In steel and metal working operations, only a small share of the iron oxide contained in the large amounts of slag and pickling sludge waste is recovered; the majority goes to landfill sites. One recycling opportunity is to obtain fine spherical iron powders (FSIP) from this type of waste. However, the two main current processes which can do so (the carbonyl process and the atomisation process using argon) have high energy input, low yields, high costs and generate partly toxic substances.
The main objective of the LIFE GreenPowder project is to overcome the disadvantages associated with processes that recycle fine spherical iron particles (FSIP) from wastes generated by the European steel industry. The project will demonstrate the production of FSIP (<15 microns) from iron oxide contained in refined pickling sludge and LD (LinzDonawitz process) slack, both by-products of steel producers. The projects methodology does not produce hazardous substances, cuts energy and carbon footprint by half, and at the same time decreases costs. The FSIP produced can be used, for example, for metal injection moulding (MIM).
Specifically, the projects aims to: build a pilot plant (5 FSIP t/day, continuous process) for the two-step reduction of hydrogen at low temperatures (500-850C), scaled-up from a lab-scale facility (1 t FSIP/day, batch); test and optimise the pilot plant and the produced FSIP for a number of different MIM process types and 3D-printing applications at two subcontractors; contribute to the market uptake of these additive manufacturing technologies (MIM, 3D-printing) with much reduced life cycle impacts compared to, for example, milling; repare the transfer to recycling of other by-products, e.g. dust from steel grit blasting; and propose a new BAT standard (updating the Best Available Techniques Reference Document for Iron and Steel Production) for the implementation of this Green Powder technology.
The project will contribute to the EU Action Plan for the Circular Economy, the Roadmap for a Resource Efficient Europe, the EU Waste Framework Directive, the Action Plan for a competitive and sustainable steel industry and the REACH Regulation (EC) No 1907/2006.
Expected results: fully operational pilot plant (5 t FSIP/day equalling 1.220 t/y, continuous process); validation of the quality of the produced FSIP in three different final applications; demonstration of the economic competitiveness (5 euro/kg with 3.50 euro/kg in the long term); recycling of 1.750 t of iron oxide waste from refined pickling sludge and LD slack; elimination of the use of toxic iron pentacarbonyl Fe(CO)5 in the FSIP production. Green powder does not use or result in any hazardous substances (only water vapour); ORC process (Organic Rankine Cycle) to recover energy from the water vapour; 50% less energy demand (and CO2 output - in total 36.000 t CO2 until project end); validation of the environmental benefits (e.g. simplified Life Cycle Analysis); and eight serious partners for potential replication plants, of which 1 will receive replication planning support during the LIFE project and the other 7 after the end of the LIFE project.