Potassium carbonate

Description

Potassium carbonate(K2CO3) is a white, crystalline, salt that forms basic aqueous solutions used in the production of fertilizer, glass, ceramics, explosives, soaps, chemicals, and wool treatments. It was the main compound once referred to as potash, although the term today is not reserved exclusively for potassium carbonate, but for several potassium salts. In the fertilizer industry, potash refers to potassium oxide, K2O, rather than potassium carbonate.

Chemical properties

A white salt, soluble in water (insoluble in ethanol) which forms a strongly alkaline solution. Potassium carbonate can be made as the product of potassium hydroxide's absorbent reaction with carbon dioxide. It presents a large capacity to absorb moisture.Corrosive to metals and tissue. Density 12.8 lb /gal. It has low solubility in ethanol, acetone, and many other common organic solvents. Used to make soaps, other potassium compounds, in liquid fertilizers.

The Uses of Potassium carbonate

Potassium carbonate is a common flux combined with titanium dioxide to produce frits used in ceramics. Potassium carbonate is used in the chemical industry as a source of inorganic potassium salts (potassium silicates, potassium bicarbonate), which are used in fertilizers, soaps, adhesives, dehydrating agents, dyes, and pharmaceuticals. Potassium carbonate used to make potassium lye produces soft soaps, which are liquids or semisolids rather than solids. Other uses of potassium carbonate includes use as a fire suppressant in extinguishers, as a CO2 absorbent for chemical processes and pollution control, an antioxidant in rubber additives, and in pharmaceutical formulations.

Definition

ChEBI: Potassium carbonate is a potassium salt that is the dipotassium salt of carbonic acid. It has a role as a catalyst, a fertilizer and a flame retardant. It is a carbonate salt and a potassium salt.

Production Methods

Potassium carbonate can be obtained from ash or by electrolysis of potassium chloride. Another method involves reacting potassium hydroxide with carbon dioxide. The resulting liquid carbonate contains approximately 50% potassium carbonate in water. However, the solid product, which contains over 70% potassium carbonate, is expensive and only suitable for certain types of acidic soil. Additionally, neutralizing caustic potash with carbon dioxide also yields potassium carbonate.

Air & Water Reactions

Water soluble. Addition of water evolves heat.

Reactivity Profile

Potassium carbonate neutralizes acids exothermically to form salts plus water. Reacts with certain metals (such as aluminum and zinc) to form oxides or hydroxides of the metal and generate gaseous hydrogen. May initiate polymerization reactions in polymerizable organic compounds, especially epoxides. May generate flammable and/or toxic gases with ammonium salts, nitrides, halogenated organics, various metals, peroxides, and hydroperoxides. May serve as a catalyst. Reacts when heated above about 84°C with aqueous solutions of reducing sugars other than sucrose, to evolve toxic levels of carbon monoxide [Bretherick, 5th Ed., 1995].

Health Hazard

TOXIC; inhalation, ingestion or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Fire Hazard

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.

Agricultural Uses

Potassium carbonate is used in agriculture and food production. Potassium carbonate is used as a spray or drip fertilizer and also as a constituent of compound fertilizers. Its high water solubility and alkaline property make it useful for supplying potassium to acidic soils, especially in vineyards and orchards. Dutch-processed cocoa uses potassium carbonate as an alkalizing agent to neutralize the natural acidity of cocoa. It is used to produce food additives like potassium sorbate and monopotassium phosphate.

Industrial uses

Potassium carbonate is used for numerous applications. Its primary use is in the production of specialty glasses and ceramics. It is used to make optical glass, glass used for video screens in televisions and computers, and laboratory glassware. Its is used in certain glasses rather then cheaper sodium carbonate owing to its better compatibility with lead, barium, and strontium oxides incorporated in these glasses. These oxides lower the melting point of glass and produce a softer glass. Potassium carbonate has a higher refractive index than sodium carbonate producing a more brilliant glass. Potassium carbonate is a common flux combined with titanium dioxide to produce frits used in ceramics. A frit is a calcined mixture of fine silica, a pigment, and a flux that is ground a specific particle size and used to produce glazes, enamels, and additives in glass making.

Safety Profile

Poison by ingestion. A strong caustic. Incompatible with KCO, chlorine trifluoride, magnesium. Mutation data reported. When heated to decomposition it emits toxic fumes of K2O.

References

https://en.wikipedia.org/wiki/Potassium_carbonate
https://www.drugs.com/inactive/potassium-carbonate-106.html
http://www.sciencelab.com/msds.php?msdsId=9926681
https://pubchem.ncbi.nlm.nih.gov/compound/Potassium-Carbonate
Solubility of Potassium Carbonate and Potassium Hydrocarbonate in Methanol DOI:10.1021/JE020012V