Stable solution of sodium and iron silicate, process for preparing said solution and uses thereof

Abstract

The present invention refers to a stable sodium and iron silicate solution that has a SiO2 to Na2O weight ratio from 1.5 to 2.5 and a total percentage of solids, expressed by the sum of SiO2 and Na2O, from 20% to 55%. The solution also has a soluble iron content, expressed by Fe, from 0.1% to 7%, and water content from 38% to 79.9%. The present invention also refers to the process for preparing the stable solution of sodium and iron silicate, which comprises the steps of: (a) providing a siliceous material containing iron; (b) submitting the siliceous material containing iron to a hydrothermal treatment with caustic soda under high temperature and controlled pressure; and (c) filtering the reacted solution to separate the reacted portion of the hydrothermal treatment from the unreacted portion. Additionally, the present invention refers to the uses of the stable sodium and iron silicate solution.