Potassium Carbonate — Frequently Asked Questions

A hot concentrated carbonate solution absorbs carbon dioxide to form potassium bicarbonate. Dropping the pressure then decomposes that bicarbonate back to carbonate, releasing the captured gas and regenerating the solvent. Because both absorption and regeneration run hot, the large cooling and reheating duty an amine system requires is avoided.

Because potassium gives a harder, more brilliant glass with a higher refractive index than sodium does. Soda-lime glass made with sodium carbonate is adequate for windows and bottles; optical, crystal and speciality glass uses potassium carbonate to get the clarity, hardness and light-handling properties those applications need.

Because the cation determines the physical form of the soap. Potassium salts of fatty acids are soft and highly soluble, giving a paste or liquid, while sodium salts are hard and form a bar. Any liquid or soft soap is therefore made with a potassium alkali, and potassium carbonate has been used for that since the material was literally pot ash.

Strongly. It readily absorbs atmospheric moisture and will cake and eventually deliquesce if left exposed, and it loses assay as it takes up water. It must be stored sealed in dry conditions and part-used packaging closed immediately. That same affinity for water is why it is also used as a drying agent.