The calcium chloride , is a salt of Calcium. It is a product Anhydre and it is required for its exothermic qualities. Its Chemical formula is CaCl₂, It east déliquescent and very soluble in the Eau. It is a solid salt with the ambient Température, which behaves like a typical salt of Halogénure, with in particular good a electric Conductivité with the state Liquide and chemical bonds ionic. It is in particular used in units of Réfrigération, for the salting of the roads by great colds, or in the Ciment S. It can be obtained directly starting from the Craie, but it is also produced in great quantities like produces secondary reactions implemented in the Procédé Solvay. It is a material very Hygroscopique which must thus be preserved in well closed containers.

Chemical properties

The calcium chloride can be used as tank of Ion S Calcium in solution, for example to separate another ion by Précipitation by using the fact that many calcium salts are insoluble. The following reaction makes it possible for example to separate the ions Phosphate S in solution:

3 CaCl₂ (aq) + 2 K₃PO₄ (aq) → Ca₃ (PO₄) ₂ (S) + 6 KCl (aq)

The molten calcium chloride can be electrolyzed to obtain Calcium Métal:

CaCl₂ (L) → Ca (S) + Cl₂ (G)

One can directly find it in chalk.

Preparation

The calcium chloride is a secondary product of the manufacture of Sodium carbonate by the Procédé Solvay. It can also be prepared while making react Hydrochloric acid and Carbonate of calcium:

CaCO₃ (S) + 2 HCl (aq) → CaCl₂ (aq) + H₂O (L) + CO₂ (G)

Whatever the technology of production used, the calcium chloride is in liquid form too diluted (approximately 15%) to be transported in an economic way. In order to make the product more economic in its transport, it can undergo various phases of concentration.

These operations are carried out by a heating towards vacuum 180°C via evaporators for several purposes to reach concentrations close to 75%.

One reaches the commercial concentrations close to:

1. 33% (CaCl2 6:00 ₂0 diluted - density 1,33 - temperature of crystallization - 30 °C)
2. 42% (CaCl2 6:00 ₂0 diluted - density 1,41 - temperature of crystallization + 18 °C)
3. 77 - 82% (CaCl2 2:00 ₂0 in the form of spangles, pellets or powders - temperature of crystallization + 180 °C)
4. > 96% (CaCl2 0:00 ₂0 in the form of spangles, pellets or powders - temperature of crystallization > 180 °C)

It is in a majority of the cases the report/ratio price of transport/price of product which will determine the form used.

In a vast majority of the cases, the calcium chloride is used in its liquid form.

Uses

Million ton S of calcium chloride is produced annually with only the USA. In 1990, its course was of 182 $ per ton. It is a compound which has many applications:

• Because of its very hygroscopic character, it can be used to dry the air, other gases or liquids organic. When it absorbs the water or the steam of the substance to be dried, it is transformed into Saumure:

CaCl₂ + 2:00 ₂O → CaCl₂·2H₂O

the process of dissolution of calcium chloride is very Exothermique and of the Température S higher than 60°C can be reached quickly. The ingestion of calcium chloride pastilles can thus cause low registers Brûlure S.

• Because of Heat emitted during the process of dissolution, the calcium chloride can be used to dissolve Glace. Contrary to sodium chloride, it is not harmful for the ground and the Plante S. It can also act at temperatures lower than the Sodium chloride. For this use, it is appeared as small balls of some Millimètre S of Diamètre (as on the Photo at the beginning of the page).

• It is used at the time of the mixture of the Béton to accelerate to make the catch and it hard more.

• It is used on certain Autoroute S to fix the Poussière: while reacting with the moisture of the air, it makes it possible to maintain a fine layer liquid on the road surface what maintains dust.

• the calcium chloride has a bitter taste. He is added to food cooked industrially to increase the cellular hardness of food, such as for example in the Cornichon S, Olive S, compotes of Pomme S, bean-princess out of bottles.

• It is also used in molecular biology, that Ci indeed makes it possible to make bacteria qualified by degrading their lipopolysaccharides of surface. It makes them thus suited to the transformation by a vector.

• It can also be used into food, in particular to solidify the Alginate S, gelling.

• the solutions of CaCl₂ have the property to make the walls cellular of certain bacteria more porous (in particular E. coli). That makes of it a product used in laboratory in genetic research.

Safety

The calcium chloride is irritating. It must be handled with gloves. It is relatively without danger to be handled, but it should not be introduced. As it reacts in an exothermic way with water, it can cause burns of the Bouche or esophagus.

R: 36 (irritating for the eyes)

References

1. NR. NR. Greenwood, A. Earnshaw, Chemistry off the Elements , 2nd ED., Butterworth-Heinemann, Oxford, the U.K., 1997.
2. Handbook off Chemistry and Physics , 71st edition, CRC Close, Ass Arbor, Michigan, 1990.
3. Calcium Chloride Handbook from Dow Chemical (pdf 1.6MB)

Random links:

Vincent Vittoz | Stick Harbor | Kloetinge | Alonso Hernández Puertocarrero | Jessica Jones | Exploit_de_navigateur