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Sustainable metal (Fe) recovery using stamp press bricks made of dusts and sludges from iron and steel making processes

In 2020 approximately 1.5 million tons of dusts and sludges were produced in German steel plants along the integrated steel route via blast furnace and LD converter. This residues from steel making still contain considerable amounts of Fe-oxides as wustite, magnetite and hematite. Thereby, these residues are undergoing intense internal recycling for Fe recovery. However, the fine particle size and the high moisture often hampers the direct recycling in the blast furnace. Thus, the materials are today sintered together with primary resources in the sinter plant or being agglomerated with cement in brick plants.

With the ongoing decarbonization of the European steel industry blast furnaces as well as sinter plants being replaced by DRI furnaces and smelter aggregates like electric-arc furnaces, which producing comparable amounts of dusts and filter sludges. Therefore, the internal recycling of dust and sludge must find other methods within steel making. In the presented study, agglomerate bricks produced by a stamp press are investigated for their potential of dust and sludge recycling in electric-arc and shaft furnaces. Due to oxidic Fe-minerals present in the residues, the bricks need to have self-reducing properties which can be achieved by the addition of reducing agents needed for mineralogical modification. Satisfactory self-reduction properties were proven by high grades of metallization for the tested sample materials with limited coke content. By the application of wheat and potato starch as alternative binder and reduction agent, CO2 emission can be decreased tremendously as demonstrated by larger scale furnace experiments.


Lars Gronen1, Carsten Gondorf2, Thomas Willms2, David Algermissen1, Lorenz Mild2, Thomas Echterhof2, Herbert Pfeifer2
1FEhS Building Materials Institute e.V., Germany; 2Department for Industrial Furnaces and Heat Engineering, RWTH-Aachen University
GeoMinKöln 2022
applied mineralogy