Abstract

Synthetic akali silicates, M₂O·mSiO₂·nH₂O, where M = Li, Na, and K, are manufactured as liquids or glasses that readily dissolve in water to form alkaline solutions. These silicates contain a complex mixture of polymeric species that vary as a function of modulus, m, of the material, solution concentration, impurities content, and pH value. The polymer chemistry of silicates influences the properties and function of these materials in a variety of applications including detergency, water treatment, mineral beneficiation, bleach stabilization, and as a raw material for the syntheses of silica sols, gels and precipites, zeolites, clays, and other siliceous materials. The speciation and structure of silicates have been studied using a broad variety of analytical methods including Fourier transform infrared, ft–nmr, laser Raman, and X-ray photoelectron spectroscopic techniques. The current article discusses the properties of the synthetic alkali silicates that determine their function in a variety of commercial applications. Economic, manufacturing, regulatory and environmental aspects of silicate production and usage are reviewed.