants of the project include ten companies and four universities and research organizations. The project is funded by Business Finland and the partners of the consortium.
The participants of the project include Aalto University, Boliden Harjavalta Ltd, Boliden Kokkola Ltd, Lappeenranta-Lahti University of Technology, Luxmet Ltd, University of Oulu, Outokumpu Stainless Ltd, Outotec (Finland) Ltd, Owatec Ltd, SSAB Europe Ltd, Tapojärvi Ltd and VTT Technical Research Centre of Finland Ltd. In addition, Timegate Instruments Oy is included as a cooperation partner.
Text: Sirpa Mustonen