International name: Natrii Hydroxidum, Sodium Hydroxide

Synonyms: sodium hydroxide, caustic, caustic soda, caustic alkali

Chemical formula: NaOH

Appearance: hygroscopic granules of white color

Manufacturing: Russia, Poland

Packaging and storage: 25 kg bag; up to 1 year

 

Description

Caustic soda is a strong alkali, when it is combined with water, a large amount of heat is released. Aqueous solutions of caustic soda have a strong alkaline reaction. Caustic soda is particularly good at corroding materials of organic origin. Registered as food additive E524.

They produce a solid and liquid caustic. The sodium hydroxide solid is released as spherical or hemispherical granules and white scales. According to GOST 2263-79 the following brands of sodium hydroxide are produced depending on the method of production.

The mercury production method is the easiest and most convenient, but it causes considerable damage to the environment as a result of evaporation and leakage of metallic mercury.

The diaphragm method is more effective, environmentally friendly and less energy-intensive. However, caustic alkali, obtained by the mercury method, is much cleaner than those obtained by the diaphragm method. For some industries this is important. So, in the production of artificial fibers can be used only caustic, obtained by the mercury method.

 

Properties

  • Insoluble in acetone and ethers;
  • It is readily soluble in glycerol, ethanol and methanol (alcohol solutions);
  • Caustic is very hygroscopic, so soda should be packaged in waterproof containers and stored in a dry room;
  • Non-flammable, the melting point is 318 ° C;
  • The boiling point is 1390 ° C;
  • As a strong base, caustic soda can form explosive combustible gas (hydrogen);
  • A fire hazard situation also arises in the case of contact of sodium alkali with ammonia;
  • In a molten state, it can destroy porcelain and glass

Receiving

Caustic soda can be obtained by chemical methods such as calcareous and ferritic. The first is realized by reaction of a solution of soda with lime at rather high temperatures (about eighty degrees). As a result, we get a solution of NaOH with a precipitate in the form of calcium carbonate. The latter is separated by raising the temperature and evaporating the solution to the state of molten sodium hydroxide. The ferritic method takes place at much higher temperatures, which exceed a thousand degrees, so they are suitable for use only under special conditions.

Electrochemical methods are much larger, and some of them demonstrate optimal results. True, it is worth noting the technical complexity of the realization of such a way of obtaining sodium hydroxide. One of the basic processes of electrolysis, which allows to obtain a pure substance, which can then be used in industry, uses a solution of gallite. As a result of the reaction, several substances are simultaneously produced simultaneously: caustic soda, chlorine, hydrogen and oxygen. There are several such methods, and each of them demonstrates its advantages and disadvantages.

 

Application

Today, sodium hydroxide is the most important alkali in industry.

About half of the sodium hydroxide produced is used directly in the chemical industry to produce various organic and inorganic substances: phenol, resorcinol, b-naphthol, sodium salts (hypochlorite, phosphate, sulfide, aluminates);

  • in the petrochemical industry for refining petroleum products;
  • in the pulp and paper industry in the production of paper, cardboard, man-made fibers;
  • in the textile industry in the production of viscose silk and in bleaching fabrics;
  • in non-ferrous metallurgy.

It is part of the solutions for degreasing and removing from the surface parts of oil and grease films. The main ingredient of an alkaline solution for removing tin from steel. It is part of the solutions of chemical copper plating, gilding of copper and brass products, chemical chromium plating, nickel plating, chemical silvering of glass.

  • in the production of various household chemical products, for example, detergents, means for cleaning sewers, etc .;
  • for degreasing and processing equipment and containers at food industry enterprises (dairies,
  • fat-and-oil plants, distilleries, tobacco industry);
  • in the food industry for refining oil, as an acidity regulator.

Safety requirements

Sodium hydroxide is a corrosive and corrosive substance. It refers to substances of the second hazard class. Therefore, care must be taken when working with it. In case of contact with skin, mucous membranes and eyes, serious chemical burns occur. When contact with mucous surfaces with caustic alkali, it is necessary to wash the affected area with a stream of water, and if it gets on the skin with a weak solution of acetic acid. When working with caustic sodium, the following protective measures are recommended: chemical splash protection glasses for eye protection, rubber gloves or rubber-coated gloves for protecting hands, for body protection, chemically resistant clothing impregnated with vinyl or rubberized suits

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