Electrolysis of Sodium Silicate Solutions Using Cation-Exchange Membranes

Abstract

The electrolysis of sodium silicate solutions was studied at various temperatures, current densities, and concentrations. By using a cation-exchange membrane, NaOH was recovered at high current efficiency in the cathodic compartment. Sodium silicate solutions in the anodic compartment were upgraded to products of higher SiO₂/Na₂O ratios. The deposition of silica on anodes strongly inhibits smooth operation during electrolysis, and a semibatch method is described to overcome this difficulty.