Remoção de óxidos de ferro de uma fonte ornamental quinhentista pertencente à Quinta da Cardiga (Torres Novas, Portugal)

Nuno Pereira; Marco Rocha; Manuel Rosa; Fernando Costa

doi:10.14568/cp2018063

Authors

Nuno Pereira Instituto Politécnico de Tomar, Estrada da Serra, 2300-313 Tomar, Portugal
Marco Rocha Instituto Politécnico de Tomar, Estrada da Serra, 2300-313 Tomar, Portugal
Manuel Rosa Instituto Politécnico de Tomar, Estrada da Serra, 2300-313 Tomar, Portugal; Techn&Art – Centro de Tecnologia, Restauro e Valorização das Artes, Instituto Politécnico de Tomar, Estrada da Serra, 2300-313 Tomar, Portugal https://orcid.org/0000-0003-0768-6714
Fernando Costa Instituto Politécnico de Tomar, Estrada da Serra, 2300-313 Tomar, Portugal; Techn&Art – Centro de Tecnologia, Restauro e Valorização das Artes, Instituto Politécnico de Tomar, Estrada da Serra, 2300-313 Tomar, Portugal https://orcid.org/0000-0002-2726-1679

DOI:

https://doi.org/10.14568/cp2018063

Keywords:

Conservation, Restoration, Marble, Chelants, Spectrophotometry

Abstract

The ornamental fountain in marble and breccia is a 16th century Italian work integrated in the small courtyard of the Cardiga Palace (Torres Novas, Portugal) currently in restauration process. The iron spikes used to connect the constituent elements were corroded and contaminating the base stone elements surfaces with intense stains of metallic oxides. There was a suspicion that, apart the surface, these oxides could have migrated in depth through the porous structure of the material. The performance of the iron oxides removal tests was evaluated using optical measurements in the CIELAB color space after each chelant application. Sodium dithionite was found to exert a substantially higher cleaning action than ammonium citrate. After finishing the treatment with the most efficient chelant, the chelating action was verified below the surface of the marble. It was found that at the depth of 1 mm the material remained contaminated with iron oxides, with an evident color contrast with a treated surface.

Received: 2018-12-8
Revised: 2019-3-11
Accepted: 2019-4-5
Online: 2019-4-24
Published: 2020-7-31

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References

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