ZINC CHLORIDE

Zinc chloride

Zinc chloride (zinc chloride, zinc dichloride) is a chemical compound of zinc with chlorine, having the formula ZnCl2.

It is a white, very hygroscopic crystal.

Properties
Physical properties
Molecular weight: 136.2954.
Melting point: 318 ° C.
Boiling point: 732 ° C.
Solubility in water at 20 ° C: 79.8%.
Chemical properties
Concentrated solutions have an acidic environment, as as a result of hydrolysis, ions are present in the water { displaystyle { ce {H ^ +}}} { displaystyle { ce {H ^ +}}}.

Receiving
dissolving zinc or its oxide in hydrochloric acid, followed by evaporation of the solution;
heating molten zinc in a chlorine stream.
Application
calico printing;
making dental cements;
antiseptic impregnation of wood (for example, sleepers);
cleaning the surface of metals from oxides before brazing (known as "Soldering acid");
component in the production of fiber;
refining of molten zinc alloys;
fractional analysis of coal samples;
in galvanic cells.
Toxicity
Zinc chloride is highly toxic and a strong irritant. Causes skin burns. Eye contact is especially dangerous.

After contact with skin, remove immediately with soap and plenty of water. In case of contact with eyes, rinse with plenty of water, use eye drops.

The minimum lethal dose (LD50) is 200 mg / kg. The fatal oral dose for humans is 3-5 g.

see also
Zinc and its halides:
Zinc fluoride
Zinc bromide
Zinc iodide
Chlorides

Zinc Chloride is the name of chemical compounds with the formula ZnCl 2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white and well
soluble in water. ZnCl 2 itself is hygroscopic and even spreads. Therefore, samples must be protected from sources of moisture, including water vapor present in the ambient air.
Zinc chloride is widely used in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with such a chemical composition is known, except very
rare mineral of simoncolleite Zn 5 (OH) 8 Cl 2 · H 2 O.

Zinc chloride is also called zinc chloride and zinc dichloride. Zinc Chloride This chemical reagent has a fairly wide range of applications. Zinc chloride (ZnCl2) is white crystals or flakes, sometimes with a yellowish tinge, capable of absorbing water vapor from the environment.

Main characteristics
- Complete lack of smell.
- Solubility, which differs depending on the temperature of the water. For example, at a temperature of 25 ° C in 100 g of water, you can dissolve 432 g of zinc chloride, and at a temperature of 100 ° C - already 614 g. On average, the compound has 80 percent solubility in water. Along with water, acetone, ethyl alcohol, ether and glycerin are good solvents for zinc chloride.
- Not flammable.
- It is toxic by inhalation, in contact with the skin and mucous membranes, it causes chemical burns, therefore it is necessary to work with this substance using protective equipment.

Production
Industrial production of zinc chloride is carried out in two ways. In the first, zinc is dissolved in hydrochloric acid. Moreover, for this method, both pure zinc and its oxides and even zinc-containing secondary raw materials are suitable. After dissolution, the solution is evaporated.

The second method involves the use of zinc in liquid or (less often) granular form. Chlorine is fed to the zinc, while the zinc is heated to a temperature of 420 ° C.

Zinc chloride is purified by sublimation; production standards are prescribed in GOST 7345-78 and 4529-78.

Storage and transportation
Zinc dichloride The storage area must be dry and well ventilated. It is important to exclude the possibility of spillage and spillage of the compound (if it is transported in the form of a solution), for which it is recommended to use sealed containers. The shelf life, on average, is from 2 months to six months.

Zinc dichloride is transported in accordance with the rules for the carriage of goods that apply to this type of transport. During transportation, the reagent must be hermetically packed, and the container must be marked in accordance with GOST 19433-88.

ZnCl2 is transported and stored usually in sealed tanks or barrels.

Application
Zinc chloride is widely used in completely different fields of industry. The most common areas of its use:
- In dentistry for the production of cements.
- For printing drawings on calico, in the production of dyes, including for dyes of cotton fabrics, in the light industry.
- For the production of refractory impregnations of various materials.
- For oil refining.
- As a dehumidifier.
- In the coal industry - for conducting fractional tests of coal samples.
- In woodworking for antiseptic impregnation of wood.
- In metallurgy for the refining of melts, for the purification of metals from the oxide layer.
- In the manufacture of batteries.

- To improve the quality of soldering. This is one of the main areas of application for this reagent, therefore its aqueous solution is widely known as "soldering acid".