Formation of a silicato complex of zinc in aqueous solution and its accelerating effect on the formation of silica scales in cooling water systems

This study elucidates the effect of zinc (Zn), which is an anticorrosive water additive, on the formation of silica scales from cooling water. In these experiments, the silica scales were analyzed by EPMA, and the results indicate that Zn is sorbed into the silica scales during formation. Measurements of the solubility of Zn(OH)2 at various concentrations of silicic acid demonstrate that Zn is present as a silicato complex of Zn (SCZ) in cooling water. From adsorption experiments of the SCZ on silica and alumina, which are major components of the silica scales, it can be concluded that the SCZ accelerates the formation of silica scales from cooling water.

Graphical abstractZinc species present as silicato complexes in cooling water accelerate the formation of silica scales.Figure optionsDownload full-size imageDownload high-quality image (41 K)Download as PowerPoint slideResearch highlights► Zinc in cooling water is present as a silicato complex of zinc (SCZ). ► The SCZ accelerates the adsorption of silicic acid on alumina and prevents the dissolution of silica. ► The SCZ accelerates the formation of silica scales from cooling water.