How is Calcium chloride made?

Commercial calcium chloride is mainly synthesized with three manufacturing processes as follows:

Ammonia-soda process

CaCl2 is a by-product in the production of sodium carbonate. The process is also called Solvay process in which the reaction between sodium chloride (salt brine) with calcium carbonate (limestone), and ammonia as a catalyst (1):

2 NaCl + CaCO3 → CaCl2 + Na2CO3

Limestone-hydrochloric acid Process

React hydrochloric acid with calcium carbonate (limestone).

2HCl + CaCO3 → CaCl2 + H2O + CO2

Natural brine process

Purification of naturally-occurring brines (such as salt lakes) by removing magnesium with adding Ca(OH)2, and precipitating sodium chloride by increasing the concentration of CaCl2.

Specification

Two types

According to the different amount of crystalline water, calcium chloride can be divided into two types: 

1.Dihydrate: the main type in the market for deicing and dust control.

2.Anhydrous: commonly as a drying agent for gases and liquids. It can attract 6 times moisture: CaCl2 + 6H2O → CaCl2 · 6H2O

Also with hexahydrate form, but seldom in the market.

CaCl2 can also be classified into food and industrial grades based on the different uses.

Other names:       Calcium dichloride

                              Calcium (II) chloride

                              Calcium chloride anhydrous or dihydrate

CAS number:       10035-04-8 (dihydrate)

                              10043-52-4 (anhydrous)

Chemical formula: CaCl2 (anhydrous)

                              CaCl2 · 2H2O (dihydrate)

                              CaCl2 · 6H2O (hexahydrate)

Molecular weight: 110.99 (anhydrous)

                              147.02 (dihydrate)

Properties

Appearance

White, odourless, both hygroscopic and deliquescent (converts to a liquid brine after absorbing enough moisture). It is supplied in the form of powder/pellet/flake/granular or solution depending on the requirements of the application.

Solubility

Highly soluble in water with the solubility 1g/1.5ml at 25°C and soluble in ethanol. It dissociates calcium ion and chloride ion when dissolved in water with the following equation: CaCl2 (aq) → Ca2+ (aq) + 2Cl– (aq) 

Reactions

CaCl2 is commonly reacts with the below ingredients and with the chemical

reactions:

Sodium carbonate: CaCl2 + Na2CO3 → CaCO3 + 2NaCl

Sodium bicarbonate : CaCl2 + 2NaHCO3 → CaCO3 + 2NaCl + H2O + CO2

Potassium carbonate: CaCl2 + K2CO3 → CaCO3 + 2KCl 

Sodium phosphate : CaCl2 + Na3PO4 → Ca3(PO4)2 + NaCl 

Sodium hydroxide: CaCl2 + 2NaOH → Ca(OH)2 + 2NaCl