Calcium Carbonate Scale

Definition

The most common industrial scale, formed when concentrated calcium and carbonate exceed solubility, especially at hot surfaces.

Formation depends on calcium concentration and carbonate availability, which pH governs strongly, and it exhibits inverse solubility that makes it dangerous at heat transfer surfaces. Cooling towers are vulnerable because evaporation concentrates calcium and alkalinity while carbon dioxide stripping drives pH up. It responds to all three major levers of concentration, pH, and temperature, and the LSI, RSI, and PSI indices are built around it.

Related concepts

pH Effect on Carbonate Speciation · Scale Indices · Carbonate Equilibrium

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Part of The Blueprint of Water · 🧪 chemistry