sodium metasilicate pentahydrate

Description

sodium metasilicate pentahydrate/ silicic acid disodium salt
The Metso® range of Sodium Metasilicate Pentahydrate Sodium Metasilicate has been used for a long time in alkaline cleaning agents for the household and industrial sectors. Sodium Metasilicate provides both silica and alkalinity in a molar ratio of 1:1 between silica and sodium oxide, which makes it especially suitable for hard surface cleaning. Its multifunctional cleaning properties enhance the removal of fatty and particulate soil in both soft and hard water. The corrosion inhibiting properties of Sodium Metasilicate help protect both metal and non-metal surfaces. Metso Sodium Metasilicate Pentahydrate granules are white and free-flowing. The product is characterized by: ■ high dissolution rate, even in cold water ■ negligible insoluble residue ■ high mechanical strength ■ low dust content
Alkalinity The alkalinity provided by Metso Sodium Metasilicate Pentahydrate saponifies fatty soil which makes them readily dissolvable. The saponified fatty soil acts as a soap and contributes to the emulsification and removal of oily and greasy soil. The alkalinity also neutralizes acid soils, and breaks down protein and starch. The high active alkali and minimum inactive alkali content makes Metso Sodium Metasilicate Pentahydrate an economical choice for cleaning applications. The table shows the active and inactive alkali content for common industrial alkalies.
Buffering action It is very important to keep the pH at a high and constant level throughout the cleaning process. Acidic soils lower the pH of the cleaning solutions below that required for optimum cleaning by the surfactants and other ingredients. Metso Sodium Metasilicate Pentahydrate is an excellent buffer and the effect of acid soil is minimized. Compared to other alkalis, with the exception of sodium hydroxide, Metso Sodium Metasilicate Pentahydrate keeps the cleaning solution at constant pH over an extensive loading of acidic soil, see figure below. A constant pH level contributes to the effectiveness of the silicate in cleaning functions involving emulsification of oils and grease and suspension of particulate soils. A declining pH will lead to a reduction of the overall performance of the cleaning solution.
Corrosion inhibition By forming a protective barrier, the soluble silica content of Metso Sodium Metasilicate Pentahydrate acts as a corrosion inhibitor and protects metal, glass and ceramic surfaces against alkaline attack from other detergent ingredients such as phosphates, synthetic detergents and other alkalis. The mechanism of corrosion inhibition on metal is shown in the figure left. The monomeric species of silica are negatively charged and will adsorb onto the metal surface and form a thin monomolecular film, which will inhibit corrosion. The film does not build on itself and will not form excessive scale. The film is an electrical insulator and blocks the electrochemical reactions of corrosion, yet is thin enough that it does not obstruct water flow.
Metso Sodium Metasilicate Pentahydrate provides: ■ Alkalinity that saponifies fatty soils and make them easy to dissolve. The saponified fatty soil contributes to the cleaning process. ■ Silica that disperses the soil in the solution and prevents it from redepositing on the surface. ■ Excellent buffering capacity which means that the pH is kept constant throughout the process. ■ Sequestration of calcium and magnesium ions in order to soften the water. ■ Protection against corrosion on metal, china and glass surfaces. ■ Stabilization of the bleaching agent during the washing process.
uses
Sodium Metasilicate reacts with acids to produce silica gel.
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Cements and Binders - dehydrated sodium metasilicate forms cement or binding agent.
Pulp and Paper - sizing agent and buffer/stabilizing agent
Soaps and Detergents - as an emulsifying and suspension agent.
Automotive applications - decommissioning of old engines (CARS program), cooling system sealant, exhaust repair.
Egg Preservative - seals eggs increasing shelf life.
Crafts - forms "stalagmites" by reacting with and precipitating metal ions.