New EU project produces a suitable oxide slag in cast iron foundries preserving the environment and the reduction of CO2 emissions

The project will start this month and involves the University of Padua, OPIGEO, ITALGHISA, ZAG and ZEROCENTO, who will join forces to demonstrate the sustainability of a new Slag process.

Named the STILL METAL project (SustaInable sLag process to obtain a valuabLe METAL), and supported by EIT RawMaterials, this project aims to solve the problem of the slags generated in cast iron foundries. This is achieved through a process which transforms the slag into two valuable materials. The slag from cast iron foundries is considered waste because, in comparison with other slag types, it cannot be reused and must be disposed of in landfill which comes with an environmental price tag.

The process involves the reaction at high temperatures, in the molten state, between the slags and specific added materials. The result is a material that has a composition of a Ferroalloy, a valuable alloy of iron containing silicon, that can be sold or reused inside the same foundry for the production of new cast iron.

In comparison with the production of primary ferroalloys, the residual oxide slag obtained with this process will result in a 70% reduction of CO2 emissions. In addition, it comprises a mix of oxides of aluminium, silicon and alkali which have a market value for the ceramic and/or cement industry. The oxide slag is a calcium/magnesium aluminosilicate with a variable composition depending on the starting foundry slag. This material can be used as an addition to cements, or it can be used in the manufacture of terracotta and/or traditional ceramics, introducing a great example of industrial symbiosis.