Potassium carbonate

　　Colorless crystals or white granules. Hygroscopic. When containing sufficient moisture (16.36%), it is non-hygroscopic. Easily soluble in water, almost insoluble in ethanol. Aqueous solution is strongly alkaline. Relative density 2.043. Irritating.

　　Main Uses

　　Chemical and Material Fields:

　　Glass Manufacturing: Used as a flux and clarifying agent to lower the glass melting temperature and improve transparency and refractive index (especially for optical glass and picture tube glass).

　　Ceramics Industry: Promotes glaze melting, improves ceramic luster and density, used in glaze formulations for domestic and industrial ceramics. Detergents and Dyeing: Used as a water softener (removing Ca2⁺ and Mg2⁺ from water), or to adjust dye bath pH in dyeing to enhance dye adhesion.

　　Catalyst Carrier: Used in condensation reactions in organic synthesis (e.g., Knoevenagel reaction), or as a basic catalyst to promote transesterification reactions.

　　Food Industry (Food-grade Potassium Carbonate):

　　Acidity Regulator: Used in flour products such as noodles and biscuits to increase pH, enhance toughness and elasticity, and delay staling.

　　Leavening Agent: Used in combination with acid salts (e.g., sodium bicarbonate) to release CO₂ to make food fluffy (e.g., pastries, bread).

　　Preservative: Inhibits microbial growth in cured products to extend shelf life.

　　Must comply with food additive standards (e.g., China GB 1886.16-2015), and usage is strictly controlled (usually ≤0.05%-0.5%).

　　Agriculture and Medicine:

　　Potash Fertilizer: As a water-soluble potash fertilizer, supplements potassium for crops (especially suitable for chlorine-avoiding crops like tobacco and grapes), but due to higher cost, mostly used as foliar fertilizer.

　　Pharmaceutical Intermediate: Used in the synthesis of antibiotics, diuretics, etc., or as a pH regulator in pharmaceutical preparations.

　　Other Applications:

　　Gas Drying: Absorbs moisture and acidic impurities (e.g., CO₂, SO₂) from gases.

　　Metal Processing: Used for surface treatment of aluminum alloys to remove oxide films."