Physical and chemical properties

physical properties

Sodium carbonate is white odorless powder or granules at room temperature, with a density of 2.54g/cm3 and a melting point of 856ºC. Soluble in water, also soluble in glycerin, 20 grams of sodium carbonate can be dissolved per 100 grams of water at 20 ° C, the solubility is the largest at 35.4 ° C, 49.7 grams of sodium carbonate can be dissolved in 100 grams of water, slightly soluble in absolute ethanol, insoluble Compared with propanol, the PH of 1% aqueous solution is 11.5, it can conduct electricity in aqueous solution or molten state, and the aqueous solution has astringent taste and slippery feeling. Sodium carbonate is hygroscopic, and it will gradually absorb 1mol/L water (approximately = 15%) when placed in the air. Its hydrates include Na2CO3·H2O, Na2CO3·7H2O and Na2CO3·10H2O [6].

chemical properties

· The aqueous solution of sodium carbonate is alkaline and has certain corrosiveness. It can undergo metathesis reaction with acid, and can also undergo metathesis reaction with some calcium salts and barium salts. The solution is alkaline and can turn phenolphthalein red.

Stability

Strong stability, but can also be decomposed at high temperature to generate sodium oxide and carbon dioxide：

Long-term exposure to the air can absorb moisture and carbon dioxide in the air, generate sodium bicarbonate, and form hard lumps：

The crystalline hydrate of sodium carbonate (Na2CO3·10H2O) is easily weathered in dry air：

Use

Sodium carbonate is one of the important chemical raw materials. It is widely used in light industry daily chemical, building materials, chemical industry, food industry, metallurgy, textile, petroleum, national defense, medicine and other fields. It is used as a raw material for the manufacture of other chemicals, cleaning agents, Detergents are also used in the fields of photography and analysis. Followed by metallurgy, textiles, petroleum, national defense, medicine and other industries. The glass industry is the largest consumer sector of soda ash, consuming 0.2 tons of soda ash per ton of glass. Among the soda ash used in industry, it is mainly applied to light industry, building materials and chemical industry, accounting for about 2/3, followed by metallurgy, textiles, petroleum, national defense, pharmaceutical and other industries [8].

1. The glass industry is the largest source of consumption of soda ash, 0.2t of soda ash is consumed per ton of glass. Mainly used in float glass, picture tube glass bulb, optical glass, etc.

2. Used in chemical industry, metallurgy, etc. The use of heavy soda ash can reduce the flying of alkali dust, reduce the consumption of raw materials, improve working conditions, and improve product quality. At the same time, it can reduce the erosion of alkali powder on refractory materials and prolong the service life of the kiln.

3. As a buffer, neutralizer and dough improver, it can be used in cakes and flour-made foods, and it can be used in moderation according to production needs.

4. Used as detergent for wool rinsing, bath salt and medicine, and alkaline agent in tanning leather.

5. Used in the food industry as a neutralizer and leavening agent, such as in the manufacture of amino acids, soy sauce and flour-based foods such as steamed buns and bread. It can also be made into alkaline water and added to pasta to increase elasticity and extensibility. Sodium carbonate can also be used in the production of monosodium glutamate

6. Reagents for color TV

7. Used in the pharmaceutical industry as antacids and osmotic laxatives.

8. Used for chemical and electrochemical degreasing, chemical copper plating, aluminum etching, electrolytic polishing of aluminum and alloys, chemical oxidation of aluminum, sealing after phosphating, antirust between processes, electrolytic stripping of chromium plating and Remove chromium oxide film, etc., also used in pre-plating copper, steel plating, steel alloy plating electrolyte

9. In the metallurgical industry, it is used as a smelting flux, a flotation agent for ore dressing, and a desulfurizer in steelmaking and antimony smelting.

10. Used as water softener in printing and dyeing industry.

11. In the tanning industry, it is used for degreasing raw hides, neutralizing chrome tanned leather and increasing the alkalinity of chrome liquid.

12. Benchmark for calibrating acid solution in quantitative analysis. Determination of aluminum, sulfur, copper, lead and zinc. Test urine and whole blood glucose. Co-solvent for the analysis of silica in cement. Metallographic analysis, etc.