The students Paulina Koskenniemi and Astrid Mata have studied how the addition of an increased amount of biomass can affect the blast furnace process. If coke can be replaced with biomass, the production can be more environmentally friendly. The results of students' experiments showed that biomass can be used to replace coke to some extent in the blast furnace.
– The biomass must be pre-treated and it makes it a bit too expensive for use in the production today. But sooner or later, coke must be replaced with a sustainable material, says Andreas Lennartsson, Research Assistant in Process Metallurgy at Luleå University of Technology.
200 thousand tonnes of sludge
– A waste product from steel production is the sludge produced in the gas cleaning from the blast furnace. This sludge contains high levels of iron and zinc. The high content of zinc prevents the sludge from being recycled to the blast furnace, said Andreas Lennartsson.
The students Daniel Söderström and Gabriel Luzendu have tried to separate the zinc from sludge. The result shows that there is a potential for separating zinc from the sludge, thereby enable recycling of the iron-rich part back to the process.
– 200 thousand tonnes of sludge is now at landfill, which is a big challenge, and a potentially profitable business for those who find a commercial use for the sludge, concludes Andreas Lennartsson.