An investigation of the chemical composition and acid corrosion of pedra sabão (soapstone)

Abstract

In this paper the results of a basic study of the chemical composition and structure of soapstone are reported. An investigation of the effects of aqueous sulfuric acid solutions on the physical integrity of the stone was also performed. The studied soapstone samples had a lamellar nanostructure as verified by DRX data. Furthermore, they contained isolated silanol (Si–OH) groups, as indicated by FTIR data, and the majority of the silicon atoms were bonded to OH groups, as shown by 29Si CPMAS NMR analysis. Is was also shown that a low resistance to acid attack is associated with a large amount of magnesium and/or iron in the stone.

Keywords

• soapstone
• acid rain
• chemical composition
• baroque art.