Efficiency and resistance of the artificial oxalate protection treatment on marble against chemical weathering

Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods

“…3-5). This fact is in accordance with previous research [13,21], where it has been proven that the oxalate layer is not homogeneous and of equal thickness on the entire treated surface because of the different dissolution of Ca 2+ and CO 3 2− ions from the calcite surface and different crystal nucleation across the entire surface. Occurrence of Reststrahlen bands is influenced by usage of a smaller analytical window.…”

“…As the immersion method should be most effective in the creation of CaOx, this treatment method shows the most intense R bands. This fact can be seen from previous research where longer treatments, which can be considered as more effective, create the most intense R bands [21].…”

“…This layer will be similar to that obtained by a 10 to 15 h poultice treatment, which is proved to form sufficient covering of the stone surface [21]. A possible problem on some brighter marble and types of limestone could be that the brushing treatment creates small crystals which can result in an increase in the diffuse reflectance of light [21]. This could make the stones look a bit more greyish than before treatment.…”

“…The third cluster identified by both SR-µFTIR microscopes showed strong Reststrahlen bands. Reststrahlen bands present the inverted and distorted calcite and oxalate bands created by measuring the reflected IR light [20,21]. Identified spectra with two-dimensional area maps for samples A5, B5/24 and C5/24 are presented in Figs.…”

Ananalytical Study of Marble Consolidation by Oxalate Precipitation Using Density, Ftir and Powder-XRD Measurements

“…Thus to prevent the deterioration and degradation of stone as a result of erosion and weathering, is very important to choose adequate methods of conservation and protection which acknowledge the chemical and physical character of diverse stone lithotypes. An effective treatment may be considered as one that protects the carbonate materials from degradation mechanisms, while not causing any damage to the stone itself [2]. A suitable method has been identified in the use of the calcium oxalate method that imitates the natural patina observed on monuments where the underlying marble substrate is usually well conserved.…”