Dissolution of salts crystallised in building materials using ultrasound: an alternative to NORMAL (1983) standard methodology.
Our aim in the present work is to extract salts from ornamental stone using a faster and less tedious method than the customarily used NORMAL method [NORMAL, Dosaggio dei Sali Solubili, CNR-ICR, Roma, Italy (1983) 13/83]. For extraction in aqueous medium, the latter method requires shaking for 72 h at a temperature of 60 degrees C. Our aim is to attempt to shorten this time to less than 1 h using ultrasound. The results of the present study indicate that there is a good correlation between the amount of salts extracted applying the method described in the NORMAL (1983) normative and the amounts extracted with the method proposed here, subjecting the material to ultrasound (50 KHz) for 45 min.
Removal of salts from granite by sepiolite
Abstract A study has been carried out on the extraction of salts from different types of granite using patent sepiolite formulation. The ability to remove salts greatly depends on the mineralogical compositions of the granites. Two types of equilibria are important: the absorption and/or adsorption of salts on the stone, and the partition of ions constituting the salt in the adsorbed state between the clay minerals in the rocks and that used as an extracting agent.
Clay mineralogy as the key factor in weathering of ‘arenisca dorada’ (golden sandstone) of Salamanca, Spain
Degradation of stones used as building materials is caused by physical or chemical processes, the intensity of which depends on the mineralogical composition and fabric of the stone and the environmental conditions to which it is exposed. 'Arenisca dorada', an attractive golden-coloured stone, easily dressed under wet conditions, has been used extensively in the construction and ornamentation of a large number of buildings of historical and artistic importance in the city of Salamanca. The development of 'Plateresco' architecture owes much to the special properties of this stone. Weathering of arenisca dorada in Salamanca has been a cause of great concern among scientists, architects and artists, and a thorough study of its causes is an urgent necessity. Studies are being carried out at the research unit of physical chemistry and mineralogy of clays at the Centro de Edafologia y Biologia Aplicada, Salamanca, these involving collaborative efforts by chemists (Dr M. S~inchez-Camazano and the present author), architects (Dr F. Lombardia-Morcillo and Dr I. Vicente-Garcia), and geologists (Dr J. Saavedra-Alonso). In this note the preliminary results of the studies are presented.