Method for protecting and consolidating calcareous materials

Abstract

Embodiments provide methods for the protection and consolidation of calcareous materials. An exemplary method includes providing an aqueous solution of a hydroxycarboxylic acid, adjusting the pH of the aqueous solution by adding an alkaline agent, and applying the pH-adjusted aqueous solution to a calcareous mineral to form a conversion layer on the mineral. The calcareous mineral may, for example, be carbonate rock, particularly limestone and marble, or may be part of masonry material, aggregates, or fillers. Adherent conversion layers are readily formed at ambient temperatures and, therefore, methods provided are suitable for field application. Conversion layers so formed are provided as further embodiments.

We claim:  
     
         1 . A method of forming a conversion layer on an alkaline calcareous mineral, the method comprising: 
 providing an aqueous solution of a hydroxycarboxylic acid;    adjusting the pH of the aqueous solution by adding an alkaline agent; and    applying the pH-adjusted aqueous solution to the calcareous mineral.    
     
     
         2 . A method according to  claim 1 , wherein, in providing, the aqueous solution comprises L-(+)-tartaric acid.  
     
     
         3 . A method according to  claim 2 , wherein, in providing, the concentration of L-(+)-tartaric acid is within a range between approximately 0.06 mols per liter and approximately 0.25 mols per liter.  
     
     
         4 . A method according to  claim 3 , wherein, in providing, the concentration is approximately 0.16 mols per liter.  
     
     
         5 . A method according to  claim 2 , wherein, in adjusting, the alkaline agent comprises ammonium hydroxide.  
     
     
         6 . A method according to  claim 2 , wherein, in adjusting, the pH of the adjusted solution is between approximately 2.8 and approximately 5.0.  
     
     
         7 . A method according to  claim 6 , wherein, in adjusting, the pH of the adjusted solution is between approximately 3.4 and approximately 5.0.  
     
     
         8 . A method according to  claim 7 , wherein, in adjusting, the pH of the adjusted solution is approximately 3.9.  
     
     
         9 . A method according to  claim 4 , wherein, in adjusting, the pH of the adjusted solution is approximately 3.9.  
     
     
         10 . A method according to  claim 1 , further comprising: 
 rinsing the calcareous mineral with a secondary solution; wherein rinsing is performed after applying.    
     
     
         11 . A method according to  claim 10 , wherein, in rinsing, the secondary solution comprises calcium hydroxide.  
     
     
         12 . A conversion layer formed at a surface of an alkaline calcareous mineral by the method of  claim 1 .  
     
     
         13 . A conversion layer formed at a surface of an alkaline calcareous mineral by the method of  claim 2 .  
     
     
         14 . A conversion layer formed at a surface of an alkaline calcareous mineral by the method of  claim 9 .  
     
     
         15 . A conversion layer, according to  claim 13 , wherein the layer comprises an alkaline earth tartrate hydrate.  
     
     
         16 . A conversion layer, according to  claim 15 , wherein the layer comprises calcium tartrate tetrahydrate.  
     
     
         17 . A method of treating a material, the material comprising an alkaline calcareous mineral, the method comprising: 
 forming a conversion layer on the mineral; and    employing a formulation that chemically bonds with the conversion layer.    
     
     
         18 . A method according to  claim 17 , wherein the conversion layer acts as a primer, enhancing adhesion of other substances to the material.  
     
     
         19 . A method according to  claim 17 , wherein, in employing, the formulation comprises an alkoxysilane consolidant.  
     
     
         20 . A method according to  claim 17 , wherein, the formulation comprises a water-repellent.