Metallurgy Research Centre

  • 9 de enero de 2023

Development of foundry cores and molds from regenerated sand

The HICORE Project aims at developin a solution of high environmental and economic impact that will offer a new way of recovering green molding sands, with cyrcular economy approach for the foundry sector.

The molding sands represent the 5th stream of non-hazardous waste in the Basque Country. This waste stream has its origin in the molds and cores in which the castings solidify, and which are destroyed after components being demolded. The "green molding" sands, used in the production of molds by mixing silica sand and bentonite, are the most voluminous waste stream of the foundry sector, both in the Basque Country and in Europe.  

With the challenge posed by the recovery and revalorisation of these sands, the HICORE project, participated by three foundries generating more than half of the green molding sands in the Basque Country, BETSAIDE S.A.L. (project leader), FAGOR EDERLAN S.COOP. and METAL SMELTING S.A., is targeted to promote the reuse of spent foundry sands in applications with greater added value within the casting process itself. Specifically, to manufacture of new cores.

As explained by Lucía Unamunzaga, head of the Sustainability and Environment research line of AZTERLAN, "although it is usual to reuse recovered spents sand to manufacture new casting molds, with regard to the manufacture of cores, new sand is used. The reason for that is that the characteristics of the residual sands from green molding are incompatible with the chemical agglomeration system (phenolic urethane system) used in the manufacture of these elements".  Therefore, "in to achieve the objective of revalorization of spent sand in the manufacture of cores, it is essential to develop an advanced regeneration system that will ensure a high-quality sand".

The new cores manufactured with the recovered sand must allow to manufacture components with all the quality and safety guarantees, and to do so at industrial production levels. "The commitment of all the agents involved in this project is to demonstrate the viability of this development by manufacturing prototypes of iron castings using these new cores (and molds)."

High environmental and economic impact

To achieve this goal, HICORE will define a new process of regeneration of green sands capable of transforming them into a material compatible with the phenolic urethane system, in which, as Lucía details, "it will be especially critical to achieve the maximum elimination of bentonite, coal and metal particles, guaranteeing high cleaning rates".

Thanks to this development, the foundries participating in the project, BETSAIDE S.A.L., METAL SMELTING S.A. and FAGOR EDERLAN S.COOP., they expect to be able to recover the 36,000 t/year of total sands that they deposit in landfill. "We calculate that this will result in a cost reduction of more than 4M ¤  / year, both in terms of savings when it comes to deposition in landfill and not having to purchase new sand". From an environmental point of view "we also expect to achieve a significant impact by reducing the extraction of new sand from quarries and by cutting the 3,600 t CO2 / year emissions associated with such extraction and sand processing (0.1t CO2 / t sand)".

The HICORE project consortium "Development and validation of cast components with a low environmental footprint based on an innovative regenerated core manufacturing technology" is made up of the foundries BETSAIDE S.A.L., FAGOR EDERLAN S.COOP. and METAL SMELTING S.A., the AZTERLAN Technology Centre member of BRTA, the ASSOCIATION OF FOUNDRIES OF THE BASQUE COUNTRY AND NAVARRA (AFV) and the TABIRA FOUNDRY INSTITUTE. The project is funded by the Basque Government through the R+D aid program Hazitek 2022.

Hicore

Representatives of the organizations and companies participating in the HICORE project in the project launch meeting