Silicates and Metasilicates

Potassium silicate nSi02-K20, the ratio Si02/K20 of which ranges only from 2 to 2.5, has an action similar to that of sodium silicate. 

Magnesium silicate xSiOayMnO n H2O, a white powder that is very insoluble in water, has no action on aluminium. Talcum, a variety of magnesium silicate, suffers no alteration of its appearance in contact with aluminium. 

Solutions of sodium silicate 3Ca0 Si02 lead to a practically immediate, very superficial dissolution of aluminium, which remains below 5 p,m. 

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