barium carbonate
White powder, insoluble in water, easily soluble in acid. Toxic and very versatile.
Physical and chemical properties
Barium carbonate, chemical formula BaCO3, molecular weight 197.35. Hexagonal fine crystals or white powder. Insoluble in water, density 4.43 g/cm3, melting point 1740 ℃ (8820 kPa-90 atmospheric pressure). 1450 ℃ decomposition, release carbon dioxide. Slightly soluble in water containing carbon dioxide, also soluble in ammonium chloride or ammonium nitrate solution to form a complex, soluble in hydrochloric acid and nitric acid to release carbon dioxide. poisonous. Used in electronics, instrumentation and metallurgical industries. Preparation of fireworks, signal flares, ceramic coatings, accessories for optical glass. Also used as rodenticide, water clarifier and filler.
Preparation
- Carbonization
Carbon dioxide is introduced into the barium sulfide solution for carbonization to obtain barium carbonate slurry. After desulfurization washing, vacuum filtration, drying at 300 degrees Celsius, and pulverization, the finished barium carbonate is obtained.
- Metathesis
The barium sulfide and ammonium carbonate are subjected to metathesis reaction, and then washed, filtered, dried, etc., to obtain the finished barium carbonate.
It can also be prepared by reacting barium chloride with potassium carbonate
- Toxic heavy petrochemical method
The witherite ore powder is reacted with the ammonium salt to generate soluble barium salt, and the ammonium carbonate is recycled and used. The soluble barium salt is added to the ammonium carbonate to precipitate the refined barium carbonate, which is filtered and dried to make the finished product. The obtained mother liquor can be recycled and reused.
Storage and transportation conditions
Store in a cool, ventilated warehouse. Keep away from fire and heat sources. Package is sealed. It should be stored separately from acids and edible chemicals, and should not be mixed. Storage areas should be provided with suitable materials to contain spills.
use
The auxiliary materials for ceramic coatings and optical glass are used in the manufacture of various electronic components such as electronic ceramics, PTC thermistors, and capacitors. Analysis of iron in calcium, magnesium, manganese and zinc. Identification and determination of halogens in organic compounds. It is used to make barium salts, pigments, fireworks, rodenticide pottery, and as fillers and water clarifiers. for catalysts. The production of electronic ceramics and purified water, the production of pigments, coatings or other barium salts for optical glass, barium magnetic materials, etc. are important chemical raw materials for the production of picture tube glass bulbs, magnetic materials and advanced optical glass. It can also be used in the treatment of excess sulfate in the chrome-plating electrolyte, in the white passivation solution of the zinc coating, and in the treatment of waste water.
Dangerous
Barium carbonate is a barium salt, which has strong toxicity. Barium carbonate will accumulate on the bones, causing the proliferation of bone marrow leukocyte tissue, resulting in chronic poisoning. The LD50 of barium carbonate is about 418mg/kg. For patients with acute barium carbonate poisoning, measures such as gastric lavage, enema, and emetics are usually used to excrete barium carbonate. At the same time, by taking potassium sulfate to react with barium carbonate, the toxic barium can be changed into insoluble barium sulfate precipitation to reduce toxicity. Potassium sulfate is used because barium carbonate poisoning may cause hypokalemia.
