Preparation, Properties and Uses Of Zinc Carbonate
Zinc Carbonate with the formula ZnCO3 is an inorganic compound that exists naturally as smithsonite – which is named after renowned English scientist James Smithson.
This white crystalline solid is insoluble in water and alcohol, and soluble in acids and alkalis. This odorless zinc ore is a pivotal zinc source that is easily convertible to other zinc compounds. Its application in different industries has led to its increase in demand.
Preparation Of Zinc Carbonate
• Zinc Carbonate is produced by the treatment and reaction of cold solutions of zinc sulphate and potassium bicarbonate.
Potassium carbonate, potassium sulphate, carbon dioxide and water are also formed in this reaction.
KHCO3 + ZnSO4 = ZnCO3 + K2CO3 + K2SO4 + CO2 + H2O
• Zinc Carbonate can be prepared by heating solely urea or a mixture of urea and ammonia and carbon dioxide with water in a sealed vessel with either zinc ash, die casting ash, or zinc skimming. After the dissolution of zinc, the solution is then cooled, filtered, and further mixed with zinc dust and used in the precipitation of heavy metals.
The solution is then heated for the second time for iron precipitate removal and for the third time for the precipitation of the dissolved zinc into the basic form of zinc carbonate. The zinc carbonate is then washed and dried.
• Zinc Carbonate can also be formed by a precipitation reaction which involves the treatment and mixture of a strong solution of sodium carbonate and a strong solution of zinc chloride.
ZnCl2(aq) + Na2CO3(s) = ZnCO3(s) + NaCl(aq)
• Zinc Carbonate can also be obtained by reacting zinc sulphate with sodium carbonate.
This reaction also produces soluble sodium sulphate.
ZnSO4 + Na2CO3 = ZnCO3 + Na2SO4
• Zinc Carbonate can also be synthesized along with potassium chloride by reacting Zinc chloride and potassium carbonate.
ZnCl2 + K2CO3 = ZnCO3 + 2KCl
• Zinc oxide can be reacted with water and two atoms of sodium hydroxide to form zincates which react with carbon dioxide to form zinc carbonate, sodium carbonate, and water.
ZnO + NaOH + H2O = Na2Zn(OH)4
Na2Zn(OH)4 + 2 CO2 = ZnCO3 + Na2CO3 + 2 H2O
• Zinc Carbonate can also be prepared by the reaction of zinc sulphate and sodium bicarbonate (sodium hydrogen carbonate). Soluble sodium sulphate, carbon dioxide and water are also formed in this reaction.
ZnSO4 + NaHCO3 = ZnCO3 + Na2SO4 + CO2 + H2O
• Zinc Carbonate can also be produced by the mixture of two reactants that have been dissolved in aqueous microemulsions and by grinding zinc sulphate, aluminum carbonate, and cobalt sulphate heptahydrate at room temperature.
Chemical Properties Of Zinc Carbonate
• Zinc carbonate undergoes calcination (breakdown due to heat applied) to form carbon dioxide and zinc oxide.
ZnCO3 + heat = ZnO + CO2
• Zinc carbonate reacts with dilute acids to produce other zinc salts.
It reacts with sulfuric acid to form zinc sulphate, carbon dioxide, and water.
H2SO4 + ZnCO3 = ZnSO4 + CO2 + H2O
It reacts with hydrochloric acid to form zinc chloride, carbon dioxide, and water.
2 HCl +ZnCO3 = ZnCl + CO2 + H2O
It reacts with nitric acid to form zinc nitrate, carbon dioxide, and water.
2 HNO3 + ZnCO3 = Zn(NO3)2 + CO2 + H2O
Physical Properties Of Zinc Carbonate
Zinc Carbonate is a white solid and crystalline powder that is insoluble in water, acetone, and alcohol, soluble in acids and alkali, and partly soluble in ammonia.
This odorless substance decomposes at 300°C and has a +2 oxidation number. It also has a molar mass of 125.4 g/mol and a density of 3.5 g/cm3.
Uses Of Zinc Carbonate
• It is used in the treatment of skin diseases.
• It is used in the production of a wide range of cosmetics products like which include make-up, bath, shaving, and skin products amongst others.
• It is used in the manufacturing of zinc oxide particles.
• It is used as an astringent.
• In the agricultural sector, it is used to enhance growth in plants.
• It undergoes calcination to form other zinc compounds.
• In the medical industry, it is used as an antiseptic and also used to eradicate toxic gases from respiratory systems.
• It is used as raw material, fire retardant, and as a solidification agent in the manufacturing of rubber and its products such as car tires, shoe soles, gloves, and lots more.
• In the petroleum industry, it is used to absorb sulphur.
• It is used as a catalyst in organic reactions.
• It is used as an additive in animal feeds and also helps in the development and strengthening of an animal’s bones.
Its absence can also cause retardation in an animal’s growth.
• It is also a component of zinc anodes which are used in the batteries of electrical appliances.
• It is used as an ingredient in toothpaste for the protection of whitened teeth.
• It is used in the reduction of corrosion in steel.
• It is used in the production of paints due to its white pigmentation.
• It is also used as a sputtering target during the deposition of vapour.
• It is used in the production of porcelain and pottery.
• It is also used as an inorganic salt.
• It is used to clean and protect wounds in animals.
Health Concerns
Zinc Carbonate is very lethal to our health hence should be handled with adequate care.
Contact with the skin and eyes can cause skin and eye irritation respectively, while ingestion can use damage to the stomach, vomiting, and nausea.
Inhalation of its fumes can cause wheezing, discomfort in the chest, coughing, bleeding, dry throat while long-term exposure can lead to damages to the liver.
To prevent any of these from happening, you must ensure you wash your hands thoroughly after handling this substance, wear safety clothing, gloves, and protective goggles.
Exposure to excess heat or open flame can also lead to an explosion, so you must endeavor to save this substance in a properly sealed container and store it in a place without excess heat.
